Evaluation of the Treatment of High Intensity Focused Ultrasound Combined With Suction Curettage for Exogenous Cesarean Scar Pregnancy

Evaluation of the Treatment of High Intensity Focused Ultrasound Combined With Suction Curettage for Exogenous Cesarean Scar Pregnancy | 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 Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Evaluation of the Treatment of High Intensity Focused Ultrasound Combined With Suction Curettage for Exogenous Cesarean Scar Pregnancy Lin Mu, Huifang Weng, Xiaoyun Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-740249/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 18 Mar, 2022 Read the published version in Archives of Gynecology and Obstetrics → Version 1 posted 5 You are reading this latest preprint version Abstract Purpose: To evaluate the effectiveness of high intensity focused ultrasound (HIFU) combined with suction curettage in the treatment of exogenous cesarean scar pregnancy (CSP). Methods: A total of 41 patients diagnosed with exogenous CSP were enrolled in this study. All patients received HIFU treatment combined with suction curettage. Results: Twenty-nine patients were administered one session of HIFU ablation. In addition, the other 12 patients received 2 HIFU sessions. Suction curettage was performed in all patients after HIFU, and no patient was converted to laparoscopy or hysterectomy. The mean blood loss during suction curettage was 99 ml. Three patients received two sessions of suction curettage. The success rate of our study was 92.68%. The mean time for serum β-HCG normalization was 23.18±3.13 days. The average menstruation recovery time was 29.38±3.34 days. Based on the blood loss during suction curettage, 41 patients were divided into a bleeding group and a control group. The size of the gestational sac in the bleeding group (3.80±0.87 cm) was larger than that in the control group (3.39±0.77 cm) ( P <0.05). The thickness of the myometrium between the bladder and gestational sac in the bleeding group (2.37±0.89 mm) was less than that in the control group (2.75±0.75 mm) ( P <0.05). Conclusion: The results suggested that HIFU combined with suction curettage could be considered an effective treatment for exogenous CSP of < 9 weeks. The size of the gestational sac and the thickness of the myometrium between the bladder and gestational sac might be high-risk factors for blood loss during this treatment. Obstetrics & Gynecology Exogenous cesarean scar pregnancy High intensity focused ultrasound Suction curettage High-risk factors Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Cesarean scar pregnancy (CSP) is a rare variant of ectopic pregnancy in which the gestational sac implants into the site of a previous cesarean scar [ 1 ]. With the increase in the cesarean section rate and the improvement of diagnostic technology [ 2 ], the incidence of CSP is expected to increase further. The overall principle of CSP treatment is to remove gestational tissue, reduce blood loss and ensure the safety of patients. Various treatments for CSP have been studied before, including methotrexate (MTX), uterine artery embolization (UAE), high intensity focused ultrasound (HIFU) and surgery [ 3 – 5 ]. Although an increasing number of CSP cases have been reported, there is still no consensus on its treatment until now [ 6 ]. According to the growth direction and location of gestational sac in uterine scars, CSP is divided into two types: endogenous CSP refers to growth of the gestational sac toward the isthmus and uterine cavity, while the gestational sac of exogenous CSP implants into the deep muscle layer of the cesarean scar and grows toward the bladder and abdominal cavity [ 7 , 8 ]. Some reports have concluded that there is a higher risk of massive hemorrhage and even death in exogenous CSP because the muscle fibers in previous cesarean scars are relatively insufficient for elastic contractility [ 9 , 10 ]. Therefore, effective and safe treatment is particularly important for this kind of patient. As reported before, laparoscopy administered for exogenous CSP has achieved good results [ 11 , 12 ]. While eliminating pregnancy tissue, laparoscopy could provide an opportunity to repair uterine scar defects, which would be helpful to avoid the recurrence of CSP [ 13 ]. However, the exact pathogenetic mechanism of CSP remains unclear. It has been reported that 6%-10% of women after cesarean section have different degrees of scar diverticulum [ 14 ], which is significantly higher than the incidence of CSP [ 15 ]. CSP patients can have a normal pregnancy again after conservative treatment [ 16 ]. These studies suggest that scar diverticulum may not be the only cause of CSP. Although surgery has the advantage of repairing scars at the same time, it might also be complicated by anesthetic complications, postoperative adhesion, and poor healing of local scars [ 17 ]. A previous study also concluded that no sufficient evidence was found to elucidate whether reproductive outcomes after CSP are impacted by the management types adopted [ 18 ]. In view of the present situation, it seems that effective and less traumatic approaches should be taken. UAE combined with MTX has been reported as an effective treatment for exogenous CSP [ 19 ]. However, complications from UAE, such as long-term premature ovarian failure, post thrombotic syndrome, pulmonary embolism, and septic rectal perforation, occur [ 20 – 23 ]. Recently, HIFU has been reported to achieve satisfactory results in the treatment of fibroids and adenomyosis [ 24 , 25 ]. Several studies have shown that HIFU followed by suction curettage is safe and effective in the treatment of CSP [ 16 , 26 ]. However, the therapeutic effect of HIFU on different types of CSP has not been reported. In this study, we retrospectively evaluated the treatment of HIFU combined with suction curettage to explore whether it is effective and safe for exogenous CSP patients. Materials And Methods Patient collection In this retrospective study we enrolled 41 patients diagnosed with exogenous CSP from September 2016 to September 2020 at the Second Affiliated Hospital, School of Medicine, Zhejiang University. The research protocol was approved by the ethics committee and institutional review board of our institution. The inclusion criteria were as follows: 1) previous history of a prior cesarean scar, 2) history of amenorrhea < 9 weeks and an increased level of β-human chorionic gonadotropin (β-HCG) (more than 5 mIU/mL), 3) ultrasound (Fig. 1 ) and magnetic resonance imaging (Fig. 2 ) meeting the criteria of exogenous CSP recommended by Godin et al [ 27 ] and Vial et al [ 7 ], with gestational sac implantation into the myometrium of a scar diverticulum and growth toward the bladder and abdominal cavity. Two experienced gynecological radiologists confirmed the sonographic and MRI results of all patients. Patients with heavy bleeding or unstable vital signs were excluded. The clinical characteristics, parameters during treatment, adverse events, and follow-up results were collected. HIFU ablation HIFU was performed by using a PRO200 focused ultrasound therapeutic system (Shenzhen PRO Medical Technology Co. Ltd, Shenzhen, China). The B-mode ultrasound used for monitoring was Mylab70 (Esaote, Genoa, Italy). HIFU ablation was performed on every patient without conscious sedation. The patient was placed in the prone position on the HIFU system. The degassed water bag was positioned on the abdominal wall. During the operation, we used ultrasound to choose the location of the target area in real time, and the sagittal plane of ultrasound scanning was selected (Fig. 3 ). The pregnant tissue was divided into different treatment levels (the spacing was 3 mm), and the treatment plan was formulated. HIFU ablation was performed from the innermost part and extended to the outside by section. The sound output power was 250–300 W. HIFU ablation was stopped when color Doppler ultrasound revealed that the blood flow signal of the pregnancy tissue disappeared or the gray level of the target tissue changed. Contrast-enhanced ultrasound was performed to examine the blood perfusion of the pregnancy tissue. If a blood supply was found, another session of HIFU ablation was performed the next day. Suction curettage Suction curettage guided by ultrasound was performed under general anesthesia one to three days after HIFU ablation. The lithotomy position was employed for all patients. We measured the depth of the uterus and then dilated the cervix gradually with the uterine dilators. A 7 mm suction cannula was inserted into the uterine cavity with a vacuum pressure of 40 Pa. The cannula was moved forth and back and rolled gently to remove the pregnancy tissues. If an ultrasound check showed residual tissue, curettage was performed very gently. If active uterine bleeding > 200 ml occurred during or after suction curettage, we inserted a No. 14 Foley catheter balloon into the intrauterine cavity for compression hemostasis and removed it after 24 hours. The weight of medical gauze was used to measure the blood loss during or after suction curettage. Follow up After suction curettage, vital signs and vaginal bleeding of all patients were closely observed for 48 hours, and then they were discharged. A transvaginal ultrasonography examination was performed one week after suction curettage. If remnant tissue was found, the second session of suction curettage was performed immediately. At the same time, the patients underwent serum β-HCG testing every week until exhibiting normal levels. Serum β-HCG levels, the duration of vaginal bleeding, ultrasound assessments, menstruation recovery and adverse effects were followed up. Successful cases were defined as: (1) no additional methotrexate or surgical intervention; and (2) normalization of serum β-HCG levels and recovery of menstruation. Statistical analysis Statistical analysis was performed by SPSS software (SPSS 22.0, IBM Company, Chicago, IL). Patient characteristics are described as proportions for categorical variables and were analyzed by the chi square test. Continuous variables with a normal distribution are reported as the mean ± SD and were analyzed by Student’s t test. Continuous variables without a normal distribution are reported as medians and interquartile ranges and were analyzed by the Mann-Whitney U test. Correlation analysis between variables was performed by Spearman rank analysis. A P value < 0.05 was defined as a significant difference. Results Characteristics of exogenous CSP patients Patient characteristics are summarized in Table 1 . The median age of the patients was 29 years. The mean BMI was 22.62 ± 5.27 kg/m 2 . The average gestational age was 50.31 ± 8.27days. The median interval from the last cesarean section to CSP was 38 months. Among all patients, 20 patients (48.78%) had one previous cesarean delivery, 18 patients (43.90%) had two such deliveries, and 3 patients (7.32%) had three such deliveries. Thirteen patients (31.71%) had both light painless vaginal bleeding and lower abdominal pain. Twelve patients (29.27%) suffered from abdominal pain without vaginal bleeding. Sixteen patients (39.02%) complained of only light painless vaginal bleeding. Fetal cardiac activity was found in 6 patients (14.63%). Before the treatment the median serum β-HCG level was 26,207 ± 8492 mIU/ml. The average gestation sac size was 3.49 ± 0.94 cm. The median thickness of myometrium between the bladder and the gestational sac was 2.65 ± 1.10 mm. Table 1 Demographic characteristics of exogenous CSP patients (n = 41) Variables value Maternal age (years) BMI (kg/m 2 ) Gestational age (days) Time interval since last CS (months) Number of previous CS (n) 1 2 3 29(25, 39) 22.62 ± 5.27 50.31 ± 8.27 38(21, 84) 20(48.78%) 18(43.90%) 3(7.32%) Abnormal pain only (n) 12(29.27%) Light painless vaginal bleeding only (n) 16(39.02%) Light painless vaginal bleeding and abdominal pain (n) Fetal cardiatic activity Pre-treatment serum β-HCG (mIU/mL) Gestation sac size (cm) Thickness of myometrium between gestation sac and the bladder (mm) 13(31.71%) 6(14.63%) 26207 ± 8492 3.49 ± 0.94 2.65 ± 1.10 β-HCG = β-human chorionic gonadotropin; CS = cesarean section HIFU ablation evaluation HIFU treatment was successfully carried out for all patients (Table 2 ). One session of HIFU ablation therapy was performed for 29 patients (70.73%). The other 12 patients (29.27%) received 2 HIFU sessions. The average HIFU treatment time was 83 minutes. The median HIFU sonication time was 705 s. After HIFU ablation, no blood perfusion was found in the pregnancy tissue by contrast-enhanced ultrasound (Fig. 4 , 5 ). Simultaneously, we could not detect fetal cardiac activity. During HIFU ablation, all patients complained of pain in the sacra or lower abdomen. A 10-point scale was used, and the pain score ranged from 1 to 3 points. The pain was relieved within 1 week without any special medical treatment. A hot skin sensation was complained of by fourteen patients. However, we found no skin burns in those patients. Table 2 The treatment results Variables value HIFU Median treatment time(min) Median sonication time(s) Session of HIFU ablation 1 2 Suction curettage The uterus cavity depth(cm) Surgical time(min) Blood loss during curettage (ml) Treatments for bleeding during suction curettage No hemostasis (n) Foley catheter balloon used (n) Session of suction curettage 1 2 Follow up 83(60, 132) 705 (614,1142) 29(70.73%) 12(29.27%) 9.64±1.43 35.45±10.23 99 (30, 240) 29(70.73%) 12(29.27%) 38(92.68%) 3 (7.32%) Duration of vaginal bleeding post-curettage (days) 9.72±3.92 Time of menstruation recovery(days) 29.38±3.34 Time for serum β-HCG normalization(days) 23.18±3.13 β-HCG=β-human chorionic gonadotropin Table 3 Comparison of characteristics of exogenous CSP patients in two groups Variables The bleeding group(n = 12) The control group (n = 29) P Maternal age(years) BMI Gestational age Number of previous CS (n) Time Interval since last CS(m) Pre-treatment serum β-HCG (mIU/mL) Gestational sac diameter (mm) Thickness of myometrium (mm) 30(24, 41) 23.45 ± 3.45 51.23 ± 4.25 2(1–3) 42(25, 89) 27148 ± 6746 3.80 ± 0.87 2.37 ± 0.89 29(25, 38) 22.87 ± 2.13 49.83 ± 5.15 2(1–3) 37(19, 82 ) 25864 ± 8769 3.39 ± 0.77 2.75 ± 0.75 0.453 0.367 0.312 0.419 0.187 0.328 0.019 0.014 β-HCG = β-human chorionic gonadotropin; CS = cesarean section Suction curettage assessment and follow-up Suction curettage was performed on all patients after HIFU treatment (Table 2 ). No patient was converted to laparoscopy or hysterectomy. The median blood loss during suction curettage was 99 ml. We inserted the No. 14 Foley catheter balloon into the intrauterine cavity to manage massive vaginal bleeding (> 200 ml) in 12 patients. The catheter balloon was removed 24 hours later. Ultrasound checks were performed by an ultrasound specialist for every patient one week after suction curettage. The pregnancy tissues were successfully removed in 38 patients (92.68%). Three patients (7.32%) received a second session of suction curettage with blood loss of 20 ml for remnant pregnancy tissues. All patients received follow-up through clinical visits. The median period of vaginal bleeding was 9.72 ± 3.92 days. The mean time for β-HCG normalization was 23.18 ± 3.13 days. The average time of menstruation recovery was 29.38 ± 3.34 days (Table 2 ). No complications occurred during the follow-up period. Analysis of risk factors for blood loss during suction curettage Based on the use of catheter balloons during suction curettage, 41 patients were divided into two groups. The patients who used catheter balloons were considered the bleeding group (blood loss > 200 ml). The other patients were grouped into the control group. Between the two groups, we found no significant difference in terms of age, BMI, gestational age, number of previous cesarean sections, time interval from the last cesarean section, or β-HCG level before treatment ( P > 0.05). However, the size of gestational sac in the bleeding group (3.80 ± 0.87 cm) was larger than that in the control group (3.39 ± 0.77 cm) ( P < 0.05). The thickness of the interval myometrium between the bladder and gestational sac in the bleeding group (2.37 ± 0.89 mm) was less than that in the control group (2.75 ± 0.75 mm) ( P < 0.01). In all exogenous CSP patients, there was a positive correlation between the size of the gestational sac and blood loss during suction curettage ( r = 0.401, P < 0.01). Meanwhile, the thickness of the interval myometrium between the bladder and gestational sac had a negative correlation with blood loss during suction curettage ( r = -0.423, P < 0.01). Discussion To our knowledge, this is the first report on the use of HIFU combined with suction curettage for treating exogenous CSP. The success rate in this study was 92.68% and no patient was converted to laparoscopy or hysterectomy. The median intraoperative blood loss during suction curettage was 99 ml. The average time for serum β-HCG level normalization was 23.18 ± 3.13 days, and the median time for menstruation recovery was 29.38 ± 3.34 days. Although there are some deficiencies in HCG levels and menstrual recovery compared with those after laparoscopy [ 11 , 12 ], our protocol provides the possibility of one conservative treatment for exogenous CSP patients. We also reviewed the literature about the treatment of UAE combined with suction curettage for CSP. Introspective blood loss ranged from 14 ml to 114 ml, and serum β-HCG returned to normal levels within 15 to 29 days [ 26 , 28 , 29 ]. Our study obtained the similar results as those from the treatment of UAE combined with suction curettage and avoided the complications of UAE. Theoretically, HIFU mainly uses high intensity ultrasound to focus on the internal target of the body in vitro. We speculate that HIFU contributes to the treatment of exogenous CSP in three ways. First, HIFU ablation can cause necrosis of the corresponding lesion cells. Through the mechanical effect of high intensity ultrasound, the high-temperature thermal effect formed an instantaneous high temperature > 60℃, which led to necrosis in the pregnancy tissue. Second, the cavitation effect of HIFU could loosen the adhesion between the myometrium at the uterine scar and the gestational sac, which would be helpful for removing the pregnancy tissue [ 30 ]. Finally, HIFU has been reported to be used for the ablation of small vessels with a diameter < 2 mm [ 31 ]. The thermal energy deposited in the pregnancy tissue can destroy small blood vessels. As seen on color Doppler assessment, the blood perfusion in the pregnancy tissue disappeared. For the reasons mentioned above, HIFU could make suction curettage a smoother process for removing the pregnancy tissue and reduce the risk of heavy hemorrhage. As reported before, adverse effects, such as sciatic and lower abdominal pain, injury to the bowel and bladder, fever, and skin burns, occur during HIFU ablation [ 32 – 34 ]. In the ablation for exogenous CSP, the target site was located at the anterior wall of the cervix, which was located away from the bowl in the pelvic cavity. Ablation began from the innermost part, which was not near the bladder. With simultaneous ultrasound monitoring, HIFU ablation in our study caused no damage to surrounding organs. Although all patients complained of abdominal or sacral pain during the HIFU ablation, no patients needed further treatment. Due to the characteristics of exogenous CSP, there is a risk of uterine perforation and substantial hemorrhage during suction curettage. To avoid uterine perforation during suction curettage, we first carried out vacuum suction. If an ultrasound check showed residual tissue, curettage was performed very gently. In our study, no uterine perforations occurred. A previous study reported that perforation of the uterus occurred in a CSP patient during suction curettage after HIFU ablation [ 35 ]. The author attributed this event to the 2 mm thickness of the interval myometrium between the bladder and gestation sac. In our study, the thickness of the thinnest interval myometrium was 1.5 mm, but no uterine perforation occurred. Therefore, we deduce that uterine perforation is a result of comprehensive factors. For patients with bleeding greater than 200 ml, we used a Foley balloon catheter to compress the hemorrhage, which avoided the possibility of conversion to laparotomy. However, there were still 3 patients who had to undergo a second suction curettage. We found that all three of these patients were administered Foley balloon catheters during the suction curettage. Thus, the suction curettage was interrupted, which resulted in residual pregnancy tissue. We also found that the size of the gestational sac and the thickness of the interval myometrium between the bladder and gestational sac were correlated with blood loss during suction curettage. Our results were consistent with those of previous studies [ 36 , 37 ]. Adhesion between the myometrium at the uterine scar and the gestational sac will form bleeding wounds as the pregnancy tissue is removed [ 38 ]. The wound will expand with the increase in the gestational sac, which also elevates the risk of hemorrhage. The weakness of the myometrium is accompanied by poor contractility, which makes it difficult to close the bleeding vessels [ 39 , 40 ]. We also found no significant difference in terms of age, BMI, gestational age, interval time from last CS, or β-HCG level before treatment between the two groups. We noticed that a previous study considered the β-HCG level to be a risk factor for massive hemorrhage [ 41 ]. As a biochemical index representing trophoblastic cell activity, the β-HCG level of exogenous CSP may not be high due to the muscular layer defects and insufficiency of the blood supply. The inconsistency might result from the different grouping standards adopted in different studies. In conclusion, our results indicate that HIFU combined with suction curettage is effective and safe in the treatment of exogenous CSP of < 9 weeks. We also found that the size of the gestational sac and the thickness of the interval myometrium between the bladder and gestational sac might be high-risk factors for blood loss during this treatment. Limited by the retrospective analysis and the sample number, we should validate our findings by carrying out prospective and large-scale multicenter studies in the future. Declarations Competing interests: The authors declare that they have no conflicts of interest and nothing to disclose. 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(2015) High-intensity focused ultrasound combined with suction curettage for the treatment of cesarean scar pregnancy Medicine94(18):e854. https://doi.org/10.1097/MD.0000000000000854. Zhang Y, Zhang Z, Liu X, Zhang L, Hong F, Lu M.Zhang Y, et al. (2021) Risk factors for massive hemorrhage during the treatment of cesarean scar pregnancy: a systematic review and meta-analysis Arch Gynecol Obstet. 303(2):321-328. https://doi.org/10.1007/s00404-020-05877-9. Zhang Y, Zhang C, He J, Bai J, Zhang L.Zhang Y, et al. (2018) The impact of gestational sac size on the effectiveness and safety of high intensity focused ultrasound combined with ultrasound-guided suction curettage treatment for caesarean scar pregnancy Int J Hyperthermia. 35(1):291-297. https://doi.org/10.1080/02656736.2018.1496485. Le A, Li M, Xu YH et al. (2019) Different surgical approaches to 313 cesarean scar pregnancies. J Minim Invasive Gynecol 26: 148-152. https://doi.org/10.1016/j.jmig.2018.03.035. Shao MJ, Hu MX, Xu XJ et al (2013) Management of caesarean scar pregnancies using an intrauterine or abdominal approach based on the myometrial thickness between the gestational mass and the bladder wall. Gynecol Obs Invest 76:151–157. https://doi.org/10.1016/j.ejogrb.2019.04.008. Ma Y, Shao M, Shao X, et al, (2017) Analysis of risk factors for ntraoperative hemorrhage of cesarean scar pregnancy. Medicine 96(25):e7327．https://doi.org/10.1097/MD.0000000000007327. Fang Q, Sun L, Tang Y et al (2017) Quantitative risk assessment to guide the treatment of cesarean scar pregnancy. Int J Gynaecol Obs 139:78–83. https://doi.org/10.1002/ijgo.12240. Cite Share Download PDF Status: Published Journal Publication published 18 Mar, 2022 Read the published version in Archives of Gynecology and Obstetrics → Version 1 posted Reviews received at journal 07 Dec, 2021 Reviewers invited by journal 07 Dec, 2021 Editor invited by journal 05 Aug, 2021 Editor assigned by journal 22 Jul, 2021 First submitted to journal 21 Jul, 2021 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies 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-740249","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":68467499,"identity":"c4d68aee-c359-4e7d-8cdb-2bfe09f5649c","order_by":0,"name":"Lin Mu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIie3RMQrCMBSA4VcKnSJZI4Je4UnBpYKDF6lLu1hwck4QnHqAgINn8AaRgFOpq4NDwQt0dFCw6eRU4yaYf3vwPkISAJfrB6NUiCrG6RBANWNgQfpSa6xXSWhPUCVJX9Z6wdvRhoAqwpCgTveiQKjXGuiOdwtvk49vBNNM8AI9WWpgV9VNfGhPibINFOj3thqQxd0kgOVkQNBPA0OeNoSAuT7OY2KIZ0MYM4+MyVjCaXXMy5SwywcyO5uvfExHI6kP1X0dDan8QN7OU+1nEtv9Jsq/WHa5XK6/6gXcEUX+fuR5bQAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0002-1449-2646","institution":"Zhejiang University, school of medicine, second affiliated hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Lin","middleName":"","lastName":"Mu","suffix":""},{"id":68467500,"identity":"54c10750-7882-4d16-8466-31a639b6c749","order_by":1,"name":"Huifang Weng","email":"","orcid":"","institution":"The Second Affiliated Hospital, School of Medicine, Zhejiang University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Huifang","middleName":"","lastName":"Weng","suffix":""},{"id":68467501,"identity":"e4167350-d086-403c-8ad1-9854696c6b8b","order_by":2,"name":"Xiaoyun Wang","email":"","orcid":"","institution":"Zhejiang University, school of medicine, second affiliated hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Xiaoyun","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2021-07-22 04:37:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-740249/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-740249/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00404-022-06487-3","type":"published","date":"2022-03-18T20:02:35+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":16284875,"identity":"8c42bc3f-21b3-4bb2-939a-aa74790287f9","added_by":"auto","created_at":"2021-12-08 15:53:52","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":618106,"visible":true,"origin":"","legend":"Exogenous cesarean scar pregnancy located in the previous cesarean scar.","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-740249/v1/bb36b1eb9ac1082fcfeca52c.png"},{"id":16284400,"identity":"8bf4659a-cdb7-4a43-a1e0-9a248e63972b","added_by":"auto","created_at":"2021-12-08 15:50:52","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":409070,"visible":true,"origin":"","legend":"Sagittal view of the magnetic resonance imaging showed a gestational sac located in the previous cesarean scar.","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-740249/v1/0232faa8a6cf41b034d1b21b.png"},{"id":16284401,"identity":"87cef6e2-3fbb-4a87-9348-30fbeced4e57","added_by":"auto","created_at":"2021-12-08 15:50:52","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":305772,"visible":true,"origin":"","legend":"Treatment mode of high intensity focused ultrasound ablation.","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-740249/v1/0f31c0f82739bdaf929d0a8c.png"},{"id":16284403,"identity":"60ffe0cb-0392-43b2-90d5-f5ea6c7d868a","added_by":"auto","created_at":"2021-12-08 15:50:52","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":253120,"visible":true,"origin":"","legend":"Abundant perfusion in the myometrium of the surrounding CSP scar was found by contrast enhanced ultrasound before HIFU.","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-740249/v1/5dc25c8442fc259407c524cc.png"},{"id":16284404,"identity":"d2c7bb6c-1a68-401e-b528-117030f0c9f9","added_by":"auto","created_at":"2021-12-08 15:50:52","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":244752,"visible":true,"origin":"","legend":"Contrast enhanced ultrasound revealed no enhancement in the myometrium of the CSP scar after HIFU.","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-740249/v1/347a83fd6f92d0a11132f92c.png"},{"id":19702508,"identity":"2b736090-840b-4b9b-9dae-8788e4d63e1d","added_by":"auto","created_at":"2022-03-28 20:04:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1938654,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-740249/v1/bf0db291-533a-4553-a5c0-9a16a23f53ed.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eEvaluation of the Treatment of High Intensity Focused Ultrasound Combined With Suction Curettage for Exogenous Cesarean Scar Pregnancy\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCesarean scar pregnancy (CSP) is a rare variant of ectopic pregnancy in which the gestational sac implants into the site of a previous cesarean scar [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. With the increase in the cesarean section rate and the improvement of diagnostic technology [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], the incidence of CSP is expected to increase further. The overall principle of CSP treatment is to remove gestational tissue, reduce blood loss and ensure the safety of patients. Various treatments for CSP have been studied before, including methotrexate (MTX), uterine artery embolization (UAE), high intensity focused ultrasound (HIFU) and surgery [\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Although an increasing number of CSP cases have been reported, there is still no consensus on its treatment until now [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAccording to the growth direction and location of gestational sac in uterine scars, CSP is divided into two types: endogenous CSP refers to growth of the gestational sac toward the isthmus and uterine cavity, while the gestational sac of exogenous CSP implants into the deep muscle layer of the cesarean scar and grows toward the bladder and abdominal cavity [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Some reports have concluded that there is a higher risk of massive hemorrhage and even death in exogenous CSP because the muscle fibers in previous cesarean scars are relatively insufficient for elastic contractility [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Therefore, effective and safe treatment is particularly important for this kind of patient. As reported before, laparoscopy administered for exogenous CSP has achieved good results [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. While eliminating pregnancy tissue, laparoscopy could provide an opportunity to repair uterine scar defects, which would be helpful to avoid the recurrence of CSP [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. However, the exact pathogenetic mechanism of CSP remains unclear. It has been reported that 6%-10% of women after cesarean section have different degrees of scar diverticulum [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], which is significantly higher than the incidence of CSP [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. CSP patients can have a normal pregnancy again after conservative treatment [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. These studies suggest that scar diverticulum may not be the only cause of CSP. Although surgery has the advantage of repairing scars at the same time, it might also be complicated by anesthetic complications, postoperative adhesion, and poor healing of local scars [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. A previous study also concluded that no sufficient evidence was found to elucidate whether reproductive outcomes after CSP are impacted by the management types adopted [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In view of the present situation, it seems that effective and less traumatic approaches should be taken. UAE combined with MTX has been reported as an effective treatment for exogenous CSP [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. However, complications from UAE, such as long-term premature ovarian failure, post thrombotic syndrome, pulmonary embolism, and septic rectal perforation, occur [\u003cspan additionalcitationids=\"CR21 CR22\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Recently, HIFU has been reported to achieve satisfactory results in the treatment of fibroids and adenomyosis [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Several studies have shown that HIFU followed by suction curettage is safe and effective in the treatment of CSP [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. However, the therapeutic effect of HIFU on different types of CSP has not been reported. In this study, we retrospectively evaluated the treatment of HIFU combined with suction curettage to explore whether it is effective and safe for exogenous CSP patients.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003ePatient collection\u003c/h2\u003e\n \u003cp\u003eIn this retrospective study we enrolled 41 patients diagnosed with exogenous CSP from September 2016 to September 2020 at the Second Affiliated Hospital, School of Medicine, Zhejiang University. The research protocol was approved by the ethics committee and institutional review board of our institution. The inclusion criteria were as follows: 1) previous history of a prior cesarean scar, 2) history of amenorrhea\u0026thinsp;\u0026lt;\u0026thinsp;9 weeks and an increased level of \u0026beta;-human chorionic gonadotropin (\u0026beta;-HCG) (more than 5 mIU/mL), 3) ultrasound (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e) and magnetic resonance imaging (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e) meeting the criteria of exogenous CSP recommended by Godin et al [\u003cspan class=\"CitationRef\"\u003e27\u003c/span\u003e] and Vial et al [\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e], with gestational sac implantation into the myometrium of a scar diverticulum and growth toward the bladder and abdominal cavity. Two experienced gynecological radiologists confirmed the sonographic and MRI results of all patients. Patients with heavy bleeding or unstable vital signs were excluded. The clinical characteristics, parameters during treatment, adverse events, and follow-up results were collected.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec4\"\u003e\n \u003ch2\u003eHIFU ablation\u003c/h2\u003e\n \u003cp\u003eHIFU was performed by using a PRO200 focused ultrasound therapeutic system (Shenzhen PRO Medical Technology Co. Ltd, Shenzhen, China). The B-mode ultrasound used for monitoring was Mylab70 (Esaote, Genoa, Italy). HIFU ablation was performed on every patient without conscious sedation. The patient was placed in the prone position on the HIFU system. The degassed water bag was positioned on the abdominal wall. During the operation, we used ultrasound to choose the location of the target area in real time, and the sagittal plane of ultrasound scanning was selected (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). The pregnant tissue was divided into different treatment levels (the spacing was 3 mm), and the treatment plan was formulated. HIFU ablation was performed from the innermost part and extended to the outside by section. The sound output power was 250\u0026ndash;300 W. HIFU ablation was stopped when color Doppler ultrasound revealed that the blood flow signal of the pregnancy tissue disappeared or the gray level of the target tissue changed. Contrast-enhanced ultrasound was performed to examine the blood perfusion of the pregnancy tissue. If a blood supply was found, another session of HIFU ablation was performed the next day.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec5\"\u003e\n \u003ch2\u003eSuction curettage\u003c/h2\u003e\n \u003cp\u003eSuction curettage guided by ultrasound was performed under general anesthesia one to three days after HIFU ablation. The lithotomy position was employed for all patients. We measured the depth of the uterus and then dilated the cervix gradually with the uterine dilators. A 7 mm suction cannula was inserted into the uterine cavity with a vacuum pressure of 40 Pa. The cannula was moved forth and back and rolled gently to remove the pregnancy tissues. If an ultrasound check showed residual tissue, curettage was performed very gently. If active uterine bleeding\u0026thinsp;\u0026gt;\u0026thinsp;200 ml occurred during or after suction curettage, we inserted a No. 14 Foley catheter balloon into the intrauterine cavity for compression hemostasis and removed it after 24 hours. The weight of medical gauze was used to measure the blood loss during or after suction curettage.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec6\"\u003e\n \u003ch2\u003eFollow up\u003c/h2\u003e\n \u003cp\u003eAfter suction curettage, vital signs and vaginal bleeding of all patients were closely observed for 48 hours, and then they were discharged. A transvaginal ultrasonography examination was performed one week after suction curettage. If remnant tissue was found, the second session of suction curettage was performed immediately. At the same time, the patients underwent serum \u0026beta;-HCG testing every week until exhibiting normal levels. Serum \u0026beta;-HCG levels, the duration of vaginal bleeding, ultrasound assessments, menstruation recovery and adverse effects were followed up.\u003c/p\u003e\n \u003cp\u003eSuccessful cases were defined as: (1) no additional methotrexate or surgical intervention; and (2) normalization of serum \u0026beta;-HCG levels and recovery of menstruation.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec7\"\u003e\n \u003ch2\u003eStatistical analysis\u003c/h2\u003e\n \u003cp\u003eStatistical analysis was performed by SPSS software (SPSS 22.0, IBM Company, Chicago, IL). Patient characteristics are described as proportions for categorical variables and were analyzed by the chi square test. Continuous variables with a normal distribution are reported as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD and were analyzed by Student\u0026rsquo;s \u003cem\u003et\u003c/em\u003e test. Continuous variables without a normal distribution are reported as medians and interquartile ranges and were analyzed by the Mann-Whitney U test. Correlation analysis between variables was performed by Spearman rank analysis. A \u003cem\u003eP\u003c/em\u003e value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was defined as a significant difference.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n\u003ch2\u003eCharacteristics of exogenous CSP patients\u003c/h2\u003e\n\u003cp\u003ePatient characteristics are summarized in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The median age of the patients was 29 years. The mean BMI was 22.62\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;5.27 kg/m\u003csup\u003e2\u003c/sup\u003e. The average gestational age was 50.31\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;8.27days. The median interval from the last cesarean section to CSP was 38 months. Among all patients, 20 patients (48.78%) had one previous cesarean delivery, 18 patients (43.90%) had two such deliveries, and 3 patients (7.32%) had three such deliveries. Thirteen patients (31.71%) had both light painless vaginal bleeding and lower abdominal pain. Twelve patients (29.27%) suffered from abdominal pain without vaginal bleeding. Sixteen patients (39.02%) complained of only light painless vaginal bleeding. Fetal cardiac activity was found in 6 patients (14.63%). Before the treatment the median serum \u0026beta;-HCG level was 26,207\u0026thinsp;\u0026plusmn;\u0026thinsp;8492 mIU/ml. The average gestation sac size was 3.49\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94 cm. The median thickness of myometrium between the bladder and the gestational sac was 2.65\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10 mm.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eDemographic characteristics of exogenous CSP patients (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth style=\"width: 509px;\" align=\"left\"\u003e\n\u003cp\u003eVariables\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 155px;\" align=\"left\"\u003e\n\u003cp\u003evalue\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 509px;\" align=\"left\"\u003e\n\u003cp\u003eMaternal age (years)\u003c/p\u003e\n\u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n\u003cp\u003eGestational age (days)\u003c/p\u003e\n\u003cp\u003eTime interval since last CS (months)\u003c/p\u003e\n\u003cp\u003eNumber of previous CS (n)\u003c/p\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003cp\u003e3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 155px;\" align=\"left\"\u003e\n\u003cp\u003e29(25, 39)\u003c/p\u003e\n\u003cp\u003e22.62\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;5.27\u003c/p\u003e\n\u003cp\u003e50.31\u0026thinsp;\u0026plusmn;\u0026thinsp;8.27\u003c/p\u003e\n\u003cp\u003e38(21, 84)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e20(48.78%)\u003c/p\u003e\n\u003cp\u003e18(43.90%)\u003c/p\u003e\n\u003cp\u003e3(7.32%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 509px;\" align=\"left\"\u003e\n\u003cp\u003eAbnormal pain only (n)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 155px;\" align=\"left\"\u003e\n\u003cp\u003e12(29.27%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 509px;\" align=\"left\"\u003e\n\u003cp\u003eLight painless vaginal bleeding only (n)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 155px;\" align=\"left\"\u003e\n\u003cp\u003e16(39.02%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 509px;\" align=\"left\"\u003e\n\u003cp\u003eLight painless vaginal bleeding and abdominal pain (n)\u003c/p\u003e\n\u003cp\u003eFetal cardiatic activity\u003c/p\u003e\n\u003cp\u003ePre-treatment serum \u0026beta;-HCG (mIU/mL)\u003c/p\u003e\n\u003cp\u003eGestation sac size (cm)\u003c/p\u003e\n\u003cp\u003eThickness of myometrium between gestation sac and the bladder (mm)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 155px;\" align=\"left\"\u003e\n\u003cp\u003e13(31.71%)\u003c/p\u003e\n\u003cp\u003e6(14.63%)\u003c/p\u003e\n\u003cp\u003e26207\u0026thinsp;\u0026plusmn;\u0026thinsp;8492\u003c/p\u003e\n\u003cp\u003e3.49\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94\u003c/p\u003e\n\u003cp\u003e2.65\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 509px;\" colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026beta;-HCG\u0026thinsp;=\u0026thinsp;\u0026beta;-human chorionic gonadotropin; CS\u0026thinsp;=\u0026thinsp;cesarean section\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n\u003ch2\u003eHIFU ablation evaluation\u003c/h2\u003e\n\u003cp\u003eHIFU treatment was successfully carried out for all patients (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). One session of HIFU ablation therapy was performed for 29 patients (70.73%). The other 12 patients (29.27%) received 2 HIFU sessions. The average HIFU treatment time was 83 minutes. The median HIFU sonication time was 705 s. After HIFU ablation, no blood perfusion was found in the pregnancy tissue by contrast-enhanced ultrasound (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e,\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e). Simultaneously, we could not detect fetal cardiac activity. During HIFU ablation, all patients complained of pain in the sacra or lower abdomen. A 10-point scale was used, and the pain score ranged from 1 to 3 points. The pain was relieved within 1 week without any special medical treatment. A hot skin sensation was complained of by fourteen patients. However, we found no skin burns in those patients.\u003c/p\u003e\n\u003ctable border=\"1\"\u003e\u003ccaption\u003e\n\u003cp\u003e\u0026nbsp;Table 2\u003c/p\u003e\n\u003cp\u003eThe treatment results\u003c/p\u003e\n\u003c/caption\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 373px;\"\u003e\n\u003cp\u003e\u003cstrong\u003eVariables\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 170px;\"\u003e\n\u003cp\u003e\u003cstrong\u003evalue\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 373px;\"\u003e\n\u003cp\u003e\u003cstrong\u003eHIFU\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp; Median treatment time(min)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp; Median sonication time(s)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp; Session of HIFU ablation\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026nbsp;1\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026nbsp;2\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSuction curettage \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp; The uterus cavity depth(cm)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp; Surgical time(min)\u003c/p\u003e\n\u003cp\u003eBlood loss during curettage (ml)\u003c/p\u003e\n\u003cp\u003eTreatments for bleeding during suction curettage\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026nbsp;No hemostasis (n)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026nbsp;Foley catheter balloon used (n)\u003c/p\u003e\n\u003cp\u003eSession of suction curettage\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; 1\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; 2\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFollow up\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp;\u0026nbsp; \u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 170px;\"\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e83(60, 132)\u003c/p\u003e\n\u003cp\u003e705 (614,1142)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e29(70.73%)\u003c/p\u003e\n\u003cp\u003e12(29.27%)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e9.64\u0026plusmn;1.43\u003c/p\u003e\n\u003cp\u003e35.45\u0026plusmn;10.23\u003c/p\u003e\n\u003cp\u003e99 (30, 240)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e29(70.73%)\u003c/p\u003e\n\u003cp\u003e12(29.27%)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e38(92.68%)\u003c/p\u003e\n\u003cp\u003e3 (7.32%)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 373px;\"\u003e\n\u003cp\u003eDuration of vaginal bleeding post-curettage (days)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 170px;\"\u003e\n\u003cp\u003e9.72\u0026plusmn;3.92\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 373px;\"\u003e\n\u003cp\u003eTime of menstruation recovery(days)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 170px;\"\u003e\n\u003cp\u003e29.38\u0026plusmn;3.34\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 373px;\"\u003e\n\u003cp\u003eTime for serum \u0026beta;-HCG normalization(days)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 170px;\"\u003e\n\u003cp\u003e23.18\u0026plusmn;3.13\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 543px;\" colspan=\"2\"\u003e\n\u003cp\u003e\u0026beta;-HCG=\u0026beta;-human chorionic gonadotropin\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab3\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eComparison of characteristics of exogenous CSP patients in two groups\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eVariables\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eThe bleeding group(n\u0026thinsp;=\u0026thinsp;12)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eThe control group (n\u0026thinsp;=\u0026thinsp;29)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eMaternal age(years)\u003c/p\u003e\n\u003cp\u003eBMI\u003c/p\u003e\n\u003cp\u003eGestational age\u003c/p\u003e\n\u003cp\u003eNumber of previous CS (n)\u003c/p\u003e\n\u003cp\u003eTime Interval since last CS(m)\u003c/p\u003e\n\u003cp\u003ePre-treatment serum \u0026beta;-HCG (mIU/mL)\u003c/p\u003e\n\u003cp\u003eGestational sac diameter (mm)\u003c/p\u003e\n\u003cp\u003eThickness of myometrium (mm)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e30(24, 41)\u003c/p\u003e\n\u003cp\u003e23.45\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;3.45\u003c/p\u003e\n\u003cp\u003e51.23\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;4.25\u003c/p\u003e\n\u003cp\u003e2(1\u0026ndash;3)\u003c/p\u003e\n\u003cp\u003e42(25, 89)\u003c/p\u003e\n\u003cp\u003e27148\u0026thinsp;\u0026plusmn;\u0026thinsp;6746\u003c/p\u003e\n\u003cp\u003e3.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.87\u003c/p\u003e\n\u003cp\u003e2.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e29(25, 38)\u003c/p\u003e\n\u003cp\u003e22.87\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;2.13\u003c/p\u003e\n\u003cp\u003e49.83\u0026thinsp;\u003cem\u003e\u0026plusmn;\u003c/em\u003e\u0026thinsp;5.15\u003c/p\u003e\n\u003cp\u003e2(1\u0026ndash;3)\u003c/p\u003e\n\u003cp\u003e37(19, 82\u003cem\u003e)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e25864\u0026thinsp;\u0026plusmn;\u0026thinsp;8769\u003c/p\u003e\n\u003cp\u003e3.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.77\u003c/p\u003e\n\u003cp\u003e2.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.75\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e0.453\u003c/p\u003e\n\u003cp\u003e0.367\u003c/p\u003e\n\u003cp\u003e0.312\u003c/p\u003e\n\u003cp\u003e0.419\u003c/p\u003e\n\u003cp\u003e0.187\u003c/p\u003e\n\u003cp\u003e0.328\u003c/p\u003e\n\u003cp\u003e0.019\u003c/p\u003e\n\u003cp\u003e0.014\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026beta;-HCG\u0026thinsp;=\u0026thinsp;\u0026beta;-human chorionic gonadotropin;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eCS\u0026thinsp;=\u0026thinsp;cesarean section\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd colspan=\"2\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003eSuction curettage assessment and follow-up\u003c/h2\u003e\n\u003cp\u003eSuction curettage was performed on all patients after HIFU treatment (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). No patient was converted to laparoscopy or hysterectomy. The median blood loss during suction curettage was 99 ml. We inserted the No. 14 Foley catheter balloon into the intrauterine cavity to manage massive vaginal bleeding (\u0026gt;\u0026thinsp;200 ml) in 12 patients. The catheter balloon was removed 24 hours later. Ultrasound checks were performed by an ultrasound specialist for every patient one week after suction curettage. The pregnancy tissues were successfully removed in 38 patients (92.68%). Three patients (7.32%) received a second session of suction curettage with blood loss of 20 ml for remnant pregnancy tissues.\u003c/p\u003e\n\u003cp\u003eAll patients received follow-up through clinical visits. The median period of vaginal bleeding was 9.72\u0026thinsp;\u0026plusmn;\u0026thinsp;3.92 days. The mean time for \u0026beta;-HCG normalization was 23.18\u0026thinsp;\u0026plusmn;\u0026thinsp;3.13 days. The average time of menstruation recovery was 29.38\u0026thinsp;\u0026plusmn;\u0026thinsp;3.34 days (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). No complications occurred during the follow-up period.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n\u003ch2\u003eAnalysis of risk factors for blood loss during suction curettage\u003c/h2\u003e\n\u003cp\u003eBased on the use of catheter balloons during suction curettage, 41 patients were divided into two groups. The patients who used catheter balloons were considered the bleeding group (blood loss\u0026thinsp;\u0026gt;\u0026thinsp;200 ml). The other patients were grouped into the control group. Between the two groups, we found no significant difference in terms of age, BMI, gestational age, number of previous cesarean sections, time interval from the last cesarean section, or \u0026beta;-HCG level before treatment (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). However, the size of gestational sac in the bleeding group (3.80\u0026thinsp;\u0026plusmn;\u0026thinsp;0.87 cm) was larger than that in the control group (3.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.77 cm) (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). The thickness of the interval myometrium between the bladder and gestational sac in the bleeding group (2.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89 mm) was less than that in the control group (2.75\u0026thinsp;\u0026plusmn;\u0026thinsp;0.75 mm) (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). In all exogenous CSP patients, there was a positive correlation between the size of the gestational sac and blood loss during suction curettage (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.401, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01). Meanwhile, the thickness of the interval myometrium between the bladder and gestational sac had a negative correlation with blood loss during suction curettage (\u003cem\u003er\u003c/em\u003e = -0.423, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo our knowledge, this is the first report on the use of HIFU combined with suction curettage for treating exogenous CSP. The success rate in this study was 92.68% and no patient was converted to laparoscopy or hysterectomy. The median intraoperative blood loss during suction curettage was 99 ml. The average time for serum β-HCG level normalization was 23.18\u0026thinsp;\u0026plusmn;\u0026thinsp;3.13 days, and the median time for menstruation recovery was 29.38\u0026thinsp;\u0026plusmn;\u0026thinsp;3.34 days. Although there are some deficiencies in HCG levels and menstrual recovery compared with those after laparoscopy [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], our protocol provides the possibility of one conservative treatment for exogenous CSP patients. We also reviewed the literature about the treatment of UAE combined with suction curettage for CSP. Introspective blood loss ranged from 14 ml to 114 ml, and serum β-HCG returned to normal levels within 15 to 29 days [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Our study obtained the similar results as those from the treatment of UAE combined with suction curettage and avoided the complications of UAE.\u003c/p\u003e \u003cp\u003eTheoretically, HIFU mainly uses high intensity ultrasound to focus on the internal target of the body in vitro. We speculate that HIFU contributes to the treatment of exogenous CSP in three ways. First, HIFU ablation can cause necrosis of the corresponding lesion cells. Through the mechanical effect of high intensity ultrasound, the high-temperature thermal effect formed an instantaneous high temperature\u0026thinsp;\u0026gt;\u0026thinsp;60℃, which led to necrosis in the pregnancy tissue. Second, the cavitation effect of HIFU could loosen the adhesion between the myometrium at the uterine scar and the gestational sac, which would be helpful for removing the pregnancy tissue [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Finally, HIFU has been reported to be used for the ablation of small vessels with a diameter\u0026thinsp;\u0026lt;\u0026thinsp;2 mm [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The thermal energy deposited in the pregnancy tissue can destroy small blood vessels. As seen on color Doppler assessment, the blood perfusion in the pregnancy tissue disappeared. For the reasons mentioned above, HIFU could make suction curettage a smoother process for removing the pregnancy tissue and reduce the risk of heavy hemorrhage. As reported before, adverse effects, such as sciatic and lower abdominal pain, injury to the bowel and bladder, fever, and skin burns, occur during HIFU ablation [\u003cspan additionalcitationids=\"CR33\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. In the ablation for exogenous CSP, the target site was located at the anterior wall of the cervix, which was located away from the bowl in the pelvic cavity. Ablation began from the innermost part, which was not near the bladder. With simultaneous ultrasound monitoring, HIFU ablation in our study caused no damage to surrounding organs. Although all patients complained of abdominal or sacral pain during the HIFU ablation, no patients needed further treatment.\u003c/p\u003e \u003cp\u003eDue to the characteristics of exogenous CSP, there is a risk of uterine perforation and substantial hemorrhage during suction curettage. To avoid uterine perforation during suction curettage, we first carried out vacuum suction. If an ultrasound check showed residual tissue, curettage was performed very gently. In our study, no uterine perforations occurred. A previous study reported that perforation of the uterus occurred in a CSP patient during suction curettage after HIFU ablation [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. The author attributed this event to the 2 mm thickness of the interval myometrium between the bladder and gestation sac. In our study, the thickness of the thinnest interval myometrium was 1.5 mm, but no uterine perforation occurred. Therefore, we deduce that uterine perforation is a result of comprehensive factors. For patients with bleeding greater than 200 ml, we used a Foley balloon catheter to compress the hemorrhage, which avoided the possibility of conversion to laparotomy. However, there were still 3 patients who had to undergo a second suction curettage. We found that all three of these patients were administered Foley balloon catheters during the suction curettage. Thus, the suction curettage was interrupted, which resulted in residual pregnancy tissue.\u003c/p\u003e \u003cp\u003eWe also found that the size of the gestational sac and the thickness of the interval myometrium between the bladder and gestational sac were correlated with blood loss during suction curettage. Our results were consistent with those of previous studies [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. Adhesion between the myometrium at the uterine scar and the gestational sac will form bleeding wounds as the pregnancy tissue is removed [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. The wound will expand with the increase in the gestational sac, which also elevates the risk of hemorrhage. The weakness of the myometrium is accompanied by poor contractility, which makes it difficult to close the bleeding vessels [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. We also found no significant difference in terms of age, BMI, gestational age, interval time from last CS, or β-HCG level before treatment between the two groups. We noticed that a previous study considered the β-HCG level to be a risk factor for massive hemorrhage [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]. As a biochemical index representing trophoblastic cell activity, the β-HCG level of exogenous CSP may not be high due to the muscular layer defects and insufficiency of the blood supply. The inconsistency might result from the different grouping standards adopted in different studies.\u003c/p\u003e \u003cp\u003eIn conclusion, our results indicate that HIFU combined with suction curettage is effective and safe in the treatment of exogenous CSP of \u0026lt;\u0026thinsp;9 weeks. We also found that the size of the gestational sac and the thickness of the interval myometrium between the bladder and gestational sac might be high-risk factors for blood loss during this treatment. Limited by the retrospective analysis and the sample number, we should validate our findings by carrying out prospective and large-scale multicenter studies in the future.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCompeting interests:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflicts of interest and nothing to disclose.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was sponsored by Zhejiang Provincial Public Welfare Technology Application Research Project in China. (LGF18H040006)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInstitutional Review Board approval waiving informed consent was obtained for this retrospective study (2021-0458).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLin Mu: Project development, data collection and manuscript writing. HF Weng: Data collection and management. XY Wang: Data analysis.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eTimor-Tritsch IE, Monteagudo A, Santos R, et al. (2012) The diagnosis, treatment, and follow-up of cesarean scar pregnancy. Am J Obstet Gynecol 207:44.e1-13. https://doi.org/\u003ca href=\"https://doi.org/10.1016/j.ajog.2012.04.018\"\u003e10.1016/j.ajog.2012.04.018\u003c/a\u003e\u003c/li\u003e\n \u003cli\u003eLiu D, Yang M, Wu Q. 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(2018) Sepsis after uterine artery embolization-assisted termination of pregnancy with complete placenta previa: A case report. J Int Med Res 46:546\u0026ndash;50. https://doi.org/10.1177/0300060517723257.\u003c/li\u003e\n \u003cli\u003eMallick R,Okojie A, Ajala T. (2016) Rectal perforation: Anunusual complication of uterine artery embolisation. J Obstet Gynaecol 36:867-868. https://doi.org/10.1080/01443615.2016.1180506.\u003c/li\u003e\n \u003cli\u003eKaump GR, Spies JB. (2013) The impact of uterine artery embolization on ovarian function. J Vasc Interv Radiol 24:459\u0026ndash;467. https://doi.org/10.1016/j.jvir.2012.12.002.\u003c/li\u003e\n \u003cli\u003eSavic LJ, Lin MD, Duran R,, et al. (2015) Three-dimensional quantitative assessment of lesion response to MR-guided high-intensity focused ultrasound treatment of uterine fibroids. Acad Radiol. 22(9):1199\u0026ndash;1205. https://doi.org/10.1016/j.acra.2015.05.008.\u003c/li\u003e\n \u003cli\u003eLiu X, Wang W, Wang Y, Wang Y, Li Q, Tang J. (2016) Clinical predictors of long-term success in ultrasound-guided high-intensity focused ultrasound ablation treatment for adenomyosis: a retrospective study. Medicine. 95(3):e2443. https://doi.org/10.1097/MD.0000000000002443.\u003c/li\u003e\n \u003cli\u003eHong Y, Guo Q, Pu Y, Lu D, Hu M. (2017) Outcome of high-intensity focused ultrasound and uterine artery embolization in the treatment and management of cesarean scar pregnancy: A retrospective study. Medicine (Baltimore). 96(30):e7687. https://doi.org/10.1097/MD.0000000000007687.\u003c/li\u003e\n \u003cli\u003eGodin PA, Bassil S, Donnez J. (1997) An ectopic pregnancy developing in a previous caesarean section scar. Fertil Steril. 67:398-400. https://doi.org/10.1016/S0015-0282(97)81930-9.\u003c/li\u003e\n \u003cli\u003eZhang C, Zhang Y, He J, Zhang L. (2019) Outcomes of subsequent pregnancies in patients following treatment of cesarean scar pregnancy with high intensity focused ultrasound followed by ultrasound-guided dilation and curettage. Int J Hyperthermia. 36(1):926-931. https://doi.org/10.1080/02656736.2019.1654619.\u003c/li\u003e\n \u003cli\u003eChen L, Xiao S, Zhu X, He S, Xue M. (2019) Analysis of the Reproductive Outcome of Patients with Cesarean Scar Pregnancy Treated by High-Intensity Focused Ultrasound and Uterine Artery Embolization: A Retrospective Cohort Study. J Minim Invasive Gynecol. 26(5):883-890. https://doi.org/10.1016/j.jmig.2018.09.001.\u003c/li\u003e\n \u003cli\u003eCopelan A, Hartman J, Chehab M, Venkatesan AM. (2015) High-Intensity focused ultrasound: current status for image-guided therapy. Semin Intervent Radiol. 32:398-415. https://doi.org/10.1055/s-0035-1564793.\u003c/li\u003e\n \u003cli\u003eWu F, Chen WZ, Bai J, et al. (2002) Tumor vessel destruction resulting from high-intensity focused ultrasound in patients with solid malignancies. Ultrasound Med Biol. 28:535-542. https://doi.org/10.1016/s0301-5629(01)00515-4.\u003c/li\u003e\n \u003cli\u003eHaar GT, Coussios C. (2007) High intensity focused ultrasound: physical principles and devices. Int J Hyperthermia 23:89-104. https://doi.org/10.1080/02656730601186138.\u003c/li\u003e\n \u003cli\u003eShaw CJ, ter Haar GR, Rivens IH, et al. (2014) Pathophysiological mechanisms of high-intensity focused ultrasound-mediated vascular occlusion and relevance to non-invasive fetal surgery. J R Soc Interface 11:20140029. https://doi.org/10.1098/rsif.2014.0029.\u003c/li\u003e\n \u003cli\u003eStewart EA, Rabinovici J, Tempany CM, et al. (2006) Clinical outcomes of focused ultrasound surgery for the treatment of uterine fibroids. Fertil Steril 85:22-29. https://doi.org/10.1016/j.fertnstert.2005.04.072.\u003c/li\u003e\n \u003cli\u003eZhu X, Deng X, Wan Y, Xiao S, Huang J, et al. (2015) High-intensity focused ultrasound combined with suction curettage for the treatment of cesarean scar pregnancy Medicine94(18):e854. https://doi.org/10.1097/MD.0000000000000854.\u003c/li\u003e\n \u003cli\u003eZhang Y, Zhang Z, Liu X, Zhang L, Hong F, Lu M.Zhang Y, et al. (2021) Risk factors for massive hemorrhage during the treatment of cesarean scar pregnancy: a systematic review and meta-analysis Arch Gynecol Obstet. 303(2):321-328. https://doi.org/10.1007/s00404-020-05877-9.\u003c/li\u003e\n \u003cli\u003eZhang Y, Zhang C, He J, Bai J, Zhang L.Zhang Y, et al. (2018) The impact of gestational sac size on the effectiveness and safety of high intensity focused ultrasound combined with ultrasound-guided suction curettage treatment for caesarean scar pregnancy Int J Hyperthermia. 35(1):291-297. https://doi.org/10.1080/02656736.2018.1496485.\u003c/li\u003e\n \u003cli\u003eLe A, Li M, Xu YH et al. (2019) Different surgical approaches to 313 cesarean scar pregnancies. J Minim Invasive Gynecol 26: 148-152. https://doi.org/10.1016/j.jmig.2018.03.035.\u003c/li\u003e\n \u003cli\u003eShao MJ, Hu MX, Xu XJ et al (2013) Management of caesarean scar pregnancies using an intrauterine or abdominal approach based on the myometrial thickness between the gestational mass and the bladder wall. Gynecol Obs Invest 76:151\u0026ndash;157. https://doi.org/10.1016/j.ejogrb.2019.04.008.\u003c/li\u003e\n \u003cli\u003eMa Y, Shao M, Shao X, et al, (2017) Analysis of risk factors for ntraoperative hemorrhage of cesarean scar pregnancy. Medicine 96(25):e7327．https://doi.org/10.1097/MD.0000000000007327.\u003c/li\u003e\n \u003cli\u003eFang Q, Sun L, Tang Y et al (2017) Quantitative risk assessment to guide the treatment of cesarean scar pregnancy. Int J Gynaecol Obs 139:78\u0026ndash;83. https://doi.org/10.1002/ijgo.12240.\u003c/li\u003e\n\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":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Exogenous cesarean scar pregnancy, High intensity focused ultrasound, Suction curettage, High-risk factors","lastPublishedDoi":"10.21203/rs.3.rs-740249/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-740249/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eTo evaluate the effectiveness of high intensity focused ultrasound (HIFU) combined with suction curettage in the treatment of exogenous cesarean scar pregnancy (CSP).\u003cstrong\u003e \u003c/strong\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e A total of 41 patients diagnosed with exogenous CSP were enrolled in this study. All patients received HIFU treatment combined with suction curettage. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eTwenty-nine patients were administered one session of HIFU ablation. In addition, the other 12 patients received 2 HIFU sessions. Suction curettage was performed in all patients after HIFU, and no patient was converted to laparoscopy or hysterectomy. The mean blood loss during suction curettage was 99 ml. Three patients received two sessions of suction curettage. The success rate of our study was 92.68%. The mean time for serum β-HCG normalization was 23.18±3.13 days. The average menstruation recovery time was 29.38±3.34 days. Based on the blood loss during suction curettage, 41 patients were divided into a bleeding group and a control group. The size of the gestational sac in the bleeding group (3.80±0.87 cm) was larger than that in the control group (3.39±0.77 cm) (\u003cem\u003eP\u003c/em\u003e \u0026lt;0.05). The thickness of the myometrium between the bladder and gestational sac in the bleeding group (2.37±0.89 mm) was less than that in the control group (2.75±0.75 mm) (\u003cem\u003eP\u003c/em\u003e \u0026lt;0.05). \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e The results suggested that HIFU combined with suction curettage could be considered an effective treatment for exogenous CSP of \u0026lt; 9 weeks. The size of the gestational sac and the thickness of the myometrium\u003cstrong\u003e \u003c/strong\u003ebetween the bladder and gestational sac might be high-risk factors for blood loss during this treatment.\u003c/p\u003e","manuscriptTitle":"Evaluation of the Treatment of High Intensity Focused Ultrasound Combined With Suction Curettage for Exogenous Cesarean Scar Pregnancy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-12-08 15:50:51","doi":"10.21203/rs.3.rs-740249/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2021-12-07T15:20:02+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2021-12-07T08:32:51+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Archives of Gynecology and Obstetrics","date":"2021-08-05T14:09:47+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2021-07-22T07:42:14+00:00","index":"","fulltext":""},{"type":"submitted","content":"Archives of Gynecology and Obstetrics","date":"2021-07-21T08:35:26+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"archives-of-gynecology-and-obstetrics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"arch","sideBox":"Learn more about [Archives of Gynecology and Obstetrics](https://www.springer.com/journal/404)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/arch/default.aspx","title":"Archives of Gynecology and Obstetrics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"20574b06-502a-4722-b525-7014728f6ab5","owner":[],"postedDate":"December 8th, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":9027090,"name":"Obstetrics \u0026 Gynecology"}],"tags":[],"updatedAt":"2022-03-28T20:02:35+00:00","versionOfRecord":{"articleIdentity":"rs-740249","link":"https://doi.org/10.1007/s00404-022-06487-3","journal":{"identity":"archives-of-gynecology-and-obstetrics","isVorOnly":false,"title":"Archives of Gynecology and Obstetrics"},"publishedOn":"2022-03-18 20:02:35","publishedOnDateReadable":"March 18th, 2022"},"versionCreatedAt":"2021-12-08 15:50:51","video":"","vorDoi":"10.1007/s00404-022-06487-3","vorDoiUrl":"https://doi.org/10.1007/s00404-022-06487-3","workflowStages":[]},"version":"v1","identity":"rs-740249","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-740249","identity":"rs-740249","version":["v1"]},"buildId":"oE6Zbj460LM0Up2FdVbMZ","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}