A Histomorphological Study of the Divergent Corpus Spongiosum Surrounding the Urethral Plate in Hypospadias

Topography-guided Anatomical Reassembly for Distal Penile Hypospadias Without Chordee: A Comprehensive Illustration and Midterm Results of a Novel Approach

OBJECTIVE

To provide a comprehensive illustration of the newly introduced "topography-guided anatomical reassembly" approach, which has shown promising early results, and to report the midterm outcomes of an extended series.

METHODS

This is a prospective cohort study of all patients presenting to the author's facility with distal penile hypospadias without chordee between June 2018 and January 2023. Redo cases, circumcised cases, and cases with non-preservable plates are excluded. The procedure follows the most recently introduced principle of the topography-guided anatomical reassembly approach for distal penile hypospadias, that is, the exclusive zipping-up of the unfolded spongiosal plate.

RESULTS

A subset of 97 boys met the enrollment criteria. The hypospadias meatus was coronal or sub-coronal in 35 boys, distal penile in 45 boys, and mid-penile in 17 boys. The mean age at the time of surgical correction was 8.11 months. The mean operative time was 66.7 minutes. After a mean follow-up of 27 months, 5 urethrocutaneous fistulae were reported as the following: 3 glanular and 2 sub-coronal. Meatal disfigurement with downward stream deviation was reported in 2 more patients. Two more occurrences of meatal recession were identified, yet surgical correction was not necessary. The overall reoperation rate settled at 7%.

CONCLUSION

The proposed topography-guided anatomical reassembly technique for distal hypospadias is simple, effective, and highly feasible at midterm follow-up of the given series. Maintaining the integrity of well-developed penile tissues eliminates the possibility of unforgivable tissue damage and avoids the need for challenging revision procedures.

Comparison of hypospadias phenotype pixel segmentation to GMS score

BACKGROUND

Hypospadias phenotype assessment determines if the anatomy is favorable for reconstruction. Glans-Urethral Meatus-Shaft (GMS) has been adopted in an effort to standardize hypospadias classification. While extremely subjective, GMS has been widely used to classify the severity of the phenotype to predict surgical outcomes. The use of digital image analysis has proven to be feasible and prior efforts by our team have demonstrated that machine learning algorithms can emulate an expert's assessment of the phenotype. Nonetheless, the creation of these image recognition algorithms is highly subjective. In order to reduce a subjective input in the evaluation of the phenotype, we propose a novel approach to analyze the anatomy using digital image pixel analysis and to compare the results using the GMS score. Our hypothesis is that pixel cluster segmentation can discriminate between favorable and unfavorable anatomy.

OBJECTIVE

To evaluate whether image segmentation and digital pixel analysis are able to analyze favorable vs unfavorable hypospadias anatomy in a less subjective manner than GMS score.

METHODS

A total of 148 patients with different types of hypospadias were classified by 1 of 5 independent experts following the GMS score into "favorable" (GG), "moderately favorable" (GM) and "unfavorable" (GP) glans. From there, 592 images were generated using digital image segmentation. 584 were included for final analysis due to certain images being excluded for poor image quality or inadequate capture of target anatomy. For each image, the region of interest was segmented separately by two evaluators into "glans," "urethral plate," "foreskin" and "periurethral plate". The values obtained for each segmented region using machine-learning statistical pixel k-means cluster analysis were analyzed and compared to the GMS score given to that image using an ANOVA analysis.

RESULTS

Analysis of image segmentation demonstrated that k-means pixel cluster analysis discriminated "favorable" vs "unfavorable" urethral plates. There was a significant difference between scores when comparing the GG and GM groups (p = 0.03) and GG and GP groups (p = 0.05). Pixel cluster analysis could not discriminate between "moderately favorable" and "unfavorable" urethral plates.

CONCLUSIONS

Through our analysis, we found significant pairwise difference for different tissue qualities. Digital image segmentation and statistical k-means cluster analysis can discriminate anatomical features in a similar way to the GMS score. Future research can target discerning between different tissue qualities in an effort to predict surgical outcomes for hypospadias repair.

One-stage repair of proximal hypospadias by in situ tubularization of the transverse preputial island flap

PURPOSE

This study aimed to compare the efficacy of modified transverse preputial island flap (TPIF) repair with the traditional TPIF procedure and Byar's two-stage procedure in proximal hypospadias repair, especially in the postoperative urethral stricture incidence rates.

MATERIALS AND METHODS

Patients admitted for proximal hypospadias treated with modified TPIF repair, the traditional TPIF procedure, or Byar's two-stage procedure at our institution from 2017 to 2021 were identified, and the incidence of postoperative complications among them was compared.

RESULTS

In total, 142 patients were included (modified TPIF group, 43; traditional TPIF group, 37; and Byar's two-stage group, 62). The length of the neourethra was 4.21 ± 0.63 cm in the modified TPIF group, 4.18 ± 0.71 cm in the traditional TPIF group, and 4.20 ± 0.68 cm in the Byar's two-stage group. The rate of urethral stricture in the modified TPIF group (two cases, 4.65%) was significantly lower than that in the traditional TPIF group (four cases, 10.81%) (P = 0.008). Seven (16.28%) cases of urethrocutaneous fistula occurred in the modified TPIF group, six (16.22%) in the traditional TPIF group, and eight (12.90%) in the two-stage group. Additionally, one case (2.33%) of urethral diverticulum occurred in the modified TPIF group, one (2.70%) in the traditional TPIF group, and three (4.84%) in Byar's two-stage group.

CONCLUSIONS

Modified TPIF repair can ensure a wedge anastomosis between the proximal urethral meatus and the neourethra, provide support and blood supply for the neourethra. Furthermore, it extended the urethral plate width at the anastomosis and urethral meatus, effectively reducing the incidence of urethral strictures.

Spongioplasty with Buck's fascia covering dorsal inlay graft urethroplasty for primary hypospadias repair

INTRODUCTION

Neourethral covering is an essential technique for preventing complications such as fistula and glans dehiscence in hypospadias repairs. The spongioplasty has been reported for neourethral coverage about 20 years ago. However, reports of the outcome are limited.

OBJECTIVE

This study aimed to retrospectively evaluate the short-term outcome of spongioplasty with Buck's fascia covering dorsal inlay graft urethroplasty (DIGU).

METHODS

From December 2019 to December 2020, 50 patients with primary hypospadias (median age at surgery, 37 months; range, 10 months-12 years) were treated by a single pediatric urologist. The patients underwent spongioplasty with Buck's fascia covering dorsal inlay graft urethroplasty in single stage. The penile length, glans width, urethral plate width and length, and the location of the meatus of the patients were recorded preoperatively. The patients were followed up,complications noted, and postoperative uroflowmetries at the one-year follow-up time were evaluated.

RESULTS

The average width of glans was 12.92 ± 1.86 mm. A minor penile curvature was observed in all patients (≤30°). The patients were followed up for 12-24 months, and 47 patients (94%) were free from complications. A neourethra formed with a slit-like meatus at the tip of the glans, and the urinary stream was straight. Three patients had coronal fistulae (3/50) and no glans dehiscence, and the mean ± SD Q_max of postoperative uroflowmetry was 8.13 ± 3.8 ml/s.

DISCUSSION

This study estimated the short-term outcome of the DIGU covered using spongioplasty with Buck's fascia as the second layer in patients diagnosed with primary hypospadias with a relatively small glans (average width <14 mm). However, only a few reports emphasize spongioplasty with Buck's fascia as the second layer and the DIGU procedure performed on a relatively small glans. The major limitations of this study were its short follow-up time and the retrospective data collection.

CONCLUSIONS

Dorsal inlay graft urethroplasty combined with spongioplasty with Buck's fascia as coverage is an effective procedure. In our study, this combination had good short-term outcomes for primary hypospadias repair.

Application of a free preputial tube graft coupled with urethral plate urethroplasty combined with a Buck's fascia integral covering for the single-stage repair of severe hypospadias

Objective

To assess the outcome of a free preputial tube graft coupled with urethral plate urethroplasty combined with a Buck's fascia integral covering (BFIC) for the single-stage repair of severe hypospadias in children.

Materials and methods

A retrospective study was performed on 40 children with hypospadias who were treated in our hospital from December 2017 to February 2022. The inclusion criteria were as follows: (1) the patient had proximal hypospadias, or penile curvature over 30° after degloving the penis; and (2) the patient underwent surgery for hypospadias for the first time. A free preputial tube graft coupled with urethral plate urethroplasty combined with a Buck's fascia integral covering was performed, and all patients were followed up for more than 6 months.

Results

After degloving the foreskin, the urethral orifice was retracted to the perineum and scrotum in 20 cases, penoscrotal in 8 cases, and penile in 12 cases. Single-stage repair was achieved without complications in 34 (85%) patients. The remaining six patients experienced postoperative complications: urethrocutaneous fistula occurred in five cases and glans dehiscence with urethrocutaneous fistula in one case. No urethral diverticulum occurred in any case. A neomeatus with a vertically oriented slit-like appearance was achieved at the tip of the glans in all cases, with one exception.

Conclusion

The single-stage operation with a free preputial tube graft coupled with urethral plate urethroplasty combined with a Buck's fascia integral covering in the treatment of severe hypospadias achieves favorable functional and cosmetic outcomes.

Phenotypic modulation of vascular smooth muscle cells in the corpus spongiosum surrounding the urethral plate in hypospadias

Hypospadias is an abnormal ventral development of the penis caused by incomplete virilization of the male genital tubercle. This study investigated the phenotypic modulation of vascular smooth muscle cells (VSMCs) in the corpus spongiosum surrounding the urethral plate in hypospadias. The urethral corpus spongiosum tissue was collected for HE, Masson and α-SMA immunohistochemical staining. Spongiosum VSMCs were cultured and identified by α-SMA fluorescence. qRT-PCR and Western blotting and fluorescence were performed. The results showed that the vascular lumen of the corpus spongiosum around the urethral plate was larger and that the vascular smooth muscle layer was thicker in hypospadias. The expression of the contractile markers α-SMA and Calponin 1 in VSMCs was decreased, the expression of the synthetic marker OPN was increased, and the transcription of the phenotypic switching factors SRF and MYOCD was decreased. The expression of Ki67, PCNA and BAX was increased, and the expression of Bcl-2 was decreased. The phenotype of corpus spongiosum VSMCs in hypospadias changed from the contractional type to the synthetic type. This phenotypic modulation was associated with increased proliferation and apoptosis rates. SRF and MYOCD may be the main factors mediating the phenotypic modulation of urethral corpus spongiosum VSMCs.

Topographic Labeling of Glans Penis and Corpus Spongiosum When Planning Surgery for Distal Hypospadias

Background

Outcomes of hypospadias surgery continually lagged behind anticipations among practitioners, prompting continuing refinement of approaches. Refinements typically involved modified surgical techniques.

Objective

Herein, the author aimed for reporting the comparative anatomical topography of distal hypospadias anomaly vs normal controls, to boost its reparative approach.

Patients and Methods

This is a prospective clinical study of distal hypospadias cases presented to the author’s facility between June 2018 and June 2020. Anatomical topography of the hypospadias penis was studied concerning the corresponding marks in another control cohort with normal penile development. Meatal marks, glans wings alignment, frenulum, and corpus spongiosum were the anatomical landmarks looked into. Operative correction of the anomaly was carried out considering these landmarks, aiming for pinpoint reassembly. The control group served to identify the normal topography.

Results

The author studied 49 cases of distal hypospadias and 10 uncircumcised boys with an otherwise normal penile anatomy. In distal hypospadias, the corpus spongiosum splayed out – at about mid-penile level – ending at a consequently splayed glans penis, rather than involving a primary glans defect. After the corpus spongiosum had been closed/zippered up, no further glans wings’ surgical dissection was deemed necessary to attain the anatomical topography identified by the control group. By the end of a median follow-up period of 14 months, no urethrocutaneous fistulae or meatal stenoses were reported, with a typical apical re-assembled meatus, glans ventrum, and frenulum.

Conclusion

Topographic mapping against control subjects revealed that the glans penis is fully developed in boys with distal hypospadias. After the spongiosal plate has been adequately zippered up, no glans wings’ surgical dissection was deemed necessary to attain the typical glanular topography identified by the control group.

Using Buck's Fascia as an Integral Covering in Urethroplasty to Restore the Anatomical Structure of the Penis in One-Stage Hypospadias Repair: A Multicenter Chinese Study Comprising 1,386 Surgeries

Objectives: The objective of the study is to investigate the feasibility and efficacy of urethroplasty with a Buck's fascia integral-covering technique (BFIC) to wrap and restore the normal anatomical structure of the penis in one-stage hypospadias surgery. Methods: One-stage surgeries for hypospadias management were performed using BFIC from January 2016 to September 2020 at four high-volume medical centers in China. The technique integrates Buck's fascia with glans wings to mobilize and wrap the urethra and restore penile anatomical relationships. The clinical data, postoperative follow-up data, and complications were recorded, and the results were analyzed. Results: A total of 1,386 patients were included in the study: 1,260 cases of primary hypospadias and 126 cases of re-operations; distal in 382 cases (27.6%), mid-shaft in 639 (46.1%), proximal in 365 (26.3%); tubularized incised plate (TIP) in 748 cases, inlay-graft in 124, onlay-graft in 49, Mathieu in 28, free-tube graft urethroplasty in 406, and 31 of hybrid procedures. One thousand one hundred forty-two patients (82.4%) were found to have penile curvature (>10°) after artificial erection and all corrected by dorsal plication/s or transection of the urethra plate (UP) simultaneously. The median followed-up time was 27 months (6-62). A total of 143 (10.3%) complications were recorded: 114 (9.0%) in the primary operations and 29 (23%) in the re-operations, 15 (3.9%) in distal hypospadias, 61 (9.5%) in mid-shaft, and 67 (18.4%) in proximal. The complication rate in UP preservation and transection was 10.1 and 10.8%, respectively. Of all case complications, there were 73 (5.2%) of fistula, 10 (0.6%) of dehiscence, 22 (1.6%) of meatal stenosis, 21 (1.5%) of stricture, 6 (0.7%) of diverticulum, and resident curvature in 11 cases (1.2%). The overall complication rate in TIP and free-tube procedure was 9.8 and 9.9%, respectively, and fistula occurred in primary TIP of 33 cases (4.9%). Conclusions: Buck's fascia with the glans can be used as an integral covering technique in one-stage distal to proximal hypospadias and primary or re-operative hypospadias repair. It is safe, feasible, and effective for the repair of hypospadias.

Assessing the potential regeneration ability of corpus spongiosum in rabbit models

Most congenital or acquired urethral diseases are usually accompanied by corpus spongiosum (CS) defects. However, Substitution urethroplasty can only reconstruct urethral lumen, not the CS. Many long-term complications occur due to the lack of protection from CS. Is CS a kind of tissue that cannot be repaired by regeneration and self-healing? In this study, the CS defect with urethral mucosa intact model was established in rabbits by removing the ventral CS tissue. Based on this model, three groups of different CS defect sizes, with lengths of 0.5 cm (Group A), 1.0 cm (Group B) and 1.5 cm (Group C), were then constructed, respectively, to assess the potential regeneration ability of CS. Three months later, the entire urethra, including the CS defect, was assessed by histological staining. Results showed that the vascular sinusoids were completely removed from urethral mucosa. The rabbit model of CS defect was established successfully. Three months post-operatively, the CS defects in all the 3 groups were replaced by disordered collagen instead of regenerating typical sinusoid-like vascular structure, which is significantly different from the normal CS rich in vascular sinusoids. The CS defects could not be repaired through self-healing. The potential regeneration ability of CS is extremely poor.