Cubital tunnel syndrome (CBTS) is peripheral nerve compression syndrome. It is an irritation or injury of the ulnar nerve in the cuboidal tunnel at the elbow.It is the second most common compression neuropathy in the upper extremity after carpal tunnel syndrome.It is a major source of discomfort for the patient and in extreme cases can lead to loss of function of the hand. Patients often present with both sensory and motor deficits.The degree of sensory and motor defects determines treatment recommendations, ranging from conservative to surgery.
Ulnar Nerve Anatomy and Cubital Tunnel
The cubital tunnel, which sits over a gap of approximately 4 mm between the medial epicondyle and olecranon, is formed by the retinaculum. In turn, the bottom of the tunnel is formed by the capsule and posterior band of the medial collateral ligament of the elbow joint. It contains several structures, the most important of which is the ulnar nerve.
The ulnar nerve is the terminal branch of the medial cord of the brachial plexus and contains fibers from the C8 and T1 spinal nerve roots. It lowers the arm just anterior to the medial intermuscular septum and then pierces this septum for the last third of its length. Proceeding below the septum and adjacent to the triceps muscle, it passes through the cubital tunnel to enter the forearm, where it passes between the two heads of the flexor carpi ulnaris muscle.
This anatomical arrangement has two implications for the nerve. Firstly, the ulnar follows a relatively restricted path, and secondly, it is located at some distance from the axis of rotation of the elbow joint. Movement of the elbow therefore requires both stretching and sliding of the ulnar nerve along the cubital tunnel. Although the nerve itself can extend up to 5 mm, slipping has the greatest role in this process.
The unusual anatomy of the cubital tunnel and the well-known increase in intraneural pressure associated with elbow flexion are believed to be key issues in the pathogenesis of cubital tunnel syndrome. Also, the shape of the tunnel changes from oval to an ellipse with elbow flexion. This maneuver also narrows the channel by 55%. Elbow flexion, wrist extension, and shoulder abduction increase intraneural pressure sixfold.
Causes of Cubital Tunnel Syndrome
Pressure on the ulnar nerve is a common cause of symptoms. The ulnar nerve is quite superficial at the medial epicondyle point; this is why people may experience pain and electric shock sensations in the forearm when accidentally bumping their elbow on a hard surface.
Stretching of the ulnar nerve can also cause similar symptoms. The ulnar nerve lies behind the medial epicondyle. Due to this anatomical position during flexion of the elbow joint, the ulnar nerve is stretched. Repetitive elbow flexion and extension can cause further damage and irritation to the ulnar nerve. Some individuals sleep with their elbows bent, which can stretch the ulnar nerve for long periods of time. This can cause injury to the ulnar nerve.
- When a nerve is subjected to direct or repeated trauma, the nerve can become painful and sensitive to movement or pressure. If the nerve swells, it may begin to act on the nerve’s ability to transmit impulses from the body to the brain, and vice versa. If this happens, you may experience altered or decreased sensation and/or reductions in muscle strength.
- Bending your elbow for a long time or bending your elbow repeatedly can cause painful symptoms as it can irritate the ulnar nerve.
- In some people, the nerve slides out from behind the medial epicondyle when the elbow is bent. Over time, this gliding back and forth can irritate the nerve.
- Leaning on your elbow for a long time can put pressure on the nerves.
- Fluid buildup in the elbow can cause swelling that can compress the nerve.
- A direct blow to the inside of the elbow can cause pain, electric shock sensations and numbness in the little and ring fingers.
- Sometimes cubital tunnel syndrome is caused by abnormal bone growth at the elbow or intense physical activity that increases pressure on the ulnar nerve. For example, baseball pitchers have a greater risk of cubital tunnel syndrome.
- Repetitive overhead activities, traction, subluxation of the ulnar nerve through the ulnar groove, metabolic disorders, congenital deformities, synovial cysts, anatomical irregularities, arthritis, joint inflammation and occupational athletic factors are also caused.
- Injuries to the elbow joint (fractures, dislocations, swellings, effusions) can cause anatomical damage to cause symptoms due to ulnar nerve compression/irritation.
What Are the Symptoms of Cubital Tunnel Syndrome?
The presenting complaint is typically one of “stinging and pricking” in the forearm and hand. The tingling sensation is usually present along the middle half of the little finger and ring finger. Symptoms are often exacerbated by elbow flexion. These symptoms may be present temporarily at first and then gradually worsen. On examination, findings may include reduced or complete loss of sensation on the palm and back of the little finger and, in advanced cases, the middle part of the ring finger.
Motor symptoms are less common and usually occur in severe cases of ulnar neuropathy. Patients may complain of weakness in the hand and frequent falling of objects. On examination, findings can range from mild weakness of the interosseous muscles to severe atrophy of the inner parts of the hand and weakness of the grip. The Froment sign may be positive, indicating weakness of the adductor pollicis supplied by the ulnar nerve.
How Is Cubital Tunnel Syndrome Diagnosed?
Diagnosis is made by electro-physiological studies and imaging findings, as well as patient history and physical examination.
High-resolution neuro-ultrasonography shows changes in the size and position of the ulnar nerve at the elbow.
Magnetic resonance neurography (MRN) shows the structural changes of the ulnar nerve and its surroundings.
X-rays can be used to look for degenerative changes of the cervical spine and elbow, as well as bone compression from previous fractures.
Electromyogram (EMG): This test checks nerve and muscle function and can be used to test forearm muscles controlled by the ulnar nerve. If the muscles are not working as they should, it may be a sign that there is a problem with the ulnar nerve.
Elbow level ulnar nerve entrapment neuropathies are staged as mild, moderate and severe according to the McGowan classification based on physical examination findings:
- Stage 1: Mild paraesthesia, hypoesthesia in the ulnar nerve area. There is no loss of strength in the muscles.
- Stage 2 : Moderate loss of strength in muscles with mid-ulnar innervation. There is minimal atrophy.
- Stage 3: Significant atrophy of muscles with severe ulnar innervation. There is significant atrophy of the hand intrinsic muscles. The claw may or may not be a hand.
Treatment in Cubital Tunnel Syndrome
Unless your nerve compression is causing too much muscle wasting, nonsurgical treatment will most likely be recommended first. Conservative treatment measures focus on pain relief, inflammation reduction, and rehabilitation. This includes patient education and behavior modification, non-steroidal anti-inflammatory drugs (NSAIDs), night splints, elbow pads, physical therapy, ultrasound, pulsed signal therapy, and corticosteroid injections.
Non-steroidal anti-inflammatory drugs: If your symptoms have just started, your doctor may recommend an anti-inflammatory drug such as ibuprofen to reduce swelling around the nerve. Although steroids such as cortisone are very effective anti-inflammatory drugs, steroid injections are not usually used because of the risk of nerve damage.
If non-surgical methods do not improve the condition, if the ulnar nerve is very compressed, if nerve compression has caused significant muscle weakness or damage, surgery may be recommended to take pressure off the nerve.
Physiotherapy in Cubital Tunnel Syndrome
Conservative treatment has been shown to have a 90% success rate in acute ulnar irritation, and symptoms often resolve within 2-3 months.
Conservative treatment may include: splinting, activity modification, electrotherapy modalities, anti-inflammatories, soft elbow pads, neural gliding, exercise, and patient education.
The initial goal of conservative treatment for cubital tunnel syndrome is to control and reduce paresthesia and pain. When symptoms are mild and aggravating activities are identified, the first step is to eliminate those activities that provoke pain.
Therapy begins with education about the development of symptoms and how certain activities can affect these symptoms.
Besides training, securing the elbow with splints can reduce swelling and help locate nerve irritation. Properly separating the elbow allows the nerve and surrounding structures to rest and relieve from traction and compression. Splinting is designed to relieve symptoms and prevent progressive dysfunction of the nerves.
Ice application can also help reduce pain and swelling and can be combined with gently applied active range of motion exercises. Ultrasound therapy is also an option, but it should be used appropriately and with caution, as it can cause further nerve damage and slow the rate of recovery if not used at an appropriate intensity.
Active range-of-motion exercises should be started within the comfort range, stretching within tolerance, and only after pain levels have subsided.
Exercises for Cubital Tunnel Syndrome
1) Elbow Flexion and Wrist Extension
Time required: 3 minutes
Sit tall in a chair and bring the affected arm by your side, level with your shoulder, with your hand facing the floor. Now point your fingers towards the ceiling, then bend the arm and bring it towards your shoulder. Repeat slowly 5 times.
2) Front Arm Flexion
Time required: 3 to 6 minutes
Sit tall in a chair and align the affected arm with the shoulders with the elbow straight in front of you. With your palm facing the ceiling, bend your wrist down to point your fingers toward the floor. Now bend the elbow and bring your wrist towards the face. Repeat slowly 5 to 10 times.
3) Head Tilt
Time required: 3 minutes
Sit tall in a chair and extend the affected arm to the side with the elbow straight and in line with the shoulder. Make sure your hand is facing the ceiling. Tilt your head away from your hand until you feel a nice stretch. Return to the starting position and repeat slowly 5 times.
Sit tall in a chair and extend the affected arm to the side with the elbow straight and in line with the shoulder. Make sure your hand is facing the ceiling. Bring your thumb and index finger together in a circle to make the OK sign. Now bend your elbow and bring your hand towards the face, wrap the remaining three fingers around the ear and chin and place the OK sign over your eye. Hold the position for 3 seconds, then return to the starting position and repeat the exercise 5 times.
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2-)Shah CM, Calfee RP, Gelberman RH, CA Goldfarb. Outcomes of Rigid Night Splinting and Activity Modification in the Treatment of Cubital Tunnel Syndrome. J Hand Surg. 2013; 38(6): 1125–1130.
3-)Lund AT, Amadio PC. Treatment of cubital tunnel syndrome: perspectives for the therapist. J Hand Ther. 2006;19(2):170-8.