Nerves are fragile and can be damaged by pressure, stretching, or cutting. Nerve Injuries can stop signals to and from the brain, causing muscles not to work properly, and a loss of feeling in the injured area.
There are many nerves that run between the shoulder and the fingertips in the area of the body known as the upper extremity. These nerves are responsible for carrying messages from the brain to parts along the arm for movement, feeling and reflexes. The nerves in the upper extremity leave the central nervous system through several areas in the neck, and form a complex structure called the brachial plexus. The nerves are larger in diameter near the neck, and eventually divide to form smaller branches in the upper arm, forearm and hand.
Injuries to the upper extremity occasionally cause trauma to nerves, which can interfere with the various functions of the arm and hand. Occasionally, the nerve is bruised, and may heal on its own in time. However, if a nerve is cut or crushed, it may need surgical treatment in order to help improve or restore function to the hand or arm. Sometimes, certain illnesses can affect nerves and cause similar symptoms in the upper extremity.
Symptoms of Nerve Injury
Symptoms generally occur following an injury to the neck, shoulder, arm or hand. Sometimes, symptoms may occur after something as simple as laying on the arm for too long. Other injuries may occur after a crush or sharp cut along any part of the nerve. Common symptoms of nerve injury include:
- Loss of sensation in the upper arm, forearm, and/or hand. Each nerve supplies different areas of sensation in the upper extremity. The pattern of numbness can help guide the surgeon to the specific injured nerve(s).
- Loss of function in the upper arm, forearm, and/or hand. The muscles in the upper extremity are supplied by different nerves. The muscles that do not function properly help guide the surgeon to the specific injured nerve(s).
- Wrist drop or inability to extend the wrist
- Decreased muscle tone in the upper arm, forearm, and/or hand
- Changes in sweating patterns of the upper arm, forearm, and/or hand
Pressure or stretching injuries can cause fibers within the nerve to break. This may interfere with the nerve’s ability to send or receive signals, without damaging the cover.
When a nerve is cut, both the nerve and the insulation are severed. Sometimes, the fibers inside the nerve break while the insulation remains intact and healthy. If the insulation has not been cut, the end of the fiber farthest from the brain dies. The end that is closest to the brain does not die. After some time, it may begin to heal. New fibers may grow beneath the intact insulating tissue until it reaches a muscle or sensory receptor.
If both the nerve and insulation have been severed and the nerve is not fixed, the growing nerve fibers may form a painful nerve scar, or neuroma.
Diagnosis of Nerve Injury
Depending on the complexity of the condition, patients may visit with more than one physician, surgeon, therapist or physician assistant. Consultations usually last 1-2 hours. During this important visit, patients should expect to:
- Undergo a physical examination and provide a complete medical history, including information about previous surgical procedures, past and present medical conditions, and any current medications or herbal supplements.
- Discuss possible options for treatment of the condition, including whether surgery is recommended. If surgery is recommended, patients will discuss the surgical procedure in detail, including the possible risks and complications of the procedure, recovery and rehabilitation period, and the probable outcome in terms of function and appearance.
In addition to an initial consultation appointment, additional diagnostic tests may be ordered. These include:
- Electrodiagnostic nerve studies (EMG)
- X-ray: Images used to determine if fractures are present
- CT Scan, MRI, or ultrasound (US) for more detailed imaging
How Nerve Injuries are treated?
We offer the latest treatment options available for patients with nerve injuries. Surgical treatment is decided on a case-by-case basis, and depends on the location, duration, and type of nerve injury.
Surgery. The goal of surgery is to improve function of the affected area in the upper extremity.
If the nerve is thought to be repairable, surgical treatment may consist of Nerve decompression, Nerve repair, Nerve graft.
If nerve repair is not an option, a tendon transfer may be recommended. Tendon transfers borrow extra tendons from other parts of the hand or forearm to perform a function that is lost due to the nerve injury. The tendon chosen so the patient does not have loss of function with use of the donor tendon.
Hand Therapy and Rehabilitation
Hand therapy is provided on site at the University of Michigan’s Hand Program by our team of occupational and physical therapists under the direction of a trained hand therapist. Referrals to local providers can be arranged closer to home as a more convenient option for patients.
The ultimate goal of therapy and rehabilitation is the restoration and optimization of hand function, renewed independence and improved overall quality of life. We offer treatment plans that are tailored to fit each patient’s condition, living and work requirements:
- Non-surgical option: For patients who do not require surgery but would benefit from therapy.
- Post-operative rehabilitation: To help patients as they recover from surgical procedures.