Effect of the depth and width of the urethral plate on tubularized incised plate urethroplasty

PURPOSE: We determined the effect of the depth and width of the urethral groove on tubularized incised plate urethroplasty for distal hypospadias. MATERIALS AND METHODS: We retrospectively reviewed the records of 48 patients who underwent tubularized incised plate urethroplasty for distal hypospadias between September 1996 and December 1998 for whom preoperative evaluation of the depth and width of the urethral groove was available. Patients were examined by an independent clinician a median of 28 months after surgery when the neourethra was calibrated and urinary stream assessed. RESULTS: Of the 48 patients 46 were available for clinical examination. The urinary stream was straight in 40 boys and angled in 8, while none sprayed. Urethral fistula developed in 6 patients with a urethral plate of less than 8 mm. wide (p = 0.001). The urethral groove was deep in 13 cases, moderate in 20 and shallow in 15. There were no differences among these 3 groups in regard to urinary stream direction or fistula rate. Of the boys with a shallow urethral groove 6 (40%) have a neourethral caliber of 6Fr or less versus 3 (15%) with a moderate and 0 with a deep groove. This difference was statistically significant (p = 0.028). Each patient in whom meatal stenosis developed had a shallow urethral groove. CONCLUSIONS: Urethral groove depth appears to influence neourethral caliber after tubularized incised plate urethroplasty. A shallow groove predisposes to a narrower neourethra and meatal stenosis subsequently. We observed no evidence that incising the urethral plate increases the final urethral diameter. Urethral fistula after tubularized incised plate urethroplasty was associated with an initially narrow urethral plate.