Study shows botulism toxin can help treat cerebral palsy

CHICAGO -- A botulism toxin treatment sometimes used to smooth wrinkles in aging can also help improve toe-walking common in children with cerebral palsy, new research shows.

Injections of the food-poisoning toxin cause muscle weakness and are becoming an increasingly popular but little publicized treatment for stiff muscles in cerebral palsy.

The new study, involving 155 children treated for at least a year at nine centers, is one of the largest and longest-running to examine the treatment's effectiveness.

Children aged 2 to 18 received calf-muscle injections about three times a year for up to two years. Nearly half -- about 49 percent -- displayed less walking on their tiptoes six weeks after the first treatment and continued to show improvement for two years post-treatment.

The toxin enabled some children previously unable to do so to walk without braces and ride tricycles, said Dr. L. Andrew Koman, the lead researcher and an orthopedic surgery professor at Wake Forest University.

The study is published in November's Pediatrics.

The toxin was first approved in 1989 for treatment in adults of two rare nerve disorders affecting the eyes that can cause crossed eyes and involuntary eye-shutting.

After doctors treating these disorders also noticed reduced facial wrinkling, the toxin became popular in plastic surgery.

It since has been used fairly widely in the United States and abroad to treat cerebral palsy, even though it is not federally approved for such use, said Dr. Michael Sussman, president of the American Academy for Cerebral Palsy and Developmental Medicine.

"It's kind of a hot area in cerebral palsy treatment right now," Sussman said.

The preparation studied is called Botulinum toxin type A or BTX-A, sold as Botox by manufacturer Allergan, Inc., which funded the research.

Cerebral palsy is caused by brain damage, usually before birth, that impairs the ability to control muscle movement. An estimated 500,000 U.S. children and adults are afflicted.

Toe-walking caused by stiff calf muscles is a common feature. Surgery is often done on the calf tendons to help treat the condition, but botox injections, usually coupled with leg braces, can help give children time to develop a more normal walking pattern and may sometimes avert the need for surgery, said Dr. Lisa Thornton.

But Paul Greene, a Columbia University neurologist, noted that 28 percent of the children studied developed antibodies to the toxin, a high percentage he called troubling.