Neurolysis is not required for young patients with a spontaneous palsy of the anterior interosseous nerve

M. Seki, H. Nakamura, H. Kono
2006 Journal of Bone and Joint Surgery  
We studied 21 patients with a spontaneous palsy of the anterior interosseous nerve. There were 11 men and 10 women with a mean age at onset of 39 years (17 to 65). Pain around the elbow or another region (forearm, shoulder, upper arm, systemic arthralgia) was present in 17 patients and typically lasted for two to three weeks. It had settled within six weeks in every case. In ten cases the palsy developed as the pain settled. A complete palsy of flexor pollicis longus and flexor digitorum
more » ... or digitorum profundus to the index finger was seen in 13 cases and an isolated palsy of flexor pollicis longus in five. All patients were treated without operation. The mean time to initial muscle contraction was nine months (2 to 18) in palsy of the flexor digitorum profundus to the index finger, and ten months (1 to 24) for a complete palsy of flexor pollicis longus. An improvement in muscle strength to British Medical Research Council grade 4 or better was seen in all 15 patients with a complete palsy of the flexor digitorum profundus and in 16 of 18 with a complete palsy of flexor pollicis longus. There was no significant correlation between the duration of pain and either the time to initial muscle contraction or final muscle strength. Prolonged pain was not always associated with a poor outcome but the age of the patient when the palsy developed was strongly correlated. Recovery occurred within 12 months in patients under the age of 40 years who achieved a final British Medical Research Council grade of 4 or better. Surgical decompression does not appear to be indicated for young patients with this condition. Spontaneous atraumatic palsy of the anterior interosseous nerve has been described in association with neuralgic amytrophy, 1,2 isolated neuritis, 3 entrapment neuropathy 4,5 and hourglass-like fascicular constriction. 6 The aetiology of the condition, however, remains uncertain. Neurolysis of the nerve has been recommended if conservative treatment has not been successful after 12 weeks. 7-9 Seror 10 concluded that surgery should not be considered for a year, as late spontaneous recovery can occur. There have also been reports that suggest no difference in outcome between surgical and conservative treatment. 11,12 Nagano 6 identified an hourglass-like fascicular constriction of the relevant portion of the median nerve above the elbow: neurolysis yielded good results in such cases. No consensus has been reached about the treatment of this palsy because its aetiology is uncertain. Neither the time to spontaneous recovery, nor the extent to which the nerve will recover if left untreated have been defined. The purpose of this study was to determine the time to spontaneous recovery and the factors which affect it. Patients and Methods We studied 21 patients (11 men and 10 women) with a spontaneous palsy of the anterior interosseous nerve who attended the
doi:10.1302/0301-620x.88b12.17700 pmid:17159172 fatcat:mh4si5okyrdpdaq3fylyyc7j2a