Neurolytic agents are injectable medications that reduce the signals traveling from the brain and spinal cord to specific muscles. When those signals are reduced, the muscle relaxes. The two agents used most often are botulinum toxin and phenol.
Your child's doctor may recommend injections to:
Reduce muscle tightness that interferes with walking
Make it easier to dress, bathe, or care for your child
Improve hand and finger function
Improve fit and comfort of braces or splints
Stop painful muscle spasms
Both agents are injected directly into specific muscles. They can be used together or combined with oral medications.
Botulinum toxin (Botox)
Muscles contract when they receive a chemical signal (acetylcholine) from a nerve. Botulinum toxin blocks the release of that chemical at the injection site. Without the signal, the muscle can't contract as forcefully, and the tightness decreases.
The medication takes about 3 days to start working. The effect lasts roughly 3 months, after which the injections can be repeated. Side effects are uncommon. Some children have temporary soreness at the injection site. Fewer than 1% report mild flu-like symptoms.
Phenol
Phenol is an alcohol-based injection that partially damages the insulating layer (myelin) around a nerve. Nerves rely on this insulation to transmit signals quickly. When it's disrupted, the signals slow down and the resulting muscle contractions are weaker. The muscle relaxes.
The effect lasts about 5 to 6 months. Over that time, the nerve repairs its insulation and the spasticity gradually returns. Phenol is often used for larger muscles or when botulinum toxin alone isn't enough.
Rhizotomy
Rhizotomy is a nerve surgery that permanently reduces muscle stiffness (spasticity) in children. Texas Children's offers different types of rhizotomy surgeries, each tailored to different needs and goals. Our multidisciplinary team works with your family to find the right fit.
Neurectomy
A neurectomy, or Selective Peripheral Neurectomy, is a procedure in which a motor nerve root is partially or fully cut to permanently reduce its ability to signal a specific muscle. Where rhizotomy works on sensory nerves in the spine, neurectomy works on motor nerves closer to the muscle itself.
Intrathecal Baclofen
Intrathecal baclofen (ITB) therapy uses a surgically implanted pump to deliver muscle-relaxing medication directly to the fluid surrounding the spinal cord. Baclofen is a medication that reduces spasticity. When taken by mouth, only a small amount reaches the spinal cord. The pump bypasses that problem by delivering the medication exactly where it's needed, at a much lower dose.
Deep Brain Stimulation
Deep brain stimulation (DBS) is a surgical treatment for dystonia, a movement disorder that causes muscles to contract involuntarily and hold abnormal postures. Dystonia is different from spasticity: spasticity is a continuous, velocity-dependent stiffness, while dystonia causes twisting, repetitive movements or sustained postures that the child can't control.
