Traumatic Nerve Injury

Nerves are the “wires” that carry messages between the brain and the rest of body. “Sensory nerves” carry messages about “sensation” — pain, temperature, vibration, and pressure. “Motor nerves” carry messages to muscles to instruct them to move. Nerves contain bundles of smaller “fascicles” and may contain both sensory and motor nerves. Injury to nerves can occur from a variety of mechanisms including penetrating trauma with sharp objects, gunshot wounds, high energy trauma such as motorcycle accidents or falls from ladders, surgical (iatrogenic) injuries, direct pressure, or stretching. Nerves in the arm, hand, and fingers (upper extremity), that may be injured include digital nerves in the fingers, median nerve, ulnar nerve, radial nerve, musculocutaneous nerve, axillary nerve, and other sensory nerves in the arm and forearm. There can also be injury to the brachial plexus, which is the complex network of nerves that emerge from the neck and travel into the hand and arm. Nerves in thigh, letg, and foot (lower extremity), that may be injured include the sciatic nerve, tibial nerve, common peroneal nerve, deep peroneal nerve, superficial peroneal nerve, saphenous nerve, sural nerve, and other sensory nerves. Nerve injuries can have a significant impact on daily life and overall function. Prompt diagnosis and appropriate treatment of nerve injuries by a specialist often are important for achieving the best possible outcome.

Diagnosis of a nerve injury benefits from evaluation by a specialist in peripheral nerve surgery. When a nerve is injured, there can be associated areas of weakness, numbness, and/or pain. This is often associated with a painful burning or tingling sensation known as “neuropathic pain”, and there may be a focal area of exquisite pain that when tapped causes shooting electrical sensations known as a “Tinel’s sign”. This will be assessed during a physical exam. Additional studies that may be needed for evaluation include electrodiagnostic testing to assess activity of the nerve with nerve conduction studies (NCS) and electromyography (EMG), ultrasound, or MRI. Monitoring for nerve recovery may require several evaluations over a period of weeks or months.

Treatment often depends on how and when the nerve was injured. Milder injuries may gradually recover over time, which may take several months or longer. When a nerve has been completely cut or when it is severely injured, surgery typically is needed to repair the nerve. The two ends of the injured nerve are identified, and any damaged nerve is removed. If possible, the two nerve ends are then repaired to one another. However, it often is necessary to use a nerve graft. This typically is performed either with donor nerve harvested from another part of the body or a frozen donor “nerve allograft”. The nerve repair typically is performed with an operating microscope and suture finer than a human hair.

In some situations, the nerve cannot be be repaired or reconstructed. To restore lost function due to the nerve injury, additional treatment strategies including nerve transfer or tendon transfer may be used.

If too much time has passed after the nerve injury, then the “neuromuscular junctions” (NMJ), where the nerve enters into the muscle, may degenerate. If this occurs, nerve function cannot return to the affected muscle, necessitating alternative reconstructive strategies such as tendon transfers. For this reason, it is important to seek treatment as soon as possible after a nerve injury.

For more information on specific nerve injuries that may benefit from treatment, please see the following pages:
Brachial plexus injury
Neuroma
Post-mastectomy pain syndrome (PMPS)
Chronic post-surgical pain
Phantom limb pain or neuroma pain after amputation

If a nerve is repaired surgically, it will gradually begin to heal. Recovery with new nerve growth usually proceeds at one millimeter per day or one inch per month, although this is dependent on other factors such as the type of injury, age of the patient, and associated medical conditions. While the nerve is healing, there may be an uncomfortable “pins and needles” sensation. Final recovery may take several months or longer depending on the distance required for nerve growth. The amount of recovered sensory or motor function depends on variety of factors, including the specific nerve injured and the distance of the injured nerve to its targets.

Be sure to see an experienced surgeon to treat this condition. Our fellowship-trained specialists at The Buncke Clinic in San Francisco treat patients with traumatic nerve injuries from across the Bay Area and Northern California. Contact us to schedule a consultation.

Below are links for third party resources

American Society for Surgery of the Hand

American Academy of Orthopaedic Surgeons