Cubital Tunnel Syndrome
One cause of persisting tingling and numbness in the little finger and ring finger is compression of the ulnar nerve at the elbow, where it runs behind the inner side of the humerus (funny bone), in the cubital tunnel. There are many conditions that damage the nerve in that area: blunt trauma, thickened muscle or fibrous bands etc, but one of the most common is sleeping posture. People can sleep with their elbows heavily bent: or arms above the head: and in both those positions the ulnar nerve is stretched, and squashed reducing blood flow and causing nerve conduction block: felt as numbness and tingling or pins and needles in the fingers.
When compression becomes severe, weakness can develop: and because this nerve supplies many of the muscles controlling fine, delicate finger and hand function that weakness can be very disabling.
An accurate examination and history is needed. Testing of sensory function and the tesing of individual muscle strength is important, together with examining the nerve itself at the elbow and wrist.
An ultrasound examination by an experienced radiologist can be very helpful.
Nerve conduction studies: an electrical function test can be very helpful.
In the early phases of this condition treatment with therapy interventions can be very successful. You can commonly identify elbow positions that make your symptoms worse: resting your head on your hand while reading: sleeping curled up like a baby- or with your arms flung up above your head: driving postures: or computer operating/ gaming positions: can all squeeze the nerve, and need to be avoided.
Sometimes protection in a splint is needed to avoid odd sleeping postures.
We generally try therapy manoeuvres for 3 to 6 months depending on symptom response.
There have been many surgical operations designed to treat this condition: and I have tried most of them. It is hard to identify for each individual the point of compression: and the factors in how they use their arm to allow the surgery to release the nerve and protect it from further injury.
At this time I can generally advise which of 2 operations seems best suited to you.
Some people need a simple release of surrounding compressive tissues: that I often perform with endoscope assistance to limit the scar length, as the nerve needs clear release over about 16cm in most people.
Some people get better results if the prominence of the bone is removed (medial epicondylectomy) as well as complete release of the nerve, that allows the ulnar nerve to move forwards when the elbow bends (anterior transposition), and so relaxes it more. Although this surgery is more involved, the need for reoperation because of further compression from scar developing during the healing phase is uncommon: less than 2%.
A bandage is applied to limit elbow motion for the first week: but I ask that you do bend and straighten within the bandage limits. After that free exercise to regain full elbow bend and straightness is helped with therapist assistance. Twisting is only exercised after 4 weeks of healing. We want the nerve to move: not get caught in scar again.
- Philip A. Griffin, FRACS