Cubital Tunnel Syndrome
The ulnar nerve originates from the medial cord of the brachial plexus. The nerve runs down the arm where it passes under the medial epicondyle of the humerus. The ulnar nerve can become pinched in different locations.
Causes of ulnar nerve entrapment around the cubital tunnel
1. Thoracic outlet syndrome
2. Cubital tunnel syndrome
3. Ulnar tunnel syndrome
4. Cubitus Valgus- is a deformity in which the elbow is turned outward.
5. Entrapment may also occur due to a spur on the medial epicondyle.
The symptoms of cubital tunnel syndrome are worsened by performing activities that require bending at the elbow. Keeping the elbow extended, especially at night, will relieve the pressure being placed on the ulnar nerve at the elbow.
As the ulnar nerve enters the anterior compartment, it gives the innervation to the flexor carpi ulnaris and the medial half of the flexor digitorum profundus. Distally, the ulnar nerve supplies several muscles of the hand.
As the ulnar nerve passes behind the elbow, it may become compressed or irritated. The most frequent site of compression with cubital tunnel is at the two heads of the flexor carpi ulnaris (FCU) muscle. The ulnar nerve tracels through a tunnel of tissue (cubital tunnel) that runs under the medial epicondyle. Pressure on the nerve at the elbow can cause numbness or pain in the elbow, hand, wrist, or fingers.
A patient with cubital tunnel syndrome will describe symptoms of pain and numbness in the elbow as well as tingling in the ring and little fingers. More severe symptoms of cubital tunnel syndrome include:
· Weak or clumsy hand
· Weakness affecting the ring and little fingers
· Muscle wasting
· Claw hand deformity if compression below the elbow
Differential Diagnosis include:
· An injury of the cervical spine at the C8 nerve root
· Thoracic oulet syndrome- Entrapment at the area between the rib cage and collar bone
· Pancoast tumor- Apical lung tumor
During the clinical examination, you will look for the Tinel’s Sign at the elbow. The tapping technique is performed to test for symptoms of ulnar nerve entrapment at the cubital tunnel. Other tests include the elbow flexion test and Froment’s sign.
Conservative treatment methods include NSAIDs, a night splint, elbow pads, therapy, and injections. If surgery is necessary, the surgeon will perform a release with or without transposition. The type of transposition is controversial.
There is a bad prognosis if there is intrinsic muscle atrophy. A complication of surgery is an injury to the medial antebrachial cutaneous nerve. Neurolysis is not helpful.