The Monti principle in continent urinary diversion

Karl J. Kreder

doi:10.3109/9780203341025-37

The Mitrofanoff principle has been extensively discussed in Chapter 26. The appendix remains the first choice for the Mitrofanoff tube, because of its supple nature, adequate lumen and reliable blood supply.1 However the appendix is not always available because of scarring, short length, poor blood supply, or previous surgical removal.2,3 Furthermore many patients with neuropathic bladder also have bowel problems in the form of constipation and or incontinence. With the popularization of the Malone Antegrade Continence Enema (MACE) procedure to treat the above, the appendix may be less available and therefore other alternatives are required for the Mitrofanoff procedure.4,5 Since Mitrofanoff described his procedure in 1980,3 using the appendix, several other options and modifications of continent catheterizable conduits have been described.6-9 The different structures used for these techniques include: ureter, longitudinally tapered ileum, large bowel, bladder, stomach, fallopian tube, vas deferens and prepucial skin. Adequate vascularity, mobility and lumen size have been difficult to achieve with the above and many are surgical curiosities without clinical relevance.10,11 Yang was the first to describe the technique of transverse retubularization of the ileum to create a continent catheterizable conduit, using the needle tunneling technique.6 In 1997, Monti et al developed this technique further to create a neo-appendix in a canine model.7 Two alternative techniques were described, where a single or two small ileal segments were opened longitudinally and retubularized transversely to create a small caliber conduit. In the canine model the tube was continent, easily catheterizable and the main complication was stomal stenosis attributed to infrequent catheterization. Since then this procedure has been studied in the clinical setting, and successful outcomes have been reported.1,2,9-13 In addition, further modifications of the initial Yang-Monti technique have been introduced and evaluated.14,15 The Yang-Monti principle The Yang-Monti principle creates a ‘neoappendix’ using a segment of ileum. The principle involves the following: ■ isolation of a short segment of ileum (2-4 cm), which is usually freely available, and has good mobility and blood supply (Figure 28.1a). The circumference of the bowel used will determine the tube length ■ detubularization along the longitudinal axis with transverse retubularization, after which the mucosal folds are rearranged longitudinally facilitating easy catheterization (Figure 28.1b) ■ no mesentery is left at the ends of the tube aiding creation of a continence mechanism and transit through the abdominal wall (Figure 28.1c) ■ the continence mechanism is created by implantation of the tube into the bladder using a submucosal tunnel or by imbricating the tube in a bowel wrap ■ the length of the bowel segment isolated (2-4 cm) will determine the diameter of the refashioned tube (1 cm or 14Fr). Longer segments will result in a wider channel for catheterization, but will also require a longer tunnel in the bladder because of its bulk ■ if the length of the single Monti tube is not adequate, two Monti tubes can be joined together ‘The Full Monti’ (Figure 28.2) ■ when a concomitant ileocystoplasty is created, the adjacent bowel segment is used for the Monti tube, obviating the need for additional bowel anastomoses.

The Monti principle in continent urinary diversion

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