Serious injuries to the muscles and tendons may result in permanent loss of movement. John R. Barbour, MD, FACS, is a triple board-certified plastic and reconstructive surgeon who offers tendon transfer and function reanimation procedures. The residents of the Washington, DC, area, including Fairfax, Arlington, Alexandria and surrounding communities in Virginia, rely on Dr. Barbour for the procedure because he is a fellowship trained hand and peripheral nerve specialist who has an exceptional reputation for performing tendon transfer and functional reanimation.
When all muscles in a group are denervated or destroyed, motion is lost. When available, tendons can be transferred (tendon transfer) from an adjacent muscle compartment to restore lost function. When local muscles are also affected, or when major soft tissue or major nerve crush/avulsion injury is present, a functional muscle transfer (functional reanimation) can be utilized to overcome the barriers presented by extensive injury.
Our approach to muscle transplantation to restore function is based on the work of the other major microsurgical centers in the world as well as the evolution of our clinical experience and research. The goal of functional reanimation is to restore active motion and satisfy a patient’s particular functional need. To be successful, this requires that certain criteria be met:
- Supple/mobile joints
- Adequate hand sensibility
- Understands the concepts involved and agrees to participate in rehab
The functional muscle can be transplanted early after non-traumatic muscle deficits, such as after Volkmann’s ischemic contracture and compartmental surgical resection for malignant tumors. In these situations, the zone of injury is limited. However, functional muscle transplantation must be staged in situations where patients have sustained traumatic loss. These include muscle compartment destruction after limb amputation, mechanical crush/avulsion, and major nerve avulsion.
Several muscles potentially meet the criteria for FMMT. The gracilis muscle (in the thigh) is most often used as a FMMT. Its size, length, and shape most closely approximates that of the muscles which provide flexion and extension in the hand, flexion at the elbow, as well as, dorsiflexion at the ankle.
Examples of Functional reanimation
The facial nerve controls all facial expressions. This includes the ability to eat without food falling from the corner of the mouth, show emotions such as demonstrate a normal smile, and maintain normal vision by closing the eye. Injury to the Facial nerve can occur after surgeries to remove tumors, after some illnesses such as Bell’s palsy, from birth trauma or congenital deficits, or from trauma to the area near the cheek. Some facial nerve injuries, if recognized early, can be repaired by finding the cut nerve ends and putting them together. Occasionally, the space between the nerve endings requires using nerve grafts from another part of the body to restore the lost function.
Nerve injuries over several months in age are more difficult to repair. Dr. Barbour occasionally will perform what is called a “functional muscle transfer” in several stages to allow a new muscle to move the corner of the mouth. In order to restore a smile, both new nerves and a new muscle from the leg must be transferred to the cheek in a delicate microsurgical procedure.
Major Soft Tissue Loss
Muscle compartments can be mechanically lost secondary to traumatic crush/avulsion, Volkmann’s ischemic contracture, or after surgical resection for malignant tumors. When the wounds are healed, a functional muscle can be transplanted to restore active motion across the joints of the upper and lower extremities.
Major Nerve Injury
Major peripheral nerve injury will result in loss of synergistic muscle function. The first approach is primary nerve repair or nerve grafting. When this is not possible, or repair has failed and resultant muscle atrophy has occurred, a functional muscle transfer can be attempted. Common examples include brachial plexus or common peroneal nerve injury. A functional gracilis transfer to the anterior compartment of the leg has restored foot dorsiflexion and the ability to walk without dependence on ankle splints in a selected group of patients. Patients with devastating injuries to their upper and lower extremities should be evaluated by a reconstructive microsurgeon as well as a therapist or prosthetist. In selected patients, functional muscle transplants can restore function and allow patients to return to their daily activities.
Foot Drop Nerve Transfers
Peripheral nerve surgeons can treat foot drop: paralysis of the muscles below the knee that lift the front part of the foot, resulting in a foot that “hangs” at the ankle. A person who has foot drop may have difficulty walking and need to wear a brace on the leg. Possible causes of foot drop include lumbar disc herniation, damage to the peroneal nerve (usually near the knee) or damage to the nerve above the knee. A foot drop can begin after an injury to the back or leg, an operation on the knee, or even activities such as squatting for prolonged periods of time or crossing legs.
When the weakness is due to compression of the peroneal nerve, a simple operation can be performed. The peroneal nerve runs around the neck of bone on the outside of the leg (fibula) just below the knee. It then runs under a muscle that frequently has a tight fascial edge (the peroneus longus). At the point where the nerve runs under this muscle, this tight spot can be released and pressure eliminated.
Many times, this is all that is required to restore function to the foot. At times, these procedures will not be sufficient to restore the function of the foot. In such cases, nerve transfers can sometimes be used. This procedure involves taking nerves with less important roles — or branches of a nerve that perform redundant functions- and transferring them to restore function in a more crucial nerve that has been severely damaged.
A nerve transfer for correcting a foot drop may involve taking branches of the tibial nerve, which supplies muscles that push the foot down, and transferring them to nerves that supply muscles involved in pulling the foot up. Either the branches of the tibial nerve that innervate the muscles that flex the toes or those that contribute to flexing the calf muscles may be used as donor nerves. After this procedure, patients will still be able to push the foot down. However, as they regain function from the nerve transfer, they also will be trained to use these muscles to pull the foot up.
The brain then learns this process, and the patient is able to pull the foot up simply by thinking about pulling the foot up. This can be a difficult transfer to re-educate and may require a physical therapist helps patients learn this technique. Recovery of function after nerve transfer is a long process. Patients generally see small signs of recovery three to six months after the operation, but in most cases, return of movement takes six to 12 months.