Urethral distortion after placement of synthetic mid urethral sling

Purpose: We retrospectively compared preoperative characteristics in patients with new onset lower urinary tract symptoms after receiving a mid urethral sling who did (group 1) and did not (group 2) have radiographically confirmed urethral distortion during voiding. Materials and Methods: After receiving institutional review board approval we reviewed the charts of patients who underwent mid urethral sling excision for new onset lower urinary tract symptoms between January 2003 and July 2009. We collected demographic and questionnaire data, including the Urogenital Distress Inventory, Incontinence Impact Questionnaire and visual analog scale (score 0 to 10) for quality of life, and preoperative urodynamics data, including maximum flow, detrusor pressure at maximum flow and post-void residual urine. Lateral voiding cystourethrogram was done with the patient standing. Results: Of 87 operable patients 23 were excluded from analysis due to lack of a voiding cystourethrogram (16) or of the voiding phase on voiding cystourethrogram (7). Groups 1 and 2 consisted of 51 and 13 patients, respectively. Age, time to sling excision, and Urogenital Distress Inventory, Incontinence Impact Questionnaire and quality of life scores were not significantly different between the groups. Preoperative urodynamic parameters in 37 group 1 and 7 group 2 patients revealed a mean detrusor pressure at maximum flow of 31.1 and 22.2 cm H₂O, respectively (p = 0.25). Mean preoperative maximum flow was 13.4 and 15.4 ml per second (p = 0.59), and median post-void residual urine was 45.5 and 8.3, ml respectively (p = 0.16). Conclusions: Despite similar baseline symptoms and uroflow characteristics patients with urethral distortion had 50% higher detrusor pressure and greater post-void residual urine than those without urethral distortion. Flow rate alone may be insufficient to predict the impact of the mid urethral sling on bladder function in patients with new onset lower urinary tract symptoms.