Mitrofanoff principle – implanting a supple tube within a submucosal tunnel, with good muscular backing. During reservoir filling the pressure should coapt the catheterisable channel to provide continence.
Usually use appendix but can use transversely tubularised bowel segments (Yang-Monti).
Technique:
- Bowel prep
- Midline laparotomy
- Mobilise the right colon and caecum
- Remove the appendix with a cuff of caecum to provide length
- Close caecum with PDS in two layers
- Preserve the appendiceal artery but mobilise the mesoappendix as necessary to reach stoma without tension
- Open appendiceal tip and ensure appendix can be catheterised
- Open bladder – clamshell or U shaped flap to allow Boari if needed
- Distal appendiceal tip is used in bladder end – minimal 2 cm submucosal tunnel length (utilising clamshell), usually posterolateral (depending on stomal site)
- Key points:
- Keep channel as short as possible for ease of catheterisation
- Avoid kinking
- Continually catheterise the channel at each step
- Spatulate the proximal end of the appendix and make a skin flap at the intended site (umbilicus or RIF)
- Mature with interrupted absorbable sutures
- SPC and catheter in Mitroffanoff. Leave for 3 weeks, cystogram, and then commence self catheterisation with SPC remaining in until catheterisation is good.
Complications:
- Stomal stenosis or skin closure
- Difficulty catheterising – at level of skin, fascia or entry to bladder
- Incontinence
- Necrosis
Useful properties of the appendix:
- Easily and safely harvested without morbidity
- Small calibre permits functional continence / submucosal tunnel
- Longer relatively in children and kids have thin abdominal walls
- Reasonably mobile blood supply
Yang-Monti principle for using small segment of ileum if appendix is unavailable:
- 2 – 3 cm ileum harvested on pedicle
- Opened longitudinally on antimesenteric border and closed transversely over a catheter
Other option – longer segment of ileum, with stapler used to taper ileum diameter to that of a catheter.