Assessing calvarial vault constriction associated with helmet therapy in deformational plagiocephaly

OBJECTIVE Deformational plagiocephaly and/or brachycephaly (DPB) is a cranial flattening frequently treated in pediatric craniofacial centers. The standard of care for DPB involves patient positioning or helmet therapy. Orthotic therapy successfully reduces cranial asymmetry, but there is concern over whether the orthotics have the potential to restrict cranial growth. Previous research addressing helmet safety was limited by lack of volume measurements and serial data. The purpose of this study was to directly compare head growth data in patients with DPB between those who underwent helmet therapy and those who received repositioning therapy. METHODS This retrospective cohort study analyzed pre- and posttherapy 3D photographs of 57 patients with DPB who had helmet therapy and a control group of 57 patients with DPB who underwent repositioning therapy. The authors determined the change in cranial vault volume and cranial circumference between each patient's photographs using 3D photogrammetry. They also computed a cubic volume calculated by multiplying anterior-posterior diameter, biparietal diameter, and height. Linear regressions were used to quantify effects of age and therapy type on these quantities. RESULTS A comparison of the following variables between the two groups yielded nonsignificant results: age at the beginning (p = 0.861) and end (p = 0.539) of therapy, therapy duration (p = 0.161), and the ratio of males to females (p = 0.689). There was no significant difference between patients who underwent helmeting versus positioning therapy with respect to change in either volume calculation or head circumference z-score (p ≥ 0.545). Pretherapy photograph age was a significant predictor of cranial growth (p ≤ 0.001), but therapy type was not predictive of the change in the study measurements (p ≤ 0.210). CONCLUSIONS The authors found no evidence that helmet therapy was associated with cranial constriction in the study population of patients with DPB. These results strengthen previous research supporting helmet safety and should allow health care providers and families to choose the appropriate therapy without concern for potential negative effects on cranial growth.