What is ulnar nerve entrapment at the elbow?
The ulnar nerve (also called cubital nerve) provides the sensitivity to the 4th and 5th fingers.
It also innervates most of the muscles of the hand that spread and close the fingers and the pinch between the thumb and index finger.
The ulnar nerve compression is usually located at the elbow. Many potential causes of compression are known and include tendons, ligaments, bone or vessels.
Who is affected by this compression?
Ulnar nerve entrapment at the elbow is common in the general population, usually with no definite cause.
Sometimes a cause can be identified as a fracture of the elbow in childhood, osteoarthritis of the elbow or dislocation of the nerve during elbow flexion.
Specific diseases can increase the sensitivity of the nerve to compression, such as diabetes , haemophilia , leprosy , kidney failure …
Similarly, prolonged or repeated compression may be a predisposing factor such as a position in surgery under general anaesthesia, abduction cushion after shoulder surgery, line work and some sports such as golf or baseball.
What are the symptoms of ulnar nerve entrapment?
Compression of the ulnar nerve at the elbow results in pain, tingling and numbness of the ring and especially the little finger. Ascending pain to the elbow is common.
These signs can occur during the day or the night and are often increased with elbow flexion.
In severe cases, symptoms progress to loss of grip and pinch strength and difficulty to spread and close the fingers. The ring and little fingers may develop a claw deformity and progressive loss of sensation.
Severe longstanding compression may lead to irreversible deficiency even after surgical decompression.
What additional tests will you need?
– Radiography of the elbow is not systematic.
It can detect a narrowing of the nerve tunnel by bone secondary to previous trauma or osteoarthritis.
– Electromyography (EMG) measures the ability of the ulnar nerve to transmit electrical signals for sensory or motor function.
EMG can confirm the entrapment, locate the site of compression and find an anomaly on the other nerves of the arm.
EMG is not dangerous, but it is sometimes a bit unpleasant and is not 100% reliable.
When compression of the ulnar nerve is recent, symptoms may disappear with rest and elbow splinting.
If this treatment does not work, surgery becomes necessary. The main goal of surgery is to release compression of the nerve. Many different techniques are used and there is no strong evidence that one technique is better than another. My belief is that it is important to see the nerve along a sufficient length so as not to miss a compression site. I also believe that it is important to preserve the vascularity and the gliding tissues around the nerve.
In some cases, bone resection or re-routing of the nerve itself outside the compression zone is required.
It is usually possible to leave the hospital on the day of surgery.
The symptoms gradually disappear within several weeks or months. The recovery is not always complete. Nerve recovery prognosis is based on the severity of the initial compression, its duration and the capacity of nerve regeneration. Age is a key factor in nerve regeneration.
Usually postoperative splint is not required, and early mobilization of the elbow, shoulder and hand are recommended. The postoperative sling should be abandoned after two to three days.
If a brace is required, it will be kept for three weeks.
You will see your surgeon between one to three weeks after surgery.
In case of manual work, time off work varies from one to three months.
Rehabilitation may be prescribed, but not always.
Ulnar nerve compression at the elbow results in tingling in the ring and little fingers and loss of grasp and pinch strength.
When compression is mild, these symptoms may disappear with rest and splint. Otherwise, surgery usually provides a progressive and permanent relief.
An informed consent form will be given before surgery. We hope to inform you as objectively as possible of the principles of intervention, but also the risk of potential complications.