Direct sphincter repair provides good results in the majority of patients suffering from fecal incontinence. Muscle transposition is reserved for cases in which direct repair cannot be accomplished because of lack of sphincter muscle from severe trauma, congenital anomalies, or because of denervation of the sphincter.

The gluteus maximus muscle is an ideal candidate for transposition to the anal canal for sphincter reconstruction. As opposed to other muscles used for transposition for fecal incontinence, the gluteus maximus muscle is a strong, thick muscle with a generous blood supply. It originates from the upper portion of the ileum, the sacrum, and the coccyx and then inserts into the femur and iliotibial tract. The origination of the gluteus muscle from the posterior pelvic structures causes the greatest squeeze pressures to occur against the anterior wall of the rectum in gluteus maximus muscle transpositions. This directional squeeze mimics the physiologic action of the external anal sphincter and may assist in the maintenance of continence by crimping the anal canal. Also, the thickness of the gluteus maximus flap can lengthen the anal canal and its high-pressure zone once transposed. The generous blood supply to the muscle is from the superior and inferior gluteal arteries and is supplemented by the branches of the medial and lateral femoral circumflex arteries. The gluteus maximus muscle’s close proximity to the anus also makes it advantageous for transposition as it is a synergist for the external anal sphincter; contraction of the gluteus maximus muscle is a natural response to impending fecal incontinence. Postoperative studies of gluteus maximus transpositions show tonic activity, and in some studies, there is an increase of not only postoperative squeeze pressures but also resting pressures. This basal tone may be secondary to the use of the gluteus maximus muscles during walking. In addition to recovered motor function, rectal sensation also improves after this operation. Encirclement of the anus with voluntary muscle allows the rectum to become distended. The patient is able to recognize the rectal distension and evacuate in a controlled fashion.

Several absolute and relative contraindications exist for the creation of gluteus maximus transposition. Motor innervation to the gluteus muscle is from the inferior gluteal nerve (L5, S1, S2). Fecal incontinence caused by central cord malformations such as spina bifida may be associated with dysfunction to the gluteus maximus muscle also. Therefore, a more proximally innervated muscle transposition may be a better
choice for treating these conditions. Another contraindication is the lack of a distensible rectum secondary to extensive inflammation or injury. In order for the gluteus maximus transposition to work, the patient must have a compliant reservoir to distend in order to improve control. Relative contraindications suggested by some investigators include prepubescent youths and adults greater than 60 years old. These same investigators have had their worst outcomes in patients with congenital malformations followed by patients with severe pudendal neuropathy.