Femoral nerve neuropathy of an endurance horse as a sequela of iliopsoas muscle myopathy diagnosed by transrectal ultrasonography.

Research Overview

• This case report investigates a horse suffering from femoral nerve neuropathy caused by iliopsoas muscle myopathy using transrectal ultrasonography as a diagnostic tool.
• The study highlights the role of ultrasonography in diagnosing nerve compression injuries and monitoring recovery, resulting in the horse’s successful return to competition.

Background

• Femoral nerve neuropathy in horses leads to lameness, specifically affecting the ability to extend the stifle, which impairs lower limb function.
• The iliopsoas muscle, located near the femoral nerve, can develop myopathy (muscle disease or damage), which may compress the nerve.
• Compression of the femoral nerve by an injured iliopsoas muscle can cause significant functional impairment in athletic horses, especially endurance horses during competitions.

Case Description and Diagnostic Approach

• The subject is an endurance horse that developed lameness during competition, suspected to involve femoral nerve dysfunction.
• Traditional clinical examination suggested nerve involvement due to the stifle’s inability to fully extend, prompting further imaging diagnostics.
• Transrectal ultrasonography was employed to visualize the iliopsoas muscle and surrounding structures directly, which is a technique involving an ultrasound probe inserted rectally to obtain detailed images of internal structures.
• This imaging method enabled identification of the myopathy (injury and structural changes) in the iliopsoas muscle causing compression on the femoral nerve.

Importance of Transrectal Ultrasonography

• Transrectal ultrasonography provided a non-invasive, precise method to assess soft tissues and nerves in the deep pelvic region, which is typically difficult to examine.
• It allowed ongoing monitoring of the injury and healing progress over the recovery period, helping clinicians tailor treatment and rehabilitation.
• The imaging results complemented clinical signs to confirm the diagnosis of femoral nerve neuropathy secondary to muscle myopathy rather than other causes of lameness.

Treatment Outcome and Clinical Implications

• The horse underwent treatment and rehabilitation guided by clinical and ultrasonographic findings.
• One year post-injury, the horse achieved full recovery and returned to competition, demonstrating good functional restoration of the femoral nerve and iliopsoas muscle.
• The study underscores the value of including transrectal ultrasonography in cases of suspected femoral nerve involvement to improve diagnostic accuracy and management.
• It also suggests that early detection and monitoring using this imaging technique can contribute to better prognoses in horses with similar neuropathies.

Conclusion

• Femoral nerve neuropathy due to iliopsoas muscle myopathy can be effectively diagnosed with transrectal ultrasonography.
• This technique is recommended for evaluating nerve dysfunction where clinical signs suggest femoral nerve involvement.
• Successful recovery and return to athletic function are possible with proper diagnosis and management supported by imaging.