Cubital tunnel syndrome arises when the ulnar nerve is compressed within the tunnel on the inner aspect of the elbow.
Overview
The ulnar nerve supplies sensation to part of the fourth finger and to the fifth finger, and provides the power of the small muscles of the hand.
Although most cases arise without an evident cause, the tunnel may also have been narrowed by arthritis of the elbow joint or by previous trauma.
Symptoms
The first symptoms are usually numbness or tingling in the fourth and fifth fingers. These are often intermittent at the outset and may become constant as the condition progresses.
The symptoms may be provoked by:
- leaning on the elbow;
- holding the elbow bent — while speaking on the telephone, for example;
- flexion of the elbow during sleep.
At more advanced stages the numbness becomes constant and the power of the hand diminishes. In severe cases there may be visible loss of muscle bulk in addition to loss of strength and dexterity.
Diagnosis
Radiographs of the elbow and nerve conduction studies may be used to establish the diagnosis.
Treatment
Wherever possible, the activities that provoke the symptoms should be avoided or the manner in which they are performed should be modified.
- using a headset when speaking on the telephone, so that the elbow need not be bent;
- wrapping the elbow or wearing a splint at night, to limit excessive flexion.
Such measures may be curative in early cases.
In severe cases, or where medical and supportive treatment has not produced a response, an operation is required to relieve the pressure on the nerve. Although surgery is usually undertaken to relieve the numbness, its principal purpose is to prevent progressive muscle weakness and wasting.
- Decompression
- The roof of the tunnel is simply divided, relieving the pressure on the nerve.
- Transposition
- The nerve is moved to a new position at the elbow.
Response to Treatment
The response to treatment depends on the degree of compression of the nerve. In almost all mild and moderate cases the symptoms can be resolved completely.
Surgery halts the progression of weakness; recovery of muscle power, however, is usually slow.