[Nocturnal orthosis: a new treatment of compression of the ulnar nerve at the elbow. 30 cases].

Compression of the ulnar nerve at the elbow was confirmed by electromyography in 30 patients including 29 cases of idiopathic aetiology and 1 case of late onset ulnar palsy. Six cases occurred after general anaesthesia and 3 had undergone an unsuccessful operation. All patients were managed solely with an orthesis worn at night. The orthesis held the elbow in 60 degrees flexion. Clinical improvement was noted in all cases (including the 3 cases of unsuccessful surgery) evaluated by the patient and the physician at 88% on the average. Improvement occurred rapidly and was evaluated at 50% on day 15 in 9 out of 10 patients seen on this day. The level of improvement was directly related to regular use of the orthesis. Seven electromyographic criteria were measured and nerve conduction speed was 33.0 m/sec (motor and sensory) and improved significantly by 7.3 m/sec (motor) and 9.5 m/sec (sensory) in all cases but one (p < 10(-8)). In conclusion, this simple non-invasive management protocol is not a simple symptomatic treatment but helps restore nerve function. The effectiveness of this method suggests that nocturnal position plays a major role in impairment due to compression of the ulnar nerve.