Common Upper Extremity Entrapment Neuropathies

Common Upper Extremity Entrapment Neuropathies

by Ehab Yasin, DO and Susan Sorosky, MD

Carpal Tunnel Syndrome

What is it?

Carpal tunnel syndrome (CTS) or neuropathy of the median nerve at the wrist is the most common entrapment neuropathy. The median nerve runs down the forearm and then through the carpal tunnel which is a small passageway surrounded by bones and ligaments in the wrist. The median nerve then supplies sensation to the thumb, index, and middle finger and strength to the base of the thumb. CTS results from the nerve being inflamed or compressed in the carpal tunnel. 

How does it occur?

It is a common misconception that only people who use a keyboard regularly or work on an assembly line get CTS. In fact, many different things contribute to CTS including most commonly, repetitive motion. There are also several diagnoses associated with CTS including obesity, diabetes, rheumatoid arthritis, hypothyroidism, and kidney failure. CTS also commonly occurs during pregnancy. Finally, a wrist fracture can narrow the carpal tunnel and irritate the nerve. Many times, there is no single cause, but a combination of risk factors that contributes to developing CTS. 

What are the symptoms?

Common symptoms of CTS include pain, numbness and tingling in the hand, especially the thumb, index, and middle fingers. These symptoms can also radiate into the forearm. Symptoms are typically worse at night and when holding a steering wheel, book or phone, and are relieved with shaking the hand. As the disease progresses, other symptoms include constant numbness of the fingers, wasting (atrophy) of the muscles of the palm near the thumb, and decreased hand strength (i.e. dropping objects, difficulty manipulating small objects, weak grip). 

How is it diagnosed?

CTS is typically diagnosed with a thorough history and physical examination of the neck and upper extremities, and then confirmed with an electrodiagnostic study (EMG/NCS). The electrodiagnostic study determines how severely the median nerve is compressed in the carpal tunnel, and also rules out other diagnoses with similar presentations. The results of the study typically dictate the type of treatment provided and can also predict how a patient will respond to surgery.

How is it treated?

There are several ways to treat CTS which focus on relieving pressure on the median nerve at the level of the wrist and modifying any contributing repetitive motion.  A common initial strategy includes a resting wrist splint to hold the wrist in a neutral position; mild CTS symptoms are often controlled by wearing the splint only at night. In addition, it is important to keep the wrist in a good position ergonomically with proper keyboard and mouse positioning so it is not bent up or down. Avoiding overuse, taking short breaks, typing more softly, and relaxing grip are also important. Your provider may prescribe hand therapy which treats CTS with nerve gliding, stretching and exercise. In addition, it is important to treat any diseases (see How does it occur?) that may be associated with CTS.

If these conservative measures fail to control the symptoms, anti-inflammatory and/or neuropathic (nerve pain) medications may be prescribed. An ultrasound-guided corticosteroid injection near the median nerve in the carpal tunnel can also provide relief. If the electrodiagnostic test shows severe CTS, then surgical release of the carpal tunnel may be necessary to avoid permanent damage to the nerve.

 

Cubital Tunnel Syndrome

What is it?

Cubital tunnel syndrome or neuropathy of the ulnar nerve at the elbow is another common entrapment neuropathy in the upper extremity. The ulnar nerve passes along the inside of the elbow and then enters a small tunnel referred to as the cubital tunnel. This is a tight space made up of bone on one side and ligament on the other. The ulnar nerve then supplies sensation to the ring and little fingers and strength to the hand muscles. Cubital tunnel syndrome results from the nerve being inflamed or compressed in this tunnel. 

How does it occur?

Cubital tunnel syndrome can result from a number of different mechanisms including repetitive motion (i.e. throwing or hammering) and repeated pressure on the inside of the elbow (i.e. resting the elbow on hard surfaces). Other contributions to ulnar neuropathy include arthritis, fractures/trauma, dislocations and masses. Finally, ulnar neuropathy at the elbow can also result from nerve instability meaning the tunnel is too loose and the nerve moves more than it should. 

What are the symptoms?

Common symptoms of cubital tunnel syndrome include pain, numbness and tingling in the inside part of the elbow and forearm into the hand, especially the ring and little fingers. As the disease progresses, other symptoms include constant numbness of the fingers, wasting (atrophy) of the hand muscles including the palm side near the fifth finger, and decreased hand strength (i.e. grip and fine motor function). 

How is it diagnosed?

Cubital tunnel syndrome is typically diagnosed with a thorough history and physical examination of the neck and upper extremities, and then confirmed with an electrodiagnostic study (EMG/NCS). The electrodiagnostic study determines how severely the ulnar nerve is compressed in the cubital tunnel, and also rules out other diagnoses with similar presentations. The results of the study typically dictate the type of treatment provided and can also predict how a patient will respond to surgery.

How is it treated?

There are several ways to treat cubital tunnel syndrome including relieving pressure on the ulnar nerve at the elbow and modifying any contributing repetitive motion. A common initial strategy uses an elbow pad to protect the ulnar nerve. In addition, it is important during sleep to keep the elbow straight with use of a towel around the elbow or wearing an elbow pad in reverse or an elbow splint. In addition, if the problem is related to repetitive motion, those motions should be avoided (i.e. leaning on the elbow) or modified as appropriate. Your provider may prescribe physical therapy or hand therapy which treats ulnar neuropathy at the elbow with nerve gliding, stretching and exercise. 

If these conservative measures fail to control the symptoms, anti-inflammatory and/or neuropathic (nerve pain) medications may be prescribed. Hydrodissection around the ulnar nerve using saline to separate the nerve from the surrounding tissue can also provide relief. If the electrodiagnostic test shows severe ulnar neuropathy, then surgical release of the cubital tunnel or moving the ulnar nerve out of the tunnel may be necessary to avoid permanent damage to the nerve.

If you have any questions about carpal tunnel syndrome or cubital tunnel syndrome, please do not hesitate to reach out to us at Desert Spine and Sports Physicians where we are dedicated to the diagnosis and non-surgical management of spine, sports and musculoskeletal injury.

 

References:

Brukner, P. and Khan, K.; Brukner & Khan’s Clinical Sports Medicine. 5th ed. pp.485-486.

Preston D. and Shapiro, B.; Electromyography and Neuromuscular Disorders:  Clinical and Electrophysiologic Correlations.  3rd ed. pp. Ch. 17.



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