Effect of Spinal Manipulative and Mobilization Therapies in Young Adults With Mild to Moderate Chronic Low Back Pain
Thomas JS, Clark BC, Russ DW, Ploutz‐Snyder R, Corcos DM. Effect of spinal manipulative and mobilization therapies in young adults with mild to moderate chronic low back pain. JAMA Network Open. 2020;3(8):e2012589. doi:10.1001/jamanetworkopen.2020.12589Link to Original Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7407093/
Key Points
1. Low back pain (LBP) is a common reason for seeking medical care, and manipulative therapies are frequently used to treat it.
2. The RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study compared the effectiveness of spinal manipulation, spinal mobilization, and placebo (sham cold laser) in reducing pain and disability in young adults with chronic LBP.
3. The study, conducted at the Ohio Musculoskeletal and Neurological Institute at Ohio University, involved 162 participants with mild to moderate chronic LBP and low self-reported disability who received 6 treatment sessions over a 3-week period.
4. The primary outcome measures were the change in Numerical Pain Rating Scale (NPRS) score and the change in disability assessed with the Roland-Morris Disability Questionnaire 48 to 72 hours after completion of the treatments.
5. The study found no significant difference in pain and disability reduction between spinal manipulation, spinal mobilization, and placebo, indicating that neither spinal manipulation nor spinal mobilization appeared to be effective treatments for mild to moderate chronic LBP in the studied cohort.
6. The study concluded that manipulative therapy techniques were no more effective than a well-chosen placebo in reducing pain and disability in patients with chronic low back pain. These findings provide evidence about the limits of manipulative therapies in chronic low back pain and highlight the importance of selecting an effective placebo in future trials on manipulative therapy.
Introduction
The introductory section of the research paper highlights the significant prevalence and financial burden of chronic low back pain, which accounts for a substantial portion of healthcare costs in the US. Manipulative therapies, including manipulation-based and mobilization-based techniques, are commonly used to address low back pain, with substantial out-of-pocket costs to patients. Spinal manipulative techniques involve a high-velocity, low-amplitude force that results in one or more spinal cavitation, while spinal mobilization techniques are low velocity, low force manual therapies that do not produce an audible sound. While evidence supports the clinical effectiveness of manipulative therapies for acute and subacute low back pain, the effectiveness for chronic low back pain is less clear, with conflicting results from existing studies. Furthermore, previous studies have generally compared manipulative therapies to standard care or waiting list controls, with few directly comparing the clinical effectiveness of manipulation-based and mobilization-based techniques.
The RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study was conducted to address these gaps in knowledge, serving as a phase II randomized clinical trial comparing the effectiveness of spinal manipulation, spinal mobilization, and a placebo (sham laser) for treating pain and disability in young adults with chronic low back pain. The paper sets the stage for the need to understand the relative effectiveness of these manipulative therapies, as well as the importance of employing a stronger control group, given the prevalence of these techniques in clinical practice.
Methods
Study Design
The RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study was a phase II randomized clinical trial focused on comparing the effectiveness of spinal manipulation, spinal mobilization, and placebo (sham laser) in the treatment of pain and disability in young adults with chronic low back pain. The trial utilized a single-blinded (investigator-blinded) and placebo-controlled design. The participants were randomized in a 1:1:1 ratio into one of the three groups using computer generated randomization.
The spinal mobilization group underwent spinal manipulation treatment twice a week for three weeks. The spinal mobilization group also received spinal mobilization treatment twice a week for three weeks. The placebo group received sham cold laser treatment twice a week for three weeks.
Study Participants
In the RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study, 162 patients with chronic low back pain were randomly assigned to three treatment groups, each consisting of 54 patients. The inclusion criteria for the study required participants to be between 18 and 45 years of age, experience constant or frequent low back pain for the past 3 months, seek care from a healthcare practitioner for their low back pain, report an average pain score of at least 2 on a scale of 0 to 10, and have a minimum Roland-Morris Disability Questionnaire score of 4. Additionally, all potential participants underwent a physical exam to confirm the presence of at least 3 of 4 clinical characteristics associated with a positive response to spinal manipulation. Clinical characteristics for positive response to spinal manipulation include symptoms <16 days, no symptoms distal to the knee, low fear avoidance behavior, 1 or more hypomobile vertebral segment, and 1 or more hip with IR >35 degrees. The trial excluded individuals with symptom duration of less than 16 days. The participants were prohibited the use of narcotics, muscle relaxants, manipulation, mobilization, acupuncture, or massage treatments during the trial. Participants were allowed to use over-the-counter pain relief medications and apply heat or ice packs.
Participant Recruitment
A total of 4,903 individuals were recruited via print and media advertisements to assess their eligibility for the study. Among these, 4,741 individuals were excluded from the study due to insufficient pain level, insufficient duration of symptoms, receiving prohibited interventions, or falling outside the age criteria for inclusion. Ultimately, only 182 individuals met the initial study criteria. In order to create a more homogeneous group, individuals with obesity (BMI > 35kg/m^2) were subsequently excluded, resulting in a final sample size of 162 participants.
Study Timeline
The RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study enrolled eligible participants with chronic low back pain who were randomized into an intervention group. Baseline clinical measures were obtained before a treatment intervention, which was followed by the immediate repetition of these measures. The study provided baseline measures to characterize the sample. Participants received a total of 6 treatments over 3 weeks, and prior to the second treatment, their expectations for treatment success were assessed using a credibility and expectancy questionnaire. This questionnaire included 7 questions with a 9-point Likert scale to gauge participant confidence in the potential of the treatment to alleviate their symptoms. This instrument is commonly used to evaluate the strength of the placebo treatment group in randomized trials. Following the final treatment, participants returned to the laboratory for a follow-up assessment of all clinical measures (primary end point) 2 to 5 days later. Approximately 4 weeks after their last treatment, participants returned for a follow-up assessment of the clinical outcome measures. This study timeline outlines the enrollment, randomization, treatment interventions, immediate repetition of clinical measures, credibility and expectancy questionnaire, and follow-up assessments conducted in the RELIEF study, providing a comprehensive overview of the study's procedures from enrollment to the final follow-up assessment.
Study Interventions
Spinal Manipulation Treatment
The study intervention for spinal manipulation involved positioning the participant on their side with the painful side facing upwards. The clinician then flexed the participant's hips and knees to induce lumbar spine flexion, followed by passive rotation of the participant's torso in the opposite direction. A rapid thrust was applied to the shoulder and pelvis to create a rotation force couple on the hypomobile segment, with the goal of producing an audible pop or cavitation. If no cavitation occurred after two attempts on each side (four attempts total), the treatment was considered complete.
Spinal Mobilization Treatment
The spinal mobilization treatment in the study involved positioning the participant in a same manner as the spinal manipulation technique with the clinician’s hand placed on the anterior shoulder and the other hand on the posterior pelvis. The participant was instructed to gently push the shoulder and pelvis into the clinician's hands, creating an isometric rotation of the torso, which generated a rotation force couple on the hypomobile segment. The participant was asked to hold this contraction for a minimum of 7 seconds and up to 60 seconds if tolerable. If a cavitation occurred or the clinician detected a release in tissue tension, the treatment was considered complete; otherwise, the clinician adjusted the position and repeated the treatment for up to 10 minutes.
Placebo (Sham Laser) Treatment
The laser manufacturer provided a device that did not emit significant light or heat, but it appeared to be functional to both participants and clinicians. The sham laser was administered on the same position as spinal manipulation and mobilization techniques, targeting the painful spinal vertebral segment.
Practitioners, Adherence, and Safety Assessments
In the RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study, licensed clinicians with at least 3 years of experience in manipulative therapies, specifically doctors of osteopathic medicine or physical therapists, administered the treatments. To uphold treatment consistency, the study team conducted an annual workshop to ensure conformity to the prescribed interventions. Adherence to the treatment protocol was considered successful if a participant received at least 5 out of the 6 treatments. Additionally, adverse events, encompassing any negative changes in health status, were meticulously documented at every visit. Attribution and grading of these adverse events were determined in accordance with the National Cancer Institute's Common Terminology Criteria for Adverse Events.
Statistical Analysis
In the Statistical Analysis section of the paper, the sample size calculations were based on previous studies of spinal manipulation, using a Cohen d effect size of 0.5 to determine that 54 subjects per treatment group would be sufficient to achieve the desired statistical power. The primary hypotheses were that both the spinal manipulation and spinal mobilization groups would show a significantly larger reduction in Roland-Morris Disability Questionnaire score compared to the placebo group. One-tailed tests were used to assess these directional hypotheses.
Clinically important differences were defined as a 2-point reduction in NPRS score and a 3-point reduction in Roland-Morris Disability Questionnaire score. The statistical significance threshold was set at P < .05.
The data were examined to ensure normal distribution of random intercepts and slopes, as well as homogeneity of residual variances across the three treatment groups. The main analytic framework was linear mixed-effects regression analyses, which incorporated various factors as random effects.
Maximum-likelihood estimation allowed participants with missing data to be included in the model under certain conditions. The regression models incorporated random intercept terms and fixed-factor parameters for the main effects of group and time, as well as the interaction terms of group by time. Biological sex was included in each model.
A priori contrasts comparing changes from baseline between the two intervention groups were performed, with Holm alpha adjustments to preserve the familywise error rates at 0.05.
Intention-to-Treat Analysis<
The intention-to-treat (ITT) analysis in the RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study included all randomized study participants who had at least a baseline assessment. The participants were enrolled and randomized following an in-person physical examination, after which baseline measures were completed in a follow-up visit within 7 days of the screening. It was noted that four randomized participants dropped out before baseline measures, which impacted the strict definition for ITT analysis. Consequently, a near ITT analysis was utilized as the primary method for assessing outcomes, and maximum-likelihood estimation was employed to estimate any missing observations. It is essential to consider that the primary analysis did not strictly fulfill the requirements for ITT analysis due to the dropouts before baseline measures, which led to the utilization of a modified approach to accommodate the missing observations.
Per-Protocol Analysis
The participants were excluded from Per-Protocol Analysis (PPA) if they attended <5 treatment sessions, received prohibited interventions during the study, developed an exclusionary medical condition. The study found no difference between ITT and PPA, thus only the results of the ITT analysis were present.
Results
A total of 92 women and 70 men, with a mean age of 25.0 years, were enrolled in the study. During the baseline assessment, participants reported a pain level of 4.3 out of 10 in the past 7 days, with a mean score of 9.9 on the Roland-Morris Disability Questionnaire. The average length of chronic low back pain was 6.2 years. Two participants from the spinal manipulation group, one participant from the spinal mobilization group, and one participant from the placebo group withdrew from the study due to scheduling issues. Additionally, five participants did not complete the treatment and follow-up visits.
Primary Outcomes
The RELIEF (Researching the Effectiveness of Lumbar Interventions for Enhancing Function) Study, a phase II randomized clinical trial, examined the effectiveness of spinal manipulation, spinal mobilization, and placebo (sham laser) in treating pain and disability in young adults with chronic low back pain. The study found no significant difference in the change in pain scores between spinal manipulation and spinal mobilization, spinal manipulation and placebo, or spinal mobilization and placebo. Similarly, there was no significant difference in the change in self-reported disability scores between spinal manipulation and spinal mobilization, spinal manipulation and placebo, or spinal mobilization and placebo. Additionally, four participants withdrew after randomization due to scheduling issues, resulting in incomplete baseline measures and treatment/follow-up assessments. The study used various assessment tools including weight, depression scale, kinesiophobia scale, numerical pain rating scale, and the Roland-Morris Disability Questionnaire to measure and analyze the outcomes. The results suggest that there were no statistically significant differences in pain or disability outcomes among the three treatment groups at the primary endpoint. These findings underscore the need for further research and stronger control groups in trials evaluating the effectiveness of manipulative therapies for chronic low back pain.
Treatment Expectancy
In the Treatment Expectancy section of the research paper, the comparison of treatment credibility and expectancy ratings across groups did not yield statistically significant differences. This implies that participants in each group had similar expectations regarding the likely benefit of their assigned treatment. The study also examined the relationship between individual treatment expectancy ratings obtained before the second treatment session and changes in pain ratings. The overall findings revealed an inverse correlation between treatment expectancy scores and the change in pain ratings, suggesting that individuals with higher expectations of treatment success reported larger decreases in pain with treatment. When these expectancy effects were analyzed within each treatment group, significant inverse correlations were observed for the placebo and spinal manipulation groups, but not for the spinal mobilization group. Furthermore, the changes in Roland-Morris Disability Questionnaire ratings were not significantly associated with treatment expectancy. These results indicate that higher treatment expectancy was linked to greater reductions in pain for the overall sample, with similar associations seen in the placebo and spinal manipulation groups. However, no significant relationship was found between treatment expectancy and changes in disability questionnaire ratings.
Discussion
The RELIEF Study is a randomized clinical trial that compared the effectiveness of spinal manipulation, spinal mobilization, and a placebo (sham cold laser) for treating chronic low back pain in young adults. The study found no significant differences in pain and disability reduction among the three treatment groups immediately after the 3-week treatment and at the 4-week follow-up. Despite prior hypotheses that manipulative therapy techniques would be more effective, the data did not support this. Although manipulative therapy has shown effectiveness for acute and subacute low back pain, its effectiveness for chronic low back pain is inconclusive. An attempt to modify a clinical prediction rule did not significantly improve the outcomes. The study suggests that manipulative therapies were not more effective than an effective placebo for mild to moderate chronic low back pain, and it raises doubts about the suitability of manipulative therapy for chronic back pain in young adults. It is important to note that a reductionist approach was used to deliver the interventions. In the clinical settings, it is questionable whether this approach to deliver interventions in the clinic can be debated. Additionally, the study highlights the importance of an effective placebo control and the impact of patient expectations on treatment outcomes. The findings suggest that the placebo used in the study was effective and underscore the need for carefully selecting and evaluating control treatments in manipulative therapy trials. These results contribute to the understanding of the limitations of manipulative therapies in chronic low back pain and emphasize the importance of placebo effectiveness and patient expectations in evaluating treatment outcomes.
Limitations
The RELIEF study, a phase II randomized clinical trial comparing spinal manipulation, spinal mobilization, and placebo (sham laser) for chronic low back pain in young adults, has several limitations. The participants were relatively young adults with mild to moderate chronic low back pain and low self-reported disability, potentially representing an understudied cohort. Additionally, while the trial used a single-blinded design to minimize bias, a true double-blind design was impossible due to the nature of manual therapies. The study's interventions were restricted to the isolated application of manipulation, mobilization, or placebo, limiting the examination of potential additive benefits from other interventions. Furthermore, the average duration of symptoms in the cohort was over 6 years, suggesting a need for more data on treatment effectiveness for manual therapies in this population. Future research using a pragmatic clinical trial design approach could offer further insights into the potential benefits of these manual therapies, as well as the potential benefits of additional interventions like stretching and strengthening exercises.
Opportunities for Future Research
1. Investigate the effectiveness of spinal manipulation and spinal mobilization in reducing pain and disability in individuals with more severe chronic low back pain. This study focused on young adults with mild to moderate chronic low back pain, so further research could explore the impact of these treatments on individuals with more severe symptoms.
2. Assess the potential additive benefits of manual therapies, such as manipulation and mobilization, when used in combination with other interventions, such as stretching and strengthening exercises. A pragmatic clinical trial design could provide insights into the effectiveness of these combined approaches in managing chronic low back pain.
3. Explore the effectiveness of manipulative therapy techniques for individuals with chronic low back pain across different age cohorts, including middle-aged and older adults. Understanding the potential differences in treatment effectiveness among various age groups could provide valuable insights for clinical practice.
4. Examine the impact of treatment expectancy on outcomes of manipulative therapy techniques. Further research could investigate the relationship between participants' expectations of treatment success and the observed changes in pain and disability following manipulative therapy interventions.
5. Evaluate the effectiveness of the placebo control used in manipulative therapy studies. Future studies could focus on assessing the adequacy of blinding and the impact of treatment expectations on the outcomes of placebo-controlled trials in the context of manipulative therapy research.
6. Investigate the potential factors contributing to the lack of effectiveness of spinal manipulation and spinal mobilization for mild to moderate chronic low back pain observed in this study. This could include exploring patient characteristics, treatment delivery methods, and participant adherence to the treatment protocols.
These opportunities for future research build upon the findings and limitations of the provided article, aiming to further enhance the understanding of manipulative therapy techniques in the management of chronic low back pain.
