Applications of a semitendinosus muscle flap in two dogs

T he technique of using vascularized muscle flaps for repair or replacement of lost tissues can be used in companion animal surgery as it has been in human surgery for many years.Knowledge of the vascular anatomy of the muscles is paramount to their use as perfused flaps, 1 and a recent study has been performed to ascertain the number, location, and relative importance of the vascular pedicles to the pelvic limb muscles in the dog. 2 We have treated 2 dogs at the teaching hospital, using the proximal end of the semitendinosus muscle as a vascularized flap.The first case involved a 6-year-old male German Shepherd Dog with a recurrence of perineal hernia.Bilateral herniorrhaphy had been performed 2 weeks earlier.Internal obturator muscle flaps had been elevated to reinforce bilateral weakness, but mobilization of the muscles was complicated by malunion of an old ischial fracture.A ventral hernia could only be partially repaired by joining the internal obturator muscles at the midline.The ventral hernia recurred, causing feces to accumulate in a rectal sacculation.Dysuria also developed that was attributed to the abnormal pelvic diaphragm, because other causes were ruled Out with radiographic and urodynamic studies.During the second operation, a left semitendinosus muscle flap was used to fill and repair the ventral hernia.A skin incision was made along the caudal border of the ischiatic tuberosity and continued distally along the caudal aspect of the left thigh to the distal on e third.The left semitendinosus muscle was dissected from surrounding structures and the proximal vascular pedicle was identified.The muscle was transected at midbelly, and the origin was partially elevated by incising the lateral portion of its tendinous attachment to the ischium to allow further mobilization .It was then rotated beneath the anus, and the original medial border was sutured to the ventral aspect of the external anal sphincter with interrupted cruciate stitches (Fig 1) .The distal end of the flap was sutured to the right internal obturator muscle, which