Use of the rectus abdominis muscle for abdominal stoma sphincter construction: An anatomical feasibility study

Permanent fecal abdominal stomas significantly decrease quality of life. Pr evious attempts to create continent stomas by using dynamic myoplasty proce dures have resulted in disappointing outcomes, primarily owing to denervati on atrophy of the muscle flap that was used in the creation of the sphincte r and because of muscle fatigue resulting from continuous electrical stimul ation that is received by the flap to force contraction. On the basis of th ese problems, we designed two separate studies: an anatomical study address ing flap denervation and a functional study addressing muscle fatigue. The present study addresses the first topic and was designed to develop a rectu s abdominis muscle flap into a sphincter that was anatomically situated to create a stoma while preserving as much innervantion as possible. In 24 rec tus abdominis muscles of human cadavers, the neurovascular anatomy was defi ned, then the anatomical feasibility of two different muscle flap configura tions was considered. The flaps investigated were the peninsula flap and is land flap designs, with both using the most caudal segment of the rectus ab dominis muscle in construction of the sphincter. Neither flap design requir ed the killing of a nerve for stoma sphincter creation, resulting in minima l muscle denervation. The conclusion of our comparison was that the above, in conjunction with other features of the island flap design, such as muscl e overlap after sphincter formation and abdominal wall positioning of the s phincter, made the island flap design better suited to stoma sphincter cons truction.