Cubital Tunnel Syndrome
What is cubital tunnel syndrome?
This tunnel is between two bony points - the medial epicondyle (on the inside of the elbow) and the olecranon (tip of the elbow). The ulnar nerve travels through this passageway. The ulnar nerve runs behind the elbow so the more the elbow bends, the more stretched the nerve becomes.
The ulnar nerve supplies
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Feeling to 1.5 fingers
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Muscle power to the small muscles of the hand that coordinate fine movements.
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Muscle power for ring and small finger flexion/bending.
What are the causes of cubital tunnel syndrome?
Direct pressure (compression) or stretching (traction) are the common reasons that the ulnar nerve is irritated.
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Leaning on the elbow (chronic compression).
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Sleeping with the elbow bent (chronic traction).
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Nerve subluxation (nerve slipping out of its groove) is present in ~15% people, making them more likely to have ulnar nerve symptoms.
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Sports/work involving repetitive elbow flexion (chronic traction).
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Fractures of the elbow or elbow arthritis may cause deformity which stretches the nerve or narrows the tunnel causing compression.
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Tumours, ganglion cysts or anatomical muscle variants (uncommon muscles that cross the nerve and compress it) are less common.
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Diabetes is a risk factor due to narrowing of blood vessels reducing blood supply to the nerve.
What are the signs & symptoms of cubital tunnel syndrome?
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Numbness and tingling of the small and ring finger
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Aching/tingling along the inner aspect of the forearm and elbow
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Loss of dexterity/clumsiness
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Wasting and weakness of the small muscles of the hand.
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Clawing of the ring and small finger.
How is cubital tunnel syndrome diagnosed?
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In most cases the diagnosis can be made by a thorough history of the symptoms and clinical examination.
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An ultrasound or MRI scan may be arranged to confirm the diagnosis if unclear.
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Nerve conduction tests are usually not positive until there is severe compression which is obvious to the specialist.
How is cubital tunnel syndrome treated?
Non-operative treatment
Studies show that ~90% of people with mild cubital tunnel syndrome will be able to stop the symptoms with these simple measures:
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Avoid resting on the elbow.
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Avoid sleeping with the elbow bent more than 90 degrees. Try using an extra pillow in the crook of your elbow to prevent flexion. Alternatively and elbow sleeve can be made to wear at night. (see below).
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Avoid prolonged or repeated elbow flexion. Instead of holding your phone to your ear for long periods, use ear pods or a headset; be aware of hobbies and sports that involve repeated flexion of the elbow.)
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Nerve gliding exercises - see image. Perform 10 repetitions once or twice a day. Referral to a hand therapist for instruction can be provided if you would prefer.
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A neoprene elbow sleeve– a soft, flexible sleeve made to fit your arm. It has a built-in pad that can be positioned over the nerve during the day and in front of the elbow at night to prevent the elbow bending.
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Steroid injection under ultrasound guidance. If the above options are not resolving you symptoms.
Cubital Tunnel Release Surgery
Cubital tunnel release surgery is usually recommended when symptoms are moderate to severe or if non-operative treatment has failed. The procedure is a day surgery under general anaesthetic. It is performed throught a 10-12cm incision at the back of your elbow.
The surgery is to relieve the nerve compression by opening the cubital tunnel that the nerve passes through (releasing) and moving (transposing) the nerve to the front of the elbow. A little fibrous tissue is used to create a barrier so the nerve cannot move back to behind the elbow.
The effects of the surgery are:
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The nerve is no longer in a tight tunnel so not compressed.
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The nerve is no longer in direct contact with hard surfaces when you lean on your elbow.
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The nerve is no longer being stretched each time the elbow is bent because it has been moved closer to the front of the elbow and has more redundancy.
What about the recovery from cubital tunnel surgery?
At surgery:
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The arm is immobilised in a bandage from the hand to above the elbow for 2 days only.
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There is a light fibreglass splint (half-cast) under the dressing that keeps the elbow bent at 90 degrees.
2 days:
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You will see the hand therapist who will remove the outer bandages and splint, replacing them with a light elasticised bandage.
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You will also be started on zn exercise program.
2 weeks:
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Each end of the dissolving stitch will be trimmed.
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The wound is now healed and can now be washed, and your exercises upgraded.
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Most people will drive from 2 weeks.
8 weeks:
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You will be reviewed by the surgeon to check your progress.
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You should be comfortable doing all your daily activities.
3-4 months:
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Depending on the severity of the nerve compression, it may take weeks to months for the nerve to recover.
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The swelling around the elbow takes 3-4 months to resolve.
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In severe cases complete recovery of feeling and strength may not be possible but usually there will be slow improvement up to 2 years and further deterioration will be prevented.
What are the risks of cubital tunnel surgery?
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Infection (1%)
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Ulnar nerve injury (1 in 1000) which could leave some permanent numbness or muscle weakness
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Small area of forearm numbness (2-3%) - small skin nerves cross the surgery site. All care it taken to protect these small branches but occasionally a minor nerve branch can be injured, leaving a small patch of numbness on the inner forearm.