Incomplete anterior interosseous nerve palsy following spinal surgery. A report of two cases

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.

A simple clinical test to differentiate rupture of flexor pollicis longus and incomplete anterior interosseous paralysis

Incomplete anterior interosseous nerve paralysis and spontaneous rupture of flexor pollicis longus tendon are conditions which mimic each other closely and have been mistaken for each other, leading to unnecessary surgery. This is a report of a simple and reliable clinical test to differentiate between the two conditions. A search of the literature has not revealed a previous description of this test.

AAEM case report #25: anterior interosseous nerve syndrome

A case study is reported regarding a 57-year-old woman, chose chief complaint was weakness in her thumb that she had noted while gardening. The patient described difficulty pulling weeds out because of an inability to get a firm grip when using the thumb. Physical examination showed weakness of the flexor pollicis longus and flexor digitorum profundus to the index finger. There was no other weakness and no clinical sensory deficit. Electrodiagnostic studies revealed normal median motor and sensory nerve conduction studies with needle examination abnormalities noted only in the flexor pollicis longus, flexor digitorum profundus, and pronator quadratus. The literature on anterior interosseous nerve syndrome (AINS) is reviewed. It is important to differentiate those with idiopathic AINS as part of a neuralgic amyotrophy picture from those with an anatomic cause such as a fibrous band or anomalous muscle. Electrodiagnostic examination can be useful to help make this distinction.