Comparison of posteroanterior spinal stiffness measures to clinical and demographic findings at baseline in patients enrolled in a clinical study of spinal manipulation for low back pain

Spinal displacement during thoracic manipulative therapy in mechanical neck pain patients: an observational study

INTRODUCTION

Thoracic manipulative therapy (TMT) is recommended for treating patients with mechanical neck pain (MNP). However, there are multiple proposed recommendations for the mechanism for neck pain reduction.

OBJECTIVE

To investigate displacement of the cervicothoracic spine during the application of TMT in patients with MNP.

METHODS

Thirty-five male patients with MNP were recruited. Displacements of C3, C5, C7, T2, T4 and T6 were measured using a motion capture system while a therapist applied a grade III central posteroanterior TMT (cpa-TMT) to T6.

RESULTS

Mean (SD) displacement ranged from 2.2 (0.62) to 5.5 (1.1) mm. A significant decrease in neck pain intensity at rest was found after the application of the cpa-TMT (mean difference 17 mm, p < 0.001). A downward trend in spinal displacement was noted, with the largest and smallest displacement occurring at T6 and C3, respectively. Correlations between the displacement of T6 and adjacent spinal levels were moderate to high (Pearson's r range 0.70-0.90, p < 0.001). It was showed that cpa-TMT applied to T6 produced the PA displacement toward the upper cervical spine.

CONCLUSION

TMT produces spinal segmental displacements toward the upper cervical spine in MNP patients. These segmental displacements would activate the alleviation effect at both the spinal and supraspinal levels resulting in neck pain reduction. These findings would provide supporting evidence for the use of TMT in neck pain reduction.

Defining and measuring objective and subjective spinal stiffness: a scoping review

PURPOSE

Examine and identify the breadth of definitions and measures of objective and subjective spinal stiffness in the literature, with a focus on clinical implications.

METHODS

A scoping review was conducted to determine what is known about definitions and measures of the specific term of spinal stiffness. Following the framework by Arksey and O'Malley, eligible peer-reviewed studies identified using PubMed, Ebsco health, and Scopus were included if they reported definitions or measures of spinal stiffness. Using a data abstraction form, the studies were classified into four themes: biomechanical, surgical, pathophysiological, and segmental spinal assessment. To identify similarities and differences between studies, sixteen categories were generated.

RESULTS

In total, 2426 records were identified, and 410 met the eligibility criteria. There were 350 measures (132 subjective; 218 objective measures) and 93 indicators of spinal stiffness. The majority of studies (n = 69%) did not define stiffness.

CONCLUSION

This review highlights the breadth of objective and subjective measures that are both clinically and methodologically diverse. There is no consensus regarding a standardised definition of stiffness in the reviewed literature.

The role of an active muscular subsystem in prone instability test during rest and leg raise conditions

BACKGROUND

Clinicians commonly used prone instability test (PIT) by assessing the posterior-to-anterior (PA) displacement to identify lumbar instability. Most studies focusing on passive subsystem found greater mobility in lower lumbar (L4-L5) than upper lumbar (L1-L3) spine. However, there is still a lack of evidence to demonstrate the role of active subsystem. Additionally, it is unclear whether sex affects PA displacements.

AIM

To determine differences in displacement among five lumbar segments, between two testing positions (rest and leg raise), and between male and female during PIT in individuals with chronic non-specific low back pain (CNLBP).

DESIGN

A cross-sectional study design.

SETTING

Spine biomechanics laboratory.

POPULATION

Individuals with CNLBP.

METHODS

An electromagnetic tracking system was used to measure PA displacement with sensors attached at T12, S2 and a hand-held dynamometer. Participants were asked to perform PIT, while a 100N force was applied to each lumbar segment during resting and leg raise positions.

RESULTS

Significantly less PA displacement (P<0.05) was seen in lower compared to upper lumbar spine and in leg raise compared to rest at L1 to L4. No significant interaction of sex with different lumbar levels and conditions (P>0.05) during PIT was found.

CONCLUSIONS

Although previous studies have reported that the lower lumbar spine had greater mobility, the lower amount of displacement during the rest position suggests the role of an active subsystem contributing to lumbar stability regardless of sex.

CLINICAL REHABILTATION IMPACT

A reduction in displacement during the leg raise position across L1 to L4 suggesting an interaction of stabilizing subsystems of the spine to provide lumbar stability.

Sacral Slope Change From Standing to Relaxed-Seated Grossly Overpredicts the Presence of a Stiff Spine

BACKGROUND

Several authors propose that a change in sacral slope of ≤10° between the standing and relaxed-seated positions (ΔSS_{standing→relaxed-seated}) identifies a patient with a stiff lumbar spine and has suggested the use of dual-mobility bearings for such patients undergoing a total hip arthroplasty (THA). The aim of this study was to assess how accurately ΔSS_{standing→relaxed-seated} can identify patients with a stiff spine.

METHODS

A prospective, multicentre, consecutive cohort series of 312 patients had standing, relaxed-seated, and flexed-seated lateral radiographs prior to THA. ΔSS_{standing→relaxed-seated} was determined by the change in sacral slope between the standing and relaxed-seated positions. Lumbar flexion (LF) was defined as the difference in lumbar lordotic angle between standing and flexed-seated. LF ≤20° was considered a stiff spine. The predictive value of ΔSS_{standing→relaxed-seated} for characterizing a stiff spine was assessed.

RESULTS

A weak correlation between ΔSS_{standing→relaxed-seated} and LF was identified (r² = 0.13). Eighty six patients (28%) had ΔSS_{standing→relaxed-seated} ≤10° and 19 patients (6%) had a stiff spine. Of the 86 patients with ΔSS_{standing→relaxed-seated} ≤10°, 13 had a stiff spine. The positive predictive value of ΔSS_{standing→relaxed-seated} ≤10° for identifying a stiff spine was 15%.

CONCLUSION

In this cohort, ΔSS_{standing→relaxed-seated} ≤10° was not correlated with a stiff spine. Using this simplified approach could lead to a 7-fold overprediction of patients with a stiff lumbar spine and abnormal spinopelvic mobility, unnecessary use of dual-mobility bearings, and incorrect component alignment targets. Referring to patients with ΔSS_{standing→relaxed-seated} ≤10° as being stiff is misleading. The flexed-seated position should be used to effectively assess a patient's spine mobility prior to THA.

Efficacy of orthotic support in mitigating low back pain and disability in low back pain sufferers

BACKGROUND

Low back pain (LBP) is a prevalent disabling ailment that affects people all over the world. A wide variety of orthotic designs, ranging from lumbosacral corsets to rigid thermoplastic thoraco-lumbosacral orthosis are used for managing LBP.

OBJECTIVE

Explore and summarize quality literature on the efficacy of orthotic devices in the management of LBP.

METHODS

A systematic review and meta-analysis of the literature on the efficacy of orthosis in low back pain management conducted using electronic databases. Studies utilizing orthotic management alone or combined with other therapies for 2 weeks or above were included. A meta-analysis was performed on primary and secondary variables using Mean difference (MD), Inverse variance (IV), and fixed effect model with 95% CI, Physiotherapy Evidence Database (PEDro) scale, Cochrane Risk of Bias 2 (RoB2) tool were used to assess the quality of evidence and the risk bias.

RESULTS

Out of 14671 studies, only 13 Randomized Controlled Trials (RCT) were deemed eligible for inclusion in this study, all level 1 evidence. We found that orthotics could significantly mitigate LBP (P-value < 0.00001). Similarly, a significant reeducation in LBP-associated disability was observed after orthotic intervention (P-value 0.004).

CONCLUSION

Lumber orthosis plays a significant role in LBP and associated disability mitigations in sufferers of LBP.

Posterior to anterior spinal stiffness measured in a sample of 127 secondary care low back pain patients

BACKGROUND

The sensation of spinal stiffness is a commonly reported symptom among back pain patients, with the clinical assessment of spinal stiffness usually being part of the decision-making process when deciding on providing manual treatment of low back pain. While any relationship between spinal stiffness and low back pain is likely to be multifactorial, prior exploration of this relationship has been overly simplistic (e.g., univariate regression analyses). The purpose of this study was to address this gap by taking a broader approach to compare instrumented measures of spinal stiffness to demographic characteristics, pain phenotypes, psychometrics, and spine-related disability in a sample of secondary care low back pain patients using multivariate regression analysis.

METHODS

Instrumented spinal stiffness measures from 127 patients in secondary care were used to calculate terminal and global spinal stiffness scores. A best subset analysis was used to find the subsets of 14 independent variables that most accurately predicted stiffness based on the evaluation of the adjusted R-square, Akaike Information Criteria, and the Bayesian Information Criteria.

FINDINGS

In the resulting multivariate models, sex (p < 0.001) and age (p < 0.001) were the primary determinants of terminal stiffness, while global stiffness was primarily determined by age (p = 0.003) and disability (p = 0.024).

INTERPRETATION

Instrumented measures of spinal stiffness are multifactorial in nature, and future research into this area should make use of multivariate analyses.

Effects of muscle activity on lumbar spinal stiffness in asymptomatic adults: An investigation using a novel rolling device

BACKGROUND

Device-based measurement of lumbar spinal stiffness has the potential to identify patients with low back pain who are more likely to improve with spinal manipulative therapy. This study evaluates how voluntary contraction of spine muscles may impact stiffness measures.

OBJECTIVE

To determine how the contraction of different spinal muscles may influence spinal stiffness at all lumbar levels.

DESIGN

Experimental study.

METHOD

A mechanical device was used to measure spinal stiffness (N/mm) from L1 to L5 in 12 asymptomatic participants, while muscle activity from four pairs of thoracolumbar muscles was recorded. A baseline measurement was collected with the participants holding their breath at normal exhalation. Participants stiffness was then measured while performing (1) an isometric hip extension, (2) an isometric shoulder flexion, and (3) a deep held inhalation. Mixed-model ANOVAs were used to evaluate the effects of the perturbations on spinal stiffness at each lumbar level. Friedman's test was then computed to evaluate the differences in muscle activity between the perturbations.

RESULTS

Globally, the designed perturbations generated activity in different muscles with different magnitudes (P-values≤0.05). Increased spinal stiffness was observed at each spinal level during the hip extension, and at L5 during the held inhalation (P-values<0.05). A differential effect of the spinal levels on the spinal stiffness was observed during the hip extension and held inhalation (P-values<0.05).

CONCLUSION

This study provides evidence that the magnitude of muscle activity influences spinal stiffness, but not equally between lumbar levels.

A Comparison of Clinical Spinal Mobility Measures to Experimentally Derived Lumbar Spine Passive Stiffness

Spinal stiffness and mobility assessments vary between clinical and research settings, potentially hindering the understanding and treatment of low back pain. A total of 71 healthy participants were evaluated using 2 clinical assessments (posteroanterior spring and passive intervertebral motion) and 2 quantitative measures: lumped mechanical stiffness of the lumbar spine and local tissue stiffness (lumbar erector spinae and supraspinous ligament) measured via myotonometry. The authors hypothesized that clinical, mechanical, and local tissue measures would be correlated, that clinical tests would not alter mechanical stiffness, and that males would demonstrate greater lumbar stiffness than females. Clinical, lumped mechanical, and tissue stiffness were not correlated; however, gradings from the posteroanterior spring and passive intervertebral motion tests were positively correlated with each other. Clinical assessments had no effect on lumped mechanical stiffness. The males had greater lumped mechanical and lumbar erector spinae stiffness compared with the females. The lack of correlation between clinical, tissue, and lumped mechanical measures of spinal stiffness indicates that the use of the term "stiffness" by clinicians may require reevaluation; clinicians should be confident that they are not altering mechanical stiffness of the spine through segmental mobility assessments; and greater resting lumbar erector stiffness in males suggests that sex should be considered in the assessment and treatment of the low back.

Analysis of Surgical Forces Required to Gain Access Using a Probe for Minimally Invasive Spine Surgery via Cadaveric-Based Experiments Towards Use in Training Simulators

INTRODUCTION

Virtual Reality haptic-based surgical simulators for training purposes have recently been receiving increased traction within the medical field. However, its future adoption is contingent on the accuracy and reliability of the haptic feedback.

GOAL

This study describes and analyzes the implementation of a set of haptic-tailored experiments to extract the force feedback of a medical probe used in minimally invasive spinal lumbar interbody fusion surgeries.

METHODS

Experiments to extract linear, lateral and rotational insertion, relaxation and extraction of the tool within the spinal muscles, intervertebral discs and lumbar nerve on two cadaveric torsos were conducted.

RESULTS

Notably, mean force-displacement and torque-angular displacement curves describing the different tool-tissue responses were reported with a maximum force of 6.87 (±1.79) N at 40 mm in the muscle and an initial rupture force through the Annulus Fibrosis of 20.550 (±7.841) N at 6.441 mm in the L₄/L₅ disc.

CONCLUSION

The analysis showed that increasing the velocity of the probe slightly reduced and delayed depth of the muscle punctures but significantly lowered the force reduction due to relaxation. Decreasing probe depth resulted with a reduction to the force relaxation drop. However, varying the puncturing angle of attack resulted with a significant effect on increasing force intensities. Finally, not resecting the thoracolumbar fascia prior to puncturing the muscle resulted with a significant increase in the force intensities.

SIGNIFICANCE

These results present a complete characterization of the input required for probe access for spinal surgeries to provide an accurate haptic response in training simulators.

Influence of body position and axial load on spinal stiffness in healthy young adults

PURPOSE

This study aimed at investigating the effects of different body positions and axial loads on spinal stiffness to better understand spinal stabilisation mechanisms.

METHODS

The posterior-to-anterior lumbar and thoracic spinal stiffness of 100 young healthy adults (mean age 23 years; 50 females) were measured in three test situations: prone, standing and standing while carrying a load equal to 50% of the subject's body weight. Each test situation comprised three trials.

RESULTS

Spinal stiffness in all test situations showed good reliability. Repeated measures analysis of covariance showed significantly higher spinal stiffness in standing than in the prone position [F(1/1694) = 433.630, p < 0.001]. However, spinal stiffness was significantly lower when standing while carrying a load of 50% of the body weight than when standing without additional load [F(1/1494) = 754.358, p < 0.001].

CONCLUSION

This study showed that spinal lumbar and thoracic stiffness increases when body position is changed from prone to standing. Additional axial load of 50% of the subject's body weight results in reduced spinal stiffness during standing. These slides can be retrieved under Electronic Supplementary Material.

Association of lumbar spine stiffness and flexion-relaxation phenomenon with patient-reported outcomes in adults with chronic low back pain - a single-arm clinical trial investigating the effects of thrust spinal manipulation

Background

Spinal manipulation (SM) is used commonly for treating low back pain (LBP). Spinal stiffness is routinely assessed by clinicians performing SM. Flexion-relaxation ratio (FRR) was shown to distinguish between LBP and healthy populations. The primary objective of this study was to examine the association of these two physiological variables with patient-reported pain intensity and disability in adults with chronic LBP (>12 weeks) receiving SM.

Methods

A single-arm trial provided 12 sessions of side-lying thrust SM in the lumbosacral region over 6 weeks. Inclusion criteria included 21–65 years old, Roland-Morris Disability Questionnaire (RMDQ) score ≥ 6 and numerical pain rating score ≥ 2. Spinal stiffness and FRR were assessed pre-treatment at baseline, after 2 weeks and after 6 weeks of treatment. Lumbar spine global stiffness (GS) were calculated from the force-displacement curves obtained using i) hand palpation, ii) a hand-held device, and iii) an automated indenter device. Lumbar FRR was assessed during trunk flexion-extension using surface electromyography. The primary outcomes were RMDQ and pain intensity measured by visual analog scale (VAS). Mixed-effects regression models were used to analyze the data.

Results

The mean age of the 82 participants was 45 years; 48% were female; and 84% reported LBP >1 year. The mean (standard deviation) baseline pain intensity and RMDQ were 46.1 (18.1) and 9.5 (4.3), respectively. The mean reduction (95% confidence interval) after 6 weeks in pain intensity and RMDQ were 20.1 mm (14.1 to 26.1) and 4.8 (3.7 to 5.8). There was a small change over time in the palpatory GS but not in the hand-held or automated GS, nor in FRR. The addition of each physiologic variable did not affect the model-estimated changes in VAS or RMDQ over time. There was no association seen between physiological variables and LBP intensity. Higher levels of hand-held GS at L3 and automated GS were significantly associated with higher levels of RMDQ (p = 0.02 and 0.03, respectively) and lower levels of flexion and extension FRR were significantly associated with higher levels of RMDQ (p = 0.02 and 0.008, respectively) across the 3 assessment time points.

Conclusions

Improvement in pain and disability observed in study participants with chronic LBP was not associated with the measured GS or FRR.

Trial registration

NCT01670292 on clinicaltrials.gov, August 2, 2012

Does experimental low back pain change posteroanterior lumbar spinal stiffness and trunk muscle activity? A randomized crossover study

BACKGROUND

While some patients with low back pain demonstrate increased spinal stiffness that decreases as pain subsides, this observation is inconsistent. Currently, the relation between spinal stiffness and low back pain remains unclear. This study aimed to investigate the effects of experimental low back pain on temporal changes in posteroanterior spinal stiffness and concurrent trunk muscle activity.

METHOD

In separate sessions five days apart, nine asymptomatic participants received equal volume injections of hypertonic or isotonic saline in random order into the L3-L5 interspinous ligaments. Pain intensity, spinal stiffness (global and terminal stiffness) at the L3 level, and the surface electromyographic activity of six trunk muscles were measured before, immediately after, and 25-minute after injections. These outcome measures under different saline conditions were compared by generalized estimating equations.

FINDINGS

Compared to isotonic saline injections, hypertonic saline injections evoked significantly higher pain intensity (mean difference: 5.7/10), higher global (mean difference: 0.73N/mm) and terminal stiffness (mean difference: 0.58N/mm), and increased activity of four trunk muscles during indentation (P<0.05). Both spinal stiffness and trunk muscle activity returned to baseline levels as pain subsided.

INTERPRETATION

While previous clinical research reported inconsistent findings regarding the association between spinal stiffness and low back pain, our study revealed that experimental pain caused temporary increases in spinal stiffness and concurrent trunk muscle co-contraction during indentation, which helps explain the temporal relation between spinal stiffness and low back pain observed in some clinical studies. Our results substantiate the role of spinal stiffness assessments in monitoring back pain progression.

The effect of application site of spinal manipulative therapy (SMT) on spinal stiffness

BACKGROUND CONTEXT

Like other factors that can influence treatment efficacy (eg, dosage, frequency, time of day), the site of treatment application is known to affect various physical interventions such as topical anesthetics and cardiopulmonary resuscitation. Like these examples, spinal manipulative therapy (SMT) is a physical intervention that may exhibit maximal benefit when directed to a specific site. Whereas numerous studies of SMT efficacy have produced mixed results, few studies have taken into account the site of SMT application.

PURPOSE

To determine if the site of SMT application modulates the effect of SMT in an anesthetized feline model.

STUDY DESIGN

Spinal manipulative therapy applied to specific anatomic locations randomized in a Latin square design with a no-SMT control.

OUTCOME MEASURES

Physiologic measures (spinal stiffness).

METHODS

Simulated SMT was delivered by a validated mechanical apparatus to the intact lumbar spine of eight anesthetized felines at four unique sites: L6 spinous process, left L6 lamina, left L6 mammillary process, and L7 spinous process. To measure spinal stiffness, a separate indentation load was applied mechanically to the L6 spinous process before and after each SMT application. Spinal stiffness was calculated from the resulting force-displacement curve as the average stiffness (k) and terminal instantaneous stiffness (TIS).

RESULTS

Relative to the no-SMT control, significant decreases in spinal stiffness followed the SMT when L6 spinous and L6 lamina were used as the contact site. Terminal instantaneous stiffness significantly decreased -0.48 N/mm (upper, lower 95% confidence interval [-0.86, -0.09]) with L6 spinous as the contact site and decreased -0.44 N/mm (-0.82, -0.05), with the L6 lamina as the contact site. k increased 0.44 N/mm (-0.01, 088), using L6 spinous as the contact site.

CONCLUSIONS

Decreases in terminal spinal stiffness were observed after SMT delivered at some application sites but not the others. The results suggest that SMT contact site modulates SMT's effect on spinal stiffness in a feline model. Changes in spinal terminal instantaneous spinal stiffness were similar in magnitude and direction to those observed in symptomatic human subjects who report benefits after SMT.

A randomized clinical trial comparing extensible and inextensible lumbosacral orthoses and standard care alone in the management of lower back pain

STUDY DESIGN

Single blinded, randomized clinical trial for the evaluation of lumbosacral orthoses (LSOs) in the management of lower back pain (LBP).

OBJECTIVE

To evaluate the effects of two types of LSOs on self-rated disability in patients with LBP.

SUMMARY OF BACKGROUND DATA

LSOs are commonly used for the management of LBP, but their effectiveness may vary because of design. An inextensible LSO (iLSO) reduces trunk motion and increases trunk stiffness, whereas an extensible LSO (eLSO) does not.

METHODS

A total of 98 participants with LBP were randomized to 3 groups: (1) standard care (SC) group, which included medication and physical therapy (n = 29), (2) SC with eLSO (eLSO group) (n = 32), and (3) SC with iLSO (iLSO group) (n = 37). Outcome measures were evaluated before and after 2 weeks of treatment: modified Oswestry Disability Index (ODI), Patient Specific Activity Scale, pain ratings, and Fear Avoidance Beliefs Questionnaire.

RESULTS

There were no statistically significant differences between groups at baseline. Compared with the SC alone, iLSO group showed greater improvement on the ODI scores (P = 0.01) but not the eLSO group. The ODI scores improved by a mean of 2.4 (95% confidence interval [CI], 2.2-7.1), 8.1 (95% CI, 2.8-13.4), and 14.0 (95% CI, 8.2-19.8) points for SC, eLSO, and iLSO groups, respectively. Individuals wearing the iLSO had 4.7 times higher odds of achieving 50% or greater improvement in the ODI scores than those assigned to SC (95% CI, 1.2-18.5, P = 0.03). Both the eLSO and iLSO groups had a greater improvement in the Patient Specific Activity Scale scores than the SC group (P = .05 and P = 0.01, respectively), but the change did not meet the minimal clinically important difference. Pain ratings improved for all 3 groups, with no statistical difference between them. Finally, no significant differences across groups were found for the Fear Avoidance Beliefs Questionnaire.

CONCLUSION

An iLSO led to greater improvement in ODI scores than SC and an eLSO. We surmise that the likely mechanism responsible for this difference in outcome was the added trunk stiffness and motion restriction by the iLSO.

LEVEL OF EVIDENCE

2.

Study protocol for patient response to spinal manipulation - a prospective observational clinical trial on physiological and patient-centered outcomes in patients with chronic low back pain

Background

Low back pain (LBP) is a major health issue due to its high prevalence rate and socioeconomic cost. While spinal manipulation (SM) is recommended for LBP treatment by recently published clinical guidelines, the underlying therapeutic mechanisms remain unclear. Spinal stiffness is routinely examined and used in clinical decisions for SM delivery. It has also been explored as a predictor for clinical improvement. Flexion-relaxation phenomenon has been demonstrated to distinguish between LBP and healthy populations. The primary objective of the current study is to collect preliminary estimates of variability and effect size for the associations of these two physiological measures with patient-centered outcomes in chronic LBP patients. Additionally biomechanical characteristics of SM delivery are collected with the intention to explore the potential dose–response relationship between SM and LBP improvement.

Methods/Design

This is a prospective, observational study applying side-lying, high velocity, low amplitude SM as treatment for patients with LBP over a course of 6 weeks. Approximately 80 participants will be enrolled if they present with chronic LBP of 1, 2 or 3 in Quebec Task Force Classification for spinal disorders, a Roland-Morris Disability Questionnaire (RMDQ) score ≥ 6, and persistent LBP ≥ 2 with a maximum ≥ 4 using numerical rating scale. Patient-centered outcomes include LBP using visual analog scale, RMDQ, and PROMIS-29. Lumbar spine stiffness is assessed using palpation, a hand-held instrumented device, and an automated device. Flexion-relaxation is assessed using surface electromyography at the third level of the lumbar spine. Biomechanical characteristics of SM are assessed using a self-reported, itemized description system, as well as advanced kinetic measures that will be applied to estimate forces and moments at the lumbar segment level targeted by SM.

Discussion

Beside alterations in material properties of the passive components of the spine, increased neuromuscular activity may also contribute to a stiffened spine. Examining changes in both spinal stiffness and flexion-relaxation along the course of the treatment provides an opportunity to understand if the therapeutic effect of SM is associated with its action on active and/or passive components of the spine.

Trial registration

NCT01670292 on clinicaltrials.gov.

The persistence of lumbar somatic dysfunction and its association with bone mineral density

CONTEXT

Clinically meaningful somatic dysfunction, if left untreated, should persist over time and be associated with objective measurable findings.

OBJECTIVE

To investigate the persistence of lumbar somatic dysfunction over 8 weeks and the association of that persistence with lumbar bone mineral density (BMD) T scores.

METHODS

Individuals were assessed at 0, 4, and 8 weeks for the presence and severity of paraspinal tissue texture abnormalities (TTA), vertebral rotational asymmetry, anterior motion restriction, and tenderness from L1 to L4. Participants underwent dual-energy x-ray absorptiometry of the lumbar spine at 0 and 8 weeks. Persistent somatic dysfunction findings from all 3 examinations were compared with BMD T scores obtained at 8 weeks and to changes in the BMD T scores from 0 to 8 weeks.

RESULTS

Forty-eight individuals (38 women [79%] and 10 men [21%]) participated in the study. The mean (standard deviation [SD]) age was 30.1 (6.4) years (range, 20.0-40.8 years), and the mean (SD) body mass index was 26.3 (5.2). The percentage of vertebrae with persistent somatic dysfunction varied by vertebral level and ranged from 44% to 83% for TTA, 63% to 79% for rotational asymmetry, 10% to 56% for motion restriction, and 2% to 10% for tenderness. Vertebral segments with persistent motion restriction had higher mean BMD T scores (95% confidence interval [CI]) than those without persistent motion restriction (0.6 [0.4 to 0.8] vs 0.2 [0.1 to 0.4], respectively; P=.02). There was a significant increase in the vertebral BMD T scores for those vertebrae that demonstrated persistent TTA (P=.02) and for those vertebrae that demonstrated persistent moderate/severe TTA (P=.02). A significant difference was found in the initial to final vertebral BMD T-score change between vertebrae that demonstrated persistent tenderness and those that did not (mean [95% CI] change, -0.2 [-0.4 to 0.1] vs 0.1 [0.0 to 0.1], respectively; P=.04).

CONCLUSION

A persistence of predominantly left lumbar rotation was observed. Persistent vertebral motion restriction was shown to have an association with final lumbar BMD T scores, and persistent TTA and tenderness were associated with changes in the BMD T scores over 8 weeks.

Publication rates of abstracts presented at the Association of Chiropractic Colleges Educational Conference/Research Agenda Conference from 2002 to 2008

Objective : The purposes of this study were to investigate the overall publication rates of presentations at the Association of Chiropractic Colleges Educational Conference/Research Agenda Conference (ACC/RAC) meetings (2002-2008), differences in the publication rates of platform vs poster presentations, and the consistency of the meeting abstract compared to the full-length journal article. Methods : Abstracts were obtained from proceedings published in the Journal of Chiropractic Education. Literature searches using PubMed and the Index to the Chiropractic Literature (ICL) were performed to locate peer-reviewed journal articles based upon those abstracts. Whether the article was based upon a poster or platform presentation, and the congruence of the information in the abstract and article were recorded. Results : We identified 776 proceeding abstracts, 249 of which eventually were published between 2002 and 2012. The overall publication rate was 32.2%. A total of 42.7% of platform presentations eventually were published vs 20.3% of posters. Congruency showed that 43.2% had the same title as the meeting abstract, 59.7% had the same authorship, and 88.8% had the same methods. Conclusion : Publication rates of abstracts from spine and orthopedic surgery national meetings range from 34% to 59%. The ACC/RAC meetings have similar publication rates. More platform than poster presentations reach full publication. The congruency of ACC/RAC abstracts to published articles is higher than national meetings in other fields.

Within- and between-day reliability of spinal stiffness measurements obtained using a computer controlled mechanical indenter in individuals with and without low back pain

Instrumented spinal stiffness measurements have shown high test-retest reliability. However, factors that may affect reliability have yet to be investigated. The objective of this study was to compare the: 1) within- and between-day reliability of a mechanical indentation device (MID) in measuring spinal stiffness, 2) measurement precision of averaging multiple measurements, and 3) reliability of stiffness measurements between individuals with and without low back pain (LBP). The spinal stiffness of 26 volunteers with and without LBP was measured 3 times by MID in each of two visits 1-4 days apart. Two stiffness measures were calculated from the resulting force-displacement data: global stiffness and terminal stiffness. Intraclass correlation coefficients (ICCs) were used to estimate reliability. Measurement precision was measured by minimal detectable changes, bias and 95% limits of agreement. Using the mean of three spinal stiffness measurements, the measurement precision was improved by 33.7% over a single measurement. Averaging three measurements, the within- and between-day reliability point estimates of both global and terminal stiffness were 0.99 and 0.98, respectively. The reliability estimates of spinal stiffness measurement using MID were not significantly altered by the participants' LBP status across all circumstances (95% confidence intervals overlapped). With our experimental protocol, averaging three spinal stiffness measurements using MID produces reliable stiffness measurements regardless of individuals' LBP status.

A structured review of spinal stiffness as a kinesiological outcome of manipulation: its measurement and utility in diagnosis, prognosis and treatment decision-making

PURPOSE

To review and discuss the methods used for measuring spinal stiffness and factors associated with stiffness, how stiffness is used in diagnosis, prognosis, and treatment decision-making and the effects of manipulative techniques on stiffness.

METHODS

A systematic search of MEDLINE, EMBASE, CINAHL, AMED and ICL databases was conducted. Included studies addressed one of four constructs related to stiffness: measurement, diagnosis, prognosis and/or treatment decision-making, and the effects of manipulation on stiffness. Spinal stiffness was defined as the relationship between force and displacement.

RESULTS

One hundred and four studies are discussed in this review, with the majority of studies focused on the measurement of stiffness, most often in asymptomatic persons. Eight studies investigated spinal stiffness in diagnosis, providing limited evidence that practitioner-judged stiffness is associated with radiographic findings of sagittal rotational mobility. Fifteen studies investigated spinal stiffness in prognosis or treatment decision-making, providing limited evidence that spinal stiffness is unlikely to independently predict patient outcomes, though stiffness may influence a practitioner's application of non-thrust manipulative techniques. Nine studies investigating the effects of manipulative techniques on spinal stiffness provide very limited evidence that there is no change in spinal stiffness following thrust or non-thrust manipulation in asymptomatic individuals and non-thrust techniques in symptomatic persons, with only one study supporting an immediate, but not sustained, stiffness decrease following thrust manipulation in symptomatic individuals.

CONCLUSIONS

The existing limited evidence does not support an association between spinal stiffness and manipulative treatment outcomes. There is a need for additional research investigating the effects of manipulation on spinal stiffness in persons with spinal pain.

Posteroanterior spinal stiffness at T5, T10, and L3 levels in normal subjects

OBJECTIVE

To measure, by using standardized device and protocol, posteroanterior (PA) spinal stiffness at the 5th and 10th thoracic (T5 and T10) and 3rd lumbar (L3) vertebral levels in asymptomatic adult volunteers.

DESIGN

A cross-sectional study.

SETTING

Osteopathic Heritage Foundation Physical Medicine Core Research Laboratory where the Therapeutic Spinal Mobilizer was fabricated to standardize the testing protocol.

PARTICIPANTS

Sixteen asymptomatic adult volunteers.

METHODS

Volunteers were in the prone position on the treatment plinth and the loading block of the loading piston was placed at T5, T10, and L3. The subjects were instructed to remain still, to not contract any muscle, and to stop breathing mid cycle for 15 seconds when the data acquisition was initiated for a 10-second test cycle. The force was measured by using the load cell, and the spinal deformation was measured by the linear variable differential transducer. The data were extracted and subjected to descriptive statistics and analysis of variance to determine the effect of independent variables on spinal stiffness.

RESULTS

The PA spinal stiffness at 3 spinal levels was significantly different (P < .0001). The spinal stiffness was significantly affected by the testing load, age, gender, and body weight of the subjects (P < .0001). The PA stiffness of the entire sample at 3 spinal levels ranged from 4.8-8.8 N/mm. The spinal stiffness values could be predicted as the function of testing load and body weight (P < .01).

CONCLUSIONS

Results of this experiment suggest that the standardized and repeatable methodology will result in reliable stiffness values. Because the spinal stiffness is an indicator of patient's symptoms and it is an important variable in selection of treatment regimen, it is important to be able to measure this variable with a standardized protocol. Values from asymptomatic subjects can be used to study and to compare the symptomatic patients.

Preliminary investigation of the mechanisms underlying the effects of manipulation: exploration of a multivariate model including spinal stiffness, multifidus recruitment, and clinical findings

STUDY DESIGN

Prospective case series.

OBJECTIVE

To examine spinal stiffness in patients with low back pain (LBP) receiving spinal manipulative therapy (SMT), evaluate associations between stiffness characteristics and clinical outcome, and explore a multivariate model of SMT mechanisms as related to effects on stiffness, lumbar multifidus (LM) recruitment, and status on a clinical prediction rule (CPR) for SMT outcomes.

SUMMARY OF BACKGROUND DATA

Mechanisms underlying the clinical effects of SMT are poorly understood. Many explanations have been proposed, but few studies have related potential mechanisms to clinical outcomes or considered multiple mechanisms concurrently.

METHODS

Patients with LBP were treated with two SMT sessions over 1 week. CPR status was assessed at baseline. Clinical outcome was based on the Oswestry disability index (ODI). Mechanized indentation measures of spinal stiffness and ultrasonic measures of LM recruitment were taken before and after each SMT, and after 1 week. Global and terminal stiffness were calculated. Multivariate regression was used to evaluate the relationship between stiffness variables and percentage ODI improvement. Zero-order correlations among stiffness variables, LM recruitment changes, CPR status, and clinical outcome were examined. A path analysis was used to evaluate a multivariate model of SMT effects.

RESULTS

Forty-eight patients (54% women) had complete stiffness data. Significant immediate decreases in global and terminal stiffness occurred post-SMT regardless of outcome. ODI improvement was related to greater immediate decrease in global stiffness (P = 0.025), and less initial terminal stiffness (P = 0.01). Zero-order correlations and path analysis supported a multivariate model suggesting that clinical outcome of SMT is mediated by improvements in LM recruitment and immediate decrease in global stiffness. Initial terminal stiffness and CPR status may relate to outcome though their relationship with LM recruitment.

CONCLUSION

The underlying mechanisms explaining the benefits of SMT appear to be multifactorial. Both spinal stiffness characteristics and LM recruitment changes appear to play a role.

Changes in bending stiffness and lumbar spine range of movement following lumbar mobilization and manipulation

OBJECTIVE

The purpose of this study was to investigate the effects of lumbar rotational manipulation and lumbar central posteroanterior mobilization on lumbar bending stiffness and flexion and extension range of motion (ROM).

METHODS

A same-subject, repeated-measures, crossover design was used using 32 asymptomatic subjects (16 female and 16 male; mean [SD] age, 25.5 [4.5] years; weight, 65.7 [11.8] kg; and height, 1.70 [0.08] m). Each subject received mobilization or manipulation on 2 different occasions. Bending stiffness was calculated using a 3-point bending model using an electromagnetic tracking device and a force platform; lumbar flexion and extension ROM was measured using an electromagnetic tracking device. All variables were measured pre- and postintervention. Their effect was compared using paired t tests.

RESULTS

Manipulation and mobilization did not significantly alter either bending stiffness or lumbar flexion and extension ROM (mobilization: P = .175, P = .613, and P = .535; manipulation: P = .973, P = .323, and P = .439). Bending stiffness changes were not correlated to changes in ROM (Pearson r for stiffness-flexion = -0.102, P = .586; Pearson r for stiffness-extension = 0.014, P = .941).

CONCLUSIONS

Manipulation and mobilization had no significant effect on bending stiffness or flexion and extension ROM for this group of subjects. Some individual variations in effect were observed.

Palpatory accuracy of lumbar spinous processes using multiple bony landmarks

OBJECTIVE

Accurate localization of vertebral segments is crucial for many treatment procedures. The objective of this study was to determine accuracy of identification of lumbar spinous process levels by palpation.

METHODS

Three examiners independently identified the spinous processes of L1-L4 on 60 prone volunteers using multiple bony landmarks including the sacral base, L5, Tuffier's line, T12, and the 12th ribs. The spinous processes were marked with radiopaque skin markers. Location of marker placement and presence of anatomical anomalies were determined by posteroanterior lumbar radiographs. Accuracy of marker placement and interobserver reliability were assessed using weighted κ values. Generalized linear mixed models and Cochran-Mantel-Haenszel tests assessed the relationship of accuracy to training level, presence of anatomical anomalies, and participant characteristics.

RESULTS

Examiners identified a spinous process in 91% of vertebral assessments. Correct identification of vertebral level occurred 69% of the time (κ = 0.81; 95% confidence interval, 0.79-0.83). Faculty examiners were significantly more accurate in identifying the correct vertebral level than the resident examiner (67%-78% vs 51%, P ≤ .03). The presence of 12th rib anomalies decreased accuracy for all examiners (P ≤ .05), reducing accuracy from 74% to 55%. Accuracy was higher in male participants than in female participants (P = .01). Obesity significantly decreased accuracy (P = .0003) at L3 (50% vs 73%) and L4 (44% vs 72%).

CONCLUSIONS

Identification of lumbar spinous processes using multiple landmarks was more accurate than previously reported values. However, accuracy was dependent on examiner experience, presence of anatomical anomalies, and participant characteristics.