STATEMENT OF SIGNIFICANCE: In this study we have tissue engineered a novel cell free tubular collagen based scaffold and used it as a urethral graft in a rabbit model. The novelty of our technique is that the tube can be sutured. Testing showed better burst pressures and the grafts could then be successfully implanted after a urethral excision. This long term study demonstrated excellent biocompatibility of the 2cm graft and gradual regeneration with time, challenging the current literature. Finally, the main impact is that we describe an off-the-shelf and cost-effective product with comparable surgical outcome to the cellular grafts.
OBJECTIVE: To investigate what type of flap used during Snodgrass or fistula repair reduces the incidence of fistula occurrence.
EVIDENCE ACQUISITION: We systematically reviewed published results for urethral covering during Snodgrass and fistula repair procedures. An initial online search detected 1740 reports. After exclusion of ineligible studies at two stages, we included all patients with clear data on the covering technique used (dartos fascia [DF] vs tunica vaginalis flap [TVF]) and the incidence of postoperative fistula.
EVIDENCE SYNTHESIS: A total of 51 reports were identified involving 4550 patients, including 33 series on DF use, 11 series on TVF use, and seven retrospective comparative studies. For distal hypospadias, double-layer DF had the lowest rate of fistula incidence when compared to single-layer DF (5/855 [0.6%] vs 156/3077 [5.1%]; p=0.004) and TVF (5/244, 2.0%), while the incidence was highest for single-layer DF among proximal hypospadias cases (9/102, 8.8%). Among repeat cases, fistula incidence was significantly lower for TVF (3/47, 6.4%) than for DF (26/140, 18.6%; p=0.020). Among patients with fistula after primary repair, the incidence of recurrence was 12.2% (11/90) after DF and 5.1% (5/97) after TVF (p=0.39). The absence of a minimum follow-up time and the lack of information regarding skin complications and rates of urethral stricture are limitations of this study.
CONCLUSION: A double DF during tubularized incised plate urethroplasty should be considered for all patients with distal hypospadias. In proximal, repeat, and fistula repair cases, TVF should be the first choice. On the basis of these findings, we propose an evidence-based algorithm for surgeons who are still in their learning phase or want to improve their results.
PATIENT SUMMARY: We systematically reviewed the impact of urethral covering in reducing fistula formation after hypospadias repair. We propose an algorithm that might help to maximize success rates for tubularized incised plate urethroplasty.
MATERIAL AND METHODS: Over a period of eight years, from January 1997 to December 2004, 126 hypospadias patients were treated, 90 of these patients received two-stage repairs and 36 patients received single-stage repairs. HOSE questionnaire and uroflowmetry data were obtained to evaluate the long-term outcome of the two-stage hypospadias repairs.
RESULTS: The age at the time of assessment ranged from 8 to 23 years-old, with a mean follow-up time of 39.78 months. Thirty-five patients had proximal hypospadias, and 20 had distal hypospadias. Of the 55 patients who received complete two-stage hypospadias repair and agreed to participate in the study, nineteen patients had acceptable HOSE scores and 36 patients had non-acceptable scores. The uroflow rates of 43 of the subjects were below the fifth percentile in three patients, equivocal (between the 5(th) and 25(th) percentile) in four patients and above the 25(th) percentile in 36 patients.
CONCLUSION: Two-stage repair is a suitable technique for all types of hypospadias with varying outcomes. HOSE and uroflowmetry are simple, easy, non-invasive and non-expensive tools for objectively assessing the long-term outcomes of hypospadias repair.
METHODs: Data collection was based on the key articles published in English language in years between 2006 and 2018 using the searching terms of urethral stricture and tissue engineering on PubMed database.
RESULTS: Differentiation of mesenchymal stem cells into urothelial and smooth muscle cells to be used for urologic application does not offer any advantage over autologous urothelial and smooth muscle cells. Among studied scaffolds, synthetic scaffolds with proper porosity and mechanical strength is the best option to be used for urethral tissue engineering.
CONCLUSION: Hypoxia-preconditioned mesenchymal stem cells in combination with autologous cells seeded on a pre-vascularized synthetic and biodegradable scaffold can be said to be the best combinatory strategy in engineering of human urethra.
MATERIALS AND METHODS: A systematic online search was conducted according to PRISMA statement for publications reporting on UR after RC. From initial 802 results, 14 articles including 6169 patients were included finally after exclusion of ineligible studies.
RESULTS: The incidence rate of UR was 4.4% (1.3%-13.7%). It was significantly lower with neobladder diversion (odds ratio = 0.44, 95% CI: 0.24-0.79, P = 0.006). Muscle invasion (hazard ratio = 1.18, 95% CI: 0.86-1.62, P = 0.31), carcinoma in situ (hazard ratio 0.97, 95% CI: 0.64-1.47, P = 0.88), prostatic stromal involvement (hazard ratio = 2.26, 95% CI: 0.01-627.75, P = 0.78), and prostatic urethral involvement (hazard ratio = 2.04, 95% CI: 0.20-20.80, P = 0.55) have no significant effect on UR. Men displayed tendency toward higher incidence of UR (odds ratio = 2.21, 95% CI: 0.96-5.06, P = 0.06). Absence of recurrence displayed tendency toward better disease specific survival, yet not significant (hazard ratio = 0.84, 95% CI: 0.66-1.08, P = 0.17). These results are limited by the retrospective nature of the included studies.
CONCLUSION: Muscle invasion, carcinoma in situ and prostatic stromal or urethral involvement at time of RC have no significant effect on UR. Orthotopic neobladder is associated with a significant lower risk of UR after RC.