Cubital tunnel syndrome results when the ulnar nerve (the “funny bone” nerve) becomes compressed or squeezed as it passes through the cubital tunnel along the inner side of the elbow. The cubital tunnel of the elbow is formed by the bony prominence of the distal humerus called the medial epicondyle, tissue bands of the forearm muscle, and a ligament that overlie the ulnar nerve. When the elbow is maintained in a flexed position, particularly for a prolonged period of time or repetitively, pressure within the cubital tunnel increases which causes compression of the ulnar nerve. When the nerve is squeezed and under increased pressure, the blood supply to the nerve is decreased which can cause a wide variety of symptoms. In some cases, repetitive snapping of the ulnar nerve with vigorous motion of the elbow can produce inflammation of the nerve, called neuritis, which may also cause symptoms of cubital tunnel syndrome. Most patients commonly experience the following symptoms:
Symptoms can range from mild to severe depending on the degree of nerve compression or entrapment. Typically initial symptoms are intermittent or mild, but with long term compression (months to years) the axons or small “wires” within the nerve become damaged which can cause constant or even permanent symptoms. Occasionally, acute ulnar nerve entrapment can be severe and cause symptoms of constant numbness and hand weakness with loss of grip strength. When the ulnar nerve becomes severely affected, atrophy and weakness of the hand can become very obvious and become permanent. A full recovery of the ulnar nerve’s function can be expected with early recognition and treatment.
Treatment for cubital tunnel syndrome usually begins with conservative care for mild or moderate nerve compression or entrapment. If patients present with more advanced ulnar nerve compression or failed conservative treatment, surgery is usually recommended to avoid potential long term changes to the nerve.
Conservative treatment methods include splinting or padding to prevent elbow flexion with sleep, ergonomic training to avoid excessive elbow flexion with activity, and use of anti-inflammatory medications. A corticosteroid (“cortisone”) injection is not offered for cubital tunnel syndrome as risk of injury can occur to the nerve based on its anatomy about the elbow. Patients with mild cubital tunnel syndrome can generally experience improvement or complete resolution of symptoms following these treatment recommendations. If symptoms persist after a reasonable effort to treat conservatively or signs of worsening ulnar nerve compression are evident, surgery is recommended.
Surgery has been proven very effective in the treatment of cubital tunnel syndrome. There are various techniques described for decompression of the ulnar nerve at the elbow. Surgery can be limited to an in situ release (leaving the nerve in its anatomic “bed”) or release with transposition of the ulnar nerve (moving the nerve from its anatomic “bed” to a new position). Surgical release involves dividing the ligament (the “roof” of the cubital tunnel) and muscle fascia or bands to decrease pressure or any constriction around the nerve. With moving or transposition of the ulnar nerve, the nerve is moved to the front of the elbow and kept in place with a sling surgically created from muscle fascia or by placing the nerve within or beneath muscle.
Results, no matter the type of surgery, typically have very similar outcomes. For mild or moderate cubital tunnel syndrome, patients can expect complete relief of symptoms and full recovery of the nerve. However, for severe cubital tunnel syndrome, symptoms such as weakness and persistent numbness can become permanent despite surgical release. Release or decompression of the nerve for severe cases will prevent the nerve from further damage, improve or eliminate symptoms of pain and tingling, and could possibly allow for some recovery of nerve function over months. Dr. Katz will help you determine your best options for treatment and will discuss expectations of recovery.