Intrathecal enalapril reduces adhesion formation in experimentally induced digital flexor tendon sheath injuries in horses

• Published in: Veterinary surgery 2024-11
• Main Authors: Willette, Jaclyn A, Tsoi, Mayra, Frobish, Daniel, VanderBroek, Ashley R
• Format: Article
• Language: English
• ISSN: 0161-3499; 1532-950X; 1532-950X
• DOI: 10.1111/vsu.14186

The objectives of the study were to describe a standing percutaneous adhesion induction model in the digital flexor tendon sheath (DFTS) of horses and to evaluate the effect of intrathecal administration of the angiotensin-converting enzyme (ACE) inhibitor enalapril on tendon healing and adhesion formation. Randomized, blinded, controlled experimental study. Eight healthy horses. A collagenase-induced adhesion model was implemented in the deep digital flexor tendon (DDFT) of both forelimbs under standing ultrasonographic guidance. Daily intrathecal injections of 5 mg enalapril (the treatment condition) were administered to a randomly assigned forelimb for 5 days, with the contralateral limb receiving an equivalent volume of 0.9% NaCl (the control). Lameness and limb circumference were recorded weekly. Horses were euthanized after 8 weeks and evaluated for gross digital flexor tendon sheath (DFTS) adhesions. Tendons were collected for histopathologic scoring of DDFT healing. Paired data were analyzed using a one-sided alternative sign test and longitudinal regression. Multiple DFTS adhesions were formed in control limbs of all horses. The median number of gross DFTS adhesions in treated limbs was less than in control limbs (p = .0039). The average reduction in limb circumference and lameness scores over time occurred faster in treated versus control limbs (p