title: Thoracolumbar spinal ligaments exhibit negative and transverse pre-strain.
abstract: The present work represents the first reported bi-axial spinal ligament pre-strain data for the thoracic and lumbar spine. Ligament pre-strain (in-situ strain) is known to significantly alter joint biomechanics. However, there is currently a lack of comprehensive data with regards to spinal ligament pre-strain. The current work determined the pre-strain of 71 spinal ligaments (30 anterior longitudinal ligaments, 27 supraspinous ligaments and 14 interspinous ligaments). The interspinous ligament and the anterior longitudinal ligament exhibited bi-axial pre-strain distributions, demonstrating they are not uniaxial structures. The supraspinous ligament frequently exhibited large amounts of negative pre-strain or laxity suggesting it makes no mechanical contribution to spinal stability near the neutral posture. Upon implementing multi-axial pre-strain results into a finite element model of the lumbar spine, large differences in spinal biomechanics were observed. These results demonstrate the necessity of accounting for ligament pre-strain in biomechanical models. In addition, the authors present a unique experimental method for obtaining ligament pre-strain that presents a number of advantages when compared to standard techniques.
authors: Brigham Young University, Department of Mechanical Engineering, Provo, UT 84602, USA.
authors: Daniel J
authors: DJ
authors: Robertson
authors: Gregory A
authors: GA
authors: Von Forell
authors: Jeremy
authors: J
authors: Alsup
authors: Anton E
authors: AE
authors: Bowden
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D001835:Body Weight; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008022:Ligaments; D008159:Lumbar Vertebrae; D008297:Male; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae