The Presentation of Deformational Plagiocephaly

Laura Hylton-Plank, CO

Deformational plagiocephaly has been defined as asymmetry of the skull resulting from abnormal forces acting on an intrinsically normal, developing cranium. ¹ Further distinction of the asymmetry is typically referred to as mild, moderate, or severe. These terms have commonplace acceptance in the clinical setting, although little discussion can be found within the literature. Numerous articles refer to orthotic treatment of children with severe involvement. However, few attempts have been made to define this distinction. The lack of consistent interpretation has delayed outcome studies.

REVIEW OF THE LITERATURE

Moss ² first distinguished patients into two groups: mild– moderate and moderate–severe. This distinction was made from the differences in length of the cranial vault. A length of 12 mm or less is mild–moderate asymmetry. Lengths more than 12 mm are considered moderate–severe. This does not reflect a proportion of asymmetry relative to the child's head circumference. A difference of 12 mm in a 3-month-old infant represents more asymmetry than the same difference in a child who is 11 months old.

Loveday and de Chalain ³ used a cranial vault asymmetry index (CVAI) in an effort to provide a percentage of asymmetry. Loveday defines CVAI as the absolute value of the difference in the diagonals divided by the smaller diagonal times 100. The diagonals are found at 30° from the midline of the nose. Significant asymmetry was defined as a percentage greater than 3.5%. Regardless of head circumference, the CVAI provides a constant measure that is meaningful from child to child and can be used as an assessment tool across ages. Loveday used the cephalic index to separate out brachycephalic infants. The cephalic index represents the width of the skull as a percent of the length of the skull. Loveday considered a cephalic index greater than or equal to 85% to be significant, but noted the value was arbitrarily set.

At the time of this publication, two scales of note have been presented to the orthotics and prosthetics community with the goal of standardizing the classification of head shape. Calcaterra et al. ⁴ presented a severity form to the American Cleft Palate and Craniofacial Association and the Association of Children's Prosthetic and Orthotic Clinics in 2004 that allows the observer to rate the asymmetry based on pictures of head shapes. These pictures demonstrate varying degrees of posterior flattening, ear alignment, and forehead asymmetry. This form was given to 18 physicians or medical students, and eight lay people and the participants were asked to evaluate 40 photographs of infants using a scale of 0 to 5. Stepwise regression indicated that the degree of posterior flattening and forehead asymmetry were the best predictors of asymmetry.

The Children's Healthcare of Atlanta Clinical Classification of Plagiocephaly Scale was introduced at the Association of Children's Prosthetic and Orthotic Clinics in 2004 by Plank et al. ⁵ Thirty-one variables were analyzed using a laser data acquisition system for 224 patients. Of the 224 patients, 207 received orthotic intervention and 17 control subjects received no intervention. Linear measurements, three-dimensional imaging, and volume calculations were analyzed. Four dependent variables were determined to have statistically significant validity in predicting asymmetry. Those variables were overall symmetry ratio, posterior symmetry ratio, radial symmetry index, and cranial vault asymmetry index. Concurrently, a five-level severity scale based on initial clinical findings was developed. Using all four significant variables, the clinical severity scale was validated to 90% confidence. Based on initial clinical evaluation, this scale can be used to predict outcomes. It is a progressive scale of deformity beginning at level 1, in which any asymmetry present is within normal limits, progressing to level 5, in which all four quadrants of the skull are involved with multiple secondary changes to the face, ears, and eyes.

The literature reviews confirm numerous techniques have been applied to distinguish among groups of asymmetry. Although various levels of technology are used, no methodology has received full endorsement by the medical community. The need is present in deformational plagiocephaly for a unified methodology to classify head deformity.

CLINICAL PRESENTATION

Chronic confusion in terminology has plagued the community in identifying deformational plagiocephaly. Asymmetry within the cranium varies widely and is present in us all. It is the severity of asymmetry that causes further investigation. The term deformational plagiocephaly is a diagnosis. This must be differentiated from the description of the presentation of asymmetry. The descriptors of presentation often refer to location of the largest involvement such as anterior or posterior, and right or left. Right posterior asymmetry is the most frequent presentation of deformational plagiocephaly. Another method of description is by naming the suture(s) involved, although this is commonly done when referring to synostotic plagiocephaly.

Yet a third description of asymmetry is based on severity. This description is perhaps the least understood and thus most controversial. Terminology of mild, moderate, and severe is generally accepted when describing severity of deformational plagiocephaly. It is the task of this author to articulate current opinion of treating clinicians while acknowledging that some physicians are cautious of defining boundaries, because the presentation of head shape is not the sole indicator for treatment decisions.

The presentation of deformational plagiocephaly has often been described as a parallelogram shape. Mild deformational plagiocephaly is characterized by asymmetry limited to one side of the posterior region of the cranium with no other secondary characteristics of distinction. Mild asymmetry of a single posterior quadrant does not cross midline. This presentation is best noted from a top-down view. The presence of mild deformational plagiocephaly could go unnoticed by family members or the community. As hair grows, this asymmetry is often of minimal distinction. With the progression of the deformity, discrepancy between the right and left posterior shapes will increase.

The amount of posterior flattening in the moderate designation will vary but typically involves most of the quadrant. The moderate plagiocephalic shapes mark the beginning of secondary involvement. Ipsilateral ear shift is the initial indicator for moderate severity. Moderate deformational plagiocephaly will include the clinical presentation of some or all of the following: ipsilateral ear shift, ipsilateral forehead bossing, and contralateral forehead flattening. Therefore, moderate deformational plagiocephaly is characterized by an increase in severity of posterior flattening, leading to secondary asymmetries of the forehead, ear, and skull base alignments. These secondary changes should be visually obvious to a trained observer.

The most severe head shapes involve significant asymmetries to the forehead, ears, and facial features such as the eye, cheek, or jaw. Severe deformational plagiocephaly presents with significant asymmetry in the posterior region(s), which often cross the midline, and result in abnormalities and compensations occurring throughout the cranium. In severe deformational plagiocephaly, the contralateral posterior is also bossed. This causes a visually obvious accentuation of the skull's parallelogram shape. The top-down, frontal, and pro- file views are all affected.

SURVEY RESULTS

A survey was sent to 18 clinicians (four physicians and 14 orthotists) specializing in plagiocephaly diagnosis or cranial remolding intervention. They were asked to respond to several questions regarding deformational plagiocephaly, specifically their interpretations of mild, moderate, and severe. Fourteen surveys were returned.

A synopsis of the survey results indicates several areas of agreement. The designations of mild, moderate, and severe are the most commonly used descriptors. Clinical, qualitative evaluation of several key physical presentations was found to be the largest influence in determining plagiocephalic severity. Interestingly, most of the respondents indicated that the clinical presentation was more important than measurements. Many felt linear measurements, being two-dimensional, do not comprehensively reflect the degree of deformity in the three-dimensional skull. Many clinicians reported that they do not take measurements, or that measurements were used to provide documentation for insurance coverage. Measurements could prove useful for the quantification and comparison of shape change.

Clinicians were asked to rate the influence of clinical observations in determining severity of head shape. The results are presented in Table 1 . Of note, all ratings were between 3.14 and 4.43. Ipsilateral forehead bossing was highest among influential presentations. Respondents considered the head shape increasingly severe as secondary changes increased such as forehead and facial involvement. These presentations have a greater impact on the determination of head shape severity than posterior flattening alone. The presence of torticollis also presents a significant influence in determining severity. The absence of response to a home repositioning program had only moderate influence; however, it was rated higher by physicians than orthotists.

INDICATIONS FOR TREATMENT

Treatment options for deformational plagiocephaly are another area of controversy. The presence of skull asymmetry does not immediately constitute the need for orthotic management. It is anticipated that infants present with asymmetry or abnormality of the skull at birth. Kane et al. ⁶ found the incidence of positional plagiocephaly difficult to determine because asymmetry is present in all skulls, and diagnosis is dependent on the sensitivity of the observer.

It is the opinion of the American Academy of Pediatrics in its July 2003 clinical report ⁷ that attempts at less invasive correction such as parental education of repositioning, tummy time, and range-of motion-assessments are typically the first alternative. Although infants with mild plagiocephaly could esthetically benefit with the use of an orthotic device, the natural progression of the asymmetry is relatively unknown. Further research is needed to justify medical need. Therefore, it is the severity of the diagnosis that determines treatment options.

Orthotic intervention is often recommended when there is no response to previous home programs or when secondary changes to the skull exist. Ear shift, forehead flattening, and orbital or facial involvement are clinical observations that once present should be monitored closely for progression. Moderate presentations of deformational plagiocephaly at a very early age (0–3 months) should still attempt repositioning. Physical therapy evaluation and treatment are recommended when the diagnosis of torticollis is also present.

Infants between the ages of 3 and 12 months with moderate to severe plagiocephaly are excellent candidates for cranial remolding. Orthotic treatment is appropriate when the shape does not improve, when age-appropriate at initial evaluation, or because of parental preference. Severe presentations of deformational plagiocephaly can begin treatment once appropriate neck strength has been obtained (typically not before 3 months of age). This population will strongly benefit from early intervention as less growth potential is expected with the older child.

In the hands of an experienced clinician, cranial remolding orthoses are an effective, noninvasive, treatment option for persistent moderate or severe deformational plagiocephaly. Numerous U.S. Food and Drug Administration-approved cranial remolding orthoses are currently available. Using slight alterations in design, all helmets, bands, caps, and so on, attempt to achieve a more normalized skull through strategically placed forces and directing of new growth. Until a methodology to distinguish the severity of asymmetry is uniformly accepted, further investigation into prediction of outcomes, untreated natural history, and treatment efficacy will be limited.

Correspondence to: Laura Hylton Plank, CO, Orthotics and Prosthetics Department, Children's Healthcare of Atlanta, 5445 Meridian Mark Road, Suite 200, Atlanta, GA 30342; e-mail: laura.plank@choa.org .

LAURA HYLTON PLANK, CO, is affiliated with Children's Healthcare of Atlanta, Atlanta, GA.

References:

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Plank L, Giavedoni B, Lombardo J, et al. The use of a non-invasive laser data acquisition system to quantify and compare infant head shape with non-synostotic positional plagiocephaly. Paper presented at the Association of Children's Prosthetic–Orthotic Clinics Annual Meeting; Banff, Alberta, Canada; March 24–27, 2004.
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