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

ABSTRACT 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.

摘要 研究目的：海绵体成形术（Spongioplasty）——即对分叉发育不良的远端尿道海绵体两分支进行游离并中线靠拢，可作为新尿道（neourethra）的覆盖层，以预防尿道下裂（hypospadias）修复术中出现尿道皮肤瘘（urethrocutaneous fistula）。但目前尚不明确海绵体成形术是否会对新尿道功能产生影响。本研究旨在对比开展与不开展海绵体成形术的尿道下裂修复术后新尿道的功能差异。
材料与方法：将14只先天性尿道下裂新西兰雄性家兔随机分为两组，每组7只。实验组采用Duplay尿道下裂修复术联合海绵体成形术，对照组仅实施Duplay尿道下裂修复术。通过对比新尿道顺应性与尿流流速，评估两组间的功能差异。术后2个月，对分离得到的新尿道节段，使用数字压力计测量管腔内压力，分别以1mL、2mL、3mL空气进行渐进性扩张，以此评估在体新尿道顺应性。随后获取阴茎组织，采用简易装置完成尿流率（uroflowmetry）检测。
结果：术后对照组与实验组分别有1只、0只家兔发生尿道皮肤瘘。实验组的平均管腔内压力高于对照组（分别注入1mL、2mL、3mL空气时，压力依次为82.14 vs 69.57、188.43 vs 143.26、244.71 vs 186.29mmHg），但该差异未达到统计学显著性水平。两组的平均尿流流速亦无显著差异（2.93mL/s vs 3.31mL/s）。
结论：在本先天性家兔模型中，开展与不开展海绵体成形术的尿道下裂修复术后重建尿道，未发现明显的功能差异。