Ulnar Nerve Entrapment Causes and Treatment

Ulnar nerve entrapment occurs when there is too much pressure on the ulnar nerve. This nerve can be entrapped at the elbow or the wrist. Ulnar neuropathy symptoms include numbness in the hand, or tingling in the forearm and pinky side of your hand. It may cause pain, or progress to muscle weakness or atrophy (wasting away).

Ulnar nerve entrapment is a common neuropathy that affects a specific location. It's second only to carpal tunnel syndrome among this focused type. Treatment includes lifestyle changes and conservative measures like splinting or cortisone injection. Surgery may be needed if these methods do not provide relief.

Types

The ulnar nerve can be entrapped or compressed inside the elbow or the pinky side of the hand. There are two types of ulnar nerve entrapment that lead to different effects:

• Cubital tunnel syndrome, caused by entrapment or compression at the elbow. It is relatively common.
• Guyon's canal syndrome, caused by ulnar nerve compression in the wrist or hand. Guyon's canal syndrome is relatively rare.

These conditions can lead to nerve compression that affects sensation on the inside of your forearm, the pinky side of your hand, your pinky finger, and half of the ring finger. The nerve supplies muscles that help bend your wrists and fingers, spread your fingers apart, and bring them back together.

Symptoms

Ulnar neuropathy causes tingling, pain, and numbness along the path of the ulnar nerve in the forearm and hand. It occurs specifically inside the border of your forearm and hand and your fourth and fifth fingers.

When the ulnar nerve is compressed in the cubital tunnel of the elbow, you can experience these symptoms in both your forearm and hand. If your nerve is compressed in Guyon's canal, you will only have symptoms in your hand.

You may experience:

• Symptoms that come and go
• Symptoms at night due to the position of your arm while sleeping
• Symptoms that get better if the compression is relieved, such as stopping activities that put pressure on the elbow or wrist
• Muscles that can become weak. It can become hard to open jars, use a keyboard, or play a musical instrument.

You may have poor grip or pinch strength and trouble separating your fingers. In severe cases, these muscles atrophy. If severe ulnar nerve entrapment is left untreated, a condition that causes the fingers to bend toward the wrist can develop.

Causes

There are various causes for cubital tunnel syndrome and Guyon's canal syndrome. However, in some cases, they can develop without an apparent reason.

Cubital tunnel syndrome can be caused by the following:

• Leaning on the elbow for an extended period
• Stretching the nerve by repeatedly bending the elbow (such as in activities that require repetitive pulling or lifting). Throwing a baseball can sometimes irritate the ulnar nerve.
• Direct trauma to the inside of the elbow
• Arthritis
• Bone spurs
• Swelling in the elbow

Guyon's canal syndrome can occur from:

• Repetitive trauma, such as in manual labor, using power tools or a jackhammer
• Prolonged pressure on the hand (such as during bicycling, resting the body weight on the handlebar)
• Abnormal tendons, muscles, or blood vessels
• A fractured (broken) bone in the hand
• A cyst or tumor

Risk Factors

Activities that cause compression on ulnar nerves, such as bicycling and other sports, can lead to repetitive pressure on the wrist and elbow. A 2021 study of workers from Finland identified risk factors for ulnar nerve entrapment that led to hospitalization included:

• A history of smoking
• Physically demanding occupations
• Repetitive vibration on the hands
• Exposure to temperature changes
• Older age, typically between 40 and 50 years

Metabolic conditions like diabetes or obesity also may contribute to the risk, but there's no clear evidence of the relationship.

Diagnosis

You can suspect you have ulnar nerve entrapment based on where and when you feel numbness, tingling, or pain. Take notes so you can report this to a healthcare provider, including what you were doing when you experienced symptoms, especially the position of your wrist and elbow and if there was any pressure on those areas.

A healthcare provider will review your symptoms and perform a physical exam. They might use a Tinel's test by gently tapping over the nerve to see if it reproduces your symptoms. But this test along with flexion-compression tests won't always provide enough evidence to diagnose the condition.

A provider may recommend additional testing to confirm a diagnosis of ulnar nerve entrapment, including the following:

• Nerve conduction studies are the primary tests used to confirm a diagnosis of ulnar nerve entrapment and assess the condition's severity. These tests determine how quickly electrical impulses travel along the nerve and how muscles supplied by the nerve respond to stimulation.
• X-ray images can rule out other causes of pain, as well as arthritis or bone spurs that might compress the nerve.
• Ultrasound is used to look for physical damage to the nerve.
• Magnetic resonance imaging (MRI) scans provide pictures of soft tissue structures (such as muscles and tendons) and the nerve.

Treatment

Treatment for ulnar nerve entrapment depends on the severity of the condition. If you haven't yet developed significant muscle wasting, conservative treatment is usually recommended. This successfully improves symptoms without surgery in most cases.

Conservative treatment includes measures you can take at home and work. It consists of:

• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Advil or Motrin (ibuprofen) or Aleve (naproxen) for pain and to reduce inflammation
• Avoiding positions and activities that increase pressure on the nerve (such as on the ulnar nerve region or the wrist) or have prolonged elbow flexion. This can include typing with bent elbows, resting your elbows on the arms of a chair, driving while resting your arm on the open window, or triceps-focused strengthening exercises.
• Splinting at night to prevent full bending of the elbow. A homemade night splint can be made by wrapping a towel around your straight elbow. Or, you could wear an elbow pad backward.
• Nerve gliding exercises aimed at helping the ulnar nerve slide through its tunnel at the elbow and its canal at the wrist. While research has not proven their benefit, they may be recommended to perform at home or as part of physical therapy.

One ulnar nerve gliding exercise is to extend your arm straight in front of you with your palm up. Curl your wrist and fingers toward your upper body. Next, extend your open hand away from you, so the palm is up and wrist is bent down. Then, bend your elbow keeping the hand in that position.

Interventions used to treat ulnar nerve entrapment, alone or in combination, also can include:

• Medication, including steroid injections and Botox in some cases
• Physical therapy and strengthening exercises
• Transcutaneous electrical nerve stimulation (TENS)
• Cognitive behavioral therapy

Pulsed radiofrequency stimulation and cryoneurolysis (freezing techniques) also may be options used in combination with surgery.

Surgery

In some cases, nerve decompression surgery is required to relieve pressure on the ulnar nerve. If you have significant weakness or have signs of muscle damage or wasting, a healthcare provider may recommend surgery.

Procedures that may be recommended include:

• Cubital tunnel release: This surgery opens the roof of the cubital tunnel to decrease pressure on the nerve. The tissue heals and allows more space for the nerve.
• Ulnar nerve anterior transposition: This surgery moves the nerve so it doesn't get caught on the bone when you stretch your elbow.
• Medial epicondylectomy: This removes some of the elbow bone to help prevent the nerve from getting stretched when you bend your elbow.
• Removal of cysts, scar tissue, or growths: If ulnar nerve compression is due to these issues, they can be surgically removed.

Prognosis

Conservative treatment improves the symptoms of ulnar nerve compression at the elbow in nine out of 10 people. Early diagnosis and treatment of ulnar nerve entrapment leads to better prognosis for recovery and may allow time for therapies other than surgery to work.

Long-term nerve compression can lead to permanent loss of sensation and muscle use. Symptoms may decrease after surgery. However, it can take months to a year for the nerve to recover its normal sensation after surgery. You may benefit from a rehabilitation program and home exercises.

Summary

Ulnar nerve entrapment occurs when the nerve is compressed in the elbow or the hand and wrist. It can cause pain, tingling, and numbness along the inside of the forearm, pinky side of the hand, pinky finger, and half of the ring finger. Nerve entrapment is typically diagnosed with a physical exam and nerve conduction studies.

Treatment includes anti-inflammatory medications, splinting, nerve gliding exercises, and avoiding activities that increase nerve pressure. Occupational or physical therapy can also be beneficial. In severe cases, surgery might be required.