Investigation des mécanismes qui sous-tendent les effets cliniques de la manipulation vertébrale dans la prise en charge des douleurs chroniques non spécifiques au rachis: rôle des réponses neuromécaniques et de la rigidité vertébrale

Les douleurs chroniques non spécifiques au rachis sont un fardeau socioéconomique important et entrainent de graves répercussions sur la qualité de vie des individus. L’utilisation de la manipulation vertébrale (MV) pour la prise en charge de cette condition est supportée par les données probantes actuelles. Cette thérapie génère des réponses neuromécaniques (réponses musculaires et déplacement vertébral) qui sont dépendantes des caractéristiques de celle-ci et qui pourraient influencer ses effets cliniques. De plus, un changement immédiat de la rigidité vertébrale pourrait aider à identifier les patients les plus enclins à s’améliorer à la suite de quelques séances de MVs. Malgré ces données, aucune étude n’a évalué les liens entre la dose de la MV, la rigidité vertébrale et l’évolution clinique de participants présentant une douleur au rachis. L’objectif principal de cette thèse est, à l’aide d’un appareil robotisé utilisant un moteur servo-linéaire, d’investiguer les mécanismes qui sous-tendent les effets cliniques de la MV dans la prise en charge des patients ayant une douleur chronique non-spécifique au rachis. Premièrement, la relation entre la dose de la MV (différentes forces maximales) et l’amplitude de la réponse musculaire lombaire a été comparée entre des participants sains et des participants présentant une lombalgie (étude 1). Considérant la nécessité d’identifier les processus transverses thoraciques lors de la 4e étude, une méthode de palpation de ceux-ci a ensuite été développée et validée (étude 2). La rigidité vertébrale a également été comparée entre des participants sains et des participants présentant une dorsalgie chronique et la fidélité de la mesure a été évaluée (étude 3). Enfin, les liens entre les caractéristiques de la MV (force maximale appliquée et taux d’application de la force), les réponses neuromécaniques, la rigidité vertébrale et l’évolution clinique de participants rapportant une dorsalgie chronique ont été évalués et les prédicteurs d’une amélioration clinique ont été identifiés (étude 4). Les résultats de la 1ère étude ont montré que l’amplitude de la réponse musculaire augmente avec l’augmentation de la force maximale appliquée chez les participants sains et ceux atteints de lombalgie chronique. Les résultats de la 3e étude suggèrent que la mesure de rigidité vertébrale est fidèle et que ce paramètre est diminué chez les participants présentant une dorsalgie. Enfin, les quatre groupes de participants de la 4e étude (trois doses de MV et un groupe sans MV) ont montré des changements cliniques et biomécaniques non significativement différents. Les participants ont montré, à la 4e séance, une diminution de l’intensité de la douleur, de l’incapacité, de la rigidité vertébrale et de la douleur lors de l’évaluation de celle-ci. Une amélioration clinique a été associée à une diminution de l’intensité de la douleur lors de l’évaluation de la rigidité vertébrale et de l’intensité de la douleur. En conclusion, les résultats de cette thèse suggèrent que, dans le cadre expérimental utilisé, les caractéristiques de la MV et, par conséquent, les réponses neuromécaniques lors de celle-ci influencent peu les effets cliniques de cette thérapie. D’autres études sont nécessaires afin d’évaluer les mécanismes qui sous tendent les effets cliniques de la MV.Chronic nonspecific back pain poses an important socioeconomic burden for society and has serious implications on patients’ quality of life. Spinal manipulation therapy (SMT) is now a therapeutic modality recommended by numerous practice guidelines. It is suggested that SMT clinical effects are, at least partly, associated to the neuromechanical responses (muscle response and vertebral displacement) characterizing this therapy. These responses have been shown to be dependent of the therapy characteristics. Moreover, an immediate decrease in spinal stiffness could help identify patients that are most likely to improve following few treatment sessions involving SMTs. Despite such evidence, associations between SMT characteristics and neuromechanical responses, spinal stiffness modulation, and the clinical evolution of patients with chronic nonspecific back pain remain unknown. The main objective of this thesis is to investigate, through an apparatus using a servocontrolled linear actuator motor, the mechanisms underlying the clinical effects of SMT in the management of chronic nonspecific back pain. Specifically, the relationship between SMT characteristics (peak force and rate of force application) and the amplitude of the lumbar paraspinal muscle response were compared between healthy participants and participants with chronic nonspecific low back pain (study 1). Considering that the fourth study would required the palpation of the thoracic transverse processes, a palpation method was developed and validated (study 2). Spinal stiffness was then compared between participants with and without chronic nonspecific thoracic pain and the measurement reliability was assessed (study 3). Finally, relationships between SMT characteristics, changes in spinal stiffness, and the clinical evolution of participants with chronic nonspecific thoracic pain, at one week following three treatment sessions, were evaluated and predictors of short-term improvement were also identified (study 4). First study results showed that the amplitude of the muscle response increases with the increase in the SMT peak force (and rate of force application) in participants with and without chronic low back pain. In the third study, spinal stiffness was shown to be reliable and lower spinal stiffness was observed in participants with chronic thoracic pain. The fourth study results revealed no significant differences in the clinical and biomechanical outcomes of the four groups of participants: three specific SMT doses and one control group not receiving SMT. Participants showed, at the fourth session, a decrease in pain intensity, disability, spinal stiffness and tenderness during spinal stiffness measurement. An improvement was associated with a decrease in tenderness and pain intensity. In conclusion, the thesis results suggest that, in this experimental setting, SMT characteristics and therefore, the neuromechanical responses to SMT, do not greatly influence this therapy clinical effects. Studies are still required to identify the mechanisms underlying the clinical effects of SM

Trunk muscle fatigue during a lateral isometric hold test: what are we evaluating?

Background Side bridge endurance protocols have been suggested to evaluate lateral trunk flexor and/or spine stabilizer muscles. To date, no study has investigated muscle recruitment and fatigability during these protocols. Therefore the purpose of our study was to quantify fatigue parameters in various trunk muscles during a modified side bridge endurance task (i.e. a lateral isometric hold test on a 45#194 #176 roman chair apparatus) and determine which primary trunk muscles get fatigued during this task. It was hypothesized that the ipsilateral external oblique and lumbar erector spinae muscles will exhibit the highest fatigue indices. Methods Twenty-two healthy subjects participated in this study. The experimental session included left and right lateral isometric hold tasks preceded and followed by 3 maximal voluntary contractions in the same position. Surface electromyography (EMG) recordings were obtained bilaterally from the external oblique, rectus abdominis, and L2 and L5 erector spinae. Statistical analysis were conducted to compare the right and left maximal voluntary contractions (MVC), surface EMG activities, right vs. left holding times and decay rate of the median frequency as the percent change from the initial value (NMF.sub.slope). Results No significant left and right lateral isometric hold tests differences were observed neither for holding times (97.2 [+ or -] 21.5 sec and 96.7 [+ or -] 24.9 sec respectively) nor for pre and post fatigue root mean square during MVCs. However, participants showed significant decreases of MVCs between pre and post fatigue measurements for both the left and right lateral isometric hold tests. Statistical analysis showed that a significantly NMF.sub.slope of the ipsilateral external oblique during both conditions, and a NMF.sub.slope of the contralateral L5 erector spinae during the left lateral isometric hold test were steeper than those of the other side's respective muscles. Although some participants presented positive NMF.sub.slope for some muscles, each muscle presented a mean negative NMF.sub.slope significantly different from 0. Conclusions Although the fatigue indices suggest that the ipsilateral external oblique and contralateral L5 erector spinae show signs of muscle fatigue, this task seems to recruit a large group of trunk muscles. Clinicians should not view this task as evaluating specifically lateral trunk flexors, but rather as providing an indication of the general endurance and stabilisation capacity of the trunk. Keywords: Side bridge test, Muscle fatigue, Trunk muscle, Functional testin

Assessing forces during spinal manipulation and mobilization: factors influencing the difference between forces at the patient-table and clinician-patient interfaces

Spinal manipulative therapy (SMT) and mobilization (MOB) effects are believed to be related to their force characteristics. Most previous studies have either measured the force at the patient-table interface or at the clinician-patient interface. The objectives of this study were to determine 1) the difference between the force measured at the patient-table interface and the force applied at the clinician-patient interface during thoracic SMT and MOB, and 2) the influence of the SMT/MOB characteristics, participants’ anthropometry and muscle activity (sEMG) on this difference

Minimal clinical data sets for spine-related musculoskeletal disorders in primary care and outpatient settings: a scoping review protocol

INTRODUCTION Lack of standardised clinical data collection may lead to reduced quality in musculoskeletal (MSK)-related clinical care and research. Little is known about the availability and characteristics of minimal clinical data sets for spine-related MSK disorders in primary care and outpatient settings and their utility for improving healthcare quality. Our objective is to undertake a scoping review aiming to identify and map current literature on minimal clinical data sets for measuring and monitoring health status in patients with spine-related MSK disorders in primary and outpatient healthcare settings. METHODS AND ANALYSIS The 2020 Joanna Briggs Institute methodology for scoping reviews will guide review conduct. The review will consider studies that describe and report on minimal clinical data sets for spine-related MSK disorders designed for primary care and outpatient clinical practice settings. Quantitative and qualitative study designs will be eligible, including consensus-based studies, interventional, observational, feasibility and linguistic validation studies. Studies published in English, German, French, Italian and Spanish will be included, with no limit on date of publication. MEDLINE, CINAHL, Cochrane Library, Index to Chiropractic Literature, MANTIS, ProQuest Dissertations & Theses Global and medRxiv preprint repository will be searched from database inception to 25 July 2021. Two reviewers will independently screen identified titles, abstracts and relevant full-text records, and then extract data using review-specific data extraction forms. Findings will be synthesised and presented as a descriptive summary using PRISMA ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews). ETHICS AND DISSEMINATION Ethics review and approval is not required for this scoping review. Our target audience for this review will be clinicians, researchers, patients and other relevant stakeholders involved in the measurement and health status monitoring of patients with spine-related MSK disorders. Results will be shared through peer-reviewed publication and presentations at relevant conferences. PROTOCOL REGISTRATION NUMBER: https://osf.io/fkw5b

The effect of spinal manipulation impulse duration on spine neuromechanical responses

INTRODUCTION: Spinal manipulation therapy (SMT) is characterized by specific kinetic and kinematic parameters that can be modulated. The purpose of this study is to investigate fundamental aspects of SMT dose-physiological response relation in humans by varying SMT impulse duration. METHODS: Twenty healthy adults were subjected to four different SMT force-time profiles delivered by a servo-controlled linear actuator motor and differing in their impulse duration. EMG responses of the left and right thoracic paraspinal muscles (T6 and T8 levels) and vertebral displacements of T7 and T8 were evaluated for all SMT phases. RESULTS: Significant differences in paraspinal EMG were observed during the “Thrust phase” and immediately after (“Post-SMT1”) (all T8 ps < 0.01 and T6 during the thrust ps < 0.05). Sagittal vertebral displacements were similar across all conditions (p > 0.05). CONCLUSION: Decreasing SMT impulse duration leads to a linear increase in EMG response of thoracic paraspinal during and following the SMT thrust

Spinal mobilization force-time characteristics:A scoping literature review

Abstract Background Spinal mobilization (SMob) is often included in the conservative management of spinal pain conditions as a recommended and effective treatment. While some studies quantify the biomechanical (kinetic) parameters of SMob, interpretation of findings is difficult due to poor reporting of methodological details. The aim of this study was to synthesise the literature describing force-time characteristics of manually applied SMob. Methods This study is reported in accordance with the Preferred Reporting Items for Scoping Reviews (PRISMA-ScR) statement. Databases were searched from inception to October 2022: MEDLINE (Ovid), Embase, CINAHL, ICL, PEDro and Cochrane Library. Data were extracted and reported descriptively for the following domains: general study characteristics, number of and characteristics of individuals who delivered/received SMob, region treated, equipment used and force-time characteristics of SMob. Results There were 7,607 records identified and of these, 36 (0.5%) were included in the analysis. SMob was delivered to the cervical spine in 13 (36.1%), the thoracic spine in 3 (8.3%) and the lumbopelvic spine in 18 (50.0%) studies. In 2 (5.6%) studies, spinal region was not specified. For SMob applied to all spinal regions, force-time characteristics were: peak force (0-128N); duration (10-120s); frequency (0.1–4.5Hz); and force amplitude (1-102N). Conclusions This study reports considerable variability of the force-time characteristics of SMob. In studies reporting force-time characteristics, SMob was most frequently delivered to the lumbar and cervical spine of humans and most commonly peak force was reported. Future studies should focus on the detailed reporting of force-time characteristics to facilitate the investigation of clinical dose-response effects

Neuromechanical response to spinal manipulation therapy: effects of a constant rate of force application

Background Neuromechanical responses to spinal manipulation therapy (SMT) have been shown to be modulated through the variation of SMT biomechanical parameters: peak force, time to peak force, and preload force. Although rate of force application was modulated by the variation of these parameters, the assumption that neuromuscular responses are modulated by the rate of force application remains to be confirmed. Therefore, the purpose of the present study was to evaluate the effect of a constant rate of force application in neuromechanical responses to SMT in healthy adults. Methods Four SMT force-time profiles presenting different time to peak force and peak force, but with a constant rate of force application were applied on 25 healthy participants' T7 transverse processes. Muscular responses were recorded through surface electromyography electrodes (T6 and T8 levels), while vertebral displacements were assessed through pasted kinematic markers on T6 to T8 spinous processes. Effects of SMT force-time profiles on neuromechanical responses were assessed using repeated-measures ANOVAs. Results There was no main effect of SMT force-time profile modulation on muscular responses (ps > .05) except for the left T8 (F (3, 72) = 3.23, p = .03) and left T6 (F (3, 72) = 2.94, p = .04). Muscular responses were significantly lower for the lowest peak force condition than the highest (for T8) or second highest (for T6). Analysis showed that increasing the SMT peak force (and concomitantly time to peak force) led to a significant vertebral displacement increase for the contacted vertebra (F T7 (1, 17) = 354.80, p < .001) and both adjacent vertebras (F T6 (1, 12) = 104.71, p < .001 and F T8 (1, 19) = 468.68, p < .001). Conclusion This study showed that peak force modulation using constant rate of force application leads to similar neuromuscular responses. Coupled with previous investigations of SMT peak force and duration effects, the results suggest that neuromuscular responses to SMT are mostly influenced by the rate of force application, while peak force modulation yields changes in the vertebral displacement. Rate of force application should therefore be defined in future studies. Clinical implications of various SMT dosages in patients with spine related pain should also be investigated

Chronic low back pain clinical outcomes present higher associations with the STarT Back Screening Tool than with physiologic measures: a 12-month cohort study

Stratification strategies based on identifying patient's prognosis in order to guide patient care constitute one of the most prominent and recent approach in low back pain research. The STarT Back Screening Tool (SBST) although promising, has not been studied in patients with chronic low back pain (cLBP). Considering how challenging it is to translate research into practice, the value of integrating a new tool should be thoroughly assessed. The purpose was therefore to assess associations between the short- and long-terms clinical status and two types of variables, physiologic measures and the SBST, in participants with cLBP. The ability of both types of variables to discriminate between participants with and without higher levels of disability, pain, fear of movement and patient's global impression of change was also investigated