Selective posterior rhizotomy is a surgical procedure done to relieve the muscle tightness or spasticity that occurs in patients with cerebral palsy. During this procedure, the posterior nerve roots in the lower spinal region that contribute to muscle spasticity are identified and cut. Preventing excess signals from these nerves may allow the patient to have more control over muscle movement and improve the quality of life.
Cerebral palsy is caused by an injury to the brain that can occur either before, during, or shortly after birth. This injury is usually permanent and can interfere with the electrical signals that are sent back and forth between the brain and the muscles. Two types of nerve fibers must function together to send and receive signals to and from the muscles: sensory fibers send signals from the muscle to the spinal cord, while the motor nerve fibers send signals from the brain to the muscle.
Motor nerve fibers in cerebral palsy patients do not function properly, which leads to an increase in signals from the sensory nerves to the spinal cord. This increase causes muscle tightness, which, in turn, causes patients to have poor muscle coordination. Various forms of surgical and physical therapy are available to help patients regain muscle control. Selective posterior rhizotomy is one surgical therapeutic option that can reduce the signals from the sensory nerve fibers and improve patient mobility.
The selective posterior rhizotomy is usually performed on children between the ages of two to five years old. Patients must undergo a variety of tests before the surgery to determine the extent of the muscle spasticity. Once a patient is a candidate, the child can be admitted to the hospital. The surgery is performed while the patient is under general anesthesia.
To perform the selective posterior rhizotomy, the surgeon makes an incision through the skin of the lower back. One or more vertebrae in the lumbar and or sacral region of the spinal column are exposed. Removal of the lamina, the bony process on the vertebra, must be done to expose all the nerve roots. Sensory nerve roots and motor nerve roots are separated from each other and the motor roots are covered to ensure they are not disrupted.
The sensory roots are stimulated with electrical probes to determine which nerves are causing spasticity in the patient. These roots are then severed so that the signals can no longer travel along those nerves. This is a permanent surgery, so the surgeon must carefully decide which nerves to cut. Once the nerves are cut, the patient may experience muscle weakness even though the tightness has disappeared. The muscle strength can be built up again through a rigorous physical therapy program, and the patient should have greater control over muscle movement.