One Stage Modified KOYANAGI-HAYASHI Technique with Tunica Vaginalis Intermediate Layer for Severe Hypospadias Surgery

Introduction: In recent years, the modified Koyanagi-Hayashi technique has attracted considerable interest due to its satisfactory results and low risk of major postoperative complications for the patient during surgery for severe hypospadias. The aim of this work is to evaluate this technique and compare our results with those of other research series. Materials and methods: A single-center prospective study of an inhomogeneous series of 32 children with proximal hypospadias and a mean age of 44 months was operated on by the same surgeon using the Koyanagi-Hayashi technique. Preoperative hormonal stimulation with testosterone was indicated in 17 children. The tunica vaginalis was used as the urethroplasty covering plane for all patients. Functional results were assessed, and a questionnaire was completed to evaluate the functional and aesthetic satisfaction of the parents and the surgeon. Results: Complete curvature of the penis was obtained in all patients except 2, who retained a minimal curvature, not requiring surgical correction at this time. There were 6 cases of urethral fistula, 2 cases of total urethroplasty release, 2 cases of partial release, 9 cases of glanduloplasty release, one urethrocele, and 2 meatus strictures. Overall, the success rate after the first procedure was 31.20%, rising to 74.95% after the first repeat procedure and 84.32% after the second. The result was very satisfactory for the parents at 84.37% and satisfactory at 15.62%. Conclusion: The Koyanagi technique modified by Hayashi is a good alternative for severe forms of hypospadias. Correction of the curvature of the penis is generally achieved without further procedures, and the aesthetic result is generally satisfactory. Using the tunica vaginalis as an intermediate plane to cover the urethroplasty has greatly reduced the rate of serious complications. The complication rate is high, and parents need to be aware of the risk of repeat surgeries. But these complications are always easy to manage