Thresholding approaches for estimating paraspinal muscle fat infiltration using T1- and T2-weighted MRI: Comparative analysis using water-fat MRI

Background

Paraspinal muscle fat infiltration is associated with spinal degeneration and low back pain, however, quantifying muscle fat using clinical magnetic resonance imaging (MRI) techniques continues to be a challenge. Advanced MRI techniques, including chemical-shift encoding (CSE) based water-fat MRI, enable accurate measurement of muscle fat, but such techniques are not widely available in routine clinical practice.

Methods

To facilitate assessment of paraspinal muscle fat using clinical imaging, we compared four thresholding approaches for estimating muscle fat fraction (FF) using T1- and T2-weighted images, with measurements from water-fat MRI as the ground truth: Gaussian thresholding, Otsu's method, K-mean clustering, and quadratic discriminant analysis. Pearson's correlation coefficients (r), mean absolute errors, and mean bias errors were calculated for FF estimates from T1- and T2-weighted MRI with water-fat MRI for the lumbar multifidus (MF), erector spinae (ES), quadratus lumborum (QL), and psoas (PS), and for all muscles combined.

Results

We found that for all muscles combined, FF measurements from T1- and T2-weighted images were strongly positively correlated with measurements from the water-fat images for all thresholding techniques (r = 0.70-0.86, p < 0.0001) and that variations in inter-muscle correlation strength were much greater than variations in inter-method correlation strength.

Conclusion

We conclude that muscle FF can be quantified using thresholded T1- and T2-weighted MRI images with relatively low bias and absolute error in relation to water-fat MRI, particularly in the MF and ES, and the choice of thresholding technique should depend on the muscle and clinical MRI sequence of interest.

Opioid Initiation Within One Year After Starting a Digital Musculoskeletal (MSK) Program: An Observational, Longitudinal Study with Comparison Group

Background

In-person, conservative care may decrease opioid use for chronic musculoskeletal (MSK) pain, but the impact of digitally delivered conservative care on opioid use is unknown. This study examines associations between a digital MSK program and opioid initiation and prescriptions among opioid naive adults with chronic MSK pain.

Methods

This observational study used commercial medical and pharmacy claims data to compare digital MSK program members to matched physical therapy (PT) patients. Outcomes were any opioid prescriptions and opioid prescriptions per 100 participants within the 12-months after starting a digital MSK program. After propensity-score matching, we conducted multivariate regression models that controlled for demographic, comorbidity, and baseline MSK healthcare use.

Results

The study included 4195 members and 4195 matched PT patients. For opioid initiation, 7.89% (95% Confidence Interval [CI]: 7.07%, 8.71%) of members had opioid prescriptions within 12 months after starting the digital MSK program versus 13.64% (95% CI: 12.60%, 14.67%) of matched PT patients (p < 0.001). Members had significantly fewer opioid prescriptions (16.73 per 100 participants; 95% CI: 14.11, 19.36) versus PT patients (22.36 per 100 participants; 95% CI: 19.99, 24.73). Members had lower odds (OR: 0.52, 95% CI: 0.45, 0.60) of initiating opioids and significantly fewer prescriptions per 100 participants (beta: -6.40, 95% CI: -9.88, -2.93) versus PT patients after controlling for available confounding factors.

Conclusion

An MSK program that delivers conservative care digitally may be a promising approach for decreasing opioid initiation among individuals with chronic MSK pain given the limitations of the observational design and matching on only available covariates.

Comparison of paraspinal muscle composition measurements using IDEAL fat-water and T2-weighted MR images

PURPOSE

The purpose of this study was to evaluate the agreement between paraspinal muscle composition measurements obtained from fat-water images using % fat-signal fraction (%FSF) in comparison to those obtained from T2-weighted magnetic resonance images (MRI) using a thresholding method.

METHODS

A sample of 35 subjects (19 females, 16 males; 40.26 ± 11.3 years old) was selected from a cohort of patients with chronic low back pain (LBP). Axial T2-weighted and IDEAL (Lava-Flex, 2 echo sequence) fat and water MR images were obtained using a 3.0 Tesla GE scanner. Multifidus, erector spinae, and psoas major muscle composition measurements were acquired bilaterally at L4-L5 and L5-S1 using both imaging sequences and related measurement methods. All measurements were obtained by the same rater, with a minimum of 7 days between each method. Intra-class correlation coefficients (ICCs) were calculated to assess intra-rater reliability. Pearson Correlation and Bland-Altman 95% limits of agreement were used to assess the agreement between both measurement methods.

RESULTS

The intra-rater reliability was excellent for all measurements with ICCs varying between 0.851 and 0.997. Strong positive correlations indicating a strong relationship between composition measurements were obtained from fat-water and T2-weighted images for bilateral multifidus and erector spinae muscles at both spinal levels and the right psoas major muscle at L4-L5, with correlation coefficient r ranging between 0.67 and 0.92. Bland-Altman plots for bilateral multifidus and erector spinae muscles at both levels revealed excellent agreement between the two methods, however, systematic differences between both methods were evident for psoas major fat measurements.

CONCLUSION

Our findings suggest that utilizing fat-water and T2-weighted MR images are comparable for quantifying multifidus and erector spinae muscle composition but not of the psoas major. While this suggests that both methods could be used interchangeably for the multifidus and erector spinae, further evaluation is required to expand and confirm our findings to other spinal levels.

Multi-domain biopsychosocial postoperative recovery trajectories associate with patient outcomes following lumbar fusion

PURPOSE

The purpose of this study is to describe and assess the impact of multi-domain biopsychosocial (BPS) recovery on outcomes following lumbar spine fusion. We hypothesized that discrete patterns of BPS recovery (e.g., clusters) would be identified, and then associated with postoperative outcomes and preoperative patient data.

METHODS

Patient-reported outcomes for pain, disability, depression, anxiety, fatigue, and social roles were collected at multiple timepoints for patients undergoing lumbar fusion between baseline and one year. Multivariable latent class mixed models assessed composite recovery as a function of (1) pain, (2) pain and disability, and (3) pain, disability, and additional BPS factors. Patients were assigned to clusters based on their composite recovery trajectories over time.

RESULTS

Using all BPS outcomes from 510 patients undergoing lumbar fusion, three multi-domain postoperative recovery clusters were identified: Gradual BPS Responders (11%), Rapid BPS Responders (36%), and Rebound Responders (53%). Modeling recovery from pain alone or pain and disability alone failed to generate meaningful or distinct recovery clusters. BPS recovery clusters were associated with number of levels fused and preoperative opioid use. Postoperative opioid use (p < 0.01) and hospital length of stay (p < 0.01) were associated with BPS recovery clusters even after adjusting for confounding factors.

CONCLUSION

This study describes distinct clusters of recovery following lumbar spine fusion derived from multiple BPS factors, which are related to patient-specific preoperative factors and postoperative outcomes. Understanding postoperative recovery trajectories across multiple health domains will advance our understanding of how BPS factors interact with surgical outcomes and could inform personalized care plans.

#OrthoTwitter: Relationship Between Author Twitter Utilization and Academic Impact in Orthopaedic Surgery

Background #OrthoTwitter has evolved to disseminate findings and engage the public. However, the academic impact of Twitter utilization in orthopaedic surgery is unknown. Questions/purposes The purpose of the study was to evaluate relationships between the author and manuscript Twitter activity and citations. Methods Manuscripts in 17 orthopaedic journals from 2018 were identified. Citations, online mentions, impact factors, and subspecialties were obtained. H-index and Twitter account details for authors were obtained for a subset of manuscripts. Relationships between Twitter activity and citations were evaluated. Results 2,473/4,224 (58.5%) manuscripts were mentioned on Twitter (n=29,958 mentions), with Twitter manuscripts cited more frequently (median 10 vs. 7, p<0.0001). Twitter mentions, impact factors, non-open-access status, and subspecialties were associated with citation counts. Articles mentioned in 10, 100, and 1,000 Tweets were observed to have a 1.1-fold, 1.7-fold, and 245-fold increase in citations. In author-level analyses, 156 (20.0%) first and 216 (27.7%) senior authors had Twitter accounts. Citation count was associated with increasing senior author H-index (β _est=0.13, p<0.05), Twitter mentions (β _est=0.0043, p<0.0001), impact factors (β _est=0.13, p<0.0001), and having a first (β _est=0.20, p<0.05) or senior author (β _est=0.17, p<0.05) on Twitter. Articles published in arthroplasty (β _est=0.49, p<0.05), general interest (β _est=0.55, p<0.01), sports (β _est=0.63, p<0.01), and non-open access journals (β _est=0.41, p<0.001) were cited more. H-index correlated with followers for first (rho=0.31, p<0.0001) and senior authors (rho=0.44, p<0.0001). Conclusion Author Twitter utilization is independently associated with manuscript citations. Authors should be aware of the potential association between social media utilization and traditional academic impact. Understanding the relationship between social media utilization and academic impact is necessary to effectively disseminate research.

Spatial distribution of fat infiltration within the paraspinal muscles: implications for chronic low back pain

PURPOSE

Fat infiltration (FI) of the paraspinal muscles (PSMs) measured using MRI is an aspect of muscle quality and is considered to be worse in chronic low back pain (cLBP) patients. However, there is not a clear association between paraspinal muscle FI and cLBP, leaving the clinical importance of paraspinal muscle composition unestablished. The spatial distribution of FI in the PSMs may inform mechanistic understanding of non-specific cLBP as it relates to degenerative intervertebral disc (IVD) pathology. We hypothesized that paraspinal muscle fat-mapping would reveal distinct FI distribution patterns in relation to cLBP symptoms and proximity to symptomatic IVD degeneration.

METHODS

From advanced-sequence water-fat MRI of 40 axial cLBP patients and 21 controls, we examined the spatial distribution of paraspinal muscle FI in relation to the center of rotation at the L4L5 disc. Using statistical parametric mapping, we compared FI patterns for multifidus (MF), erector spinae (ES), and psoas between patients and controls, and to the presence and severity of adjacent degenerative IVD pathology.

RESULTS

The spatial distribution of PSMs FI differs between PSMs and according to symptoms and the adjacent degenerative IVD pathology. Furthermore, the region of MF closest to the disc center of rotation appears most susceptible to FI in the presence of symptomatic IVD degeneration.

CONCLUSION

Our study identified spatial distribution patterns of FI in the PSMs as a potential diagnostic biomarker that may also provide granular mechanistic insights into spine biomechanics related to cLBP, as well as advancing the use of prior summary measures limited to overall muscle FI.

Paraspinal Muscle in Chronic Low Back Pain: Comparison Between Standard Parameters and Chemical Shift Encoding-Based Water-Fat MRI

BACKGROUND

Paraspinal musculature (PSM) is increasingly recognized as a contributor to low back pain (LBP), but with conventional MRI sequences, assessment is limited. Chemical shift encoding-based water-fat MRI (CSE-MRI) enables the measurement of PSM fat fraction (FF), which may assist investigations of chronic LBP.

PURPOSE

To investigate associations between PSM parameters from conventional MRI and CSE-MRI and between PSM parameters and pain.

STUDY TYPE

Prospective, cross-sectional.

POPULATION

Eighty-four adults with chronic LBP (44.6 ± 13.4 years; 48 males).

FIELD STRENGTH/SEQUENCE

3-T, T1-weighted fast spin-echo and iterative decomposition of water and fat with echo asymmetry and least squares estimation sequences.

ASSESSMENT

T1-weighted images for Goutallier classification (GC), muscle volume, lumbar indentation value, and muscle-fat index, CSE-MRI for FF extraction (L1/2-L5/S1). Pain was self-reported using a visual analogue scale (VAS). Intra- and/or interreader agreement was assessed for MRI-derived parameters.

STATISTICAL TESTS

Mixed-effects and linear regression models to 1) assess relationships between PSM parameters (entire cohort and subgroup with GC grades 0 and 1; statistical significance α = 0.0025) and 2) evaluate associations of PSM parameters with pain (α = 0.05). Intraclass correlation coefficients (ICCs) for intra- and/or interreader agreement.

RESULTS

The FF showed excellent intra- and interreader agreement (ICC range: 0.97-0.99) and was significantly associated with GC at all spinal levels. Subgroup analysis suggested that early/subtle changes in PSM are detectable with FF but not with GC, given the absence of significant associations between FF and GC (P-value range: 0.036 at L5/S1 to 0.784 at L2/L3). Averaged over all spinal levels, FF and GC were significantly associated with VAS scores.

DATA CONCLUSION

In the absence of FF, GC may be the best surrogate for PSM quality. Given the ability of CSE-MRI to detect muscle alterations at early stages of PSM degeneration, this technique may have potential for further investigations of the role of PSM in chronic LBP.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 2.

Postoperative Outcomes of a Digital Rehabilitation Program After Total Knee Arthroplasty: Retrospective, Observational Feasibility Study

Background

Surgery can sometimes be the best solution for chronic musculoskeletal pain, but presurgical preparation and postsurgical rehabilitation are often required to achieve the maximum benefits. A digital musculoskeletal surgical care program was developed to support the population of patients undergoing total knee arthroplasty.

Objective

We aimed to demonstrate safety, engagement, and acceptability and explore clinical outcomes, health care use, and satisfaction among participants of a digital musculoskeletal surgical care program who were undergoing total knee arthroplasty.

Methods

A retrospective, observational feasibility study comparing digital musculoskeletal surgical care program participants to a comparison group was conducted. The intervention group registered for a digital musculoskeletal surgical care program, which included health coaches, physical therapists, and tailored exercises and educational articles to provide preoperative and postoperative support to patients who had recently undergone total knee arthroplasty. Comparison group members received standard-of-care treatment. Engagement (number of exercise therapy sessions and educational articles accessed per week) and acceptability (Net Promoter Score) were examined among intervention group participants. Descriptive statistics for postoperative outcomes, including safety (postoperative complications), clinical improvement (pain, function, anxiety, and depression), and health care use and experiences (length of hospital stay, surgery satisfaction, and physical therapy adherence), were reported for both groups. Differences among postoperative results were compared by using the independent samples 2-tailed t test or Mann-Whitney test for continuous outcomes and the Fisher exact test or chi-square test for categorical outcomes.

Results

Of the 53 participants (intervention group: n=22; comparison group: n=31) who were included in this study, 35 (66%) were female and 25 (47%) were aged from 45 to 60 years. On average, the intervention group completed 23 exercise sessions, read 2.7 educational articles, sent 45.5 texts to their health coaches, and were actively engaged for 6 weeks after their operation. Among 21 participants, 14 (67%) self-reported as promoters on the Net Promoter Score scale. Intervention group members reported fewer postoperative complications (6/22, 27%) than the comparison group (15/31, 48%), and they experienced better outcomes with regard to function (Knee Injury and Osteoarthritis Outcome Score–Physical Function Short Form—intervention group: mean 23.0; comparison group: mean 32.5), depression (Patient Health Questionnaire 2-Item—intervention group: mean 0.4; comparison group: mean 1.6), anxiety (General Anxiety Disorder 2-Item—intervention group: mean 0.6; comparison group: mean 1.5), and impressions of change (Patient Global Impression of Change—intervention group: median 7.0; comparison group: median 6.0). Intervention group participants also reported less health care use, better adherence to their physical therapy exercises, and higher surgery satisfaction.

Conclusions

Our digital musculoskeletal surgical care program shows promising levels of engagement and acceptability among those who recently underwent total knee arthroplasty. The surgical care program may also help with improving postsurgical complications and clinical outcomes and lowering health care use.

Influence of patient-specific factors when comparing multifidus fat infiltration between chronic low back pain patients and asymptomatic controls

Introduction

Many studies have attempted to link multifidus (MF) fat infiltration with muscle quality and chronic low back pain (cLBP), but there is no consensus on these relationships.

Methods

In this cross-sectional cohort study, 39 cLBP patients and 18 asymptomatic controls were included. The MF muscle was manually segmented at each lumbar disc level and fat fraction (FF) measurements were taken from the corresponding advanced imaging water-fat images. We assessed the distribution patterns of MF fat from L1L2 to L5S1 and compared these patterns between groups. The sample was stratified by age, sex, body mass index (BMI), subject-reported pain intensity (VAS), and subject-reported low back pain disability (oswestry disability index, ODI).

Results

Older patients had significantly different MF FF distribution patterns compared to older controls (p < 0.0001). Male patients had 34.8% higher mean lumbar spine MF FF compared to male controls (p = 0.0006), significantly different MF FF distribution patterns (p = 0.028), 53.7% higher mean MF FF measurements at L2L3 (p = 0.037), and 50.6% higher mean MF FF measurements at L3L4 (p = 0.041). Low BMI patients had 29.7% higher mean lumbar spine MF FF compared to low BMI controls (p = 0.0077). High BMI patients only had 4% higher mean lumbar spine MF FF compared to high BMI controls (p = 0.7933). However, high BMI patients had significantly different MF FF distribution patterns compared to high BMI controls (p = 0.0324). Low VAS patients did not significantly differ from the control cohort for any of our outcomes of interest; however, high VAS patients had 24.3% higher mean lumbar spine MF FF values (p = 0.0011), significantly different MF FF distribution patterns (p < 0.0001), 34.7% higher mean MF FF at L2L3 (p = 0.040), and 34.6% higher mean MF FF at L3L4 (p = 0.040) compared to the control cohort. Similar trends were observed for ODI.

Conclusions

This study suggests that when the presence of paraspinal muscle fat infiltration is not characteristic of an individual's age, sex, and BMI, it may be associated with lower back pain.

Point-of-care motion capture and biomechanical assessment improve clinical utility of dynamic balance testing for lower extremity osteoarthritis

Musculoskeletal conditions impede patient biomechanical function. However, clinicians rely on subjective functional assessments with poor test characteristics for biomechanical outcomes because more advanced assessments are impractical in the ambulatory care setting. Using markerless motion capture (MMC) in clinic to record time-series joint position data, we implemented a spatiotemporal assessment of patient kinematics during lower extremity functional testing to evaluate whether kinematic models could identify disease states beyond conventional clinical scoring. 213 trials of the star excursion balance test (SEBT) were recorded by 36 subjects during routine ambulatory clinic visits using both MMC technology and conventional clinician scoring. Conventional clinical scoring failed to distinguish patients with symptomatic lower extremity osteoarthritis (OA) from healthy controls in each component of the assessment. However, principal component analysis of shape models generated from MMC recordings revealed significant differences in subject posture between the OA and control cohorts for six of the eight components. Additionally, time-series models of subject posture change over time revealed distinct movement patterns and reduced overall postural change in the OA cohort compared to the controls. Finally, a novel metric quantifying postural control was derived from subject specific kinematic models and was shown to distinguish OA (1.69), asymptomatic postoperative (1.27), and control (1.23) cohorts (p = 0.0025) and to correlate with patient-reported OA symptom severity (R = -0.72, p = 0.018). Time series motion data have superior discriminative validity and clinical utility than conventional functional assessments in the case of the SEBT. Novel spatiotemporal assessment approaches can enable routine in-clinic collection of objective patient-specific biomechanical data for clinical decision-making and monitoring recovery.

Clinical Outcomes After a Digital Musculoskeletal Program for Acute and Subacute Pain: Observational, Longitudinal Study With Comparison Group

Background

Telerehabilitation for musculoskeletal (MSK) conditions may produce similar or better outcomes than usual care, but most telerehabilitation studies address only chronic or postsurgical pain.

Objective

We aimed to examine pain and function at 3, 6, and 12 weeks for individuals with acute and subacute MSK pain who took part in a digital MSK program versus a nonparticipant comparison group.

Methods

We conducted an observational, longitudinal study with a nonparticipant comparison group. The intervention group had video visits with physical therapists who recommended exercise therapies and educational articles delivered via an app. Nonparticipants were those who were registered but unable to participate because their benefit coverage had not yet begun. We collected pain and function outcomes through surveys delivered at 3-, 6-, and 12-week follow-ups. We conducted descriptive analyses, unadjusted regression, and mixed effects regression adjusting for baseline characteristics, time as fixed effects, and a time*group interaction term.

Results

The analysis included data from 675 nonparticipants and 262 intervention group participants. Compared to baseline, the intervention group showed significantly more pain improvement at 3, 6, and 12 weeks versus nonparticipants after adjusting for baseline factors. Specifically, the intervention group’s pain scores decreased by 55.8% at 3 weeks versus baseline, 69.1% at 6 weeks, and 73% at 12 weeks. The intervention group’s adjusted pain scores decreased from 43.7 (95% CI 41.1-46.2) at baseline to 19.3 (95% CI 16.8-21.8) at 3 weeks to 13.5 (95% CI 10.8-16.2) at 6 weeks to 11.8 (95% CI 9-14.6) at 12 weeks. In contrast, nonparticipants’ pain scores decreased by 30.8% at 3 weeks versus baseline, 45.8% at 6 weeks, and 46.7% at 12 weeks. Nonparticipants’ adjusted pain scores decreased from 43.8 (95% CI 42-45.5) at baseline to 30.3 (95% CI 27.1-33.5) at 3 weeks to 23.7 (95% CI 20-27.5) at 6 weeks to 23.3 (95% CI 19.6-27) at 12 weeks. After adjustments, the percentage of participants reporting that pain was better or much better at follow-up was significantly higher by 40.6% at 3 weeks, 31.4% at 6 weeks, and 31.2% at 12 weeks for intervention group participants versus nonparticipants. After adjustments, the percentage of participants with meaningful functional improvement at follow-up was significantly higher by 15.2% at 3 weeks and 24.6% at 12 weeks for intervention group participants versus nonparticipants.

Conclusions

A digital MSK program may help to improve pain and function in the short term among those with acute and subacute MSK pain.

Compensatory biomechanics and spinal loading during dynamic maneuvers in patients with chronic low back pain

Purpose

This study explores the biomechanics underlying the sit-to-stand (STS) functional maneuver in chronic LBP patients to understand how different spinal disorders and levels of pain severity relate to unique compensatory biomechanical behaviors. This work stands to further our understanding of the relationship between spinal loading and symptoms in LBP patients.

Methods

We collected in-clinic motion data from 44 non-specific LBP (NS-LBP) and 42 spinal deformity LBP (SD-LBP) patients during routine clinical visits. An RGB-depth camera tracked 3D joint positions from the frontal view during unassisted, repeated STS maneuvers. Patient-reported outcomes (PROs) for back pain (VAS) and low back disability (ODI) were collected during the same clinical visit.

Results

Between patient groups, SD-LBP patients had 14.3% greater dynamic sagittal vertical alignment (dSVA) and 10.1% greater peak spine torque compared to NS-LBP patients (p < 0.001). SD-LBP patients also had 11.8% greater hip torque (p < 0.001) and 86.7% greater knee torque (p = 0.04) compared to NS-LBP patients. There were no significant differences between patient groups in regard to anterior or vertical torso velocities, but anterior and vertical torso velocities correlated with both VAS (r = − 0.38, p < 0.001) and ODI (r = − 0.29, p = 0.01). PROs did not correlate with other variables.

Conclusion

Patients with LBP differ in movement biomechanics during an STS transfer as severity of symptoms may relate to different compensatory strategies that affect spinal loading. Further research aims to establish relationships between movement and PROs and to inform targeted rehabilitation approaches.

Unsupervised Machine Learning on Motion Capture Data Uncovers Movement Strategies in Low Back Pain

Chronic low back pain (LBP) is a leading cause of disability and opioid prescriptions worldwide, representing a significant medical and socioeconomic problem. Clinical heterogeneity of LBP limits accurate diagnosis and precise treatment planning, culminating in poor patient outcomes. A current priority of LBP research is the development of objective, multidimensional assessment tools that subgroup LBP patients based on neurobiological pain mechanisms, to facilitate matching patients with the optimal therapies. Using unsupervised machine learning on full body biomechanics, including kinematics, dynamics, and muscle forces, captured with a marker-less depth camera, this study identified a forward-leaning sit-to-stand strategy (STS) as a discriminating movement biomarker for LBP subjects. A forward-leaning STS strategy, as opposed to a vertical rise strategy seen in the control participants, is less efficient and results in increased spinal loads. Inefficient STS with the subsequent higher spinal loading may be a biomarker of poor motor control in LBP patients as well as a potential source of the ongoing symptomology.

Clinical outcomes one year after a digital musculoskeletal (MSK) program: an observational, longitudinal study with nonparticipant comparison group

Background

The evidence base for the impact of digital health on musculoskeletal (MSK) outcomes is growing, but it is unclear how much digital MSK programs address pain and function in the intermediate and long term.

Methods

This observational study of digital MSK program participants versus nonparticipants (n = 2570) examined pain, function, depression, and anxiety at 3, 6, and 12 months, and health care use at 12 months. The intervention group engaged in a digital MSK program that included exercise, education, and coaching for at least 3 months. The nonparticipant group registered, but never started the program. We collected data in app or by emailed survey at 3, 6, and 12 months after registering for the program. We conducted descriptive analyses and unadjusted and adjusted regression modeling.

Results

The odds ratio of achieving a minimally clinically important difference (MCID) in pain improvement for the intervention versus the nonparticipant group was 1.97 (95% CI: 1.28, 3.02; p = .002) at 3 months, 1.44 (95% CI: 0.91, 2.25; p = .11) at 6 months, and 2.06 (95% CI: 1.38, 3.08; p = .004) at 12 months in adjusted models. The odds ratio of achieving a MCID in functional improvement for the intervention versus the nonparticipant group was 1.56 (95% CI: 1.03, 2.38; p = .01) at 3 months, 1.55 (95% CI: 1.02, 2.37; p = .04) at 6 months, and 1.35 (95% CI: 0.89, 2.06, p = 0.16) at 12 months in adjusted models. For those with moderate to severe depression or anxiety at baseline, we observed statistically significant lower odds of moderate to severe depression or anxiety at 3 months, 6 months, and 12 months for the intervention versus the nonparticipant group in adjusted models (p < .05). At 12 months, the percentage with invasive, imaging, and conservative services was higher for the nonparticipant versus intervention group by 5.7, 8.1, and 16.7 percentage points, respectively (p < 0.05).

Conclusions

A digital MSK program may offer participants sustained improvement in pain, depression, and anxiety with concomitant decreases in health care use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05188-x.

Paraspinal muscle imaging measurements for common spinal disorders: review and consensus-based recommendations from the ISSLS degenerative spinal phenotypes group

PURPOSE

Paraspinal muscle imaging is of growing interest related to improved phenotyping, prognosis, and treatment of common spinal disorders. We reviewed issues related to paraspinal muscle imaging measurement that contribute to inconsistent findings between studies and impede understanding.

METHODS

Three key contributors to inconsistencies among studies of paraspinal muscle imaging measurements were reviewed: failure to consider possible mechanisms underlying changes in paraspinal muscles, lack of control of confounding factors, and variations in spinal muscle imaging modalities and measurement protocols. Recommendations are provided to address these issues to improve the quality and coherence of future research.

RESULTS

Possible pathophysiological responses of paraspinal muscle to various common spinal disorders in acute or chronic phases are often overlooked, yet have important implications for the timing, distribution, and nature of changes in paraspinal muscle. These considerations, as well as adjustment for possible confounding factors, such as sex, age, and physical activity must be considered when planning and interpreting paraspinal muscle measurements in studies of spinal conditions. Adoption of standardised imaging measurement protocols for paraspinal muscle morphology and composition, considering the strengths and limitations of various imaging modalities, is critically important to interpretation and synthesis of research.

CONCLUSION

Study designs that consider physiological and pathophysiological responses of muscle, adjust for possible confounding factors, and use common, standardised measures are needed to advance knowledge of the determinants of variations or changes in paraspinal muscle and their influence on spinal health.

Automated assessment and classification of spine, hip, and knee pathologies from sit-to-stand movements collected in clinical practice

Efficient, cost-effective methods for quantifying patient biomechanics at the point of care can facilitate faster and more accurate diagnoses. This work presents a new method to diagnose pre-surgical back, hip, and knee patients by analysing their sit-to-stand motion captured by a Kinect camera. Kinematic and dynamic time-series features were extracted from patient movements collected in clinic. These features were used to test a variety of machine learning methods for patient classification. The performance of models trained on time-series features were compared against models trained on domain-knowledge features, highlighting the importance of using time-series data for the classification of human movement. Additionally, the effectiveness of using semi-supervised learning is tested on partially labelled datasets, providing insight on how to boost classification performance in situations where labelled patient data is difficult to obtain. The best semi-supervised model achieves ∼73% accuracy in distinguishing individuals with low-back pain, and hip and knee degeneration from control subjects.

Older Adult Use and Outcomes in a Digital Musculoskeletal (MSK) Program, by Generation

Objective: We investigated use and clinical outcomes in a digital musculoskeletal (MSK) program, by generation.

Method: This longitudinal study uses retrospective data collected online or by app. The study included adults with 12 or more weeks of pain who took part in a digital MSK program. We compared Gen Z and Millennials, Gen X, working age Baby Boomers, and retiree age Baby Boomer and Silent Generation. Program use outcomes were program start, program completion, and number of exercises, educational articles, and messages to coaches. Clinical outcomes were changes in pain, depression, and anxiety from baseline to 12 weeks. We calculated descriptive statistics and conducted adjusted regression models.

Results: Odds of starting the program were significantly higher for Gen Xers (OR: 1.12) and working age Baby Boomers (OR: 1.37) vs. Gen Zers and Millennials. Compared to Gen Zers and Millennials, we observed significantly higher odds of program completion among Gen Xers (OR: 1.62), working age Baby Boomers (OR: 2.24), and retirees (OR: 2.36). Compared to Gen Zers and Millennials, retirees had 19 more exercise sessions (IRR: 1.69), accessed 11 more articles (IRR: 1.84), and sent 4 more messages to coaches (IRR: 1.26). Compared to Gen Z and Millennials, we observed no significant differences in change in pain for Gen Xers, working age Baby Boomers, or retirees.

Conclusions: Adults from multiple generations took part in a digital MSK program. Findings suggest that older generations used a digital MSK program more than younger generations, but had similar pain outcomes.

Intervertebral disc herniation effects on multifidus muscle composition and resident stem cell populations

BACKGROUND

Paraspinal muscles are crucial for vertebral stabilization and movement. These muscles are prone to develop fatty infiltration (FI), fibrosis, and atrophy in many spine conditions. Fibro-adipogenic progenitors (FAPs), a resident muscle stem cell population, are the main contributors of muscle fibrosis and FI. FAPs are involved in a complex interplay with satellite cells (SCs), the primary myogenic progenitor cells within muscle. Little is known about the stem cell composition of the multifidus. The aim of this study is to examine FAPs and SCs in the multifidus in disc herniation patients. Multifidus muscle samples were collected from 10 patients undergoing decompressive spine surgery for lumbar disc herniation. Hamstring muscle was collected from four patients undergoing hamstring autograft ACL reconstruction as an appendicular control. Multifidus tissue was analyzed for FI and fibrosis using Oil-Red-O and Masson's trichrome staining. FAPs and SCs were visualized using immunostaining and quantified with fluorescence-activated cell sorting (FACS) sorting. Gene expression of these cells from the multifidus were analyzed with reverse transcription-polymerase chain reaction and compared to those from hamstring muscle. FI and fibrosis accounted for 14.2%± 7.4% and 14.8%±4.2% of multifidus muscle, respectively. The multifidus contained more FAPs (11.7%±1.9% vs 1.4%±0.2%; P<.001) and more SCs (3.4%±1.6% vs 0.08%±0.02%; P=.002) than the hamstring. FAPs had greater α Smooth Muscle Actin (αSMA) and adipogenic gene expression than FAPs from the hamstring. SCs from the multifidus displayed upregulated expression of stem, proliferation, and differentiation genes.

CONCLUSION

The multifidus in patients with disc herniation contains large percentages of FAPs and SCs with different gene expression profiles compared to those in the hamstring. These results may help explain the tendency for the multifidus to atrophy and form FI and fibrosis as well as elucidate potential approaches for mitigating these degenerative changes by leveraging these muscle stem cell populations.

Digital Care for Chronic Musculoskeletal Pain: 10,000 Participant Longitudinal Cohort Study

BACKGROUND

Chronic musculoskeletal pain has a vast global prevalence and economic burden. Conservative therapies are universally recommended but require patient engagement and self-management to be effective.

OBJECTIVE

This study aimed to evaluate the efficacy of a 12-week digital care program (DCP) in a large population of patients with chronic knee and back pain.

METHODS

A longitudinal observational study was conducted using a remote DCP available through a mobile app. Subjects participated in a 12-week multimodal DCP incorporating education, sensor-guided exercise therapy (ET), and behavioral health support with 1-on-1 remote health coaching. The primary outcome was pain measured by the visual analog scale (VAS). Secondary measures included engagement levels, program completion, program satisfaction, condition-specific pain measures, depression, anxiety, and work productivity.

RESULTS

A total of 10,264 adults with either knee (n=3796) or low back (n=6468) pain for at least three months were included in the study. Participants experienced a 68.45% average improvement in VAS pain between baseline intake and 12 weeks. In all, 73.04% (7497/10,264) participants completed the DCP into the final month. In total, 78.60% (5893/7497) of program completers (7144/10,264, 69.60% of all participants) achieved minimally important change in pain. Furthermore, the number of ET sessions and coaching interactions were both positively associated with improvement in pain, suggesting that the amount of engagement influenced outcomes. Secondary outcomes included a 57.9% and 58.3% decrease in depression and anxiety scores, respectively, and 61.5% improvement in work productivity. Finally, 3 distinct clusters of pain response trajectories were identified, which could be predicted with a mean 76% accuracy using baseline measures.

CONCLUSIONS

These results support the efficacy and scalability of a DCP for chronic low back and knee pain in a large, diverse, real-world population. Participants demonstrated high completion and engagement rates and a significant positive relationship between engagement and pain reduction was identified, a finding that has not been previously demonstrated in a DCP. Furthermore, the large sample size allowed for the identification of distinct pain response subgroups, which may prove beneficial in predicting recovery and tailoring future interventions. This is the first longitudinal digital health study to analyze pain outcomes in a sample of this magnitude, and it supports the prospect for DCPs to serve the overwhelming number of musculoskeletal pain sufferers worldwide.

The Effect of Parity on Age-Related Degenerative Changes in Sagittal Balance

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Evaluate the effects of parity (number of births) on measures of sagittal posture in elderly women. The long-term objective of this study is to identify and mitigate factors contributing to age-related postural deformity in older adults.

SUMMARY OF BACKGROUND DATA

Adult spinal deformity is a prevalent condition that often requires costly surgical management. Females are disproportionately represented in spinal deformity surgical cases with up to 90% of patients being women. The potential contributions of pregnancy on postural degeneration have only begun to be acknowledged and require further study.

METHODS

Two hundred eight women with standing lateral radiographs were selected from the TwinsUK register. Parity information was extracted from questionnaires. Sagittal balance measurements (thoracic kyphosis, lumbar lordosis [LL], pelvic incidence [PI]) were collected and PI-LL mismatch was calculated. One-way analysis of variance tests were done between three separate age categories for measures of sagittal balance and parity and stepwise multivariate regression was done for PI-LL.

RESULTS

Both age and PI-LL mismatch significantly differed between parity categories. PI-LL was on average 7.0° ± 2.5° greater in multiparous (3+ births) subjects than in nulliparous subjects (P < 0.01). Parity did not have an independent relationship with lumbar disc degeneration, lumbar bone mineral density, or any of the individual sagittal balance parameters (P > 0.05 for all), except for PI-LL. From a subanalysis of the effect of parity on sagittal alignment within twin pairs, we found that within pair differences in parity associate with within pair differences in thoracic kyphosis.

CONCLUSION

This study established correlations between measures of spinal curvature in older women and parity for the first time. Longitudinal research is required to establish a causative relationship.

LEVEL OF EVIDENCE

4.

Development of Pelvic Incidence and Lumbar Lordosis in Children and Adolescents

Pelvic incidence (PI) is a measure of the sagittal orientation of the sacrum relative to the acetabula and is not dependent on posture. In asymptomatic adults, PI correlates with lumbar lordosis. Lumbar lordosis is shown to increase with age following the onset of unassisted bipedal locomotion in children, but to what extent PI changes in relation to lumbar lordosis during skeletal maturation is unclear. The purpose of this study is to understand how PI, lumbar lordosis, and age are related in children and adolescents. PI, supine lumbar lordosis (SLL), and individual wedging angles of the lumbar vertebral bodies were measured on mid-sagittal reformatted images from 144 abdominal computed tomographic scans of individuals aged 2-20 years old, divided into three separate age categories representing pre-growth spurt (ages 2-9), growth spurt (10-15), and post-growth spurt (16-20). Our results showed that, while SLL significantly increased with age during development, PI did not. Despite the fact that PI hardly changed with age, the difference between PI and SLL decreased nonlinearly with age. SLL did not correlate with PI in the youngest age category, but positively correlated with PI in the middle and oldest age categories. The relationship between lumbar lordosis and PI, which is correlated in adults, was significant in our older age categories and not in our youngest age category. Our results indicate that PI in children and adolescents may have some predictive value for adult lumbar lordosis. Anat Rec, 302:2132-2139, 2019. © 2019 American Association for Anatomy.

ISSLS PRIZE IN BIOENGINEERING SCIENCE 2019: biomechanical changes in dynamic sagittal balance and lower limb compensatory strategies following realignment surgery in adult spinal deformity patients

STUDY DESIGN

A longitudinal cohort study.

OBJECTIVE

To define a set of objective biomechanical metrics that are representative of adult spinal deformity (ASD) post-surgical outcomes and that may forecast post-surgical mechanical complications. Current outcomes for ASD surgical planning and post-surgical assessment are limited to static radiographic alignment and patient-reported questionnaires. Little is known about the compensatory biomechanical strategies for stabilizing sagittal balance during functional movements in ASD patients.

METHODS

We collected in-clinic motion data from 15 ASD patients and 10 controls during an unassisted sit-to-stand (STS) functional maneuver. Joint motions were measured using noninvasive 3D depth mapping sensor technology. Mathematical methods were used to attain high-fidelity joint-position tracking for biomechanical modeling. This approach provided reliable measurements for biomechanical behaviors at the spine, hip, and knee. These included peak sagittal vertical axis (SVA) over the course of the STS, as well as forces and muscular moments at various joints. We compared changes in dynamic sagittal balance (DSB) metrics between pre- and post-surgery and then separately compared pre- and post-surgical data to controls.

RESULTS

Standard radiographic and patient-reported outcomes significantly improved following realignment surgery. From the DSB biomechanical metrics, peak SVA and biomechanical loads and muscular forces on the lower lumbar spine significantly reduced following surgery (- 19 to - 30%, all p < 0.05). In addition, as SVA improved, hip moments decreased (- 28 to - 65%, all p < 0.05) and knee moments increased (+ 7 to + 28%, p < 0.05), indicating changes in lower limb compensatory strategies. After surgery, DSB data approached values from the controls, with some post-surgical metrics becoming statistically equivalent to controls.

CONCLUSIONS

Longitudinal changes in DSB following successful multi-level spinal realignment indicate reduced forces on the lower lumbar spine along with altered lower limb dynamics matching that of controls. Inadequate improvement in DSB may indicate increased risk of post-surgical mechanical failure. These slides can be retrieved under Electronic Supplementary Material.

Randomized controlled trial of a 12-week digital care program in improving low back pain

Low back pain (LBP) is the leading cause of disability throughout the world and is economically burdensome. The recommended first line treatment for non-specific LBP is non-invasive care. A digital care program (DCP) delivering evidence-based non-invasive treatment for LBP can aid self-management by engaging patients and scales personalized therapy for patient-specific needs. We assessed the efficacy of a 12-week DCP for LBP in a two-armed, pre-registered, randomized, controlled trial (RCT). Participants were included based on self-reported duration of LBP, but those with surgery or injury to the lower back in the previous three months were excluded. The treatment group (DCP) received the 12-week DCP, consisting of sensor-guided exercise therapy, education, cognitive behavioral therapy, team and individual behavioral coaching, activity tracking, and symptom tracking - all administered remotely via an app. The control group received three digital education articles only. All participants maintained access to treatment-as-usual. At 12 weeks, an intention-to-treat analysis showed each primary outcome-Oswestry Disability Index (p < 0.001), Korff Pain (p < 0.001) and Korff Disability (p < 0.001)-as well as each secondary outcome improved more for participants in the DCP group compared to control group. For participants who completed the DCP (per protocol), average improvement in pain outcomes ranged 52-64% (Korff: 48.8-23.4, VAS: 43.6-16.5, VAS impact on daily life: 37.3-13.4; p < 0.01 for all) and average improvement in disability outcomes ranged 31-55% (Korff: 33.1-15, ODI: 19.7-13.5; p < 0.01 for both). Surgical interest significantly reduced in the DCP group. Participants that completed the DCP had an average engagement, each week, of 90%. Future studies will further explore the effectiveness of the DCP for long-term outcomes beyond 12 weeks and for a LBP patient population with possibly greater baseline pain and disability. In conclusion, the DCP resulted in improved LBP outcomes compared to treatment-as-usual and has potential to scale personalized evidence-based non-invasive treatment for LBP patients.

Cross-sectional area of lumbar spinal muscles and vertebral endplates: a secondary analysis of 91 computed tomography images of children aged 2-20

Spinal muscle cross-sectional area has been highly associated with spinal pathology. Despite the medium-high prevalence of spinal pathology in children, there is very limited knowledge regarding muscle size and growth pattern in individuals younger than 20 years of age. The aim of this study is to analyze the change in size and symmetry of spinal muscles (erector spinae, multifidus, psoas and quadratus lumborum) in children 2-20 years of age. We studied reformatted images from 91 abdominal computed tomographic scans of children aged 2-20 years, from an existing imaging dataset. The cross-sectional area of the muscles was bilaterally measured parallel to the upper endplate of the lumbar vertebrae L3-L5 and at true horizontal for S1. The cross-sectional area of the upper vertebral endplate was measured at spinal levels L3-L5. Results were analyzed according to six groups based on children's age: 2-4 years (group 1), 5-7 years (group 2), 8-10 years (group 3), 11-13 years (group 4), 14-16 years (group 5) and 17-20 years (group 6). Vertebral endplate and spinal muscles cross-sectional area increased with age. Two patterns were observed: Endplate, psoas and quadratus lumborum increased up to our 6th oldest age group (17-20), and multifidus and erector spinae reached their largest size in the 5th age group (14-16). The epaxial muscles (erector spinae and multifidus) reached their maximal cross-sectional area before skeletal maturity (18-21 years of age). The hypaxial muscles (psoas and quadratus lumborum) continued to increase in size at least until spinal maturity. Contributing factors for the differences in developmental pattern between the epaxial and hypaxial muscles might include functional, embryological and innervation factors. In conclusion, this research is the first to describe the cross-sectional area of spinal muscles in children. Future longitudinal studies are needed for further understanding of muscle development during childhood and adolescence.

LEVEL OF EVIDENCE

level 2b, Retrospective cohort study.

From the international space station to the clinic: how prolonged unloading may disrupt lumbar spine stability

BACKGROUND CONTEXT

Prolonged microgravity exposure is associated with localized low back pain and an elevated risk of post-flight disc herniation. Although the mechanisms by which microgravity impairs the spine are unclear, they should be foundational for developing in-flight countermeasures for maintaining astronaut spine health. Because human spine anatomy has adapted to upright posture on Earth, observations of how spaceflight affects the spine should also provide new and potentially important information on spine biomechanics that benefit the general population.

PURPOSE

This study compares quantitative measures of lumbar spine anatomy, health, and biomechanics in astronauts before and after 6 months of microgravity exposure on board the International Space Station (ISS).

STUDY DESIGN

This is a prospective longitudinal study.

SAMPLE

Six astronaut crewmember volunteers from the National Aeronautics and Space Administration (NASA) with 6-month missions aboard the ISS comprised our study sample.

OUTCOME MEASURES

For multifidus and erector spinae at L3-L4, measures include cross-sectional area (CSA), functional cross-sectional area (FCSA), and FCSA/CSA. Other measures include supine lumbar lordosis (L1-S1), active (standing) and passive (lying) flexion-extension range of motion (FE ROM) for each lumbar disc segment, disc water content from T2-weighted intensity, Pfirrmann grade, vertebral end plate pathology, and subject-reported incidence of chronic low back pain or disc injuries at 1-year follow-up.

METHODS

3T magnetic resonance imaging and dynamic fluoroscopy of the lumbar spine were collected for each subject at two time points: approximately 30 days before launch (pre-flight) and 1 day following 6 months spaceflight on the ISS (post-flight). Outcome measures were compared between time points using paired t tests and regression analyses.

RESULTS

Supine lumbar lordosis decreased (flattened) by an average of 11% (p=.019). Active FE ROM decreased for the middle three lumbar discs (L2-L3: -22.1%, p=.049; L3-L4: -17.3%, p=.016; L4-L5: -30.3%, p=.004). By contrast, no significant passive FE ROM changes in these discs were observed (p>.05). Disc water content did not differ systematically from pre- to post-flight. Multifidus and erector spinae changed variably between subjects, with five of six subjects experiencing an average decrease 20% for FCSA and 8%-9% for CSA in both muscles. For all subjects, changes in multifidus FCSA strongly correlated with changes in lordosis (r²=0.86, p=.008) and active FE ROM at L4-L5 (r²=0.94, p=.007). Additionally, changes in multifidus FCSA/CSA correlated with changes in lordosis (r²=0.69, p=.03). Although multifidus-associated changes in lordosis and ROM were present among all subjects, only those with severe, pre-flight end plate irregularities (two of six subjects) had post-flight lumbar symptoms (including chronic low back pain or disc herniation).

CONCLUSIONS

We observed that multifidus atrophy, rather than intervertebral disc swelling, associated strongly with lumbar flattening and increased stiffness. Because these changes have been previously linked with detrimental spine biomechanics and pain in terrestrial populations, when combined with evidence of pre-flight vertebral end plate insufficiency, they may elevate injury risk for astronauts upon return to gravity loading. Our results also have implications for deconditioned spines on Earth. We anticipate that our results will inform new astronaut countermeasures that target the multifidus muscles, and research on the role of muscular stability in relation to chronic low back pain and disc injury.

Neural innervation patterns in the sacral vertebral body

PURPOSE

To characterize the distribution of nerves within a single S1 vertebral body, with particular emphasis on the superior endplate that interfaces with the L5/S1 disc.

METHODS

Musculature and connective tissue surrounding the sacrum was carefully dissected away for close visual inspection of penetrating nerve fibers. The S1 vertebral body was then isolated for histology and serial coronal sections were cut and stained with a ubiquitous neural antibody marker (PGP 9.5). Slides were analyzed and nerves were manually marked on high resolution, composite captured images, rendering 3D depictions of internal nerve distribution.

RESULTS

The vast majority of nerves were closely associated with blood vessels within the marrow space with a uniform distribution in both the superior and inferior endplates of the S1 vertebral body. The highest nerve density was seen at the centrum (anatomic center) of the S1 vertebral body with smaller peaks seen at the lateral borders. Nerve fibers were observed branching from anterior sacral nerves and penetrating the lateral border of the S1 (during dissection), corresponding with peaks on nerve density maps.

CONCLUSIONS

Our results demonstrate that the S1 body and endplate are densely innervated and the peak in nerve density at the vertebral center coincides with vasculature patterns previously described in lumbar vertebral bodies. In the sacrum, however, there is no posterior nutrient foramen that facilitates nerve penetration through the vertebral cortex. Rather, our data indicate that nerves penetrate the S1 via the lateral aspects, consistent with being branches of the anterior sacral nerve. Since PGP 9.5 is a ubiquitous neural marker these identified nerves are likely composed of a mixed population of nociceptive and autonomic fibers.

Morphological and postural sexual dimorphism of the lumbar spine facilitates greater lordosis in females

Previous work suggests females are evolutionarily adapted to have greater lumbar lordosis than males to aid in pregnancy load-bearing, but no consensus exists. To explore further sex-differences in the lumbar spine, and to understand contradictions in the literature, we conducted a cross-sectional retrospective study of sex-differences in lumbar spine morphology and sacral orientation. In addition, our sample includes data for separate standing and supine samples of males and females to examine potential sex-differences in postural loading on lumbosacral morphology. We measured sagittal lumbosacral morphology on 200 radiographs. Measurements include: lumbar angle (L1-S1), lumbar vertebral body and disc wedging angles, sacral slope and pelvic incidence. Lumbar angle, representative of lordotic curvature between L1 and S1, was 7.3° greater in females than males, when standing. There were no significant sex-differences in lumbar angle when supine. This difference in standing lumbar angle can be explained by greater lordotic wedging of the lumbar vertebrae (L1-L5) in females. Additionally, sacral slope was greater in females than males, when standing. There were no significant sex-differences in pelvic incidence. Our results support that females have greater lumbar lordosis than males when standing, but not when supine - suggesting a potentially greater range of motion in the female spine. Furthermore, sex-differences in the lumbar spine appear to be supported by postural differences in sacral-orientation and morphological differences in the vertebral body wedging. A better understanding of sex-differences in lumbosacral morphology may explain sex-differences in spinal conditions, as well as promote necessary sex-specific treatments.

Etiology of lumbar lordosis and its pathophysiology: a review of the evolution of lumbar lordosis, and the mechanics and biology of lumbar degeneration

The goal of this review is to discuss the mechanisms of postural degeneration, particularly the loss of lumbar lordosis commonly observed in the elderly in the context of evolution, mechanical, and biological studies of the human spine and to synthesize recent research findings to clinical management of postural malalignment. Lumbar lordosis is unique to the human spine and is necessary to facilitate our upright posture. However, decreased lumbar lordosis and increased thoracic kyphosis are hallmarks of an aging human spinal column. The unique upright posture and lordotic lumbar curvature of the human spine suggest that an understanding of the evolution of the human spinal column, and the unique anatomical features that support lumbar lordosis may provide insight into spine health and degeneration. Considering evolution of the skeleton in isolation from other scientific studies provides a limited picture for clinicians. The evolution and development of human lumbar lordosis highlight the interdependence of pelvic structure and lumbar lordosis. Studies of fossils of human lineage demonstrate a convergence on the degree of lumbar lordosis and the number of lumbar vertebrae in modern Homo sapiens. Evolution and spine mechanics research show that lumbar lordosis is dictated by pelvic incidence, spinal musculature, vertebral wedging, and disc health. The evolution, mechanics, and biology research all point to the importance of spinal posture and flexibility in supporting optimal health. However, surgical management of postural deformity has focused on restoring posture at the expense of flexibility. It is possible that the need for complex and costly spinal fixation can be eliminated by developing tools for early identification of patients at risk for postural deformities through patient history (genetics, mechanics, and environmental exposure) and tracking postural changes over time.

Comparison of vertebral and intervertebral disc lesions in aging humans and rhesus monkeys

OBJECTIVE

To compare gross and histologic patterns of age-related degeneration within the intervertebral disc and adjacent vertebra between rhesus monkeys and humans.

MATERIALS AND METHODS

We examined age-related patterns of disc degeneration from mid-sagittal sections of the intervertebral disc and adjacent vertebral bodies (VB) among six rhesus monkey thoracolumbar and seven human lumbar spines. Gross morphology and histopathology were assessed via the Thompson grading scheme and other degenerative features of the disc and adjacent bone.

RESULTS

Thompson grades ranged from 3 through 5 for rhesus monkey discs (T9-L1) and 2 through 5 for the human discs (T12-S1). In both rhesus monkey and human discs, presence of distinct lesions was positively associated with Thompson grade of the overall segment. Degenerative patterns differed for radial tears, which were more prevalent with advanced disc degeneration in humans only. Additionally, compared to the more uniform anteroposterior disc degeneration patterns of humans, rhesus monkeys showed more severe osteophytosis and degeneration on the anterior border of the vertebral column.

CONCLUSIONS

Rhesus monkey spines evaluated in the present study appear to develop age-related patterns of disc degeneration similar to humans. One exception is the absence of an association between radial tears and disc degeneration, which could reflect species-specific differences in posture and spinal curvature. Considering rhesus monkeys demonstrate similar patterns of disc degeneration, and age at a faster rate than humans, these findings suggest longitudinal studies of rhesus monkeys may be a valuable model for better understanding the progression of human age-related spinal osteoarthritis (OA) and disc degeneration.

Innervation patterns of PGP 9.5-positive nerve fibers within the human lumbar vertebra

Intervertebral disc injury or degeneration is a common cause of low back pain, and yet the specific source of pain remains ambiguous in many cases. Previous research indicates that the central vertebral endplate is highly innervated and can elicit pain responses to pressure. In effort to trace the origin of nerves located at the endplate, we used protein gene product 9.5 (PGP 9.5) to stain neurofibers and then quantified the spatial pattern of nerve distribution within a human L4 lumbar vertebra. The majority of nerves were adjacent to blood vessel walls, and consequently the nerve distribution closely resembled previously established vascularity patterns. We observed that the majority of nerves enter the vertebral body posteriorly, via the basivertebral foramen, and cluster in the vertebral center. These nerves follow the course of the nutrient artery, which enters the vertebral body through the basivertebral foramen, then branches toward the superior and inferior endplates. Our observations support the notion that nerves found at the central endplate could originate from sinuvertebral nerves accompanying the nutrient artery into the vertebral body. We also stained neighboring histological sections with calcitonin gene-related protein and noted significant co-localization with PGP 9.5, substantiating a nociceptive role for the nerves constituting our distribution pattern.

Feasibility and utility of microsatellite markers in archaeological cattle remains from a Viking Age settlement in Dublin

Nineteen cattle bones from the Viking 10th and early 11th century levels in Dublin were assessed for presence of reliable genotypes from three autosomal markers. Due to the good preservational condition of the samples, it was possible to amplify and type at least two out of three of the microsatellite markers (CSRM60, HEL1 and ILSTS001) in 11 specimens. Full three-loci genotypes were obtained from a subset of seven of these samples. A comparative analysis was performed using data from the same three markers in 11 extant British, Irish and Nordic cattle breeds. Although the medieval remains displayed lower levels of diversity than the modern European breeds, the results fit within the ranges obtained from the extant populations. The results indicate a probable origin for the ancient Irish cattle as the remains group significantly more closely with breeds from the British Isles than with those from Scandinavia. The data collected indicate that microsatellites may be useful for the further study of ancient cattle.

Genetic evidence for Near-Eastern origins of European cattle

The limited ranges of the wild progenitors of many of the primary European domestic species point to their origins further east in Anatolia or the fertile crescent. The wild ox (Bos primigenius), however, ranged widely and it is unknown whether it was domesticated within Europe as one feature of a local contribution to the farming economy. Here we examine mitochondrial DNA control-region sequence variation from 392 extant animals sampled from Europe, Africa and the Near East, and compare this with data from four extinct British wild oxen. The ancient sequences cluster tightly in a phylogenetic analysis and are clearly distinct from modern cattle. Network analysis of modern Bos taurus identifies four star-like clusters of haplotypes, with intra-cluster diversities that approximate to that expected from the time depth of domestic history. Notably, one of these clusters predominates in Europe and is one of three encountered at substantial frequency in the Near East. In contrast, African diversity is almost exclusively composed of a separate haplogroup, which is encountered only rarely elsewhere. These data provide strong support for a derived Near-Eastern origin for European cattle.

Ancient DNA suggests a recent expansion of European cattle from a diverse wild progenitor species

A total of 11 Bos primigenius and Bos taurus bones from archaeological sites between 500 and 12000 years old were examined for the presence of DNA. It was possible to amplify and sequence mitochondrial control region DNA extracted from seven of the 11 samples, including two Pleistocene B. primigenius samples. We compared the results with published data by constructing phylogenetic networks. The two B. primigenius samples clustered with the extant B. taurus samples in the networks. The similarity between B. primigenius and modern taurine cattle confirms that these should be considered members of a single species. The sequences obtained from the B. taurus specimens were either identical to the reference sequence for modern European cattle or closely related to it. They included two sequences not previously documented. The network analysis of the ancient data highlights the intermediary nature of the B. primigenius sequences between modern European and African B. taurus and the proximity of the ancient DNA B. taurus sequences to modern European B. taurus. Further analysis of the extant data in the light of the ancient DNA results suggests that a degree of Pleistocene diversity survives in the extant European Bos population that is mainly derived from a more recent population expansion.

Identification of Babesia bovis merozoite surface antigens by using immune bovine sera and monoclonal antibodies

Three Babesia bovis merozoite surface proteins with relative molecular weights of 37,000, 42,000, and 60,000 were identified by indirect immunofluorescence of live merozoites and by immunoprecipitation of 125I-surface-labeled merozoite proteins with immune bovine sera and monoclonal antibodies. These proteins were clearly of parasite origin, as evidenced by immunoprecipitation of metabolically labeled [( 35S]methionine) merozoites from cultures with specific antimerozoite monoclonal antibodies. In addition, two other proteins were identified with these methods. An 85-kilodalton protein was considered to be of parasite origin based on fluorescence reactivity with a monoclonal antibody. However, this protein was not detected after immunoprecipitation of metabolically labeled parasites, and thus, the exact nature of its origin is equivocal. A fifth protein of 145 kilodaltons was detected by immunoprecipitation after metabolic labeling but was not directly apparent on the surfaces of live merozoites. Since merozoite surface proteins may be important in the induction of protective immunity, those identified here are candidates for vaccine studies.

Scanning electron microscopy of isolated Chironomus polytene chromosomes

Individual polytene chromosomes have been isolated from Chironomus stigmaterus for scanning electron microscope observations. The three dimensional ultrastructure of these chromosomes consists of a series of chromatin strands extended in the interbands and more tightly coiled or folded in the banded regions. The nucleolus is observed to be a dense disc or doughnut shaped structure surrounding the chromosome while the Balbiani Rings appear as diffuse regions consisting of both fibrillar and granular elements.