Cubital Tunnel Syndrome

The ulnar nerve is one of the main nerves. It is responsible for the flexing of the fingers in the basal joints and the extension of the fingers at their middle and end joints. It is also responsible for the spreading of the fingers and the movement of the thumb towards the fingers (adduction). All of these functions are essential in enabling the hand to perform a grip function without obstruction. The ulnar nerve also delivers sensation to the fifth finger and to the little-finger side of the fourth finger as well as to the ulnar side of the hand.

On its course from the shoulder to the hand, the ulnar nerve encounters three predilection points where it is particularly susceptible to damage due to the narrow structures around it. If this occurs, it is known as cubital tunnel syndrome.

The first point lies above the elbow. Here the nerve passes through a connective band of tissue known as Struther’s Arcade. Thickening of this band can cause compression damage to the nerve. The second point is the most well-known. Practically everyone must have once experienced the painful results of hitting their funny bone. This is because this area of the elbow is rather exposed and it is where the ulnar nerve passes along a groove on the bone on the inside of the upper-arm. However, this nerve is most commonly pinched at the point of entry to the forearm muscles.

The causes often remain unclear. Occasionally after a joint fracture there are induced symptoms caused by the break, which can be identified on an x-ray of the elbow. But cubital tunnel syndrome can possibly also be caused by ganglions, calcium accumulation, rheumatic disorders, tumours, incorrect postural position during lengthy surgery or as a result of being confined to bed.

Clinically, there is reason to suspect cubital tunnel syndrome when there is abnormal sensations, tingling or numbness in the areas fed by the ulnar nerve (see above). In more progressive stages of nerve compression damage, the nerve’s motoric functions will be impaired. Patients will only be able to form a pinch or fist with reduced strength or not be able to form them at all. The latter stage is the forming of a claw hand. This occurs because the nerve’s counteracting function has been lost, resulting in an overextension in the basal joints, and the middle and end finger joints being held in flexion. In these cases muscle atrophy can be seen between the thumb and index finger.

The diagnosis of cubital tunnel syndrome is confirmed through electroneurographic tests, which also assess the nerve’s condition or the extent of damage. Further electromyography testing is required to establish the exact location of the damage.

If the disease has already progressed to an advanced stage, or initial treatment methods (neural therapy, medicine, orthopaedic bandages/splints etc.), have been unsuccessful in relieving pain or achieving any significant improvement, there is a choice of two operative interventions.The first is an open operation. This involves exposing the nerve by way of an adequately sized incision on the inside of the elbow. During the operation, the behaviour of the nerve while mobilising the joint can be adequately assessed. If, when flexed, the nerve glides out of its anatomical path, then it may have to be repositioned on the inside of the elbow. The period of aftercare can be considerably reduced through endoscopic surgery. This involves using so-called keyhole surgery. Here a minute incision is made through which the joint and path of the nerve can be fully observed and decompressed along its length.

After surgery, the pain usually disappears immediately, but in more developed cases, the return of sensation and complete mobility may take a while or occasionally not return at all. If the condition has existed for a great length of time, a complete recovery is not likely to be expected. As a rule, the earlier the operation is made during the course of the disorder’s development, the greater the chances of diminishing the symptoms.

Cubital tunnel syndrome is a nerve compression syndrome.
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