title: Microcomputed tomographic analysis of human condyles in unilateral condylar hyperplasia: increased cortical porosity and trabecular bone volume fraction with reduced mineralisation.
abstract: Unilateral condylar hyperplasia or hyperactivity is a disorder of growth that affects the mandible, and our aim was to visualise the 3-dimensional bony microstructure of resected mandibular condyles of affected patients. We prospectively studied 17 patients with a clinical presentation of progressive mandibular asymmetry and an abnormal single-photon emission computed tomographic (SPECT) scan. All patients were treated by condylectomy to arrest progression. The resected condyles were scanned with micro-CT (18 μm resolution). Rectangular volumes of interest were selected in 4 quadrants (lateromedial and superoinferior) of the trabecular bone of each condyle. Variables of bone architecture (volume fraction, trabecular number, thickness, and separation, degree of mineralisation, and degree of structural anisotrophy) were calculated with routine morphometric software. Eight of the 17 resected condyles showed clear destruction of the subchondral layer of cortical bone. There was a significant superoinferior gradient for all trabecular variables. Mean (SD) bone volume fraction (25.1 (6) %), trabecular number (1.69 (0.26) mm(-1)), trabecular thickness (0.17 (0.03) mm), and degree of mineralisation (695.39 (39.83) mg HA/cm(3)) were higher in the superior region. Trabecular separation (0.6 (0.16) mm) and structural anisotropy (1.84 (0.28)) were higher in the inferior region. The micro-CT analysis showed increased cortical porosity in many of the condyles studied. It also showed a higher bone volume fraction, greater trabecular thickness and trabecular separation, greater trabecular number, and less mineralisation in the condyles of the 17 patients compared with the known architecture of unaffected mandibular condyles.
authors.affiliation: Department of Oral and Maxillofacial Surgery/Oral Pathology, VU University Medical Center/Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands. Electronic address: l.karssemakers@vumc.nl.
authors.forename: L H E
authors.initials: LH
authors.lastname: Karssemakers
authors.affiliation: Department of Oral and Maxillofacial Surgery, Academic Medical Center/Emma Childrens' Hospital/Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam, PO-Box 22660, 1100 DD Amsterdam-ZO, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Nolte
authors.affiliation: Department of Oral and Maxillofacial Surgery/Oral Pathology, VU University Medical Center/Academic Center for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
authors.forename: D B
authors.initials: DB
authors.lastname: Tuinzing
authors.affiliation: Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Research Institute MOVE, The Netherlands.
authors.forename: G E J
authors.initials: GE
authors.lastname: Langenbach
authors.affiliation: Department of Nuclear Medicine & PET Research, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands.
authors.forename: P G
authors.initials: PG
authors.lastname: Raijmakers
authors.affiliation: Department of Oral and Maxillofacial Surgery, Academic Medical Center/Emma Childrens' Hospital/Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam, PO-Box 22660, 1100 DD Amsterdam-ZO, The Netherlands.
authors.forename: A G
authors.initials: AG
authors.lastname: Becking
mesh_terms: D000293:Adolescent; D000328:Adult; D016880:Anisotropy; D015519:Bone Density / Q000502:physiology; D002113:Calcification, Physiologic / Q000502:physiology; D002648:Child; D005146:Facial Asymmetry / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D006801:Humans; D006965:Hyperplasia; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008335:Mandibular Condyle / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D009929:Organ Size; D016062:Porosity; D011446:Prospective Studies; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D055114:X-Ray Microtomography / Q000379:methods*; D055815:Young Adult
keywords: Condylar hyperplasia; Facial asymmetry; MicroCT