Sonographic Analysis of Changes in Skull Shape After Cranial Molding Helmet Therapy in Infants With Deformational Plagiocephaly

-The purpose of this study was to investigate the changes in skull shape on sonography after cranial molding helmet therapy in infants with deformational plagiocephaly.

-Twenty-six infants who were treated with cranial molding helmet therapy were recruited. Caliper and sonographic measurements were performed. The lateral length of the affected and unaffected sides of the skull and cranial vault asymmetry index were measured with calipers. The occipital angle, defined as the angle between lines projected along the lambdoid sutures of the skull, was calculated by sonography. The occipital angle difference and occipital angle ratio were also measured. All caliper and sonographic measurements were performed in each infant twice before and twice after treatment.

-The study group included 12 male and 14 female infants with a mean age ± SD of 6.2 ± 3.5 months. The mean treatment duration was 6.0 ± 2.5 months. The difference in lateral length before and after helmet therapy was significantly greater on the affected skull than the unaffected skull (16.7 ± 12.7 versus 9.0 ± 13.4 mm; P < .01). The difference in the occipital angle before and after helmet therapy was significantly greater on the affected skull than the unaffected skull (-5.7° ± 7.3° versus 4.2° ± 7.9°; P < .01). The cranial vault asymmetry index and occipital angle ratio were significantly reduced after helmet therapy (cranial vault asymmetry index, 9.3% ± 2.3% versus 3.5% ± 3.0%; occipital angle ratio, 1.07 ± 0.05 versus 1.01 ± 0.01; P < .05).

-These results suggest that occipital angle measurements using sonography, combined with cephalometry, could provide a better understanding of the therapeutic effects of cranial molding helmet therapy in infants with deformational plagiocephaly.