Comparison of the efficacy and safety of dorsal inlay graft urethroplasty (DIGU) method with tubularized incised plate urethroplasty (TIPU) method in primary distal hypospadias repair: a systematic review and meta-analysis

Introduction: Tubularized Incised Plate Urethroplasty (TIPU) is a technique that is widely used in distal hypospadias repair. The advantages possessed by this technique are better cosmetics, the meatus is at the tip of the penis, and the phallus is straight. Some researchers believe that a urethral plate with a size of less than 8 mm is unsuitable for the TIPU technique so augmentation with a graft using the dorsal inlay graft urethroplasty (DIGU) technique is needed. To date, there have been no systematic reviews and meta-analyses that have directly compared the efficacy and complications of DIGU and TIPU. Therefore, this study aimed to compare the effectiveness and complications of these two modalities for repair in primary distal hypospadias patients. Methods: This study is a systematic review study and meta-analysis. The protocol for conducting and compiling this study was based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A systematic search was performed on six databases: PubMed, Scopus, Web of Science, ProQuest, Cochrane Central Register of Controlled Trials (CENTRAL) and ClinicalTrials.gov. The risk of bias in the study will be analyzed using the Cochrane Risk of Bias Tools for Randomized Trials version 2 (RoB 2). Results: Six studies that met the inclusion criteria were included in the meta-analysis with a total of 381 samples. The success rates (OR 1.46, 95% CI 0.74-2.87, p = 0.28) and urine output (OR 2.54, 95% CI 0.63-10.20, p = 0.19) were not significantly different, while the mean operating time (MOT) (SMD 1.96, 95% CI 1.10-2.82, p < 0.0001) was significantly shorter in TIPU (P < 0.05). The incidence of meatal stenosis was significantly more in TIPU than DIGU significantly (OR 5.11, 95% CI 1.46-17.92, p = 0.01), while fistula (OR 2.93, 95% CI 0.92-9.35, p = 0.07) and dehiscence (OR 3.05, 95% CI 0.81-11.45, p = 0.10) was not significantly different between the two techniques. Conclusion: TIPU has the advantage of shorter operating time but a higher incidence of meatal stenosis than DIGU.