12: The impact of surgeon volume on perioperative adverse events in women undergoing minimally invasive hysterectomy for large uteri

Abstract

To evaluate the impact of surgeon volume on perioperative adverse events in women undergoing minimally invasive hysterectomy (MIH) for uteri >250 grams. This is a retrospective cohort study of all women who underwent vaginal (VH), laparoscopic (TLH), laparoscopic-assisted vaginal (LAVH), or robotic-assisted laparoscopic hysterectomy (RH) between January 2014 and July 2016 at a tertiary care referral center. Hysterectomy was performed for the following indications: fibroids, pelvic pain, abnormal uterine bleeding, and prolapse. Women were excluded if there was a preoperative diagnosis of malignancy. Patients were identified by Current Procedural Terminology codes and the system-wide electronic medical record was queried for demographic and perioperative data. Perioperative adverse events were defined a priori and classified using the Clavien-Dindo scale. Surgeon volume was defined as the mean number of MIH cases performed per month by each surgeon during the study period. Seven hundred sixty-three patients met inclusion criteria: 416 (54.5%) TLH, 196 (25.7%) RH, 90 (11.8%) TVH, and 61 (8%) LAVH. Mean (±SD) age was 47 ± 6 years, and body mass index (BMI) was 31.1 ± 7.4 kg/m2. Sixty-six surgeons performed MIH for uteri >250 grams during the study period. The mean monthly case volume was 16.4 ± 7.2 cases, and the median MIH volume was 23 cases (range: 1–147 cases). The mean uterine weight was 522.8 ± 322.7 grams. The rate of postoperative adverse events >Dindo grade 2 was 17.8% (95% CI = 15.2-20.7); 2.2% (95% CI = 1.4-3.6) were grade 3 and 0.5% (95% CI = 0.7-1.4) grade 4; there were no grade 5 adverse events. The overall rate of intraoperative adverse events was 4.2% (95% CI = 2.9-5.9). The rate of conversion to laparotomy was 5.5% (95% CI = 4.0-7.4). There was no difference in adverse event rates between the routes of MIH cases (25.6% vs. 17.5% vs. 18.0% vs. 14.8%, p = 0.2). Women who experienced any adverse event compared to those who did not were more likely to be of Hispanic, Asian or “other” ethnicity, had higher intraoperative blood loss (EBL) and longer operating case time. In a logistic regression model controlling for age, BMI, uterine weight, operating time, history of laparotomy and parity, higher monthly MIH volume remained significantly associated with adverse events (adjOR = 1.14, 95% CI = 1.0-1.3, p = 0.01), as did higher EBL (adjOR = 1.4, 95% CI = 1.1-1.8, p = 0.006). When controlling for the same variables, higher monthly MIH case volume remained significantly associated with intraoperative complications (adjOR = 1.30, 95% CI = 1.0-1.6, p = 0.02) as well as higher EBL (adjOR = 3.1, 95% CI = 2.0-4.9, p < 0.001). Conversion from a minimally invasive approach to laparotomy was not associated with monthly MIH case volume; however, conversion was associated with higher EBL (adjOR = 2.9, 95% CI = 1.8-4.9) and heavier uteri (adjOR = 9.7, 95% CI = 3.9-23). The overall rate of serious adverse events associated with MIH for uteri >250 grams was low. Higher EBL and longer operative times were associated with higher perioperative adverse event rates. Higher monthly MIH case volume was associated with a higher rate of intra- and postoperative adverse events but was not associated with conversion to laparotomy.