Segmental in vivo vertebral motion during functional human lumbar spine activities

Abstract

Quantitative data on the range of in vivo vertebral motion is critical to enhance our understanding of spinal pathology and to improve the current surgical treatment methods for spinal diseases. Little data have been reported on the range of lumbar vertebral motion during functional body activities. In this study, we measured in vivo 6 degrees-of-freedom (DOF) vertebral motion during unrestricted weightbearing functional body activities using a combined MR and dual fluoroscopic imaging technique. Eight asymptomatic living subjects were recruited and underwent MRI scans in order to create 3D vertebral models from L2 to L5 for each subject. The lumbar spine was then imaged using two fluoroscopes while the subject performed primary flexion-extension, left-right bending, and left-right twisting. The range of vertebral motion during each activity was determined through a previously described imagingmodel matching technique at L2-3, L3-4, and L4-5 levels. Our data revealed that the upper vertebrae had a higher range of flexion than the lower vertebrae during flexionextension of the body (L2-3, 5.4 ± 3.8°; L3-4, 4.3 ± 3.4°; L4-5, 1.9 ± 1.1°, respectively). During bending activity, the L4-5 had a higher (but not significant) range of left-right bending motion (4.7 ± 2.4°) than both L2-3 (2.9 ± 2.4°) and L3-4 (3.4 ± 2.1°), while no statistical difference was observed in left-right twisting among the three vertebral levels (L2-3, 2.5 ± 2.3°; L3-4, 2.4 ± 2.6°; and L4-5, 2.9 ± 2.1°, respectively). Besides the primary rotations reported, coupled motions were quantified in all DOFs. The coupled translation in left-right and anterior-posterior directions, on average, reached greater than 1 mm, while in the proximal-distal direction this was less than 1 mm. Overall, each vertebral level responds differently to flexionextension and left-right bending, but similarly to the leftright twisting. This data may provide new insight into the in vivo function of human spines and can be used as baseline data for investigation of pathological spine kinematics.

Motion characteristics of the vertebral segments with lumbar degenerative spondylolisthesis in elderly patients

“…But the imaging time was about 1 s so that all patients can finish the study. Images were taken as described by previous paper [16].…”

“…The geometry of the dual-orthogonal fluoroscopic system was created in the modeling software [16]. The lumbar vertebrae models were introduced into the virtual system and were independently moved and rotated until their silhouettes matched with those captured on the two orthogonal fluoroscopic images.…”

“…We have developed a combined dual fluoroscopic and MR/CT imaging system (DFIS) to investigate the in vivo lumbar spine kinematics [16]. Using this technique, the 6DOF kinematics of various structures of the vertebrae can be accurately measured when the subjects are at different physiological positions [17].…”

Uneven intervertebral motion sharing is related to disc degeneration and is greater in patients with chronic, non-specific low back pain: an in vivo, cross-sectional cohort comparison of intervertebral dynamics using quantitative fluoroscopy

“…The lumbar spine is a kinetic chain that requires the sharing of motion between levels during bending. Various aspects of intervertebral motion sharing have been investigated in cadaveric studies [17][18][19] in plain radiographic studies in vivo [20][21][22][23][24] and in continuous radiographic studies [3,5,8,20,[25][26][27][28][29][30]. Most of these have studied motion onset and displacement; however, two that studied displacement [4,24] and one that studied pattern variations [29], found differences between patients with CNSLBP and controls.…”

Investigation of coupled bending of the lumbar spine during dynamic axial rotation of the body

“…Altered vertebral motion has been widely assumed as a biomechanical factor causing spinal pathology [1][2][3][4][5]. Therefore, numerous studies have been conducted to understand spinal kinematics using both in vitro and in vivo approaches [2,[6][7][8][9][10][11]. Most cadaveric studies tested motion segments by applying a flexionextension, bending, or axial rotation torque, with or without a compressive load to measure the vertebral motion using various techniques [8,[11][12][13][14][15].…”