Evaluation of myectomized partial-thickness ileum in experimental bladder augmentation.

Abstract

BACKGROUND: We undertook this study to examine the effects of 'stripping' with excision of serosa and muscularis propria (myectomy) from the antimesenteric aspect of ileum incorporated into the urinary tract. METHODS: Two groups of five dogs were studied. In the first group studied, detubularizing was effected by incising the middle of the thinned antimesenteric aspect of the ileal wall longitudinally. Myectomized bowel was then anastomosed to bladder as a patch-type augmentation cystoplasty. Omentum was applied to denuded surfaces. In the second group of dogs, two isolated segments of ileum were anastomosed to bladder to form cornua with ureters implanted into the cranial ends. One of the two cornua was myectomized as above and, in three of the five dogs, the denuded surfaces were covered by omentum. RESULTS: In the first group, no contraction waves were recorded during filing. In the second group, myectomized segments with adherent omentum were acontractile with low intraluminal pressures and were considerably more capacious compared with control segments and those not omentally wrapped. Ureteric thickening and dilatation were present in all upper tracts proximal to control cornua and myectomized segments not covered by omentum. None of the upper tracts in the first group or above the omentally applied segments in the second group was dilated. Adhesions and back-to-back scarring were seen in stripped bowel which had not been covered by omentum per-operatively. CONCLUSIONS: These findings indicate that myectomy of the antimesenteric aspect of ileum provides a voluminous low-pressure urinary reservoir. Careful application and fixing of omentum to denuded surfaces appears important, it ensures these features by prevention of scarring and adhesion formation.