Cubital Tunnel Syndrome
What is Cubital Tunnel Syndrome?
Cubital Tunnel Syndrome is a constellation of symptoms resulting from entrapment, pressure, or irritation of the ulnar nerve at the elbow.The ulnar nerve runs the full length of the arm as it passes from the neck to the hand.Its sensory functions include sensation in the pinky finger and one half of the ring finger.It also gives motor control to many of the small muscles of the hand responsible for dexterity and some of the larger muscles of the forearm responsible for grip strength.
The cubital tunnel is an anatomic space formed by the humerus, the medial collateral ligament, and its retinaculum.The tunnel is located behind the bony protuberance of the medial epicondyle.As the ulnar nerve passes through this cubital tunnel it is extremely close to the skin’s surface, and prone to trauma.As a reference, this area is known as the “funny bone”, and a blow to the ulnar nerve here produces a painful, shock-like jolt.
What causes Cubital Tunnel Syndrome?
Cubital Tunnel Syndrome is a result of entrapment, pressure, or irritation of the ulnar nerve at the elbow.Simply bending the elbow causes stretching of the ulnar nerve and also narrows the diameter of the cubital tunnel which can potentially lead to irritation.Overuse of the elbow or prolonged positioning of the elbow in flexed position can lead to cubital tunnel syndrome.Anything that narrows the diameter of the tunnel such as soft tissue swelling, fluid imbalance, bone spurs, arthritis, or growths in or around the elbow joint can cause problems as well. Repetitive use of the hand and wrist on the keyboard and mouse may lead to swelling of the muscles around the tunnel.
What are the Symptoms of Cubital Tunnel Syndrome?
The elbows of those affected by cubital tunnel syndrome is often painful.The pain may be described as vague discomfort to severe pain and may progress from intermittent to constant.It may radiate up or down the arm.Symptoms in the hand include numbness and tingling in the pinky and lateral half of the ring finger.Grip strength may be decreased and fine motor movements of the hand and fingers may be compromised.The early symptoms of Cubital Tunnel Syndrome are exacerbated when the elbow is in a flexed position.
How is Cubital Tunnel Syndrome Diagnosed?
In addition to a careful history and physical exam, there are three maneuvers that can help aid in the diagnosis of cubital tunnel syndrome.In Tinel’s test, the doctor uses the fingertips to “thump” the cubital tunnel.In a positive test, this maneuver will reproduce the symptoms of cubital tunnel syndrome.In the elbow flexion test, the patient’s elbow is flexed, the forearm is palms down, and the wrist is extended for 30 seconds.If this provokes pain or numbness, it is diagnostic of cubital tunnel syndrome.The shoulder internal rotation test involves varying degrees of shoulder abduction with maximal internal rotation, flexion of the elbow, and the wrist held in a neutral position.Again, a positive result is suggestive of cubital tunnel syndrome.
Plain film X-rays of the elbow is taken to rule out deformity of the elbow from old trauma or bone spurs from arthritis. MRI, and high-resolution ultrasonography are sometimes obtained to assess for possible additional soft tissue injuries.
Electromyography and Nerve Conduction Studies can assess the severity of the condition or confirm a questionable diagnosis. NCV testing is normal in 20% of patients with Cubital Tunnel Syndrome.
How is Cubital Tunnel Syndrome Treated?
In mild-to-moderate cases conservative methods are utilized for a several months.The elbow is splinted at night in extension in a Pil-O brace. If night splinting is successful, it is recommended that it continue for an additional 6 weeks past the date of resolution in order to prevent recurrence.
NSAIDs, physical therapy, and avoidance of trauma to the elbow are additional vital components of a conservative approach to treatment. Ergonomic modifications of the workstation with frequent computer mouse and keyboard breaks may be beneficial.
If symptoms do not respond to conservative measures, there are several effective surgical techniques available. In decompression surgery, the cubital tunnel is made wider, releasing pressure on the ulnar nerve.With medial epicondylectomy, the cubital tunnel is made larger by removing a portion of the medial epicondyle.In anterior transposition procedures the ulnar nerve is moved to a position in front of the medial epicondyle and held in place with a sling created from fascia or the nerve is placed beneath the muscle.In this way the ulnar nerve no longer rubs or stretches when the elbow is flexed.
Use of a splint for 2-3 weeks post-surgery can be expected, as well as intensive physical therapy to strengthen the limb and prevent contractures.
How can Dr. Knight help you with cubital tunnel syndrome?
Dr. Knight has years of significant experience in peripheral nerve surgery such as cubital tunnel syndrome. While cubital tunnel syndrome is usually resolved with non-operative treatment, if surgery becomes necessary, Dr. Knight will carefully determine with your help what your daily activities are and what sports you enjoy to determine which minimally invasive procedure is best to return you to painfree activities quickly.
Note: The following video contains graphic images.
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