Long-term functional outcomes of distal hypospadias repair: a single center retrospective comparative study of TIPs, Mathieu and MAGPI.

INTRODUCTION: Tubularized Incised-Plate (TIP) urethroplasty is currently the preferred technique for distal hypospadias repair. Nevertheless, concerns have been raised on the long-term functionality of the reconstructed neourethra.

OBJECTIVE: The aim of this study is to evaluate long-term uroflowmetry parameters' evolution after TIP surgery over a long-term follow-up including the adolescent period. TIP patients were compared to normal children using established Miskolc nomograms, as well as to patients who underwent Mathieu and Meatal Advancement and Glanuloplasty (MAGPI) surgery repairs for distal hypospadias.

STUDY DESIGN: Files from patients who underwent primary distal hypospadias repair at our institution between January 1, 1997 and January 31, 2001 were reviewed. Only patients with documented serial postoperative uroflowmetry profiles at follow-up visits were included. Comparison between surgeries (TIP vs. Mathieu vs. MAGPI) was performed according to the following postoperative time interval endpoints: 0-6 months, 6-12 months, 12-24 months, 24-48 months, 4-6 years, 6-10 years and >10 years. Maximal urinary flow rate (Qmax) in relation to Voiding Volume (VV) adjusted for Age or Body Surface Area (BSA) were also evaluated in comparison to normal children using established Miskolc nomograms and compared between surgery techniques.

RESULTS: 153 patients met the inclusion criteria: 70 (43%) TIP, 24 (17%) Mathieu and 59 (35%) MAGPI. Overall, Qmax increases progressively according to time and age and in particular during the period covering adolescence with a similar trend regardless of the type of surgery. Uroflowmetry profiles in terms of Qmax, VV and PVR were equivalent between surgeries at each examined time point. At 10 years of follow-up postopertively, mean Qmax were 17.2 ml/s, 18.8 ml/s and 21.6 ml/s respectively with no significant difference detected between groups (p = 0.344). Compared to normal children when adjusted for voiding volume and BSA, the proportion of obstructive uroflowmetry patterns defined as Qmax< 5th percentile of nomograms was more prevalent in patients aged 2-7 years old at 60% but decreased to less than 10%in patients aged >13 years for all procedures combined (see abstract figure) but without detected differences between surgery types (p = 0.276).

DISCUSSION: After sub-optimal obstructive maximal urinary flows in the early postoperative period, hypospadias patients treated with TIP exhibit favourable long-term evolution with age and during adolescence in particular compared to normal children. In addition, a similar trend was found for patients treated with Mathieu and MAGPI with no significant differences detected between procedures. Nevertheless, because of the relatively small sample size we cannot exclude that a statistical difference between surgeries would have been detected if the study was adequately powered on every endpoint. Nevertheless and also as suggested by the values obtained, this potential difference may be quite small and not clinically relevant.

CONCLUSION: These results suggest that the obstructive urinary flow pattern observed in patients early on is possibly an intrinsic feature associated to the malformation itself and may be less of a consequence of the surgical technique.