J Manipulative Physiol Ther. 2004 (Oct); 27 (8): 503508 ~ FULL TEXT
Gert Bronfort, DC, PhD, Roni L. Evans, DC, Michele Maiers, DC, Alfred V. Anderson, MD
Wolfe-Harris Center for Clinical Studies,
Northwestern Health Sciences University,
Bloomington, MN 55431, USA.
OBJECTIVE: To assess the feasibility of recruiting sciatica patients and to evaluate their compliance in preparation for a full-scale randomized clinical trial. We also aimed to determine the responsiveness of key outcome measures.
METHODS: Thirty-two subjects were randomly assigned to spinal manipulation (n=11), epidural steroid injections (n=11), or self-care education (n=10). No between-group comparisons were planned because of the small sample size.
RESULTS: At week 12 (the end of the treatment phase), the outcome measures indicating the most improvement/change were the Oswestry disability score (mean, 22.9; SD, 19.9; effect size [ES], 1.8), leg pain severity (mean, 2.9; SD, 1.7; ES, 1.7), and if the symptoms were bothersome (mean, 25.2; SD, 16.0; ES, 1.6). Twenty-four patients were either "very satisfied" or "completely satisfied," and 22 of 32 patients reported 75% or 100% improvement. After 52 weeks, the outcome measure showing the most improvement/change was leg pain severity (mean, 2.3; SD, 2.6; ES, 1.35), followed by the Oswestry disability score (mean, 15.6; SD, 20; ES, 1.2) and if symptoms were bothersome (mean, 18.1; SD, 22.6; ES, 1.1). Eighteen patients were either "very satisfied" or "completely satisfied," and 15 of 32 patients reported 75% or 100% improvement.
CONCLUSIONS: The results of this pilot study suggest that it is feasible to recruit subacute and chronic sciatica patients and to obtain their compliance for a full-scale randomized clinical.
Keywords Chiropractic Manipulation, Drug Therapy, Spine, Sciatica
From the FULL TEXT Article:
Back-related leg pain, or sciatica, is one of the common variations of low-back pain. [1, 2] Sciatica sufferers have been identified as an important subgroup of low-back pain patients with potentially different prognoses and responses to treatment. [3, 4] Often disabling, sciatica accounts for more work loss than uncomplicated low-back pain  and is associated with more recurrences and an increased need for surgery. 
Sciatica is commonly equated with lumbar radiculopathy caused by mechanical root compression secondary to a disk herniation. However, there is a substantial amount of research indicating that radiating pain to the leg often exists in the absence of disk herniation. Discography studies have shown that internal disruption associated with annular tears in the posterior part of the disk, when provoked by irritating dye injections, can reproduce pain radiation into the lower limb.  These leg symptoms thus occur in the absence of direct nerve compression or irritation by a disk fragment in the epidural space. It has also been shown that breakdown products from degenerating nucleus pulposus tissue may leak into the epidural space and result in inflammatory changes involving the nerve root. [8, 9]
Surgery is a costly treatment strategy for sciatica and is only indicated for patients with progressive neurologic deficits or unmanageable pain. Nonsurgical treatment such as spinal manipulation, epidural steroid injections, and self-care advice are prescribed for many sciatica patients.  Despite their common use, however, there is still uncertainty regarding the efficacy of these interventions and a need for randomized clinical studies. 
The purposes of this pilot study were to assess the feasibility of recruiting patients, to evaluate their compliance in preparation for a full-scale randomized clinical trial, and to determine the responsiveness of key outcomes. A previous pilot study with more restrictive inclusion and exclusion criteria indicated recruitment of acute and subacute sciatica patients would not be possible in our setting.  However, through the first pilot study, we identified a broader population of patients who had suffered with sciatica for longer periods of time. Subsequent design changes, specifically the addition of a self-care education group, also required further testing. Would patients with chronic sciatica be willing to accept a minimal intervention such as self-care education? Furthermore, could chronic sciatica patients comply with the proposed study protocols including questionnaires, objective testing, and random assignment to 1 of 3 treatments? Finally, given the limited available scientific literature regarding sciatica of longer duration, it was necessary to assess the performance of our outcome measures and obtain variability estimates for new sample size calculations.
One of the most critical aspects of conducting a randomized clinical trial is the ability to recruit qualified and willing participants. In our previous pilot study of acute and subacute sciatica patients, the recruitment rate during a 1year period was less than 3% (20 individuals randomized of 706 individuals initially screened by telephone). Consequently, we determined that recruitment for a full-scale study was not feasible in our setting. However, we did identify a substantial number of chronic sciatica sufferers seeking relief, which led to this second pilot study. The recruitment rate for the current study was approximately 10% (32 randomized of 344 initially screened), which was more than 3 times what was observed in the first pilot study. Further, this recruitment rate is likely an underestimation due to the fact that 56 patients had to be wait-listed because the study became full.
Although our recruitment efforts for the second pilot study were successful, we also identified barriers to recruitment for future full-scale trials. Almost a one-third (101 of 344) of those interviewed were not interested in participating in this study. The most common reason given for declining participation was not wanting to accept the chance of receiving epidural steroid injections (26 of 101). Thus, future recruitment efforts will need to take into account the general public's preconceived opinions regarding the study therapies and perhaps adopt a more educational approach.
Patient compliance with the treatment and data collection protocols in this study was high, with only 1 of 32 patients refusing treatment (injection group) and 31 of 32 patients completing the week 12 evaluations. Data were also successfully collected 1 year after treatment, with 28 of 32 randomized patients returning the mailed self-report questionnaires. A concern in this study was whether chronic sciatica patients would perceive the self-care education group as a legitimate treatment approach. Nine of 32 study patients expected they would experience no change with self-care, compared with 3 patients expecting no change with chiropractic treatment and 0 patients expecting no change with injections. However, those that received the self-care treatment seemed to tolerate it well, with all patients randomized to that group completing the treatment and follow-up visits. Furthermore, more than half the patients in the self-care group were highly satisfied with the care they received and half of them reported 50% to 100% improvement 12 weeks after treatment and 1 year later. These results suggest that the self-care education group is a feasible minimal intervention group for randomized clinical trials assessing patients with subacute and chronic sciatica. However, because of expectation differences and their potential effect on outcomes, pretreatment expectations should be measured and factored into the statistical analyses.
The Oswestry Disability Questionnaire, leg pain, and how bothersome symptoms were were the most responsive outcome measures in this sample of subacute and chronic sciatica patients. These were also the most responsive outcomes in the previous pilot study of acute and subacute sciatica sufferers,14 although the magnitude of effect sizes was somewhat larger in the previous study. This may be related to the chronicity of sciatica experienced by individuals in the current study, who may be more prone to smaller degrees of improvement, which is then reflected in the outcome measures. Future studies of chronic sciatica patients may want to consider the use of questionnaires that measure coping and fear avoidance behaviors to reflect some of the other dimensions of the chronic pain experience.
The costs associated with this second pilot study were substantial in terms of financial resources, effort, and time. High-quality clinical research is an arduous and costly process with few quick answers. To proceed with a full-scale randomized clinical trial without critical information regarding recruitment feasibility and study protocols raises the potential for squandered finances, immense frustration, and wasted effort on the part of patients and personnel should the study be unsuccessful. Two recent pilot studies [14, 24] have successfully shown the usefulness of pilot studies to identify areas in which the subsequent full-scale randomized trials would have failed. Although patients, clinicians, and health care policy makers clamor for scientific evidence now, investigators and funding agencies have a responsibility to ensure that the appropriate steps are taken to ensure the successful conduct and completion of high-quality clinical research. This includes establishing the feasibility and likelihood of success through well-designed pilot studies.
The results of this pilot study suggest that it is feasible to recruit subacute and chronic sciatica patients for a randomized clinical trial to compare chiropractic care, epidural steroid injections, and self-care education. Furthermore, subacute and chronic sciatica patients appear willing and able to comply to with the study protocols, as described in this article. Appropriate outcome measures have been identified, and variability estimates have been obtained to inform the sample size of future full-scale trials. Although this second pilot study required substantial time and resources, the lessons learned and conclusions drawn are valuable for the successful conduct of future research.
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