Computer-aided measurement and grading of cranial asymmetry in children with and without torticollis

UCSQ Method Applied on 3D Photogrammetry: Non-Invasive Objective Differentiation Between Synostotic and Positional Plagiocephaly

OBJECTIVE

Objective differentiation between unilateral coronal synostosis (UCS) and positional posterior plagiocephaly (PPP) based on 3D photogrammetry according to Utrecht Cranial Shape Quantificator (UCSQ).

DESIGN

Retrospective study.

SETTING

Primary craniofacial center.

PATIENTS, PARTICIPANTS

Thirty-two unoperated patients (17 UCS; 15 PPP) (age < 1 year).

INTERVENTIONS

Extraction of variables from sinusoid curves derived using UCSQ: asymmetry ratio forehead and occiput peak, ratio of gradient forehead and occiput peak, location forehead and occiput peak.

MAIN OUTCOME MEASURE(S)

Variables, derived using 3D photogrammetry, were analyzed for differentiation between UCS and PPP.

RESULTS

Frontal peak was shifted to the right side of the head in left-sided UCS (mean x-value 207 [192-220]), and right-sided PPP (mean x-value 210 [200-216]), and to the left in right-sided UCS (mean x-value 161 [156-166]), and left-sided PPP (mean x-value 150 [144-154]). Occipital peak was significantly shifted to the right side of the head in left-sided PPP (mean x-value 338 [336-340]) and to the left in right-sided PPP (mean x-value 23 [14-32]). Mean x-value of occipital peak was 9 (354-30) in left- and 2 (350-12) in right-sided UCS. Calculated ratio of gradient of the frontal peak is, in combination with the calculated asymmetry ratio of the frontal peak, a distinctive finding.

CONCLUSIONS

UCSQ objectively captures shape of synostotic and positional plagiocephaly using 3D photogrammetry, we therefore developed a suitable method to objectively differentiate UCS from PPP using radiation-free methods.

Quantification of Plagiocephaly and Brachycephaly in Infants Using a Digital Photographic Technique

Objectives

The aims of the study were: (1) to develop a technique to quantify plagiocephaly that is safe, accurate, objective, easy to use, well tolerated, and inexpensive; and (2) to compare this method with tracings from a flexicurve ruler.

Design

A case-control study of 31 case infants recruited from outpatient plagiocephaly clinics and 29 control infants recruited from other pediatric outpatient clinics.

Participants

Infants in the study had been diagnosed with nonsynostotic plagiocephaly or brachycephaly and were between 2 and 12 months old.

Interventions

Infants’ head shapes were measured using (a) digital photographs of a head circumference band and (b) a flexicurve ruler. Flexicurve tracings were scanned, and both the digital photos and the scanned flexicurve tracings were analyzed using a custom-written computer program.

Main Outcome Measures

The oblique cranial length ratio was used to quantify cranial asymmetry, and the cephalic index was used to quantify the degree of brachycephaly.

Results

The infants tolerated the photo technique better than the flexicurve. Also, mothers preferred the photo technique. There was less within-subject variance for the photos than for the flexicurve measurements. The results suggested that an oblique cranial length ratio of ≥ 106% can define plagiocephaly and that a cephalic index of ≥ 93% can define brachycephaly.

Conclusions

The photographic technique was better accepted and more repeatable than the flexicurve measuring system. We propose that “normal” head shape is indicated in infants with both an oblique cranial length ratio of less than 106% and a cephalic index of less than 93%.

Head shape measurement standards and cranial orthoses in the treatment of infants with deformational plagiocephaly

This review aims to determine how head shape is measured and describes the use of orthoses in the management of deformational plagiocephaly. A systematic review was conducted and papers published in English up to and including 2006 were sourced from nine databases. After initial screening, 20 papers were included; three literature reviews and 17 original papers. Of the original papers, eight concerned the method of head shape measurement. Measurements are important in determining clinical classification and treatment modality of deformational plagiocephaly. All studies were appraised and assigned a level of evidence according to the Scottish Intercollegiate Guidelines Network. Methodological quality was inadequate. Publications involving the use of cranial orthoses used convenience samples, were not blinded, and used different measurement techniques. No comparison groups were included and participants were not randomized. Evidence suggests that conservative treatments might reduce skull deformity although the quality is poor. Clinical studies investigating the use of cranial orthoses reported beneficial effects. Further research is required to identify the efficacy of cranial orthoses in the treatment of deformational plagiocephaly based on a standardized measurement technique to facilitate classification of this condition.

Plagiocephalometry: a non-invasive method to quantify asymmetry of the skull; a reliability study

Deformational plagiocephaly (DP) in newborns and very young children is a common problem in daily practice. The intrarater and interrater reliability of plagiocephalometry (PCM), a new, non-invasive, inexpensive instrument to assess and quantify the asymmetry of the skull, is evaluated at the outpatient Department of Physical Therapy of the Bernhoven Hospital at Veghel, The Netherlands. Using a thermoplastic material to mould the outline of the infant's skull, a reproduction of the skull shape is performed on paper, allowing for accurate cephalometric measurements. Fifty children (aged 0-24 months), with or without positional preference of the head, and with or without DP, were measured three times by two separate, experienced pediatric physical therapists. Intraclass correlation coefficients (ICC) regarding the measurements of the drawn lines were all above 0.92 (intrarater reliability) and 0.90 (interrater reliability). The ICCs of the plagiocephaly indicators ear deviation (ED), antero-sinistra-antero-dextra (ASAD), postero-dextra-postero-sinistra (PDPS) and oblique diameter difference (ODD) were 0.88, 0.57, 0.92 and 0.96, respectively, for the intrarater reliability and 0.90, 0.65, 0.94 and 0.96, respectively, for the interrater reliability. The ICCs of the two indices oblique diameter difference index (ODDI) and cranial proportional index (CPI) were 0.97 and 0.96, respectively, for the intrarater reliability and 0.95 and 0.92, respectively, for the interrater reliability. The limits of agreement according to Bland Altman, comprising 95% of the differences between two measurements (2 sd), were 4.3 mm (ED), 5.9 mm (ASAD), 3.0 mm (PDPS), 3.4 mm (ODD), 2.7% (ODDI) and 4.5% (CPI) for the intrarater reliability, and 3.7 mm (ED), 5.2 mm (ASAD), 2.4 mm (PDPS), 3.3 mm (ODD), 2.9% (ODDI) and 5.8% (CPI) for the interrater reliability.

CONCLUSION

We conclude that PCM is an easy-to-apply, non-invasive and reliable measurement instrument to assess skull asymmetry with good clinical accuracy and low application costs. PCM might serve as an instrument to be used in all levels of care for children with DP, and might provide information concerning the natural course of DP, as well as the assessment of the effects of conservative treatment strategies on DP.