The Changing Position of the Center of Mass of the Thorax During Growth in Relation to Pre-existent Vertebral Rotation
- PMID: 30395092
- DOI: 10.1097/BRS.0000000000002927
The Changing Position of the Center of Mass of the Thorax During Growth in Relation to Pre-existent Vertebral Rotation
Abstract
Study design: Cross-sectional.
Objective: The aim of this study was to analyze the thoracic center of mass (COM) position of children at different ages and evaluate its relation with the previously reported pre-existent rotational pattern of the normal spine.
Summary of background data: The normal, nonscoliotic thoracic spine is known to have a rotational pattern that changes direction during growth, a transition from left-sided toward right-sided rotation with increasing age. This matches the changing curve convexity seen when idiopathic scoliosis develops at different ages. Furthermore, the direction of pre-existent rotation was shown to be related to organ orientation; in situs inversus the rotation is opposite to situs solitus.
Methods: Computed tomography (CT) scans of the thorax of infantile (0-4 years, n = 40), juvenile (4-10 years, n = 53), and adolescent (10-18 years, n = 62) children without spinal pathology were included from an existing database. The location of the COM inside the thorax was calculated based on Hounsfield-units, representing tissue mass. The COM offset was defined as the shortest distance to the midsagittal plane.
Results: At the infantile age, the COM was 2.5 ± 2.1 mm on the right side, at juvenile age not significantly deviated, and at adolescent age 3.1 ± 2.3 mm on the left side of the midsagittal plane. The mean COM offset correlated linearly with age (r = 0.77, P < 0.001).
Conclusion: The COM shifts from slightly on the right side of the thorax at the infantile age, to neutral at juvenile age, to the left at adolescent age. This corresponds to the earlier demonstrated change in direction of pre-existent rotation in the normal spine with age, as well as with the well-known changing direction, from left to right, of thoracic curve convexity in scoliosis at different ages.
Level of evidence: N/ A.
References
-
- Cheng JC, Castelein RM, Chu WC, et al. Adolescent idiopathic scoliosis. Nat Rev Dis Primers 2015; 1:15030.
-
- Roaf R. The basic anatomy of scoliosis. J Bone Joint Surg Br 1966; 48:786–792.
-
- Liljenqvist UR, Link TM, Halm HF. Morphometric analysis of thoracic and lumbar vertebrae in idiopathic scoliosis. Spine (Phila Pa 1976) 2000; 25:1247–1253.
-
- Thompson SK, Bentley G. Prognosis in infantile idiopathic scoliosis. J Bone Joint Surg Br 1980; 62-B:151–154.
-
- Wynne-Davies R. Familial (idiopathic) scoliosis. A family survey. J Bone Joint Surg Br 1968; 50:24–30.
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