The ulnar nerve is the second major nerve supplying the hand. In its course to the forearm and hand, it passes through a tunnel on the inside of the elbow, where it is held tight and is vulnerable to pressure. This is the area commonly known as 'the funny bone'.
If the nerve is compressed in this tunnel or anywhere in this area, it may produce loss of sensation in part of the hand (especially the little and ring fingers) and some loss of the small, precise muscles in the hand.
Early symptoms include tingling in the little and ring fingers, especially when the elbow is bent or is leaned upon. Later symptoms may include clumsiness of the hand or wasting of the muscles in the hand.
Early cases can be treated with a splint which holds the elbow straight at night. Nevertheless, most patients will need investigation by nerve conduction study and will come to surgery.
Cubital tunnel surgery can be, and is usually, performed under regional anaesthesia - an injection of local anaesthetic in the neck or armpit, numbs the entire limb, while the patient is awake. This surgery is performed as an outpatient.
An incision is made on the inside of the elbow and the tunnel and various other points of compression are released, so as to relax all pressure on the nerve. Occasionally a small area of bone requires removal so as to stop the nerve angling around a sharp point.
Following cubital tunnel surgery, it will help recovery and will feel most comfortable, if the arm is elevated on cushions (such that the hand is above the heart) and the elbow is held straight.
The sutures are removed at two weeks after which the hand and arm can be used normally.
Because the compression of the nerve is at some distance from its target, the hand, it takes several weeks or months for the full effect of the decompression to develop. Symptoms usually improve quite rapidly after release but continue to improve for weeks or months.