Cubital tunnel syndrome

What it is

The ulnar nerve is one of the major nerves supplying the arm and hand. It begins from nerves leaving the spinal cord in the neck, passes through the neck and beneath the collarbone, then travels down the inner side of the arm. At the elbow it passes through a relatively confined space behind the medial epicondyle — the bony prominence on the inside of the elbow — before continuing into the forearm and hand. This is the nerve you may recognise from hitting your “funny bone.”

How it usually presents

• Pins and needles or numbness in the little and ring fingers, although symptoms do not follow an identical pattern in everyone
• Waking during the night with an uncomfortable numb or tingling hand, as keeping the elbow deeply bent makes symptoms worse
• Pain on the inside of the elbow
• Reduced grip strength, clumsiness with fine tasks or loss of dexterity

Why does it happen?

The area behind the elbow is one of the commonest places for the ulnar nerve to become irritated or compressed. The nerve may become tight as the elbow bends, or can be compressed by surrounding fascia and other soft tissues. If compression becomes more significant or prolonged, the muscles supplied by the nerve can also become affected, so you may notice reduced grip strength, difficulty with fine movements or loss of dexterity in the hand.

How it is assessed

Examination of nerve function in the hand, usually supported by nerve conduction studies, often combined with EMG. These use electrical stimulation to assess how effectively the nerve is transmitting signals and can help identify where compression is occurring. They are useful but not 100% accurate, and are therefore interpreted alongside your symptoms and examination rather than relied upon alone.

Do I need a scan or surgery?

Treatment can initially be very simple. If symptoms persist, or there is evidence that the nerve is beginning to affect the muscles of the hand, surgery may be appropriate. A cubital tunnel release allows the nerve to move freely, and if the nerve remains stable behind the elbow this may be all that is required. Occasionally the nerve itself is unstable, in which case it may need to be moved to a more stable position in front of the elbow — an anterior transposition, which is a slightly more involved procedure.

Treatment options

• Avoiding prolonged deep elbow flexion, particularly whilst sleeping
• A night splint to reduce irritation of the nerve
• Cubital tunnel release, a relatively small operation which releases the structures constricting the nerve
• Anterior transposition of the ulnar nerve in selected patients, where the nerve moves or “flicks” around the inside of the elbow

Non-surgical treatment is considered first wherever it is reasonable. Which option suits you depends on your symptoms, your goals and what you want from treatment, which is exactly what we discuss in clinic.