Ulnar Nerve Entrapment (Cubital Tunnel Syndrome)

What is ulnar nerve entrapment (cubital tunnel syndrome)?

Cubital tunnel syndrome is a condition characterised by the compression of the ulnar nerve in an area of the elbow called the cubital tunnel.

The ulnar nerve travels down the back of the elbow, behind the bony bump called the medial epicondyle, and through a passageway called the cubital tunnel. The cubital tunnel is a narrow passageway on the inside of the elbow formed by bone, muscle and ligaments with the ulnar nerve passing through its centre. The roof of the cubital tunnel is covered by a soft tissue called fascia.

When the elbow is bent, the ulnar nerve can stretch and catch on the bony bump. When the ulnar nerve is compressed or entrapped, the nerve can tear and become inflamed, leading to cubital tunnel syndrome.

Signs and Symptoms of ulnar nerve entrapment (cubital tunnel syndrome)

In general, the signs and symptoms of cubital tunnel syndrome arise gradually, progressing to the point where the patient seeks medical attention. Left untreated, cubital tunnel syndrome can lead to permanent nerve damage in the hand. Commonly reported symptoms associated with cubital tunnel syndrome include:

  • Intermittent numbness, tingling, and pain to the little finger, ring finger, and the inside of the hand. These symptoms occur more frequently at night, and with elbow bending or prolonged resting on the elbow.
  • Aching pain to the inside of the elbow
  • Weakness in hand with diminished grip strength
  • Diminished sensation and fine motor control in the hand causing the person to drop objects or have difficulty in handling small objects.
  • Muscle wasting in the hand and permanent nerve damage, if left untreated.

Causes of ulnar nerve entrapment (cubital tunnel syndrome)

The common causes responsible for cubital tunnel syndrome, include:

  • Trauma
  • Repetitive motion
  • Frequent pressure on the elbow for extended periods
  • Medical conditions such as bone spurs, ganglion cysts or tumours in the cubital tunnel, leading to pressure and irritation of the ulnar nerve.

Diagnosis of ulnar nerve entrapment (cubital tunnel syndrome)

Your physician will perform the following:

  • Medical history
  • Physical examination

Your physician may order X-ray and electro diagnostic tests such as electromyography and nerve conduction studies. These tests can assist your doctor in determining how well the nerve is functioning and locate areas of muscle wasting and nerve compression.

Treatment of ulnar nerve entrapment (cubital tunnel syndrome)

Your physician will initially recommend conservative treatment options to treat the symptoms unless muscle wasting or nerve damage is present.

Conservative treatment options may include the following:

  • Avoid frequent bending of the elbow.
  • Avoid leaning on the elbow and applying pressure on it. Elbow pads may be worn to decrease pressure when working at a desk.
  • Wear a brace or splint at night while sleeping to keep the elbow in a straight position. You can also wrap the arm loosely with a towel and apply tape to hold it in place.
  • Avoid activities that tend to bring on the symptoms.
  • NSAIDs (non-steroidal anti-Inflammatory drugs) such as ibuprofen or aspirin may be ordered to reduce swelling.
  • Referral to OT (occupational therapy) for instruction in strengthening and stretching exercises may be recommended.

Surgical Treatment

If conservative treatment options fail to resolve the condition or if muscle wasting or severe nerve compression is present, your surgeon may recommend a surgical procedure to treat your condition.

The goal of cubital tunnel surgery is to reduce the pressure on the ulnar nerve by providing more space for the nerve to move freely and increase blood flow to promote healing of the ulnar nerve. There are different surgeries that can be performed to treat your condition, such as:

  • Medial epicondylectomy:This surgery involves removing the medial epicondyle, the bony bump on the inside of the elbow, enabling the ulnar nerve to glide smoothly when the elbow is flexed and straightened.
  • Ulnar nerve transposition: This surgery involves creating a new tunnel in front of the medial epicondyle and transposing (moving) the ulnar nerve to the new tunnel. Your surgeon will decide which options are best for you depending on your specific circumstances.

Your surgeon will decide which options are best for you depending on your specific circumstances.

Post-operative Care

After surgery, you will be given guidelines to follow depending on the type of repair performed and your surgeon’s preference. Common postoperative guidelines include:

  • A bulky dressing with a plaster splint is usually applied following surgery for 10-14 days.
  • Elevating the arm above heart level and moving the fingers are important to prevent swelling.
  • The arm dressing and sutures are removed after 10-14 days.
  • Elbow immobilisation for 3 weeks after surgery is usually indicated, longer depending on the repair performed.
  • Ice packs are applied to the surgical area to reduce swelling. Ice should be applied over a towel to the affected area for 20 minutes every hour. Keep the surgical incision clean and dry. Cover the area with plastic wrap when bathing or showering.
  • Occupational therapy will be ordered a few weeks after surgery for strengthening and stretching exercises to maximise the use of the hand and forearm

Risks and Complications

The majority of patients suffer no complications following cubital tunnel surgery; however, complications can occur following elbow surgery and include:

  • Infection
  • Nerve damage, causing permanent numbness around the elbow or forearm
  • Elbow instability
  • Elbow flexion contracture
  • Pain at the site of scar
  • Symptoms unresolved even after the surgery