Criterion validity of manual assessment of spinal stiffness

Variability of spinal stiffness and its relation to daily activities: A prospective cohort study using a mechanical assisted indentation technique

BACKGROUND

Spinal stiffness is a potentially important cause of spinal pain but we have limited knowledge of its variability in relation to daily activities. This study investigated the association between variability of spinal stiffness and body anthropometry, age, and different daily activities in a cohort of healthy participants.

METHODS

A cross-sectional study of a cohort of 25 healthy participants (median age 24 years; 52% male) was employed to collect stiffness measurements obtained through surface indentation of the lumbar and thoracic spine three times over the course of a single day. Daily activities (sitting, standing, and movement) were assessed using accelerometer data. Linear mixed models analyzed the associations between stiffness variability and body anthropometry, age, and activities.

FINDINGS

We observed significant variability in spinal stiffness among individuals, with greater variability in the lumbar region compared to the thoracic region. Both sedentary and standing activities influenced stiffness variability at a statistically significant level. However, body anthropometry and age was not associated with stiffness variability.

INTERPRETATION

Our study demonstrates that daily activities (i.e., sedentary and standing) contribute to the variability of spinal stiffness during the day. Age and sex did not significantly impact stiffness variability. Further investigations are warranted to explore the clinical implications of stiffness changes.

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.

Effects of the Addition of Hands-on Procedures to McKenzie Exercises on Pain, Functional Disability and Back Mobility in Patients with Low Back Pain: A Randomised Clinical Trial

Background

Low back pain (LBP) is a common musculoskeletal disorder that affects people of all ages. This study investigates the effects of the addition of hands-on procedures to McKenzie exercises on patients with LBP and derangement syndrome.

Methods

Forty-eight female patients were randomly assigned to either the experimental group or control group. All the patients in both groups underwent McKenzie exercises, transcutaneous electrical nerve stimulation (TENS) and education for 35 min/session-45 min/ session, with three sessions/week for 2 weeks. Hands-on procedures were added to the McKenzie extension exercises only for the patients in the experimental group. A visual analogue scale (VAS), the Oswestry disability index (ODI), back range of motion (BROM) and body diagrams were used to measure pain, functional disability, BROM and the centralisation of symptoms, respectively.

Results

The mean values of VAS, ODI and BROM significantly improved after the interventions in both groups (P < 0.05), whereas the results of repeated measures ANOVA and Mann-Whitney U tests showed statistically non-significant differences between the two groups (P > 0.05).

Conclusion

The addition of hands-on procedures to McKenzie exercises, TENS and education significantly alleviated back pain and functional disability and improved the back mobility and centralisation of symptoms in patients with LBP and derangement syndrome; however, these measures did not result in any significant additional benefits for such patients.

Diagnosis Value of Patient Evaluation Components Applicable in Primary Care Settings for the Diagnosis of Low Back Pain: A Scoping Review of Systematic Reviews

Low back pain ranks as the leading cause of years lived with disability worldwide. Although best practice guidelines share a consistent diagnostic approach for the evaluation of patients with low back pain, confusion remains as to what extent patient history and physical examination findings can inform management strategies. The aim of this study was to summarize evidence investigating the diagnostic value of patient evaluation components applicable in primary care settings for the diagnosis of low back pain. To this end, peer-reviewed systematic reviews were searched in MEDLINE, CINAHL, PsycINFO and Cochrane databases from 1 January 2000 to 10 April 2023. Paired reviewers independently reviewed all citations and articles using a two-phase screening process and independently extracted the data. Of the 2077 articles identified, 27 met the inclusion criteria, focusing on the diagnosis of lumbar spinal stenosis, radicular syndrome, non- specific low back pain and specific low back pain. Most patient evaluation components lack diagnostic accuracy for the diagnosis of low back pain when considered in isolation. Further research is needed to develop evidence-based and standardized evaluation procedures, especially for primary care settings where evidence is still scarce.

Reliability and validity of manual palpation for the assessment of patients with low back pain: a systematic and critical review

BACKGROUND

Static or motion manual palpation of the low back is commonly used to assess pain location and reproduction in low back pain (LBP) patients. The purpose of this study is to review the reliability and validity of manual palpation used for the assessment of LBP in adults.

METHOD

We systematically searched five databases from 2000 to 2019. We critically appraised internal validity of studies using QAREL and QUADAS-2 instruments. We stratified results using best-evidence synthesis. Validity studies were classified according to Sackett and Haynes.

RESULTS

We identified 2023 eligible articles, of which 14 were low risk of bias. Evidence suggests that reliability of soft tissue structures palpation is inconsistent, and reliability of bony structures and joint mobility palpation is poor. We found preliminary evidence that gluteal muscle palpation for tenderness may be valid in differentiating LBP patients with and without radiculopathy.

CONCLUSION

Reliability of manual palpation tests in the assessment of LBP patients varies greatly. This is problematic because these tests are commonly used by manual therapists and clinicians. Little is known about the validity of these tests; therefore, their clinical utility is uncertain. High quality validity studies are needed to inform the clinical use of manual palpation tests.

Distinguishing chronic low back pain in young adults with mild to moderate pain and disability using trunk compliance

Chronic low back pain (cLBP) rates among younger individuals are rising. Although pain and disability are often less severe, underlying changes in trunk behavior may be responsible for recurrence. We examine the biomarker capacity of a simple Trunk Compliance Index (TCI) to distinguish individuals with and without cLBP. A random subset (n = 49) of the RELIEF RCT were matched to healthy controls for sex, age, height and weight. We measured TCI (as displacement/ weight-normalized perturbation force) using anthropometrically-matched, suddenly-applied pulling perturbations to the trunk segment, randomized across three planes of motion (antero-posterior, medio-lateral, and rotational). Mean differences between cLBP, sex and perturbation direction were assessed with repeated-measures analysis of variance. Discriminatory accuracy of TCI was assessed using Receiver Operator Characteristic (ROC) analysis. Baseline characteristics between groups were equivalent (x̅ [range]): sex (57% female / group), age (23.0 [18-45], 22.8 [18-45]), height, cm (173.0 [156.5-205], 171.3 [121.2-197], weight, kg (71.8 [44.5-116.6], 71.7 [46.8-117.5]) with cLBP associated with significantly lower TCI for 5 of 6 directions (range mean difference, - 5.35: - 1.49, range 95% CI [- 6.46: - 2.18 to - 4.35: - 0.30]. Classification via ROC showed that composite TCI had high discriminatory potential (area under curve [95% CI], 0.90 [0.84-0.96]), driven by TCI from antero-posterior perturbations (area under curve [95% CI], 0.99 [0.97-1.00]). Consistent reductions in TCI suggests global changes in trunk mechanics that may go undetected in classic clinical examination. Evaluation of TCI in younger adults with mild pain and disability may serve as a biomarker for chronicity, leading to improved preventative measures in cLBP.Trial Registration and Funding RELIEF is registered with clinicaltrials.gov (NCT01854892) and funded by the NIH National Center for Complementary & Integrative Health (R01AT006978).

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.

Biomechanical characteristics of lumbar manipulation performed by expert, resident, and student physical therapists

BACKGROUND

Lumbar manipulation is a commonly used treatment for low back pain, but little research evidence exists regarding practitioner biomechanics during manipulation. Most existing evidence describes rate of force production through the hands into instrumented manikins and it is unclear how the practitioner moves their body and legs to generate this force.

OBJECTIVES

To identify and characterize important kinetic and kinematic factors in practitioners of varying experience performing lumbar manipulation in order to identify which factors distinguish experts from less experienced practitioners.

STUDY DESIGN

This was a cohort observational laboratory study.

METHODS

43 male physical therapists (PT) and PT students (4 experts, 11 residents, 13 third year, and 15 first year students) performed 4 manipulations each on asymptomatic patient models. Angular and linear kinematics of the pelvis were measured using motion capture, and ground reaction forces were measured with force plates under the practitioner's feet.

RESULTS

Peak pelvic angular velocity was greater and in the opposite direction in experts compared to other groups in the frontal plane (p = 0.020) and transverse plane (p = 0.000). Experts had greater downward pelvic linear velocity than third year students and first year students (p = 0.000). Experts also demonstrated faster rate of vertical ground reaction force unloading during the manipulation (p = 0.002).

CONCLUSIONS

Expert performance of manipulation was characterized by increased speed of linear and angular pelvic motion, and increased modulation of vertical ground reaction force. These results help to inform educators and practitioners that teach and use this complex manual skill.

Changes in spinal stiffness with chronic thoracic pain: Correlation with pain and muscle activity

Objective

The objective was to compare thoracic spinal stiffness between healthy participants and participants with chronic thoracic pain and to explore the associations between spinal stiffness, pain and muscle activity. The reliability of spinal stiffness was also evaluated.

Material and methods

Spinal stiffness was assessed from T5 to T8 using a mechanical device in 25 healthy participants and 50 participants with chronic thoracic pain (symptoms had to be reported within the evaluated region of the back). The spinal levels for which spinal stiffness was measured were standardized (i.e. T5 to T8 for all participants) to minimize between-individual variations due to the evaluation of different spinal levels. The device load and displacement data were used to calculate the global and terminal spinal stiffness coefficients at each spinal level. Immediately after each assessment, participants were asked to rate their pain intensity during the trial, while thoracic muscle activity was recorded during the load application using surface electromyography electrodes (sEMG). Within- and between-day reliability were evaluated using intraclass correlation coefficients (ICC), while the effects of chronic thoracic pain and spinal levels on spinal stiffness and sEMG activity were assessed using mixed model ANOVAs. Correlations between pain intensity, muscle activity and spinal stiffness were also computed.

Results

ICC values for within- and between-day reliability of spinal stiffness ranged from 0.67 to 0.91 and from 0.60 to 0.94 (except at T5), respectively. A significant decrease in the global (F_1,73 = 4.04, p = 0.048) and terminal (F_1,73 = 4.93, p = 0.03) spinal stiffness was observed in participants with thoracic pain. sEMG activity was not significantly different between groups and between spinal levels. Pain intensity was only significantly and "moderately" correlated to spinal stiffness coefficients at one spinal level (-0.29≤r≤-0.51), while sEMG activity and spinal stiffness were not significantly correlated.

Conclusion

The results suggest that spinal stiffness can be reliably assessed using a mechanical device and that this parameter is decreased in participants with chronic thoracic pain. Studies are required to determine the value of instrumented spinal stiffness assessment in the evaluation and management of patients with chronic spine-related pain.

Unraveling the Mechanisms of Manual Therapy: Modeling an Approach

Synopsis Manual therapy interventions are popular among individual health care providers and their patients; however, systematic reviews do not strongly support their effectiveness. Small treatment effect sizes of manual therapy interventions may result from a "one-size-fits-all" approach to treatment. Mechanistic-based treatment approaches to manual therapy offer an intriguing alternative for identifying patients likely to respond to manual therapy. However, the current lack of knowledge of the mechanisms through which manual therapy interventions inhibit pain limits such an approach. The nature of manual therapy interventions further confounds such an approach, as the related mechanisms are likely a complex interaction of factors related to the patient, the provider, and the environment in which the intervention occurs. Therefore, a model to guide both study design and the interpretation of findings is necessary. We have previously proposed a model suggesting that the mechanical force from a manual therapy intervention results in systemic neurophysiological responses leading to pain inhibition. In this clinical commentary, we provide a narrative appraisal of the model and recommendations to advance the study of manual therapy mechanisms. J Orthop Sports Phys Ther 2018;48(1):8-18. doi:10.2519/jospt.2018.7476.

Manipulation Peak Forces Across Spinal Regions for Children Using Mannequin Simulators

OBJECTIVE

The purpose of this work was to create an exploratory database of manipulation treatment force variability as a function of the intent of an experienced clinician sub-specializing in the care of children to match treatment to childhood category. Data of this type are necessary for realistic planning of dose-response and safety studies on therapeutic benefit.

METHODS

The project evaluated the transmitted peak forces of procedures applied to mannequins of different stature for younger and older children. Common procedures for the cervical, thoracic, and lumbar spine and sacroiliac joint were administered to estimate variability by a single experienced practitioner and educator in pediatric manipulation attempting to modulate for childhood category. Results described for peak components in the cardinal axes and for peak total forces were cataloged and compared with consensus estimates of force from the literature.

RESULTS

Mean force values for both components and total force peaks monotonically increased with childhood category analogous to consensus expectations. However, a mismatch was observed between peak values measured and consensus predictions that ranged by a factor of 2 to 3.5, particularly in the upper categories. Quantitative data permit a first estimate of effect size for future clinical studies.

CONCLUSIONS

The findings of this study indicate that recalibration of spinal manipulation performance of experienced clinicians toward arbitrary target values similar to consensus estimates is feasible. What is unclear from the literature or these results is the identity of legitimate target values that are both safe and clinically effective based on childhood categories in actual practice.

Interrater Reliability of Motion Palpation in the Thoracic Spine

Introduction. Manual therapists commonly use assessments of intervertebral motion to determine the need for spinal manipulation, but the reliability of these procedures demonstrates conflicting results. The objectives of this study were to investigate the interrater reliability of thoracic spine motion palpation for perceived joint restriction and pain. Methods. Twenty-five participants between the ages of 18 and 70, with or without mid-back pain, were enrolled. Two raters motion palpated marked T5–T12 levels using two methods (standardised and pragmatic) and noted any restricted or painful segments. We calculated agreement between two raters by generating raw agreement percentages and Kappa coefficients with 95% confidence intervals. Results. There was poor to low level of agreement between the raters for both joint stiffness and pain localization using both pragmatic and standardized approaches. The results did not improve significantly when we conducted a post hoc analysis where three spinal levels were collapsed as one and right and left sides were also combined. Conclusions. The results for interrater reliability were poor for motion restriction and pain. These findings may have unfavourable implications for all manual therapists who use motion palpation to select patients appropriate for spinal manipulation.

Comparison of cervical spine stiffness in individuals with chronic nonspecific neck pain and asymptomatic individuals

STUDY DESIGN

Clinical measurement, cross-sectional.

OBJECTIVE

To determine if spinal joint stiffness is different in individuals with nonspecific neck pain, and whether stiffness magnitude is associated with pain intensity and disability.

BACKGROUND

Manual therapists commonly evaluate spinal joint stiffness in patients presenting with nonspecific neck pain. However, a relationship between stiffness and neck pain has not yet been demonstrated.

METHODS

Spinal stiffness at C7 was objectively measured in participants with chronic nonspecific neck pain whose symptomatic spinal level was identified as C7 (n = 12) and in age- and sex-matched asymptomatic controls (n = 12). Stiffness (slope of the linear region of the force-displacement curve) was quantified using a device that applied 5 standardized mechanical force cycles to the C7 spinous process, while concurrently measuring displacement and resistance to movement. Stiffness was compared between groups using an independent t test. Spearman rho and Pearson r were used to determine the extent to which stiffness magnitude was associated with pain intensity (visual analog scale) and level of disability (Neck Disability Index), respectively, in the group with neck pain.

RESULTS

Participants with nonspecific neck pain had greater spinal joint stiffness at C7 compared with asymptomatic individuals (mean difference, 1.78 N/mm; 95% confidence interval: 0.28, 3.27; P = .022). However, stiffness magnitude in the group with neck pain was not associated (P>.05) with pain intensity or level of disability.

CONCLUSION

These preliminary results suggest that cervical spine stiffness may be greater in the presence of nonspecific neck pain. However, judgments regarding pain intensity and level of disability should not be inferred from examinations of spinal joint stiffness.