Tenoscopic release of the equine carpal canal

OBJECTIVE: To develop a tenoscopic method to divide the carpal flexor retinaculum and decompress the carpal canal. STUDY DESIGN: Cadaver specimen study and prospective trial. ANIMALS: Twelve cadaveric limbs, 4 clinically normal horses, and 2 clinically affected horses. Methods-A tenoscopic approach to the proximolateral aspect of the carpal sheath was used to identify and facilitate endoscopic division of the inner and outer layers of the carpal flexor retinaculum in cadaver limbs. The technique was further evaluated in 4 normal and 2 clinically affected horses. RESULTS: Anatomic dissection, intraoperative observation, necropsy, histologic evaluation, and both short- and long-term clinical follow-up indicate that a tenoscopic approach that divides the inner layer of the carpal retinaculum can successfully decompress the equine carpal canal. No iatrogenic damage to surrounding structures was evident, division of the retinaculum was adequate and permanent, and clinical morbidity was negligible. Resolution of effusion was evident in both clinical cases of carpal canal syndrome and lameness resolved in the 1 horse in which long-term follow-up was possible. CONCLUSIONS: Tenoscopic release of the carpal flexor retinaculum could provide a minimally invasive method to quickly, safely, and effectively decompress the carpal canal. CLINICAL RELEVANCE: Tensocopic release of the carpal flexor retinaculum is a safe alternative to open division of the retinaculum to decompress the carpal canal in horses with carpal canal syndrome.