Outcome analysis of cranial molding therapy in nonsynostotic plagiocephaly

Abstract

Background: It is known that nonsynostotic plagiocephaly does not spontaneously improve, and the craniofacial deformities that result from it. This study was conducted to analyze the effectiveness of helmet therapy for the nonsynostotic plagiocephaly patient, and to suggest a new treatment strategy based on this analysis.

Methods: A total of 108 pediatric patients who had undergone helmet therapy after being diagnosed with nonsynostotic plagiocephaly were included in this study. The patients were classified according to the initiation age of the helmet therapy, severity, and helmet wearing time. The treatment effect was compared using cranial vault asymmetry (CVA) and the cranial vault asymmetry index (CVAI), which were obtained from diagonal measurements before and after therapy.

Results: The discrepancy of CVA and CVAI of all the patients significantly decreased after helmet therapy. According to the initiation time of helmet therapy, the treatment effect was best at 5 months old or less. The helmet wearing time per day was proportional to the treatment effect up to 20 hours. In addition, the rate of the successful treatment (final CVA ≤5 mm) significantly decreased when the initiation age was 9.1 months or older and the treatment period was less than 7.83 months.

Conclusions: This study showed the effectiveness of the helmet therapy for nonsynostotic plagiocephaly patients. Based on analysis of this study, helmet therapy should be started at the age of 9 months or younger for 7.83 months or more, and the helmet wearing time should be more than 20 hours a day.

Keywords: Head protective device; Plagicephaly, nonsynostotic; Treatment outcome.

Conflict of interest statement

No potential conflict of interest relevant to this article was reported.

Figures

Fig. 1

Helmet for cranial molding therapy The helmet was customized individually according to a 3D CT scan and the measurements of the patient's head including anteroposterior, bitemporal, and diagonal distances using a spreading caliper, and circumference using a tapeline. The helmet can achieve treatment effects by inducing prominent areas to be retained passively and flattened areas to grow rapidly into the hollow space in the helmet. (A) The front, (B) the side of helmet.

Fig. 2

Diagonal measurement of patient's head The frontozygomatic-to-contralateral occipital (euryon) distance was measured using spreading calipers on both sides of each patient. The distances were defined as diagonal A (fz A to eu A) and B (fz B to eu B) (A>B), after which the cranial vault asymmetry (CVA) (diagonal A to diagonal B) and cranial vault asymmetry index (CVAI) ([diagonal A to diagonal B]/[diagonal A×100]) were measured. CVA, cranial vault asymmetry; CVAI, cranial vault asymmetry index.

Fig. 3

Photos and 3D CT: pre- and posttreatment (A) The initial CVA and CVAI were 17 mm and 11.56%, respectively, which were measured using spreading calipers. (B) The CVA decreased by 12 mm (initial CVA, 17 mm; final CVA, 5 mm) and the CVAI decreased by 8.19% (initial CVAI, 11.56%; final CVAI, 3.37%). The treatment initiation age was 6.3 months and the treatment period was 7.1 months. (C) Before the helmet therapy, a three-dimensional (3D) computed tomography (CT) scan was performed to confirm that craniosynostosis was not present. In the 3D CT scan, any discrepancy in the diagonal distances was noted. (D) When the helmet therapy was over, the 3D CT scan was performed again to assess the treatment effect. The posttreatment 3D CT scan showed the decreased discrepancy of the diagonal distances. CVA, cranial vault asymmetry; CVAI, cranial vault asymmetry index.

Fig. 4

Changes of the successful treatment rate according to the age of initiation of therapy When the initiation age of the helmet therapy was 9.1 months, the area under the receiver operating characteristic curve was 0.633, which was in the 95% confidence interval 0.535 to 0.724. This means that the rate of successful treatment was statistically different before and after the point of 9.1 months (in other words, the patients who started helmet therapy younger than 9.1 months showed a higher success rate than those who started older than 9.1 months).

Fig. 5

Differences in the successful treatment rate according to the duration of therapy When the treatment period of the helmet therapy was 7.83 months, the area under the receiver operating characteristic curve was 0.607, which was in the 95% confidence interval 0.509 to 0.700. This means that the rate of successful treatment was statistically different above and below the point of 7.83 months (in other words, the patients who had worn the helmet more than 7.83 months showed a higher success rate than those who wore it less than 7.83 months).

Fig. 6

The treatment effect of the helmet therapy strategy Only 18 of the 108 patients' experience coincided with the new treatment strategy. The mean initial diagonal (A) and (B) of these 18 patients were 145.9 mm and 130 mm, respectively, and the mean final diagonal (A) and (B) were 155.1 mm and 150.4 mm, respectively. The diagrammatic representation of the treatment effects is shown in the figure on the right.