Cubital Tunnel Syndrome

Introduction

Cubital tunnel syndrome refers to the compression of the ulnar nerve within the elbow region, specifically at the medial epicondyle. This vital nerve traverses a confined space known as the cubital tunnel, where it’s susceptible to injury and compression. The familiar “funny bone” sensation occurs when the ulnar nerve is compressed, primarily affecting the little finger and the ring finger.

Understanding Ulnar Nerve Location and Compression Points

In the arm, there are three principal nerves: the median, the ulnar, and the radial. The ulnar nerve extends from the neck, down the arm, through the forearm, and into the hand. It serves to provide sensation to the small finger and part of the ring finger while controlling fine finger movements. Compression of the ulnar nerve can occur at the elbow, higher up in the arm, or at the wrist within Guyon’s canal.

Who's at Risk for Cubital Tunnel Syndrome?

Cubital tunnel syndrome is typically triggered by factors like increased pressure on the ulnar nerve within the elbow. Risk factors include pressure from casts or splints, arthritis of the joint, prolonged elbow bending, bone spurs, cysts near the elbow joint, and elbow joint fractures or dislocations.

Causes of Ulnar Nerve Compression

Ulnar nerve compression can be caused by leaning on an armrest, nerve snapping over the medial epicondyle during elbow movement, or prolonged bending of the elbow (as seen when working on a computer or during sleep). Repeated and extended compression, snapping, and overstretching can lead to nerve inflammation, pain, and nerve damage .

Distinguishing Cubital Tunnel Syndrome from Carpal Tunnel Syndrome

Cubital tunnel syndrome primarily affects the little and ring fingers, while carpal tunnel syndrome affects the thumb, index, and middle fingers.

Symptoms of Cubital Tunnel Syndrome

Symptoms start gradually and may include inner elbow and forearm pain, intermittent numbness and tingling in the hand, especially in the little finger and ring finger, and difficulties in finger movement when they fall asleep.

As the condition progresses, symptoms become more constant with:

• Weakness in the hand, curling of the little and ring fingers.
• increased pain, and diminished ability to perform intricate tasks.
• Severe cases may exhibit muscle atrophy or fingertip ulcers.

Diagnosis of Cubital Tunnel Syndrome

Diagnosis often involves a clinical assessment that includes history, physical examination, and occupational/lifestyle details. Clinical signs may include weak forearm and hand muscles, decreased sensation in the little and ring fingers, and a positive Tinel’s sign.

Few investigations are done to confirm the diagnosis-

• a) Nerve Conduction Velocities (NCV) and Electro-Myographic Studies (EMG) of the affected hand are quite diagnostic for cubital tunnel syndrome
• b) An MRI of the elbow is done in a few cases if any tumor or mass is suspected.
• c) Blood tests for diabetes or thyroid disease .
• d) X-rays to check for bone spurs, arthritis, and places where bone might compress the ulnar nerve.

Treatment Options

Cubital tunnel syndrome can be managed through non-surgical or surgical means, depending on the severity.

Non-Surgical Treatment

Non-surgical treatment focuses on less severe cases and involves:

• Wearing a wrist splint at night to maintain elbow alignment.
• Taking anti-inflammatory drugs.
• Performing nerve gliding exercises to facilitate ulnar nerve movement.
• Modifying lifestyle and work habits to alleviate symptoms.

Surgical Treatment

Surgery is recommended for more severe cases or when non-surgical methods fail to alleviate symptoms. Surgical procedures involve cubital tunnel release and anterior transposition of the ulnar nerve to reduce pressure on the nerve.

Recovery after Surgery

Post-surgery, finger movements will be initiated as anesthesia effects wear off. Recovery involves a period of discomfort, immobilization of the elbow, suture removal, and crucial post-operative physiotherapy to maximize outcomes.

• Finger movements are started once the effect of the brachial plexus block is gone or when the patient is out from anesthesia.
• You might be in brief discomfort for about 24 to 72 hours after surgery.
• Immobilization of the elbow in the flexion position is done till sutures are removed.
• Sutures are removed after a period of 10-12 days.
• Physiotherapy post-operative is most important for the hand, wrist, and fingers.
• The prognosis is good if muscle atrophy has not started.
• You might be unable to do heavier activities with the affected hand for about four to six weeks

Late Cases of Cubital Tunnel Syndrome

In advanced cases with ulnar nerve palsy due to prolonged compression, tendon transfers may be necessary to strengthen weakened hand functions.

• Permanent curling of little and ring finger (inability to extend or straighten fingers at the middle and distal finger joints) and
• Loss of fine movements of the hand with complete loss of sensation over the little and the ring finger. (ULNAR CLAW HAND).

Tendon Transfer Procedure

Tendon transfers involve re-routing tendons from the forearm and hand to improve finger extension, allowing for meaningful finger movement and thumb pinch. This surgical procedure is usually performed under anesthesia, followed by immobilization and rehabilitation.

• The surgery is usually done under brachial block or general anesthesia and a splint or slab is given for immobilization in the post-operative period.
• The patient is usually discharged on the second day after the surgery. Sutures are removed 14 days after surgery.
• Splint is removed 3 to 4 weeks after the surgery and gradual training of the transferred muscles or tendons is started so that they regain their newly assigned function.