**3.5 Yang-Monti**

In 1993, Yang described the transversal tubularization of two previously detubularized intestinal ileal segments [25]. This technique, however, was only popularized in 1997 by Monti et al. who described its use in dogs [26].

The Monti conduit became a very important option especially in patients who are candidates for a catheterizable channel but have already undergone apendicectomy [12,15,19,26].

### **3.6 Surgical technique**

The most important aspect for the length of the channel is the width of the abdominal wall, which should be measured in advance with the aid of a long needle [25]. The conduit short arm must be equivalent to this length. It is important to keep in mind that the diameter of the intestinal loop and not its length is the factor that is going to determine the conduit final length [27]. To obtain a longer conduit, two ileal detubularized tubes in sequence may be anastomosed [26].

In order to avoid complications secondary to malabsorption of vitamin B12 the final 15 cm of the ileum are spared [27]. A 2-2.5 cm long intestinal segment is isolated along with its vascular pedicle. This length will allow the passage of a 16F catheter. Intestine is opened longitudinally and the distance from the incision to the mesentry should be equal to the one anticipated for the conduit short arm. The segment is then tubularized transversally over a 12-14F catheter using absorbable suture [26,27,28].

Double conduits can be made of 4-5 cm of intestinal segment. Four sutures (2 at each end of the segment, one at the mesentry and the other at the anti mesenteric border) allow adequate traction and division of the intestinal loop. The two segments are incised 5 mm from the mesentry border and sutured together by the short arm with separate sutures to avoid stenosis. Tubularization is carried out in the same fashion as for single conduits. The centrifuge circulation guarantees proper perfusion and allow tailoring of the distal ends of the conduit in case it is too long [27].

The reservoir should be anchored to the deep surface of the abdominal wall immediately adjacent to the point where the channel was implanted in order to provide stability, avoid reservoir migration and conduit kinking. As mentioned for the Mitrofanoff procedure, a Foley catheter should be placed at the end of the procedure through the conduit associated with a suprapubic cystostomy [26].

On the first post operative day, irrigation of the reservoir using the suprapubic catheter is started to reduce mucus plug formation. Within 3 to 6 weeks the conduit Foley catheter is removed, cystostomy is clamped and CIC is commenced. Once the patient is familiarized with the procedure and is fully adapted suprapubic cystostomy is removed definitively [25-27,29].

From: Gerharz EW, Tassadaq T, Pickard RS, Shah PJ, Woodhouse CR, Ransley PG. Transverse retubularized ileum: early clinical experience with a new second line Mitrofanoff tube. J Urol 1998; 159: 525-528.
