J Manipulative Physiol Ther. 2000 (Oct); 23 (8): 536544 ~ FULL TEXT
Gert Bronfort, DC, PhD, Roni L. Evans, DC, Alfred V. Anderson, MD,
Kurt P. Schellhas, MD, Timothy A. Garvey, MD, Ruth Ann Marks, Sarah Bittell, DC
Wolfe-Harris Center for Clinical Studies,
Northwestern Health Sciences University,
Bloomington, MN 55431, USA.
OBJECTIVES: To assess the feasibility of patient recruitment, the ability of patients and clinicians to comply with study protocols, and the use of data collection instruments to collect cost-effectiveness data, and to obtain variability estimates for sample-size calculations for a full-scale trial.
STUDY DESIGN: Prospective, observer-blinded, pilot randomized clinical trial.
SETTING: Primary contact chiropractic and medical clinics.
PATIENTS: Ages 20 to 65 years, with low back-related radiating leg pain (sciatica).
OUTCOME MEASURES: Self-report questionnaires were administered at baseline and 3 and 12 weeks after randomization. The measures included leg and back pain severity, frequency and bothersomeness of symptoms, leg/back disability, medication use, global improvement, satisfaction, and health care utilization.
INTERVENTIONS: Medical care, chiropractic care, and epidural steroid injections.
RESULTS: A total of 706 persons were screened by phone to determine initial eligibility. Of these, over 90% of those persons contacted did not meet the entrance criteria. The most common reason for disqualification was that the duration of the complaint was longer than 3 months. Twenty patients were randomized into the study. All 3 groups showed substantial improvements in the main patient-rated outcomes at the end of the 12-week intervention phase. For leg pain, back pain, frequency and bothersomeness of leg symptoms, and Roland-Morris disability score, the percent improvement varied from 50% to 84%, and the corresponding effect sizes ranged from 0.8 to 2.2. Bothersomeness of leg symptoms was the most responsive outcome associated with the largest magnitude of effect size. All within-group changes from baseline were statistically significant (P <.01). No between-group comparisons were planned or performed because of the insufficient sample size and high risk of committing type I and type II errors.
CONCLUSIONS: Pilot studies such as these are important for the determination of the feasibility of conducting costly, larger scale trials. Recruitment for a full-scale study of sciatica of 2 to 12 weeks duration is not feasible, given the methods used in this pilot study. Our results do indicate, however, that there are substantial numbers of patients with sciatica more chronic in nature who would be interested in participating in a similar study. In addition, collaboration with a local health maintenance organization would likely facilitate clinician referrals and optimize the recruitment process. Patient and provider compliance was high in the pilot study, which indicates that most study protocols are feasible. Additionally, we were able to collect complete outcomes data, including those regarding health care use. A suggested modification by investigators and outside consultants has resulted in the replacement of the medication group with a minimal intervention control group (ie, self-care advice). As a result, a second pilot study of patients with sciatica of more than 4 weeks duration has been planned before a full-scale trial is attempted.
From the FULL TEXT Article:
Low back pain (LBP) is one of the most common and costly problems facing the United States health-care system. [1-3] Back-related leg pain or sciatica is one of the common variations of LBP, with a lifetime incidence estimated between 2% and 40%. [4-6]Among patients with LBP, 12% have accompanying leg symptoms. [7, 8] Sciatica is often a disabling condition, accounting for greater work loss than uncomplicated LBP.  Although most first-time LBPs and sciatica resolve spontaneously, recurrences of nontreated lumbar and radicular pain range from 40% to 80% and are more likely to occur in patients with sciatica. [10, 11]
Sciatica can be defined as back-related lower extremity symptoms that suggest lower lumbar nerve root irritation. Sciatica symptoms are typically characterized by pain, numbness, and/or burning in the sciatic nerve distribution. A common cause of sciatica is nerve root compromise as the result of lower lumbar disk herniation, which leads to compression or traction and subsequent intraneural inflammation. [12-14] This inflammation may also be caused by biochemical mechanisms. Breakdown products from degenerating nucleus pulposis tissue of the disk may leak into the epidural space and result in chemical radiculitis of the nerve root.  Other possible causes are spinal stenosis, vertebral foraminal narrowing, and synovial cysts. Rare causes include spinal and retroperitoneal tumors.  The lifetime incidence of low back surgeries in the United States is 1% to 2%.  However, in patients with severe sciatica pain, this lifetime incidence increases to 10%.  Conservative or nonoperative management is commonly recommended for most patients with sciatica. This includes oral and injected medications and physical treatments such as spinal manipulation. [18, 19]
Several retrospective and prospective case series studies of spinal manipulative therapy (SMT) for sciatica or disk herniation have been performed, almost all of which have reported favorable outcomes. [20-27] However, there are relatively few randomized clinical trials that have specifically studied patients with sciatica. In a large, hospital-based trial by Mathews et al,  significantly more patients in the SMT group had experienced recovery at 2 weeks when compared with the group that received heat alone. Coxhead et al,  who evaluated 16 combinations of conservative therapies, found a statistically significant advantage in pain reduction for the groups that received SMT compared with the non-SMT groups. In the study by Nwuga,  significant improvement in spinal flexion and straight leg raise occurred in the group that received SMT versus the group that received short-wave diathermy and low-intensity exercise. Contrastingly, the study by Siehl et al  found that patients who received SMT showed less change in clinical improvement than patients who underwent disk surgery.
Although overall, these studies suggest that SMT is a promising therapeutic approach for sciatica, they have been cited as having relatively poor methodologic quality. [32-34] Additionally, 3 systematic reviews [35-37] conclude that there is currently no conclusive evidence for or against the efficacy of SMT for this condition.
Two separate clinical guidelines and a recent systematic review have concluded that there is evidence to support the use of nonsteroidal anti-inflammatory drugs (NSAIDs) for acute low back, which may include leg pain. [33, 38, 39] Another systematic review performed by Koes et al  found that NSAIDs might be effective for short-term relief for uncomplicated LBP but are less effective or ineffective in patients with sciatica or nerve root symptoms. However, like many of the trials for SMT, the methodologic quality of most medication trials is generally low. 
Epidural corticosteroid injections are also commonly used in the management of sciatica. [41, 42] In the recent Maine lumbar spine study, an estimated 18% to 20% of patients with sciatica received this therapy during the observation period.  Despite its popularity, there is still uncertainty regarding the efficacy of this procedure. One meta-analysis  concluded that epidural steroid injections are effective in the treatment of sciatica both in the short and long term. However, authors of 3 other systematic reviews [33, 45, 46] concluded that the results of the research performed to date are inconsistent and that the effectiveness of epidural steroid injections for sciatica has not yet been established. Also, there is uncertainty about which types of patients with sciatica may benefit. Given these concerns, further research evaluation of epidural injections is definitely warranted.
Efforts to enhance patient responsibility, to decrease costs, and to improve quality of care have lead to the increased use of self-care education in the treatment of LBP disorders.  An example of this is back education materials, which have been advocated by recent evidence-based clinical guidelines for LBP and sciatica in the United States and the United Kingdom. [18, 49]
The purpose of this pilot study was to evaluate the feasibility of conducting a randomized clinical trial to examine the effectiveness of 3 common treatment approaches for sciatica: medical care, chiropractic care, and epidural steroid injections, all with self-care education. The specific aims of the pilot study were to assess the feasibility of patient recruitment, the ability of patients and clinicians to comply with study protocols, and the utility of data collection instruments to capture cost-effectiveness data. A final goal was to obtain variability estimates for sample-size calculations for a full-scale trial.
Despite their common use, there is a paucity of well-designed research that evaluates spinal manipulation, medication, and epidural steroid injections for patients with sciatica. The current project was an initial step in remedying this problem. A pilot study was conducted to assess the feasibility of conducting a randomized study that would evaluate these 3 treatments for sciatica.
Feasibility of patient recruitment
We have determined that recruitment for our target population of subacute patients with sciatica (duration, 2-12 weeks) will not be feasible for a full-scale study. Even though an aggressive media campaign was undertaken, we recruited fewer than 2 patients per month. There are a few issues that may explain this. First, we were unable to access patients with sciatica when they initially entered into the health care system. Our collaborating physicians had patients with sciatica who were referred from other clinicians, for whom conservative treatments were not recommended. Thus, to access patients who may be eligible for conservative therapies we need to identify them as they first enter into the health care system. Ideally, collaboration with a local health maintenance organization would allow for the most referrals. However, in the current health care climate, recruitment of fee-for-service patients to participate in research will be challenging even in the best of circumstances. Second, our inability to recruit patients may be that the prevalence of sciatica is overestimated. Finally, it appears as if our inclusion/exclusion criteria were too restrictive. This is illustrated by the substantial number of individuals with sciatica of longer duration (more than 12 weeks) who expressed interest in the study. The fact that we identified many individuals with chronic sciatica who were interested in participating in this study suggests that a future trial that would include this population of patients is warranted. However, just because so many individuals expressed interest in participating does not mean that they would have qualified for such a study. Thus, another pilot study (with expanded inclusion criteria) is required to determine the true feasibility of recruiting sufficient patients for a large-scale study of patients with sciatica of longer duration.
Overall, patients and clinicians were willing and able to comply with the study protocols. Some difficulties were encountered with the scheduling of the self-care appointments, but this was attributable to a restrictive schedule on the part of the clinician and can be remedied easily for a full-scale trial. There was also a feeling that the protocol for the medical care group was too restrictive. Because of individual patient tolerances, we anticipate that a broader spectrum of prescription medications is required to optimally treat patients in the medication group. Although a medication group is important to study, the range of different medications creates a relatively diffuse treatment group (eg, mixture of NSAIDs, mild-narcotics). In comparison, the spinal manipulation and epidural steroid injections are more well-defined interventions and can be consistently applied across patients. For studies that assess relative treatment effectiveness, this is preferable. Given this and consultants' recommendations, we believe it would be prudent to replace the medication group with a minimal intervention control group. Minimal interventions such as self-care education have been used as control devices in previous clinical trials, including studies on spinal manipulation. [71, 72] The advantage of such a minimal intervention control is that it may enhance patient compliance in clinical trials, in which patients expect some sort of treatment (in contrast with a waiting list or no treatment) and that it provides an interesting comparison in terms of cost-effectiveness.
Additionally, patients in all 3 groups of the proposed study could, according to a prespecified protocol, be prescribed medication if their symptoms could not be managed solely by their randomly assigned treatment (spinal manipulation, epidural steroid injections, or self-care). The need for such rescue medication would then be documented and taken into account in the statistical analyses. Whether patients with sciatica would comply with these adjusted protocols remains to be seen and needs to be evaluated in a subsequent pilot study.
Data collection instruments
The data collection instruments in the current pilot study performed well, with minimal missing data. Completed data collection forms that captured treatment visits and procedures were received in a timely fashion from all study providers, which indicates that this is a satisfactory method for capturing this type of data.
The final goal of the current study was to generate variability estimates for sample-size calculations for a full-scale study. The sample in the current study was limited, however, to patients who experienced sciatica for 2 to 12 weeks. It is likely that the variability of outcomes in patients with sciatica of more than 12 weeks duration will be somewhat different than those gathered in this study. Thus, for more accurate sample-size calculations, variability estimates should be gathered in a pilot study of the intended full-scale trial population, most of who will have sciatica for more than 12 weeks.
It is not known whether patients with low-back-related radiating pain into the lower extremity (sciatica) will respond differently to conservative management that is based on the presence or absence of neurologic signs of nerve root irritation. In our experience, patients in QTF category 2 and 3 (absence of objective signs of radiculopathy) often have pain of neurogenic character, and the source of the pain cannot be determined with any degree of certainty. These patients do, however, frequently experience a positive response to either spinal manipulation or epidural injections.
For a full-scale trial, patients could be prestratified at randomization, according to the absence or presence of lumbar radiculopathy (based on objective neurologic findings). In the current pilot study of patients with subacute sciatica, 30% of the 20 patients had lumbar radiculopathy. The extension of this pilot study, with the inclusion of patients with chronic sciatica, would allow us to determine the feasibility of recruiting sufficient numbers of patients for a full-scale trial with enough statistical power to perform separate analyses for both subgroups (patients with and without radiculopathy). Currently, our estimated sample size for a full-scale trial is 83 patients per group. If we assume that 30% of the patients in our planned full-scale trial will have lumbar radiculopathy, we would have an estimated 25 patients with radiculopathy in each group. Our plan is to use the most responsive of the relevant outcome measures for the subgroup analyses at the end the 12 weeks of intervention. In this pilot study, the most responsive measure was bothersomeness of back and leg symptoms, with a mean reduction of symptoms corresponding to an effect size of 2.2. On the basis of this outcome measure and its variability, 25 patients in each group would allow us to detect a difference of one half of a point on the 0 to 5 scale, which would correspond to a large effect size difference, with a statistical power of 0.8 tested at an alpha level of 0.05 (2-tailed test). This was the approximate magnitude of group differences seen in our pilot study. If it is not feasible to recruit a sufficient number of patients with radiculopathy to ensure reasonable power, our planned full-scale trial would still be balanced between groups on the presence or absence of radiculopathy, and we will have obtained valuable descriptive outcomes data to influence the conduct of a future study.
Pilot studies such as these are important for determining the feasibility of conducting costly, larger scale trials. They also provide the opportunity to refine study protocols and to gain more accurate variability estimates on which to base sample-size calculations. On the basis of the results of this pilot study, we conclude that recruitment for a full-scale study of sciatica of 2 to 12 weeks duration is not feasible, given the methods used. Our results do indicate, however, that there are substantial numbers of patients with sciatica more chronic in nature who would be interested in participating in a similar study. In addition, collaboration with a local health maintenance organization would likely facilitate clinician referrals and optimize the recruitment process. Patient and provider compliance was high in the pilot study, which indicated that most of the study protocols are feasible. Additionally, we were able to collect complete outcomes data, including those regarding health care use. Investigators and consultants have recommended that the medication group be replaced with a minimal intervention control group (ie, self-care advice). As a result, a second pilot study of patients with sciatica of more than 4 weeks duration has been planned before proceeding to a full-scale trial. The second pilot study will randomly assign patients to chiropractic care, injections, or self-care advice and will assess the feasibility of recruiting and retaining sufficient numbers of patients with chronic sciatica. It will also provide variability estimates for the chosen main outcome measures in patients with sciatica of longer duration.
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