Page 107 - Manual of Equine Field Surgery

•

CHAPTER 17

Semitendinosus Tenotomy and Myotomy

Joanne Kramer

the affected limb positioned down. The myotomy
INDICATIONS procedure is performed with the horse standing

with local anesthesia and sedation.
Treatment of gait abnormalities secondary to

fibrosis or ossification of the semitendinosus

muscle (fibrotic myopathy).
PROCEDURE

EQUIPMENT Semitendinosus Tenotomy

Palpation of the proximal medial tibial region

No special equipment is required for tenotomy. A usually reveals the location of the horizontally ori-

blunt-tipped bistoury is useful for the myotomy ented tendon of insertion. Generally, the tendon

procedure. is about four fingers' width distal to the proximal

tibia. The distal end of the tibial crest can also be

used as a proximal to distal guide. An 8-cm verti-
ANATOMY

cal incision is made over the tendon caudal to the

medial saphenous vein. The incision is extended
The semitendinosus muscle originates from the through the subcutaneous tissues and the dense

transverse processes of the first and second caudal crural fascia to expose the tendon. Curved forceps

vertebrae, the sacrosciatic ligament, and the are passed underneath the tendon, and the tendon

ventral surface of the ischiatic tuberosity. It inserts is transected (Figure 17 -1). The fascial layer is

on the tibial crest, crural fascia proper, and cal- closed with an interrupted or continuous pattern

caneal tuberosity. The tendon of insertion on the using synthetic absorbable suture material.

medial aspect of the proximal tibia is transected The subcutaneous tissue is closed with a continu-

in the tenotomy procedure. The myotomy proce- ous pattern using synthetic absorbable suture

dure involves transecting muscle fibers at the material. The skin is closed in an interrupted

distal extent of the fibrotic region and is typically pattern.

performed on the caudal aspect of the limb just

proximal to the musculotendinous junction.

Semitendinosus Myotomy

POSITIONING AND PREPARATION Infiltration of local anesthetic is performed in

an inverted-U pattern surrounding and distal

The semitendinosus tenotomy procedure is per- to the most taut palpable area of fibrosis. A 6-cm

formed with the horse in lateral recumbency with vertical incision is made over the caudal aspect

103