Dorsal Onlay Oral Mucosa (DOOM) Urethroplasty for Post-Hypospadias Stricture

Lip mucosa grafted dorsally onto the urethra cut stricture recurrence to 4.5% over a median 6-year follow-up in 22 boys

Journal: Journal of Pediatric Urology | Published: 2026-02-04 | Type: Retrospective case series | PMID: 41734657 Authors: Babu Ramesh, Shajini Nirmalan (Department of Paediatric Urology, Sri Ramachandra Institute of Higher Education & Research, Chennai) Funding/COI: Funding not listed; no conflicts of interest declared

Summary

Post-hypospadias urethral stricture is a recognized late complication of hypospadias repair, and reconstructing these strictures in pediatric patients is technically demanding. Ramesh and Nirmalan describe a single-institution technique — dorsal onlay of oral mucosa harvested from the lower lip — applied in 22 boys over a decade. Peak urinary flow rate improved more than threefold after the procedure, and only one patient required any retreatment. The acronym DOOM is doing heavy lifting; the technique itself is a recognized variant of buccal mucosal urethroplasty.

Claims

• Qmax improved from a mean of 3.1 mL/s preoperatively to 10.2 mL/s postoperatively (p < 0.05)
• Stricture recurrence: 1/22 (4.5%), managed with optical internal urethrotomy (OIU)
• No fistula, diverticulum, or repeat open procedure required in any patient
• Donor-site morbidity (mild discomfort, transient tightness) resolved spontaneously in all cases
• Parental penile perception score (PPPS) rated excellent in 95% of cases
• Mean stricture length: 2.5 cm; median follow-up: 6 years (range 4–14 years)
• Patient cohort: median age 12 years (range 9–15)

Study Quality

This is a single-center retrospective case series of 22 patients — the weakest study design on the evidence hierarchy. There is no control group, no randomization, and no comparison arm (e.g., ventral onlay or two-stage repair). The primary flow outcome uses a paired pre/post design with a reported p-value, which is appropriate for this study type, but without a comparison group the relative contribution of the dorsal orientation versus oral mucosa grafting in general cannot be separated. "Parental penile perception score" is a subjective parent-reported instrument; its validation status and what it actually measures are not described in the abstract.

Follow-up duration is a genuine strength — a median of 6 years with a 14-year maximum is unusually long for a pediatric surgical series, and late stricture recurrence is a real concern in hypospadias reconstruction.

Red Flags

• n = 22 over 10 years from a single center; generalizability is limited and the series may not reflect the full spectrum of post-hypospadias stricture complexity
• No description of the original hypospadias repairs — proximal vs. distal, prior number of procedures, and type of initial repair are likely confounders that go unaddressed
• Funding source is not listed; cannot assess whether institutional or industry interests influenced the framing
• "PPPS" (parental penile perception score) is parent-reported and the validation basis is not cited — it captures parental satisfaction, not patient outcomes
• No urodynamic data beyond Qmax; whether voiding pressure, residual volume, or downstream complications were tracked is unclear
• All cases performed by, presumably, two surgeons at one high-volume pediatric urology center — reproducibility outside expert hands is uncharacterized

Strengths

• Long median follow-up (6 years) with a maximum of 14 years, meaningful for a pediatric cohort where complications emerge slowly
• Consistent technique across the series permits a coherent assessment of the specific procedure
• No fistula or diverticulum in any patient is a clinically meaningful zero-complication result
• Donor-site morbidity (lower lip) appears minimal and self-resolving, addressing a common concern about oral mucosal harvest in children

Verdict

A clean technical report from an experienced team, but it is evidence-base scaffolding, not evidence. Twenty-two cases over ten years at a single center cannot establish efficacy or safety beyond "this is feasible and the authors have not seen catastrophic failures." The Qmax improvement is real and statistically significant, and a 4.5% recurrence rate over six years is respectable — but without a comparison group, this number describes a population, not the technique's advantage. The paper is worth reading for surgeons looking to understand the dorsal onlay approach in pediatric post-hypospadias stricture; it is not a practice-changing study.