Histological changes in the proximal suspensory ligament after neurectomy of the deep branch of the lateral palmar nerve of horses with induced proximal suspensory desmitis.
Authors: Lopez-Navarro Gabriela, Trigo-Tavera Francisco J, Rodriguez-Monterde Alejandro, Gutierrez-Ospina Gabriel, Arechavaleta-Velasco Miguel, Schumacher John, Schumacher James
Journal: Veterinary journal (London, England : 1997)
Summary
Proximal suspensory desmitis frequently causes persistent lameness in horses' forelimbs despite standard treatment protocols, and whilst deep branch lateral palmar nerve neurectomy has shown promise in resolving clinical signs, the structural consequences of denervation remain unclear. To investigate this gap, Lopez-Navarro and colleagues induced unilateral proximal suspensory ligament injury in eight horses using collagenase injection, performed neurectomy of the deep branch of the lateral palmar nerve, and subsequently examined the ligaments histologically and through lameness evaluation. All horses showed resolution of lameness following neurectomy, but microscopic examination revealed significant degenerative changes in the denervated ligaments: muscle fibres within the ligament underwent atrophy whilst simultaneously accumulating intramuscular fat and fibrous connective tissue infiltration. These structural alterations—reduced muscle integrity, decreased elasticity and compromised load-bearing capacity—suggest that neurectomy may create a mechanically weakened ligament structure, raising important concerns about re-injury risk and long-term soundness in horses managed this way. For practitioners considering neurectomy as a treatment option for refractory proximal suspensory desmitis, this study indicates the need for rigorous post-operative rehabilitation protocols and realistic client counselling regarding the structural limitations of denervated tissues, particularly regarding future athletic demands.
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Practical Takeaways
- •Neurectomy of the DBLPaN may resolve chronic thoracic limb lameness from PSD when conservative treatment fails, but carries risk of structural ligament weakening that could predispose to re-injury
- •Post-neurectomy denervation causes fat infiltration and atrophy of suspensory ligament muscle fibers, potentially compromising long-term biomechanical integrity
- •Carefully evaluate long-term soundness and exercise tolerance in horses undergoing this procedure, as the denervated ligament may be more prone to future injury
Key Findings
- •Neurectomy of the deep branch of the lateral palmar nerve resolved lameness in all 8 horses with induced proximal suspensory desmitis
- •Denervated suspensory ligament muscles showed atrophy with infiltration of fat and connective tissue
- •Histological changes in denervated ligaments reduced ligament strength and elasticity post-neurectomy