Overview
The three primary nerves in the hand are the radial, median and ulnar. When one or all of these are damaged or destroyed, paralysis and loss of feeling – known as palsy – can develop. Some palsies also create uncontrollable movement. Because each nerve serves a different part of the hand, the injury or condition will result in a specific region of palsy.
Palsies of the hand nerves can be so severe that it’s difficult or impossible to perform acts of daily living. Hand surgeons can restore muscle functions via tendon transfers, in which healthy tissue is transferred from another part of the body to assume the duties of the paralyzed tissue. The patient’s own muscle and tendon can be used or the tissues can come from a donor.
More than three dozen muscles move joints below the elbow. Each muscle performs a different function, but their anatomies are similar. Muscles are attached to bones at opposite ends of joints. When muscles contract, the joint opens and closes. The fiber that attaches a muscle to a bone is a tendon. The muscle’s starting point is the origin (also called the attachment). The muscle’s opposite end is the insertion. The muscle’s middle is called its belly.
Essentially, a tendon transfer diverts a muscle so it can move a joint that otherwise doesn’t work because of nerve damage. When performed by expert hand surgeons and in patients whose injuries are most likely to respond to the surgery, the outcome of tendon transfer surgery is generally very good.
Procedural Details
Before this operation is considered, the hand surgeon assesses whether the tendon to be transferred can be moved from its original locale without adversely impacting other necessary functions. Often muscle function somewhat overlaps (redundancy), which allows a muscle/tendon to be moved without significantly diminishing its original function.
The surgeon also determines if the selected muscle is strong enough for its new job and if it can produce a movement in its new location similar to that of its previous location. The surgeon will ensure that the muscle can reach its new destination without a significant change of direction, without going through scar or other thick tissue, and so that it doesn’t cross bare bone. The surgeon also determines whether the muscle’s new joint location is free of injuries and isn’t stiff or frozen.
Tendon transfer surgery leaves the muscle’s origin in place, along with its blood and nerve supply. The far end of the muscle (the insertion) is detached from its original location. The muscle belly and insertion are rerouted and sutured to a new point. It can be attached to a different bone or set into another tendon.
Considerations
After an injury in which a nerve is damaged, the surgeon might wait a few weeks to determine whether the nerves can or will self-repair. If surgery is performed to try to repair the injured nerve, time also is needed afterward to determine whether the outcome was successful. Tendon transfers usually are performed only in instances in which nerve recovery does not occur after injury or initial nerve surgery, or is not expected to occur. These situations include:
- Irreparable nerve damage: Injuries that penetrate the arm or hand can cut and permanently damage the radial, median or ulnar nerve.
- Loss of function due to trauma or disease: A wrist fracture can damage the nerves that control hand function. Rheumatoid arthritis can also cause tendon rupture.
- Progressive neurological disorders: Patients who have sustained a stroke or who suffer a neurologic disease also may be candidates for tendon transfer surgery, but the procedure is done less often in these cases because of the degenerative nature of the neurologic disease. Hand function might not be restored in stroke patients despite tendon transfer surgery.
Effectiveness
When performed by expert hand surgeons and in patients whose injuries are most likely to respond to the surgery, the outcome of tendon transfer surgery is generally very good.
Radial: Reconstructive surgery to address radial nerve palsies is often successful in well-selected patients and when performed by skilled hand surgeons. Most patients are able to resume performing activities of daily life. Many patients return to their jobs after surgery and the appropriate rehabilitation period.
Median: A positive outcome is highly dependent on the following factors:
- the number of hand functions to be restored
- the number of tendons to be transferred
- the strength of the selected muscles and tendons
- the new courses of the transferred tissues
Your surgeon will consider the weight of each factor in working with you to determine if tendon transfer surgery is the best course of action to correct median nerve palsy.
Ulnar: Well-functioning joints are an important consideration in tendon transfer surgery. Tendon transfers to correct a claw hand tend to work best in younger patients who, generally speaking, have fewer joint problems and less joint stiffness compared with older patients. However, a patient’s joint health is more important than their specific age. That’s why it’s important for the patient and the hand surgeon to work together to assess whether tendon transfer surgery for ulnar nerve palsy is the best course of treatment.
Risks
All surgeries carry risk, though some risks are minor. Surgery produces scarring and the incision might develop an infection. Using tendon and muscle from a donor carries a slightly higher chance of infection compared with a tendon transfer of the patient’s tissues.
After surgery, the tendon will need time to heal and your hand will need to be immobilized, usually at least for one month. In conjunction with your hand surgeon, a physical therapist will start you on specific exercises to teach the muscle to function in its new location.
It’s crucial to follow all post-operative instructions and timeframes established by your health-care team. Moving the hand too early can rupture the tendon transfer. Moving it too late means stiffness from excessive scarring at the new site where tendon connects to bone.
Risks of not having tendon transfers for radial, median and ulnar nerve palsies
Without tendon transfer surgery, activities of daily living will continue to be disrupted, interfering with the patient’s ability to perform simple daily tasks. If activities such as cooking, dressing, driving or working are adversely impacted, the patient might lose independence.
Urgency
The sooner hand palsies are addressed, the sooner patients can get back to independent functioning. Many factors must be considered before undertaking this serious surgery, so it’s important to work closely with a skilled team of hand-surgery specialists with extensive experience in tendon transfer surgery.