Dorsal, ventral onlay for urethroplasty equivalent, study finds

Seattle-Findings from a retrospective review of patients undergoing single-stage bulbar urethroplasty with buccal mucosa suggest that neither dorsal nor ventral onlay of the graft is inherently superior.

Researchers from the University of Washington, Seattle analyzed data from all procedures performed by two experienced reconstructive surgeons from 2001 to 2011, excluding strictures involving pendulous urethra. The heterogeneous cohort included 41 men who underwent dorsal onlay and 62 who underwent ventral onlay. There were no significant differences between the two groups with respect to mean age, body mass index (BMI), stricture length, or graft size, nor with respect to stricture etiology or proportions of men with a history of diabetes or prior dilation. However, compared with the ventral onlay group, men with a dorsal onlay were more likely to have had prior urethroplasty (22% vs. 8%) and multiple direct vision internal urethrotomies (DVIUs, 49% vs. 32%), indicating those having a dorsal onlay had more complicated strictures, said first author Bradley Figler, MD, a fellow in trauma and reconstructive urology at the University of Washington.

Failure rate similar between groups

Median follow-up after the reconstruction was 14.7 months for the dorsal onlay group and 34.6 months for the ventral onlay group. Failure, defined as the need for endoscopic or open revision of the reconstruction or placement of a suprapubic catheter for urinary retention, occurred in six patients in the dorsal onlay group (15%) and in 12 patients in the ventral onlay group (19%). There was no statistically significant difference in failure rate between groups, and in both univariate and multivariate logistic regression analysis, graft position was not predictive of urethroplasty failure.

“Buccal musoca is generally well accepted as a graft material for bulbar urethroplasty, but it remains contentious whether dorsal or ventral placement of the graft is preferred,” said Dr. Figler, who presented the findings at the 2012 AUA annual meeting in Atlanta.

“Our data suggests that as long as patients are selected properly, dorsal and ventral onlay buccal mucosa grafting are equivalent. However, we acknowledge that selection bias is a potential limitation of our study, as there may be a tendency toward using the dorsal approach in more complicated cases. Prospective studies are necessary to determine the true efficacy of these approaches.”

Acknowledging the bias of the retrospective study, senior author Hunter Wessells, MD, commented that it has value in providing information for appropriately powering a prospective study.

“The failure rate in these procedures is relatively low so that no single institution could enroll a study population adequately powered to detect statistical significance between groups. The data from our study would be useful for performing the sample-size calculation for a multicenter study,” said Dr. Wessells, professor and chair of urology at the University of Washington.

The unadjusted logistic regression analysis showed that BMI, graft size, smoking status, stricture etiology, stricture length, and history of prior procedures were also not predictive of failure. However, there was a trend for diabetes to be associated with failure (p=.06), and in a multivariate logistic regression analysis adjusting for graft position, graft size, etiology, number of prior DVIUs, prior urethroplasty, prior dilation, and smoking status, diabetes significantly increased the likelihood of failure by 9-fold.

However, the possibility that diabetes is a risk factor for failure after single-stage bulbar urethroplasty with buccal mucosa must be considered carefully because the study population included only a limited number of men with diabetes (10%), Dr. Figler said.