Prognosis and prognostic factors in non-traumatic acute-onset compressive mononeuropathies--radial and peroneal mononeuropathies.

Background And Purpose: Little is known about the natural history of non-traumatic compressive mononeuropathies. To improve patient management, prognostic factors and outcome in patients with non-traumatic peroneal and radial mononeuropathies were studied.

Methods: Retrospective clinical, electrophysiological and sonographic data of patients with non-traumatic peroneal and radial mononeuropathies were evaluated. Clinical, electrophysiological and sonographic evaluations had to take place 2-12 weeks after symptom onset and follow-up had to be for >6 months.

Results: Twenty-five patients with peroneal mononeuropathy and 58 with radial mononeuropathy were included. Mean follow-up was 8.9 ± 2.4 months. Approximately 90% of patients recovered to a muscle strength of British Medical Research Council grade 4 or 5. Multiple logistic regression analysis revealed conduction block on nerve conduction studies, younger age and less severe initial weakness as indicators for a good prognosis. Peripheral nerve ultrasound was not prognostic in the 40 patients where it was available.

Conclusions: The present study shows a good prognosis for spontaneous recovery after non-traumatic acute-onset compressive peroneal and radial mononeuropathies. Patients with denervation on needle electromyography, older age and severe initial weakness have a poorer prognosis and should be closely monitored to facilitate timely surgery whenever weakness persists. Peripheral nerve ultrasound seems to be of limited prognostic value in these mononeuropathies.