Kinematic variables have been identified as potential biomarkers for low back pain patients; however, an in-depth comparison between chronic (n=22), acute (n=15), and healthy controls (n=136) has not been done. This retrospective data analysis compared intervertebral lumbar motion parameters, angular range of motion, translation, maximum disc height, motion share inequality (MSI) and variability (MSV), and laxity, between these groups. Kinematic parameters were determined using video tracking techniques utilising quantitative fluoroscopy (QF), during both weight-bearing and recumbent controlled sagittal bending tasks. Data was analysed for normality, and appropriate statistical tests were applied to determine differences between groups. There were no significant differences between the groups for age, height, weight and sex. Whilst few differences were found between acute and healthy groups, differences were shown between both chronic and healthy, and acute and chronic groups for all six parameters. Of particular note were examples of differences in the motion share parameters between the acute and chronic populations, with an increased MSI in the chronic group during recumbent flexion, and MSV during recumbent extension, and inversely an increase in MSV in the acute group during weight-bearing flexion.Study purpose and background
Methods and results
Recent research has identified possible functional biomarkers in chronic, nonspecific back pain (CNSLBP) based on intervertebral kinematics. Although excessive IV-RoM is no longer regarded as a clear motion abnormality, some studies have found subtle kinematic measures such as mid-range laxity and motion sharing inequality to be greater in CNSLBP patients. We studied a group of such patients who were investigated following failed interventions in terms of these subtle measures. Thirty-seven patients (mean age 47.5 years SD10.87, F14, M23) with CNSLBP that had recently failed to respond to a range of treatments and 37 healthy controls received passive recumbent lumbar intervertebral flexion assessments following a standardised quantitative fluoroscopy (QF) protocol. Groups were compared for motion sharing inequality (MSI) and variability (MSV) (L2-S1), for level by level laxity and translation, and with reference ranges of these from a separate group of healthy controls (n=54).Purpose and background
Methods
Dynamic measurement of continuous intervertebral motion in low back pain (LBP) research in-vivo is developing. Lumbar motion parameters with the features of biomarkers are emerging and show promise for advancing understanding of personalised biometrics of LBP. However, measurement of changes over time inevitably involve error, due to subjects' natural variation and/or variation in the measurement process. Thus, intra-subject repeatability of parameters to measure changes over time should be established. Seven lumbar spine motion parameters, measured using quantitative fluoroscopy (QF), were assessed for intra-subject repeatability: Intervertebral range-of-motion (IV-RoM), laxity, motion sharing inequality (MSI), motion sharing variability (MSV), flexion translation and flexion disc height. Intra-subject reliability (ICC) and minimal detectable change (MDC95) of baseline and 6-week follow-up measurements were obtained for 109 healthy volunteers (54 coronal and 55 sagittal).Background
Methods
Identifying features in nonspecific low back pain (NSLBP) subjects that distinguish them from controls, or for elucidating subgroups, has proved elusive. Yet these would be helpful to monitor progress, improve management, and understand the nature of the condition. Previous work using quantitative videofluoroscopy (QF) has indicated that the distribution of motion between lumbar intervertebral joints is more uneven in those with a history of NSLBP. However, there maybe other features of these complex motion patterns yet to be revealed. A multivariate analysis was therefore carried out to explore other possible differences. Intervertebral motion data of L2/3 to L4/5, from a previously published study was used. This examined 40 patients with NSLBP and 40 healthy controls, matched for gender, age and body mass index, who underwent passive recumbent QF in the coronal and sagittal planes. For each motion direction, principal components analysis was carried out and salient dimensions selected. Using a lower dimensional principal components (PC) representation, groups were compared using Hoteling's T test. Linear and quadratic discriminant analysis (LDA and QDA) was carried out using PC representations to examine group differences. The features most clearly distinguishing groups from the LDA was examined graphically. An analysis of the sensitivity of the results to the number of PC dimensions was carried out. The performance of the LDA and QDA classifiers were examined using leave-one-out cross-validation.Purpose and background
Methods and results
Despite the rise of back pain disability, objective mechanical assessment is generally lacking. Quantification of intervertebral kinematics using fluoroscopy provides objective measurement, but its use in clinical practice has not been assessed. This study reviewed cases referred to one UK site for lumbar spine quantitative fluoroscopic (QF) examinations and compared the reasons for referral with the findings reported. Fifty-seven consecutive referrals were reviewed. Patients underwent passive recumbent and/or weight-bearing active examinations in either the sagittal or both the sagittal and coronal planes. Data were extracted from anonymised QF reports and analysed for patient characteristics, reason for referral, working diagnosis at referral, level(s) of interest, previous surgical procedures and findings reported. Reports were also thematically analysed for key findings. Most patients had chronic back conditions of moderate or severe intensity. Most (38/57) were male, mean age 47 (SD 13.1) and mean complaint duration 5.4 years (0.3–32 years). They were referred mainly to investigate segmental instability (19/54) or spondylolisthesis (13/54) to inform either surgical referral or conservative management. Instability was reported in only 8/57 cases, but restricted and hypermobile levels in the same patient was also common (13/57). In 11 cases no mechanical abnormality was found.Purpose and Background:
Methods and Results:
To compare static and dynamic lumbar intervertebral ranges of motion (IV-RoM) in patients with chronic, nonspecific low back pain with upper and lower cut off values derived from healthy controls when variability and measurement errors were reduced. Measurements from functional radiographs suffer from high variability and measurement errors, making cut off values for excessive or insufficient motion problematical. This study compared maximum lumbar IV-RoM and maximum IV-RoM at any point in continuous motion sequences in patients with chronic, non-specific back pain with upper and lower cut off values for L2 to L5 from matched controls using quantitative fluoroscopy, where variation and measurement errors were reduced. Participants underwent passive recumbent examinations in the sagittal and coronal planes. Values based on were developed for both maximum and continuous motion in controls (n=40). Fishers exact test was used to analyse proportions of patients whose IV-RoMs exceeded reference values. For maximum IV-RoM in patients, there were no statistically significant differences between groups for the lower value. Only flexion at L4/5 significantly exceeded the upper value (p=0.03). For continuous IV-RoM, left L3/4 (p=0.01) and right L4/5 (p=0.01) were significantly below the lower cut off values. Both flexion L4/5 (p=0.05) and left L3/4 (p=0.01) were significantly above the upper cut off values.Purpose and Background:
Methods and Results:
Investigating inter-vertebral biomechanics in vivo using end-of-range imaging is difficult due to high intra subject variation, measurement errors and insufficient data. Quantitative fluoroscopy (QF) can reliably measure continuous motion but may suffer from contamination from uncontrolled loading and muscle contraction which compromises comparisons between studies and limits interpretation of results. This study presents the methods used to overcome these limitations. Forty chronic, non-specific low back pain (CNSLPB) patients and 40 matched controls underwent QF using a passive recumbent protocol which standardised the rate and range of trunk rotation, thus reducing intra-subject variation and excluding loading and muscle contraction factors. Left, right, flexion and extension were recorded from L2-5 and vertebral motion registered using image processing algorithms, Resultant continuous inter-vertebral rotation data were normalised to produce proportional contributions of each segment throughout the trunk bend The expected continuous proportional contributions at each level and direction were determined by calculating reference intervals (mean +/− 2SD) from controls. Prevalence of patients exceeding these ranges was determined and the association with CNSLBP calculated using Chi-squared analysis. Additionally the variance of the normalised data throughout the continuous motion for each direction was determined and summed to produce an combined number. This was used to measure the difference between patients and controls and entered into ROC curve analysis to investigate discrimination between patients and controls.Background and purpose
Methods and results
A preliminary study to compare continuous sagittal plane lumbar inter-vertebral kinematics in 10 healthy volunteers in recumbent and weight bearing configurations using quantitative fluoroscopy. There are no direct Study Purpose
Background
Four male patients aged 33, 44, 45 and 52 years, who had undergone different spinal stabilisation procedures consisting of flexible stabilisation (DNESYS), posterior instrumented fusion, and anterior interbody fusion with facet fixation were investigated. Images were acquired and analysed in the same way except that a larger number of images (500 per screening) was utilised in each case. Four operated levels and 2 adjacent levels were analysed. All motion patterns were easily distinguishable from those of the normal subjects. The PLIF and DYNESYS stabilisations demonstrated no motion at the instrumented levels. The anterior inter-body fusion-transfacet fixation patient was shown to have developed a pseudarthrosis.
Registration of the images of each vertebra by templates which are automatically tracked and whose output is converted to inter-vertebral kinematic parameters and averaged for display and reporting. Results are currently displayed as inter-vertebral angles throughout the motion that indicate whether or not solid fusion has been achieved. The Instrument Measurement Error is quantifiable and will vary with image quality, but can be improved by averaging. The technology is applicable to any imaging system of sufficient speed and resolution and may, for example, be used with MR in the future.
