Apportionment of lumbar intervertebral motion in a standardised flexion and return protocol using fluoroscopy: basic data to improve current spine models
Authors: Breen, A., de Carvalho, D., Wong, A., Kawchuk, G., Funabashi, M. and Swain, M.
Start date: 20 June 2018
The use of fluoroscopy allows for continuous in-vivo intervertebral lumbar spinal motion quantification, the outputs of which are critical to informing musculoskeletal models. Unfortunately, between-study comparisons have been limited due to heterogeneity of data recording methods. Furthermore, recent studies using standardised image acquisition protocols have indicated that the sharing of motion between lumbar levels during bending may be a mechanical marker in low back pain [1,2]. To support future comparative studies, this project aimed to outline a standardised protocol and to identify the apportionment of continuous intervertebral motion for L2-S1 during weight-bearing flexion and return in asymptomatic individuals.
Eighty-one asymptomatic participants (38.5 (21-70) yrs, 28 F) underwent a standardised motion protocol during active weight-bearing flexion and return during low dose fluoroscopic recordings (15fps) from L2-S1. Specifically, participants stood on a motion testing platform (standardised spine placement, bracing the sacrum to resist anteroposterior movement) guided them through a 60° bending arc at 6°/s . Each vertebral body was identified in the first image of the sequence and continuous motion of each lumbar segment was tracked using custom code written in Matlab (V.R2011b). Data from start and end points were truncated to reduce calculation errors according to established methods . The percentage contribution of each lumbar level’s rotation (L2–S1) was calculated for each data point in the motion cycle.
Full data sets were extracted from 78 participants (3 participants’ data were excluded due to image artefacts). Figure 1 shows the average apportionment of motion for all four lumbar levels during flexion (0-50% cycle) and return (50%-100% cycle). Bending and return motion was found to differ, furthermore, high variability of apportionment was noted at all lumbar segments: L2-3 38.1% (SD7.5%), L3-4 30.7% (SD2.8%), L4-5 20.6% (SD4.3%), L5-S1 10.7% (SD4%).