Comparisons of preoperative patient characteristics are shown in Table . The most frequent primary indication for benign hysterectomy among these patients was abnormal uterine bleeding in RALH (50%) and LAVH (36%) and fibroids in LSH (39%). Endometriosis was the third most frequent indication, ranging from 8% in RALH patients to almost 21% in LSH cases. The age range of all patients was 23–78 years. Those who underwent LSH were younger on average than either RALH (P = 0.067) or LAVH (P = 0.006) patients by 1.5 and 2.5 years, respectively, not surprising given the desire for a cervix-preserving procedure. Differences in gravidity and parity followed similar trends, with RALH patients having had significantly fewer pregnancies and live births than either LAVH or LSH patients, with no differences between those in the LAVH and LSH groups. Means for BMI indicate that many patients were obese (BMI ≥ 30) or bordering on obesity. Differences in BMI by approach were small, and comparisons were not statistically significant. A large proportion of patients had undergone prior abdominopelvic surgery, with RALH patients exhibiting the highest percentage (83.1%), which was significantly greater than that in patients who underwent LAVH (73.2%; P = 0.01). Patients who underwent LSH did not differ from the other groups with respect to prior surgery. Comparisons of preoperative characteristics between LAVH patients of Drs. Giep versus the other nine surgeons show very similar baseline profiles, with almost identical mean ages (42.6 vs. 42.4 years, respectively) and very similar mean BMI (29.9 vs. 29.5 kg/m2, respectively) and proportion with prior abdominopelvic surgeries (75.2 vs. 70.0%). These findings provide reassurance that patients from the two groups of surgeons combined as one LAVH cohort were very similar.
Preoperative characteristics by minimally invasive approach to hysterectomy
Examination of intraoperative characteristics by approach indicates that concomitant procedures were more often performed with RALH (in 50.6% of surgeries) than with either LAVH (in 26%) or LSH (in 20.6%; Table ). Specifically, the proportion of patients who had surgical procedures for endometriosis or lysis of adhesions was significantly greater in the RALH group than in the LAVH (P < 0.001) or LSH (P < 0.001) groups. Similar findings were evident for pelvic reconstruction (RALH vs. LAVH P = 0.012, RALH vs. LSH P < 0.001). Most pelvic reconstruction involved robotically assisted uterosacral fixation, anterior and posterior repair and pubovaginal sling with cystoscopy. These procedures would be expected to contribute to an increase in operative time. Although the rates of pelvic reconstruction were low in both LAVH and LSH, they were statistically higher in LAVH (4.9%) than LSH (3.4%; P = 0.04). Uterine weights ranged from 24 to 1,233 g. The mean uterine weight was similar in LAVH and LSH patients but differed significantly from that of RALH cases who had the largest uteri (207.4 ± 194.5 (RALH) vs. 149.6 ± 118.7 (LAVH) g, P < .001; vs. 141.1 ± 172.5 (LSH) g, P = 0.005]. The percentage of patients with uteri of at least 250 g was 23.2% in RALH compared to 9.1 and 8.0% in LAVH (P < 0.001) and LSH (P = 0.004), respectively. However, mean skin-to-skin operative time was 35 min longer for LAVH patients compared to both RALH and LSH patients for whom procedures took approximately 1.5 h on average (both comparisons, P < 0.001). Similarly, estimated blood loss was highest in LAVH, being over 100 ml greater than in RALH and LSH (both comparisons, P < 0.001). Length of hospital stay was short for all approaches, but significantly shorter for RALH patients than either LAVH (P < 0.001) or LSH (P = 0.022) patients.
Intraoperative and perioperative characteristics by minimally invasive approach to hysterectomy
The rates of conversion to an open procedure were low, ranging from zero to 1.7%, and did not differ by surgical approach (Table ). The conversions in the RALH group occurred early in the learning curve. Two conversions were within the first 25 cases and another two within the first 150 cases. These occurred in patients with large uteri where there was difficulty in accessing the blood vessels. Similarly, one conversion in the LAVH group occurred in a patient with a 16-week uterus where it was difficult to maintain hemostasis while proceeding laparoscopically. This patient was subsequently converted to an abdominal hysterectomy. Rates of intraoperative and postoperative complications within 30 days of surgery were low across the three surgical approaches: the overall rates totaled 3.8% for RALH, 1.9% for LAVH and 2.3% for LSH, with the majority being minor in severity. No statistically significant differences were noted by surgical method. In both the RALH and LAVH cohorts, there was one intraoperative cystotomy repair with no further sequelae. There were also two patients with incisional infections and one with a bacterial infection in the RALH cohort; these were treated with antibiotics during their hospital stay. One patient in the robotic cohort and one in the LAVH cohort experienced a pelvic abscess that was subsequently drained and treated. There were no instances of cuff dehiscence requiring repair in any of the cohorts. There was one patient in the robotic group who was treated for cuff cellulitis, and two patients reported bleeding from the vaginal cuff in the RALH and LAVH cohorts. Both of these latter complications were resolved without the need for reintervention. During the perioperative period, one patient in the robotic group suffered a pulmonary embolism that was treated by anticoagulation with heparin and then enoxaparin (Lovenox). Atelectasis was noted in three patients, one from the LAVH cohort and two in the LSH cohort.
Comparisons of perioperative characteristics for the LAVH procedures performed by Drs. Giep versus the other surgeons show similar patient uterine weights (153.4 ± 124.5 vs. 147.0 ± 114.4 g, respectively), EBL (157.3 ± 111.4 vs. 173.6 ± 163.3 ml, respectively) and length of hospital stay (1.1 vs. 1.2 days, respectively). However, operative time was significantly shorter for procedures performed by Drs. Giep given their extensive experience with laparoscopic procedures (101.5 ± 39.7 vs. 138.9 ± 48.4; P < .001).
Multivariable linear regression was used to identify those characteristics of the patients and the approach that were significant predictors of skin-to-skin operative time. The characteristics considered included patient age (dichotomized above or below the median age = 41 years), obesity (BMI <30, ≥30), previous abdominal or pelvic surgery, uterine weight (<250 g, ≥250 g), any concomitant procedure beyond hysterectomy with salpingo-oophorectomy and approach to surgery (RALH, LAVH, LSH). Younger age (P < 0.001), BMI <30 (P = 0.02), uterine weight <250 g (P < 0.001) and surgery other than LAVH (P < 0.001) were all independently associated with shorter operative times (data not shown). On average, the operative times were longer for older patients versus younger ones (21 min), for obese patients versus non-obese patients (8 min), for greater uterine weight patients versus those with a smaller uterus (24 min) and for those undergoing LAVH surgeries vs. those undergoing LSH and RALH (35 min).
Data points, representing the means of 25 sequential patients, were generated for skin-to-skin times, uterine weights and EBL over the entire case series for the RALH patients and for the comparable 100 LAVH patients whose procedures were performed by the same surgeons (HG, BG). Comparisons of the first 25 cases to the last showed no statistically significant differences for any of the LAVH parameters, although uterine weights generally increased with longer surgical experience (data not shown). Similar findings were evident in RALH for uterine weight and EBL (comparison of first and last data points, P = 0.189 and P = 0.875, respectively). However, operative skin-to-skin time significantly decreased with surgical experience (comparison of first 25 to last 37 patients, P = 0.003, Fig. ). The first 25 RALH patients had a mean operative time of 106.4 min, which is comparable to that of the LAVH procedures (101.5 min) and significantly different from the last patients’ operative time of 76.5 min. Furthermore, as suggested by the regression analyses above, operative time varied with changes in uterine weight over time (Fig. ).
Fig. 1 Learning curve for robotic-assisted laparoscopic hysterectomy (RALH). Solid black line connects the mean skin-to-skin operative times at 25-case intervals for RALH (P = 0.003 for mean of first 25 vs. last 37 patients). Dashed black line (more ...)