A Randomized Clinical Trial Comparing
Chiropractic Adjustments to Muscle Relaxants
for Subacute Low Back Pain

This section is compiled by Frank M. Painter, D.C.
Send all comments or additions to:

FROM:   J Manipulative Physiol Ther 2004 (Jul); 27 (6): 388-398 ~ FULL TEXT

Kathryn T. Hoiriis, DC, Bruce Pfleger, PhD, Frederic C. McDuffie, MD,
George Cotsonis, MA, Omar Elsangak, MBBCh, DC, Roger Hinson, DC,
Gregoria T. Verzosa, DC

College of Chiropractic,
Chiropractic Sciences Division,
Life University,
Marietta, Ga 30060, USA.

Researchers compared the relative efficacy of chiropractic adjustments with muscle relaxants and placebo/sham for sub-acute low back pain (two- to six-weeks duration). They found chiropractic was more beneficial than placebo in reducing pain and more beneficial than either placebo or muscle relaxants in reducing the global impression of severity scale (GIS).

See also:

The Use of Muscle Relaxant Medications in Acute Low Back Pain
Spine (Phila Pa 1976) 2004 (Jun 15);   29 (12):   1346–1351

This paper found that muscle relaxant users had somewhat slower recovery from their episode of back pain.

BACKGROUND:   The adult lifetime incidence for low back pain is 75% to 85% in the United States. Investigating appropriate care has proven difficult, since, in general, acute pain subsides spontaneously and chronic pain is resistant to intervention. Subacute back pain has been rarely studied.

OBJECTIVE:   To compare the relative efficacy of chiropractic adjustments with muscle relaxants and placebo/sham for subacute low back pain.

DESIGN:   A randomized, double-blind clinical trial.

METHODS:   Subjects (N = 192) experiencing low back pain of 2 to 6 weeks' duration were randomly allocated to 3 groups with interventions applied over 2 weeks. Interventions were either chiropractic adjustments with placebo medicine, muscle relaxants with sham adjustments, or placebo medicine with sham adjustments. Visual Analog Scale for Pain, Oswestry Disability Questionnaire, and Modified Zung Depression Scale were assessed at baseline, 2 weeks, and 4 weeks. Schober's flexibility test, acetaminophen usage, and Global Impression of Severity Scale (GIS), a physician's clinical impression used as a secondary outcome, were assessed at baseline and 2 weeks.

RESULTS:   Baseline values, except GIS, were similar for all groups. When all subjects completing the protocol were combined (N = 146), the data revealed pain, disability, depression, and GIS decreased significantly (P <.0001); lumbar flexibility did not change. Statistical differences across groups were seen for pain, a primary outcome, (chiropractic group improved more than control group) and GIS (chiropractic group improved more than other groups). No significant differences were seen for disability, depression, flexibility, or acetaminophen usage across groups.

CONCLUSION:   Chiropractic was more beneficial than placebo in reducing pain and more beneficial than either placebo or muscle relaxants in reducing Global Impression of Severity Scale (GIS).

From the FULL TEXT Article:


In all groups, for each outcome measure, there was improvement after 2 weeks of care and further improvement at the 4-week follow-up, so these subacute subjects appear to improve in a manner similar to acute pain sufferers. [4, 5] The improvements in the placebo group likely represent natural history.

After the 2-week intervention phase, chiropractic adjustments were shown to be statistically more beneficial than placebo in reducing pain and more beneficial than placebo or muscle relaxants in reducing GIS; however, there were no differences across groups for disability. For the disability measure, post hoc analysis revealed the power of the present study to be 59%. Further, assuming means and variances seen in the present study and a power level of 80%, increasing the sample population to 72 subjects per group could have yielded significant advantages for chiropractic adjustments. No group differences were seen with the Modified Zung, as would be expected since depression is mild during the acute/subacute phase, nor were differences observed for flexibility or analgesic usage.

Previous comparisons of SMT to medical care for LBP have shown mixed results. A study of subjects with 3 to 26 weeks of LBP showed no additional benefit for osteopathic manipulation over standard medical care, which included medicines and physical modality. [33] Similarly, a study of acute LBP showed manipulative physiotherapy was no more beneficial than nonsteroidal anti-inflammatory drugs (NSAIDs). [54] In chronic LBP, no group differences were seen for trunk-strengthening exercises supplemented by either chiropractic manipulation or NSAIDs. [55] Conversely, other chronic spinal pain studies have shown spinal manipulative procedures more beneficial than NSAIDs [18] and spinal manipulation more beneficial than continued care using analgesics and NSAIDs. [15] In light of the differing methodologies across studies, it is difficult to draw any strong conclusions.

In this study, care was restricted to 2 weeks, although in practice, chiropractors typically see patients for longer periods. Other trials comparing chiropractic adjustments to medical care for LBP allowed for 9 visits over 1 month, [56] 10 treatments over 1 year,16 or, in a childhood asthma study, 20 to 36 visits over 4 months. [57] Though improvement was marked and rapid in the present trial, providing the chiropractors with more latitude in their care plan might have provided additional benefit. As follow-up extended only to 4 weeks, long-term benefits of the interventions are unknown.

Outcomes in randomized drug therapy trials often include assessment of global improvement and 5 specific domains of back pain: local pain, muscle spasm, range of motion, tenderness to palpation, and activities of daily living. [58] The GIS used in this study has not been tested for reliability and validity and is subjective by its very nature. It is, therefore, limited in its usefulness and significance. The measure did provide a broadly based assessment, was normally distributed, demonstrated a useful range, and was responsive to 2 weeks of intervention/time. In a clinical perspective, the severity of a patient presenting for care is often subjectively rated. In this study, the GIS represented a blinded evaluation of severity by the medical doctor using his own scoring method. There was overlap in outcome assessments, since GIS was formed from 5 measures, 2 of which were analyzed individually. However, analysis of GIS data without the VAS or Schober's components did not change the results. The GIS showed that subjects given chiropractic adjustments and placebo medicine improved more than subjects who received placebo medicine or muscle relaxants did (in combination with sham adjustments). However, it should be noted that the chiropractic group mean was worse at baseline, giving a slightly more favorable advantage toward improvement based solely on natural history.

In this study population, only modest changes in flexibility were seen and no difference among groups emerged using Schober's test. The reliability and validity of Schober's test for testing lumbar flexibility have been debated. Researchers have found Schober's test works as well as the computerized CA-6000 Spinal Motion Analyzer (Orthopedic Systems Inc, Union City, Calif) in assessing lumbar flexion and that a modified Schober test is superior to double inclinometer methods for flexion, while another study suggests use of a modified Schober could introduce systematic errors and its use is questionable. [59-61]

Although lifetime usage figures are not available, approximately 7% to 10% of the overall population uses chiropractic in a given year. [62, 63] The study population was not naοve to chiropractic interventions. Since 40% also reported previous LBP (exclusion criteria: occurrence >18 months prior), it is not surprising to find a 41% lifetime history of chiropractic care (exclusion: occurrence >18 months prior). Even so, the post hoc analysis found no significant association of previous chiropractic care with blinding, dropout rate, or changes in VAS for pain.

Although blinding procedures directed toward the providers and assessors were successful, whether subjects remained blinded is debatable. A high percentage of subjects in the chiropractic and medical groups responded correctly to questions regarding the intervention received. This is not unusual in clinical trials, since many interventions deliver a powerful and readily apparent effect. However, it is difficult to interpret why statistically more control subjects than chiropractic subjects in this study thought they were receiving true medications. It would seem that the blinding procedures used here were no less successful than those used in other rigorous randomized clinical trials. [56, 57, 64]

Blinded, randomized clinical trials are considered the gold standard of experimental design. [9, 15, 21, 65] Yet, blinding remains elusive in studies where the intervention may be invasive (eg, surgery, acupuncture) or involve physical contact between the subject and the care provider (eg, chiropractic, osteopathy, massage). An appropriate chiropractic sham procedure requires a maneuver that makes subjects think they are getting a spinal adjustment without actually causing osseous rearrangement. Joint cavitation commonly occurs during activities that approach endpoint range of motion, and this may cause changes in the spine. Joint cavitation was noted twice in the present study during lumbar sham procedures. Even well-designed sham procedures could cause inadvertent correction. Further, there is the possibility that palpation of spastic paraspinal muscles and other contiguous tissues may cause spinal changes. Thus, previous rigorous sham-controlled studies in chiropractic that demonstrated global benefits to all intervention groups while failing to show differential benefits [57] may have been inadvertently providing benefit to the control group.

Study Limitations

In a factorial design, a fourth group could have been randomized to receive both active interventions. Furthermore, this study did not provide for a 1-year follow-up. Possibly, long-term follow-up could help to identify different recovery patterns in these groups. Stratification on the study population for the wide ranges in pain and disability scores (large SD) in a separate analysis may provide characteristics of responders versus nonresponders for both types of interventions.

Health care providers often rate the severity of presenting complaints of patients using subjective means. The GIS used for a blinded assessment by the medical physician needs to be tested for reliability and validity; therefore, the significance of the results for GIS should be interpreted cautiously.

Increasing the sample size according to power analysis, lengthening the care phase to 6 weeks to provide care more in line with practice standards, and providing a 1-year follow-up would improve future studies.


This study identified a sample population of subacute low back pain sufferers for which chiropractic care provided an equally effective management to the conservative medical care of muscle relaxants. However, as subjects responded well to time (and placebo), these design changes may not provide the strong clinical evidence needed to recommend a particular intervention for management of subacute back pain.

Statistically, the chiropractic group responded significantly better than the control group with respect to a decrease in pain scores.


  1. Allan, DB and Waddell, G.
    An historical perspective on low back pain and disability.
    Acta Orthop Scand. 1989; 60: 1–23

  2. Andersson, GBJ.
    Epidemiology of low back pain.
    Acta Orthop Scand. 1998; 69: 28–31

  3. Waddell, G.
    Low back pain: a twentieth century health care enigma.
    Spine. 1996; 21: 2820–2825

  4. Linton, SJ and Hallden, K.
    Can we screen for problematic back pain? A screening questionnaire for predicting outcome in acute and subacute back pain.
    Clin J Pain. 1998; 14: 209–215

  5. Sinclair, SJ, Hogg-Johnson, S, Mondloch, MV, and Shields, SA.
    The effectiveness of an early active intervention program for workers with soft-tissue injuries: the early claimant cohort study.
    Spine. 1997; 22: 2919–2931

  6. Carey TS, Garrett J, Jackman A, et al.
    The Outcomes and Costs of Care for Acute Low Back Pain Among Patients
    Seen by Primary Care Practitioners, Chiropractors, and Orthopedic Surgeons

    New England J Medicine 1995 (Oct 5); 333 (14): 913–917

  7. Deyo, RA and Phillips, WR.
    Low back pain. A primary care challenge.
    Spine. 1996; 21: 2826–2832

  8. Von Korff, M and Saunders, K.
    The course of back pain in primary care.
    Spine. 1996; 21: 2833–2839

  9. Stanley J. Bigos, MD, Rev. O. Richard Bowyer, G. Richard Braen, MD, et al.
    Acute Lower Back Problems in Adults. Clinical Practice Guideline No. 14.
    Rockville, MD: Agency for Health Care Policy and Research, [AHCPR Publication No. 95-0642].
    Public Health Service, U.S. Department of Health and Human Services; 1994

  10. Abenhaim, L and Bergeron, AM.
    Twenty years of randomized clinical trials of manipulative therapy for back pain: a review.
    Clin Invest Med. 1992; 15: 527–535

  11. Haldeman, S.
    Spinal manipulative therapy in sports medicine.
    Clin Sports Med. 1986; 5: 277–293

  12. Moritz, U.
    Evaluation of manipulation and other manual therapy. Criteria for measuring the effect of treatment.
    Scand J Rehabil Med. 1979; 11: 173–179

  13. Raftis KL, Warfield CA.
    Spinal manipulation for back pain.
    Hosp Pract (Off Ed) 1989;24:89-90, 95-6, 102.

  14. Shekelle, PG, Adams, AH, Chassin, MR, Hurwitz, EL, and Brook, RH.
    Spinal manipulation for low back pain.
    Ann Intern Med. 1992; 117: 590–598

  15. Koes, BW, Bouter, LM, van Mameren, H, Essers, AH, Verstegen, GM, Hofhuizen, DM et al.
    The effectiveness of manual therapy, physiotherapy, and treatment by the general practitioner for nonspecific back and neck complaints.
    Spine. 1992; 17: 28–35

  16. Meade TW, Dyer S, Browne W, et al:
    Randomised Comparison of Chiropractic and Hospital Outpatient
    Management for Low Back Pain: Results from Extended Follow up

    British Medical Journal 1995 (Aug 5); 311 (7001): 349–351

  17. Meade TW, Dyer S, Browne W, et al:
    Randomised Comparison of Chiropractic and Hospital Outpatient Management
    for Low Back Pain: Results from Extended Follow up

    British Medical Journal 1995 (Aug 5); 311 (7001): 349–351

  18. Lynton G. F. Giles; Reinhold
    Chronic Spinal Pain Syndromes: A Clinical Pilot Trial Comparing Acupuncture,
    a Nonsteroidal Anti-inflammatory Drug, and Spinal Manipulation

    J Manipulative Physiol Ther 1999 (Jul); 22 (6): 376–381
    This is the first of 3 articles in Giles brilliant Chronic Spinal Pain review

  19. Hsieh, CY, Phillips, RB, Adams, AH, and Pope, MH.
    Functional outcomes of low back pain: comparison of four treatment groups in a randomized controlled trial.
    J Manipulative Physiol Ther. 1992; 15: 4–9

  20. Pengel, HM, Maher, CG, and Refshauge, KM.
    Systematic review of conservative interventions for subacute low back pain.
    Clin Rehabil. 2002; 16: 811–820

  21. Anderson, R, Meeker, WC, Wirick, BE, Mootz, RD, Kirk, DH, and Adams, A.
    A meta-analysis of clinical trials of spinal manipulation.
    J Manipulative Physiol Ther. 1992; 15: 181–194

  22. Gatterman, MI.
    What's in a word?.
    in: MI Gatterman (Ed.) Foundations of chiropractic: subluxation.
    Mosby-Year Book, St. Louis; 1995: 5–17

  23. Janse, J.
    History of the development of chiropractic concepts: chiropractic terminology.
    (National Institutes of Health NINCDS Monograph 15)
    in: M Goldstein (Ed.) The research status of spinal manipulative therapy.
    US Department of Health, Education, and Welfare.
    Public Health Service, Bethesda (MD); 1975: 25–42

  24. Leach, RA.
    Manipulation terminology.
    in: RA Leach (Ed.) The chiropractic theories: principles and clinical applications. 3rd ed.
    Williams and Wilkins, Baltimore; 1994: 15–22

  25. Meeker, W., & Haldeman, S. (2002).
    Chiropractic: A Profession at the Crossroads of Mainstream and Alternative Medicine
    Annals of Internal Medicine 2002 (Feb 5); 136 (3): 216–227

  26. Christensen MG, Kerkhoff D, Kollasch MW.
    Job Analysis of Chiropractic 2000
    Greeley (CO): National Board of Chiropractic Examiners, 2000.

  27. Nyiendo, J, Haas, M, and Goodwin, P.
    Patient Characteristics, Practice Activities, and One-month Outcomes for Chronic,
    Recurrent Low-back Pain Treated by Chiropractors and Family Medicine Physicians:
    A Practice-based Feasibility Study

    J Manipulative Physiol Ther 2000 (May); 23 (4): 239–245

  28. Hoiriis, KT and Owens, EF.
    Changes in general health status during upper cervical chiropractic care: a practice-based research project update.
    Chiropr Res J. 1999; 6: 65–70

  29. Henderson, C.
    Three neurophysiologic theories on the chiropractic subluxation.
    in: MI Gatterman (Ed.) Foundations of chiropractic: subluxation.
    Mosby, St. Louis; 1995: 225–233

  30. Lantz, C.
    The vertebral subluxation complex.
    in: M Gatterman (Ed.) Foundations of chiropractic: subluxation.
    Mosby, St. Louis; 1995: 149–174

  31. Miller, KE, Douglas, VD, Richards, AB, Chandler, MJ, and Foreman, RD.
    Propriospinal neurons in the C1-C2 spinal segments project to the L5-S1 segments of the rat spinal cord.
    Brain Res Bull. 1998; 47: 43–47

  32. Arkuszewski, Z.
    Involvement of the cervical spine in back pain.
    Man Med. 1986; 2: 126–128

  33. Andersson, GBJ, Lucente, T, Davis, AM, Kappler, RE, Lipton, JA, and Leurgans, S.
    A comparison of osteopathic spinal manipulation with standard care for patients with low back pain.
    N Engl J Med. 1999; 341: 1426–1431

  34. Grostic JD.
    Upper cervical care and functional leg length inequality.
    Proceedings of the Sixth Annual Conference on Research and Education. 1991 June 21-23;
    Monterey, California. San Jose (CA):
    Consortium for Chiropractic Research; 1991. p. 70-3.

  35. Grostic, JD and DeBoer, KF.
    Roentgenographic measurement of atlas laterality and rotation:
    a retrospective pre and post manipulation study.
    J Manipulative Physiol Ther. 1982; 5: 63–69

  36. in: OC Reinert (Ed.)
    Chiropractic procedure and practice.
    Marian Press, Florissant (MO); 1976: 78–95

  37. in: JW Downe (Ed.)
    Technique manual of Life College, School of Chiropractic.
    Life University, Marietta (GA); 1993: 14–34

  38. Hinson, R and Brown, S.
    Supine leg length differential estimation: an inter- and intra-examiner reliability study.
    Chiropr Res J. 1998; 5: 17–22

  39. Hinson, R and Pfleger, B.
    Pre- and post-adjustment supine leg-length estimation.
    J Chiropr Educ. 2000; 14: 37–38

  40. Walsh P. Physicians' desk reference. 55th ed.
    Montvale (NJ): Medical Economics; 2001. p. 1929, 2716, 3252.

  41. Jayson, MIV.
    Outcome measures for back pain: introduction, justification, and epidemiology.
    in: GE Erhlich, NG Khaltaev (Eds.)
    Low Back Pain Initiative
    The World Health Organisation. 1999

  42. Ferraz, MB, Quaresma, MR, Aquino, LR, Atra, E, Tugwell, P, and Goldsmith, CH.
    Reliability of pain scales in the assessment of literate and illiterate patients with rheumatoid arthritis.
    J Rheumatol. 1990; 17: 1022–1024

  43. McCormack, HM, Horne, DJ, and Sheather, S.
    Clinical applications of visual analogue scales: a critical review.
    Psychol Med. 1988; 18: 1007–1019

  44. Scott, J and Huskisson, EC.
    Vertical or horizontal visual analogue scales.
    Ann Rheum Dis. 1979; 38: 560

  45. Baker, DJ, Pynsent, PB, and Fairbank, JCT.
    The Oswestry Disability Index revisited: its reliability, repeatability and validity, and a comparison with the St Thomas Disability Index.
    in: MO Roland, JR Jenner (Eds.)
    Back pain: new approaches to rehabilitation and education.
    Manchester University Press,
    Manchester, England; 1989: 174–186

  46. Fairbank, JCT, Couper, J, Davies, JB, and O'Brien, JP.
    The Oswestry Low Back Pain Disability Questionnaire.
    Physiotherapy. 1980; 66: 271–273

  47. Stratford, PW, Binkley, J, Solomon, P, Gill, C, and Finch, E.
    Assessing change over time in patients with low back pain.
    Phys Ther. 1994; 74: 528–533

  48. Hedlund, JL and Vieweg, BW.
    The Zung Self-rating Depression Scale: a comprehensive review.
    J Oper Psychiatry. 1979; 10: 51–64

  49. Lambert, MJ, Hatch, DR, Kingston, MD, and Edwards, BC.
    Zung, Beck, and Hamilton rating scales as measures of a treatment outcome: a meta-analytic comparison.
    J Consult Clin Psychol. 1986; 54: 54–59

  50. Main, CG, Wood, PLR, Hollis, S, Spanswick, CC, and Waddell, G.
    The distress and risk assessment method: a simple patient classification to identify distress and evaluate the risk of poor outcome.
    Spine. 1992; 17: 42–52

  51. Tanaka-Matsumi, J and Kameoka, VA.
    Reliabilities and concurrent validities of popular self-report measures of depression, anxiety, and social desirability.
    J Consult Clin Psychol. 1986; 54: 328–333

  52. Dequeker, J, Panayi, G, Pinus, T, and Grahame, R.
    in: Medical management of rheumatic musculoskeletal and connective tissue disease.
    Marcel Dekker, New York; 1997: 41

  53. Evans, RC.
    Schober's test.
    in: RC Evans (Ed.) Illustrated essentials in orthopedic assessment.
    Mosby, St. Louis; 1994: 326–327

  54. Waterworth, RF and Hunter, IA.
    An open study of diflunisal, conservative and manipulative therapy in the management of low back pain.
    N Z Med J. 1985; 98: 372–375

  55. Bronfort G, Goldsmith CH, Nelson CF, Boline PD, Anderson AV.
    Trunk Exercise Combined with Spinal Manipulative or NSAID Therapy
    for Chronic Low Back Pain: A Randomized, Observer-blinded Clinical Trial

    J Manipulative Physiol Ther. 1996 (Nov); 19 (9): 570–582

  56. Cherkin, DC, Deyo, RA, Battie, M, Street, J, and Barlow, W.
    A Comparison of Physical Therapy, Chiropractic Manipulation, and Provision of
    an Educational Booklet for the Treatment of Patients with Low Back Pain

    New England Journal of Medicine 1998 (Oct 8); 339 (15): 1021-1029

  57. Balon, J, Aker, PD, Crowther, ER, Danielson, C, Cox, PG, O'Shaughnessy, D et al.
    Comparison of Active and Simulated Chiropractic Manipulation as Adjunctive
    Treatment for Childhood Asthma

    New England Journal of Medicine 1998 (Oct 8); 339 (15): 1013-1020

  58. Browning, R, Jackson, JL, and O'Malley, PG.
    Cyclobenzaprine and back pain: a meta-analysis.
    Arch Intern Med. 2001; 161: 1613–1620

  59. Dopf, CA, Mandel, SS, Geiger, DF, and Mayer, PJ.
    Analysis of spine motion variability using a computerized goniometer compared to physical examination. A prospective clinical study.
    Spine. 1995; 19: 586–589

  60. Miller, SA, Mayer, T, Cox, R, and Gatchel, RJ.
    Reliability problems associated with the modified Schober technique for true lumbar flexion measurement.
    Spine. 1992; 17: 345–348

  61. Williams, R, Binkley, J, Bloch, R, Goldsmith, CH, and Minuk, T.
    Reliability of the modified Schober and double inclinometer methods for measuring lumbar flexion and extension.
    Phys Ther. 1993; 73: 33–44

  62. Eisenberg DM, Davis RB, Ettner SL, Appel S, Wilkey S, Van Rompay M, Kessler RC.
    Trends in Alternative Medicine Use in the United States, 1990 to 1997:
    Results of a Follow-up National Survey

    JAMA 1998 (Nov 11); 280 (18): 1569–1575

  63. Eisenberg, DM, Kessler, RC, Foster, C, Norlock, FE, Calkins, DR, and Delbanco, TL.
    Unconventional Medicine in the United States: Prevalence, Costs, and Patterns of Use
    New England Journal of Medicine 1993 (Jan 28); 328 (4): 246–252

  64. Morin, CM, Colecchi, C, Brink, D, Astruc, M, Mercer, J, and Remsberg, S.
    How “blind” are double-blind placebo-controlled trials of benzodiazepine hypnotics?.
    Sleep. 1995; 18: 240–245

  65. van Tulder, MW, Koes, BW, and Bouter, LM.
    Conservative treatment of acute and chronic nonspecific low back pain: a systematic review of randomized controlled trials of the most common interventions.
    Spine. 1997; 22: 2121–2156






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