A new extra-abdominal channel alternative to the Mitrofanoff principle: experimental and preliminary clinical experience.

INTRODUCTION The appendix is the gold-standard channel for the Mitrofanoff principle in pediatric urology, but the search for alternatives is justified considering it may not be available or preferably used for colonic stomas (Malone antegrade continence enema). The aim of this study is to report on technical feasibility of a new approach for creating catheterizable channels in a rabbit model and to present our preliminary clinical experience. MATERIAL AND METHODS We configured a tube from two rectangular skin flaps 1x4 cm opposite each other in the middle line of the lower inferior abdomen. The channel was anastomosed to the bladder dome with embedding sutures to create a valvular mechanism. The experimental study consisted of 12 rabbits, divided in 4 groups according to the sacrifice schedule at 2, 4, 8 and 12 weeks. At 30th postoperative day, an urodynamic evaluation was performed to record continence of the stoma. A histological analysis of the specimens stained with hematoxylin-eosin, Masson trichrome and Picrosirius red was also done in group 2 (sacrifice at 4 weeks postoperatively). We used this method in 3 patients with congenital non-neurogenic bladder disease presenting with massive residual volumes without compliance deficits. RESULT The technique proved feasible in all animals, 9 of 12 could be easily catheterized and underwent urodynamic study. No stoma leakage was observed in 7 animals at high bladder pressures (> 50 cm H20) and only 2 animals had some leakage at 40 cm H20. Urodynamics performed through the stoma showed urethral leakage at 20 cm H20, therefore demonstrating the efficacy of the valvular mechanism. Histological analysis confirmed good integration between the tube and the bladder. Mean follow-up of the clinical series (3 patients) was 7.2 months. Two patients remained continent up to 4 hours, whereas 1 patient had some leakage after 2 hours. CONCLUSION We were able to confirm feasibility of a new extra-abdominal channel based on the Mitrofanoff principle and successfully reproduced the method in a clinical setting. Follow-up was short and long term results are required before any conclusive judgment can be made.