From the Research
Interosseous nerve syndrome is a compression neuropathy that affects the anterior interosseous nerve (AIN) or posterior interosseous nerve (PIN) in the forearm, leading to muscle weakness and potentially permanent damage if left untreated. The syndrome can be caused by trauma, space-occupying lesions, or compression from surrounding anatomical structures like the Pronator Teres muscle 1. The anterior variant of the syndrome causes weakness in the thumb and index finger pinch, affecting the flexor pollicis longus and flexor digitorum profundus muscles, while the posterior variant leads to weakness in finger and wrist extension 2.
Diagnosis and Treatment
Diagnosis involves physical examination, electromyography, and nerve conduction studies 3. Treatment begins with conservative measures including rest, anti-inflammatory medications like ibuprofen (400-800mg three times daily), and physical therapy. If symptoms persist beyond 8-12 weeks, surgical decompression may be necessary to release the nerve from compression points 1, 2. Recovery can take several months as nerves heal slowly at approximately 1mm per day. Early diagnosis and treatment improve outcomes, as prolonged compression can lead to permanent muscle weakness and atrophy.
Key Considerations
- The exact etiology and pathophysiology of the disorder remain unclear, but it is increasingly thought to be an inflammatory condition of the nerve rather than a compressive neuropathy 4.
- Peripheral neuropathy can be one of the first symptoms of systemic vasculitis, which needs early systemic immunotherapy to prevent extensive nerve damage 4.
- A thorough physical examination is paramount to localize compressed segments of the nerves, and electrodiagnostic and imaging studies may aid in diagnosis 3.
Recommendations
- Conservative treatment should be started for every patient, and if no signs of recovery appear within 3 months, operative exploration should be performed 1.
- Surgical intervention is recommended in confirmed interosseous nerve syndrome from compression neuropathy, refractive to conservative therapy 2.