Technical Details
In the majority of cases a Mitrofanoff channel is constructed through a midline infraumbilical incision. If the patient will only have a continent vesicostomy constructed, the right laterovesical space is deeply freed before opening the peritoneum. The cecum and appendix are explored and the pedicle vessels of the appendix are carefully mobilized. The appendix is excised from the cecum with a cecal wall cuff. The aim in leaving the cecal cuff on the appendix is to enable a wide anastomosis on the abdominal wall. Once the cecal defect is closed, the tip of the appendix is opened obliquely, the lumen is irrigated with
- Fig. 34.1 (A-D) Submucous tunnel technique into the U-flap of thick-walled bladder for creating a Mitrofanoff channel
an antiseptic solution, and the patency of the lumen is checked with a catheter. If the bladder has a small capacity and thick wall (as it has most of the time), a U-shaped flap should be raised cranially for entrance. With the help of this flap, the appendix can be anastomosed to the bladder through a long tunnel (Fig. 34.1). The tunnel should at least be 2.5-3 cm long. Once the conduit-bladder anastomosis is completed, if no further procedures such as bladder augmentation, bladder-neck reconstruction, or ureteric reimplantation are necessary, the bladder is closed and the conduit is anastomosed either to the right lower quadrant or to the umbilicus. In the literature, two cases have been reported to have their appendix located into the left lower quadrant due to previous stomas created in the right lower quadrant. In these cases the cecum and the ascending colon were widely mobilized, the appendiceal vessels were dissected up to their origin from the superior mesenteric artery, and the conduit was moved to the left through a defect created in the bowel mesentery and anastomosed to the left abdominal wall [44].
In the majority of patients, augmentation cysto-plasty is a part of this surgery. Augmentation provides a low-pressure reservoir, while the Mitrofanoff channel aids in emptying the reservoir regularly. The bladder neck should be constructed or closed so that it does not leak. It has been shown in many cases that even though vesicoureteric reflux may exist in the system, the creation of a low-pressure reservoir and guaranteeing regular emptying of the system will lead to disappearance of the reflux. Thus, in many patients with small bladders and limited space for a ureteric reimplantation, the reimplantation should not be carried out and morbidity is avoided [45].
In patients with urethral injuries as a result of ARM repair, if a long and complicated management is necessary, or if autoaugmentation is indicated for a different underlying pathology, it is appropriate to construct an appendicovesicostomy without opening the bladder. In the extravesical Mitrofanoff technique that we use in our patients, the abdomen is entered through a lower-abdominal midline incision, the right laterovesical space is opened, and a Lich-Gre-
- Fig. 34.2 (A-D) Extravesical Mitrofanoff technique
goire-like extramucosal tunnel is created in the right posterolateral wall of the bladder. The mucosa is entered close to the bladder neck and an appendicovesi-costomy performed. The seromuscular layer is closed with sutures, the tunnel is completed, and the appendix is anastomosed to the skin (Fig. 34.2). In cases where the appendix is not available or has been used for the MACE procedure, the Mitrofanoff channel is most commonly created using the Monti technique [46]. Although this technique was described by Monti in 1997 [47], it was also described by Yang in 1993 [48]. When Yang reported this technique, however, he focused on the use of a needle as an aid for reimplants into the small bowel submucosa. In the Monti technique a 2.5-cm segment of the small bowel is detubu-larized longitudinally and retubularized transversally. A 2.5-cm segment of bowel provides a tube size of about 18-20 Fr. The length of the Monti tube is determined by the diameter of the bowel segment. The length will be at least 8 cm when the ileum is used and 10-12 cm when the colon is used. The transverse tubularization should be carried out first with muco-sal apposition and then with a second row of serosal sutures [48]. Problems such as kinking, diverticula formation, and catheterization problems observed after longitudinal tubularization of ileal segments are rarely reported in Monti tubes [49]. Stomach and colonic tubes can be used for the same purpose [50]. The common pedicled bowel segment can be used in patients in whom bladder augmentation needs to be combined with an ileal Monti.
Two Monti tubes can be anastomosed to each other or elongated in a spiral fashion, similar to the construction of longer channels, creating a double Monti [51]. In addition, in both the Mitrofanoff and MACE procedures, longer tubes may be created using combinations of the appendix and Monti tube or appendix and cecal tube [52,53]. Rink created a continent cath-eterizable vesicostomy by modifying Casale's vesicos-tomy with an antireflux technique. Stomal continence was achieved in all patients with this technique, but 45% have required revision due to stomal stenosis. Thus, the use of the technique has been limited to large bladders requiring continent vesicostomies [54]. In a patient with microcolon-intestinal hypo-peristalsis syndrome, a bladder tube created from the posterior wall of a huge, adynamic bladder has been used with success and no morbidity [55]. A salvage continent vesicostomy has been created in five children with enterocystoplasties and no appendix, using a bladder tube created completely extraperitoneally, and plicated with the bladder at its base in a Nissen-like fashion to add an antireflux property [56].
Minimally invasive techniques, although not widely popularized, have been used in the construction of continent urinary channel surgery. The first laparoscopic appendiceal-vesical anastomosis with a flap-valve mechanism has been reported by Hsu and Shortliffe [57]. There is also a case report on laparoscopic removal of a nonfuctioning kidney and anastomosis of the distal ureter to the skin as a continent channel in a patient who had previously undergone a ureteric reimplantation due to vesicoureteric reflux [58].
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