Bladder perforation during tension-free vaginal tape procedures : Analysis of learning curve and risk factors

To estimate whether rates of bladder perforation decrease with increasing surgical experience. We performed a review of all patients undergoing a tension-free vaginal tape procedure performed by senior resident physicians under the guidance of a single surgeon. Physician experience was assessed by sequentially assigning case numbers to each procedure for each resident. For analysis of learning curve, cases were grouped in fives (ie, first five representing cases 1 to 5, second five cases 6 to 10). Twenty-three residents performed 278 procedures. The median number of cases performed was 13 (range 3 - 22); mean number was 12.1 (sd = +/- 5.6). The rate of perforation was 34.2% (95/278, 95% confidence interval 28.8-39.9%). Age and weight were significantly associated with perforation. The cystotomy group was, on average 4.5 years younger (P = .007) and 7.86 kg (17.3 lb) lighter (P < .001). Rate of injury in the first five series was 40.9%, 30.7% in second series of five, and 25.9% in the third series of five and was statistically significant (linear-by-linear association chi(2) = 4.286, df = 1, P = .038). The relationship between the incidence of cystotomy and the cumulative number of cases performed was inversely correlated. As the number of cases a resident completed increased, there was a slight tendency for cystotomy to decrease (P.033). On cystoscopic examination, residents missed 35 of the 95 injuries (37%, 95% confidence interval 27.8-46.9%). A learning curve exists for tension-free vaginal tape procedures. Many injuries are missed on initial resident cystoscopic inspection, highlighting the need for comprehensive cystoscopic training during residency. II-3.