title: Abnormal fetal muscle forces result in defects in spinal curvature and alterations in vertebral segmentation and shape.
abstract: The incidence of congenital spine deformities, including congenital scoliosis, kyphosis, and lordosis, may be influenced by the in utero mechanical environment, and particularly by fetal movements at critical time-points. There is a limited understanding of the influence of fetal movements on spinal development, despite the fact that mechanical forces have been shown to play an essential role in skeletal development of the limb. This study investigates the effects of muscle forces on spinal curvature, vertebral segmentation, and vertebral shape by inducing rigid or flaccid paralysis in the embryonic chick. The critical time-points for the influence of fetal movements on spinal development were identified by varying the time of onset of paralysis. Prolonged rigid paralysis induced severe defects in the spine, including curvature abnormalities, posterior and anterior vertebral fusions, and altered vertebral shape, while flaccid paralysis did not affect spinal curvature or vertebral segmentation. Early rigid paralysis resulted in more severe abnormalities in the spine than later rigid paralysis. The findings of this study support the hypothesis that the timing and nature of fetal muscle activity are critical influences on the normal development of the spine, with implications for the understanding of congenital spine deformities. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2135-2144, 2017.
authors.affiliation: Department of Bioengineering, Imperial College London, Prince Consort Road, SW72AZ, London, United Kingdom.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Rolfe
authors.affiliation: Department of Bioengineering, Imperial College London, Prince Consort Road, SW72AZ, London, United Kingdom.
authors.forename: James H
authors.initials: JH
authors.lastname: Bezer
authors.affiliation: Department of Bioengineering, Imperial College London, Prince Consort Road, SW72AZ, London, United Kingdom.
authors.forename: Tyler
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Bioengineering, Imperial College London, Prince Consort Road, SW72AZ, London, United Kingdom.
authors.forename: Ahmed Z
authors.initials: AZ
authors.lastname: Zaidon
authors.affiliation: Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Oyen
authors.affiliation: Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York 10029.
authors.forename: James C
authors.initials: JC
authors.lastname: Iatridis
authors.affiliation: Department of Bioengineering, Imperial College London, Prince Consort Road, SW72AZ, London, United Kingdom.
authors.forename: Niamh C
authors.initials: NC
authors.lastname: Nowlan
mesh_terms: D000818:Animals; D002642:Chick Embryo; D005324:Fetal Movement; D010243:Paralysis; D013131:Spine / Q000196:embryology*
keywords: chick immobilization; congenital spine deformities; development; flaccid paralysis; muscle forces; rigid paralysis