Selective anterior interosseous nerve conduction study: Coaxial needle versus surface electrode recordings

Anterior Interosseous Nerve Syndrome

Anterior interosseous nerve syndrome (AINS) is a rare form of peripheral neuropathy which involves disruption of the anterior interosseous nerve. The pathophysiology of AINS remains unclear. AINS typically initially presents with forearm pain and may gradually progress to palsy of the deep muscles of the anterior forearm. Diagnosis of AINS requires thorough patient history and physical exam. EMG is the preferred diagnostic study and classically reveals abnormal activity and prolonged latency periods within the evoked action potentials of the FPL and PQ. Due to the self-limiting nature of AINS, there is general agreement that conservative and symptomatic management should be explored for up to 6 months as first line therapy, which usually includes analgesics and nonsteroidal anti-inflammatory drugs, contracture prevention, hand therapy, and hand splinting. Surgical options such as internal neurolysis and minimally invasive endoscopic decompression may be explored if functional recovery from conservative management is limited.

Isolated Nerve Palsy of the Flexor Pollicis Longus After a Radial Shaft Fracture: A Case Report

We present the case of a patient who developed an isolated palsy of the flexor pollicis longus (FPL) branch of the anterior interosseous nerve (AIN) following a fracture of the right radial shaft. The diagnosis of AIN palsy in this setting is rare, especially involving partial neuropathies of only the FPL branch. Clinical presentation in this scenario can be mistaken for other musculoskeletal pathology, and electrodiagnostic studies can be helpful in confirming the diagnosis.

[Lesions of the anterior interosseous nerve: differentiating between compression neuropathy and neuritis]

BACKGROUND

In cases of anterior interosseous nerve (AIN) syndrome, it is often difficult to differentiate between compression neuropathy and neuritis.

MATERIAL AND METHODS

This review analyses the clinical aspects of the neuritic AIN syndrome and the different diagnostic tools for securing the diagnosis and differentiating the condition from compression neuropathy. Based on these data, the current therapeutic options are proposed.

RESULTS

The AIN syndrome often results from neuritis of the AIN fascicles within the trunk of the median nerve. The differentiation between neuritis and compression neuropathy of the AIN is based on dedicated neurophysiological examinations as well as nerve sonography and MRI neurography. Although conservative treatment is the gold standard, microsurgical interventions have become more important in recent years.

CONCLUSION

A dedicated diagnostic workup of the AIN syndrome is paramount for optimal treatment. Conservative treatment remains the standard to date. However, if torsions and constrictions of nerve fascicles are detected, intrafascicular neurolysis should be considered, as current research shows the potential for an improved outcome in such cases.