Narrow urethral plate augmentation in anterior and middle hypospadias repair: Onlay flap VS. Inlay graft. A prospective randomized comparative study

Abstract

The measurement of the urethral plate width (as an objective parameter) and its effect of this width on the results of tubularized incised plate urethroplasty (TIPU) have been reported in two series and both authors reported that a urethral plate width<8mm is associated with higher complication rates. The augmentation of the urethral plate either by dorsal inlay graft urethroplasty (DIGU) or Onlay flap has been compared with the original TIPU in different degrees of hypospadias with better surgical results in augmented cases. To evaluate the surgical results of longitudinal Onlay preputial flap (LOF) vs (DIGU) techniques in augmentation of the narrow urethral plate. Primary anterior and middle hypospadias cases with narrow urethral plates were randomly allocated into two groups; group one operated by DIGU and group two operated by (LOF). The Success rate, individual complication rate, and operative times were compared. 39 cases completed the study. No significant differences in patients' characteristics were detected. In the DIGU group, one case (5.3%) complicated with fistula and glandular dehiscence wherein in the LOF group, 7 cases (35%) Complicated with 5 fistulae, 2 glanular dehiscences, one flap loss, one diverticulum (p= .02). No significant differences in the rates of individual complications. Variables affecting the success of hypospadias repairs are many. Urethral plate quality is an important variable among these variables. The definition of urethral plate quality is usually subjective. In the DIGU group, only 1/19 (5.3%) case had two complications, fistula and glandular dehiscence. Mouravas etal., in their comparative study between TIPU and G-TIP without mention of urethral plate width reported a significant reduction of the overall complications and urethral stenosis without significant reduction in fistula rate. In their G-TIP group, only 2 cases out of 24 (8.3%) were complicated with one fistula and one glandular dehiscence where in the TIPU group, 7 cases (30.4%) were complicated with one glandular dehiscence and 6 cases with urethral stenosis. In the LOF group, fistula in 5/20 cases (25%) was the commonest complication followed by glandular dehiscence in 2 cases (10%). Diverticulum and flap loss occurred in one case for each (5%). In the multivariate analysis of 474 patients' cohort by Spinoit etal., there were no significant differences between the risk of re-intervention after TIP and Onlay flap in anterior and middle hypospadias (25.8% vs. 18.8%), and (22.2% vs. 20%) respectively. Our data suggest that augmentation of the narrow urethral plate with DIGU has a better surgical outcome than with LOF. No significant difference in cosmetic outcomes detected.