The temporary paralysis induced by Botox injections, making them effective at reducing wrinkles on the face, has other, less superficial uses. In addition to righting crossed eyes, reducing excessive drooling, and relieving chronic headache pain, Botox is now commonly used to control involuntary muscle spasms and contractions in children with cerebral palsy (CP) and other disorders.

"I've seen two-year-olds trying to stand up, legs crossed, bent at the knees and on their tippy-toes wanting to walk," says Dr. Ellen Wood, paediatric neurologist at IWK Health Centre in Halifax, describing some of her pre-Botoxed CP patients. "Over a couple of months with therapy, some of those children are walking on their own."

Botulinum toxin

Botox is a commercial name and the popular short form for a protein molecule called Clostridium botulinum toxin, of which there are several types. When injected into a muscle, type A binds to specific presynaptic nerve terminals, essentially shutting them down, causing paralysis and muscle relaxation. Over time, neurotransmission resumes after new nerve endings sprout and reform contacts with muscle fibres. This takes from three to six months.  

"It's the brain's job to tell the muscles to relax. In CP, the brain isn't doing that so you get the constant contraction," says Wood. This effect can be mild or severe, and can take place on different parts of the body, although contracted leg muscles are common. "They may just walk on their tip-toes, or their legs may cross over in scissoring pose to the point their hips come out of the joint."

The process starts with a needle

"Just the calf muscle of one leg is four Botox injections," says Wood, adding the number of needles goes up from there. "These are intra-muscular injections, which are normally painful, and they need to be in the right place." For most kids, especially the younger ones, this means a general anaesthetic and sleeping thourhg the procedure. "If you don't, you might get the first one in the right place but the rest, no. Not with a screaming child."

Although the kids wake up feeling the same, within a few days changes are noticed. Botox's maximum effect comes in a couple of weeks. The relaxation Botox provides creates a window in which the muscles can grow and other therapies can be used to help stretch out muscles, making them more mobile.

"We might put the child's leg in a cast to help with muscle stretching and the Botox may mean just one surgery, or perhaps surgery avoided, rather than multiple operations," says Wood, adding the ongoing process is ultimately dependent on brain function. "In the long term, we don't know what will happen. We are building them up physically and giving them opportunities. If they have the ability in the brain, we can deal with the legs. Sometimes the brain can't coordinate movement and this is why the treatment doesn't always work."

But often it does, which is a special experience for Wood. "As child neurologists we don't ever make anyone better. We are dealing with injured brains. We are not used to dramatic change," she says. "But when the first child I did came back a month later walking with help, that was pretty neat."

Not bad for the most toxic protein known to humanity.