Comparison of molding helmet therapy versus natural course in twins with nonsynostotic head deformation.

This observational study aims to compare the effectiveness of helmet therapy versus natural course in twin siblings suffering from nonsynostotic head deformations. A retrospective analysis of all twin couples treated with helmet therapy between March 2009 and May 2017 at an orthopedic hospital was conducted. Inclusion criteria were me if only one twin received helmet therapy. The other twin acted as control. A classification for different head shapes was used. A total of 61 twin couples was included. Change in outcome parameters of helmet therapy and natural course differed significantly: cranial vault asymmetry (CVA) -0.66 cm vs. -0.04 cm, cranial vault asymmetry index (CVAI) -5.35% vs. -0.51% (both p < 0.001), cephalic index (CI) -3.10% vs. -1.91% (p = 0.006). Helmet therapy showed a success rate (CI < 90% and CVAI ≤7% or better) of 63.6% vs. 21.1% in children with natural course (p = 0.002). Within the limitations of the study it seems that the results of this retrospective, single-center study confirm that helmet therapy to be a reliable treatment for mild to severe positional head deformation.