A Critical Analysis of Stented and Unstented Tubularized Incised Plate Urethroplasty Through a Prospective Randomized Study and Assessment of Factors Influencing the Functional and Cosmetic Outcomes

Do the materials matter? A review of the literature and analysis of the materials properties of urethral stents for hypospadias repair

INTRODUCTION

Despite the prevalence of hypospadias surgery and the common use of postoperative urethral stents, there has been no evaluation of the material properties of common stents. Our study sets out to close this gap with a literature review of recent publications comparing outcomes after hypospadias surgery for different urethral stent types and an evaluation of the material properties of four common urethral stents.

STUDY DESIGN

A review of the English language literature from 2011 to 2021 was performed. Thermal analysis and mechanical analysis of the Zaontz Urethral Stent, the Firlit-Kluge Urethral Stent, the Koyle Diaper Stent, and the Bard Premature Infant Feeding Tube was also undertaken.

RESULTS

Out of 165 papers, four met inclusion criteria. There was limited research on this topic, and no significant evidence that different stent materials impacted surgical complication rates. One study found improved comfort with the Zaontz stent, and another found a reduction emergency room visits with the Koyle stent. Using a foley balloon was associated with increased fistula rates, though this was likely due to the balloon design and not the material. Analysis of stents shows that all four are rubbery polymers at body temperature (Summary Table). The Zaontz and Koyle stents are thermoplastic elastomers with strong melting transitions above body temperature, but the Firlit-Kluge stent is amorphous at 37 °C and is likely covalently cross-linked to generate the network. The Bard feeding tube was the stiffest, with a Young's Modulus of 14.0 ± 0.78 (compared to 4.12 ± 0.56 for Zaontz, 4.92 ± 0.63 for Firlit-Kluge, and 4.09 ± 0.49 for Koyle). The Bard Feeding Tube is also the least extensible, fracturing at just over 300% strain compared to the other stents that can be stretched to greater than 2000% strain before fracture. Cyclic deformation studies demonstrate that the Zaontz, Firlit-Kluge, and Koyle stents are able to stretch and recover their shape more completely, a finding determined by the lower amount of plastic deformation those stents display compared to the Bard Feeding Tube.

DISCUSSION

While there is little information associating urethral stent type with outcomes after hypospadias surgery, material properties may account for findings of prior studies. Stiffer stents may contribute to decreased postoperative comfort, while a stent that is too soft and extensible may have issues with dislodgement, kinking and breaking.

CONCLUSION

This study provides the foundation for future work optimizing urethral stents, designing support for regenerative medicine applications, and improving hypospadias outcomes.

Long-term outcome of non-stented tubularized incised plate urethroplasty for distal hypospadias repair: a complication analysis

Introduction

Although it is apparently simpler to perform unstented tubularized incised plate (TIP) repair for distal hypospadias repair, consensus on feasibility of the use of unstented repair is still a matter of debate. Evidence reporting that unstented repair outcome is comparable to stented repair, especially in the long-term, is still weak due to reporting outcome inconsistencies, different study designs, inclusion of more than one technique, and inherent variability in meatal locations. Thus, we need a continuous and evolving assessment of the outcome of unstented repair to compile adequate evidence on the advantage of unstented TIP repair in distal hypospadias entity. The aim of this article was to review our long-term results with tubularized incised plate urethroplasty for distal hypospadias repair without a postoperative stent to determine its outcome which might justify its use.

Material and methods

After a review of 154 patients with distal penile hypospadias, who underwent repair in Minia Urology & Nephrology University Hospital in the period between June 2015 and February 2018, we excluded cases who underwent MAGPI repair, redo cases and patients who failed to complete follow-up. We chose 72 patients who had only 1^st time TIP repair and whom we could contact. A total of 44 out of 72 cases with stented repair were assigned to Group A, while 28 cases with unstented repair were assigned to Group B. Success was assessed based on Hypospadias Objective Penile Evaluation (HOPE) score by three separate senior pediatric urology consultants, independent of the surgeon and in the absence of high post-void residual urine (PVR). Average rate was calculated to be compared between both study groups.

Results

There was no statistically significant difference regarding preoperative meatal location and age at repair and short-term complications. In the long-term; there was no statistically significant difference between the occurrence of urethrocutanous fistula (UCF, 4 vs 2 cases in Group A & B, respectively) and complete disruption (2 cases in each group) with need for redo repair. Results of total mean of HOPE score calculated showed no statistically significant differences between study groups and also failed to showed statistical significance on individual domains of HOPE score.

Conclusions

Unstented TIP repair showed a similar outcome to stented TIP repair of distal hypospadias especially in the long-term despite a more troublesome early postoperative period.

Hypospadias in toddlers: a multivariable study of prognostic factors in distal to mid-shaft hypospadias and review of literature

Background

Tubularized incised plate urethroplasty is the most common hypospadias repair technique. However, there are unanswered questions and debates about the anatomical prognostic factors affecting the repair outcomes. This study tried to address some of the problems in the studies compromising the results of the current body of literature.

Methods

A prospective cohort of 101 males aged 1–3 years undergoing primary distal to mid-shaft hypospadias repair were enrolled in the study. Complications including edema, erection, inadvertent removal of the urethral stent, surgical wound infection, bladder spasm, hematoma, and hemorrhage were evaluated. Studies in the current literature were reviewed to achieve a better perspective for future investigations.

Results

Persistent complications were found in 16 cases (15.8%) including fistula formation, the persistence of chordee, meatal stenosis, glans, and urethral dehiscence. The mean follow-up time was 6.6±3.4 months. In the single-variable analysis, the meatal location, the length and width of the urethral plate, and the reversible acute postoperative events were significantly associated with the complications. Furthermore, fistula formation was associated with acute surgical site infection (p<0.001). However, the multivariable regression study revealed the presurgical meatal location to be the only statistically significant factor (p=0.03). Notably, the glans diameter or glanular groove shape, urethral plate dimensions, or presence of mild chordee were not independently associated with the outcomes (p>0.05).

Conclusions

Our study on the toddlers with hypospadias surgery revealed that the location of urethral meatal was the main predicting factor in the development of major complications. Furthermore, the fistula formation at the infected surgical site emphasizes the importance of postsurgical care.

What are the factors affecting glanular dehiscence after hypospadias surgery?

BACKGROUND

Glanular dehiscence (GD) is one of the main complications after hypospadias surgery. There is a limited number of publications regarding GD in the literature.

OBJECTIVE

The aim of this work is to reveal the factors that affect GD after a literature review.

EVIDENCE ACQUISITION

A literature search for relevant articles was performed in database using the search term glans dehiscence without setting date range limit or any other limits. All articles related to GD after hypospadias surgery were included in this study. After collecting the information from full text articles, 71 articles were included in this systematic review. In these studies, localization of hypospadic meatus, type of surgery, and other clinical data which were thought to behave as risk factors for GD were obtained. Chi-Square test was used to evaluate the differences between the parameters, where p < 0.05 was taken as statistically significant.

RESULTS

After evaluating the 71 articles that met the inclusion criteria, 309 cases (3.48%) of GD after 8858 hypospadias repairs were obtained in this review. GD rates were found significantly high for proximal hypospadias (5%), two-stage hypospadia repairs (5%) and re-do hypospadias repair (8.75%) (p = 0.002, 0.022, and 0.004, respectively). Glans width <14 mm, urethral plate (UP) width <7 mm, hypospadias surgeries performed before 6 months of age and after puberty, and caudal block anesthesia increased the rate of GD.

CONCLUSIONS

The rate of GD increases after proximal, cripple and staged hypospadias surgeries, a glans width <15 mm and UP width <8 mm, postpubertal surgeries, and caudal anesthesia use during surgery.

Medium-term outcome after stented and un-stented distal urethroplasty: A retrospective analysis on redo-urethroplasty need and cosmetic results

INTRODUCTION

Long-term complication rates after distal hypospadias repair can be close to 20%. There are no available guidelines regarding the need for a catheter in distal urethroplasty. We report a retrospective analysis on medium-term redo-urethroplasty rate and cosmetic results after a two-years pilot study on stented/un-stented distal urethroplasties.

MATERIALS AND METHODS

A total of 11 stented (Group A) and 17 un-stented (Group B) Snodgrass-procedures were performed by the same pediatric surgeon at our Institution (2011-2013). The median age at surgery was 2.1 years (range 1-8.5). Inclusion criteria were primitive distal defect, same surgeon in both interventions, catheter-free discharge. The median follow-up was 6.4 years (range 1.5-8.1). All patients received at least one post-operative clinical-cosmetic examination (HOSE). The aim of our study was to compare medium-term complications and redo-urethroplasty rates before starting a randomized study. A retrospective analysis was performed. We used Fisher's exact-test (P < 0.05) for statistical analysis.

RESULTS

Of 28 complications, 5 required redo-surgery: 2/11 stented-cases, 3/17 un-stented. Cosmetic results were satisfactory in both groups. These results were not statistically significant (P = 1.000).

CONCLUSION

Long-term follow-up is mandatory to know redo-urethroplasty rate and cosmetic outcome after distal stented/un-stented repair. Further studies are needed to evaluate the role of catheter placement and the definitive outcome in distal urethroplasty.

Medium-term outcome after stented and un-stented distal urethroplasty: A retrospective analysis on redo-urethroplasty need and cosmetic results

INTRODUCTION

Long-term complication rates after distal hypospadias repair can be close to 20%. There are no available guidelines regarding the need of a catheter in distal urethroplasty. We report a retrospective analysis on medium-term redo-urethroplasty rate and cosmetic results after a two-year pilot study on stented/un-stented distal urethroplasties.

MATERIALS AND METHODS

A total of 11 stented (Group A) and 17 un-stented (Group B) Snodgrass-procedures were performed by one pediatric surgeon at our Institution (2011-2013). The median age at surgery was 2.1 years (range 1-8.5). Inclusion criteria were primitive distal defect, same surgeon in both interventions, catheter-free discharge. The median follow-up was 6.4 years (range 1.5-8.1). All patients received at least one post-operative clinical-cosmetic examination (HOSE). The aim of our study was to compare medium-term complications and redo-urethroplasty rates before starting a randomized study. A retrospective analysis was performed. We used Fisher's exact-test (P<0.05) for statistical analysis.

RESULTS

Of 28 complications, 5 required redo-surgery: 2/11 stented-cases, 3/17 un-stented. Cosmetic results were satisfactory in both groups. These results were not statistically significant (P=1.000).

CONCLUSION

Long-term follow-up is mandatory to know redo-urethroplasty rate and cosmetic outcome after distal stented/un-stented repair. Further studies are needed to evaluate the role of catheter placement and the definitive outcome in distal urethroplasty.

Nonstented Tubularized Incised Plate Distal Hypospadias Repair: A Single Center 5 Years' Experience

OBJECTIVES

To report our immediate and delayed outcomes of nonstented tubularized incised plate (TIP) distal hypospadias repair.

METHODS

We retrospectively reviewed all charts of children who underwent distal hypospadias repair in a single children's hospital from 2013 to 2018. Patients' demographics, hypospadias characteristics, operative technique, and immediate and delayed outcomes were recorded.

RESULTS

Of 280 consecutive distal hypospadias repairs that were identified, 74 were excluded due to the use of a repair other than TIP. Eleven stented TIP repairs were excluded as well. Of 195 nonstented repairs, immediate postoperative voiding complications were recorded in 11 (5.6%) and included multiple/split stream in 6 (3%), dysuria and voiding difficulty in 2 (1%), urinary retention in 2 (1%), and gross hematuria that spontaneously resolved in 1 (0.5%). Late follow up was recorded in 142 of 195 (72.8%) repairs. Delayed urethroplasty/glansplasty complications were recorded in 12 (8.5%) and included urethrocutaneous fistula in 10 (7.0%), meatal stenosis in 6 (4.2%) and glans/urethroplasty dehiscence in 2 (1.4%).

CONCLUSION

Avoiding postoperative urethral stents in distal hypospadias TIP repair reduces the morbidity associated with the stent and is a feasible option that carries acceptable immediate and delayed complication rates. Avoiding the stent eliminates stent-related bladder spasms, the need for other medications, and the short-term office visit for stent removal, therefore reducing parental anxiety, patient discomfort, and reducing cost.

Complications Following Primary Repair of Non-proximal Hypospadias in Children: A Systematic Review and Meta-Analysis

Purpose: The aim of this study was to systematically review the literature on the complications and postoperative outcomes of children with non-proximal hypospadias. Methods: Electronic databases including PubMed, Embase, and Cochrane Library CENTRAL were searched systematically from January 1990 to June 2020 for the literature that reported the postoperative outcomes of patients with non-proximal hypospadias. Non-proximal hypospadias encompassed distal and mid-penile hypospadias. Results: We included 44 studies involving 10,666 subjects. Urethrocutaneous fistula (UCF) was the most common complication with an incidence of 4.0% (95% CI, 3.1-5.0%). Incidence of overall complications was 8.0% (95% CI, 6.3-9.8%). Meta-regression analysis revealed that length of urethral stent indwelling (coefficient 0.006; 95% CI, 0.000-0.011; p = 0.036) and penile dressing (coefficient 0.010; 95% CI, 0.000-0.021; p = 0.048) were two risk factors for UCF. Multivariate meta-regression analysis did not identify any independent risk factors for UCF. No differences were found between stent and stentless groups in non-proximal hypospadias regarding incidences of UCF (OR, 0.589; 95% CI, 0.267-1.297), meatal stenosis (OR, 0.880; 95% CI, 0.318-2.437), and overall complications (OR, 0.695; 95% CI, 0.403-1.199). No differences were found between foreskin preservation and circumcision in terms of complications either. Conclusions: UCF is the most common complication following hypospadias repair with an incidence of 4.0%. Independent risk factors for UCF were not identified in the current research. Distal hypospadias repair without stent indwelling is not likely to compromise the postoperative outcome. Further studies should be designed to explore the differences between different surgical approaches and the potential risk factors for complications following hypospadias repair.

Stented versus Non-Stented Snodgrass Urethroplasty for Distal Hypospadia Repair

BACKGROUND

Hypospadia is one of the most common congenital anomalies in children. Patients with distal hypospadias can be treated successfully with a tubularized incised plate (TIP) urethroplasty, usually with a postoperative urethral stent to divert urine into the diaper or a urine bag for approximately 1 week. However, these stents have their own morbidity and complications. We therefore tried to determine the safety of distal penile hypospadias repair without the use of a postoperative stent.

PATIENTS AND METHOD

Fifty patients with distal penile hypospadias were prospectively assessed from May 2016 to August 2018. All patients underwent Snodgrass urethroplasty by the same surgeon. Half of the patients had a postoperative stent for 1 week. The other half had no stent. Clinical follow-up was over 6 months with an emphasis on possible stent-related complications.

RESULTS

Fifty children underwent TIP urethroplasty for distal hypospadia repair. The mean age was 5.9 years (range 2-12). In 25 cases, a stent was removed within 1 week. In the other 25 cases, no postoperative stent was placed. The overall complication rate for the stented group was 48% (n = 12) and for the non-stented group 68% (n = 17), respectively. In the stented group, 1 patient (4%) developed a fistula, whilst there were 2 (8%) in the non-stented group. All fistulas were repaired after 6 months postoperatively. Neourethral stenosis and glans dehiscence occurred in each 1 case (4%) in both groups. Differences were not statistically significant. However, there were significantly more wound infections in the stented group. On the other hand, stents prevented temporary urinary retention which occurred in 2 patients in the non-stented group.

CONCLUSION

Despite the limited number of cases, our study suggests that, all in all, there is no significant difference in severe complication rates regardless whether a postoperative stent is used or not.

Non-stented versus stented urethroplasty for distal hypospadias repair: A systematic review and meta-analysis

INTRODUCTION

Studies have shown that non-stented distal hypospadias repair eliminates stent-related bladder spasm and stent removal discomfort without increasing complications; however, results are inconsistent. We performed a systematic review to assess the complication rates of non-stented compared to the stented distal hypospadias repair.

METHODS

The literature search included randomized control trials (RCTs) and cohort studies published prior to October 2016 in all languages (PROSPERO CRD42016047563). All included studies were assessed according to Cochrane Collaborative recommendations and included for meta-analysis. Surgical outcomes from each treatment group were classified according to early complications and later final outcomes. Outcomes were expressed as relative risk (RR) and 95% confidence intervals (CI). Interstudy heterogeneity was assessed using chi-square and I². Effect estimates were pooled using the inverse variant method with random effect model. Subgroup analysis was performed according to surgical technique (Mathieu versus tubularized incised plate) and study design.

RESULTS

A total of 20 studies (14 cohorts, 6 RCTs) with 2466 hypospadias repairs (1290 non-stented, 1176 stented) were included for the meta-analysis. Serious risk of bias was noted among the cohort studies with publication bias likely present, while the included RCTs were of moderate methodological quality. The overall pooled effect estimates comparing non-stented versus stented distal hypospadias repair showed no between-group difference for outcomes of early and late complications (RR 0.83, 95% CI 0.46-1.50; RR 0.96, 95% CI 0.92, 1.48; respectively) CONCLUSIONS: Current evidence of low to moderate quality suggests that there is likely no outcome difference between non-stented and stented distal hypospadias repair.