Association between body mass index and pain following transobturator sling.

We aimed to prospectively evaluate the association between body mass index (BMI) and development of postoperative-onset pain in women undergoing transobturator midurethral sling procedures. We conducted a prospective, observational cohort study of women undergoing inside-to-out transobturator midurethral sling. At preoperative visit, height, weight, self-reported activity level and baseline pain were documented. At postoperative visits, patients indicated pain location and severity, procedure success, and satisfaction. We used log binomial regression to calculate risk ratios, controlling for potential confounders. For the 129 women included, median age was 50.0 years and BMI was 27.2 kg/m2. Adjusting for age and activity level, overweight and obese women had significantly increased risk of postoperative-onset pain compared to normal BMI women. Overweight women were at 1.70 (95%CI 1.05-2.75) times the risk compared to leaner counterparts, whereas obese women were at 1.76 times the risk (95%CI 1.04-2.89). Neither success nor satisfaction was associated with BMI. Impact statement Over three million midurethral slings have been placed worldwide for the treatment or prevention of stress urinary incontinence. The procedure has been studied in lean, overweight and obese populations, and found to have similar efficacy regardless of BMI. Similarly, the risks of midurethral sling have been well-documented, including the risk of pain after transobturator sling. Little attention has been given to whether this risk of postoperative pain varies based on patient BMI. Our previous work suggesting that leaner patients might be at increased risk of postoperative pain following transobturator sling was limited by the shortcomings of a retrospective study design. In this prospective study, we were able to adjust for age and activity level, finding that higher BMI women were at increased risk of postoperative pain, while reporting similar levels of satisfaction with the procedure. Future research is needed to find what differences in anatomy or physiology can explain this finding. From a clinical standpoint, thorough counselling of all patients but particularly those with elevated BMI, is required so that appropriate expectations regarding recovery can be set preoperatively.