Results of the one-stage proximal hypospadias repair with modified Koyanagi technique: A prospective cohort study in a single Vietnam centre.

Introduction: Proximal hypospadias is the most severe type of hypospadias. Our approach to Koyanagi technique for proximal hypospadias aims to improve the blood supply to the neourethral flaps and reduce meatal complications.

Methods: Our prospective study included 75 patients who were operated for proximal hypospadias by our Koyanagi technique at Viet Duc hospital between January 2019 and December 2020. The clinical information obtained included a detailed medical history; preoperative, intraoperative, and postoperative data; short-term outcomes by the HOSE score were evaluated by a different physician.

Results: The mean (range) age was 3.59 ± 2.41 years (1.5-14), 86.7% under 5 years old. There are 31 penoscrotal, 31 scrotal, and 13 perineal hypospadias. The length of the neourethra ranged from 3.5 to 8 cm, mean 5.02 ± 0.88 cm. Evaluation of the surgeon at 6 months after surgery: primary success 81.3%. Complications occurred in 14 cases (18.7%), included 10 urethrocutaneous fistula and 4 dehiscence of the urethra. No cases of meatal stenosis or recession, urethral stricture, urethral diverticula. The mean HOSE score was found to be 14.47 ± 1.35, ranged 11 to 16. 57 patients (76%) had a total HOSE 14 and above and 18 patients had score below 14 (24%).

Conclusion: Our modified Koyanagi technique give us a good result for one-stage reconstruction of proximal hypospadias. Applying the HOSE score makes postoperative evaluation of hypospadias more objective and reliable.