Creating a normative database of age-specific 3D geometrical data, bone density, and bone thickness of the developing skull: a pilot study.
OBJECTIVE
Finite element models (FEMs) of the head are used to study the biomechanics of traumatic brain injury and depend heavily on the use of accurate material properties and head geometry. Any FEM aimed at investigating traumatic head injury in children should therefore use age-specific dimensions of the head, as well as age-specific material properties of the different tissues. In this study, the authors built a database of age-corrected skull geometry, skull thickness, and bone density of the developing skull to aid in the development of an age-specific FEM of a child's head. Such a database, containing age-corrected normative skull geometry data, can also be used for preoperative surgical planning and postoperative long-term follow-up of craniosynostosis surgery results.


METHODS
Computed tomography data were processed for 187 patients (age range 0-20 years old). A 3D surface model was calculated from segmented skull surfaces. Skull models, reference points, and sutures were processed into a MATLAB-supported database. This process included automatic calculation of 2D measurements as well as 3D measurements: length of the coronal suture, length of the lambdoid suture, and the 3D anterior-posterior length, defined as the sum of the metopic and sagittal suture. Skull thickness and skull bone density calculations were included.


RESULTS
Cephalic length, cephalic width, intercoronal distance, lateral orbital distance, intertemporal distance, and 3D measurements were obtained, confirming the well-established general growth pattern of the skull. Skull thickness increases rapidly in the first year of life, slowing down during the second year of life, while skull density increases with a fast but steady pace during the first 3 years of life. Both skull thickness and density continue to increase up to adulthood.


CONCLUSIONS
This is the first report of normative data on 2D and 3D measurements, skull bone thickness, and skull bone density for children aged 0-20 years. This database can help build an age-specific FEM of a child's head. It can also help to tailor preoperative virtual planning in craniosynostosis surgery toward patient-specific normative target values and to perform objective long-term follow-up in craniosynostosis surgery.
Department of Neurosurgery, Radboud University Medical Center, Nijmegen, The Netherlands;|Division of Experimental Neurosurgery & Neuroanatomy, and.
Hans
H
Delye
Biomechanics Section (BMe), K. U. Leuven; and.
Tim
T
Clijmans
Department of Cranio-Maxillo-Facial surgery, UZ Brussel, Brussels, Belgium.
Maurice Yves
MY
Mommaerts
Biomechanics Section (BMe), K. U. Leuven; and.
Jos Vnder
JV
Sloten
Department of Neurosurgery, Radboud University Medical Center, Nijmegen, The Netherlands;
Jan
J
Goffin
D000293:Adolescent; D017677:Age Distribution; D000704:Analysis of Variance; D015519:Bone Density; D002648:Child; D002675:Child, Preschool; D003393:Cranial Sutures / Q000000981:diagnostic imaging; D016208:Databases, Factual; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010865:Pilot Projects; D012107:Research Design; D017678:Sex Distribution; D012886:Skull / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed; D055815:Young Adult
ANCOVA = analysis of covariance; CI = confidence interval; FEM = finite element model; HU = Hounsfield unit; MANOVA = multivariate analysis of variance; craniofacial; craniosynostosis; finite element model; normative database; skull geometry; skull properties; technique; trauma