Therapy effects of head orthoses in positional plagiocephaly

Abstract

Purpose

Head orthoses offer a valuable therapeutic option for infants with positional plagiocephaly. The aim of this retrospective study was to evaluate the influence of therapy start and duration due to improvement of cranial asymmetry.

Material and methods

A total of 102 children during the years 2009–2014 were included. The patient cohort was divided according to age at the beginning of therapy (younger/older than 7.5 months) and duration (less/more than 150 days). To evaluate the therapy, ear shift (ES), Cranial Vault Asymmetry Index (CVAI), and Cranial Index (CI) were calculated pre- and post-therapy by using three-dimensional photogrammetry measurements.

Results

Treatment with head orthoses led to a significant reduction of CVAI in groups with less and more than 150 days of therapy (p < 0.0001). A significant reduction in CVAI was observed (p = 0.0235) in children younger than 7.5 months in short-term therapy. At the end of therapy, no significant difference was found in the groups, whether treated with short- or long-term head orthoses (p = 0.0813), although CVAI was significantly different comparing the third time point of both groups for treatment duration (p = 0.017). The major positive effect of helmet therapy has been seen after 75 days of treatment. A treatment that was longer than 150 days did not show any significant improvement concerning the cranial asymmetry.

Conclusions

Helmet therapy is a reliable method in the treatment of positional plagiocephaly to improve cephalic asymmetries. This retrospective study indicates that an early beginning can lead to satisfying results after short-term therapy.

Introduction

The American Academy of Pediatrics recommended in 1992 (AAP, 1992) that infants should be laid on their backs to sleep, which led on the one hand to a fortunate reduction in sudden infant death syndrome (Moon et al., 2007), but unfortunately also led to a significant increase in the incidence of infant cranial asymmetry, known as positional plagiocephaly (Kane et al., 1996, Turk et al., 1996). The incidence of this cranial asymmetry increased between 1979 and 1996 from 1:300 to 1:60 (Graham et al., 2005). More recent investigations have demonstrated that positional plagiocephaly occurs in approximately 20% of all infants (Collett, 2014) and is usually first noted up to 4–8 weeks after birth. Lateral plagiocephaly with a one-sided flattening of the occiput is differentiated from brachycephaly, which features a central flattening of the occiput. Mixed forms of both asymmetries are common (Argenta et al., 2004). One third of all newborns display a one-sided asymmetry in the mobility of the head joint (Buchmann et al., 1992). The one-sided limitation of head movement is caused by segmental functional disorders primarily in the area of the head joint (Dörhage, 2010b). The asymmetry of the infant head is described as a possible consequence of these functional disorders (Biedermann, 2006, Frymann, 1976). Lateral plagiocephaly has already been classified into two different degrees of severity by Moss, whereby a measure for cranial asymmetry is given by the difference between a long skull diagonal and a short skull diagonal on a horizontal plane. A mild to moderate asymmetry is defined by values of up to 12 mm and a moderate to severe asymmetry by values greater than 12 mm (Moss, 1997). A significantly more precise three-part classification of cranial asymmetry in cases of positional plagiocephaly has been described by Wilbrand et al (Wilbrand et al., 2012a). Alongside three different cranial asymmetry groups, the age and gender of the child is also taken into account. Normal percentile curves have been developed based on the Cranial Index (CI) and the Cranial Vault Asymmetry Index (CVAI). Severe asymmetries display values above the 97th percentile, moderate asymmetries between the 90th and 97th percentiles, and mild asymmetries between the 75th and 90th percentiles (Wilbrand et al., 2012a). Affected infants up to the age of 6 months undergo different forms of therapy: positioning techniques, physiotherapy, chirotherapy, Arlen Atlas therapy, and osteopathy. An indication for helmet therapy arises when previous therapies, such as positioning techniques, physiotherapy, chirotherapy, Arlen Atlas therapy, and osteopathy, have demonstrated insufficient improvement in cranial asymmetry and a moderate to severe cranial asymmetry is still present (Dörhage, 2010a). Cranial asymmetry improves in children with helmet therapy more effectively than in children without helmet therapy (Kim et al., 2013, Kluba et al., 2014a). Complications during helmet therapy occur in 25.4% of cases, but have a mild degree of severity and in most cases diminish spontaneously (Wilbrand et al., 2012b). The treatment of children with positional plagiocephaly is usually interdisciplinary. Prompt transfer to a specialist and simultaneous application of different treatments is recommended (Kluba et al., 2014b). The selection of the different therapies should be guided by the individual dysfunctions and the patient-specific risk factors (Steinberg et al., 2015).

In the retrospective study presented here, observations were made in 102 infants and children below the age of 2 years with positional plagiocephaly who had undergone therapy with head orthoses (known as helmet therapy). The process of the therapy was documented by using three-dimensional imaging photogrammetry. Different therapy effects in relation to the success of the therapy, and the changes in cranial asymmetry (Cranial Vault Asymmetry Index, Cranial Index, Ear-Shift), were analysed and described.

The aim of this retrospective analysis was to investigate whether the age of the child at the start of therapy affected the effectiveness of helmet therapy. Furthermore, evaluation was to be made as to from which therapy interval no more significant improvement in cranial asymmetry occurred.