First described in paediatrics, the formation of a catheterisable channel utilising the Mitrofanoff principle has been used for the past few decades in adult populations.  The optimal site for the exit stoma of a Mitrofanoff or Monti channel remains unknown. In children there is evidence that the iliac fossa may be a superior site. Our aim was to examine a large adult cohort of patients having creation of a continent catheterisable channel for a variety of indications to elucidate the presence, if any, of an optimal exit stoma site in adults.

We performed a retrospective case note review of 176 consecutive adult patients (median age 42 years) having Mitrofanoff channel formation a median of 142 months (range 54-386) ago. We evaluated outcome in terms of stoma site revision, channel revision, continued use and continence for each stoma exit site. Statistical analysis was by Chi Squared analysis.

The 176 patients had a median of 51.5 months (range 2-339) follow-up available. At the time of this review 165 (93.8%) patients were alive.  At the time of last follow-up 76% of channels were in use and 69% were continent.

Outcomes at last clinic follow-up are listed in table 1 below. In total 69% (n=121) had their exit site located at the umbilicus while 29% (n=50) were located in the right iliac fossa and 2% (n=4) in the left iliac fossa. Patients with their stomas located in the right and left iliac fossae were younger than those with their stomas located at the umbilicus. Skin level revisions were lowest in the cohort with umbilical exit sites with 55% (n=66) of these patients undergoing a skin level revision compared to 72% (n=36) of those with exit sites in the right iliac fossa and 75% (n=3) of those with exit sites located in the left iliac fossa. The details regarding one stoma's exit site could not be determined from the notes and the patient had died during follow up.

Umbilical stomas for Mitrofanoff channels are formed significantly more often than stomas in other locations such as the right or left iliac fossae. The site of Mitrofanoff exit stoma did not affect channel usage and continence at last follow up.   Location of the exit site of a continent catheterisable channel will of course be affected by other factors such as body habitus and prior abdominal surgery but we propose that given the significantly lower rate of skin level revision at an umbilical exit site that this may be the better location in adults.