In the classical MACE technique, following effective bowel preparation and under the protection of broad-spectrum antibiotics, the appendix pedicle is mobilized, the blind tip is opened, the appendix is detached from the cecum, inverted, and is anastomosed to the cecal mucosa after being passed through a submucosal tunnel formed on the taenia. The seromuscular layer is closed on top to form an antireflux mechanism. The procedure is completed following cutaneous anastomosis. It is essential to suture the cecum or colon to the back of the anterior abdominal wall and not to leave a free intraperitoneal part of the conduit . Multiple modifications of this original technique have been reported many times (Table 34.2). If the appendix is not available or has been previously used as a Mitrofanoff channel, ileal, colonic, or gastric Monti channels can be used to create an ACE. The cecum, transverse colon, left colon, and stomach tubes have been used in ACE construction. The left colon antegrade continence enema (LACE) procedure has been reported to have advantages by providing gravity-assisted evacuation, avoidance of the right and transverse colon, which has a large-volume capacity, a convenient stoma location in the left upper quadrant, shortening of the enema duration, a smaller fluid volume, and no ACE related abdominal pain. In the left colon, laterally or medially based tubes are used with either in situ flap-valve mechanisms or placement of a Monti tube in a submucosal tunnel along the colon taenia to form an antireflux mechanism [64-69]. The indications to perform a right or left colonic Monti-MACE procedure are: previous appendectomy, previous appendicovesicostomy, inadequate mesentery associated with the appendix, previous ileocecal augmentation, and obliterated appendicocecostomy . Other modifications are based on similar indications.
In the MACE procedure, different antireflux techniques are used. In cecal imbrication (cecal wrap technique) the appendix is not detached from its base. An antireflux mechanism is developed in a similar fashion to Nissen's fundoplication around the in situ appendix (Fig. 34.3) . In cases in which the ileocecal pouch reservoir has been created as a continent urinary diversion, a technique involving the reinforcement of the imbrication of the in situ appendix with a mesh has been reported . In the extramucosal seromuscular taenial tunnel technique, analogous to the Lich-Gregoire technique, the seromuscular layer of the taenia is incised without opening the mucosa. On the distal part of the incision, the mucosa enema
Disconnection and reimplantation of the appendix Orthotopic appendicostomy (+/- divided appendix) Tubularized cecal/colonic flap Transverse tubularized ileal tube (Monti) Laparoscopic MACE (Appendicostomy only) Cecostomy button Percutaneous cecostomy catheter LACE
is opened and the conduit is anastomosed to the ce-cum. The antireflux mechanism is created by covering the conduit with the seromuscular layer (Fig. 34.4). The application of the Monti channel to the ileocecal pouch involves similar technical aspects .
The intraluminal reimplantation technique involves the creation of a submucosal tunnel, similar to Cohen's reimplantation technique, and placement of the conduit into this tunnel. This technique is preferred in cases where bladder substitutes are constructed and the conduit needs to be anastomosed to the bowel (Fig. 34.5). The construction of a direct appendicostomy without supportive antireflux techniques have been reported mostly by authors using laparoscopic techniques, who state that it reduces the risk of conduit incontinence. On the contrary, Malone has reported stomal incontinence for gas and feces in all six cases in whom he performed a direct appendicostomy . Lynch et al. report a 6.7% leakage rate in 28 patients with laparoscopically performed continent cecostomy and state that this is not a higher rate compared to those who have an additional antireflux procedure . Similarly, van Savage et al. have reported no stomal leakage in 16 laparoscopically performed procedures. Their statement is that the continence mechanism is simply a function of the length of the appendix and the mucosal coaptation of the appendiceal lumen . In the majority of cases that develop leakage, a surgical revision is necessary. In our series, a mild leakage was managed by submucosal injection, and in Mitrofanoff's series an artificial urinary sphincter application was beneficial in one case .
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