Association between operative time and short-term postoperative complications following minimally invasive surgery for stage III-IV endometriosis

We analyzed 583 patients who underwent minimally invasive surgery for stage III–IV endometriosis. Baseline characteristics stratified by median operative time summarized in Table  1 . Patients with operative times greater than the median were older (37.3 vs. 34.9 years, p  < .001) and more likely to be of Asian ethnicity (21.8% vs. 13.1%, p  = .032). There were no significant differences between groups regarding BMI, smoking status, ASA classification, surgical history, or the distribution of preoperative symptoms. Medical comorbidities were comparable between groups, although patients with longer operative times had higher rates of anxiety (14.1% vs. 7.8%, p  = .017) and depression (12.1% vs. 7.2%, p  = .049). Table 1 Patient demographic and clinical characteristics prior to procedure Characteristic Operative time ≥ 149 min n  = 293 Operative time < 149 min n  = 290 p  value Age, years 37.32 ± 6.50 34.93 ± 6.19 < 0.001 Body mass index, kg/m2 25.49 ± 5.44 24.98 ± 5.86 0.283 Smoking status 5 (1.7) 5 (1.7) 1 Race 0.032 White 156 (53.2) 188 (64.8) Black 31 (10.6) 28 (9.7) Asian 64 (21.8) 38 (13.1) Other* 41 (14) 35 (12) Ethnicity 0.294 Hispanic/Latino 65 (22.2) 50 (17.2) Not Hispanic/Latino 226 (77.1) 238 (82.1) Insurance type 1 Private 286 (97.6) 284 (97.9) Medicaid/Medicare 5 (1.7) 5 (1.7) None/Self Pay 2 (0.7) 1 (0.3) ASA classification** 0.292 1 110 (37.5) 127 (43.8) 2 172 (58.7) 155 (53.4) 3 11 (3.8) 8 (2.8) History of abdominal surgery 101 (34.4) 69 (23.8) 0.005 Prior surgery for endometriosis 131 (44.7) 119 (41.0) 0.403 Parity 0.37 ± 0.77 0.16 ± 0.47 < 0.001 Medical comorbidities Anxiety 23 (7.8) 41 (14.1) 0.017 Depression 21 (7.2) 35 (12.1) 0.049 Diabetes 1 (0.3) 3 (1.0) 0.371 Hypertension 16 (5.5) 9 (3.1) 0.219 Coagulopathy 6 (2.0) 0 (0.0) 0.030 Presenting symptoms Dysmenorrhea 252 (86.0) 251 (86.6) 0.904 Dyspareunia 93 (31.7) 90 (31.0) 0.859 Gastrointestinal symptoms** 149 (50.9) 121 (41.7) 0.031 Urinary symptoms 91 (31.1) 83 (28.6) 0.528 Non-cyclic pelvic pain 105 (35.8) 105 (36.2) 0.931 Infertility 78 (26.6) 42 (14.5) < 0.001 Fatigue 20 (6.8) 10 (3.4) 0.09 Back pain 45 (15.4) 36 (12.4) 0.339 Thoracic symptoms 4 (1.4) 8 (2.8) 0.26 Asymptomatic*** 3 (1.0) 7 (2.4) 0.221 Other**** 3 (1.0) 9 (3.1) 0.088 Prior therapy Prior hormonal therapy for related symptoms 211 (72.0) 219 (75.5) 0.348 Prior pain medication for chronic pelvic pain 20 (6.8) 23 (7.9) 0.637 Preoperative anemia 10 (3.4) 9 (3.1) 1 Data are n (%) or mean ± SD *Other included: Non-Hispanic American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other/Multiracial **ASA classifications: American Society of Anesthesiologists ***Gastrointestinal symptoms: dyschezia, diarrhea, constipation, bloating, nausea ****Other cyclic abdominal wall pain or lower extremities DIE: deeply infiltrating endometriosis Patient demographic and clinical characteristics prior to procedure Data are n (%) or mean ± SD *Other included: Non-Hispanic American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other/Multiracial **ASA classifications: American Society of Anesthesiologists ***Gastrointestinal symptoms: dyschezia, diarrhea, constipation, bloating, nausea ****Other cyclic abdominal wall pain or lower extremities DIE: deeply infiltrating endometriosis Operative characteristics between of cases below and above the median operative time presented in Table  2 . Patients with longer operative times had a higher proportion of procedures classified as AAGL surgical complexity C or D. Longer operative times were associated with a higher frequency of complex procedures, including ureterolysis (87.0% vs. 57.9%, p  < .001), lysis of adhesions (66.9% vs. 51.4%, p  < .001), salpingectomy (42.3% vs. 17.9%, p  < .001), unilateral oophorectomy (10.6% vs. 3.1%, p  < .001), hysterectomy (19.8% vs. 9.3%, p  < .001), excision of bladder nodules (3.4% vs. 0%, p  < .001), bowel resection (3.4% vs. 0.3%, p  = .011), and appendectomy (47.1% vs. 33.8%, p  = .001). Robotic-assisted approaches were also more common (20.8% vs. 1.0%, p  < .001) and the majority of surgeries were performed by minimally invasive gynecologic surgery (MIGS) subspecialists. These patients had significantly higher estimated blood loss (88.0 mL vs. 32.4 mL, p  < .001). Table 2 Operative characteristics Characteristic Operative time ≥ 149 min n  = 293 Operative time < 149 min n  = 290 p  value Surgeon type < 0.001 MIGS subspecialist 285 (97.3%) 255 (87.9%) General gynecologist 6 (2%) 31 (10.7%) Gynecologic oncologist 2 (0.7%) 4 (1.4%) Surgical approach Laparoscopy 230 (78.5%) 287 (99%) < 0.001 Robotic assisted 61 (20.8%) 3 (1%) AAGL endometriosis Surgical complexity classification A Excision or desiccation of superficial implants 3 (1.0) 23 (7.9) < 0.001 B Cystectomy, Appendectomy or DIE excision 24 (8.2) 75 (25.9) C Excision of bowel or ureter adhesions Or Excision of bladder muscularis lesions 252 (86.0) 191 (65.9) D Bowel resection or Reimplantation/reanastomosis 14 (4.8) 1 (0.3) Surgical procedure Fulguration/ablation/coagulation of endometriosis 6 (2.0) 19 (6.6) 0.008 Drainage of Endometrioma 2 (0.7) 4 (1.4) 0.449 Ovarian cystectomy 167 (57.0) 149 (51.4) 0.184 Adhesiolysis 196 (66.9) 149 (51.4) < 0.001 Ureterolysis 255 (87.0) 168 (57.9) < 0.001 Excision of ureteral nodules 4 (1.4) 0 (0.0) 0.124 Excision of bladder nodules 10 (3.4) 0 (0.0) 0.002 Rectal shaving or disc excision 18 (6.1) 9 (3.1) 0.114 Bowel resection 10 (3.4) 1 (0.3) 0.011 Appendectomy 138 (47.1) 98 (33.8) 0.001 Myomectomy 94 (32.1) 59 (20.3) < 0.010 Hysterectomy 58 (19.8) 27 (9.3) < 0.001 Salpingectomy 124 (42.3) 52 (17.9) < 0.001 Unilateral Oophorectomy 31 (10.6) 9 (3.1) < 0.001 Bilateral Oophorectomy 12 (4.1) 8 (2.8) 0.496 Estimated blood loss, mL 88.04 ± 122.79 32.36 ± 35.72 < 0.001 Total surgery time, minutes 230.60 ± 84.28 105.08 ± 25.19 < 0.001 Total OR time 279.41 ± 90.37 147.91 ± 27.29 < 0.001 Data are n (%) or mean ± SD MIGS: minimally invasive gynecologic surgery Operative characteristics C Excision of bowel or ureter adhesions Or Excision of bladder muscularis lesions Data are n (%) or mean ± SD MIGS: minimally invasive gynecologic surgery Surgical outcomes in association to operative time, stratified by different thresholds (50th, 75th, and 90th percentiles), are presented in Tables  3 , 4 and 5 . Table 3 Surgical complications- comparison of groups above and below the 50 th percentile of operative time Characteristic Operative time > 50th percentile (149 min) n  = 290 Operative time < 50th percentile (149 min) n  = 293 p  value Readmission (30 days) 9 (3.1) 8 (2.8) 1 Total length of stay, hours 18.79 ± 23.34 9.55 ± 7.49 < 0.001 Overnight admission 60 (20.5) 15 (5.2) < 0.001 Post operative length of stay, hours 11.46 ± 22.61 4.45 ± 5.09 < 0.001 Any intraoperative complication* 8 (2.7) 1 (0.3) 0.038 Any post operative complication** 31 (10.6) 23 (7.9) 0.318 Any minor postoperative complication 25 (8.5) 15 (5.2) 0.140 Any major postoperative complication 6 (2.0) 8 (2.8) 0.601 Surgical complications- comparison of groups above and below the 50 th percentile of operative time Table 4 Surgical complications- comparison of groups above and below the 75 th percentile of operative time Characteristic Operative time > 75th percentile (206 min) n  = 435 Operative time < 75th percentile (206 min) n  = 148 Readmission (30 days) 2 (2.0) 14 (3.2) 0.580 Total length of stay, hours 24.68 ± 29.97 11.6 ± 8.9 < 0.001 Overnight admission 43 (29.1) 32 (7.4) < 0.001 Post operative length of stay, hours 16.38 ± 29.31 5.13 ± 7.45 < 0.001 Any intraoperative complication* 4 (2.7) 5 (1.1) 0.242 Any post operative complication** 9 (6.1) 45 (10.3) 0.141 Any minor postoperative complication 7 (4.7) 33 (7.6) 0.265 Any major postoperative complication 2 (1.4) 12 (2.8) 0.535 Surgical complications- comparison of groups above and below the 75 th percentile of operative time Table 5 Surgical complications- comparison of groups above and below the 90 th percentile of operative time Characteristic Operative time < 90th percentile (280 min) n  = 525 Operative time < 90th percentile (280 min) n  = 58 Readmission (30 days) 2 (3.4) 15 (2.9) 0.682 Total length of stay, hours 37.52 ± 38.98 10.64 ± 8.9 < 0.001 Overnight admission 28 (48.3) 47 (9.0) < 0.001 Post operative length of stay, hours 27.52 ± 38.68 5.13 ± 7.45 < 0.001 Any intraoperative complication* 3 (5.2) 6 (1.1) 0.051 Any post operative complication** 5 (8.6) 49 (9.3) 1 Any minor postoperative complication 3 (5.2) 37 (7.0) 0.787 Any major postoperative complication 2 (3.4) 12 (2.3) 0.641 Data are n (%) or mean ± SD *Any intraoperative complications: Blood loss > 1 L, Bowel injury, Cystotomy, Ureteral injury, Uterine perforation, Vascular injury **Any post operative complication: Minor: bleeding, blood transfusion, superficial surgical site infection, urinary tract infection, urinary retention, ileus, acute renal insufficiency, pneumonia. Major: pelvic abscess, vaginal cuff dehiscence, deep venous thromboembolism, bowel injury, reoperation, small bowel obstruction, septic shock, pulmonary embolism, myocardial infarction, stroke, death Surgical complications- comparison of groups above and below the 90 th percentile of operative time Data are n (%) or mean ± SD *Any intraoperative complications: Blood loss > 1 L, Bowel injury, Cystotomy, Ureteral injury, Uterine perforation, Vascular injury **Any post operative complication: Minor: bleeding, blood transfusion, superficial surgical site infection, urinary tract infection, urinary retention, ileus, acute renal insufficiency, pneumonia. Major: pelvic abscess, vaginal cuff dehiscence, deep venous thromboembolism, bowel injury, reoperation, small bowel obstruction, septic shock, pulmonary embolism, myocardial infarction, stroke, death Longer operative times were significantly associated with increased total and postoperative hospital length of stay across all thresholds (50th, 75th, and 90th percentiles, all p   280 min) had postoperative stays nearly six times longer than those below the threshold (27.5 vs. 5.1 h, p  < .001). Additionally, longer procedures were significantly associated with an increased likelihood of overnight hospital admission. There were no significant differences in 30-day hospital readmission rates between groups. These findings are further supported visually in Figs.  1 A– C . Fig. 1 ( A ) Surgical complications- univariate comparison of groups above and below the 50th percentile of operative time. ( B ) Surgical complications- univariate comparison of groups above and below the 75th percentile of operative time. ( C ) Surgical complications- univariate comparison of groups above and below the 90th percentile of operative time ( A ) Surgical complications- univariate comparison of groups above and below the 50th percentile of operative time. ( B ) Surgical complications- univariate comparison of groups above and below the 75th percentile of operative time. ( C ) Surgical complications- univariate comparison of groups above and below the 90th percentile of operative time Intraoperative complications were more common among patients above the 50th percentile for operative time (2.7% vs. 0.3%, p  = .038). However, this association was not significant at higher thresholds. Postoperative complication rates, whether minor, major, or overall, did not significantly differ across operative time groups. Complication rates according to operative time are presented in Table  6 . Specific intraoperative complications did not significantly differ between groups. The most common minor post operative complications included urinary tract infections and superficial surgical site infections, whereas major complications were dominated by pelvic abscesses. Table 6 Specific surgical complications Characteristic Operative time ≥ 149 min n  = 293 Operative time < 149 min n  = 290 p  value Minor intraoperative complication Blood loss 1 (0.3) 0 (0.0) 1 Vascular injury 2 (0.7) 0 (0.0) 1 Bowel injury 3 (1.0) 0 (0.0) 0.249 Cystotomy 0 (0.0) 1 (0.3) 0.497 Ureteral injury 2 (0.7) 0 (0.0) 0.499 Postoperative Complications Minor Complications Post operative bleeding 1 (0.3) 2 (0.7) 0.622 Blood transfusion 1 (0.3) 2 (0.7) 0.622 Superficial surgical site infection 3 (1.0) 1 (0.3) 0.624 Urinary tract infection 10 (3.4) 4 (1.4) 0.174 Urinary retention 4 (1.4) 3 (1.0) 1 Acute renal insufficiency 1 (0.3) 0 (0.0) 1 Ileus 1 (0.3) 0 (0.0) 1 Major Complications Pelvic Abscess 3 (1.0) 4 (1.4) 0.724 Sepsis 0 (0.0) 1 (0.3) 0.497 Vaginal cuff dehiscence 0 (0.0) 2 (0.7) 0.247 Urinary tract injury 0 (0.0) 1 (0.3) 0.497 Deep venous thromboembolism 1 (0.3) 0 (0.0) 1 Bowel injury 1 (0.3) 0 (0.0) 1 Small bowel obstruction 1 (0.3) 0 (0.0) 1 Reoperation 2 (0.7) 7 (2.4) 0.105 Data are n (%) Specific surgical complications Data are n (%) Results of the multivariable regression analysis assessing operative time as an independent predictor of postoperative complications are presented in Table  7 . Table 7 Multivariable regression analysis of the association of operative time and postoperative complications a Characteristic Adjusted Odds Ratio 95% Confidence Interval p  value Operative time median percentile (149 min) 1.10 (0.62-2.00) 0.727 Operative time > 75th percentile (206 min) 0.44 (0.20–0.94) 0.035 Operative time > 90th percentile (280 min) 0.78 (0.29–2.11) 0.619 Operative time, hours 0.93 (0.75–1.15) 0.512 a Adjusted for: surgical approach, bilateral oophorectomy, appendectomy, hysterectomy Multivariable regression analysis of the association of operative time and postoperative complications a a Adjusted for: surgical approach, bilateral oophorectomy, appendectomy, hysterectomy No significant associations were observed between operative time thresholds at the 50th or 90th percentiles, or any additional 60 min of operation, and the occurrence of postoperative complications. Interestingly, operative time above the 75th percentile was independently associated with a reduced risk of postoperative complications (aOR 0.44, 95% CI 0.20–0.94). These associations are visually illustrated in Fig.  2 A. Fig. 2 ( A ) Multivariable regression analysis of the association of operative time and postoperative complications. Adjusted for: surgical approach, bilateral oophorectomy, appendectomy, hysterectomy. ( B ) Multivariable regression analysis of the association of operative time and overnight hospital admission. Adjusted for: year of surgery, surgical approach, AAGL surgical complexity, estimated blood loss, end of surgery at 18:00 or later ( A ) Multivariable regression analysis of the association of operative time and postoperative complications. Adjusted for: surgical approach, bilateral oophorectomy, appendectomy, hysterectomy. ( B ) Multivariable regression analysis of the association of operative time and overnight hospital admission. Adjusted for: year of surgery, surgical approach, AAGL surgical complexity, estimated blood loss, end of surgery at 18:00 or later Results of the multivariable regression analysis assessing operative time and overnight hospital admission as independent predictors of prolonged hospital length of stay are presented in Table  8 . Table 8 Multivariable regression analysis of the association of operative time and overnight hospital admission a Characteristic Adjusted Odds Ratio 95% Confidence Interval p  value Operative time median percentile (149 min) 2.52 (1.24–5.12) 0.011 Operative time > 75th percentile (206 min) 2.81 (1.47–5.37) 0.002 Operative time > 90th percentile (280 min) 6.22 (2.76–14.01)  193 min b 3.28 (1.74–6.18) < 0.001 Operative time, hours c 1.64 (1.30–2.06) < 0.001 a Adjusted for: year of surgery, surgical approach, AAGL surgical complexity, estimated blood loss, end of surgery at 18:00 or later b Calculated optimal cut-off time using Youden’s J statistic C For each additional hour of operative time Multivariable regression analysis of the association of operative time and overnight hospital admission a a Adjusted for: year of surgery, surgical approach, AAGL surgical complexity, estimated blood loss, end of surgery at 18:00 or later b Calculated optimal cut-off time using Youden’s J statistic C For each additional hour of operative time Operative time was a consistent predictor of overnight hospital admission. Each additional hour of surgery increased the odds of overnight admission by 64% (aOR 1.64, 95% CI 1.30–2.06). This trend was significant across all percentile thresholds. These results are visually illustrated in Fig.  2 B. The optimal cut-off point for the association of operative time and risk of overnight stay was 193 min.

This retrospective cohort study included all patients who underwent surgical treatment for endometriosis at a high-volume tertiary care center in the United States between November 1, 2013, and October 31, 2023. A retrospective cohort design was chosen to analyze a large sample of available data on endometriosis surgeries performed over a 10-year period. We included patients aged 18 to 51 years with pathology-confirmed stage III–IV endometriosis, classified according to the AAGL system [ 9 , 20 ]. The upper age limit of 51 years was chosen to include only women of reproductive age and to minimize confounding from postmenopausal conditions, as 51 is the average age of natural menopause [ 21 ]. All diagnoses were based on histopathological confirmation by board-certified pathologists according to standard institutional protocols. Exclusion criteria included stage I-II disease, gynecologic malignancy (either suspected preoperatively or confirmed pathologically), and urgent/emergent cases, defined as surgeries performed within 24 h of presentation for acute symptoms, as determined by the attending gynecologic surgeon. Operative time was analyzed using percentile thresholds (50th: 149 min, 75th: 206 min, 90th: 280 min) and in 60-minute increments. Percentile cut-offs (50th, 75th, and 90th) were selected to capture progressively longer operative times, with higher percentiles reflecting durations that are clinically relevant thresholds where complication risk may increase. This stratification reflects thresholds commonly used in surgical literature to examine complication trends across operative duration. Additionally, 60-minute increments were included to provide clinically interpretable estimates of risk per hour, consistent with prior studies reporting outcomes per additional operative hour [ 22 – 24 ]. Same-day discharge is the institutional standard following minimally invasive surgery. Overnight admission is reserved for select cases such as bowel resection or significant comorbidities. For this study, overnight admission was defined as any hospital stay extending beyond midnight on the day of surgery, regardless of whether it was pre-planned or unplanned. The primary outcome was the association between operative time and the occurrence of any short-term postoperative complication, defined as events occurring within 30 days after surgery. Secondary outcomes included association between operative time and: (1) intraoperative complications, (2) minor postoperative complications, (3) major postoperative complications, and (4) overnight admission. Data were collected from the Electronic Information Systems Department and managed using REDCap electronic data capture tools. Data were extracted by trained research staff under the supervision of the principal investigator. A random sample was independently reviewed by the principal investigator to ensure accuracy. Baseline and preoperative variables included age, body mass index (BMI), smoking status, American Society of Anesthesiologists (ASA) classification, race and ethnicity, insurance type, coexisting medical conditions, parity, and prior abdominal or endometriosis-related surgeries. Additional clinical variables collected were presenting symptoms, prior hormonal therapy for endometriosis, prior use of pain medications for chronic pelvic pain, and the presence of preoperative anemia. In our division, hemoglobin level measurements are performed only in cases of suspected anemia (e.g. abnormal uterine bleeding). Therefore, cases without hemoglobin levels prior to surgery were categorized as normal. Intraoperative variables included: surgeon type (minimally invasive gynecologic surgeon MIGS, general gynecologist, or gynecologic oncologist), surgical approach (laparoscopy or robotic assisted). The AAGL 2021 Endometriosis surgical complexity score [ 9 ] was used to classify procedures from Level A to Level D, as detailed in Supplementary Table ( 1 ) Additional surgical procedures are summarized in Supplementary Table ( 2 ) Postoperative outcomes were classified as major or minor based on the Clavien-Dindo classification system [ 20 ]. Major postoperative complications included pelvic abscess, wound dehiscence (vaginal cuff dehiscence), bowel injury, pulmonary embolism, deep venous thromboembolism, cardiac arrest, myocardial infarction, small bowel obstruction, septic shock, stroke, reoperation, or death. Minor postoperative complications included blood transfusion, postoperative bleeding, superficial surgical site infection, urinary tract infection, urinary retention, ileus, acute renal insufficiency, and pneumonia. Intraoperative complications were defined as estimated blood loss greater than 1 L, bowel injury, cystotomy, ureteral injury, uterine perforation, or vascular injury. In addition to surgical complications, 30-day hospital readmission rates and lengths of stay were collected for all patients. Complications were categorized as one occurrence (“yes” or “no”) per patient, regardless of their number or type (e.g. minor or major). This study adhered to good clinical practice guidelines and was approved by the Institutional Review Board (IRB #00003475). Due to the retrospective nature of the study, a waiver for informed consent was granted due to the retrospective study design. All data were de-identified and securely managed using REDCap electronic data capture tools hosted at our institution. Descriptive statistics were used to summarize patient demographic, clinical characteristics, operative and postoperative data. Categorical variables were analyzed using the Chi-square test or Fisher’s exact test as appropriate. For continuous variables, the student t-test was used. Results are reported as means (± standard deviation) for continuous variables and frequencies (percentages) for categorical variables. Multivariable logistic regressions were used to evaluate associations between operative time and both the primary outcome and overnight admission, adjusting for clinically relevant confounders identified in univariate analysis. Clinical relevance was determined based on variables identified in prior published studies as important predictors of perioperative outcomes in endometriosis surgery. The multivariable logistic regression analysis models included factors that reached a statistically significant difference in the univariate analysis and are clinically relevant. Collinearity among independent variables was assessed using variance inflation factor (VIF) analysis. A VIF value greater than 5 was considered indicative of potential multicollinearity. All predictors included in the final model demonstrated acceptable VIF values. To calculate the optimal inflection point for the association between operative time and overnight admission, Youden’s J Statistic was used. A post-hoc sample size analysis indicated that the cohort size had 80% power to detect a statistically significant increase from 7.9% postoperative complications rate in the  50th operative time group. Statistical analyses were performed using Software Package for Statistics and Simulation (IBM SPSS version 27, IBM Corp, Armonk, NY) and R (R Core Team 2021; R Foundation for Statistical Computing, Vienna Austria).

We found no evidence that longer operative time independently worsens short-term postoperative outcomes in advanced endometriosis surgery. Our findings reinforce the safety of complex, prolonged procedures for advanced endometriosis when performed in expert settings. This study supports the safety and feasibility of performing complex, meticulous procedures for advanced endometriosis without undue concern over prolonged operative duration alone. By rigorously adjusting for surgical complexity and employing standardized complication grading in a large, well-characterized cohort, our findings offer strong evidence to guide surgeons and inform patient counselling. Future research should aim to further explore strategies for minimizing the risks associated with prolonged surgeries and investigate lone term outcomes.

This study found that prolonged operative time in stage III–IV endometriosis surgery was not independently associated with increased short-term postoperative complications across multiple thresholds, though it was linked to higher intraoperative complication rates and overnight admissions. These findings suggest that, in high-volume specialized centers, longer procedures for advanced endometriosis may not necessarily translate into worse short-term outcomes when appropriate perioperative protocols and surgical expertise are in place. Studies in several surgical disciplines reported that prolonged operative time was associated with increased risk of postoperative complications [ 25 ]. In the context of gynecologic surgery and hysterectomy specifically, one study reported that longer operative time were associated with increased all 30-day complication rates across hysterectomy types [ 26 ]. However, that study included all routes of hysterectomy, did not account for concomitant procedures performed, and did not stratify complications by severity. Magrina et al. reported that operative time was the only independent predictor of postoperative complications in stage III–IV endometriosis surgery. Their study found that each additional 60 min of operative time was associated with 57% increased odds of postoperative complications [ 10 ]. However, only 14 postoperative complications were documented and the variables included in the multivariable regression analysis were not reported. Thus, it is unclear how these conclusions were drawn. Another study identified operative time as independent predictor of overall postoperative complications among patients undergoing surgery for deep infiltrating endometriosis [ 18 ]. However, that study was limited by a sample size of 165 patients only. Ratner et al. evaluated patients with all stages of endometriosis. They quantified the factors contributing to longer operative time and identified endometriosis stage and surgeon expertise as key predictors. When analysing risk factors for complications they found that operative time was not independently associated with any postoperative complications after adjusting for endometriosis stage​ [ 11 ]. Clark et al. conducted a study examining predictors of major complications following laparoscopic treatment of all endometriosis stages​. Although women with advanced endometriosis had longer operative times, that was not an independent predictor of major complications [ 14 ]​. Meyer et al. analyzed a large cohort of endometriosis cases across varying levels of surgical expertise to identify risk factors for major complications. While longer operative times were observed in patients with complications, operative time was not independently associated with major complications in multivariable analysis [ 6 ]. Importantly, the study could not stratify patients by endometriosis severity or surgical complexity, which limits direct comparison to cohorts specifically focused on advanced disease. Nonetheless, their results align with the concept that disease factors and surgical complexity expertise, rather than operative duration alone, are the primary drivers of postoperative risk. To summarize, overall, prior studies have shown conflicting evidence regarding whether longer operative time increases the risk of postoperative complications in endometriosis surgery. Smaller series and studies limited to deep infiltrating disease have often reported a significant association, whereas larger cohorts adjusting for disease severity and surgeon expertise generally did not identify operative time as an independent predictor. Our findings align with the latter, supporting the interpretation that surgical complexity and underlying disease burden are likely the primary drivers of risk, rather than operative duration alone. In relation to prior studies, our work overcomes several limitations by focusing exclusively on stage III–IV endometriosis classified using the AAGL surgical complexity system. We include a larger, well-characterized cohort, apply rigorous multivariable adjustment for confounders, and utilize standardized complication grading. These methodological improvements enable us to provide more precise and clinically relevant insights. Our finding may be explained by several factors. Surgeries were performed in a high-volume, specialized center. The vast majority was performed by surgeons with advanced expertise in endometriosis management, where operative complexity is anticipated and meticulously managed. Experienced surgeons often utilize meticulous intraoperative techniques and collaborate within multidisciplinary teams, which can mitigate the risk of complications. Standardized perioperative protocols, including anesthesia management and postoperative care pathways, likely contribute to buffering the risks traditionally associated with prolonged surgeries. Our study also showed that operative time exceeding the 75th percentile was associated with a reduced likelihood of postoperative complications. This unexpected inverse association may reflect improved outcomes in more carefully planned, multidisciplinary surgeries or higher surgeon experience in prolonged procedures. It is also possible that longer surgeries reflect greater attention to thorough disease excision, contributing to fewer complications postoperatively. Another parameter evaluated was intraoperative complications, which was associated with prolonged operative time. While intraoperative complications may prolong surgical time and increased postoperative complications [ 27 , 28 ], our results suggest that such complications, when promptly recognized and managed, do not necessarily translate to worse short-term postoperative outcomes. Beyond this direct observation, it is important to consider the indirect effects of intraoperative complications. These events can increase surgical complexity and prolong recovery by causing additional physiological stress or necessitating further interventions. Experienced surgeons can mitigate these risks through prompt recognition and management, thereby minimizing their impact on patient recovery and preventing further complications. One additional finding was an association between operative time, longer LOS, and overnight hospital admission. These findings align with previous studies [ 10 , 12 , 29 – 31 ]. A potential explanation for the association between prolonged operative time and extended hospital stay, despite the lack of increased postoperative complications, is that longer and more complex procedures, for example those involving bowel surgery, inherently require prolonged postoperative observation and pain management [ 32 , 33 ]. Additionally, prolonged anesthesia exposure can increase physiological effect thus delaying patient recovery and requiring extended observation [ 34 , 35 ]. While the regression model adjusted for multiple confounders, including surgeries concluding late, residual confounding may remain. Procedures performed by MIGS subspecialists and those utilizing robotic assistance were longer. This may reflect the selective use of robotic platforms for more complex cases, as well as the operative patterns of individual surgeons. In our cohort, the majority of robotic procedures were performed by a single specialist, which may have contributed to longer operative times. This is consistent with previous reports, where complex endometriosis cases resulted in prolonged operative duration [ 11 ]. Additionally, robotic-assisted surgery has been used for complex gynecological procedures to improve surgical precision. However, it has demonstrated significantly longer operative durations [ 36 ]. Our findings are reassuring for clinicians managing advanced endometriosis. They suggest that longer operative times, while associated with extended hospital stays, do not inherently worsen short-term postoperative outcomes when surgeries are performed in specialized centers. These findings support a clinical emphasis on surgical thoroughness rather than speed. In complex cases, prioritizing meticulous dissection even at the cost of extended operative time may improve patient outcomes without increasing short-term risk. The results present the importance of setting appropriate patient expectations regarding recovery. Referral to expert multidisciplinary centers, and the use of preoperative hormonal therapy, may further optimize outcomes by reducing surgical complexity and enhancing recovery [ 27 , 37 , 38 ]. Finally, anticipating surgeon fatigue during very prolonged cases and planning strategies such as staged procedures may help maintain surgical performance and patient safety. Although our findings suggest that prolonged operative time does not increase short-term complication rates in stage III–IV endometriosis surgery, further research is needed. Previous studies in stage I–II disease have shown no increase in complications with longer operative times across different levels of surgical expertise [ 30 ]. However, validation of these findings specifically in stage III–IV populations is recommended. Studies should also assess broader practice settings, including lower-volume centers, to confirm the generalizability of these results. Future research should explore long-term outcomes, such as pain recurrence, fertility, and late complications. Additionally, studies investigating strategies to manage surgeon fatigue and the role of preoperative therapies could further optimize outcomes in complex endometriosis surgery. This study has several strengths. To our knowledge, it is the first to specifically examine the impact of operative time on short-term outcomes within the AAGL stage III–IV endometriosis categories while also accounting for surgical complexity as defined within the classification system. By focusing on this high-complexity population, we minimized confounding related to disease severity and surgical expertise. Complications were graded using the validated Clavien–Dindo classification system, ensuring objective and standardized outcome assessment. Furthermore, the study was conducted at a single high-volume tertiary care center where all patients underwent minimally invasive surgery under standardized perioperative protocols, enhancing consistency across cases. Finally, we adjusted for concomitant procedures performed, limiting the confounding factors introduced. We acknowledge several limitations. First, as a retrospective study, there is potential for selection bias and unmeasured confounding. Although we adjusted for known variables, factors such as specific surgical techniques, assistance availability, anesthesia protocols, and intraoperative decision-making are difficult to fully capture. Second, as almost all surgeries were performed by highly experienced endometriosis specialists in a quaternary referral center with advanced resources and multidisciplinary support, our findings may not be generalizable to lower-volume centers or to surgeons with less specialized training. In lower-volume settings, longer operative times may still pose higher risks due to differences in surgeon experience and case volume, limited availability of multidisciplinary teams for complex cases, less familiarity with advanced minimally invasive techniques, reduced access to specialized anesthesia and perioperative care protocols, less advanced surgical equipment and technology, and potentially fewer institutional resources for postoperative monitoring and complication management. Third, the overall complication rate in our cohort was relatively low, which, while encouraging, may limit the statistical ability to detect small increases in risk. Forth, as longer operative times were not associated with increased risk of postoperative complications, a specific inflection point could not be identified. Lastly, we did not assess long-term outcomes such as chronic pain recurrence, fertility, or late complications, which could also be influenced by operative time.

Endometriosis is a chronic condition defined by the ectopic presence of endometrial like tissue outside the uterus [ 1 ]. It has a profound impact on quality of life, with patients experiencing significant physical, psychological, and social impairment [ 2 ]. In the USA, total direct costs are estimated at $12,118 per patient per year, while indirect costs reach approximately $15,737 per patient per year. Direct costs include inpatient and outpatient care, surgical procedures, medications, and other healthcare services, whereas indirect costs are primarily due to absenteeism and reduced productivity (presenteeism) [ 3 ]. It affects approximately 10% of reproductive-age women worldwide [ 4 ]. More than 65% of patients undergo an endometriosis-related surgical procedure within one year of their initial diagnosis [ 5 ], with major complications occurring in approximately 2.6% of cases following surgery [ 6 ]. Management strategies are individualized and depend on symptom severity, fertility goals, age and patient preferences, with surgical intervention reserved for severe or refractory cases [ 7 , 8 ]. The AAGL classification provides a standardized framework to quantify surgical complexity based on anatomical involvement and procedural difficulty, which is critical for understanding variations in surgical outcomes [ 9 ]. According to the AAGL 2021 surgical complexity classification, endometriosis surgeries are categorized by anatomical involvement and procedural difficulty, with stages III and IV indicating extensive disease. Stages III and IV represent advanced disease with significant pelvic distortion, often necessitating complex multi-organ procedures [ 9 ]. These complex procedures, often requiring concomitant interventions [ 10 ], are associated with prolonged operative times [ 11 , 12 ]. In general surgical populations, longer operative durations have been linked to increased postoperative morbidity, attributed to greater tissue trauma, blood loss, and extended anesthesia exposure [ 13 ]. Although operative time has been studied as a potential predictor of postoperative complications, data regarding the impact of operative time on short-term outcomes in stage III–IV endometriosis remain limited and inconsistent [ 10 , 14 ]. Some studies have identified prolonged operative time as a predictor of postoperative complications, whereas larger or more rigorous studies did not find operative time to be an independent risk factor after adjusting for disease severity and surgeon expertise. Moreover, most studies have not assessed operative time as an independent variable, but rather in combination with other factors [ 6 , 14 – 18 ]. Furthermore, few studies have specifically targeted patients with stage III–IV disease, as classified by the AAGL surgical complexity system. In the context of stage III–IV endometriosis surgery, the most clinically significant complications include major infections such as pelvic abscesses and surgical site infections, injuries to adjacent organs like the bowel, bladder, or ureter, and unplanned hospital readmissions. These events have the greatest impact on patient recovery and long-term health outcomes [ 19 ]. This study aimed to determine whether operative time is independently associated with short-term postoperative complications in patients with AAGL stage III–IV endometriosis undergoing surgery at a specialized center and to evaluate the relationship between operative duration and the likelihood of overnight hospital admission. Overnight hospital admission is typically reserved for cases involving unexpected complications or complex recovery and is associated with increased healthcare costs and patient burden. We hypothesized that longer operative time would be independently linked to a higher risk of short-term postoperative complications as well as increased likelihood of overnight admission. By clarifying these relationships, our study seeks to provide evidence that can inform surgical planning and help set realistic expectations for both patients and clinicians.

Below is the link to the electronic supplementary material. Supplementary Material 1 Supplementary Material 1