Median Nerve Injury — Symptoms, Causes & Treatment

The median nerve is one of the major nerves in the arm and runs from the forearm to the hand. It controls the movement and sensation of the thumb, index finger, middle finger, and ring finger. A median nerve injury occurs when the nerve is damaged or compressed, causing a range of symptoms depending on the severity of the injury.

Median nerve injury occurs due to many causes, a few of which are mentioned below:

• Trauma or injury to the wrist or forearm.
• Repetitive motion injuries such as carpal tunnel syndrome.
• Nerve compression due to swelling or inflammation.
• Fractures or dislocations of the wrist or elbow.
• Medical conditions like diabetic neuropathy.
• Tumors, etc.

The symptoms of median nerve injury vary depending on the severity of the condition, a few symptoms of median nerve injury can include:

• Weakness in the hand and wrist.
• Numbness or tingling in the fingers.
• Pain or discomfort in the wrist or forearm.
• Difficulty grasping or holding objects.
• Loss of coordination in the fingers.
• Muscle atrophy (wasting) in the hand, etc.

Pathology:
Compression, repetitive stress, or trauma to the median nerve can result in nerve damage, which can lead to loss of sensation and motor function in the hand and fingers. Certain medical conditions, such as diabetes and alcoholism, can cause damage to the nerves, including the median nerve. This can result in neuropathy, which can cause a range of symptoms, including pain, numbness, and weakness. Rarely, tumors can develop along the course of the median nerve and cause compression and damage to the nerve, leading to symptoms such as pain, numbness, and weakness.

Physical examination: The diagnosis of median nerve injury typically involves a thorough medical history and physical examination, which may include a review of symptoms and a comprehensive evaluation of the affected hand and wrist. The physician may also conduct various tests to help confirm the diagnosis, including:
Tinel's sign: The physician taps on the affected area to see if there is a tingling or electric shock-like sensation in the fingers. This is a positive sign of median nerve injury.
Phalen's maneuver: The patient is asked to flex the wrist for a minute to see if there is any numbness or tingling in the fingers. This test is positive if it produces the symptoms associated with median nerve injury.

Electromyography (EMG):
This test measures the electrical activity of muscles and nerves in the arm and hand to determine if there is any damage to the median nerve.

Nerve conduction studies (NCS):
This test measures the speed and strength of electrical signals that travel along the median nerve to confirm the location and severity of the nerve injury.

Imaging studies:
X-rays, ultrasound, or MRI may be used to identify any structural abnormalities or injuries to bones, muscles, or other soft tissues that may be contributing to the nerve injury. Once the diagnosis of median nerve injury is confirmed, the physician will develop a treatment plan tailored to the severity and cause of the injury.

MEDICATION: Nonsteroidal anti-inflammatory drugs (NSAIDs), Corticosteroids, Antidepressants, Anticonvulsants, Muscle relaxants, etc.

NOTE: Medication should not be taken without the doctor’s prescription.

Surgery :
Surgery may be necessary for severe cases of median nerve injury that do not respond to conservative treatments, such as physical therapy and rest. The type of surgery performed depends on the location and severity of the injury. Here are some surgical options for median nerve injury:

Carpal Tunnel Release: This is a common surgery for carpal tunnel syndrome, which is caused by compression of the median nerve at the wrist. During the procedure, the surgeon cuts the ligament that is compressing the nerve to relieve pressure and improve function.

Nerve Grafting: In cases where the median nerve is completely severed or damaged beyond repair, the surgeon may use a nerve graft to bridge the gap between the two ends of the damaged nerve. The graft is taken from another nerve in the body and is used to restore the function of the median nerve.

Nerve Transfer: This procedure involves transferring a healthy nerve from another part of the body to the damaged area to restore function. In cases of median nerve injury, the surgeon may transfer a nerve from the ulnar nerve to the median nerve to restore hand and finger movement.

Tendon Transfer: In severe cases of median nerve injury, the surgeon may perform a tendon transfer to restore hand and finger movement. During the procedure, a tendon from another part of the body is moved to the hand and attached to the muscles that control hand and finger movement.

Cryotherapy:
Cryotherapy or cold therapy helps reduce inflammation and swelling in the affected area. The physiotherapist may use a cold towel or an ice pack to apply to the affected area.

Thermotherapy:
Thermotherapy or heat therapy helps to improve circulation and reduce muscle tension in the affected area. The physiotherapist may use a warm towel or a hot pack to apply heat to the affected area.

Transcutaneous Electrical Nerve Stimulation (TENS):
This involves the use of low-frequency electrical stimulation to reduce pain and inflammation. The TENS unit is connected to adhesive electrodes placed on the skin around the affected area. The electrical stimulation helps to block pain signals from reaching the brain, providing pain relief.

Electrical Muscle Stimulation (EMS):
This involves the use of electrical stimulation to activate the muscles around the affected area. The EMS unit is connected to adhesive electrodes placed on the skin over the affected muscles. The electrical stimulation helps to improve muscle strength and function, which is particularly useful in cases where the median nerve injury has caused muscle weakness or wasting.

Ultrasound Therapy:
This involves the use of high-frequency sound waves to promote healing and reduce inflammation. The ultrasound device is applied to the skin over the affected area, and the sound waves penetrate the tissues to promote circulation and accelerate the healing process.

Iontophoresis:
This involves the use of a small electrical current to deliver medication directly to the affected area. The medication is applied to a patch placed on the skin over the affected area. The electrical current helps to drive the medication into the tissues, providing localized pain relief and reducing inflammation.

Range of motion exercises:
These exercises aim to improve the flexibility and range of motion in the affected hand and wrist. Examples include wrist flexion and extension, finger flexion and extension, and forearm supination and pronation.

Strengthening exercises:
These exercises aim to improve the strength and function of the muscles in the hand and wrist. Examples include grip strengthening exercises, wrist curls, and forearm pronation and supination exercises.

Neural gliding exercises:
These exercises aim to improve the mobility of the median nerve and reduce tension or adhesions that may be limiting its function. Examples include nerve gliding exercises, median nerve flossing, and carpal tunnel gliding exercises.

Sensory re-education exercises:
These exercises aim to improve sensory function and retrain the brain to interpret sensory input from the affected hand and wrist. Examples include texture recognition exercises, two-point discrimination exercises, and vibration therapy.

The patient should be educated about the recovery time for a median nerve injury, as it can vary depending on the severity of the injury and the treatment received. Patients may need to undergo rehabilitation and work with a physiotherapist to regain strength and function in the affected hand and wrist. Patients with a history of median nerve injury or who engage in activities that put them at risk for injury should take steps to prevent future injuries. This may include taking frequent breaks, using ergonomic equipment, and modifying activities to reduce stress on the hands and wrists.