Researchers at the University of Michigan Orthotics and Prosthetics Center conducted a retrospective cohort study of infants treated for positional plagiocephaly with a cranial remolding orthosis (CRO). The overall success rate for CRO treatment was 75 percent, however the researchers found that success rates varied from 6-98 percent depending on the severity of the condition and the child’s age when the treatment was initiated.
“Due to the malleability of infants’ skulls, prescribing a helmet before six months of age increased the chances of achieving a symmetric head shape,” said Hannah Gensch, resident orthotist.
Three hundred infants with deformational plagiocephaly who were treated with a CRO were categorized by age at initiation of orthotic treatment (less than 22 weeks, 22-25 weeks, 26-30 weeks, and more than 30 weeks) and into groups by severity of their deformity (initial cranial vault asymmetry of 6-9mm, 10-12mm, 13-16mm, and greater than 17mm). A successful outcome was defined as achieving a final cranial vault asymmetry of 5mm or less.
“We measured the largest diagonal diameter of the head from the forehead to the back of the skull to determine the size of the helmet. The helmet stops the growth of the largest part of the skull and allows room for the rest of the skull to grow that size, so the child ends up with a symmetric oval shape,” Gensch said. “The helmets allowed the flattened areas of the head to grow until they matched the rounded areas.”
The results showed that the chances of achieving a symmetric head shape were significantly greater when the infant’s deformity was moderate and somewhat greater when the helmet was provided at less than six months old. Severity had a more significant effect on success rates than age at initiation. The age at initiation became more influential in determining the likelihood of success when the infant’s deformity was severe.
“If the infant had a severe deformity or was prescribed the helmet later in infancy, the chance the infant would reach fully symmetric head shape was decreased. However, it was still common to see at least a 50 percent improvement in head shape,” Gensch said.
Editor’s note: This story was adapted from materials provided by the University of Michigan.
The study, “Success rates of cranial remolding orthosis treatment of plagiocephaly based on initial presentation,” was published in the Journal of Prosthetics and Orthotics.