Nerve Injury

Injury to the peripheral nerves can occur through a variety of trauma. Common causes of nerve injuries include:

• Laceration
• Focal contusion (gunshot wounds)
• Stretch/traction injury
• Compression
• Drug injection injury
• Electrical injury

Clinical Assessment
Your doctor will need to determine the exact location and severity of the nerve injury. A classification system called the Sunderland Classification system divides nerve injuries into five parts. These include:

1. First-degree injury: 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 weeks.
2. Second-degree injury: There is a loss of continuity of the axons or 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 injury: There is damage to the axons and their supporting structures within the nerve. In this case, recovery is variable. Intra-operative nerve conduction studies are often able to help predict outcome and need for simple cleaning of the nerve (neurolysis) or a more extensive repair with grafting.
4. Fourth-degree injury: In this case, there is damage to the axons and the surrounding tissues sufficient to create scarring that prevents nerve regeneration. Intra-operative electrical testing confirms that no sign of electrical energy being passed along the neural pathways in this injured nerve. Surgical intervention with nerve grafting is necessary to repair the damage.
5. Fifth-degree injury: These injuries are usually found in laceration or severe stretch injuries. The only way to repair a fifth-degree injury is through surgery.

Testing
In order to fully determine the extent of the damage to the nerve, your doctor will order an EMG, an electrical conduction test to determine the passage of electrical currents through the nerves. These tests are sometimes done during actual surgery while the patient is sedated.

Your doctor may also order any of the following imaging techniques:

• CT scan
• MRI
• MRI Neurography

Surgical Repair
The goal of surgical repair is to repair the nerves so that function is restored to the area. Depending on the type and severity of the injury, your doctor will discuss different methods of nerve repair and create a treatment plan that is appropriate for you.