Cubital tunnel syndrome is a condition that affects the ulnar nerve where it crosses the inside edge of the elbow. The symptoms are very similar to the pain that comes from hitting your funny bone. The ulnar nerve passes through the cubital tunnel just behind the medial epicondyle, which is the bony prominance on the medial side of the elbow. It supplies feeling to the little finger and half the ring finger and innervates the small intrinsic) muscles of the hand.
Cubital tunnel syndrome has several possible causes, but most of the time it is caused by strain which accompanies elbow flexion. The ulnar nerve actually stretches several millimeters when the elbow is bent. When a nerve experiences 6-8% strain it will start to have its circulation impaired. This ultimately leads to changes in the nerve, beginning with demyelination—thinning of its insulation, and ending up with atrophy of the muscles it supplies along with numbness. Sometimes the nerve will even bluxate over the bony medial epicondyle as the elbow is flexed. Over time, this too can cause irritation.
Numbness on the inside of the hand and in the ring and little fingers is an early sign of cubital tunnel syndrome. The numbness may develop into pain or an ache either at the elbow or on the outside of the hand. The numbness is often felt when the elbow is bent for long periods, such as when talking on the phone or while sleeping. The hand and thumb may also become clumsy as the muscles become affected. Tapping or bumping the nerve in the cubital tunnel will cause an electric shock sensation down to the little finger. This is called Tinel's sign.
When you are first evaluated I will probably order a Nerve Conduction test in order to assess the conduction velocity of the nerve and to check for evidence of muscle fibrillation—a finding that accompanies more advanced nerve injury. The early symptoms of cubital tunnel syndrome usually lessen if you just stop whatever is causing the symptoms. Anti-inflammatory medications may help control the symptoms, but it is much more important to stop doing whatever is causing the pain in the first place. Limit the amount of time you do tasks that require a lot of bending in the elbow. Take frequent breaks, and don’t lean on the inside of your elbow. A mainstay of conservative treatment includes sleeping with your elbow extended, either deliberately or by placing your arm in a splint at night. You can also wear the elbow pad during the day to protect the nerve from the direct pressure of leaning.
Surgical Treatment Options
Your symptoms may not go away, even with changes in your activities and conservative medical treatment. If symptoms persist for 3-6 months, I will often discuss surgical intervention because if symptoms are simply ignored, the problem may very well worsen, and, most importantly, the results of surgery decline as the damage to the ulnar nerve worsens.
The goal of surgery is to release the pressure on the ulnar nerve where it passes through the cubital tunnel. There are 3 common alternatives that I recommend: in situ release, in situ release with medial epicondylectomy, and in situ release with anterior subcutaneous transposition. The surgical literature does not clearly show that one operation is better than the other. More recent trends have favored in situ release alone, but this option may have a higher failure rate(see the article on Revision Surgery for Cubital Tunnel Syndrome).
If the nerve subluxates either before, or after in situ release, medial epiconylectomy or anterior transposition are options.
In my experience since 1994, proper indications for surgery and expert surgical technique result in patient satisfaction in more than 90% of cases. In roughly 25% of cases, however, symptoms do not improve as much as one would hope for, and the tinel’s sign may never go away.
Surgery can be performed using a a regional anesthetic. After surgery you'll have a soft bandage wrapped from your hand to your armpit, and at 6-7 days after surgery the dressing will be removed and you will work on range of motion. You just need to be careful to avoid doing too much, too quickly. At about 6-8 weeks, you'll start doing more active strengthening. It may take 3 or so months to feel better, and full recovery of the nerve may take 6-12 months.
