Joseph Yao

Cubital Tunnel Syndrome

Cubital tunnel syndrome (CTS) refers to irritation or injury of the ulnar nerve as it courses through a tunnel called the cubital tunnel on the inside of the elbow. The ulnar nerve in this location is informally termed the "funny bone," and bumping it results in an electrical sensation shooting down to the small and ring fingers. The ulnar nerve provides feeling to the small finger and the side of the ring finger that faces the small finger. It also supplies many of the muscles of the hand.
            The ulnar nerve may be injured by external pressure applied to the nerve. Pressure may occur from truck drivers resting the inside of the elbow against an armrest in their cab. The ulnar nerve may sustain stretch injury when the elbow is held bent for long periods of time, such as holding a telephone to one's ear.
            Ulnar nerve irritation may present with pain, numbness or tingling involving the small finger side of the palm and small finger and the side of the ring finger facing the small fingers. More serious ulnar nerve compression may be associated with hand grip weakness. Some of the muscles may shrink in size (atrophy) due to nerve injury. The most noticeable muscle atrophy involves the small finger side of the palm and the muscle that is located on the side of the index finger's base.
            Some simple physical exam tests can be done to help determine if a person has CTS. Tinel's sign is performed by tapping a fingertip over the cubital tunnel. The cubital tunnel compression test consists of placing finger pressure over the cubital tunnel. The elbow flexion test consists of holding the elbow bent. These tests are considered positive for CTS if they cause pain and numbness radiating into the small finger and the side of the ring finger facing the small finger.
            Other tests to confirm the diagnosis of CTS include injecting steroid and a local anesthetic into the cubital tunnel. Symptom relief after a cubital tunnel steroid injection supports a diagnosis of cubital tunnel syndrome. Nerve conduction tests can help make the diagnosis.
            Treatment for CTS includes avoiding pressure to the inside of the elbow and not holding the elbow bent for very long. Splints can be worn in bed to prevent the elbow from being held in a bent position during sleep. Cubital tunnel steroid injections may be helpful. Surgery includes taking the ulnar nerve out of the cubital tunnel and moving it to the front of the inner side of the elbow. Surgery takes pressure off of the nerve and prevents the nerve from being stretched when the elbow is bent. A splint holds the elbow in a bent position for three weeks, and the elbow should not be used forcefully for for six weeks.
            Dr. Joseph Yao has undertaken extensive subspecialty training in joint re- placement after completing an orthopedic surgery residency. He has been in private practice orthopedic surgery since 1987, and he has treated many truck drivers for joint and nerve ailments.