Cubital Tunnel Syndrome

Cubital tunnel syndrome refers to compression of the ulnar nerve at the media (inside) part of the elbow.  You may have noticed this nerve if you’ve ever bumped your “funny bone”.  Compression of the ulnar nerve at the elbow can cause numbness, tingling, and in severe cases, weakness.

Anatomy and Causes

The ulnar nerve provides sensation to your small finger, half of the ring finger, and a portion of the top of your hand.  This nerve also provides motor (muscle control) innervation to several of your fingers.  The ulnar nerve travels from the shoulder to the hand by crossing the medial side of the elbow.  There are several places along this path that the nerve can get pinched.  This nerve also gets slightly stretched with elbow flexion, which is why many patients with cubital tunnel syndrome get worse symptoms when their elbows are held in a flexed position for a prolonged period of time.

In some patients, the ulnar nerve is “unstable” and is able to flip back and forth over a small bony prominence at the elbow termed the medial epicondyle.  In this case, patients often describe a “zinging” or shooting pain down their arm with nerve instability.

Symptoms and Associations

Patients with cubital tunnel syndrome frequently complain about numbness and tingling in their fingers at night.  Patients may also notice symptoms when driving, holding a book or a phone, or typing for a prolonged period.  Straightening the elbow often improves these symptoms.  Some patients are able to localize their symptoms to the small finger side of their hand, though many patients describe a feeling of the entire hand being numb.  As compression on the nerve worsens, numbness and tingling become more frequent and may be present all of the time.  In very severe cases, patients develop weakness and atrophy in muscles innervated by the ulnar nerve, including some finger flexor muscles as well as in some of the small muscles in their hands.

Treatment

The goal in treating cubital tunnel syndrome is to reduce or eliminate symptoms and to prevent worsening injury to the ulnar nerve.  In some cases, nerve studies can be useful to help isolate the location of nerve symptoms and quantify their severity.

Non-operative

The initial treatment for most patients with cubital tunnel syndrome is non-operative.  Non-operative treatment for cubital tunnel syndrome involves activity modifications to avoid holding the elbow flexed for prolonged periods of time.  Treatment may also include wearing elbow splints or sleeves at night to prevent elbow flexion.  Working with a hand therapist may be helpful to develop strategies to prevent further nerve irritation or injury.  The majority of patients improve substantially with these measures, and relatively few patients progress to needing surgery.

Operative

Surgery for cubital tunnel syndrome is reserved for patients with severe symptoms and for those who have ongoing symptoms despite appropriate non-surgical treatments.  The surgery, cubital tunnel release, involves making a small incision on the inside part of the elbow and releasing any tight structures overlying the ulnar nerve.  In cases where the ulnar nerve is unstable, the nerve may be moved in front of the medial epicondyle to prevent ongoing symptoms.  This is termed a transposition.  Cubital tunnel release is a common procedure as is performed on an outpatient basis with no need to stay in the hospital after surgery.