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?
Mild Symptoms
Most people 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.
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Avoid prolonged or repeated elbow flexion.
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Nerve gliding exercises - referral to a hand therapist or choose a physiotherapy instruction video on YouTube.
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An elbow sleeve– a soft, neoprene 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 may also help.
Moderate to Severe Symptoms
Surgery is usually recommended when symptoms are moderate to severe or if non-operative treatment has failed. The surgery is to relieve the nerve compression by opening (releasing) the nerve from the cubital tunnel and moving (transposing) the nerve to the front of the elbow, so it is no longer being stretched each time the elbow is bent. A little fibrous tissue is used to create a barrier so the nerve cannot move back to behind the elbow.
This is a day surgery performed under a general anaesthetic.
What about the recovery from cubital tunnel surgery?
At surgery: The arm is immobilised in a bandage from the hand to above the elbow for 2 days only. There is a light fibreglass splint (half-cast) under the dressing that keeps the elbow bent at 90 degrees.
2 days: You will see the hand therapist who will remove the outer bandages and splint, replacing them with a light elasticised bandage. You will also be given an exercise program.
2 weeks: Each end of the dissolving stitch will be trimmed; the wound can now be washed, and your exercises upgraded. Most people will drive from 2 weeks.
8 weeks: You will be reviewed by the surgeon to check your progress. You should be comfortable doing all your daily activities.
3-4 months: Depending on the severity of the nerve compression, it may take weeks to months for the nerve to recover. The swelling around the elbow may take 3-4 months to fully settle. In severe cases complete recovery of feeling and strength may not be possible.
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.