A. Tnibar, M. T. Christophersen and C. Lindegaard Equine Veterinary Education March 2010 22 3 141 - 145 This retrospective study describes ultrasound guided desmotomy of the accessory ligament of the deep digital flexor tendon in 35 cases, and a modification of this procedure using an adapted surgical instrument. The procedure was successful in 97% of cases. Wound healing was excellent in all except 4 cases. Corrective shoeing prior to surgery contributes to success. The procedure can be performed on the standing horse and offers the advantages of minimally invasive surgery which include: reduced incision length, reduced morbidity and improved cosmetic outcome. The adapted surgical instrument can be an alternative to isolate the ligament under ultrasound guidance.