Can a graft be placed over a flap in complex hypospadias surgery? An experimental study in rabbits

Outcome of spongioplasty alone as second layer of tubularised incised plate urethroplasty in patients with hypospadias

Background

Spongioplasty alone or in combination with local tissue flaps can be used as a second layer for the prevention of complications of tubularised incised plate urethroplasty (TIPU) of hypospadias repair. It can be used when wide urethral plate and well-developed robust spongiosum are present. This study aims to review the success rate and complications of TIPU performed utilising spongioplasty alone as a second layer in Type 3 well-developed robust spongiosum.

Methods

This is a retrospective observational study conducted between January 2015 and December 2019 at a tertiary care centre. A total of 21 patients aged 4–15.4 years with primary hypospadias having a Type 3 well-developed robust spongiosum, Glans score ≤ 2, Meatal score ≤ 4, and Shaft score ≤ 3 underwent TIPU using spongioplasty alone as a second layer. The hospital stay ranged from 10 to 14 days and follow-up from 12 to 36 months.

Results

Hypospadias was distal in 12 (57.1%), mid in 5 (23.8%), and proximal penile in 4 (19.1%) patients. The mean Glans Meatus Shaft score was 6.1 (G = 1.25, M = 2.95, S = 1.9) with a range of 3–9. An early post-operative complication of preputial oedema and bladder spasm developed in 1 (4.7%) patient each. Meatal stenosis developed in 1 (4.7%) patient. None developed urethrocutaneous fistula. At 3 months all patients had good urinary flow (> 15 ml/s) and good cosmesis. All the patients/parents (in case of minors) were satisfied with the result.

Conclusion

Spongioplasty alone as the second layer after TIPU for primary penile hypospadias in patients with well-developed robust spongiosal tissue is associated with minimal, easily manageable complications.

Preclinical Experiments for Hypospadias Surgery: Systematic Review and Quality Assessment

Background: There is a steadily growing number of different reconstructive surgical procedures for hypospadias that were tested on animal models prior to their human application. However, the clinical translatability and reproducibility of the results encountered in preclinical urethral reconstruction experiments is considered poor, with significant factors contributing to the poor design and reporting of animal experiments. Our objective was to evaluate the quality of the design and reporting in published articles of urethral reconstructive preclinical studies. Methods: Both PubMed and EMBASE databases were searched for animal urethral repair experiments between January 2014 and September 2019. Internal quality (bias) was evaluated through several signaling questions arising from the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE), while the quality of reporting was assessed by the Animal Research: Reporting of In vivo Experiments (ARRIVE) guidelines by scoring of a 20-item checklist. Results: A total of 638 articles were initially screened after the literature search. Employing the inclusion and exclusion criteria, 30 studies were chosen for full-text screening and 21 studies were considered eligible for the quality assessment. The mean score of the checklist was 66%. The elements that accomplished the highest grades included the number of animals utilized, the number in each investigational and control group, and the delineation of investigational conclusions. The items that were least commonly stated comprised information about the experimental method, housing and husbandry, rationalization of the number of animals, and reporting of adverse events. No paper stated the sample size estimation. Conclusion: We found that several critical experiment design principles were poorly reported, which hinders a rigorous appraisal of the scientific quality and reproducibility of the experiments. A comprehensive implementation of the ARRIVE guidelines in animal studies exploring urethral repair is necessary to facilitate the effective translation of preclinical research findings into clinical therapies.

Tubularized urethral reconstruction using a prevascularized capsular tissue prelaminated with buccal mucosa graft in a rabbit model

Tubularized graft urethroplasty fails largely because of inadequate graft take. Prefabrication of buccal mucosa lined flap has theoretical indications for constructing neourethra with an independent blood supply. The efficacy of using a tissue expander capsule as an induced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized urethral reconstruction in a rabbit model was tested. The experiments were performed in three stages. First, silicone tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Next, buccal mucosa grafts were transplanted to the newly formed capsular tissue supplied by the axial vessel for buccal mucosa-lined flap prefabrication. Then, circumferential urethral defects were created and repaired by buccal mucosa graft (Group 1), capsule flap (Group 2) and prefabricated capsule buccal mucosa composite flap (Group 3). With retrograde urethrography, no rabbits in Group 1 maintained a wide urethral caliber. In Group 2, the discontinued epithelial layer regenerated at 1 month, and the constructed neourethra narrowed even though the lumen surface formed intact urothelial cells at 3 months. In Group 3, buccal mucosa formed the lining in the neourethra and kept a wide urethral caliber for 3 months. The capsule may serve as an induced vascular bed for buccal mucosa-lined flap prefabrication. The prefabricated buccal mucosa-lined flap may serve as a neourethra flap for circumferential urethral replacement.

Correction of Residual Ventral Penile Curvature After Division of the Urethral Plate in the First Stage of a 2-Stage Proximal Hypospadias Repair

PURPOSE OF REVIEW

The first stage of a 2-stage proximal hypospadias repair involves division of the urethral plate and correction of any residual ventral penile curvature (VPC). Options to correct residual VPC include dorsal corporal shortening or ventral corporal lengthening techniques. This review discusses these options and suggests an approach to management.

RECENT FINDINGS

Recent reports of 2-stage proximal hypospadias repairs indicate low rates of recurrent VPC with either dorsal corporal shortening or ventral corporal lengthening. Dorsal corporal shortening with dorsal plication may be preferentially used for mild to moderate residual VPC after division of urethral plate and ventral corporal lengthening reserved for severe residual VPC. Ventral corporal lengthening with grafts has been associated with urethroplasty complications after the second stage hypospadias surgery. Ventral corporal lengthening with relaxing incisions of corpora has been reported, but concerns about adverse effects require longer term studies. Little guidance exists to choose the best technique for VPC correction during first stage hypospadias repair after division of urethral plate. Reported literature suggests good results with dorsal plication techniques and ventral corporal lengthening. A practical approach is to use dorsal plication techniques for mild to moderate residual VPC after division of urethral plate (<45°) and reserve ventral corporal lengthening for severe residual VPC (>45°).