Is it possible to use the rectus abdominis neo-sphincter as a continence mechanism for urinary catheterizable channels? A histologic and histochemical evaluation in an experimental study in rabbits

ObjectiveTo evaluate in a rabbit experimental model a mechanism of continence of catheterizable urinary conduits (CUC), focusing on the behavior of intersected rectal muscle fibers in relation to the channel by histological and histochemical analysis, and secondarily to register conduit continence rates from clinical and urodynamic data.Materials and methods12 rabbits were submitted to construction of a CUC from two abdominal skin flaps and divided into two groups: 8 with a urinary neo-sphincter created according to Yachia and 4 controls. We registered clinical outcome, urodynamic studies and microscopic analysis of CUC on the surface of the conduit, which was in direct contact with the mechanism of continence. We took muscle samples from the mechanisms of continence and performed histochemical evaluation by enzymatic reactions.ResultsHistological evaluation of the CUC showed no difference between groups. Histology and immunohistochemistry of the muscle fibers showed that areas of necrosis, cell atrophy and motor neuron injury from the first eight weeks recovered by the end of 16th week. Conduit complications occurred in 4 animals (33%). The average detrusor leakage point pressure through the conduit was 90 cm H2O versus 39 cm H2O through the urethra.ConclusionThe mechanism of continence did not promote ischemic stress on the conduit, was able to promote high pressure resistance and showed good recovery of intersected muscle fibers, after an initial slight atrophy, suggesting good durability of the neo-sphincter.