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Quantification of plagiocephaly and brachycephaly in infants using a digital photographic technique
B Lynne Hutchison1, Luke A D Hutchison, John M D Thompson
1Department of Pediatrics, University of Auckland, New Zealand. bl.hutchison@auckland.ac.nz
Insights
A new photographic technique accurately quantifies infant plagiocephaly and brachycephaly, proving superior to the flexicurve ruler in infant tolerance and measurement repeatability.
Area of Science:
- Pediatric medicine
- Cranial morphology assessment
- Medical imaging analysis
Background:
- Nonsynostotic plagiocephaly and brachycephaly are common infant head shape deformities.
- Accurate and objective quantification methods are crucial for diagnosis and treatment monitoring.
Purpose of the Study:
- To develop a safe, accurate, objective, and inexpensive method for quantifying infant plagiocephaly.
- To compare the novel technique with the established flexicurve ruler method.
Main Methods:
- A case-control study involving 31 infants with plagiocephaly/brachycephaly and 29 controls (2-12 months old).
- Head shape measurement using digital photographs and flexicurve ruler tracings.
- Analysis via a custom computer program calculating oblique cranial length ratio and cephalic index.
Main Results:
- The photographic technique demonstrated better infant tolerance and higher maternal preference compared to the flexicurve ruler.
- The photographic method exhibited less within-subject variance, indicating greater repeatability.
- An oblique cranial length ratio >= 106% and cephalic index >= 93% were proposed to define plagiocephaly and brachycephaly, respectively.
Conclusions:
- The photographic technique is a more acceptable and repeatable method for quantifying infant head shape deformities.
- This digital method offers a reliable tool for diagnosing and managing plagiocephaly and brachycephaly.
- Normal head shape is defined by an oblique cranial length ratio < 106% and cephalic index < 93%.
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 >or= 106% can define plagiocephaly and that a cephalic index of >or= 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%.
