Methods to Diagnose, Classify, and Monitor Infantile Deformational Plagiocephaly and Brachycephaly: A Narrative Review

Abstract

Objective

The purpose of this study is to review the literature for possible methods in diagnosing, classifying, and monitoring deformational plagiocephaly and brachycephaly.

Methods

A search was conducted on articles through February 2014 in PubMed (Medline) and Google Scholar. Articles were included if they met the following criteria: (1) they were written in English or German; (2) they involved humans; (3) they were published in the last 10 years; (4) they had a primary research question about all possible methods for diagnosing, classifying, and monitoring deformational plagiocephaly and brachycephaly; and (5) an abstract was available.

Results

The search resulted in 58 articles. After the review, the number was reduced to 16. Of the 16 articles included, 9 were reliability studies on measurements of deformational plagiocephaly. Six measurement tools for diagnosing, classifying, and monitoring deformational plagiocephaly and brachycephaly were found: visual assessment, anthropometric measurements with a caliper, measurements with a flexicurve, plagiocephalometry, 3-dimensional photography, and radiological imaging.

Conclusion

This study found that visual assessment, flexicurve, anthropometric measurements with a caliper, and plagiocephalometry are useful measurements. At present, the plagiocephalometry and the anthropometric measurements with a caliper are more reliable methods than the visual assessment and the measurement with a flexicurve.

Introduction

Cranial asymmetry in infants due to nonsynostotic deformation of the skull, also called positional or deformational plagiocephaly (DP), has been documented in the literature since 1992.¹ In 1992, the American Academy of Pediatrics released a statement recommending that infants should sleep in the supine position, which has lowered the incidence of sudden infant death syndrome by 40%.² A consequence of the recommendation is the increasing incidence of DP.³ The incidence of DP was found to be 46.6% in 7- to 12-week-old infants in a cohort study carried out in 2013.² Of these infants, 63.2% were affected on the right side. Deformational plagiocephaly occurs primarily in infants with a preference for turning their head to one side or infants suffering from torticollis.⁴ Furthermore, there is some evidence that intrauterine constraints can cause DP⁵ and, moreover, that intrauterine constraints and birth trauma can lead to asymmetry and, consequently, to DP.⁶ Rogers³ stated that infants are more affected on the right side because of the common left occiput anterior intrauterine position, where the fetus lies with the head in a slight right rotation. In addition to DP, brachycephaly, a symmetrical occipital flattening and compensatory parietal widening, is often seen in infants without a preferred head rotation as a consequence of the recommended supine positioning.³

Currently, there are no standards for diagnosing, classifying, and monitoring DP and brachycephaly.^{7, 8} Likewise, there are no standards for deciding whether or not to treat and which treatment, like for example active repositioning, physical therapy, orthotic helmets, or chiropractic or manual therapies, to choose. In general, DP and brachycephaly are considered cosmetic problems, although children with severe DP might have a higher risk of strabismus and auditory problems.⁹ In addition, facial asymmetry due to DP might lead to mandibular asymmetry, which can change the form and function of the orofacial system.^{9, 10} A causal relationship between DP and secondary changes in the orofacial system, however, has not yet been established. Brain dysfunction with developmental delays is sometimes associated with DP and brachycephaly.⁹ This hypothesis, however, has not yet been confirmed, and it is more probable that the developmental delay causes skull deformity than vice versa.

Chiropractors and other practitioners working with infants are often confronted with DP in combination with preferred head rotation to one side, and infantile torticollis. Furthermore, parents of children with brachycephaly might choose to consult a chiropractor for advice and treatment. Therefore, the purpose of this article is to review the literature for methods in diagnosis, classification, and monitoring of DP and brachycephaly.

Methods

A search was conducted through February 2014. The search was performed on the following databases: PubMed (Medline) and Google Scholar. In addition, the reference lists of the retrieved articles were screened. Articles were included if they met the following criteria: (1) they were written in English or German; (2) they involved humans; (3) they were published in the last 10 years; (4) they had a primary research question about all possible methods for diagnosing, classifying, and monitoring DP and brachycephaly; and (5) an abstract was available. Excluded were articles that described craniosynostosis and articles that measured outcomes of treatments of DP and brachycephaly.

Search Terms

The first search included the keywords plagiocephaly and diagnosis. Then, the keywords plagiocephaly and diagnosis were combined with measurement and classification. The second search included the keyword positional plagiocephaly, the third search included the keyword deformational plagiocephaly, the fourth search included the keyword non-synostotic plagiocephaly, and the fifth search included brachycephaly. The second, third, fourth, and the fifth keywords were then each combined with the words diagnosis, measurement, and classification.

Results

The search resulted in 58 articles that were all carefully reviewed. After the review, the number was reduced to 16. Articles were excluded from the review if they were not relevant to the research question. Of the 16 articles included, 9 were reliability studies on measurements of DP. The 9 nonreliability studies found in the search included reviews of DP in general. Brachycephaly is less discussed in general in the medical literature, probably because of the posterior, symmetric skull deformity without ear shift and facial scoliosis.

Altogether, 6 measurement tools for diagnosis, classification, and monitoring DP and brachycephaly were found: visual assessment/clinical classification, anthropometric caliper measurements, flexicurve, plagiocephalometry/molding device, 3-dimensional (3D) photography, and radiological imaging. The 6 measurement tools and the results of the 9 reliability studies from the literature search are described in Table 1.

Table 1.

The Six Measurement Tools and the Results of the 9 Reliability Studies From the Literature Search

Measurement Tool	Description	Reliability Studies	Result
Visual assessment/clinical classification	Louis Argenta was the first to present a visual assessment of skull deformity in 1998.11, 12 In his assessment, patients are clinically examined in 4 positions: from the front, from above, from the back, and from the side. The visual assessment according to Argenta is listed in Table 2. Argenta (2004)12 also developed a clinical classification of DP and brachycephaly based on visual assessment. The classification should help clinicians to evaluate severity and to decide on treatment options. The classifications are listed in Tables 3 and 4.	Spermon et al, 2008: 20 patients aged 0-1 y were classified for DP by 9 different experts from 3 different professions (pediatricians, physiotherapists, and manual therapists). The raters were nonexperienced and had undergone 1 single training session in assessing DP. The assessors in this study were randomly assigned to separate rooms to rate the infants. Reliability was determined separately for the type/classification of DP and each characteristic clinical feature. All 9 raters examined all of the 20 patients at the first assessment. The assessments were performed twice within a period of 2 wk to measure intrarater reliability. For the second assessment, only 3 raters were present.	The results showed almost perfect intrarater reliability. The interrater reliability for classifying DP was moderate.
Anthropometric caliper measurements	These measurements are taken with anthropometric spreading or sliding calipers (Fig 1). The objective parameters should be length, width, and oblique distances. In addition, the head circumference should be measured. These measurements allow the practitioner to diagnose, classify, and monitor plagiocephaly and brachycephaly.15 The value of each measurement lies in the comparison with age-related norms and the individual patient at another point in time.15, 23 In addition, the value lies in using correct landmarks on the skull for the measurement. The landmarks recommended by Wilbrand are listed in Table 5.	Wilbrand et al, 2011: In this study, 3 examiners measured 30 infants with DP. Each parameter (with clear landmarks) was measured 6 times within 1 d to test for intrarater variability. To ensure study blindness, the examiner took a break after studying a patient and measured other patients before remeasuring the first patient. The interrater variability was assessed separately for every measurement.	The results demonstrated the consistency of the measurement techniques with high intra- and interrater reliability.
Anthropometric caliper measurement and visual assessment		Mortenson et al, 2006: The intrarater and interrater reliability in 71 infants with DP was measured. Two clinicians independently measured the CVAI on infants using anthropometric measurements. The 2 clinicians were not aware of each other’s measurements. The patients were measured 3 times by each clinician. In addition, the infants were viewed by an assessor, unaware of the results of the measurements, from 5 views: front, back, left profile, right profile, and from above. A 3-point Likert scale was then used for the visual analysis of asymmetry.	The results showed moderate intrarater reliability and poor interrater reliability. A poor correlation between anthropometric measurements with a caliper and visual analysis by an assessor was found.
Anthropometric caliper measurement and visual assessment		Glasgow et al, 2007: In this study of 192 infants, anthropometric measurement was performed by 1 research assistant and the visual analysis by another, and the 2 results were compared.	A good correlation was found between the TDD measured with a caliper and visual assessment.
Flexicurve	The flexicurve is an easy and inexpensive tool for measuring DP and brachycephaly.16 The flexicurve is placed on the infant’s head in vertical alignment with the nasion and inion (Fig 2). The nasion and inion can be marked on the infant with a skin-sensitive pen and should be visible above the flexicurve when placing it on the infant’s head. The flexicurve should then be carefully lifted off the head and placed on a CVAI form paper. With a sharp pencil, the head circumference, the midpoint of the head, and 2 diagonals can be traced and the CVAI measured (Fig 3). A perfectly symmetrical head should have a CVAI score of 0%. A head is considered to have significant asymmetry if the CVAI is >−3.5%.16	Leung et al, 2013: In this study, 34 infants were measured twice by 2 different physiotherapists within 1 h to measure intrarater reliability. Both physiotherapists examined 18 of the infants to measure interrater reliability. The physiotherapist placed the flexicure, but another person completed the calculation of the CVAI after the session, ensuring that the therapists were unaware of the results when remeasuring the infant.	The result of this study shows that the flexicurve is a reliable measurement for calculating the CVAI and that CVAI is a reliable tool for measuring plagiocephaly.
Plagiocephalometry/moulding device	Plagiocephalometry is a clinical method for quantifying asymmetry of the skull.9 Physiotherapists, especially in the Netherlands, often use this method. Plagiocephalometry is performed with a strip of thermoplastic material which is positioned around the infant’s head at the widest transverse circumference (Fig 4). In 2-3 min, the ring has hardened, and landmarks are marked perpendicularly on the ring in a standardized manner: both ears (posterior edge of the tragus) and the middle of the nose bridge. The ring is then removed from the head, and another landmark is made representing the middle of the posterior circumferential distance between the left and right ear (Fig 5). Then the upper side of the ring is photocopied onto paper and onto a transparent sheet. On the paper copy, 9 lines are drawn and measured to the nearest millimeter. From this, the degree of asymmetry can be calculated (Fig 6). The transparent sheet is used for follow-up purposes.9	van Vlimmeren et al, 2006: The reliability of plagiocephalometry was measured in 50 children (aged 0-24 mo) with or without positional preference of the head and with or without DP. They were measured 3 times by 2 separate, experienced pediatric physical therapists on the same day within 30 min. Altogether, 150 rings were measured for 50 children, twice by 1 physiotherapist and once by the other, to measure intra- and interrater reliability. The physiotherapists copied the rings, drew the lines, and made the calculations.	Intraclass correlation coefficients regarding the measurements of the drawn lines were all greater than 0.92 (intrarater reliability) and 0.90 (interrater reliability), giving a high statistical reliability.
Plagiocephalometry/moulding device		Spitzer, 2011: Comparing optical 3D imaging to plagiocephalometry and a CT of 10 symmetrical and asymmetrical head models.	There were no statistically significant differences in the results, showing plagiocephalometry to be a valuable tool in measuring DP.
3D photography	3D photogrammetry has advantages in the quantification of angles, surfaces, and volume in contrast to 2-dimensional methods.8 Several commercial imaging systems are available specifically for DP. They are mainly structured for manufacturing orthotic devices.8 In addition to 3D photography, 2-dimensional photography with a headband and a specially developed software program has been described in the literature and validated in a study by Hutchison et al24 in 2005. This method has, to the author’s knowledge, been replaced with 3D photography. An example of a 3D evaluation is seen in Fig 7.	McKay et al, 2010: 3D photographic images and CT scans (criterion standard) of 90 patients with DP (both taken within a period of 3 mo) were collected over a period of 3½ y. The 3D photographic and 3D CT images were placed in a parallel plane, overlapped, and studied in the anterioposterior and sagittal planes using 14 pairs of soft tissue landmarks.	A greater than 0.91 correlation coefficient between measurement by CT and 3D photograph was found. High interrater reliability.
3D photography and anthropometric caliper measurement		Schaaf et al, 2010: The accuracy of 3D photogrammetry compared with anthropometric measurements, using calipers on 100 infants, was studied. The anthropometric measurements and 3D photogrammetry were carried out on the same day. In addition, the study measured intrarater (variance of measurements) and interrater (variance of the observers) concordance.	The result showed that the CVAI was approximately 2% lower in the anthropometric measurements than in the photographic. The intrarater and interrater reliability proved to be excellent.
Radiological imaging	Radiographic imaging and CT have been used, and are sometimes still used, as a diagnostic tool for DP. The CT scan, based on 2-dimensional slices, reconstructs the patient’s head 3-dimensionally, giving a perfect diagnostic tool.17, 18	No reliability studies found

3D, three-dimensional; CT, computer tomography; CVAI, cranial vault asymmetry index; DP, deformational plagiocephaly; TDD, transcranial diameter difference.

Discussion

Reliable instruments are needed for the diagnosis, classification, and monitoring of DP in infants. They must be based on clear cutoffs and repeatable measurements to ensure clinical reliability and validity. Furthermore, the instruments should be relatively inexpensive and relatively easy to apply within a reasonable time frame in a busy practice. More importantly, the parents should understand the examination and be able to follow the development of their child’s head form. The instruments should allow for accurate communication between clinicians and families (Table 2, Table 3, Table 4, Table 5).

Table 2.

Visual Assessment of DP and Brachycephaly According to Argenta (2004)¹²

Anterior view	Here, the clinician can determine if there are asymmetries of the forehead and of the face.
View from above	Forehead asymmetry, posterior cranial asymmetry, and malposition of the ears can be evaluated. In addition, abnormal bulging of the temporal fossa is most likely to be seen in this view.
Posterior view	This view allows confirmation of ear position and posterior asymmetry. In addition, it allows the evaluation of the widening of the posterior skull.
Lateral view	This view can detect abnormal vertical growth.

Table 3.

Clinical Classification of DP After Argenta¹²

Type 1	DP is limited to the back of the skull. In older children who are beginning to grow mastoid processes, the asymmetry may extend a little laterally.
Type 2	Variable degree of posterior cranial asymmetry. Displacement of the ear forwards and/or downwards.
Type 3	Posterior cranial asymmetry, malposition of the ipsilateral ear, and ipsilateral frontal bone protrusion.
Type 4	Type 3 and ipsilateral cranial asymmetry. Often, the facial asymmetry is purely soft tissue. In severe cases, bony asymmetry may develop.
Type 5	Temporal bulging or abnormal vertical growth in addition to type 4. These cases demonstrate an anatomical attempt at decompression of the growing brain.

DP, deformational plagiocephaly.

Table 4.

Clinical Classification of Brachycephaly After Argenta¹²

Type 1	A depression of the central skull at the confluence of the lambdoids with the sagittal suture. The position of the ears, forehead, and face is otherwise normal.
Type 2	Type 1 and widening of the skull in its posterior half as the brain attempts to decompress.
Type 3	Type 2 and vertical growth of the posterior skull and/or temporal bulging. This is a reflection of an extremely flat, constricted skull.

Table 5.

Landmarks for Anthropometric Measurements (Wilbrand et al, 2011)¹⁵

Measurements	From	To
Lengtha	Glabella	Opisthocranium
Widtha	Eurion; the eurion point is read 1 cm above the otobasion superius point. A possible ear shift due to cranial asymmetry has to be considered: the measurement points have to be shifted in accordance with the ear shift. Possible asymmetry of the skull base is respected by this procedure.	Eurion; the eurion point is read 1 cm above the otobasion superius point. A possible ear shift due to cranial asymmetry has to be considered: the measurement points have to be shifted in accordance with the ear shift. Possible asymmetry of the skull base is respected by this procedure.
Obliquea	Lateral point of the ipsilateral eyebrow (frontotemporal point)	Contralateral occiput area in closest proximity (lambdoidal point; inner rim of the lambdoid suture)
Circumferencea	Measurement has to include the glabella and opisthocranium. The lower edge of the measurement tape lies directly above the eyebrows.	Measurement has to include the glabella and opisthocranium. The lower edge of the measurement tape lies directly above the eyebrows.

^aAll measurements must be taken in strictly horizontal manner.

Visual assessment is an excellent way of communicating and explaining to parents the shape of a baby’s head. Although visual assessment and classification have been standard practice since 1998, their reliability was not tested before 2008. In the study by Spermon et al (2008),¹¹ the intrarater reliability was shown to be excellent and the interrater reliability for classifying DP to be moderate. Weaknesses of this study are the small population of 20 infants and the inexperience of the raters, as more experienced raters would possibly lead to higher concordance. In addition, a 2-week period between the 2 assessments is not ideal because of infants' head growth and possible counterpositioning treatment carried out by parents to improve DP. On the contrary, a shorter time period between assessments would allow the raters to remember what they said the first time.

The clinical classification of DP, using the visual assessment proposed by Argenta,^{11, 12} is a good tool for the clinician to use when discussing the development of the child’s head shape with the parents. However, because the classification lacks numbers, it loses its value. In a study by Wilbrand et al (2012),⁷ a suggested clinical classification of infant DP, using anthropometric caliper measurement, was contained, with a database analysis of more than 400 children, to help guide the clinician in treatment decision (Figs 2 and 3). They suggested that children with DP could be allocated into a reliable 3-level severity category depending on their cranial vault asymmetry index (CVAI): mild (between 75th and 90th percentile), moderate (between 90th and 97th percentile), and severe (above 97th percentile).

$$\mathrm{CVAI}=\frac{\mathrm{Short}\mathrm{diagonal}–\mathrm{Long}\mathrm{diagonal}}{\mathrm{Short}\mathrm{diagonal}}\times 100\%$$

Fig 2.

Placement of the flexicurve (Copyright; Leung, Watter and Gavranich. University of Queensland, Australia). (Color version of figure appears online.)

Fig 3.

mCVAI (cranial vault asymmetry index) tracing and calculation (Copyright: Leung, Watter, and Gavranich; University of Queensland, Australia).

This classification is, in comparison with that from Argenta, a quantifiable measurement tool that is important for an objective documentation of the development of the infant’s head. In clinical practice, however, visual assessment and a quantifiable measurement tool, like for example anthropometric caliper measurement, are more likely to be used simultaneously because a visual assessment gives an opportunity to discuss individual head shape with the parents, whereas the quantifiable measurement tool gives a numeric classification of the head shape. The anthropometric caliper measurements used in combination with visual analysis have been studied in 2 different studies; Mortenson and Steinbok¹³ found that there was a poor correlation between anthropometric measurements with a caliper and an assessor who was visually analyzing and classifying infants with DP. In the study by Glasgow et al,¹⁴ however, a good correlation between the transcranial diameter difference (Fig 1) measured with a caliper and visual assessment was found. The larger population involved in the study from Glasgow et al makes it more credible.

Fig 1.

Spreading caliper showing oblique measurement.

The anthropometric caliper measurement is widely used in clinical settings. It is noninvasive, reasonable in cost, and easy to apply in clinical practice, taking only a few minutes. Two studies have tested the reliability and variability of this instrument. In the study by Mortenson and Steinbok¹³ in 2006, moderate intrarater reliability and poor interrater reliability were found. In the second study, conducted by Wilbrand et al,¹⁵ a consistency of the measurement techniques was found with high intra- and interrater reliability. One of the reasons for the high clinical reliability of this study, in comparison to the study done by Mortenson and Steinbok, could be the use of clear landmarks for measurements on the infant’s head. In addition, the examiners in the study of Wilbrand et al were experienced in anthropometric caliper measurement. The study of Mortenson and Steinbok does not mention whether the clinicians carrying out the measurement were experienced or not. However, the larger population involved in the study of Mortenson and Steinbok compared with the study of Wilbrand et al makes the study of Mortenson and Steinbok more credible. In both studies, infant behavior during measurement could have led to error. In clinical practice, it is very important to use the same clear landmarks for measurements on an infant’s head. When measuring circumference of the head (Table 5), the Centers for Disease Control and Prevention head measurement charts should ideally be used simultaneously to monitor the growth of the infant’s head.

The flexicurve is an inexpensive tool for measuring positional skull deformation. It is not widely used in clinical settings in Europe. The study by Leung et al¹⁶ showed that the flexicurve is a reliable measurement for calculating the CVAI and that CVAI is a reliable tool for measuring plagiocephaly. The small number of infants is a limitation of this study. In addition, the short interval between measurements can lead to error, as a clinician’s memory may make it easier to place the flexicurve at the same position after a short time. In practice, a limitation to the flexicurve is the challenge of obtaining a correct head mould when the infant is unsettled. In addition, in infants with a lot of hair, the moulding of the flexicure is difficult. Most errors probably occur when taking the flexicurve from the infant’s head on to the paper, as slight pressure changes the shape of the flexicurve. The time needed to carry out the measurement is short (ie, less than 10 minutes).

Plagiocephalometry is said to be an accurate, cost-effective, and noninvasive method for assessing skull asymmetry.⁹ In the study by van Vlimmeren et al,⁹ the intraclass correlation coefficients regarding the measurements of the drawn lines were all greater than 0.92 (intrarater reliability) and 0.90 (interrater reliability), giving a high statistical reliability. Considering the fact that the plagiocephalometry hardens while on the infant’s head, it is unlikely that errors will occur when removing it from the infant’s head as, for instance, with the flexicurve. However, bias might have occurred in the calculations when measuring the intrarater reliability because the same person made the calculation within 30 minutes for the same infant. Tracing the landmarks on the ring, especially the middle of the nose, can be difficult and can therefore cause errors in measurements⁹ (Fig 4, Fig 5, and 6).

Fig 4.

Plagiocephalometry. A strip of thermoplastic material positioned around the infant’s head at the widest transverse circumference. (Color version of figure appears online.)

Fig 5.

Plagiocephalometry. After removing the ring from the head, a landmark is made representing the middle of the posterior circumferential distance between the left and right ear. (Color version of figure appears online.)

Fig 6.

Plagiocephalometry measurement on the paper copy (Copyright: EKWIP, Dr Leo van Vlimmeren). AD, anterior dextra; AP, anterio posterior; AS, anterior sinistra; ED, ear deviation; ODL, oblique diameter left; ODR, oblique diameter right; PD, posterior dextra; PS, posterior sinistra; SD, sinistra dextra. (Color version of figure appears online.)

In a further study, Spitzer et al¹⁷ considered the validity of plagiocephalometry by comparing the results of a plagiocephalometry measurement with a computer tomography (CT) of 10 symmetrical and asymmetrical head models. There were no statistically significant differences in the results, showing plagiocephalometry to be a valuable tool in measuring DP.

In the author’s opinion, the plagiocephalometry is superior to the flexicurve. Fewer errors are caused when removing the ring from the infant’s head because the ring hardens. Photocopying the ring before making calculations, rather than drawing lines directly on a CVAI paper, as in the case of the flexicurve, definitely minimizes errors. Nevertheless, plagiocephalometry is not always ideal. First, experience is needed to safely identify the largest circumference of the head. In addition, the strip takes 2 to 3 minutes to cure, and during this time, a child’s head movements will reduce the accuracy of the measurement technique. The clinician has to spend 10 to 15 minutes measuring the lines after photocopying the ring, which is not always practical in a clinical setting.

Three-dimensional photography is an excellent tool because it reproduces the infant’s head including angles, surfaces, and volume. In addition, the time of data acquisition is short, so the problem of movement is minimized. Only a few publications have addressed the accuracy of 3D systems. McKay et al¹⁸ compared 3D photographic images and CT scans (criterion standard) and found a greater than 0.91 correlation coefficient between measurement by CT and 3D photograph. Furthermore, Schaaf et al⁸ found that the measured CVAI was approximately 2% lower in anthropometric measurements with a caliper than in photographic measurements. In addition, the study measured intrarater (variance of measurements) and interrater (variance of the observers) concordance, and it proved to be excellent. Nevertheless, a 3D photogrammetry is impractical in a private practice clinical setting. It requires space and is cost intensive. The doctor of chiropractic can refer to a craniofacial institution for 3D photographic measurements when an infant’s head shape is worsening or not responding to treatment (Fig 7).

Fig 7.

Three-dimensional evaluation. The yellow-orange and red colors represent volume growth during a treatment with head orthotics, while the gray picture is taken before the treatment. (Copyright: Cranioform, Switzerland). (Color version of figure appears online.)

Radiographic imaging and CT are unacceptable methods in diagnosing, classifying, and monitoring DP. Radiographic imaging and CT expose the patient to radiation and, in a CT, to sedation.¹⁹ It has been shown in different studies that radiation in early childhood can have a negative effect on the intelligence of the patient,¹⁷ and it has the potential to induce malignancy later in life.¹⁸ These methods are only indicated when a true synostosis is suspected.²⁰ Plain skull radiographs of infants are, however, difficult to interpret and might not always give a clear answer.^{21, 22} A craniofacial specialist or another specialist in DP should be able to diagnose DP by clinical examination, but in unusual cases or in patients with a high likelihood of synostosis, a CT is the next diagnostic step.²⁰ Because lambdoid synostosis only occurs in 2% to 3% of patients with posterior plagiocephaly, the indication for a CT is rare.²⁰ For this review, the author did not find any reliability studies on DP measured with radiographic imaging or with a CT.

The evidence shows that anthropometric measurements with a caliper and plagiocephalometry are more reliable as clinical measurement methods than visual assessment and the flexicurve. At present, there is no solid evidence as to which of these 2 measurements, the plagiocephalometry and the anthropometric measurement with a caliper, is the most useful in the diagnosis, classification, and monitoring of DP and brachycephaly. First, more and better quality studies need to be undertaken, and the different measurement techniques need to be compared. The measurement with an anthropometric caliper is easy to apply in clinical practice, taking only a few minutes. The plagiocephalometry takes more time and might be inconvenient in a busy practice. The challenge of both measurement techniques is making accurate measurement of an infant’s head, as it is often in motion. It is very important to use the same clear landmarks for measurements on an infant’s head.

Limitations

This review is limited through a narrative literature search performed by 1 person only. Furthermore, this review is limited to methods in diagnosing, classifying, and monitoring plagiocephaly and brachycephaly. Treatment of those conditions is not part of this review.

Conclusion

Visual assessment, the flexicurve, anthropometric measurement with a caliper, and plagiocephalometry are realistic measurements to use in private practice. Based upon the current evidence from the studies in this review, anthropometric measurements with a caliper and plagiocephalometry are more reliable clinical measurement methods.

Funding Sources and Conflicts of Interest

No funding sources or conflicts of interest were reported for this study.