Urethral compliance in hypospadias operated by tubularized incised urethral plate (TIP) with and without a dorsal inlay graft: an experimental controlled study

Localization of external urethral orifice in coronary sulcus during urethroplasty in case of severe hypospadias accompanied by prostatic utricle cyst

BACKGROUND

To explore whether opening the external urethral orifice in the coronal sulcus can reduce the incidence of epididymitis after operating on hypospadias with prostatic utricle cyst (PUC) connecting to the vas deferens. Group A consisted of 3 patients with severe hypospadias and PUC undergoing cystostomy, hypospadias correction and urethroplasty, along with the relocation of the external orifice of the urethra to the coronal sulcus. Group B consisted of 4 patients having initial hypospadias repaired with meatus in the orthotopic position in the glans, presenting with multiple epididymitis after hypospadias surgery and unsuccessful conservative treatment. MR confirmed that all the Group B patients had PUC connecting to the vas deferens. Group B patients underwent urethral dilatation along with urethral catheterization, cutting of the original corpus cavernosum that encapsulated the urethra, and extension of the position of the external urethral orifice to the coronal sulcus.

RESULTS

In group A, 3 children underwent bladder fistula removal 2 weeks after the operation. The penis developed normally without any complications. Four children in group B underwent stent removal 12 weeks after operation, and one patient was still stenosed and dilated again. All patients in group B were followed without epididymitis recurrence.

CONCLUSIONS

For patients with hypospadias complicating with a PUC, connecting to one side of the vas deferens, the positioning of the external urethral orifice in the coronary sulcus would be helpful to reduce the occurrence of epididymitis.

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.

Effects of spongioplasty on neourethral function following hypospadias repair: an experimental study in rabbits

Purpose:

Spongioplasty (mobilization and midline approximation of the two branches of the bifid dysplastic distal corpus spongiosum) can form a covering layer for the neourethra to prevent urethrocutaneous fistula in hypospadias repair surgery. However, it remains unclear whether spongioplasty affects neourethral function. The objective of this study was to compare neourethral function after hypospadias repair with and without spongioplasty.

Materials and Methods:

Fourteen congenital hypospadiac New Zealand male rabbits were randomly allocated into two groups, seven animals underwent Duplay hypospadias repair and spongioplasty (experimental group), while seven underwent Duplay surgery alone (control group). Functional differences between groups were assessed by comparing neourethral compliance and flow rate. Two months after surgery, in vivo neourethral compliance was assessed by measuring intraluminal pressure with a digital pressure meter of an isolated neourethral segment, following progressive distension with 1, 2, and 3mL of air. Penises were harvested for uroflowmetry test using a simple device.

Results:

Postoperatively, fistula developed in one and zero rabbits in the control and experimental groups, respectively. Mean pressures tended to be higher in the experimental group than in the control group (82.14 vs. 69.57, 188.43 vs. 143.26, and 244.71 vs. 186.29mmHg for 1, 2, and 3mL of air, respectively), but the difference was not statistically significant. Mean flow rates also did not significantly differ between the experimental and control groups (2.93mL/s vs. 3.31mL/s).

Conclusion:

In this congenital rabbit model, no obvious functional differences were found between reconstructed urethras after hypospadias repair with and without spongioplasty.

Tubularised incised-plate versus tubularisation of an intact and laterally augmented plate for hypospadias repair: A prospective randomised study

OBJECTIVES

To compare the outcome of hypospadias repair using tubularised incised-plate (TIP) urethroplasty and tubularisation of an intact and laterally augmented urethral plate.

PATIENTS AND METHODS

This prospective randomised study included 370 patients with primary distal hypospadias. All had urethral plate widths of 8-10 mm and a glans of ⩾15 mm. Exclusion criteria were previous repair, circumcision, a wide urethral plate of >10 mm or a narrow plate of <8 mm in diameter, a small glans of <15 mm in diameter, chordee of >30°, and hormonal stimulation. Patients were randomised into two groups: Group 1 (185 patients) underwent TIP urethroplasty and Group 2 (185 patients) underwent tubularisation of the intact plate with lateral augmentation of the urethral plate using penile skin. The follow-up period was 12-28 months.

RESULTS

There were 172 evaluable patients in Group 1 and 177 in Group 2. The urethroplasty was successful in 83.2% and 94.4% in Groups 1 and 2, respectively. Complications occurred in 16.8% in Group 1 and 5.6% in Group 2 (P = 0.001). Meatal stenosis occurred in 7% and 3.4% in Groups 1 and 2, respectively (P = 0.130). There were statistically significant differences in the wound dehiscence, fistula, and re-operation rates of Group 1 versus Group 2, at 6% versus 0%, 9.8% versus 2.8%, and 13.4% versus 5.6%, respectively. The presence of mild chordee did not affect the complication rate (P = 0.242). The mean (SD) operative time was 56.7 (8.9) min in Group 1 and 93.7 (8.3) min in Group 2 (P < 0.001).

CONCLUSION

The outcome of tubularised intact and laterally augmented plate is better than classical TIP urethroplasty of hypospadias. Further trials are mandatory to extend the indications of the technique.

Urethral plate grafting improves the results of tubularized incised plate urethroplasty in primary hypospadias

OBJECTIVE

We conducted a competitive efficacy trial in order to examine whether grafting the raw area of the urethral plate (UP) with inner preputial skin in children with primary hypospadias (PH) during tubularized incised plate urethroplasty (TIP) improves the results of the operation.

MATERIAL AND METHODS

Fifty consecutive patients with pathology ranging from glanular to proximal penile PH were randomized into two groups, comparable for age and pathology, to be operated on either with TIP or a grafted TIP (G-TIP) procedure. Three patients failed the re-examination protocol, so the TIP group comprised 23 children aged 9.0 months-9.6 years (mean age 3.4 years) and the G-TIP group comprised 24 children, aged 10.0 months-9.4 years (mean 3.5 years). The patients were followed up for a period of 2-5 years (mean 3.2 years).

RESULTS

Within the TIP group, we observed the development of fistula with concomitant neourethral stenosis in two cases (8.7%), stenosis without fistula in four (17.4%), and glans dehiscence in one case (4.35%). Within the G-TIP group there was one case of fistula without stenosis (4.16%), no case of neourethral stenosis, and one case of glans dehiscence (4.16%). Two cases of non-slit-like meatus were observed in the TIP group. The results show that the complications of neourethral stenosis are significantly reduced (p < 0.05) in the G-TIP group, as is the total number of complications and unsatisfactory results. The duration of the TIP operation was 72-110 (mean 92) min, and for the G-TIP 100-136 (mean 115) min. No postoperative symptoms were observed that could be attributed to prolonged anesthesia time.

CONCLUSION

UP grafting with inner preputial skin, when added to the TIP procedure in the treatment of PH, results in a significantly smaller number of unsatisfactory results, and particularly fewer cases of neourethral stenosis. G-TIP can be used as the procedure of choice in PH patients.

Reduced flow after tubularized incised plate urethroplasty--increased fibrogenesis, elastin fiber loss or neither?

PURPOSE

Low urinary flow rates are common after tubularized incised plate urethroplasty but the etiology remains unclear and may be related to low urethral compliance due to abnormal collagen concentrations and/or fewer elastic fibers in the healed urethral plate. We hypothesized that inserting a preputial mucosal graft over the dorsal raw area after the midline incision may avoid scarring and improve urethral compliance.

MATERIALS AND METHODS

Adult rabbits were submitted to tubularized incised plate urethroplasty with or without inlay preputial graft according to a previously described protocol. Tissular concentrations of collagens I, III, IV, VI, VIII and XIII were measured. Histomorphometric analysis was used to quantify elastic fibers in the urethra. Tubularized incised plate urethroplasty with and without inlay preputial graft was compared to normal rabbit urethras (controls).

RESULTS

mRNA concentrations for collagens I, II and XIII were similar between controls and operated rabbits. The proportions between collagens I and III were 1.05, 0.87 and 1.21, respectively, in controls and animals undergoing tubularized incised plate urethroplasty with and without inlay preputial graft. mRNA concentrations for collagen IV and collagens VI/VIII tended to be higher and lower, respectively, in the operated urethras, despite showing statistical significance only for collagen VIII in animals undergoing tubularized incised plate urethroplasty with inlay preputial graft vs controls (p=0.02). The operated animals did not demonstrate a reduced number of elastic fibers in the urethral tissues compared to controls.

CONCLUSIONS

Elastic fiber number and distribution were similar between tubularized incised plate urethroplasty cases and controls, suggesting that decreased concentrations of elastic fibers do not explain the reduced urethral compliance after tubularized incised plate urethroplasty. The raw area determined by the dorsal urethral incision regenerated after standard tubularized incised plate urethroplasty, while cicatrization with fibrosis occurred in correspondence to the grafted areas after tubularized incised plate urethroplasty with inlay preputial graft.