How to perform a venogram of the equine foot

Objective: The objective of this video is to demonstrate a reliable technique for obtaining diagnostic venogram images of the equine foot. Venogram studies are indicated to assess vascular contrast filling of the equine digit, primarily in cases of laminitis. Animals: A healthy university-owned horse was used for demonstration purposes. The protocol was approved by the Virginia Polytechnic Institute and State University IACUC. Methods: The horse's shoes are removed, and the foot is cleaned of debris. The horse is sedated and a medial and lateral abaxial nerve block performed. The pastern is clipped if the hair coat is long. An aseptic scrub is performed on the pastern, and the horse is placed on radiographic positioning blocks. An Esmarch tourniquet is placed at the fetlock, and a 21-gauge butterfly catheter is inserted into the palmar digital vein. Iodinated contrast is injected; immediately following contrast injection, radiographic views are obtained. Weight-bearing lateral-medial, weight-bearing dorsal-palmar, upright pedal/dorsoproximal-palmarodistal oblique, unloaded lateral-medial, unloaded dorsopalmar, and late weight-bearing lateral-medial and dorsopalmar images are our standard views. The tourniquet is removed, followed by removal of the butterfly catheter and a light bandage placed over the venipuncture site. Results: Radiographic images are obtained and reviewed by clinicians to determine whether there is decreased or abnormal vascular contrast filling of the foot. Clinical Relevance: Findings from the venogram study can guide shoeing and other treatment choices, particularly for laminitic horses.