Study on Protein Nanomarker Combined with Vascular Endothelial Growth Factor to Improve Vascularization of Rabbit Urethral Defect Tissue Engineering

To construct the tissue engineering urethral material that is closest to the normal urethral structure in the true sense in vitro. Abdominal ADSC from a 2-month-old New Zealand white rabbit was extracted and directly compounded with non-woven polyglycolic acid (PGA) (control group) to induce the differentiation of myoblasts and epithelial-like cells in vitro and shaped into urethral structure lumen Observation group); After Gd chelating protein nano-labeling and VEGF-loaded sustained release, the rabbit model of a long urethral defect was replanted and cultured for 4 weeks, 8 weeks and 12 weeks, respectively. There was no difference in urinary tract patency rate, urinary tract infection, and renal dysfunction rate between the two groups (P > 0.05). The urine flow rate in the observation group was significantly higher than that in the control group, and the residual volume decreased (P < 0.05). The blood vessel density and CD31 percentage in the observation group increased (P < 0.05). Compared with the conventional ADSC directly in contact with the composite material to construct the urethra, in vitro induction of ADSC to myoblasts and epithelial-like cells respectively, and then use the cell membrane technology to build a tissue engineering urethral material that is closest to the normal urethral structure in the true sense, and loaded with VEGF Loop release technology can significantly improve urodynamic functions, optimize tissue engineering urethral structure and vascularization, and is expected to become a new technology for constructing new tissue engineering urethral materials.

Predictive Value of C-Reactive Protein for Early Postoperative Complications in Children After Hypospadias Surgery

Background: This study explored the predictive value of postoperative C-reactive protein in children with hypospadias for postoperative complications and the risk factors.Methods: The clinical and follow-up data of 106 children with hypospadias who were treated with operations at Kunming Children's Hospital in 2020 were, respectively, analyzed. According to the occurrence of postoperative complications, the patients were divided into two groups: 25 patients with postoperative complications were the complications group, and 81 without postoperative complications were the control group. The baseline data, clinical characteristics, laboratory test indexes, and outcome of the two groups were collected. Receiver operating characteristic (ROC) was used to calculate the optimal cutoff value of C-reaction protein (CRP). Logistic regression was used to analyze the risk factors of hypospadias after surgery. A probability value (P) &lt; 0.05 was considered statistically significant.Results: According to the result of the ROC curve, the optimal cutoff value of CRP was 11.7 mg/L. Logistic regression showed that the length of urethral defect, the urethral material, the operative produce, and the postoperative CRP level were related to the occurrence of postoperative complications of patients with DCC. The length of the urethral defect and the CRP level were the independent risk factors of the prognosis of hypospadias patients. The CRP level was related to the occurrence of postoperative complications and fistula.Conclusions: Postoperative CRP level can be used as a reliable marker for predicting the prognosis of hypospadias patients.

Creation of Tissue-Engineered Urethras for Large Urethral Defect Repair in a Rabbit Experimental Model

Introduction: Tissue engineering is a potential source of urethral substitutes to treat severe urethral defects. Our aim was to create tissue-engineered urethras by harvesting autologous cells obtained by bladder washes and then using these cells to create a neourethra in a chronic large urethral defect in a rabbit model.Methods: A large urethral defect was first created in male New Zealand rabbits by resecting an elliptic defect (70 mm2) in the ventral penile urethra and then letting it settle down as a chronic defect for 5–6 weeks. Urothelial cells were harvested noninvasively by washing the bladder with saline and isolating urothelial cells. Neourethras were created by seeding urothelial cells on a commercially available decellularized intestinal submucosa matrix (Biodesign® Cook-Biotech®). Twenty-two rabbits were divided into three groups. Group-A (n = 2) is a control group (urethral defect unrepaired). Group-B (n = 10) and group-C (n = 10) underwent on-lay urethroplasty, with unseeded matrix (group-B) and urothelial cell-seeded matrix (group-C). Macroscopic appearance, radiology, and histology were assessed.Results: The chronic large urethral defect model was successfully created. Stratified urothelial cultures attached to the matrix were obtained. All group-A rabbits kept the urethral defect size unchanged (70 ± 2.5 mm2). All group-B rabbits presented urethroplasty dehiscence, with a median defect of 61 mm2 (range 34–70). In group-C, five presented complete correction and five almost total correction with fistula, with a median defect of 0.3 mm2 (range 0–12.5), demonstrating a significant better result (p = 7.85 × 10−5). Urethrography showed more fistulas in group-B (10/10, versus 5/10 in group-C) (p = 0.04). No strictures were found in any of the groups. Group-B histology identified the absence of ventral urethra in unrepaired areas, with squamous cell metaplasia in the edges toward the defect. In group-C repaired areas, ventral multilayer urothelium was identified with cells staining for urothelial cell marker cytokeratin-7.Conclusions: The importance of this study is that we used a chronic large urethral defect animal model and clearly found that cell-seeded transplants were superior to nonseeded. In addition, bladder washing was a feasible method for harvesting viable autologous cells in a noninvasive way. There is a place for considering tissue-engineered transplants in the surgical armamentarium for treating complex urethral defects and hypospadias cases.

Cell-Seeded Acellular Artery for Reconstruction of Long Urethral Defects in a Canine Model

The management of urethral stricture remains a major therapeutic challenge in clinics. Herein, we explored the feasibility of reconstructing a relatively long segment of the urethra by the cell-seeded acellular artery in a canine model. The acellular arterial matrix was obtained from the excised carotid artery of donor dogs. Autologous adipose-derived stem cells (ADSCs) from 6 male dogs were grown and seeded onto the premade acellular arterial matrix. A 3 cm long segment of the urethra was resected in 12 male dogs. Urethroplasty was performed with the acellular arterial matrix seeded with ADSCs in 6 animals and without cells in 6. Serial urethrography was performed at 1 and 3 months postoperatively. Wide urethral calibers without any signs of strictures were confirmed in all 6 animals in the experimental group. In contrast, urethral stricture was demonstrated in 3 animals in the control group. The graft was highly epithelialized and smooth in the experimental group, while graft contracture and scar formation were showed in the control group. Histologic analysis of the cell-seeded arterial matrix at 1 month confirmed the presence of multilayered urothelium and muscle. The levels of tissue formation developed over time with a progressive increase in muscle content. In contrast, extensive fibrosis and sparse smooth muscle were seen in animals treated with matrix without ADSCs. This study provides preclinical evidence that the ADSC-seeded arterial matrix can be used as a tubularized scaffold in the reconstruction of 3 cm long urethral defect in a male canine model. The ADSC-seeded arterial matrix remodels and regenerates normal-appearing urethral tissue layers over time.

Partial Inferior Pubectomy in the Delayed Repair of Pelvic Fracture Urethral Injury: Adopting a Bone-nibbling Technique

Background: The use of wedge inferior pubectomy can be challenging to many urethral surgeons. Our objective was to introduce a bone-nibbling technique to accomplish a partial inferior pubectomy (PIP) in a resource-poor setting, and to report the medium- to longterm outcome of using the technique. Methods: Five patients were recruited (mean age: 38.8 years) who presented, over a 30-month period, with posterior urethral fibrosis from a pelvic fracture urethral injury (PFUI). One had failed a previous attempt at posterior urethral reconstruction elsewhere. The length of urethral defect was from 2 to 4 cm. We describe a bone-nibbling technique used to carry out PIP for the delayed repair of PFUI in these patients. The outcomes in the medium to long term of surgical procedures done with this technique are presented. Results: Immediate postoperative complications in all were essentially a Clavien–Dindo grade I. Peak flow rate assessed 12 weeks’ post operation was between 20 mL/s and 23 mL/s (mean: 21 mL/s). The longest duration of follow-up was 34 months, and all patients were voiding satisfactorily. Conclusions: A satisfactory and durable outcome can be obtained from nibbling at the bone from the inferior margin of the pubic bone to achieve PIP. This is of interest to lower urinary tract reconstructive surgeons who have concerns with chiseling-out wedge of the inferior pubis. Keywords: Bone nibbling, Partial inferior pubectomy, PFUI, Posterior urethra, Urethral anastomosis

Tubularized urethral reconstruction using everted saphenous vein graft in a beagle model

Background A long segment stricture in the anterior urethra is a challenge in urology. We conducted a study to investigate the efficacy of anterior urethral reconstruction using an everted saphenous vein graft (SVG) in a tubular fashion. Methods Twelve male beagles were randomly divided into three groups: experimental group (n = 5), control group (n = 5) and normal group (n = 2). A 3 cm defect in the anterior urethra was created. Autologous SVG was harvested. In the experimental group, urethral defect was replaced by an everted SVG in a tubular fashion. In the control group, urethral reconstruction was performed using an uneverted SVG. Beagles in all groups received retrograde urethrography to evaluate urethral patency and were killed for histological examination 6 months after operation. Results Four beagles in the experimental group had no voiding difficulty and the other one could not void spontaneously. Retrograde urethrography showed the four beagles in experimental group had wide urethral lumens. Ether urethral stricture or fistula were detected in all animals in the control group. Histological analysis of the four beagles in the experimental group indicated the everted SVG completely integrated into the urethra. The reconstructed urethra contained a wide lumen and was completely covered by urothelium. The periurethral collagen and muscle fibers formed and were highly organized. Everted SVG showed a high ability of neovascularization. In the control group, the reconstructed segment showed a fibrotic urethral lumen where the urothelium was not intact. Only few new capillaries were formed. Conclusions Everted SVG demonstrates for a promising strategy for potential urethral stricture repair.

Self-inflicted gunshot injury to the external genitalia: a case report and review of literature

Background Gunshot wounds of the external genitalia are rare. Rarer still are civilian self-inflicted gunshot wounds of the external genitalia. The protocol for the management of gunshot wounds of the penis especially with respect to urethral injuries is not fully established. Case presentation We present a 27-year-old male undergraduate student, who accidentally shot himself in the penis. He sustained American Association for the Surgery of Trauma (AAST) grades IV to V injuries to the penis, scrotum and left testes. He was managed in a multistage, multi-disciplinary fashion including staged buccal mucosal graft repair of 4 cm proximal penile urethral defect with satisfactory cosmetic and functional outcome. Conclusions Excellent functional and cosmetic results may be obtained after severe penetrating trauma to the external genitalia even in low resource centres in the hands of non-reconstructive urologists. Buccal mucosal graft is a viable option for two stage reconstruction of the urethra.

Tubularized Urethral Reconstruction Using Everted Saphenous Vein Graft in A Beagle Model

Background: The repair of anterior urethral stricture and hypospadias require urethral reconstruction. We conduct the study to investigate the efficacy of anterior urethral reconstruction using everted saphenous vein graft in tubular fashion. Methods: Twelve male beagles were randomly divided into three groups: experimental group( n=5), control group( n=5) and normal group( n=2). A 3 cm defect in anterior urethra was created. Autologous saphenous vein graft was harvested. In experimental group, urethral defect was replaced by everted saphenous vein graft in tubular fashion. In control group, urethral reconstruction was performed using uneverted saphenous vein graft. At 6 months postoperatively, beagles in all groups received retrograde urethrography to evaluate urethral patency and were killed for histological examination. Results: Retrograde urethrography showed the urethral caliber of beagles in experimental group were similar to those of normal. Ether urethral stricture or fistula were detected in all animals in control group. In experimental group, the everted saphenous vein graft completely integrated into the urethra. The reconstructed urethra had a wide lumen and was completely covered by urothelium. The subepithelial collagen and muscle fibers were well formed and highly organized. Everted saphenous vein graft had a high ability of neovascularization. In control group, the reconstructed segment had a fibrotic urethral lumen in which urothelium was not intact. And there were few newly formed capillaries. Conclusions: Everted saphenous vein graft can be used as tubular substitute material for anterior urethral strictures and hypospadias.

Single-stage urethroplasty: An eight-year single-centre experience and its associated factors for urethrocutaneous fistula

Introduction: This study aimed to describe single-stage urethroplasty and to determine factors associated with urethrocutaneous fistula after the procedure at our institution. Methods: All hypospadias patients without any prior surgery who underwent single-stage urethroplasty from July 2010 to January 2018 were included. In total, 179 patients were followed for at least one year postoperatively. Information on types of hypospadias, operation techniques, chordee degree, preoperative pyuria (urine white blood cell count >5/HPF), urethral defect length and urethrocutaneous fistula formation was collected. Results: We obtained 103 cases of posterior (57.5%), middle (57 cases) and anterior (19 cases) hypospadias on whom onlay preputial island flap (71 cases), tubularized incised plate (46 cases) and Duckett’s transverse preputial island flap (35 cases) were conducted. After 47.1±25.8 months of follow-up, urethrocutaneous fistula were found in 23 (12.8%) patients associated with posterior hypospadias occurrence ( p=0.025), longer urethral defect ( p=0.007) and preoperative pyuria ( p<0.001). Chordee degree ( p=0.886) and age ( p=0.187) were not significant factors associated with urethrocutaneous fistula formation. Conclusion: Single-stage urethroplasty is a versatile procedure for various hypospadias cases, with a urethrocutaneous fistula rate of 12.8%. Posterior hypospadias, preoperative pyuria and longer urethral defect were associated with urethrocutaneous fistula formation. Level of evidence Level 2B.

Reconstruction of a Wide Defect in the Prostatic Urethra after Abdomino-Perineal Amputation Using Buccal Mucosa Free Graft and Pedicled Gracilis Muscle Flap

Lesions with significant substance loss in the prostatic segment of the urethra can represent a reconstructive challenge, especially when peripheral tissues are damaged or poor-vascularized. We present an infrequent clinical case in which a prostatic urethral defect of 2.6cm in length following abdomino-perineal amputation was repaired using a free buccal mucosa graft which was stabilized with a muscular gracilis flap. Complementing the buccal mucosa graft with a well-vascularised support the stability of the graft could be enhanced and the rates of fistula or strictures reduced.