Cubital tunnel syndrome causes numbness in some fingers

Dr. Ryan D. Katz
Dr. Ryan D. Katz (Kim Hairston, Baltimore Sun)

Most people have heard of carpal tunnel syndrome, and likely even know someone who suffers from it. Cubital tunnel syndrome is less common but also can cause debilitating symptoms, such as numbness in the ring and little fingers and wasting of muscle in the hand. More men than women suffer from the disorder, which can be caused by repeatedly leaning on your elbow or bending your arm for long periods of time. Dr. Ryan Katz, attending hand surgeon at the Curtis National Hand Center at Union Memorial Hospital, answers questions about its cause and treatment.

What is cubital tunnel syndrome, and how does it differ from carpal tunnel syndrome?

Cubital tunnel syndrome is a symptom complex of numbness, tingling and sometimes weakness in the hand. It is analogous to carpal tunnel syndrome but affects different digits and muscles. Carpal tunnel syndrome primarily causes numbness and tingling in the thumb, index and long finger, and weakness in the muscles at the base of the thumb. Cubital tunnel syndrome can cause numbness and tingling in the ring and small finger and weakness of the entire hand. The carpal tunnel, where the median nerve can get pinched, is located at the wrist. The cubital tunnel, where the ulnar nerve can get pinched, is located on the inside of the elbow. When you hit your "funny bone," you are essentially irritating the ulnar nerve at the level of the cubital tunnel.

Is it exclusively caused by pressure on the nerve?

There is debate as to whether the nerve symptoms arise from pressure, tension or both. Both phenomena cause a decrease in blood flow to the nerve and can result in nerve symptoms.

What are the symptoms and how is it diagnosed?

Diagnosis of cubital tunnel syndrome begins with a careful history and physical. One must first rule out other causes of nerve symptoms. The causes can include, but are not limited to, stroke, cervical spine injury, spinal cord pathology, intrinsic nerve pathology, dietary deficiency, infectious disease and previous trauma. The patient with cubital tunnel syndrome will often complain of numbness and tingling in the ring and small finger. They may also complain of weakness in the hand. Physical examination will demonstrate decreased sensitivity to touch in the ring and small finger as compared to the index finger. The physician may also be able to detect weakness in the hand and, in long-standing, severe cases, wasting of the small muscles of the hand. The diagnosis may be aided with electrophysiologic studies.

When is it time to see a doctor?

If one has persistent numbness and tingling in the ring and small finger or notes wasting or weakness in the hand, seeing a hand specialist is advised.

When is physical therapy advised, and when is surgery needed?

Physical therapy and nighttime extension splinting can be of benefit for mild cases of cubital tunnel syndrome. Surgery would be advised on a case-by-case basis. Some patients who may benefit from surgery include those who have failed to improve despite conservative treatment with extension splinting, those patients whose symptoms worsen despite conservative treatment, or those with advanced disease and evidence of weakness and early muscle wasting.

Can a sufferer expect to be pain-free after treatment?

Patients with cubital tunnel syndrome usually complain of numbness and tingling more than pain. Though nerve recovery can be unpredictable, surgical treatment often provides symptom relief in patients with isolated cubital tunnel syndrome.



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