Fact or myth? The long shared common wall between the fistula and the urethra in male anorectal malformation with urethral bulbar fistula

It has long been considered surgical dogma that the length of the shared common wall (CW) between a fistula and the urethra in males with anorectal malformation (ARM) and rectourethral bulbar fistula (RUBF) is considerably longer than in males with ARM and rectourethral prostatic fistula (RUPF). This belief has led surgeons who perform laparoscopic-assisted anorectoplasty (LAARP) for RUPF to avoid LAARP for RUBF for risk of potential injury to the urethra or incomplete removal of the fistula. In this study, we compared CW between RUBF and RUPF using distal colostography (DCG) and direct intraoperative measurements. DCG of rectourethral fistula patients (n = 63; RUBF: n = 44; RUPF: n = 19) were used to measure CW retrospectively. Results were expressed as a ratio of the height of L4; i.e., CW:L4. If less than 0.7, the CW was classified as being “short”; if 0.71–1.4, as being “medium”; and if greater than 1.41, as being “long”. CW that could not be measured was classified as indeterminate. 24 of these patients also had CW measured intraoperatively during LAARP as previously described. The results obtained using both techniques were also compared. Surprisingly, CW:L4 in RUBF patients was short in 47.7%, medium in 27.3%, long in 20.5%, and indeterminate in 4.5% on DCG, equivalent to mean lengths of 7 mm, 8.5 mm, and 10.3 mm obtained using direct intraoperative measurement for short, medium, and long CW:L4 categories, respectively. CW:L4 in RUPF was short in 73.6%, medium in 10.5%, and long in 5.2% on DCG, while mean intraoperative measurements were 5 mm, 7 mm, and 10 mm, respectively. Differences in CW measured intraoperatively were not significantly different between RUBF and RUPF (p = NS). From our findings, 47.7% of CWs in RUBF were short using two independent methods, with only 20.5% being long. Thus, LAARP should be considered actively for treating selected RUBF cases and not be excluded on the basis of CW length.