Cubital Tunnel Syndrome
What is Cubital Tunnel Syndrome?
The cubital tunnel is a fibrous passageway along the inner side of the elbow that contains the ulnar nerve, which is one of three major nerves of the forearm and hand. It is responsible for sensation to the pinky finger and pinky side of the ring finger. The ulnar nerve also controls the small muscles of the hand, allowing the fingers to spread and straighten at their last joints and the thumb to key pinch. In Cubital Tunnel Syndrome, the fibrous passageway for the ulnar nerve can become narrower along the inner side of the elbow and lead to compression of the nerve.
Symptoms of Cubital Tunnel Syndrome
With continued compression of the ulnar nerve, patients can develop numbness and tingling of the pinky finger and pinky side of the ring finger. In long-standing or severe circumstances, ulnar nerve compression can lead to weakness of thumb key pinch and finger straightening and loss of muscle mass between the bones of the back of the hand. Sometimes patient interpret this weakness as clumsiness. Symptoms may worsen when the elbow if bent, as this position places the ulnar nerve on more stretch and pressure. Some patients awake in the morning with numbness of the pinky finger and/or pinky side of the ring finger.
Causes of Cubital Tunnel Syndrome
Risk factors for Cubital Tunnel Syndrome include holding the elbow constantly in a position, obesity, diabetes, and trauma to the inner side of the elbow. The common factor in these conditions is that they all lead to increased swelling in the fibrous passageway and decreased space for the ulnar nerve. In this situation, the nerve remains in continuity but is its outer lining and blood supply can be damaged by the pressure caused by this tight passageway. In response, scar tissue replaces the natural outer insulation of the nerve, called myelin. Myelin is critical in speeding the transmission of electrical signals to the muscle to cause contractions or from the skin to the brain to produce feeling. With scar replacing myelin, electrical signals cannot easily travel across the nerve
Diagnosing Cubital Tunnel Syndrome
Cubital Tunnel Syndrome can generally be diagnosed by the history of symptoms and by physical exam looking for signs of pinky finger or pinky side of the ring finger numbness, loss of muscle mass in the back of the hand, or nerve inflammation (elbow flexion, Tinel’s, and scratch collapse tests). In the elbow flexion test, the elbow is maximally bent and the wrist held straight for up to 60 seconds and the patient is asked if there are any symptoms of pinky finger or pinky side of the ring finger numbness, tingling, or pain. Using the Tinel’s test, the skin over the cubital tunnel is tapped and the patient is asked if there are any signs of tingling or electrical shocks traveling to the pinky finger or pinky side of the ring finger. For the scratch-collapse test, the patient performs resisted shoulder external rotation exercises. The test is considered positive if the affected inner elbow is lightly scratched and the patient momentarily collapses while performing resisted shoulder external rotation. In situations where the diagnosis is unclear, a nerve conduction and muscle study can be ordered to obtain more information on the health of the ulnar nerve and its muscles. In situations where the diagnosis is unclear, a nerve conduction and muscle study can be ordered to obtain more information on the health of the ulnar nerve and its muscles.
Cubital Tunnel Syndrome Treatment Options
Treatment of Cubital Tunnel Syndrome begins with elbow splinting in the straight position, non-steroidal anti-inflammatory drugs to reduce the swelling and inflammation, diet and exercise in obese patients, and strict glucose control in diabetics. If these measures fail to eliminate the patient’s persistent pain, numbness, and/or muscle weakness, a cubital tunnel release is recommended. In this procedure, a nerve decompression / neurolysis is performed of the ulnar nerve through a small incision along the inner side of the elbow. The goal is to provide space for the nerve and its blood supply, giving it a chance to regenerate. Doing so in a timely fashion should lead to speedier electrical signals and return of movement, feeling, and function.
Recovery From Cubital Tunnel Syndrome Surgery
Cubital tunnel release generally takes less than one-hour and can be performed under general or wide awake local anesthesia. After the completion of surgery, the elbow is wrapped in a soft, bulky dressing. Following a 1-2-hour recovery period, patients are discharged home the same day on Tylenol, Motrin, and sometimes on a short course of narcotics. One week after surgery, patients may take off their bandages and get the incision wet. Active range of motion exercises about the elbow are also started at that time. Lifting is limited to 5 pounds for 6 weeks. Six weeks after surgery, patients may resume full activity. With mild and/or intermittent symptoms, relief of numbness, tingling, and pain is often immediate. With long-standing or severe cases, relief of symptoms and return of muscle function may be more gradual and over the course of many months.