Ulnar Nerve Entrapment / Instability

Ulnar nerve entrapment, also known as cubital tunnel syndrome or ulnar neuropathy, is a condition characterized by the compression or irritation of the ulnar nerve as it travels through a narrow passageway on the inner side of the elbow known as the cubital tunnel.  It can also become entrapped at the wrist. When the ulnar nerve becomes compressed, it can lead to pain, numbness, tingling, and muscle weakness in the hand and arm.

In the overhead throwing athlete, this is more particularly important when the nerve is unstable and moves irregularly with elbow flexion. This motion is known as subluxation and often requires surgical treatment with a procedure known as ulnar nerve transposition.

Ulnar nerve entrapment can result from various factors that cause pressure on the ulnar nerve, including:

1. Keeping the elbow bent for extended periods, such as while holding a phone or sleeping with the arm under the pillow, can increase pressure on the ulnar nerve.
2. Prolonged direct pressure such as leaning on the arm, or an arm rest or elbow can compress the nerve causing a sensation that the ring and small fingers have fallen asleep.
3. A blow to the inner side of the elbow, commonly referred to as hitting the “funny bone,” can compress the ulnar nerve.
4. Activities that involve frequent bending and straightening of the elbow, such as typing, hammering, or playing certain sports, can lead to ulnar nerve compression / instability over time.
5. Some individuals may have a naturally narrower cubital tunnel or other anatomical variations that increase the risk of nerve entrapment.
6. Conditions like arthritis or a previous injury that causes swelling or inflammation around the elbow can compress the nerve.
7. People with diabetes are at increased risk of developing nerve entrapment.
8. Bony growths or cysts near the cubital tunnel can put pressure on the ulnar nerve.
9. The risk of ulnar nerve entrapment increases with age.

The symptoms can vary depending on the severity and duration of nerve compression. Common symptoms include:

1. Numbness and tingling in the ring and little fingers, especially when the elbow is bent. This can come and go.
2. Difficulty gripping objects or performing tasks that require fine motor skills, such as holding a pen, typing or playing a musical instrument.
3. Chronic compression may lead to muscle wasting or atrophy in the hand, especially in the small muscles of the hand that control finger movement.
4. Pain in the elbow and hand.

Dr. Zahab Ahsan will review your medical history, inquire about your symptoms and any injuries to the arm. He will perform a physical exam to assess the areas that are numb, weak or painful. He may also tap on the nerve (Tinel’s sign) to see if it elicits tingling in the fingers.

Dr. Ahsan may order nerve conduction studies and an electromyograph to evaluate the electrical activity of the muscles and nerves to help pinpoint the location and severity of the nerve compression. In some cases, X-rays, ultrasound, or MRI may be ordered to identify any structural abnormalities, such as bone spurs, cysts, or tumors, that could be compressing the nerve.

Treatment for ulnar nerve entrapment depends on the severity of the symptoms and the underlying cause. Options may include:

1. Conservative nonsurgical treatment
   • Use of NSAID anti-inflammatory drugs to reduce swelling and treat discomfort.
   • Wearing a padded brace or splint, especially at night, to keep the elbow in a neutral position and reduce nerve compression.
   • Avoiding activities that exacerbate symptoms and taking breaks to prevent prolonged elbow flexion.
   • Physical Therapy to strengthen the muscles around the elbow and improve flexibility, which can alleviate pressure on the nerve.
   • Sometimes oral steroids may be recommended to reduce inflammation around the nerve. Steroid injections are not recommended as they can damage the nerve.

2. Surgery

The aim of surgery is to take pressure off the nerve. It is typically outpatient surgery.

Recovery can take three months or more. Surgery may be recommended when conservative measures are unsuccessful, and symptoms persist or worsen. Options include:

• Cubital Tunnel Release: This decompression procedure involves enlarging the cubital tunnel to relieve pressure on the ulnar nerve.
• Ulnar Nerve Transposition: The nerve is moved from its original position behind the elbow to a new location in front of the elbow to prevent it from being compressed. This is typically the preferred treatment for overhead throwing athletes with ulnar nerve subluxation.