Learning Curve Analysis of Transvaginal Natural Orifice Transluminal Endoscopic Surgery in Treating Ovarian Cysts: A Retrospective Cohort Study

Learning Curve Analysis of Transvaginal Natural Orifice Transluminal Endoscopic Surgery in Treating Ovarian Cysts: A Retrospective Cohort Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Learning Curve Analysis of Transvaginal Natural Orifice Transluminal Endoscopic Surgery in Treating Ovarian Cysts: A Retrospective Cohort Study Dan Feng, Tianjiao Liu, Li Xiao, Xin Li, Lu Huang, Li He, Yonghong Lin This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4152484/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 25 Jul, 2024 Read the published version in BMC Women's Health → Version 1 posted 10 You are reading this latest preprint version Abstract Background： Transvaginal Natural Orifice Transluminal Endoscopy (vNOTES) is regarded as a challenging surgical technique to learn but is promising in reducing perioperative pain and significantly improves the cosmetic outcomes. Previous studies on the learning curve analysis of vNOTES mainly focuses on the hysterectomy approach, while the vNOTES ovarian cystectomy’s learning curve was merely reported thought more frequently performed than vNOTES hysterectomy. Therefore, this study seeks to analyze the learning curve of three surgeons with varying levels of experience in performing endoscopic surgery for the treatment of ovarian cysts using vNOTES. Methods: A total of 127 patients with ovarian cysts of a variety of pathological types were treated by vNOTES ovarian cystectomy performed by three surgeons of different levels of endoscopic surgical experience. Each surgeon’s learning curve was plotted using the Cumulative Sum method and divided into three or four phases of technique learning at the turning point of the learning curve. The sociodemographic and clinical features of patients in each phase were then compared and factors potentially associated with operation time were also screened. Results: The learning curve was presented in four phases. The operation time (OT) was significantly shorter in phases II (53.66 ± 16.55 min) and IV (54.39 ± 23.45 min) as compared with phases I (68.74 ± 15.85) and III (75.93 ± 30.55) (p <0.001). More cases of serve pelvic adhesion and chocolate cyst were assigned in the later phases. The presence of pelvic adhesion [adjusted odds ratio (OR) 7.149 (0.506, 13.792), p = 0.035] and bilateral cyst [adjusted OR 16.996 (2.155, 31.837), p = 0.025], max diameter of cyst[adjusted OR 2.799 (0.174, 5.425), p = 0.037], and surgeon’s experience [adjusted OR -6.118 (-11.814, -0.423), p =0.035] were significantly associated with OT. Conclusion: There learning curve of ovarian vNOTES has four phases. vNOTES ovarian cystectomy could be mastered after performing seven, nine, and 16 cases by surgeons with the most, average, and least experience in gynecologic endoscopic surgeries. Trial registration : ChiCTR2200059282 (Registered on April 28th, 2022) transvaginal natural orifice transluminal endoscopic surgery ovarian cystectomy learning curve cumulative sum analysis Figures Figure 1 Figure 2 Figure 3 Background Ovarian cysts reportedly have an occurrence rate of 4–7% among premenopausal women and approximately 20% among postmenopausal women[ 1 , 2 , 3 ]. It has been recommended by the American College of Obstetricians and Gynecologists that simple cysts found in ultrasonographic examinations should be treated conservatively and followed-up safely even in postmenopausal women. However, for symptomatic or non-simple cysts, timely surgical intervention is indicated to avoid rupture and other adverse outcomes. The transvaginal natural orifice transluminal endoscopic surgery (vNOTES) is an emerging minimally invasive surgical (MIS) technique that reportedly has faster postoperative recovery, no visible abdominal skin scar, and easier specimen removal compared with traditional and even transumbilical laparoscopic single site surgery(TU-LESS) [ 4 , 5 , 6 ]. Since the first report of vNOTES ovarian cyst surgery in 2012, multiple clinical studies regarding its application in treating ovarian cysts have shown its non-inferiority to laparoscopy in terms of surgical conversion and postoperative outcomes.[ 4 , 6 ] However, due to factors, including the totally different surgical approaches, opposite operating angles compared to traditional laparoscopy, narrow operating space, and chopstick effect (the instruments interfere with each other due to the narrow operating space in single port endoscopy), many specialists believe that the learning technique for vNOTES might be challenging, and the cost-effectiveness of learning the technique could be low[ 7 , 8 ]. In this study, we presented the learning curve of three gynecologists with different levels of surgical experience in performing laparoendoscopy to evaluate the feasibility of learning the technique. Methods Study design The present study reviewed and analyzed the sociodemographic—age, body mass index (BMI), parity and gravity, previous delivery mode, etc.—and operation-related clinical features—surgical type, surgeons’ experience, pathological type, operation time (OT), estimated intraoperative blood loss, hemoglobin (Hb) decrease, cyst size, etc.—of 127 cases of vNOTES ovarian cystectomy, which were performed between February 2019 and March 2023 by three gynecologic surgeons with different levels of experience of gynecological laparoscopies at Chengdu Women’s and Children’s Central Hospital. We also analyzed the learning curves of each surgeon. Among the three surgeons, the most experienced one is an expert in laparoendoscopy, who has 20 years of experience in gynecology and performed approximately 500 cases of TU-LESS; the youngest surgeon in this study is a new attending physician who has 10 years of working experience and conducted more than 200 cases of TU-LESS; the other gynecologist has 15 years of working experience and successfully performed approximately 300 cases of TU-LESS. Briefly, the most experienced surgeon was designated as surgeon #1; the surgeon with middle-level experience was designated as surgeon #2; and the least experienced surgeon was designated as surgeon #3. Among the clinical characteristics included in the present study, we mainly focused on the OT which reflected the competency of surgeons in performing ovarian vNOTES. We applied the cumulative sum (CUSUM) methodology on the OT to plot the learning curve of each surgeon and divided their vNOTES technique learning process into three or four phases at the turning points of the CUSUM curve, namely the exploration phase (Phase I), competence-acquiring phase (Phase II), challenge phase (Phase III), and proficiency phase (Phase IV, for the most highly experienced surgeon only). In the first and second phases, relatively easier surgeries were assigned. Since Phase III, more technically challenging surgeries, mainly chocolate cystectomy and cases with relatively severe pelvic adhesion were assigned, especially to surgeon #1. The sociodemographic and clinicopathological characteristics of the cases performed in the different phases were also compared subsequently. Patient selection The patients were included based on the following criteria: (1) has ovarian cysts which require surgical intervention; (2) has low possibility of malignancy according to imaging features and tumor markers; (3) shows preference for vNOTES over other surgical options. The patients were excluded based on the following criteria: has never had sexual intercourse; has suspected or confirmed rectovaginal endometriosis; and has confirmed severe pelvic adhesion. Operating procedure of vNOTES ovarian cystectomy This study applied similar surgical methods and equipment as described in previous publications [ 6 , 9 , 10 ]. The detailed surgical procedures were as follows: (1) Patients were placed in the Trendelenburg position and treated under general anesthesia following endotracheal intubation and insertion of Foley catheter for urinary drainage. After disinfection and draping, the cervix and vagina were exposed, especially the posterior fornix, which were disinfected three times. (2) The posterior labium of the cervix was pulled toward the upper and exterior direction using a cervical clamp to expose the posterior fornix of the vagina (Supplementary Figure. 1A) . A 2–2.5-cm long posterior colpotomy incision was made at 0.5 cm below the cervical vaginal junction ( Supplementary Figure. 1B ) to get access to the abdominal cavity after incising the peritoneum (Supplementary Figure. 1C and 1D). (3) A disposable retractor (Figure. 1A) was placed into the abdominal cavity through the posterior culdotomy incision. The surgical platform (Figure. 1B and 1C) was established after establishing the pneumoperitoneum. The conventional laparoendoscopic equipment was applied in the subsequent surgical procedures. (4) The abdominopelvic cavity was then carefully investigated to confirm the location, size, and adjacent organs of the ovarian cysts. Any pelvic adhesion, if existed, would be separated. (5) The cortex of the ovarian cyst was incised using scissor or monopolar electrotome. The cyst was then separated completely between the cyst wall and the rest of the ovarian stroma (Figure. 1D) . (6) The excised cyst was incorporated into the bag, then the excised samples and bag were removed through the vaginal incision. (7) The ovary was sutured using an absorbable suture to stop bleeding and allow for reshaping (Figure. 1E) . (8) Finally, the pelvic cavity was washed with sterile saline at body temperature, followed by the suction of CO 2 , removal of the retractor, and serial suturing of the vaginal incision using a 2/0 absorbable suture line. Learning curve analysis To analyze the changes in the surgeons’ proficiency in performing ovarian vNOTES during the study period, their two-dimensional learning curves were plotted using the following two parameters for each surgeon: X-value, which represents the number of ovarian vNOTES the corresponding surgeon has performed, which were ordered chronologically from the earliest to the latest, and Y-value, which indicates CUSUM OT . The CUSUM OT of each case were calculated using the formula: $$CUSUM OTn={\sum }_{i=1}^{n}\begin{array}{c}\\ \left(\text{x}\text{i}-\mu \right)\\ \end{array}$$ CUSUM OT is the running total of differences between the individual case’s OT and mean OT of all cases. Hence, it could be conducted recursively. The OT of a certain case is designated as xi , and the mean OT of all cases is designated as µ . For instance, the CUSUM OT1 of case no.1 was the difference between the OT for the first case and µ. The CUSUM OTn of case no. n is case no. (n – 1)'s CUSUM OT(n−1) added to the difference between the OT for case no. n and µ. The calculation process was repeated until the final case was calculated, and CUSUM OT final reaches zero[ 9 , 11 ] . Statistical analysis IBM SPSS Statistics for Windows, version 25 (IBM Corp., Armonk, N.Y., USA) and Prism for Window, version 9.0 (GraphPad Software Inc., San Diego, CA, USA) were used for statistical analysis. Categorical variables are presented as numbers and percentages and were analyzed using Chi-squared test or Fisher Exact test when appropriate. As for continuous data, the normally distributed ones are shown as average ± standard deviation and compared using one-way analysis of variance. The non-normally distributed continuous variables are compared using the Kruskal–Wallis test. The learning curves of each surgeon were plotted using the aforementioned CUSUM methods. To screen out the parameters which were significantly associated with the OT, we established a multivariable linear regression model for OT and included all the relevant factors, such as age, BMI, previous pelvic surgery, pelvic adhesion, learning curve phase, estimated blood loss, uni- or bilaterality of cyst(s), occurrence complications, maximum cyst diameter, surgeon experience, parity, and pathologic types (chocolate or non-chocolate cyst). A two-sided p-value lower than 0.05 was considered statistically significant. Results Overall profile of participants Table 1 listed the general sociodemographic and perioperative information of all participants in our study. There were 127 patients with an average age of 35.52 ± 11.32 years and BMI of 21.83 ± 3.12 (kg/m2). The maximum diameter of their ovarian cysts was 5.33 ± 1.79 cm. Approximately 30% had undergone pelvic surgery before vNOTES ovarian cystectomy. Approximately one-quarter (27 cases) experienced cesarean sections, and 51 cases (40.2%) had delivered vaginally. Approximately 30% of patients had pelvic adhesion, among which 22 cases (17.3%) were mild, 9 cases (7.1%) were average, and the remaining 12 cases (9.4%) were complicated with severe pelvic adhesion. Only 4 cases (3.1%) had endometriosis (except ovarian chocolate cysts). Thirteen cases (10.2%) had bilateral cysts. The postoperative pathological diagnosis confirmed that there were 52 cases (40.9%) of teratoma, 39 cases (30.7%) of chocolate cyst, 20 cases (15.7%) of simple cyst, 16 cases (12.6%) of cystadenoma among all the cases. The patients had a postoperative hospitalization of 2.91 ± 0.93 days and intraoperatively lost 62.72 ± 93.93 mL blood. Table 1 Description of the patients' characteristics(N = 127) Variables* Age (year) 35.52 ± 11.32 BMI (kg/m2) 21.83 ± 3.12 Max diameter of cyst (cm) 5.33 ± 1.79 History of pelvic surgery 0 91(71.7) 1 25(19.7) 2 11(8.7) Previous delivery mode Cesarean section 27(21.3) Both 1(0.8) Vaginal delivery 51(40.2) None 48(37.8) Presence of pelvic adhesion None 84(66.1) Mild 22(17.3) Middle 9(7.1) severe 12(9.4) Presence of endometriosis** 4(3.1) Laterality of cyst(s) Unilateral 114(89.8) Bilateral 13(10.2) Postoperative pathological type Teratoma 52(40.9) Cystadenoma 16(12.6) Simple cyst 20(15.7) Chocolate cyst 39(30.7) Postoperative hospitalization 2.91 ± 0.93 Intraoperative blood loss(ml) 62.72 ± 93.93 Postoperative pain score*** Day 0 2.87 ± 0.34 Day 1 2.10 ± 0.72 Day 2 1.26 ± 0.63 Day 3**** 0.70 ± 0.60 Perioperative Infection 3(14.3) Intraoperative complications***** 3(14.3) * presented as Mean ± standard deviation or number of case with percentage ** Ovarian chocolate cysts were not included ***Visual Analogue Scale ****Only 29, 37, 29 and 18 patients in Phase I, II, III, IV were respectively included in the Day 3 VAS analysis due to the discharge of other patients. ***** 1 blood transfusion, 1 Paralytic ileus, 1 pelvic infection. Learning curves of surgeons The line graphs of OT and CUSUM value along individual case’s number (in chronologic order) for each surgeon were plotted in Fig. 2 A and 2 B (surgeon #1), Fig. 2 C and 2 D (surgeon #2), Fig. 2 E and 2 F (surgeon #3). As shown in Fig. 2 A, 2 C and 2 E, their average OT of surgeon #1–3 were 64.44min, 67.35 and 57.17 min relatively. Generally, the surgeons spent longer than average OT in the exploration stage (Phase I) and shorter than average OT in the competency stage (Phase II). Consistently, we noticed that the CUMSUM curve of these three surgeons all presented an upward slope in Phase I and a downward slope in Phase II. A steep climbing trend in Phase I was observed in surgeon #1 ( Fig. 2 B ) , who performed 7 cases in the technique exploration stage (phase I). The surgeon #2 and #3 performed 9 and 16 cases respectively in the initial technique learning stage (Fig. 2 D and 2 F). As the surgeon and surgical team got more familiar with the vNOTES ovarian cystectomy procedure, their operation time started to decrease since the beginning of Phase II and their CUSUM curve also showed a downward slope. Surgeon #1 performed 11 cases (case 8–18) in Phase II; while surgeon #2 and #3 both performed 18 cases (case 10–27) in Phase II. Since Phase III, more technically challenging cases were assigned to these surgeons, especially the most experienced one, making their learning curve regained the upward trend, though some fluctuation could also be observed in the Phase III of surgeon #2 and #3’s CUSUM-Case-number curve. As a result, surgeon #1 conducted 13 cases (case 18–30) in Phase III; while surgeon #2 conducted 11 cases (case 27–37); surgeon #3 performed 10 cases in the challenge phase (case 33–42). As more surgeries performed, a downward slope re-appeared in final stage of surgeon #1’s learning curve, “demarcating” a fourth phase (18 cases, case 31–48), during which surgeon #1 gradually gained surgical proficiency of vNOTES ovarian cystectomy despite higher technical difficulty. Clinical characteristics of cases in the four stages Table 2 shows the comparison of the overall demographic and clinical features of participants in the four phases of vNOTES ovarian cystectomy. The comparisons of their age, BMI, gravidity, parity, delivery mode, previous history of abdominopelvic surgery, uni- or bilaterality of ovarian cysts, estimated intraoperative blood loss, Hb decrease at the 72nd postoperative hours, and postoperative pain score did not show any statistical significance. Meanwhile, we noticed a significantly shorter OT in phase II (53.66 ± 16.55 min) and IV (54.39 ± 23.45 min) as compared with phase I (68.74 ± 15.85) and III (75.93 ± 30.55) (p < 0.001). There were more cases with severe pelvic adhesion in later phases though not statistically significant [0 case in Phase I, 3 (6.4%) cases in Phase II, 4 cases (12.9%) in Phase III, and 5 cases (27.8%) in Phase IV, p = 0.591]. Similarly, there were significantly more cases with endometriosis (3 cases, 16.7%) in phase 4 than in phases I (1 case, 3.2%), II (0 case) and III (0 case) (p = 0.004). Moreover, the maximum cyst diameter significantly increased in later phases, with 4.79 ± 1.39 cm in phase I, 5.11 ± 1.70 cm and 5.93 ± 1.96 cm in Phase III, and 5.78 ± 2.06 cm in phase IV (p = 0.041). Similarly, the incidence of postoperative infection and other complications also increased remarkably in later phases, with 1 case (3.2%) of infection and blood transfusion occurring in phase III and two cases (11.1%) of infection, 1 case of paralytic ileus, and 1 pelvic infection in phase IV. Infection and other complications did not occur in phases I and II (p = 0.047). Table 2 Characteristics and perioperative data of four phases Phase I(N = 31) Phase II(N = 47) Phase III(N = 31) Phase Ⅳ(N = 18) P-value Age (year) 33.58 ± 9.97 36.17 ± 11.31 34.55 ± 7.92 38.83 ± 17.20 0.422 a BMI (kg/m 2 ) 21.44 ± 2.39 21༎62 ± 3.01 22.66 ± 3.65 21.65 ± 3.52 0.408 a Gravidity 0.090 b None 9(29.0) 7(14.9) 11(35.4) 6(33.3) 1 3(9.7) 18(38.3) 10(32.3) 3(16.7) 2 7(22.6) 12(25.5) 5(16.1) 2(11.1) ≥ 3 12(38.7) 10(21.3) 15(48.4) 7(38.9) Parity 0.277 b None 11(35.5) 14(29.8) 16(51.6) 7(38.9) 1 15(48.4) 26(55.3) 13(41.9) 6(33.3) ≥ 2 5(16.1) 7(14.9) 2(6.5) 5(27.8) Delivery mode 0.582 b None 11(35.5) 14(29.8) 16(51.6) 7(38.9) Vaginal delivery 13(41.9) 22(46.8) 9(29.0) 7(38.9) Cesarean section 7(22.6) 11(23.4) 5(16.1) 4(22.2) Both 0 0 1(3.2) 0 History of abdominopelvic surgery 0.738 b None 24(77.4) 31(66.0) 24(77.4) 12(66.7) 1 5(16.1) 12(25.5) 5(16.1) 3(16.7) 2 2(6.5) 4(8.5) 2(6.5) 3(16.7) Presence of pelvic adhesion 0.591 c None 25(80.6) 30(63.8) 18(58.1) 11(61.1) Mild 5(16.2) 1021.3) 6(19.4) 1(3.2) Middle 1(3.2) 4(8.5) 3(9.7) 1(3.2) Severe 0 3(6.4) 4(12.9) 5(27.8) Presence of endometriosis 1(3.2) 0 0 3(16.7) 0.004 c Max diameter of cyst (cm) 4.79 ± 1.39 5.11 ± 1.70 5.93 ± 1.96 5.78 ± 2.06 0.041 a Uni- or bilaterality of ovarian cysts 0.457 c Unilateral 26(83.9) 44(93.6) 27(87.1) 17(94.4) Bilateral 5(16.1) 3(6.4) 4(12.9) 1(5.6) Operation time (min) 68.74 ± 15.85 53.66 ± 16.55 75.93 ± 30.55 54.39 ± 23.45 <0.001 c Estimated blood loss (ml) 44.51 ± 35.58 52.87 ± 53.92 90.97 ± 149.76 71.11 ± 115.40 0.202 c Postoperative hospitalization 2.87 ± 0.67 2༎81 ± 0.97 3.00 ± 0.52 3.11 ± 1.57 0.629 a Postoperative pain score * Day 0 2.90 ± 0.30 2.89 ± 0.31 2.80 ± 0.40 2.83 ± 0.38 0.624 a Day 1 2.16 ± 0.64 2.11 ± 0.73 2.13 ± 0.85 1.94 ± 0.64 0.778 a Day 2 1.35 ± 0.61 1.22 ± 0.66 1.23 ± 0.67 1.28 ± 0.57 0.805 a Day3 ** 0.79 ± 0.56 0.76 ± 0.68 0.59 ± 0.50 0.61 ± 0.60 0.480 a Hb decrease at postoperative 72 h (g/L) 20.71 ± 8.27 19.98 ± 9.00 22.68 ± 9.09 21.78 ± 10.30 0.614 a Perioperative Infection 0 0 1(3.2) 2(11.1) 0.047 c Intraoperative complications 0 0 1(3.2) *** 2(11.1) **** 0.047 c a Average and standard deviation. One-way Analysis of Variance b Number (percentage). Chi-squared Test c Number (percentage). Fisher Exact Test d Average and standard deviation. Kruskal-Wallis Test *Visual Analogue Scale **Only 29, 37, 29 and 18 patients in Phase I, II, III, IV were respectively included in the Day 3 VAS analysis due to the discharge of other patients. ***1 blood transfusion ****1 Paralytic ileus; 1 pelvic infection As shown in Table 3 , among all the 127 cases, there were 31 cases of vNOTES ovarian cystectomies performed in phase I, 47 cases performed in phase II, 37 cases in phase III, and 18 cases in phase IV. We further divided the cases in each phase into four subgroups including the teratoma, cystadenoma, simple cyst, and chocolate cyst according to their pathologic types. The Fisher exact test showed that there were markedly less teratoma (2 cases, 11.1%) and more cholate cysts (10 cases, 55.6%) conducted in phase IV. Conversely, there was an opposite trend in ovarian vNOTES in treating more challenging pathologic types, including chocolate cyst, the percentage of which climbed from 12.9% (4 cases) in phase I to 29.8% (14 cases) and 35.5% (11 cases) in phases II and III, respectively, to 55.6% (10 cases) in phase IV (p = 0.039). Table 3 Description of the pathologic type of four phases Teratoma(N = 52) Cystadenoma(N = 16) Simple cyst(N = 20) Chocolate cyst(N = 39) Phase I (N = 31) 20(64.5) 3(9.7) 4(12.9) 4(12.9) Phase II (N = 47) 17(36.2) 6(12.8) 10(21.3) 14(29.8) Phase III (N = 31) 13(41.9) 4(12.9) 3(9.7) 11(35.5) Phase Ⅳ (N = 18) 2(11.1) 3(16.7) 3(16.7) 10(55.6) P value 0.039 a a Number (percentage). Fisher Exact Test Table 4 presents the OT of vNOTES in treating four different pathologic types of ovarian cysts in four distinct phases. The comparison in OT in treating different pathologic types within each phase did not show any statistical significance. The comparison of OT for specific pathologic types in different phases showed that there was a remarkable decrease in OT in treating teratoma and cystadenoma in the competency phase and a noticeable surge of OT in challenge phase. The mean ± standard deviation of vNOTES in treating teratoma dropped from 70.20 ± 14.81 min in phase I to 46.06 ± 11.33 min in phase II, rebounded to 74.38 ± 33.75 min in phase III, and eventually decreased to 42.40 ± 6.58 min in phase IV (p<0.001). A similar trend was also observed in vNOTES cystadenoma cystectomy, the OT of which decreased from 88.33 ± 14.43 min in phase I to 50.83 ± 9.37 min in phase II and surged again to 69.00 ± 39.56 min in phase III and 71.67 ± 20.82 min in phase IV (p = 0 .040). vNOTES ovarian cystectomies for treating simple cysts had similar average OT in phases I (51.75 ± 3.50 min) and II (55.80 ± 19.46 min), but remarkably longer OT in phase III (69.33 ± 12.90 min) and shorter OT in phase IV (38.00 ± 1.73 min). Such comparison of vNOTES chocolate cystectomy did not reveal any statistical difference, though a longer OT in the 3rd phase (82.09 ± 29.20 min) was observed (p = 0.206). Table 4 Operation time (in minutes) among the four phases stratified by pathologic disease Teratoma (N = 52) Cystadenoma (N = 16) Simple cyst (N = 20) Chocolate cyst (N = 39) P-value Phase I (N = 31) 70.20 ± 14.81 88.33 ± 14.43 51.75 ± 3.50 63.75 ± 12.50 0.134 Phase II (N = 47) 46.06 ± 11.33 50.83 ± 9.37 55.80 ± 19.46 62.57 ± 18.64 0.188 Phase III (N = 31) 74.38 ± 33.75 69.00 ± 39.56 69.33 ± 12.90 82.09 ± 29.20 0.857 Phase Ⅳ (N = 18) 42.40 ± 6.58 71.67 ± 20.82 38.00 ± 1.73 62.57 ± 30.04 0.148 P-value <0.001 0.040 0.013 0.206 a Average and standard deviation. One-way Analysis of Variance Multivariate regression analysis for operation time of vNOTES ovarian cystectomy To further evaluate the potential significant association between OT and other factors, a multivariable linear regression model was established using the aforementioned methods. The results (Fig. 3 ) revealed that there are significant associations between OT and the following variables: (1) presence of pelvic adhesion [adjusted odds ratio (OR) 7.149 (0.506, 13.792), p = 0.035], (2) presence of bilateral cyst [adjusted OR 16.996 (2.155, 31.837), p = 0.025], (3) max diameter of cyst[adjusted OR 2.799 (0.174, 5.425), p = 0.037], and (4) surgeon’s experience [adjusted OR -6.118 (-11.814, -0.423), p = 0.035]. Discussion vNOTES is quite different from LESS and conventional laparoendoscopic surgery in multiple aspects. The establishment of a surgical path might be the most challenging one, due to the risks of injuring neighboring organs, including the rectum and urinary bladder [ 12 , 13 ]. More than 1,000 cases of ovarian vNOTES were conducted in our institute between December 2018 and October 2022 which were all performed through culdotomy in the posterior vaginal fornix[ 10 ]. After the initial technical exploration via approximately 30 cases of tentative vNOTES operation by two experts with more than 2 decades of experience in vaginal and laparoendoscopic surgeries, we established a standard operating procedure for conducting vNOTES and achieved better surgical outcomes and cosmetic satisfaction, faster recovery, and reduced postoperative pain compared with LESS or conventional laparoendoscopy[ 6 , 9 ]. In this Standard Operating Procedure (SOP), we divested the cyst in the same manner as in LESS cystectomy after establishing the surgical platform. Our clinical practice of ovarian-vNOTES also supported the viewpoint that vNOTES is easier to perform compared to LESS because of the closer proximity to the ovaries via the culdotomy entrance, less severe chopstick effects, and easier specimen removal[ 12 ] . According to the international consensus of vNOTES experts, beginners should start from learning complete hysterectomy via vNOTES since the surgical path established therefrom would be much easier to access than the culdotomy in the posterior or anterior vaginal fornix[ 14 ]. Others state that vNOTES has a long learning process and may be quite challenging in inexperienced hands[ 13 ]. However, in our department, we observed that ovarian cystectomy via vNOTES is much more frequently conducted even by less experienced hands due to the high incidence of ovarian and tubal diseases. Moreover, posterior vaginal fornix culdotomy is the dominantly preferred entrance for vNOTES surgery. Through a reasonably designed learning process (performing technically difficult cases in later stage or assigning them to experienced hands), our data showed that, even without experiencing vNOTES hysterectomy, surgeons with different levels of experience in performing laparoendoscopy could also master ovarian cystectomy via vNOTES in relatively less cases. The experienced surgeons only needed seven and nine cases, respectively, in the technique-acquiring phase, while the least experienced surgeons performed only 16 cases to reach competency, which supported the feasibility and promising prospect of promoting ovarian vNOTES. For young surgeons lacking experiences in conducting vaginal surgeries, they could also complete ovarian cystectomy via vNOTES after standardized training. Our study assigned relatively diverse pathologic types in the surgeons’ different learning phases, among which the chocolate cyst almost takes up one-third of the total cases. Some previous studies reported that endometriosis might cause adhesion in the pouch of Douglas, and that vNOTES ovarian cystectomy of chocolate cysts should be avoided.[ 15 ] Probably due to this reason, very limited cases of vNOTES endometriotic cystectomy has been reported[ 12 ]. Moreover, a previous study of the learning curve of adnexal vNOTES did not include chocolate cysts[ 16 ]. In our study, we noticed that vNOTES may still be used to treat ovarian endometrioma with detailed preoperative examination and assessment to exclude cases with severe adhesion in the pouch of Douglas since it was not significantly related to the OT and surgical conversion did not occur; however, several cases of endometriosis and severe pelvic adhesion were included. To date, there are many studies on the learning curve of vNOTES hysterectomy, while that of vNOTES ovarian cystectomy or adnexectomy was only reported once by Huang et al [ 9 , 11 , 16 , 17 ]. Compared with their study, our study had a similar cohort size but included more surgeons with different levels of gynecologic endoscopy experience. Moreover, we divided the learning curves into more stages, which could be a better reference for more surgeons. We also noticed that the mass diameter in their study was not significantly associated with the OT. In our study, cyst size and bilaterality are both positively associated with the OT, which might be caused by the different pathologic types included in our study. Another mismatch between our studies was that they did not find any cut-off point for determining the volume of cases needed to achieve mastery of adnexal vNOTES. Conversely, we noticed that seven to 16 cases were enough for initial technique establishment. This might also be explained by the various pathologic and surgeon types included in our study, given that all the cases were conducted by a single high-volume surgeon in their study. Nevertheless, our results both suggested that it might be more appropriate to start learning the vNOTES technique from ovarian or adnexal vNOTES, and less cases are needed to learn the technique and achieve proficiency than the vNOTES hysterectomy. There are also several limitations in present study. Firstly, the surgeons who performed the vNOTES ovarian surgeries in our study may have performed more laparoscopic surgeries than many other less populous regions and countries, which may impair the generality of our findings. Secondly, the preoperative assessment of surgical difficulty was mainly made by subjective standards rather than standardized stratification or scoring system, which, to some extent, may hinder the assignment of surgeries to different surgeons and phases. Conclusions Our learning curve analysis of ovarian vNOTES depicted four specific stages. vNOTES for ovarian cystectomy could be mastered after performing seven, nine, and 16 cases by surgeons with different endoscopic surgical experience. The presence of pelvic adhesion or bilateral cyst and cyst size were positively related to OT, while the surgeon’s experience was negatively correlated to OT. Abbreviations vNOTES: transvaginal natural orifice transluminal endoscopic surgery MIS: minimally invasive surgery TU-LESS: transumbilical laparoscopic single site surgery OT: operation time BMI: body mass index CUSUM: cumulative sum Hb:hemoglobin Declarations Ethics approval and consent to participate This study was approved by the ethics committee of Chengdu Women's and Children's Central Hospital [No.WCCH-B2021(39)]. Before the surgery, All patients were well-informed of the potential risks and advantages of vNOTES and other alternative surgical treatments, including TU-LESS or multi-port laparoscopy, and expressed their preference for vNOTES. Written informed consent was obtained from all the participants during the preoperative consultation. All identifiable private information were deleted or not transcribed while extracting the patients’ pathological and clinical characteristics from the Hospital Information System to protect patients’ privacy. Consent for publication Not applicable. Availability of data and materials Data supporting the conclusion are provided within the manuscript or supplementary information files. The original data are available from the corresponding authors upon reasonable request. Competing interests The authors declare no conflict of interest. Funding Chengdu High-level Key Clinical Specialty Construction Project, Chengdu Municipal Health Commission Project (Grant number:2021215), Fifth Round of Chengdu Municipal Science and Technology Research Program (Grant number:2021-YF05-00627-SN), Chengdu Municipal Medical Research Project in 2023 (Grant number:2023352), and Japan China Sasakawa Medical Fellowship Program(Grant number:4408). Author contribution This study was designed by Dan Feng, Tianjiao Liu, and Xin Li. Dan Feng and Lu Huang completed the data collection. Tianjiao Liu, Dan Feng, and Xin Li drafted this manuscript. Tianjiao Liu and Xin Li performed the statistical analysis. Li Xiao, Li He and Yonghong Lin supervised this project and critically reviewed this manuscript. All authors participated in the revision of the manuscript. Acknowledgements We thank Dr.Qiannan Hou for performing the vNOTES ovarian cystectomies. We also feel grateful for the participation of all the patients. References Borgfeldt C, Andolf E. Transvaginal sonographic ovarian findings in a random sample of women 25–40 years old. Ultrasound Obstet Gynecol. 1999;13(5):345–50. Bottomley C, Bourne T. Diagnosis and management of ovarian cyst accidents. Best Pract Res Clin Obstet Gynaecol. 2009;23(5):711–24. 10.1016/j.bpobgyn.2009.02.001 . Sadowski EA, Paroder V, Patel-Lippmann K, et al. Indeterminate Adnexal Cysts at US: Prevalence and Characteristics of Ovarian Cancer. Radiology. 2018;287(3):1041–9. 10.1148/radiol.2018172271 . Zhang C, Duan K, Fang F, et al. Comparison of Transvaginal and Transumbilical Laparoscopic Single-Site Surgery for Ovarian Cysts. JSLS. 2021;25(2). 10.4293/JSLS.2021.00019 . Housmans S, Noori N, Kapurubandara S, et al. Systematic Review and Meta-Analysis on Hysterectomy by Vaginal Natural Orifice Transluminal Endoscopic Surgery (vNOTES) Compared to Laparoscopic Hysterectomy for Benign Indications. J Clin Med. 2020;9(12). 10.3390/jcm9123959 . Huang L, Lin Y-H, Yang Y, et al. Comparative analysis of vaginal natural orifice transluminal endoscopic surgery versus transumbilical laparoendoscopic single-site surgery in ovarian cystectomy. J Obstet Gynaecol Res. 2021;47(2):757–64. 10.1111/jog.14603 . Yoshiki N. Review of transvaginal natural orifice transluminal endoscopic surgery in gynecology. Gynecol Minim Invasive Ther. 2017;6(1):1–5. 10.1016/j.gmit.2016.11.007 . Li C-B, Hua K-Q. Transvaginal natural orifice transluminal endoscopic surgery (vNOTES) in gynecologic surgeries: A systematic review. Asian J Surg. 2020;43(1):44–51. 10.1016/j.asjsur.2019.07.014 . Huang L, He L, Huang L, et al. Learning curve analysis of transvaginal natural orifice transluminal endoscopic hysterectomy combined under the standard operating procedure. Int J Gynaecol Obstet. 2022;159(3):689–95. 10.1002/ijgo.14238 . Huang L, Feng D, Gu D-X, et al. Transvaginal natural orifice transluminal endoscopic surgery in gynecological procedure: Experience of a Women's and Children's Medical Center from China. J Obstet Gynaecol Res. 2022;48(11):2926–34. 10.1111/jog.15402 . Park JS, Ahn HK, Na J, et al. Cumulative sum analysis of learning curve for video-assisted mini-laparotomy partial nephrectomy in renal cell carcinoma. Med (Baltim). 2019;98(17):e15367. 10.1097/MD.0000000000015367 . Li Y-C, Ku F-C, Kuo H-H, et al. Transvaginal endoscopic surgery-assisted versus conventional laparoscopic adnexectomy (TVEA vs. CLA): A propensity-matched study and literature review. Taiwan J Obstet Gynecol. 2017;56(3):336–41. 10.1016/j.tjog.2017.04.013 . Brandão P, Almeida A, Ramôa P. vNOTES for adnexal procedures. J Obstet Gynaecol. 2021;41(7):1134–8. 10.1080/01443615.2020.1841124 . Kapurubandara S, Lowenstein L, Salvay H, et al. Consensus on safe implementation of vaginal natural orifice transluminal endoscopic surgery (vNOTES). Eur J Obstet Gynecol Reprod Biol. 2021;263:216–22. 10.1016/j.ejogrb.2021.06.019 . Wang C-J, Wu P-Y, Kuo H-H, et al. Natural orifice transluminal endoscopic surgery-assisted versus laparoscopic ovarian cystectomy (NAOC vs. LOC): a case-matched study. Surg Endosc. 2016;30(3):1227–34. 10.1007/s00464-015-4315-6 . Huang Y-T, Yang L-Y, Pan Y-B, et al. Learning Curve Analysis of Transvaginal Natural Orifice Adnexal Surgery. J Minim Invasive Gynecol. 2020;27(2):489–97. 10.1016/j.jmig.2019.04.009 . Lauterbach R, Matanes E, Amit A, et al. Transvaginal Natural Orifice Transluminal Endoscopic (vNOTES) Hysterectomy Learning Curve: Feasibility in the Hands of Skilled Gynecologists. Isr Med Assoc J. 2020;22(1):13–6. Additional Declarations No competing interests reported. Supplementary Files Supplementarymaterial.doc Cite Share Download PDF Status: Published Journal Publication published 25 Jul, 2024 Read the published version in BMC Women's Health → Version 1 posted Editorial decision: Revision requested 03 Jun, 2024 Reviews received at journal 12 May, 2024 Reviewers agreed at journal 02 May, 2024 Reviews received at journal 24 Apr, 2024 Reviewers agreed at journal 10 Apr, 2024 Reviewers invited by journal 09 Apr, 2024 Editor invited by journal 27 Mar, 2024 Submission checks completed at journal 25 Mar, 2024 Editor assigned by journal 25 Mar, 2024 First submitted to journal 22 Mar, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4152484","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":283397944,"identity":"c26d1c24-edba-4913-ae04-0a19d965c21a","order_by":0,"name":"Dan Feng","email":"","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Dan","middleName":"","lastName":"Feng","suffix":""},{"id":283397945,"identity":"7a7fc0d5-08fd-473f-bf74-5e104aff46a4","order_by":1,"name":"Tianjiao Liu","email":"","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Tianjiao","middleName":"","lastName":"Liu","suffix":""},{"id":283397946,"identity":"49079900-5083-42b0-b934-5c78a9e675fe","order_by":2,"name":"Li Xiao","email":"","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Xiao","suffix":""},{"id":283397947,"identity":"f5724381-3615-42e2-8a30-c47d36ae830e","order_by":3,"name":"Xin Li","email":"","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Xin","middleName":"","lastName":"Li","suffix":""},{"id":283397948,"identity":"1dc13196-ac90-4680-a9f6-6e8cb5ab6b10","order_by":4,"name":"Lu Huang","email":"","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Lu","middleName":"","lastName":"Huang","suffix":""},{"id":283397949,"identity":"150979b9-f9be-45e9-9c78-21a76735629c","order_by":5,"name":"Li He","email":"","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"He","suffix":""},{"id":283397950,"identity":"38cb26a5-9252-4e24-95c7-b10a0bba3cea","order_by":6,"name":"Yonghong Lin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYBACPmYGBhCSY2NmbHyQUFFDWAsbVIsxPztzs8GDM8eI0MIA0ZI4s5+9TfJhCzMRWth5j0kX1FgzbjjM2FaR2MDGwN/enUDAYXxp0jOOpTMbALXcSNwhwyBx5uwGAlp4zKR5Gw6zQbScYWMwkMglTgsPSEtBYhsz8VokJJsZ2xiI1WJszXMs3YCfmbFZIuHMMR6CfuHnP2N4m6fGur6N//jDjz8qauT423vxawECFglkHg8h5SDA/IEYVaNgFIyCUTCCAQCx3D2VmcjyOwAAAABJRU5ErkJggg==","orcid":"","institution":"Chengdu Women’s and Children’s Central Hospital, University of Electronic Science and Technology of China","correspondingAuthor":true,"prefix":"","firstName":"Yonghong","middleName":"","lastName":"Lin","suffix":""}],"badges":[],"createdAt":"2024-03-23 02:44:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4152484/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4152484/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12905-024-03261-2","type":"published","date":"2024-07-25T16:16:07+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":53674197,"identity":"7ec783fa-965e-40be-a529-72b148854622","added_by":"auto","created_at":"2024-03-28 18:27:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1879633,"visible":true,"origin":"","legend":"\u003cp\u003eKey surgical steps of vNOTES ovarian cystectomy\u003c/p\u003e\n\u003cp\u003e(A) disposable retractor\u003c/p\u003e\n\u003cp\u003e(B) insertion of the disposable retractor\u003c/p\u003e\n\u003cp\u003e(C) establishment of the surgical platform\u003c/p\u003e\n\u003cp\u003e(D) divesting the ovarian cyst wall\u003c/p\u003e\n\u003cp\u003e(E) suture and reshaping of the ovary\u003c/p\u003e","description":"","filename":"Figure1surgicalprocedures.png","url":"https://assets-eu.researchsquare.com/files/rs-4152484/v1/1cf24f12a4e03a726641d8bf.png"},{"id":53674199,"identity":"51d09360-ba42-4ae9-9adc-08649e2e30fc","added_by":"auto","created_at":"2024-03-28 18:27:54","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1340634,"visible":true,"origin":"","legend":"\u003cp\u003eLearning curve analysis of vNOTES ovarian cystectomy performed by 3 surgeons\u003c/p\u003e\n\u003cp\u003e(A) The line graphs of OT-Case-number of surgeon #1;\u003c/p\u003e\n\u003cp\u003e(B) The CUSUM-Case-number curve of surgeon #1;\u003c/p\u003e\n\u003cp\u003e(C) The line graph of OT-Case-number of surgeon #2;\u003c/p\u003e\n\u003cp\u003e(D) The CUSUM-Case-number curve of surgeon #2;\u003c/p\u003e\n\u003cp\u003e(E) The line graph of OT-Case-number of surgeon #3;\u003c/p\u003e\n\u003cp\u003e(F) The CUSUM-Case-number curve of surgeon #3;\u003c/p\u003e","description":"","filename":"Figure2Learningcurve.png","url":"https://assets-eu.researchsquare.com/files/rs-4152484/v1/6ed72acefc59ea0affb8ee69.png"},{"id":53674196,"identity":"6e6a407d-08c3-41a5-848b-9afcf25fc86d","added_by":"auto","created_at":"2024-03-28 18:27:53","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":210025,"visible":true,"origin":"","legend":"\u003cp\u003eMultivariate regression analysis for operation time of vNOTES ovarian cystectomy\u003c/p\u003e","description":"","filename":"Figure3Multivariateregressionanalysis.png","url":"https://assets-eu.researchsquare.com/files/rs-4152484/v1/7d11325b67f458ed07b820b5.png"},{"id":61596461,"identity":"7ae0871f-7fdf-49d6-a087-677b69d14216","added_by":"auto","created_at":"2024-08-01 17:27:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5286576,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4152484/v1/dfb9d345-4317-405c-a997-9c576f911424.pdf"},{"id":53674198,"identity":"d8ffe25f-2fab-49e1-8534-e73bb26f79ca","added_by":"auto","created_at":"2024-03-28 18:27:53","extension":"doc","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":3531264,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.doc","url":"https://assets-eu.researchsquare.com/files/rs-4152484/v1/0031dd194a6d44c8e27b04bd.doc"}],"financialInterests":"No competing interests reported.","formattedTitle":"Learning Curve Analysis of Transvaginal Natural Orifice Transluminal Endoscopic Surgery in Treating Ovarian Cysts: A Retrospective Cohort Study","fulltext":[{"header":"Background","content":"\u003cp\u003eOvarian cysts reportedly have an occurrence rate of 4\u0026ndash;7% among premenopausal women and approximately 20% among postmenopausal women[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. It has been recommended by the American College of Obstetricians and Gynecologists that simple cysts found in ultrasonographic examinations should be treated conservatively and followed-up safely even in postmenopausal women. However, for symptomatic or non-simple cysts, timely surgical intervention is indicated to avoid rupture and other adverse outcomes.\u003c/p\u003e \u003cp\u003eThe transvaginal natural orifice transluminal endoscopic surgery (vNOTES) is an emerging minimally invasive surgical (MIS) technique that reportedly has faster postoperative recovery, no visible abdominal skin scar, and easier specimen removal compared with traditional and even transumbilical laparoscopic single site surgery(TU-LESS) [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Since the first report of vNOTES ovarian cyst surgery in 2012, multiple clinical studies regarding its application in treating ovarian cysts have shown its non-inferiority to laparoscopy in terms of surgical conversion and postoperative outcomes.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eHowever, due to factors, including the totally different surgical approaches, opposite operating angles compared to traditional laparoscopy, narrow operating space, and chopstick effect (the instruments interfere with each other due to the narrow operating space in single port endoscopy), many specialists believe that the learning technique for vNOTES might be challenging, and the cost-effectiveness of learning the technique could be low[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In this study, we presented the learning curve of three gynecologists with different levels of surgical experience in performing laparoendoscopy to evaluate the feasibility of learning the technique.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design\u003c/h2\u003e \u003cp\u003e The present study reviewed and analyzed the sociodemographic\u0026mdash;age, body mass index (BMI), parity and gravity, previous delivery mode, etc.\u0026mdash;and operation-related clinical features\u0026mdash;surgical type, surgeons\u0026rsquo; experience, pathological type, operation time (OT), estimated intraoperative blood loss, hemoglobin (Hb) decrease, cyst size, etc.\u0026mdash;of 127 cases of vNOTES ovarian cystectomy, which were performed between February 2019 and March 2023 by three gynecologic surgeons with different levels of experience of gynecological laparoscopies at Chengdu Women\u0026rsquo;s and Children\u0026rsquo;s Central Hospital. We also analyzed the learning curves of each surgeon. Among the three surgeons, the most experienced one is an expert in laparoendoscopy, who has 20 years of experience in gynecology and performed approximately 500 cases of TU-LESS; the youngest surgeon in this study is a new attending physician who has 10 years of working experience and conducted more than 200 cases of TU-LESS; the other gynecologist has 15 years of working experience and successfully performed approximately 300 cases of TU-LESS. Briefly, the most experienced surgeon was designated as surgeon #1; the surgeon with middle-level experience was designated as surgeon #2; and the least experienced surgeon was designated as surgeon #3. Among the clinical characteristics included in the present study, we mainly focused on the OT which reflected the competency of surgeons in performing ovarian vNOTES. We applied the cumulative sum (CUSUM) methodology on the OT to plot the learning curve of each surgeon and divided their vNOTES technique learning process into three or four phases at the turning points of the CUSUM curve, namely the exploration phase (Phase I), competence-acquiring phase (Phase II), challenge phase (Phase III), and proficiency phase (Phase IV, for the most highly experienced surgeon only). In the first and second phases, relatively easier surgeries were assigned. Since Phase III, more technically challenging surgeries, mainly chocolate cystectomy and cases with relatively severe pelvic adhesion were assigned, especially to surgeon #1. The sociodemographic and clinicopathological characteristics of the cases performed in the different phases were also compared subsequently.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003ePatient selection\u003c/h2\u003e \u003cp\u003eThe patients were included based on the following criteria:\u003c/p\u003e \u003cp\u003e(1) has ovarian cysts which require surgical intervention;\u003c/p\u003e \u003cp\u003e(2) has low possibility of malignancy according to imaging features and tumor markers;\u003c/p\u003e \u003cp\u003e(3) shows preference for vNOTES over other surgical options.\u003c/p\u003e \u003cp\u003eThe patients were excluded based on the following criteria:\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ehas never had sexual intercourse;\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ehas suspected or confirmed rectovaginal endometriosis; and\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ehas confirmed severe pelvic adhesion.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eOperating procedure of vNOTES ovarian cystectomy\u003c/h2\u003e \u003cp\u003eThis study applied similar surgical methods and equipment as described in previous publications [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The detailed surgical procedures were as follows:\u003c/p\u003e \u003cp\u003e(1) Patients were placed in the Trendelenburg position and treated under general anesthesia following endotracheal intubation and insertion of Foley catheter for urinary drainage. After disinfection and draping, the cervix and vagina were exposed, especially the posterior fornix, which were disinfected three times.\u003c/p\u003e \u003cp\u003e(2) The posterior labium of the cervix was pulled toward the upper and exterior direction using a cervical clamp to expose the posterior fornix of the vagina \u003cb\u003e(Supplementary Figure. 1A)\u003c/b\u003e. A 2\u0026ndash;2.5-cm long posterior colpotomy incision was made at 0.5 cm below the cervical vaginal junction (\u003cb\u003eSupplementary Figure. 1B\u003c/b\u003e) to get access to the abdominal cavity after incising the peritoneum \u003cb\u003e(Supplementary Figure. 1C and 1D).\u003c/b\u003e\u003c/p\u003e \u003cp\u003e(3) A disposable retractor \u003cb\u003e(Figure. 1A)\u003c/b\u003e was placed into the abdominal cavity through the posterior culdotomy incision. The surgical platform \u003cb\u003e(Figure. 1B and 1C)\u003c/b\u003e was established after establishing the pneumoperitoneum. The conventional laparoendoscopic equipment was applied in the subsequent surgical procedures.\u003c/p\u003e \u003cp\u003e(4) The abdominopelvic cavity was then carefully investigated to confirm the location, size, and adjacent organs of the ovarian cysts. Any pelvic adhesion, if existed, would be separated.\u003c/p\u003e \u003cp\u003e(5) The cortex of the ovarian cyst was incised using scissor or monopolar electrotome. The cyst was then separated completely between the cyst wall and the rest of the ovarian stroma \u003cb\u003e(Figure. 1D)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e(6) The excised cyst was incorporated into the bag, then the excised samples and bag were removed through the vaginal incision.\u003c/p\u003e \u003cp\u003e(7) The ovary was sutured using an absorbable suture to stop bleeding and allow for reshaping \u003cb\u003e(Figure. 1E)\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e(8) Finally, the pelvic cavity was washed with sterile saline at body temperature, followed by the suction of CO\u003csub\u003e2\u003c/sub\u003e, removal of the retractor, and serial suturing of the vaginal incision using a 2/0 absorbable suture line.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eLearning curve analysis\u003c/h2\u003e \u003cp\u003eTo analyze the changes in the surgeons\u0026rsquo; proficiency in performing ovarian vNOTES during the study period, their two-dimensional learning curves were plotted using the following two parameters for each surgeon: X-value, which represents the number of ovarian vNOTES the corresponding surgeon has performed, which were ordered chronologically from the earliest to the latest, and Y-value, which indicates CUSUM\u003csub\u003eOT\u003c/sub\u003e. The CUSUM\u003csub\u003eOT\u003c/sub\u003e of each case were calculated using the formula:\u003cdiv id=\"Equa\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equa\" name=\"EquationSource\"\u003e\n$$CUSUM OTn={\\sum }_{i=1}^{n}\\begin{array}{c}\\\\ \\left(\\text{x}\\text{i}-\\mu \\right)\\\\ \\end{array}$$\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eCUSUM\u003csub\u003eOT\u003c/sub\u003e is the running total of differences between the individual case\u0026rsquo;s OT and mean OT of all cases. Hence, it could be conducted recursively. The OT of a certain case is designated as \u003cem\u003exi\u003c/em\u003e, and the mean OT of all cases is designated as \u003cem\u003e\u0026micro;\u003c/em\u003e. For instance, the CUSUM\u003csub\u003eOT1\u003c/sub\u003e of case no.1 was the difference between the OT for the first case and \u0026micro;. The CUSUM\u003csub\u003eOTn\u003c/sub\u003e of case no. n is case no. (n \u0026ndash; 1)'s CUSUM\u003csub\u003eOT(n\u0026minus;1)\u003c/sub\u003e added to the difference between the OT for case no. n and \u0026micro;. The calculation process was repeated until the final case was calculated, and CUSUM\u003csub\u003eOT final\u003c/sub\u003e reaches zero[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] .\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eIBM SPSS Statistics for Windows, version 25 (IBM Corp., Armonk, N.Y., USA) and Prism for Window, version 9.0 (GraphPad Software Inc., San Diego, CA, USA) were used for statistical analysis. Categorical variables are presented as numbers and percentages and were analyzed using Chi-squared test or Fisher Exact test when appropriate. As for continuous data, the normally distributed ones are shown as average\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation and compared using one-way analysis of variance. The non-normally distributed continuous variables are compared using the Kruskal\u0026ndash;Wallis test. The learning curves of each surgeon were plotted using the aforementioned CUSUM methods. To screen out the parameters which were significantly associated with the OT, we established a multivariable linear regression model for OT and included all the relevant factors, such as age, BMI, previous pelvic surgery, pelvic adhesion, learning curve phase, estimated blood loss, uni- or bilaterality of cyst(s), occurrence complications, maximum cyst diameter, surgeon experience, parity, and pathologic types (chocolate or non-chocolate cyst). A two-sided p-value lower than 0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eOverall profile of participants\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e listed the general sociodemographic and perioperative information of all participants in our study. There were 127 patients with an average age of 35.52\u0026thinsp;\u0026plusmn;\u0026thinsp;11.32 years and BMI of 21.83\u0026thinsp;\u0026plusmn;\u0026thinsp;3.12 (kg/m2). The maximum diameter of their ovarian cysts was 5.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.79 cm. Approximately 30% had undergone pelvic surgery before vNOTES ovarian cystectomy. Approximately one-quarter (27 cases) experienced cesarean sections, and 51 cases (40.2%) had delivered vaginally. Approximately 30% of patients had pelvic adhesion, among which 22 cases (17.3%) were mild, 9 cases (7.1%) were average, and the remaining 12 cases (9.4%) were complicated with severe pelvic adhesion. Only 4 cases (3.1%) had endometriosis (except ovarian chocolate cysts). Thirteen cases (10.2%) had bilateral cysts. The postoperative pathological diagnosis confirmed that there were 52 cases (40.9%) of teratoma, 39 cases (30.7%) of chocolate cyst, 20 cases (15.7%) of simple cyst, 16 cases (12.6%) of cystadenoma among all the cases. The patients had a postoperative hospitalization of 2.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.93 days and intraoperatively lost 62.72\u0026thinsp;\u0026plusmn;\u0026thinsp;93.93 mL blood.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDescription of the patients' characteristics(N\u0026thinsp;=\u0026thinsp;127)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (year)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35.52\u0026thinsp;\u0026plusmn;\u0026thinsp;11.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21.83\u0026thinsp;\u0026plusmn;\u0026thinsp;3.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMax diameter of cyst (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.33\u0026thinsp;\u0026plusmn;\u0026thinsp;1.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistory of pelvic surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e91(71.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25(19.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(8.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrevious delivery mode\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCesarean section\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27(21.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBoth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1(0.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVaginal delivery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e51(40.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48(37.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePresence of pelvic adhesion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e84(66.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22(17.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMiddle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9(7.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003esevere\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12(9.4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePresence of endometriosis**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4(3.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLaterality of cyst(s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnilateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e114(89.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBilateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13(10.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative pathological type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTeratoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52(40.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCystadenoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16(12.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSimple cyst\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20(15.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChocolate cyst\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e39(30.7)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative hospitalization\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntraoperative blood loss(ml)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62.72\u0026thinsp;\u0026plusmn;\u0026thinsp;93.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative pain score***\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.10\u0026thinsp;\u0026plusmn;\u0026thinsp;0.72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.63\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 3****\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;0.60\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePerioperative Infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntraoperative complications*****\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3(14.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e* presented as Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation or number of case with percentage\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e** Ovarian chocolate cysts were not included\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e***Visual Analogue Scale\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e****Only 29, 37, 29 and 18 patients in Phase I, II, III, IV were respectively included in the Day 3 VAS analysis due to the discharge of other patients.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003e***** 1 blood transfusion, 1 Paralytic ileus, 1 pelvic infection.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eLearning curves of surgeons\u003c/h2\u003e \u003cp\u003eThe line graphs of OT and CUSUM value along individual case\u0026rsquo;s number (in chronologic order) for each surgeon were plotted in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB (surgeon #1), Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD (surgeon #2), Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eF (surgeon #3). As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eE, their average OT of surgeon #1\u0026ndash;3 were 64.44min, 67.35 and 57.17 min relatively. Generally, the surgeons spent longer than average OT in the exploration stage (Phase I) and shorter than average OT in the competency stage (Phase II). Consistently, we noticed that the CUMSUM curve of these three surgeons all presented an upward slope in Phase I and a downward slope in Phase II. A steep climbing trend in Phase I was observed in surgeon #1 \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB\u003cb\u003e)\u003c/b\u003e, who performed 7 cases in the technique exploration stage (phase I). The surgeon #2 and #3 performed 9 and 16 cases respectively in the initial technique learning stage (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eD and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eF). As the surgeon and surgical team got more familiar with the vNOTES ovarian cystectomy procedure, their operation time started to decrease since the beginning of Phase II and their CUSUM curve also showed a downward slope. Surgeon #1 performed 11 cases (case 8\u0026ndash;18) in Phase II; while surgeon #2 and #3 both performed 18 cases (case 10\u0026ndash;27) in Phase II. Since Phase III, more technically challenging cases were assigned to these surgeons, especially the most experienced one, making their learning curve regained the upward trend, though some fluctuation could also be observed in the Phase III of surgeon #2 and #3\u0026rsquo;s CUSUM-Case-number curve. As a result, surgeon #1 conducted 13 cases (case 18\u0026ndash;30) in Phase III; while surgeon #2 conducted 11 cases (case 27\u0026ndash;37); surgeon #3 performed 10 cases in the challenge phase (case 33\u0026ndash;42). As more surgeries performed, a downward slope re-appeared in final stage of surgeon #1\u0026rsquo;s learning curve, \u0026ldquo;demarcating\u0026rdquo; a fourth phase (18 cases, case 31\u0026ndash;48), during which surgeon #1 gradually gained surgical proficiency of vNOTES ovarian cystectomy despite higher technical difficulty.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eClinical characteristics of cases in the four stages\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the comparison of the overall demographic and clinical features of participants in the four phases of vNOTES ovarian cystectomy. The comparisons of their age, BMI, gravidity, parity, delivery mode, previous history of abdominopelvic surgery, uni- or bilaterality of ovarian cysts, estimated intraoperative blood loss, Hb decrease at the 72nd postoperative hours, and postoperative pain score did not show any statistical significance. Meanwhile, we noticed a significantly shorter OT in phase II (53.66\u0026thinsp;\u0026plusmn;\u0026thinsp;16.55 min) and IV (54.39\u0026thinsp;\u0026plusmn;\u0026thinsp;23.45 min) as compared with phase I (68.74\u0026thinsp;\u0026plusmn;\u0026thinsp;15.85) and III (75.93\u0026thinsp;\u0026plusmn;\u0026thinsp;30.55) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There were more cases with severe pelvic adhesion in later phases though not statistically significant [0 case in Phase I, 3 (6.4%) cases in Phase II, 4 cases (12.9%) in Phase III, and 5 cases (27.8%) in Phase IV, p\u0026thinsp;=\u0026thinsp;0.591]. Similarly, there were significantly more cases with endometriosis (3 cases, 16.7%) in phase 4 than in phases I (1 case, 3.2%), II (0 case) and III (0 case) (p\u0026thinsp;=\u0026thinsp;0.004). Moreover, the maximum cyst diameter significantly increased in later phases, with 4.79\u0026thinsp;\u0026plusmn;\u0026thinsp;1.39 cm in phase I, 5.11\u0026thinsp;\u0026plusmn;\u0026thinsp;1.70 cm and 5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96 cm in Phase III, and 5.78\u0026thinsp;\u0026plusmn;\u0026thinsp;2.06 cm in phase IV (p\u0026thinsp;=\u0026thinsp;0.041). Similarly, the incidence of postoperative infection and other complications also increased remarkably in later phases, with 1 case (3.2%) of infection and blood transfusion occurring in phase III and two cases (11.1%) of infection, 1 case of paralytic ileus, and 1 pelvic infection in phase IV. Infection and other complications did not occur in phases I and II (p\u0026thinsp;=\u0026thinsp;0.047).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics and perioperative data of four phases\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePhase I(N\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePhase II(N\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePhase III(N\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePhase Ⅳ(N\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (year)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.58\u0026thinsp;\u0026plusmn;\u0026thinsp;9.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36.17\u0026thinsp;\u0026plusmn;\u0026thinsp;11.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34.55\u0026thinsp;\u0026plusmn;\u0026thinsp;7.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e38.83\u0026thinsp;\u0026plusmn;\u0026thinsp;17.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.422\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21.44\u0026thinsp;\u0026plusmn;\u0026thinsp;2.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21༎62\u0026thinsp;\u0026plusmn;\u0026thinsp;3.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.66\u0026thinsp;\u0026plusmn;\u0026thinsp;3.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21.65\u0026thinsp;\u0026plusmn;\u0026thinsp;3.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.408\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGravidity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.090\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9(29.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7(14.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11(35.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3(9.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18(38.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10(32.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7(22.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12(25.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12(38.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10(21.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15(48.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(38.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.277\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(35.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14(29.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16(51.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(38.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15(48.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26(55.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13(41.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6(33.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7(14.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2(6.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5(27.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDelivery mode\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.582\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11(35.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14(29.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16(51.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(38.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVaginal delivery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13(41.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22(46.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9(29.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7(38.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCesarean section\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7(22.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11(23.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4(22.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBoth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistory of abdominopelvic surgery\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.738\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24(77.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31(66.0)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24(77.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12(66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12(25.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2(6.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4(8.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2(6.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePresence of pelvic adhesion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.591\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25(80.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30(63.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18(58.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11(61.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5(16.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1021.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6(19.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMiddle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4(8.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3(9.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSevere\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(6.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4(12.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5(27.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePresence of endometriosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.004\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMax diameter of cyst (cm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.79\u0026thinsp;\u0026plusmn;\u0026thinsp;1.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.11\u0026thinsp;\u0026plusmn;\u0026thinsp;1.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.93\u0026thinsp;\u0026plusmn;\u0026thinsp;1.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.78\u0026thinsp;\u0026plusmn;\u0026thinsp;2.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.041\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUni- or bilaterality of ovarian cysts\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.457\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUnilateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26(83.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e44(93.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e27(87.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e17(94.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBilateral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5(16.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(6.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4(12.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1(5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOperation time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68.74\u0026thinsp;\u0026plusmn;\u0026thinsp;15.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e53.66\u0026thinsp;\u0026plusmn;\u0026thinsp;16.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e75.93\u0026thinsp;\u0026plusmn;\u0026thinsp;30.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e54.39\u0026thinsp;\u0026plusmn;\u0026thinsp;23.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;0.001\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEstimated blood loss (ml)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e44.51\u0026thinsp;\u0026plusmn;\u0026thinsp;35.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e52.87\u0026thinsp;\u0026plusmn;\u0026thinsp;53.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e90.97\u0026thinsp;\u0026plusmn;\u0026thinsp;149.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e71.11\u0026thinsp;\u0026plusmn;\u0026thinsp;115.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.202\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative hospitalization\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.87\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2༎81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.00\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.11\u0026thinsp;\u0026plusmn;\u0026thinsp;1.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.629\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative pain score\u003csup\u003e*\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.90\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.89\u0026thinsp;\u0026plusmn;\u0026thinsp;0.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.83\u0026thinsp;\u0026plusmn;\u0026thinsp;0.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.624\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.778\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay 2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.805\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDay3\u003csup\u003e**\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.79\u0026thinsp;\u0026plusmn;\u0026thinsp;0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.76\u0026thinsp;\u0026plusmn;\u0026thinsp;0.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.59\u0026thinsp;\u0026plusmn;\u0026thinsp;0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.61\u0026thinsp;\u0026plusmn;\u0026thinsp;0.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.480\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHb decrease at postoperative 72 h (g/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20.71\u0026thinsp;\u0026plusmn;\u0026thinsp;8.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19.98\u0026thinsp;\u0026plusmn;\u0026thinsp;9.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.68\u0026thinsp;\u0026plusmn;\u0026thinsp;9.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21.78\u0026thinsp;\u0026plusmn;\u0026thinsp;10.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.614\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePerioperative Infection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.047\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntraoperative complications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1(3.2)\u003csup\u003e***\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2(11.1)\u003csup\u003e****\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.047\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003csup\u003ea\u003c/sup\u003eAverage and standard deviation. One-way Analysis of Variance\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003csup\u003eb\u003c/sup\u003eNumber (percentage). Chi-squared Test\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003csup\u003ec\u003c/sup\u003eNumber (percentage). Fisher Exact Test\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e\u003csup\u003ed\u003c/sup\u003eAverage and standard deviation. Kruskal-Wallis Test\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Visual Analogue Scale\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e**Only 29, 37, 29 and 18 patients in Phase I, II, III, IV were respectively included in the Day 3 VAS analysis due to the discharge of other patients.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e***1 blood transfusion\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e****1 Paralytic ileus; 1 pelvic infection\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAs shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, among all the 127 cases, there were 31 cases of vNOTES ovarian cystectomies performed in phase I, 47 cases performed in phase II, 37 cases in phase III, and 18 cases in phase IV. We further divided the cases in each phase into four subgroups including the teratoma, cystadenoma, simple cyst, and chocolate cyst according to their pathologic types. The Fisher exact test showed that there were markedly less teratoma (2 cases, 11.1%) and more cholate cysts (10 cases, 55.6%) conducted in phase IV. Conversely, there was an opposite trend in ovarian vNOTES in treating more challenging pathologic types, including chocolate cyst, the percentage of which climbed from 12.9% (4 cases) in phase I to 29.8% (14 cases) and 35.5% (11 cases) in phases II and III, respectively, to 55.6% (10 cases) in phase IV (p\u0026thinsp;=\u0026thinsp;0.039).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e \u0026emsp;Description of the pathologic type of four phases\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTeratoma(N\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCystadenoma(N\u0026thinsp;=\u0026thinsp;16)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSimple cyst(N\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eChocolate cyst(N\u0026thinsp;=\u0026thinsp;39)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase I (N\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20(64.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(9.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4(12.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4(12.9)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase II (N\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17(36.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6(12.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10(21.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e14(29.8)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase III (N\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13(41.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4(12.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3(9.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11(35.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase Ⅳ (N\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2(11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3(16.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10(55.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e0.039\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003eNumber (percentage). Fisher Exact Test\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e presents the OT of vNOTES in treating four different pathologic types of ovarian cysts in four distinct phases. The comparison in OT in treating different pathologic types within each phase did not show any statistical significance. The comparison of OT for specific pathologic types in different phases showed that there was a remarkable decrease in OT in treating teratoma and cystadenoma in the competency phase and a noticeable surge of OT in challenge phase. The mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation of vNOTES in treating teratoma dropped from 70.20\u0026thinsp;\u0026plusmn;\u0026thinsp;14.81 min in phase I to 46.06\u0026thinsp;\u0026plusmn;\u0026thinsp;11.33 min in phase II, rebounded to 74.38\u0026thinsp;\u0026plusmn;\u0026thinsp;33.75 min in phase III, and eventually decreased to 42.40\u0026thinsp;\u0026plusmn;\u0026thinsp;6.58 min in phase IV (p\u0026lt;0.001). A similar trend was also observed in vNOTES cystadenoma cystectomy, the OT of which decreased from 88.33\u0026thinsp;\u0026plusmn;\u0026thinsp;14.43 min in phase I to 50.83\u0026thinsp;\u0026plusmn;\u0026thinsp;9.37 min in phase II and surged again to 69.00\u0026thinsp;\u0026plusmn;\u0026thinsp;39.56 min in phase III and 71.67\u0026thinsp;\u0026plusmn;\u0026thinsp;20.82 min in phase IV (p\u0026thinsp;=\u0026thinsp;0 .040). vNOTES ovarian cystectomies for treating simple cysts had similar average OT in phases I (51.75\u0026thinsp;\u0026plusmn;\u0026thinsp;3.50 min) and II (55.80\u0026thinsp;\u0026plusmn;\u0026thinsp;19.46 min), but remarkably longer OT in phase III (69.33\u0026thinsp;\u0026plusmn;\u0026thinsp;12.90 min) and shorter OT in phase IV (38.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.73 min). Such comparison of vNOTES chocolate cystectomy did not reveal any statistical difference, though a longer OT in the 3rd phase (82.09\u0026thinsp;\u0026plusmn;\u0026thinsp;29.20 min) was observed (p\u0026thinsp;=\u0026thinsp;0.206).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e \u0026emsp;Operation time (in minutes) among the four phases stratified by pathologic disease\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTeratoma\u003c/p\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCystadenoma\u003c/p\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;16)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSimple cyst\u003c/p\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;20)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eChocolate cyst\u003c/p\u003e \u003cp\u003e(N\u0026thinsp;=\u0026thinsp;39)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase I (N\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e70.20\u0026thinsp;\u0026plusmn;\u0026thinsp;14.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e88.33\u0026thinsp;\u0026plusmn;\u0026thinsp;14.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e51.75\u0026thinsp;\u0026plusmn;\u0026thinsp;3.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e63.75\u0026thinsp;\u0026plusmn;\u0026thinsp;12.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.134\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase II (N\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e46.06\u0026thinsp;\u0026plusmn;\u0026thinsp;11.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50.83\u0026thinsp;\u0026plusmn;\u0026thinsp;9.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55.80\u0026thinsp;\u0026plusmn;\u0026thinsp;19.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e62.57\u0026thinsp;\u0026plusmn;\u0026thinsp;18.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.188\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase III (N\u0026thinsp;=\u0026thinsp;31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e74.38\u0026thinsp;\u0026plusmn;\u0026thinsp;33.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e69.00\u0026thinsp;\u0026plusmn;\u0026thinsp;39.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e69.33\u0026thinsp;\u0026plusmn;\u0026thinsp;12.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e82.09\u0026thinsp;\u0026plusmn;\u0026thinsp;29.20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.857\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase Ⅳ (N\u0026thinsp;=\u0026thinsp;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e42.40\u0026thinsp;\u0026plusmn;\u0026thinsp;6.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e71.67\u0026thinsp;\u0026plusmn;\u0026thinsp;20.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38.00\u0026thinsp;\u0026plusmn;\u0026thinsp;1.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e62.57\u0026thinsp;\u0026plusmn;\u0026thinsp;30.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.148\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026lt;0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.040\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.206\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003csup\u003ea\u003c/sup\u003eAverage and standard deviation. One-way Analysis of Variance\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eMultivariate regression analysis for operation time of vNOTES ovarian cystectomy\u003c/h2\u003e \u003cp\u003eTo further evaluate the potential significant association between OT and other factors, a multivariable linear regression model was established using the aforementioned methods. The results (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) revealed that there are significant associations between OT and the following variables: (1) presence of pelvic adhesion [adjusted odds ratio (OR) 7.149 (0.506, 13.792), p\u0026thinsp;=\u0026thinsp;0.035], (2) presence of bilateral cyst [adjusted OR 16.996 (2.155, 31.837), p\u0026thinsp;=\u0026thinsp;0.025], (3) max diameter of cyst[adjusted OR 2.799 (0.174, 5.425), p\u0026thinsp;=\u0026thinsp;0.037], and (4) surgeon\u0026rsquo;s experience [adjusted OR -6.118 (-11.814, -0.423), p\u0026thinsp;=\u0026thinsp;0.035].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003evNOTES is quite different from LESS and conventional laparoendoscopic surgery in multiple aspects. The establishment of a surgical path might be the most challenging one, due to the risks of injuring neighboring organs, including the rectum and urinary bladder [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. More than 1,000 cases of ovarian vNOTES were conducted in our institute between December 2018 and October 2022 which were all performed through culdotomy in the posterior vaginal fornix[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. After the initial technical exploration via approximately 30 cases of tentative vNOTES operation by two experts with more than 2 decades of experience in vaginal and laparoendoscopic surgeries, we established a standard operating procedure for conducting vNOTES and achieved better surgical outcomes and cosmetic satisfaction, faster recovery, and reduced postoperative pain compared with LESS or conventional laparoendoscopy[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In this Standard Operating Procedure (SOP), we divested the cyst in the same manner as in LESS cystectomy after establishing the surgical platform. Our clinical practice of ovarian-vNOTES also supported the viewpoint that vNOTES is easier to perform compared to LESS because of the closer proximity to the ovaries via the culdotomy entrance, less severe chopstick effects, and easier specimen removal[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] .\u003c/p\u003e \u003cp\u003eAccording to the international consensus of vNOTES experts, beginners should start from learning complete hysterectomy via vNOTES since the surgical path established therefrom would be much easier to access than the culdotomy in the posterior or anterior vaginal fornix[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Others state that vNOTES has a long learning process and may be quite challenging in inexperienced hands[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. However, in our department, we observed that ovarian cystectomy via vNOTES is much more frequently conducted even by less experienced hands due to the high incidence of ovarian and tubal diseases. Moreover, posterior vaginal fornix culdotomy is the dominantly preferred entrance for vNOTES surgery. Through a reasonably designed learning process (performing technically difficult cases in later stage or assigning them to experienced hands), our data showed that, even without experiencing vNOTES hysterectomy, surgeons with different levels of experience in performing laparoendoscopy could also master ovarian cystectomy via vNOTES in relatively less cases. The experienced surgeons only needed seven and nine cases, respectively, in the technique-acquiring phase, while the least experienced surgeons performed only 16 cases to reach competency, which supported the feasibility and promising prospect of promoting ovarian vNOTES. For young surgeons lacking experiences in conducting vaginal surgeries, they could also complete ovarian cystectomy via vNOTES after standardized training.\u003c/p\u003e \u003cp\u003eOur study assigned relatively diverse pathologic types in the surgeons\u0026rsquo; different learning phases, among which the chocolate cyst almost takes up one-third of the total cases. Some previous studies reported that endometriosis might cause adhesion in the pouch of Douglas, and that vNOTES ovarian cystectomy of chocolate cysts should be avoided.[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] Probably due to this reason, very limited cases of vNOTES endometriotic cystectomy has been reported[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Moreover, a previous study of the learning curve of adnexal vNOTES did not include chocolate cysts[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. In our study, we noticed that vNOTES may still be used to treat ovarian endometrioma with detailed preoperative examination and assessment to exclude cases with severe adhesion in the pouch of Douglas since it was not significantly related to the OT and surgical conversion did not occur; however, several cases of endometriosis and severe pelvic adhesion were included.\u003c/p\u003e \u003cp\u003eTo date, there are many studies on the learning curve of vNOTES hysterectomy, while that of vNOTES ovarian cystectomy or adnexectomy was only reported once by Huang et al [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Compared with their study, our study had a similar cohort size but included more surgeons with different levels of gynecologic endoscopy experience. Moreover, we divided the learning curves into more stages, which could be a better reference for more surgeons. We also noticed that the mass diameter in their study was not significantly associated with the OT. In our study, cyst size and bilaterality are both positively associated with the OT, which might be caused by the different pathologic types included in our study. Another mismatch between our studies was that they did not find any cut-off point for determining the volume of cases needed to achieve mastery of adnexal vNOTES. Conversely, we noticed that seven to 16 cases were enough for initial technique establishment. This might also be explained by the various pathologic and surgeon types included in our study, given that all the cases were conducted by a single high-volume surgeon in their study. Nevertheless, our results both suggested that it might be more appropriate to start learning the vNOTES technique from ovarian or adnexal vNOTES, and less cases are needed to learn the technique and achieve proficiency than the vNOTES hysterectomy.\u003c/p\u003e \u003cp\u003eThere are also several limitations in present study. Firstly, the surgeons who performed the vNOTES ovarian surgeries in our study may have performed more laparoscopic surgeries than many other less populous regions and countries, which may impair the generality of our findings. Secondly, the preoperative assessment of surgical difficulty was mainly made by subjective standards rather than standardized stratification or scoring system, which, to some extent, may hinder the assignment of surgeries to different surgeons and phases.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eOur learning curve analysis of ovarian vNOTES depicted four specific stages. vNOTES for ovarian cystectomy could be mastered after performing seven, nine, and 16 cases by surgeons with different endoscopic surgical experience. The presence of pelvic adhesion or bilateral cyst and cyst size were positively related to OT, while the surgeon\u0026rsquo;s experience was negatively correlated to OT.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003evNOTES:\u0026nbsp;transvaginal natural orifice transluminal endoscopic surgery\u003c/p\u003e\n\u003cp\u003eMIS: minimally invasive surgery\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTU-LESS: transumbilical laparoscopic single site surgery\u003c/p\u003e\n\u003cp\u003eOT: operation time\u003c/p\u003e\n\u003cp\u003eBMI: body mass index\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCUSUM: cumulative sum\u003c/p\u003e\n\u003cp\u003eHb:hemoglobin\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the ethics committee of Chengdu Women\u0026apos;s and Children\u0026apos;s Central Hospital [No.WCCH-B2021(39)]. Before the surgery, All patients were well-informed of the potential risks and advantages of vNOTES and other alternative surgical treatments, including TU-LESS or multi-port laparoscopy, and expressed their preference for vNOTES. Written informed consent was obtained from all the participants during the preoperative consultation. All identifiable private information were deleted or not transcribed while extracting the patients\u0026rsquo; pathological and clinical characteristics from the Hospital Information System to protect patients\u0026rsquo; privacy.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData supporting the conclusion are provided within the manuscript or supplementary information files. The original data are available from the corresponding authors upon reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eChengdu High-level Key Clinical Specialty Construction Project, Chengdu Municipal Health Commission Project (Grant number:2021215), Fifth Round of Chengdu Municipal Science and Technology Research Program (Grant number:2021-YF05-00627-SN), Chengdu Municipal Medical Research Project in 2023 (Grant number:2023352), and Japan China Sasakawa Medical Fellowship Program(Grant number:4408).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was designed by Dan Feng, Tianjiao Liu, and Xin Li. Dan Feng and Lu Huang completed the data collection. Tianjiao Liu, Dan Feng, and Xin Li drafted this manuscript. Tianjiao Liu and Xin Li performed the statistical analysis. Li Xiao, Li He and Yonghong Lin supervised this project and critically reviewed this manuscript. All authors participated in the revision of the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank Dr.Qiannan Hou for performing the vNOTES ovarian cystectomies. We also feel grateful for the participation of all the patients.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBorgfeldt C, Andolf E. Transvaginal sonographic ovarian findings in a random sample of women 25\u0026ndash;40 years old. Ultrasound Obstet Gynecol. 1999;13(5):345\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBottomley C, Bourne T. Diagnosis and management of ovarian cyst accidents. 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Learning Curve Analysis of Transvaginal Natural Orifice Adnexal Surgery. J Minim Invasive Gynecol. 2020;27(2):489\u0026ndash;97. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jmig.2019.04.009\u003c/span\u003e\u003cspan address=\"10.1016/j.jmig.2019.04.009\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLauterbach R, Matanes E, Amit A, et al. Transvaginal Natural Orifice Transluminal Endoscopic (vNOTES) Hysterectomy Learning Curve: Feasibility in the Hands of Skilled Gynecologists. Isr Med Assoc J. 2020;22(1):13\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-womens-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmwh","sideBox":"Learn more about [BMC Women's Health](http://bmcwomenshealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmwh/default.aspx","title":"BMC Women's Health","twitterHandle":"","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"transvaginal natural orifice transluminal endoscopic surgery, ovarian cystectomy, learning curve, cumulative sum analysis","lastPublishedDoi":"10.21203/rs.3.rs-4152484/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4152484/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground：\u003c/strong\u003eTransvaginal Natural Orifice Transluminal Endoscopy (vNOTES) is regarded as a challenging surgical technique to learn but is promising in reducing perioperative pain and significantly improves the cosmetic outcomes. Previous studies on the learning curve analysis of vNOTES mainly focuses on the hysterectomy approach, while the vNOTES ovarian cystectomy’s learning curve was merely reported thought more frequently performed than vNOTES hysterectomy. Therefore, this study seeks to analyze the learning curve of three surgeons with varying levels of experience in performing endoscopic surgery for the treatment of ovarian cysts using vNOTES.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e A total of 127 patients with ovarian cysts of a variety of pathological types were treated by\u003cstrong\u003e \u003c/strong\u003evNOTES ovarian cystectomy performed by three surgeons of different levels of endoscopic surgical experience. Each surgeon’s learning curve was plotted using the Cumulative Sum method and divided into three or four phases of technique learning at the turning point of the learning curve. The sociodemographic and clinical features of patients in each phase were then compared and factors potentially associated with operation time were also screened.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The learning curve was presented in four phases. The operation time (OT) was significantly shorter in phases II (53.66 ± 16.55 min) and IV (54.39 ± 23.45 min) as compared with phases I (68.74 ± 15.85) and III (75.93 ± 30.55) (p \u0026lt;0.001). More cases of serve pelvic adhesion and chocolate cyst were assigned in the later phases. The presence of pelvic adhesion [adjusted odds ratio (OR) 7.149 (0.506, 13.792), p = 0.035] and bilateral cyst [adjusted OR 16.996 (2.155, 31.837), p = 0.025], max diameter of cyst[adjusted OR 2.799 (0.174, 5.425), p = 0.037], and surgeon’s experience [adjusted OR -6.118 (-11.814, -0.423), p =0.035] were significantly associated with OT.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThere learning curve of ovarian vNOTES has four phases. vNOTES ovarian cystectomy could be mastered after performing seven, nine, and 16 cases by surgeons with the most, average, and least experience in gynecologic endoscopic surgeries.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration\u003c/strong\u003e: ChiCTR2200059282 (Registered on April 28th, 2022)\u003c/p\u003e","manuscriptTitle":"Learning Curve Analysis of Transvaginal Natural Orifice Transluminal Endoscopic Surgery in Treating Ovarian Cysts: A Retrospective Cohort Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-03-28 18:27:47","doi":"10.21203/rs.3.rs-4152484/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-04T03:54:24+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-05-12T09:39:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"259263142032431687312426140616479773148","date":"2024-05-02T23:07:56+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-04-24T12:30:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"ccfd8a1e-35f5-4553-bb87-4ee0cbc9a13f","date":"2024-04-10T04:31:52+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-04-10T03:37:10+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-03-27T16:13:03+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-03-25T04:19:29+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-03-25T04:19:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Women's Health","date":"2024-03-23T02:33:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-womens-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmwh","sideBox":"Learn more about [BMC Women's Health](http://bmcwomenshealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmwh/default.aspx","title":"BMC Women's Health","twitterHandle":"","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f495f602-b495-401d-880e-af16b84bcd27","owner":[],"postedDate":"March 28th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-08-01T17:10:09+00:00","versionOfRecord":{"articleIdentity":"rs-4152484","link":"https://doi.org/10.1186/s12905-024-03261-2","journal":{"identity":"bmc-womens-health","isVorOnly":false,"title":"BMC Women's Health"},"publishedOn":"2024-07-25 16:16:07","publishedOnDateReadable":"July 25th, 2024"},"versionCreatedAt":"2024-03-28 18:27:47","video":"","vorDoi":"10.1186/s12905-024-03261-2","vorDoiUrl":"https://doi.org/10.1186/s12905-024-03261-2","workflowStages":[]},"version":"v1","identity":"rs-4152484","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4152484","identity":"rs-4152484","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}