The peripheral nervous system is a network of 43 pairs of motor and sensory nerves that connect the brain and spinal cord (the central nervous system) to the entire human body.

These nerves control the functions of sensation, movement and motor coordination. They are fragile and can be damaged easily. When one of these nerves suffers serious injury or trauma, surgical treatment may be called for.

What causes peripheral nerve injury?

Injury to the peripheral nerve network can happen through:

• Laceration (a cut or tear in the nerve tissue)

• Severe bruising (contusion)

• Gunshot wounds

• Stretching (traction)

• Drug injection injury

• Electrical injury

Peripheral Nerve Injury Symptoms

People with traumatic nerve damage can experience severe, unrelenting pain, burning sensation, tingling or total loss of sensation in the part of the body affected by the damaged nerve.

Peripheral Nerve Injury Classification

A classification system called the Sunderland classification system defines five different degrees of peripheral nerve injury:

1. First degree: A reversible local conduction block at the site of the injury. This injury does not require surgical intervention and usually will recover within a matter of hours to a few weeks.

2. Second degree: There is a loss of continuity of the axons (the “electrical wires”) within the nerve. If this kind of injury can be confirmed through pre-operative nerve testing, surgical intervention is usually not required.

3. Third degree: There is damage to the axons and their supporting structures within the nerve. In this case, recovery is difficult to predict. Nerve conduction studies performed during surgery are often able to help indicate outcome and need for simple cleaning of the nerve (neurolysis) or a more extensive repair with grafting.

4. Fourth degree: In this case, there is damage to the axons and the surrounding tissues sufficient to create scarring that prevents nerve regeneration. Electrical testing performed during surgery confirms that no electrical energy can be passed along the neural pathways in this injured nerve. Surgical intervention with nerve grafting is necessary to repair the injury.

5. Fifth degree: These injuries are usually found in laceration or severe stretch injuries. The nerve is divided into two. The only way to repair a fifth-degree injury is through surgery.

Spinal Accessory Nerve Injury

One particular type of peripheral nerve damage is spinal accessory nerve injury. The spinal accessory nerve is the 11th of 12 cranial nerves, which originate in the brain. It allows two sets of muscles in the neck to function: the sternomastoid muscles, which allow the head to tilt and rotate, and the trapezius muscles, which allow for several motions, such as shrugging the shoulder or moving the shoulder blades.

The spinal accessory nerve can be damaged during trauma or even during surgery when surgeons are operating on lymph nodes or on the jugular vein in the neck.

The symptoms are shoulder pain, outward “winging” of the shoulder blades, and weakness or atrophy of the trapezius muscle.

Prompt diagnosis and treatment provides the best chance for recovery from this injury. Doctors are likely to recommend physical therapy for mild spinal accessory nerve injury. Surgery may be needed for more severe injuries, and may involve nerve grafting, nerve regeneration or tendon or muscle transfer.

Diagnosis of Peripheral Nerve Injury

In order to fully determine the extent of the damage to the nerve, the doctor may order an electrical conduction test to determine the passage of electrical currents through the nerves. Two of these tests are electromyography and nerve conduction velocity. These tests are sometimes done during actual surgery while the patient is sedated.
The doctor may also order any of the following imaging techniques:

• CT scan

• MRI

• MRI neurograph

Peripheral Nerve Injury Treatment

Depending on the location and degree of the nerve damage, the doctor may prescribe different courses of therapy.
For mild nerve injuries, the following non-surgical treatments may be part of the plan:

• Acupuncture

• Massage therapy

• Medication

• Orthotics

• Physical therapy and rehabilitation

• Weight loss

More severe injuries may require peripheral nerve surgery, which is performed by a neurosurgeon. These surgical procedures can be highly complicated and this is why it is essential to select an experienced surgeon and team for peripheral nerve operations.

Procedures include:

• Brachial plexus surgery

• Carpal tunnel surgery

• DREZ procedure

• Free muscle transfer

• Nerve repair or nerve graft

• Nerve entrapment surgery

• Nerve sheath tumor surgery

• Nerve transfer surgery

• Nerve transplant surgery

• Open decompression surgery

• Sensory nerve surgery (for meralgia paresthetica)

• Thoracic outlet syndrome surgery

An Innovative Approach to Nerve Repair | Santi’s Story

Watch on YouTube -

Santi's sciatic nerve was severed in a boating accident, paralyzing his right leg. He and his family traveled from Texas to Baltimore, where they met with neurosurgeon Allan Belzberg and orthopaedic trauma surgeon Greg Osgood. Together, the two surgeons collaborated to offer a novel way to repair Santi's leg and get him back to the water.