There are multiple surgical procedures to address peripheral nerve injury. Some injuries can be repaired by re-connecting the ends of the damaged nerve (called primary or end-to-end nerve repair). If the nerve damage results in a gap between the ends of the nerve and they can’t be re-connected, bridging the gap with a nerve graft — similar to splicing a wire — might work.

What is a nerve graft?

A nerve graft is a piece of nerve tissue that serves as a bridge to fill a gap between the two ends of a damaged nerve. Nerve grafting surgery is sometimes called a nerve transplant because the graft is removed from one location and placed in another.

Types of Nerve Grafts

There are two types of nerve grafts, which depend on where the graft comes from:

• A nerve autograft is sourced from within your body. It is typically taken from a sensory nerve that provides sensation to an area of your skin where sensation is not vital.
• A nerve allograft is sourced from a cadaver. It is processed and sterilized to make sure it can be safely implanted and to remove the risk of rejection.

How does nerve grafting work?

A nerve graft provides a pathway for axons in the nerve to re-grow across the gap. Nerve autografts taken from your body contain support cells, called Schwann cells, that help with nerve regeneration.

Who can benefit from a nerve graft?

A surgeon uses specific criteria to evaluate whether a nerve graft is the right approach to nerve damage repair:

• When the injury happened. All methods of nerve repair, including nerve grafting, should be done in a timely manner. If too much time passes after an injury, a nerve graft may no longer be an option to restore function.
• Type of injury. Some injuries cause severe nerve damage that requires a surgeon to remove the damaged nerve tissue, which creates a gap. A nerve graft could be used to restore the injured nerve, but a clean, sharp nerve injury such as a cut with a sharp object can sometimes be repaired by re-connecting the ends of the nerve.
• The length of the gap. A nerve graft’s success largely depends on the length of the graft. Shorter grafts tend to provide better results than longer grafts. When the gap between the ends of an injured nerve is too long to be repaired with a graft, your surgeon may recommend other types of nerve repair, such as a nerve transfer. The repair method depends on many factors and there is no specific graft length that applies to all scenarios.

What types of conditions are treated with nerve graft surgery?

A nerve graft can be used to repair many types of peripheral nerve injuries. Common peripheral nerve conditions that may require nerve grafting include:

• Trauma to a portion of a nerve, such as stretch, crush or complex sharp injuries (e.g., propeller and saw injuries), and injuries that result in extensive scarring on the ends of the torn nerve. Brachial plexus injury is often treated with nerve grafting alone or in combination with other types of procedures, such as nerve transfers.
• Nerve tumors and cancers
• Facial paralysis

Which nerves can be used for harvesting a graft?

The surgeon considers several factors when determining which nerve to use as a donor for the graft. The nerve’s function is a major factor. The donor nerve typically supplies sensation to an area of skin where sensation is not critical. Nerve grafts are also sometimes taken from nonfunctioning nerve tissue below the injury. Common donor nerves include:

• Sural nerve in the back of the leg that provides sensation to parts of the lower leg and ankle
• Medial and lateral antebrachial cutaneous nerves in the arm that provide sensation to portions of the forearm

What happens during a nerve graft surgery?

The details of the nerve grafting procedure vary depending on whether you are getting an allograft or an autograft. With an autograft (your own donor nerve), the surgeon needs to harvest a piece of the nerve before transplanting it to the new location. This step usually involves:

• Placing you under general anesthesia so you don’t feel pain and discomfort
• Marking the path of the donor nerve on your leg or arm, depending on which nerve is chosen
• Making several small incisions along the path of the nerve to allow the surgeon to gently pull and retrieve it
• Removing a piece of the donor nerve of necessary length
• Placing the ends of the donor nerve into nearby muscles to help prevent painful neuroma/scar from forming

Once the nerve graft is ready, the surgeon makes an incision close to the injured nerve. Before attaching the graft, the surgeon may need to remove injured or scarred nerve tissue, which will leave a gap in the nerve. The surgeon then measures and cuts an appropriate length of the graft and attaches it to both ends of the injured nerve to bridge the gap. Depending on the graft’s diameter, the surgeon may use sutures (stitches) to attach larger nerves or a special glue to connect smaller nerves.

Recovery After Nerve Graft Surgery

Most people can go home the same day or one day after nerve graft surgery. Before you leave, the surgeon may use a splint or sling, which you may need to wear for two or three weeks, to immobilize the affected limb.

It may take many months after a nerve graft surgery to start regaining movement and sensation in the part of the body affected by the injury. The nerve graft provides a pathway for nerve regeneration, and nerve fibers grow about an inch per month, so it may take several months for the fibers to reach the muscle and skin that lost nerve supply. During this time, your surgeon will likely prescribe physical and/or occupational therapy to help prevent stiffness and strengthen the muscles that are currently working. As the nerve fibers reach the muscle that lost the nerve supply due to the injury, you may need more physical or occupational therapy to strengthen that muscle as it begins to recover.

Your age, the type and location of the injury, how long ago the injury occurred, skill of the surgeon, your participation in therapy and many other factors play a role in how fast you recover function after a nerve graft surgery.

Risks and Complications of Nerve Graft Surgery

Nerve graft surgery carries the same risks as all types of surgery, including the risk of infection, scarring and wound healing complications. It is also possible that you will not achieve the recovery of function you expect.

Donor Nerve Symptoms

When a nerve graft is taken from your body, you may experience numbness in the area that the sensory donor nerve used to supply. Because the nerves selected for grafting do not perform crucial functions, most patients do not find the numbness to be a big concern. Some patients partially regain sensation in the numb area over time, as the surrounding nerve fibers grow into it. Less commonly, patients have pain in the area where the nerve graft was taken.