Long-term Follow-up of a Randomized Clinical Trial Assessing
the Efficacy of Medication, Acupuncture, and Spinal Manipulation
for Chronic Mechanical Spinal Pain Syndromes

This section was compiled by Frank M. Painter, D.C.
Send all comments or additions to:    Frankp@chiro.org

FROM:   J Manipulative Physiol Ther 2005 (Jan); 28 (1): 3–11 ~ FULL TEXT

Reinhold Muller, PhD, Lynton G.F. Giles, DC, PhD

Lynton G.F. Giles, DC, PhD,
PO Box 880, Indooroopilly,
Queensland 4068, Australia

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This study conducted a one-year follow-up of a randomized clinical trial investigating the effectiveness of medication (Celebrex, Vioxx and/or acetaminophen), acupuncture or high-velocity low-amplitude spinal manipulation on treating chronic spinal pain. Sixty-nine patients were randomized into three treatment groups, receiving one type of treatment for nine weeks. The one-year follow-up was conducted through Oswestry Back Pain Index, Neck Disability Index, Short-Form-36 and Visual Analog Scales. The study analyzed the results of treatment of 40 patients who had received only one randomly allocated type of treatment. RESULTS Comparison of the initial and long-term follow-up questionnaires produced the following results: Only the group receiving spinal manipulation showed long-term treatment benefit, with five of the original seven improvements remaining statistically significant after one year. Only one of seven improvements remained statistically significant in each of the acupuncture and the medication treatment groups at follow-up.

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OBJECTIVE:   To assess the long-term benefits of medication, needle acupuncture, and spinal manipulation as exclusive and standardized treatment regimens in patients with chronic (>13 weeks) spinal pain syndromes.

STUDY DESIGN:   Extended follow-up (>1 year) of a randomized clinical trial was conducted at the multidisciplinary spinal pain unit of Townsville's General Hospital between February 1999 and October 2001.

PATIENTS AND METHODS:   Of the 115 patients originally randomized, 69 had exclusively been treated with the randomly allocated treatment during the 9-week treatment period (results at 9 weeks were reported earlier). These patients were followed up and assessed again 1 year after inception into the study reapplying the same instruments (ie, Oswestry Back Pain Index, Neck Disability Index, Short-Form-36, and Visual Analogue Scales). Questionnaires were obtained from 62 patients reflecting a retention proportion of 90%. The main analysis was restricted to 40 patients who had received exclusively the randomly allocated treatment for the whole observation period since randomization.

RESULTS:   Comparisons of initial and extended follow-up questionnaires to assess absolute efficacy showed that only the application of spinal manipulation revealed broad-based long-term benefit: 5 of the 7 main outcome measures showed significant improvements compared with only 1 item in each of the acupuncture and the medication groups.

CONCLUSIONS:   In patients with chronic spinal pain syndromes, spinal manipulation, if not contraindicated, may be the only treatment modality of the assessed regimens that provides broad and significant long-term benefit.

The results of this “fastidious” approach were able to add some information regarding the efficacy of treatment regimens in patients with chronic spinal pain syndromes. Overall, patients who have chronic mechanical spinal pain syndromes and received spinal manipulation gained significant broad-based beneficial short-term and long-term outcomes. For patients receiving acupuncture, consistent improvements were also observed, although without reaching statistical significance (with a single exception). For patients receiving medication, the findings were less favorable. Larger studies are now clearly justified.

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From the Full-Text Article:

Introduction

Chronic spinal pain is commonly triggered by an injury or disease, [1] and mechanical spinal pain presents a diagnostic and treatment challenge because reaching a specific diagnosis is often impossible. [2] A pathological cause cannot be identified for most episodes of spinal pain [3] with only approximately 15% of patients being given a definitive diagnosis. [4]

The search for effective conservative treatments for acute and chronic nonspecific low-back pain has been largely inconclusive, [5, 6] as is the case with neck and thoracic spine pain. Conflicting claims exist for nearly every form of conservative therapy for low-back disorders, probably because studies have been performed among widely differing types of patients with back pain or because of methodological problems. [7] Thus, there is still sparse conclusive knowledge about the absolute efficacy of any intervention for chronic spinal pain syndromes, although Giles et al [8] found a high level of patient satisfaction with a multidisciplinary team approach to spinal pain syndromes. A review of the conflicting literature on the efficacy and effectiveness of medication, acupuncture, and spinal manipulation for chronic uncomplicated spinal pain treatment can be found in Giles and Muller. [9]

What is not disputed is that chronic spinal (ie, neck and “back”) pain syndromes have an immense impact on public health, pose an enormous financial strain on the health systems in developed countries, and affect the economy by lost working time through illness. The high incidence of back pain, its chronic and recurrent nature in many patients, and its contribution as a main cause of absence from work are well known. [10] Furthermore, the rise in the use of nontraditional health care providers partly reflects the large number of patients with chronic pain, especially spine-related disorders, who feel they must go outside mainstream medicine to find help. [11]

The immense burden of chronic spinal pain syndromes, in terms of suffering as well as in financial terms, stands in stark contrast to the paucity of evidence-based knowledge about their diagnosis and treatment. It is against this background that the Giles and Muller [9] randomized clinical trial was designed with a rigorous protocol and a broad range of outcome measures in an attempt to overcome the abovementioned methodological problems and to add much-needed evidence-based knowledge to this important area.

In their 109-patient randomized clinical trial, Giles and Muller [9] included both neck and “back” (ie, low back and thoracic spine) pain patients as it would have been unethical to treat only 1 painful spinal level and to ignore a concurrent additional painful spinal level, particularly when 47 (68%) of 69 patients presented with pain at more than 1 spinal level.

Giles and Muller, [12] using a “fastidious” [10] approach (ie, standardized treatment regimens of medication, needle acupuncture, or spinal manipulation with respect to the type, frequency, and duration of each treatment regimen), showed in a public hospital-based multidisciplinary spinal pain unit pilot study and in the subsequent larger study [9] that in patients with chronic (ie, >13 weeks' duration) spinal pain, spinal manipulation, if not contraindicated, seems to result in greater short-term (9 weeks) improvement than acupuncture and medicine. There were no particular distinguishing features for pain other than pain of “mechanical” origin in all of the 3 spinal areas. In addition, there were no mechanisms of injury that were distinct enough to warrant separate investigation or management, and all patients were considered to have mechanical joint dysfunction after extensive investigations (ie, physical examination and various forms of imaging with or without laboratory tests as indicated by the history).

A thorough systematic review of the literature indicates that evidence-based knowledge (ie, originating from randomized clinical trials using standardized treatment regimens) about the short-term efficacy of different conservative treatment regimens for chronic spinal pain syndromes is scarce, and it is virtually nonexistent with respect to long-term benefit.

Very few long-term (ie, of at least 1-year follow-up) clinical trials of treatment(s) of patients with various spinal problems could be located for low-back pain [13-15] and chronic neck pain. [16] Moreover, these trials deliberately followed a pragmatic methodology (ie, details of the type, frequency, and duration of each treatment were at the discretion of the treating clinician) as opposed to a fastidious approach (ie, exclusively standardized treatment regimens) and consequently lacked the methodological scientific rigor necessary to be able to attribute an observed effect to only 1 specific standardized treatment modality.

The present study assesses the extended follow-up (of at least 1 year) efficacy of medication, needle acupuncture, and spinal manipulation, as standardized and exclusive treatment regimens. Patients with chronic spinal pain syndromes from the fastidious approach of the Giles and Muller [9] randomized clinical trial were eligible for this study if they adhered to the study protocol for their treatment period.

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Discussion

This is, to the authors' knowledge, the first report on long-term efficacy of 3 distinct and standardized treatment regimens for patients with chronic spinal pain syndromes using a “fastidious” approach; that is, the only type of study from which potentially valid inferences of cause and effect can directly be drawn. [24] The validity of the study (ie, the absence of different types of bias) is hereby essential and will be discussed first.

      Selection Bias

The study sample has a broad socioeconomic background and a wide age range. Quite stringent exclusion criteria guaranteed a pathologically homogeneous sample. It was successfully ascertained that all “dropouts” occurring during the study treatment period, as well as during the extended follow-up period thereafter, occurred for reasons unrelated to the study outcome (ie, moving overseas, being transferred, etc). A high retention proportion of 90% for this extended follow-up study, together with the above stated facts, supports the generalizability of the findings.

      Information Bias

Intention-to-treat analyses including noncompliers (1 for the 9-week treatment period [9] and 1 for the presented study) revealed results quite consistent with the respective compliers-only analyses thus effectively diminishing any relevant misclassification bias from noncompliers. A different color code was used from that in the 9-week analysis to ensure successful blinding [25] of data analysis. All data handling and analyses were again performed before the treatment color code was broken. The senior biostatistician was involved neither in the data collection process nor in any daily business of the center, thus minimizing information bias.

Blinding of the physician was not possible; even if, for instance, a “sham” acupuncture treatment would have been regarded as ethically justifiable, the acupuncturist would still have to know what treatment to perform. Blinding of the patients was not possible because there is, for instance, no known practical way to perform a sham manipulation. The potential for information bias, in this context, however, seems limited by the standardized treatment regimens and the fact that the clinician was not involved in measuring outcome. Information bias arising from a placebo effect or from a self-limiting effect is highly unlikely because patients in this study had chronic spinal pain syndromes (the average duration of having this exceeded 2 years) and had long histories of having sought pain relief. Improvement caused by the abovementioned effects could be expected in cases with acute spinal pain [26] but seems rather unlikely in long-term cases.

      Confounding Bias

Table 1 indicates that the 3 groups were very similar in their characteristics at inception. Additional bivariate and multivariate analyses of potential effects of these characteristics on the outcome measures also disproved any relevant confounding bias.

According to Turk and Rudy, [27] no clinical study can be completely valid because of the complexities of extended follow-up trials; however, we have attempted to conduct a well-executed extended follow-up randomized trial with a rigorous protocol, and the overall validity of the reported findings does not seem to be negatively affected by any obvious bias. The main emphasis of this study was to assess absolute efficacy; consequently, within-group comparisons constituted the basis for analysis. Additional across-group comparisons, as often used in clinical trials to assess relative efficacy (eg, when new treatments are compared with an accepted “gold” standard), would have resulted in 2-dimensional testing (ie, determining and validating a gold standard within the same data set) defying any meaningful interpretation. The validation process (ie, the relative comparison) consequently has to be reserved for future trials.

However, the presented trial with successful randomization, thorough concealment, and within-group analyses applied the most powerful design possible to a research area where no accepted gold standard exists and where the emphasis, at this early stage of the research process, has to be on absolute, as opposed to relative, efficacy.

It should be noted that definitions of chronicity for low-back pain have been suggested by various authors such as Nachemson and Bigos [28] and by Skouen et al. [29] For the reported study, the definition for chronic pain duration was more than 13 weeks, so it is against this definition that these results are to be interpreted.

The overall results of this extended follow-up efficacy study appear to favor the application of manipulation and suggest that manipulation, if not contraindicated, and, to some extent, also needle acupuncture seem to successfully achieve long-term benefits in chronic spinal pain syndrome patients. However, no such benefit could be observed for medication. These results not only corroborate the findings of the 9-week analysis [9] but also of the smaller pilot study. [12] It seems noteworthy that the comparison of the percentages of those who had to change the treatment modality (because of side effects or unsatisfactory results) also appears to favor manipulation in that manipulation showed by far the lowest proportion (38.7%) of changeovers compared with acupuncture (53.3%) and medication (81.2%). Consequently, spinal manipulation appeared to provide the highest satisfaction. Moreover, both the 9-week findings and the extended follow-up results are consistent with conclusions by Meade et al, [10, 13], who, on comparing chiropractic with hospital therapists for treating low-back pain as they would in day-to-day practice (“pragmatic” approach), reported that those treated by chiropractic derived more short-term and long-term benefit and satisfaction than those treated by hospital therapists.

Medication apparently did not achieve an improvement in chronic spinal pain, although the SF-36 indicator of general health status did show an improvement (P = .02) for general health status. This may reflect some satisfaction with not having the inconvenience of needing to attend twice weekly for treatment and/or may also suggest that medication did not act as a nocebo.

It is interesting that the application of manipulation and acupuncture seem roughly equally successful in the ITT analysis, but only manipulation seems of broad-based long-term benefit in the compliers-only analysis. A more detailed look at the noncompliers data revealed that 4 of the 6 patients in the acupuncture arm who had some other type of treatment than the randomly allocated regimen during the extended follow-up period were actually treated with manipulation. Therefore, an artificial inflation of the effect of acupuncture treatment in the ITT analysis by additional manipulation therapy seems likely. The compliers-only analysis therefore seems to provide information that is more accurate.

The ITT analysis, however, is per se relevant because it displays the information that would be available from a similar trial in a larger metropolitan setting where the information on additional treatment may not be collected (or at least only less reliably). The setting of the present trial in a small, geographically relatively isolated community which is served by only 1 major public (providing free treatment) hospital rendered it possible to directly collect precise information on possible additional treatments during the extended follow-up period by checking the single public hospital's computer records.

This advantage of the small community setting, however, is partly offset by a long inception period (several years) to reach the minimum necessary sample size. In this context, it seems noteworthy that because of the necessarily stringent inclusion and exclusion criteria, 533 patients had to be seen (and treated) at the unit to achieve the reported sample sizes, reflecting that only around 1 (22.3%) of 5 patients fulfilled the inclusion /exclusion criteria.

Another general reason for the relatively small sample sizes for the extended follow-up analysis, however, lies in the very nature of this strictly fastidious approach itself: the group of strict compliers necessarily dwindles with increasing period of observation as the likelihood increases that additional treatment (eg, simple pain killers) is used by those in the long-term condition. This consequence of the fastidious approach, however, is easily compensated for by the fact that it is the only approach where an observed effect can be unambiguously attributed to 1 specific treatment modality only (if the study follows an otherwise rigorous methodology). Moreover, it seems worth reiterating that statistical testing takes into account the sample size and the observed effects proved to be both medically relevant and statistically significant.

It should be emphasized that this study was exclusively concerned with chronic spinal pain, and therefore, no statement whatsoever can be made about the potential role of the investigated regimens in treating acute spinal pain syndromes.

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Conclusion

Chronic mechanical spinal pain syndromes are prevalent conditions [30] that tend to create a cluster of related problems reaching from withdrawal from social activity to a compromised immune function. [31] The associated resulting direct and indirect costs in industrialized communities are vast. [32] A large community study seems to be the next logical step to address this important problem and to further investigate the reported findings. Consideration should also be given to assessing the efficacy of other treatment modalities. This suggested study should be based on a fastidious approach and incorporate an expanded multidisciplinary team to gain further evidence-based information on the absolute and also the relative efficacy of all forms of available treatments.

The results of this “fastidious” approach were able to add some information regarding the efficacy of treatment regimens in patients with chronic spinal pain syndromes. Overall, patients who have chronic mechanical spinal pain syndromes and received spinal manipulation gained significant broad-based beneficial short-term and long-term outcomes. For patients receiving acupuncture, consistent improvements were also observed, although without reaching statistical significance (with a single exception). For patients receiving medication, the findings were less favorable. Larger studies are now clearly justified.

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