Paralysis of the Hand & Arm

When a conscious person is unable to voluntarily move one or more otherwise normal joints of the body, that part is considered paralysed. The loss may be limited to one small joint of a finger, or involve the whole hand, the elbow, the shoulder, one side of the body, the lower half of the body or the whole body. There is a wide spectrum, and all of these are forms of paralysis.

In a normal person, the brain sends a signal to move a part of the body. The signal travels through the spinal cord to a specific nerve, then to a muscle, and the muscle, through its tendon, moves the joint. Paralysis means this chain has broken somewhere.

Paralysis can follow injury or disease anywhere along the brain, spinal cord, nerve, muscle and tendon pathway.

• Sharp injuries: a stab or cut in the neck or arm can damage nerves going to the hand, paralysing muscles of the shoulder, elbow or hand. See nerve injury.
• Head injury or stroke: damage to the part of the brain that controls the hand can paralyse one side of the body. A stroke happens when blood supply to a small but very specific part of the brain is disturbed. Brain injuries often cause tightness rather than floppiness; that is covered on the spastic hand page.
• Spinal cord injury.
• Tendon rupture: sometimes only the tip of the thumb cannot bend or straighten. This may not be a nerve problem at all but a ruptured tendon.
• Nerve disease: a viral infection of a nerve, Guillain-Barré syndrome, poliomyelitis (polio), motor neuron disease, Hirayama disease and multiple sclerosis can all present as some form of paralysis.
• Pressure on a nerve: a lump or tumour can press on a nerve and weaken only the area that nerve supplies. A normal structure can also press on a nerve. In carpal tunnel syndrome, the thickened flexor retinaculum or swollen tendon lining squeezes the median nerve, first causing tingling and numbness and later weakness.

The brachial plexus is the network of nerves that leaves the neck and supplies the whole arm. A typical injury happens when a motorcyclist falls and lands on the side of the head and shoulder, stretching or tearing these nerves. Depending on which nerves are hurt, only the shoulder and elbow, or the entire arm, may be paralysed.

Babies can suffer a similar stretch injury during a difficult birth (Erb's palsy). For parents, the brachial plexus injury and Erb's palsy guide explains what to watch for and when to seek help.

Timing matters most in this injury. Nerve repair, grafting and transfer work best when done early, so anyone with a weak or limp arm after an accident or birth should be examined promptly.

After an injury to the radial nerve, a person may be unable to lift the wrist, straighten the fingers or lift the thumb. This is called wrist drop. It can follow a fracture of the humerus (upper arm bone), because the radial nerve runs very close to the bone.

Many radial nerve injuries recover on their own and are watched with splinting and regular examination. When recovery does not come, nerve surgery or tendon transfers can restore wrist and finger extension.

Reconstructive surgery can restore movement, grip and independence in some neurological conditions, but not all nerve diseases are suitable. The main tool is tendon transfer: a healthy, spareable muscle is rerouted to replace a paralysed one. For this to last, the patient's weakness must be completely stable.

Why progression matters

The single most important question is whether the condition is still progressing or has stopped. If a disease is still destroying nerve cells, the muscle chosen as a donor will eventually lose its nerve supply too, and the reconstruction will fail. For this reason, progressive motor neuron diseases such as ALS are not suitable for this kind of surgery.

Some conditions do qualify, because their damaging phase comes to a complete halt:

• Post-polio residual paralysis (PPRP): polio damages motor nerve cells, but the destruction stops once the acute viral illness is over. It leaves a stable pattern of weakness, spares sensation, and usually leaves good donor muscles. It remains a classic indication for reconstruction.
• Guillain-Barré syndrome (GBS): an acute, one-time autoimmune attack on the peripheral nerves. Most patients recover almost completely over months. A small number are left with permanent weakness. Once that weakness has fully plateaued, tendon transfers can safely restore specific lost movements.
• Leprosy (Hansen's disease): a bacterial infection that damages particular nerves in predictable patterns. Once the full course of multi-drug therapy (MDT) is complete and the infection is arrested, stable deformities such as a claw hand can be corrected using strong, unaffected donor muscles.
• Hirayama disease: a mechanical motor neuron disorder that progresses during adolescence and then stops on its own, usually after 3 to 5 years. Because it typically spares certain forearm muscles such as the brachioradialis, it leaves good donors to rebuild thumb opposition and finger extension once the disease has halted.

Surgery can improve many paralytic conditions and the quality of life that goes with them. Depending on the cause and how long ago it happened, treatment may involve nerve repair, nerve grafting, nerve transfer, tendon transfer, removing whatever is pressing on the nerve, or joint surgery such as arthrodesis.

• Nerve repair: a damaged nerve is repaired under the microscope. In young patients and under the right conditions, a well-repaired nerve regrows over time.
• Nerve grafting: when the gap between the two nerve ends is too long to join directly, it is bridged with a nerve graft, usually taken from the leg. The most common donor is the sural nerve.
• Nerve transfer: a nerve gives off many branches, the way a tree trunk does. One branch that can be spared is rerouted to plug into the paralysed nerve, reconnecting it to the brain and bringing the target muscle back to work.
• Tendon transfer: the body has spare capacity in many places; a person can live a normal life with one kidney, for example. Muscles are similar. A muscle the hand can spare is relocated to do the job of a more important muscle that is paralysed.
• Arthrodesis (joint fusion): joints work together, and one badly positioned joint drags the others out of position. Fusing one joint in a good position can greatly improve how the other joints work. Fusion can also free up muscles for transfer elsewhere, increasing overall hand function.

Patients with paralysis often come for treatment after a long delay. After a significant delay, nerve surgery may no longer work, and the options shift to tendons and muscles.

Tendon surgery needs the target joints to be soft, supple and passively mobile, meaning they can be moved fully by hand. Stiff joints may first need a long period of dynamic splinting, or a preliminary operation, to loosen them before the tendon transfer is done. Splints for this are made in-house at the clinic.

Book a consultation to find out which options are still open in your case.