Obesity and Obesity Shape Markedly Influence Spine Biomechanics: A Subject-Specific Risk Assessment Model

• Published in: Annals of biomedical engineering Vol. 45; no. 10; pp. 2373 - 2382
• Main Authors: Ghezelbash, Farshid, Shirazi-Adl, Aboulfazl, Plamondon, André, Arjmand, Navid, Parnianpour, Mohamad
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2017; Springer Nature B.V
• Subjects: Adiposity; Adolescent; Adult; Aged; Aged, 80 and over; Back pain; Back Pain - pathology; Back Pain - physiopathology; Biochemistry; Biological and Medical Physics; Biomechanical Phenomena; Biomechanics; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Biophysics; Bone mineral density; Classical Mechanics; Compression; Crack propagation; Fatigue; Fatigue failure; Female; Health risks; Humans; Injury analysis; Kinematics; Loads (forces); Lumbar Vertebrae - pathology; Lumbar Vertebrae - physiopathology; Male; Middle Aged; Models, Biological; Obesity; Obesity - pathology; Obesity - physiopathology; Pain; Principal components analysis; Risk assessment; Spine; Stability; Vertebrae; Weight-Bearing; Obesity; Stability; Apple- and pear-shaped; Trunk musculoskeletal model; BMD; Vertebral fracture; Somatotype; Spinal loads
• ISSN: 0090-6964; 1573-9686; 1573-9686
• DOI: 10.1007/s10439-017-1868-7

Underlying mechanisms of obesity-related back pain remain unexplored. Thus, we aim to determine the effect of obesity and its shapes on the spinal loads and the associated risks of injury. Obesity shapes were initially constructed by principal component analysis based on datasets on 5852 obese individuals. Spinal loads, cycles to vertebral failure and trunk stability margin were estimated in a subject-specific trunk model taking account of personalized musculature, passive ligamentous spine, obesity shapes, segmental weights, spine kinematics and bone mineral density. Three obesity shapes (mean and extreme abdominal circumferences) at three body weights (BWs) of 86, 98 and 109 kg were analyzed. Additional BW (12 kg) increased spinal loads by ~11.8%. Higher waist circumferences at identical BW increased spinal forces to the tune of ~20 kg additional BW and the risk of vertebral fatigue compression fracture by 3–7 times when compared with smaller waist circumferences. Forward flexion, greater BW and load in hands increased the trunk stability margin. Spinal loads markedly increased with BW, especially at greater waist circumferences. The risk of vertebral fatigue fracture also substantially increased at greater waist circumferences though not at smaller ones. Obesity and its shape should be considered in spine biomechanics.