PT Tip of the Month

Cubital Tunnel Syndrome

Cubital tunnel syndrome is the second most common peripheral nerve entrapment syndrome in the body. Not only does it cause a significant amount of discomfort to those affected, but it can progress to loss of function in the hand. Cubital tunnel syndrome occurs when the ulnar nerve becomes compressed or irritated on the inside aspect of the elbow. It is the most common site of entrapment for the elbow and affects men three to eight times more than women.

Anatomy

The ulnar nerve is derived from the nerve roots of the cervical spine and travels down the arm to innervate many muscles of the forearm and hand. It also provides sensation to a portion of our forearm, hand and the fourth and fifth fingers. At the elbow, this nerve runs through a tunnel of tissue under a bump of bone in the elbow, known as the cubital tunnel. This is the location we think of when we hit our "funny bone." The sensation associated with our "funny bone" is actually a sudden irritation to the ulnar nerve in this space. The cubital tunnel is only approximately 4 mm wide, therefore an easy spot of compression to the ulnar nerve. As our elbow bends and straightens, the ulnar nerve must glide freely through this tunnel. When our elbow is fully bent, the cubital tunnel narrows, causing a 55% reduction of the canal and therefore increasing pressure on this nerve.

Causes/Risk Factors

Cubital Tunnel Syndrome is most common in individuals with jobs that require prolonged periods of time with the elbow bent, such as talking on the phone. Additionally, when the elbow is bent and rested on a hard surface this further increases the pressure on the nerve, making those with poor computer ergonomics also at risk. Health factors such as obesity and diabetes mellitus can also contribute to the development of this syndrome. Other pathologies such as musculoskeletal disorders (like golfer's elbow), elbow fractures, dislocations, swelling, arthritis or cysts can contribute as well.

Symptoms

Characteristic symptoms of cubital tunnel syndrome include achy pain on the inside of the elbow, paresthesia, or a sense that your ring and little finger are "falling asleep", and numbness and tingling in the ring and little finger. Many of these symptoms can come and go and are more common when the elbow is bent for prolonged periods. This usually means that individuals will wake up in the morning or in the middle of the night with numbness, as many people curl their arms and legs into their body as they sleep. As cubital tunnel syndrome progresses, weakness of the grip or difficulty with coordinating finger movements can occur. As this persists with prolonged and sustained compression, muscle atrophy in the hand can occur.

Treatment

A positive diagnosis does not immediately indicate a need for surgery, and many clinicians emphasize patient education as the main treatment. To reduce pressure on the ulnar nerve, avoid activities that require keeping the arm bent for prolonged periods. If your job requires a significant amount of computer work, adjust your desk space to ergonomic recommendations so you do not need to rest your elbows all day. If symptoms persist or begin to impede daily activities, it is important to see your doctor. When diagnosed appropriately, this condition can be treated both conservatively or operatively. Once diagnosed with a physical exam, many doctors will recommend non-steroidal anti-inflammatory medications to reduce swelling around the nerve. Cortisone injections are also occasionally used for this purpose as well. Your doctor may also prescribe a brace or splint to wear at night to prevent you from sleeping with your elbow in a bent position.

Another conservative treatment is physical therapy and physical therapists can also evaluate and diagnose this condition. Physical therapy will focus on reducing inflammation and tightness of the elbow around the nerve, restoring appropriate posture and strengthening muscles that may have minor weakness due to the nerve entrapment. Nerve glide exercises can also be utilized. These exercises help to facilitate the ulnar nerve to glide freely through the cubital tunnel as it should. These exercises can not only prevent stiffness of the elbow and wrist but also reduce the frequency of tingling or numbness.

Lastly, your doctor may recommend surgery to take pressure off the nerve if conservative treatments have not managed your symptoms or if severe compression has resulted in muscle weakness and wasting. The two most common procedures performed are a cubital tunnel release or an ulnar nerve anterior transposition. For the cubital tunnel release, the band of tissue that covers the nerve to create the roof of the cubital tunnel is cut to increase the space for the nerve and decrease pressure. This is frequently indicated when nerve compression is more mild. More commonly, the nerve is moved from its place in the back of the elbow to a new place in the front of the forearm. This is known as an ulnar nerve anterior transposition. Moving the nerve prevents it from getting caught on the bony ridge of the elbow when the elbow bends.

If you think you are experiencing signs and symptoms of cubital tunnel syndrome and would like to be scheduled for a physical therapy evaluation, please call 617-232-PAIN (7246) for our Brookline office or 617-325-PAIN (7246) for our West Roxbury office.

References:

  1. Cutts S. Cubital tunnel syndrome. Postgrad Med J. 2007;83(975):28-31.
  2. Verheyden J, Palmer A. Cubital Tunnel Syndrome. Available at http://emedicine.medscape.com/article/1231663-overview#showall.
  3. McPherson SA, Meals RA. Cubital tunnel syndrome. Orthop Clin North Am. Jan 1992;23(1):111-23.
  4. American Academy of Orthopedic Surgeons. Ulnar Nerve Entrapment at the Elbow (Cubital Tunnel Syndrome) Available at: http://orthoinfo.aaos.org/topic.cfm?topic=a00069.
  5. Elhassan B, Steinmann SP; Entrapment neuropathy of the ulnar nerve. J Am Acad Orthop Surg. 2007 Nov;15(11):672-81

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