Efficacy of a Psychologically-Informed Physiotherapy Intervention in Patients with Chronic Low Back Pain at High Risk of Poor Prognosis: A Pilot and Feasibility Randomized Controlled Trial.

Purpose: To determine the feasibility of a randomized controlled trial (RCT) testing the efficacy of psychologically-informed physiotherapy (PIPT), which includes usual physiotherapy (UP) interventions, compared with UP, and to explore the preliminary effectiveness of the interventions. Method: People with chronic low back pain at high risk of poor prognosis (using the STarT Back screening tool) were recruited and allocated to PIPT or UP. Effectiveness of recruitment strategies, adherence to intervention, risk of contamination, and specific challenges were assessed. Functional capacity, pain, quality of life, kinesiophobia, catastrophization, central sensitization, and self-efficacy were measured at baseline, 6-, 12- and 24-week follow-ups. Results: Forty participants were recruited mainly by diffusing through Laval University's email list, and 10 physiotherapists treated the participants recruited. The retention rate of participants at 24 weeks was 72.5%. Adherence to treatment by participants and physiotherapists was very good. The risk of contamination was low, and the specific challenges identified were modifiable. Significant improvement over time in all clinical variables of interest, except self-efficacy, was observed with no difference between groups. Conclusions: As most success criteria were met, conducting an RCT evaluating PIPT and PU is feasible with modifications. PIPT and UP appear to be similarly effective.

Objectif: déterminer la faisabilité d'une étude randomisée et contrôlée (ÉRC) évaluant l'efficacité de la physiothérapie fondée sur la psychologie (PTFP), qui inclut les interventions de physiothérapie conventionelle (PC), par rapport à la PC, et explorer l'efficacité préliminaire des interventions. Méthodologie: les chercheurs ont recruté des personnes qui souffrent de douleurs lombaires chroniques, ayant une probabilité élevée de mauvais pronostic (au moyen de l'outil de dépistage STarT Back) et les ont réparties entre la PTFP et la PC. Ils ont évalué l'efficacité des stratégies de recrutement, l'adhésion à l'intervention, le risque de contamination et les difficultés particulières. Ils ont également mesuré la capacité fonctionnelle, la douleur, la qualité de vie, la kinésiophobie, la catastrophisation, la sensibilisation centrale et l'autoefficacité en début d'étude ainsi que lors des suivis à six, 12 et 24 semaines. Résultats: les chercheurs ont recruté 40 participants, principalement en diffusant le projet par courriel à la communauté de l'Université Laval, et dix physiothérapeutes les ont traités. Le taux de rétention des participants était de 72,5 % à 24 semaines. Les participants et les physiothérapeutes ont démontré une très bonne adhésion au traitement. Le risque de contamination était faible, et les difficultés particulières constatées pouvaient être modifiées. Les chercheurs ont observé une amélioration considérable au fil du temps pour toutes les variables cliniques d'intérêt, sauf l'autoefficacité, sans différence entre les groupes. Conclusions: puisque la plupart des critères de succès étaient respectés, il est faisable de réaliser une ÉRC pour évaluer la PTFP et la PU, sous réserve de modifications. La PTFP et la PC semblent avoir une efficacité similaire.

Motor control of the spine in pregnancy-related lumbopelvic pain: A systematic review.

BACKGROUND: Some studies observed differences in motor control of the spine between women with pregnancy-related lumbopelvic pain and matched controls. Understanding alterations in spine motor control may help optimizing treatment in this population. The objective is to determine if there are differences in motor control of the spine in pregnant and post-partum women with and without pregnancy-related lumbopelvic pain. METHODS: Five databases were searched: MEDLINE, Embase, CINAHL, Web of Science and Evidence-Based Medicine Reviews (last search: February 4th 2021). Observational studies that compared motor control of the lumbopelvic spine (in terms of muscle activation [e.g. using EMG or ultrasound imaging] or kinematics) between women with pregnancy-related lumbopelvic pain and matched controls were included. Risk of bias was assessed with a modified version of STROBE statement for cross-sectional studies. No meta-analysis was performed. FINDING: Fifteen studies were included. Compared to matched controls, pregnant women with pregnancy-related lumbopelvic pain showed differences in lumbar spine kinematic during walking and lifting, although not consistent between studies. The only consistent results were higher transversus abdominis muscle activation during leg movements in post-partum pregnancy-related lumbopelvic pain. Differences in pelvic floor muscle function was inconsistent. INTERPRETATION: This systematic review identified multiple differences in motor control in pregnancy-related lumbopelvic pain population, predominantly in dynamic tasks. However, consistent differences in lumbopelvic spine motor control were rare. More studies are necessary to determine if motor control is different in pregnancy-related lumbopelvic pain to better understand alteration in motor control and to optimize the efficacy of rehabilitation treatments.

The influence of experimental low back pain on neural networks involved in the control of lumbar erector spinae muscles.

Low back pain (LBP) often modifies spine motor control, but the neural origin of these motor control changes remains largely unexplored. This study aimed to determine the impact of experimental low back pain on the excitability of cortical, subcortical, and spinal networks involved in the control of back muscles. Thirty healthy subjects were recruited and allocated to pain (capsaicin and heat) or control (heat) groups. Corticospinal excitability (motor-evoked potential; MEP) and intracortical networks were assessed by single- and paired-pulse transcranial magnetic stimulation, respectively. Electrical vestibular stimulation was applied to assess vestibulospinal excitability (vestibular MEP; VMEP) and the stretch reflex for excitability of the spinal or supraspinal loop (R1 and R2, respectively). Evoked back motor responses were measured before, during, and after pain induction. Nonparametric rank-based ANOVA determined if pain modulated motor neural networks. A decrease of R1 amplitude was present after the pain disappearance (P = 0.01) whereas an increase was observed in the control group (P = 0.03) compared with the R1 amplitude measured at prepain and preheat period, respectively (group × time interaction, P < 0.001). No difference in MEP and VMEP amplitude was present during and after pain (P > 0.05). During experimental LBP, no change in cortical, subcortical, or spinal networks was observed. After pain disappearance, the reduction of the R1 amplitude without modification of MEP and VMEP amplitude suggests a reduction in spinal excitability potentially combined with an increase in descending drives. The absence of effect during pain needs to be further explored.NEW & NOTEWORTHY In the presence of experimental low back pain, spinal, subcortical, and cortical motor networks involved in the control of back muscles were not modified. However, once the pain disappeared, a reduction in motoneuronal excitability was observed without change in corticospinal and vestibulospinal excitability, suggesting a reduction in descending drive. Experimental low back pain may elicit long-term plasticity even after pain extinction.

Influence of different transcranial magnetic stimulation current directions on the corticomotor control of lumbar erector spinae muscles during a static task.

Different directions of transcranial magnetic stimulation (TMS) can activate different neuronal circuits. Whereas posteroanterior current (PA-TMS) depolarizes mainly interneurons in primary motor cortex (M1), an anteroposterior current (AP-TMS) has been suggested to activate different M1 circuits and perhaps axons from the premotor regions. Although M1 is also involved in the control of axial muscles, no study has explored whether different current directions activate different M1 circuits that may have distinct functional roles. The aim of the study was to compare the effect of different current directions (PA- and AP-TMS) on the corticomotor control and spatial cortical organization of the lumbar erector spinae muscle (LES). Thirty-four healthy participants were recruited for two independent experiments, and LES motor-evoked potentials (MEPs) were recorded. In experiment 1 (n = 17), active motor threshold (AMT), MEP latencies, recruitment curve (90% to 160% AMT), and excitatory and inhibitory intracortical mechanisms by paired-pulse TMS (80% followed by 120% AMT stimuli at 2-, 3-, 10-, and 15-ms interstimulus intervals) were tested with a double-cone (n = 12) and a figure-of-eight (n = 5) coil. In experiment 2 (n = 17), LES cortical representations were tested with PA- and AP-TMS. AMT was higher for AP- compared with PA-TMS (P = 0.002). Longer latencies with AP-TMS were present compared with PA-TMS (P = 0.017). AP-TMS produced more inhibition compared with PA-TMS at 2 ms and 3 ms (P = 0.010), but no difference was observed for longer intervals. No difference was found for recruitment curve and mapping. These findings suggest that PA- and AP-TMS may activate different cortical circuits controlling low back muscles, as proposed for hand muscles.NEW & NOTEWORTHY For the first time, anteroposterior and posteroanterior induced electric currents in the brain were compared when targeting back muscle representation with transcranial magnetic stimulation. The use of the anteroposterior current resulted in later response latency, larger inhibition probed by paired-pulse stimulation, and higher motor threshold. These important differences between current directions suggest that each of the current directions may recruit specific cortical circuits involved in the control of back muscles, similar to that for hand muscles.

Motor Responses of Lumbar Erector Spinae Induced by Electrical Vestibular Stimulation in Seated Participants.

Introduction: The study of motor responses induced by electrical vestibular stimulation (EVS) may help clarify the role of the vestibular system in postural control. Although back muscles have an important role in postural control, their EVS-induced motor responses were rarely studied. Moreover, the effects of EVS parameters, head position, and vision on EVS-induced back muscles responses remain little explored. Objectives: To explore the effects of EVS parameters, head position, and vision on lumbar erector spinae muscles EVS-induced responses. Design: Exploratory, cross-sectional study. Materials and Methods: Ten healthy participants were recruited. Three head positions (right, left and no head rotation), 4 intensities (2, 3, 4, 5 mA), and 4 EVS durations (5, 20, 100, 200 ms) were tested in sitting position with eyes open or closed. EVS usually induced a body sway toward the anode (placed on the right mastoid). EMG activity of the right lumbar erector spinae was recorded. Variables of interest were amplitude, occurrence, and latency of the EVS-induced modulation of the EMG activity. Results: The short-latency response was inhibitory and the medium-latency response was excitatory. Increased EVS current intensity augmented the occurrence and the amplitude of the short- and medium-latency responses (more inhibition and more excitation, respectively). EVS duration influenced the medium-latency response differently depending on the position of the head. Right head rotation produced larger responses amplitude and occurrence than left head rotation. Opposite head rotation (left vs. right) did not induce a reversal of the short- and medium-latency responses (i.e., the inhibition did not become an excitation), as typically reported in lower legs muscles. The eyes open condition did not modulate muscle responses. Conclusion: Modulation of EVS parameters (current intensity and duration of EVS) affects the amplitude and occurrence of the lumbar erector spinae responses. In contrast, vision did not influence the responses, suggesting its minimal contribution to vestibulomotor control in sitting. The lack of response reversal in sagittal plane may reflect the biomechanical role of lumbar erector spinae to fine-tune the lumbar lordosis during the induced body sway. This hypothesis remains to be further tested.