The goal of this clinical trial is to test the effects of spinal manipulative therapy in individuals with chronic primary low back pain and determine the neurophysiological mechanisms underlying pain relief. The main questions it aims to answer are: • Is pain relief produced by spinal manipulative therapy in patients with chronic primary low back pain caused by a reduction of C-fiber-related nociceptive processing? • Are these effects greater when spinal manipulative therapy is applied to the whole spine where it is clinically indicated compared with lumbar spine only? • Are these effects greater after 36 treatments over 3 months compared with 12 treatments over 1 month. Participants will receive spinal manipulative therapy (all clinically indicated spine segments or back only) or a control intervention. A group of healthy volunteers will be recruited to assess secondary outcome measures over the same time period, as reference data for comparisons. Researchers will compare the two groups receiving spinal manipulative therapy to the group receiving the control intervention to see if clinical pain relief and the reduction of temporal summation of second pain (produced experimentally) is significantly greater with spinal manipulative therapy.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
112
Spinal manipulative therapy involves the application of spinal manipulation over several sessions. Spinal manipulation is defined as a high-velocity, low-amplitude thrust performed by a clinician to move a segment of the spine in a specific direction. This type of intervention often generates cavitation sounds (audible pops).
Sham spinal manipulative therapy (sham SMT), was designed to be structurally equivalent to SMT, i.e., to attend to the same body regions with the same amount of contact as well as to have the same number, frequency and length of sessions. SMT and sham SMT will be provided by the same treatment provider and will appear to be similarly tailored to the participants' condition. Sham SMT does not share the component of interest of SMT, i.e., the activation of deep high-threshold mechanoreceptors via high-velocity, low-amplitude thrusts applied to the spine. Yet, it shares all the other components not of interest in this study that may contribute to the placebo response, such as therapeutic alliance, contextual factors, physical touch, and expectations. Furthermore, deception will be used to balance expectations and enhance blinding.
Spinal manipulative therapy involves the application of spinal manipulation over several sessions. Spinal manipulation is defined as a high-velocity, low-amplitude thrust performed by a clinician to move a segment of the spine in a specific direction. This type of intervention often generates cavitation sounds (audible pops).
Université du Québec à Trois-Rivières
Trois-Rivières, Quebec, Canada
RECRUITINGlow back pain intensity
In accordance with recommendations for chronic pain trials, participants will be instructed to rate the intensity of their LBP using a numerical rating scale (NRS) ranging from 0 (no pain) to 10 (worst pain imaginable). As in the brief pain inventory (BPI), they will be instructed to rate their pain: 1) right now; 2) on average over the last 7 days; 3) at its worst over the last 7 days; 4) at its best over the last 7 days.
Time frame: baseline, 1- , 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11-, 12-, 26-, 39-, 52- and 64-weeks post-randomization.
temporal summation of second pain
Participants will receive a total of 160 painful laser stimuli, 80 single-pulse stimuli and 80 pulse trains (3 pulses delivered at 0.67 Hz). After each stimulus, participants will be prompted to rate second pain with the display of a numerical pain rating scale. The pain ratings of single pulses will be subtracted from the pain ratings of pulse trains to estimate the intensity of the temporal summation of second pain.
Time frame: baseline, 4- and 12-weeks post-randomization.
low back pain frequency and duration
A modified version of the pain frequency-severity-duration scale will be used. Participants will be instructed to answer these 3 questions: * Is the pain recurrent (it comes in episodes) or continuous (it is always present)? * How many days in the past week have you had low back pain? (0, 1, 2, 3, 4, 5, 6, 7 days; a higher score means a worse outcome) * On average, how many hours per day does the pain last? (0; 1-4; 5-8; 9-12; 13-16; 17-20; 21-24 hours; a higher score means a worse outcome)
Time frame: baseline, 1- , 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11-, 12-, 26-, 39-, 52- and 64-weeks post-randomization.
Pressure pain thresholds (PPTs)
PPT will be measured using a handheld digital algometer (Wagner Pain TestTM FPX, Greenwich, Connecticut, USA) and a standardized protocol. The algometer will be applied perpendicularly to the skin of the first test location and the pressure increased at approximately 50 kPa/s until pain is reported by the participant. This procedure will be repeated three times at the same test location. The PPT will be the average of the values obtained during these 3 trials. The same procedures will be repeated at the two other test locations. PPT will be tested on three different body locations: 1) Over the spinous process of the most painful vertebra between L1 and S1; 2) On the right lower limb in the dermatome corresponding to the level of the most painful vertebra; 3) in the center of the right thenar eminence.
Time frame: baseline, 4- and 12-weeks post-randomization.
C-fiber-related brain responses
Electroencephalography (EEG) will be recorded using a 64-channel BrainVision system with active Ag-AgCl electrodes mounted on an actiCAP, according to the International 10-20 system (Brain Products, Gilching, Germany). Electrodes will be nose-referenced, and the ground will be set at FPz. Signals will be sampled at 500 Hz. Eye movements and blinks will be recorded using electrooculography (EOG). Electrode impedance will be kept below 20 kΩ. Closed eyes resting state EEG will be recorded for 5 min prior to laser stimuli for exploratory EEG analyses. EEG activity will be recorded continuously. The outcome of interest from laser-evoked-brain activity is the response evoked by C-fiber activation. Laser-evoked potentials (LEP) and event-related spectral perturbations (ERSP) will be analyzed using validated methods.
Time frame: baseline, 4- and 12-weeks post-randomization.
Oswestry Disability Index (ODI)
Self-reported low back pain related disability will be evaluated using the French-Canadian version of the ODI (0-100%; a higher score means a worse outcome).
Time frame: baseline, 4-, 12-, 26-, 39-, 52- and 64-weeks post-randomization.
Back performance scale (BPS)
The BPS will be used as a performance based outcome of physical function. It includes five daily activities such as putting socks on or picking something on the floor (see PMID: 12444880 for more details). Each activity is rated from 0 to 3, and the five scores are added up (min = 0, max = 15; a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Five times sit-to-stand test
The five times sit-to-stand test will be used as performance based outcome of physical function. Participant sitting on a supported chair will be instructed to stand and sit again as fast as possible, five times in a row. Time will be measured in seconds. The test will be performed twice and the average time for the two trials will be recorded (a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Depression
Depression levels will be measured using the French-Canadian version of the Beck Depression Inventory (BDI; min = 0, max = 63; a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Anxiety
Anxiety levels will be measured using the French-Canadian version of the State-Trait Anxiety Inventory, version Y (STAI-Y; min = 20, max = 80; a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Pain catastrophizing
The main elements contributing to the pain experience according to the fear avoidance model of pain will be measured. Pain catastrophizing will be measured with the French-Canadian version of the pain catastrophizing scale (PCS; min = 0, max = 52; a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Kinesiophobia
The main elements contributing to the pain experience according to the fear avoidance model of pain will be measured. Pain-related fear will be measured with a French adaptation of the Tampa scale for kinesiophobia (TSK; min = 17, max = 68; a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Pain vigilance
The main elements contributing to the pain experience according to the fear avoidance model of pain will be measured. Hypervigilance will be measured with a French adaptation of the pain vigilance and awareness questionnaire (PVAQ; min = 0, max = 80; a higher score means a worse outcome).
Time frame: baseline, 4- and 12-weeks post-randomization.
Patient's global impression of change
Participants will be instructed to give their global impression of change on a scale from -100 to 100 (-100 = very much worse, 0 = no change, 100 = very much improved).
Time frame: After the last treatment session (12-weeks post-randomization)
Expectations of pain relief
Participants will be instructed to rate their expectations of pain relief after the treatment on a scale from 0 to 100, 0 being "no relief" and 100 being "complete relief".
Time frame: baseline and 4-weeks post-randomization.
Contextual factors (healing encounters and attitudes lists (HEAL))
Contextual factors will be measured using a French adaptation of the healing encounters and attitudes lists (HEAL).
Time frame: baseline, 4- and 12-weeks post-randomization.
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