Can outcome of internal urethrotomy for short segment bulbar urethral stricture be predicted?

Purpose: We predicted the outcome of visual internal urethrotomy (VIU) by measuring the percentage of lumen narrowing at the stricture site on retrograde urethrography (RGU). Materials and Methods: From January 1991 to June 2002 patients with primary bulbar urethral strictures who underwent VIU were selected for the study. Patients with a history of intervention, complete block of the urethral lumen and stricture greater than 2 cm were excluded from study. Urethral diameter at the area of maximum stenosis and at the normal distal urethra was measured on RGU with Vernier caliper and percentage narrowing was derived. Patients were followed 3 times monthly with symptoms, calibration and whenever required with RGU. Recurrence of symptoms, failure to self-calibrate and the need for secondary procedure were considered treatment failure. Results: Complete followup data were available in 105 patients (44 grade 1 and 61 grade 2). Mean bulbar urethral stricture length was 0.86 cm. Inflammation was the cause of stricture in 83 (79%) and trauma the cause in 22 (21%) patients. In the Cox proportional hazards model only grade of narrowing had a significant impact on outcome. There were 41 cases of treatment failure in the total followup of 46 +/- 9 months. Mean recurrence-free duration +/- SD was 13 +/- 15 and 44.52 +/- 19 months in cases of treatment failure and success, respectively (p < 0.0001). Mean percentage narrowing was significantly higher with treatment failure (69.9% + 16.1% vs 48.55%. +/- 17.3%, p < 0.0001). A cutoff of 74% for urethral narrowing was derived to predict the outcome with 78% probability. Conclusions: Percentage narrowing of the urethral lumen at the stricture site is a useful predictor of VIU outcome.