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Biomedical subjects

R B Keller

Publications and source records attributed to R B Keller.

At least 19 recordsLinked to original sources
PubMed2000

Surgical and nonsurgical management of lumbar spinal stenosis: four-year outcomes from the maine lumbar spine study.

STUDY DESIGN: A prospective cohort study of patients with lumbar spinal stenosis recruited from the practices of orthopedic surgeons and neurosurgeons throughout Maine. OBJECTIVE: To assess 4-year outcomes for patients with lumbar spinal stenosis treated surgically or nonsurgically. SUMMARY OF BACKGROUND DATA: Surgery for lumbar spinal stenosis has increased dramatically despite the lack of randomized trials comparing surgical with nonsurgical treatments. Long-term evaluation of surgical series has documented deterioration in initial symptomatic improvement, but few studies have compared long-term outcomes of surgical and nonsurgical treatment. METHODS: Eligible, consenting patients had baseline interviews with mailed follow-up questionnaires at 3, 6, and 12 months, then annually thereafter. Clinical data were obtained at baseline from a physician questionnaire. Outcomes included patient-reported symptoms of leg and back pain, functional status, and satisfaction. RESULTS: Of 148 patients with lumbar spinal stenosis initially enrolled, 4-year outcomes were available on 119 patients (80.4%): 67 of 81 (83%) treated surgically and 52 of 67 (78%) treated nonsurgically. The surgically treated patients had more severe symptoms and worse functional status at baseline and better outcomes at 4-year evaluation than the nonsurgically treated patients. After 4 years, 70% of the surgically treated and 52% of the nonsurgically treated patients reported that their predominant symptom, either leg or back pain, was better (P = 0.05). Satisfaction of patients with their current state at 4 years was reported by 63% of the surgically treated and 42% of the nonsurgically treated patients (P = 0.04). Surgical treatment remained a significant determinant of 4-year satisfaction, even after adjustment for other independent predictors (P = 0.001). For the nonsurgically treated patients, there was no significant change in outcomes over 4 years, whereas the initial improvement seen in the surgically treated patients modestly decreased over the subsequent 4 years. CONCLUSIONS: For the patients with severe lumbar spinal stenosis, surgical treatment was associated with greater improvement in patient-reported outcomes than nonsurgical treatment at 4-year evaluation, even after adjustment for differences in baseline characteristics among treatment groups. The relative benefit of surgery declined over time but remained superior to nonsurgical treatment. Outcomes for the nonsurgically treated patients improved modestly and remained stable over 4 years. Determining whether outcomes continue to converge will require longer-term evaluation.

Activities of Daily Living↗
PubMed2000

Long-term disability and return to work among patients who have a herniated lumbar disc: the effect of disability compensation.

BACKGROUND: Low-back problems are one of the most frequent reasons for disability compensation claims by workers. However, the effect of Workers' Compensation status on the long-term outcome for workers with sciatica has not been studied in detail, to our knowledge. Therefore, we believe that it is important to describe the long-term outcomes for patients who have herniation of a lumbar disc and sciatica according to the Workers' Compensation status at the time of the preoperative consultation. METHODS: We conducted a prospective, observational study of patients who had sciatica and were seeking care from specialist physicians in community-based practices throughout Maine. Among 440 eligible patients, 199 were receiving Workers' Compensation at the time of entry into the study (baseline) and 241 were not. Three hundred and twenty-six patients (74 percent) completed questionnaires at the time of a four-year follow-up. The outcomes that we assessed included disability compensation and work status as well as relief from symptoms, functional status, and quality of life. RESULTS: Patients who were receiving Workers' Compensation at baseline were more likely to be young, male, and employed as laborers. They reported worse functional status; however, the clinical findings for these patients were similar to those for patients who were not receiving Workers' Compensation. Patients who had been receiving Workers' Compensation at baseline were more likely to be receiving disability benefits at the time of the four-year follow-up compared with those who had not (27 percent of 133 compared with 7 percent of 189; p<0.001); however, they were only slightly less likely to be working at the time of the four-year follow-up (80 percent of 133 compared with 87 percent of 190; p = 0.09). Operative management did not influence these comparisons, but it decreased symptoms and improved functional status. Patients who had been receiving Workers' Compensation at baseline also had significantly less relief from symptoms and improvement in quality of life than patients who had not been receiving Workers' Compensation (all p<0.001). In multivariate models, Workers' Compensation status at baseline was an independent predictor of whether the patient would be receiving disability benefits after four years (odds ratio, 3.5; 95 percent confidence interval, 1.7 to 7.6) but was not an independent predictor of whether the patient would be working on a job for pay at the time of the four-year follow-up (odds ratio, 0.6; 95 percent confidence interval, 0.3 to 1.2). CONCLUSIONS: Even after adjustment for the initial treatment of the sciatica and for other clinical factors, patients who had been receiving Workers' Compensation at baseline were more likely to be receiving disability benefits and were less likely to report relief from symptoms and improvement in quality of life at the time of the four-year follow-up than patients who had not been receiving Workers' Compensation at baseline. Nonetheless, most patients returned to work regardless of their initial disability status, and those who had been receiving Workers' Compensation at baseline were only slightly less likely to be working after four years. Whether or not they had been receiving Workers' Compensation at baseline, patients who had been managed with an operation reported greater relief from symptoms and improvement in functional status at the time of the four-year follow-up compared with patients who had been managed nonoperatively, even though the outcomes with regard to disability and work status in these two groups were comparable.

Adult↗
PubMed1999

The relation between expectations and outcomes in surgery for sciatica.

OBJECTIVE: To describe the expectations that patients and their physicians have for outcomes after surgical treatment for sciatica and to examine the associations between expectations and outcomes. DESIGN: Prospective cohort study. SETTING/PATIENTS: We recruited 273 patients, from the offices of orthopedic surgeons, neurosurgeons, and occupational medicine physicians in Maine, who had diskectomy for sciatica. MEASUREMENTS AND MAIN RESULTS: Patients' and physicians' expectations were measured before surgery. Satisfaction with care and changes in symptoms and functional status were measured 12 months after surgery. More patients who expected a shorter recovery tJgie after surgery were "delighted," "pleased," or "mostly satisfied" with their outcomes 12 months after surgery than patients who expected a longer recovery tJgie (odds ratio [OR] 2.2; 95% confidence interval [CI] 1.1, 4.4). Also, more patients who preferred surgery after learning that sciatica could get better without surgery had good symptom scores 12 months after surgery than patients who did not prefer surgery (OR 2.9; 95% CI 1.2, 7.0). When physicians predicted a "great deal of Jgiprovement" after surgery, 39% of patients were not satisfied with their outcomes and 25% said their symptoms had not Jgiproved. CONCLUSIONS: More patients with favorable expectations about surgery had good outcomes than patients with unfavorable expectations. Physicians' expectations were overly optJgiistic. Patient expectations appear to be Jgiportant predictors of outcomes, and eliciting them may help physicians identify patients more likely to benefit from diskectomy for sciatica.

Adult↗
PubMed1999

Relationship between rates and outcomes of operative treatment for lumbar disc herniation and spinal stenosis.

BACKGROUND: Population-based variations in rates of operations for the treatment of lumbar disc herniation and spinal stenosis are well known. This variability may occur in part because of differences in the threshold at which physicians recommend an operation, reflecting uncertainty about the optimum use of an operative procedure. To the best of our knowledge, no previous reports have indicated whether differences in population-based rates of operative treatment are associated with patient outcomes. METHODS: The Maine Lumbar Spine Study is an ongoing prospective study of 655 patients who had a herniated lumbar disc or spinal stenosis. The patients were enrolled by their physicians, who provided baseline demographic and treatment-related data. The patients completed baseline and follow-up questionnaires that focused on symptoms, function, satisfaction, and quality of life. Small-area variation analysis was used to develop three distinct so-called spine service areas in Maine. The outcomes (usually at four years; minimum, two years) were compared among these areas, in which a total of 250 patients had been managed operatively and had answered questionnaires. RESULTS: Population-based rates of operative treatment derived from statewide data that had been collected over five years in the state of Maine ranged from 38 percent below to 72 percent above the average rate in the state (a greater than fourfold difference). The outcomes for the patients who had been managed by surgeons in the lowest-rate area were superior to those for the patients in the two higher-rate areas. Seventy-nine percent (fifty-seven) of seventy-two patients in the lowest-rate area had marked or complete relief of pain in the lower extremity compared with 60 percent (eighteen) of thirty patients in the highest-rate area. The improvements in the Roland disability score (p < or = 0.01), quality of life (p < or = 0.01), and satisfaction (p < or = 0.05) were significantly greater among the patients in the lowest-rate area. The patients in the higher-rate areas generally had less severe symptoms and findings at baseline than those in the lowest-rate area did. CONCLUSIONS: Higher population-based rates of elective spinal operations may be associated with inferior outcomes. This variability is possibly related to differences in physicians' preferences with regard to recommending an operation and in their criteria for the selection of patients. Physicians cannot assume that their outcomes will be the same as those of others, and therefore they need to evaluate their own results.

Chi-Square Distribution↗
PubMed1998

Prevalence and predictors of long-term work disability due to carpal tunnel syndrome.

The objective of this study was to describe patterns and predictors of work absence in the prospective, community-based Maine Carpal Tunnel Study. Three hundred fifteen patients with carpal tunnel syndrome (CTS) were recruited from physicians' offices throughout Maine. The patients completed questionnaires at entry and after 6, 18, and 30 months. The questionnaires included scales measuring symptom severity, functional status, general and mental health status, exposure to physical stressors, work status, and other indicators. The analyses examined univariate and multivariate correlates of work absence. The mean age was 43, 72% of subjects were female, 71% underwent carpal tunnel release, and 45% were receiving Workers' Compensation. Fifty-two percent worked in managerial or technical occupations, 15% in service occupations, and 13% in heavy labor or machine operation. Forty-five percent of patients changed jobs or were absent from work (aside from postoperative recovery) during the 30-month follow-up. In multivariate logistic regression models, correlates of work absence at 18 months included worse functional status of the hand at study entry and at 6-month follow-up, involvement of an attorney at the time of enrollment (P < 0.002 for each), and work absence at 6 months (P = 0.03). Worse upper extremity functional status and having a contested Workers' Compensation claim are critical predictors of work absence and should be principal targets of interventions to reduce work disability in CTS.

Absenteeism↗
PubMed1998

Maine Carpal Tunnel Study: small area variations.

As is the case for all elective procedures, small area variations occur in rates of surgery for carpal tunnel syndrome. A 1993 analysis of Maine data demonstrates that carpal tunnel release rates across population-based service areas varied 3.5-fold, from 0.82 to 2.87 per thousand. Four areas had rates significantly higher and 2 were significantly lower than the state average of 1.44 per thousand. Among many potential factors influencing variations, physician practice patterns appear to be the major contributor.

Carpal Tunnel Syndrome↗
PubMed1998

Maine Carpal Tunnel Study: outcomes of operative and nonoperative therapy for carpal tunnel syndrome in a community-based cohort.

A prospective, community-based, observational study of the outcome of surgical and nonoperative management was conducted. The study included 429 patients with carpal tunnel syndrome recruited in physicians' offices throughout Maine. Patients were assessed at baseline and at 6, 18, and 30 months following presentation using validated scales that measured symptom severity, functional status, and satisfaction. Seventy-seven percent of eligible survivors from the original cohort were monitored for 30 months. Surgically treated patients demonstrated improvements of 1.2 to 1.6 points on the 5-point Symptom Severity and Functional Status scales (23% to 45% improvement in scores), which persisted over the 30-month follow-up period. The nonoperatively managed patients showed little change in clinical status at 6, 18, and 30 months. While workers' compensation recipients had worse outcomes than nonrecipients, 36 of 68 (53%) workers' compensation recipients were completely or very satisfied with the results of the procedure 30 months after surgery. There were no significant differences in outcome between patients treated with endoscopic versus open carpal tunnel release. Among worker's compensation recipients, 12 of 68 (18%) surgical patients and 4 of 32 (13%) nonoperatively treated patients remained out of work because of carpal tunnel syndrome at 30 months. Thus, carpal tunnel surgery offered excellent symptom relief and functional improvement in this prospective community-based sample, irrespective of the surgical approach, even in workers' compensation recipients. Work absence remained high in both surgically and nonoperatively managed workers' compensation recipients.

Aged↗
PubMed1998

Physician partnering in Maine: an update from the Maine Medical Assessment Foundation.

BACKGROUND: The Maine Medical Assessment Foundation (MMAF) has involved the participation of hundreds of physicians in study groups to analyze data on small-area variation and assess physician decision-making patterns. In 1991 the MMAF model was replicated across a tri-state area (Maine, New Hampshire, and Vermont) in an effort called the Outcomes Dissemination Project. THE OUTCOMES DISSEMINATION PROJECT: Five specialty study groups, each meeting three times a year, examined local and national utilization data and guidelines and research findings, participated in outcomes studies and patient education, and disseminated their findings through society presentations and other feedback efforts. Physician surveys indicated that all but one of the study groups were successful in making their existence and activities known to the broader medical community. PARTNERING WITH PURCHASERS AND MEDICAID: In the "Partnership Projects," the MMAF and relevant study groups, collaborating with a Maine business coalition, analyzed variations in utilization across employers, types of health plans (for example, health maintenance organization, preferred provider organization, fee-for-service), and small areas. Through this process, coalition members learned about small-area analysis and the implications of variations in utilization for cost and quality. The first year of the collaborative projects focused on several issues, including the development and dissemination of a practice guideline for the care of patients with chest pain; the dissemination of a practice guideline for the treatment of patients with acute low back pain; and a project designed to address cesarean section rates. SUMMARY: Innovative partnerships have been crafted to allow the tenets of the MMAF's working relationships with the medical community to remain intact, ensuring the ongoing interest and cooperation of hundreds of Maine physicians.

Community Networks↗
PubMed1998

Comparative responsiveness of generic versus disease-specific and weighted versus unweighted health status measures in carpal tunnel syndrome.

OBJECTIVES: The authors evaluated the relative responsiveness to change of generic versus disease-specific and unweighted versus weighted health status measures in carpal tunnel syndrome (CTS). METHODS: Data were obtained from 196 subjects followed in a prospective community-based cohort study in Maine who underwent carpal tunnel release (The Maine Carpal Tunnel Syndrome Study). Patients were evaluated before and 6 months after surgery. The disease-specific, unweighted severity score was derived from the validated Carpal Tunnel Syndrome Assessment Questionnaire. Patients were asked to rate the importance of each symptom included in the severity score. Each severity question was weighted by its importance, creating a disease-specific weighted score. Generic instruments were the SF-36, SF-12, and a Quality of Life Rating Scale. Sensitivity to change was calculated with the standardized response mean (SRM, mean change/standard deviation of change) as well as the effect size (ES, mean change/standard deviation of baseline values). The ability of the instruments to distinguish clinically important differences was assessed by correlating the changes in scores with global ratings on satisfaction and perceived improvement as external criteria. RESULTS: The disease-specific weighted score (SRM: 1.56, ES: 1.99) was more responsive than the unweighted score (SRM: 1.36, ES: 1.57). The Quality of Life Rating Scale, SF-36, and SF-12 subscales were less sensitive to change, with standardized response means and effect sizes that ranged from -0.23 to 0.88. The ability to distinguish clinically important differences was higher for the two disease-specific scales. The coefficients of correlation with the external criteria ranged from 0.50 to 0.56 for the unweighted score and 0.56 to 0.62 for the weighted score and were significantly stronger than the correlations between external measures and the most responsive subscale of the SF-36 (Bodily Pain subscale, r = 0.36). The SF-12 health survey performed as well as the SF-36 in term of responsiveness and ability to distinguish clinically important change. CONCLUSIONS: Disease-specific measures were superior to generic measures in capturing clinical change after carpal tunnel release, and a weighted score was slightly more responsive than the unweighted score. The SF-12 showed comparable psychometric properties compared with the longer 36-item Short-Form Survey.

Adult↗
PubMed1997

Predictors of return to work following carpal tunnel release.

Little is known about factors that predict return to work following carpal tunnel release. Patients enrolled in a prospective, community-based study of carpal tunnel syndrome in Maine were evaluated with standardized questionnaires preoperatively and 6 months following carpal tunnel release. Univariate and multivariate analyses were performed to identify baseline factors associated with work disability 6 months following surgery. Thirty-one of 135 patients (23%) were out of work because of CTS 6 months following surgery. The predominant preoperative variables associated with work absence due to CTS 6 months postoperatively in logistic regression analyses were Workers' Compensation, work absence preoperatively, and worse mental health status (p < or = 0.01 for each). In analyses that considered postoperative as well as preoperative variables, persistence of symptoms following surgery was the most striking predictor of failure to return to work due to CTS (p < 0.0001). Preoperative correlates of less complete relief of symptoms in multivariate models included involvement of an attorney, milder preoperative symptom severity, preoperative work absence (p < 0.005 for each) and exposure to hand intensive work (p = 0.04). These data indicate that economic and psychosocial variables have a strong influence upon both return to work and the extent of symptom relief 6 months following surgery for carpal tunnel syndrome.

Adult↗
PubMed1997

Do physicians do what they say? The inclination to test and its association with coronary angiography rates.

OBJECTIVE: Efforts to evaluate variations in cardiac procedures have focused on patient factors and differences in health care delivery systems. We wanted to assess how physicians' inclination to test patients with coronary artery disease influences utilization patterns. SETTING AND SUBJECTS: Physicians and the populations of Maine, New Hampshire, and Vermont. DESIGN: We conducted a survey of 263 family practitioners, internists, and cardiologists residing in 57 hospital service areas in Maine, New Hampshire, and Vermont. Using patient scenarios, we assessed the clinicians' inclinations to test during the evaluation of patients with coronary artery disease. Self-reported testing intensities were used to create three indices: a Catheterization Index, an Imaging Exercise Tolerance Test (ETT) Index, and Nonimaging ETT Index. Using administrative data, age- and gender-adjusted population-based coronary angiography rates were calculated. Physicians were assigned to low (2.9/1,000), average (4.2/1,000), and high (5.8/1,000) coronary angiography rate areas, based on where they practice. Analysis of variance techniques were used to assess the relation of the index scores to the population-based coronary angiography rates and to physician specialties. RESULTS: There was a positive relationship between the population-based coronary angiography rates and the self-reported scores of the Catheterization Index (p < .005) and the Imaging ETT Index (p = .01), but none was found for the Non-imaging ETT Index (p = .10). These relationships were evident in subanalyses of cardiologists and internists, but not of family practitioners. CONCLUSIONS: Self-reported testing intensity by physicians is related to the population-based rates of coronary angiography. This relationship cuts across specialties, suggesting that there is a "medical signature" for the evaluation of patients with coronary artery disease.

Adult↗
PubMed1997

Patients' preferences and their relationship with satisfaction following carpal tunnel release.

Patients' preferences for specific health outcomes in carpal tunnel syndrome (CTS) and their association with demographic factors and satisfaction with the results of surgery after 6 months were evaluated. Two hundred fifty subjects with CTS and enrolled in a prospective community-based cohort study in Maine completed a preference questionnaire before surgery. Patients were asked to specify the single most important reason they decided to undergo surgery and to rate the importance of improvement in 10 areas, including lessening of specific symptoms and improvement in specific functional states related to CTS. The single most important reason for CTS patients to have surgery was relief of night pain (37%), followed by relief of numbness (21%) and relief of daytime pain (13%). When patients were asked to rate the importance of obtaining relief from specific symptoms and improvement in specific functional states, relief of numbness received the highest rating, with 94% of the patients answering that it was extremely or very important. Workers' compensation recipients, patients with less than a college level of education, and patients with more severe symptoms and functional impairment at baseline assigned higher importance to symptom relief and functional improvement. Controlling for other predictors, higher preference for improved strength was associated with lower satisfaction with the results of the surgery at 6 months. Most CTS patients undergoing surgery have realistic preferences for health outcomes that are influenced by demographic and clinical characteristics; however, physicians should pay attention to unrealistic preferences that might influence patients' satisfaction with surgical results.

Carpal Tunnel Syndrome↗
PubMed1997

Changing physician behavior: the Maine Medical Assessment Foundation.

Methods to produce change in physician practice patterns are of increasing importance to payers and regulators as well as to physicians themselves. Because some of the strategies being adopted occur without physician input and participation, they have aroused concern in the medical community. We describe the methods used and results achieved by the Maine Medical Assessment Foundation, a nonprofit education and research organization, that has been active in practice pattern analysis since the late 1970s. The foundation has successfully engaged clinicians in a program of systematic assessment of medical care provided to residents of Maine. Significant change in practice patterns has been documented. Physicians have become active participants in the process of voluntary self-assessment, education, and quality improvement.

Databases, Factual↗
PubMed1997

Prognostic value of a hand symptom diagram in surgery for carpal tunnel syndrome.

OBJECTIVE: To evaluate symptom patterns on a hand diagram as predictors of surgical outcome in carpal tunnel syndrome (CTS). METHODS: 202 patients with CTS enrolled in a prospective, community based cohort study in Maine completed a hand symptom diagram before surgery and at 6 month followup. They were asked to mark on the hand diagram the location of 3 symptoms: pain, numbness/tingling (NT), and "other" symptoms. The diagram was first divided into 6 regions following a standardized procedure. For the 6 regions, symptom patterns were identified separately for each of the 3 symptoms. Outcomes 6 months after surgery were expressed as the percentage of change on the Symptom Severity Scale and Function Status Scale of the Carpal Tunnel Syndrome Assessment Questionnaire, and the satisfaction with the results of the surgery. RESULTS: Several distinct symptom patterns were associated with the 3 principal outcomes in univariate and multivariate analysis. In linear regression models controlling for the baseline severity of symptoms and function, as well as other predictors, the hand symptom pattern variables accounted for 30, 14, and 24%, respectively, of the total explained variance in satisfaction, symptom severity, and functional status. Patients receiving Workers' Compensation (37% of the cohort) had more wrist pain and NT of the arm, and less pain involving the arm and upper palm. This group also had worse outcomes and were less satisfied with surgery. Drawing expansion was associated with a low score on the SF-36 mental health subscale. However, psychological impairment was not associated with a worse outcome. CONCLUSION: Symptom patterns identified preoperatively with a hand symptom diagram help to predict the outcome of carpal tunnel release.

Adult↗
PubMed1996

The Quebec Task Force classification for Spinal Disorders and the severity, treatment, and outcomes of sciatica and lumbar spinal stenosis.

STUDY DESIGN: A prospective cohort study of patients in Maine with sciatica and lumbar spinal stenosis treated surgically and nonsurgically. SUMMARY OF BACKGROUND DATA: In 1987, the Quebec Task Force on Spinal Disorders proposed a diagnostic classification to help make clinical decisions, evaluate quality of care, assess prognosis, and conduct research. OBJECTIVES: To assess the Quebec Task Force classification's ability to stratify patients according to severity and treatment at baseline, and to assess changes over time in health-related quality of life, including symptoms, functional status, and disability. METHODS: Five hundred sixteen patients participating in the Maine Lumbar Spine Study who completed baseline and 1-year follow-up evaluations were classified successfully according to the Quebec Task Force classification. Patient characteristics and treatments were compared across Quebec Task Force classification categories. Changes in health-related quality of life over 1 year were assessed according to Quebec Task Force classification category and type of treatment. RESULTS: Among patients with sciatica (n = 370), higher Quebec Task Force classification categories (from 2, pain radiating to the proximal extremity, to 6, sciatica with evidence of nerve root compression) were associated with increased severity of symptoms at baseline. There was no association between Quebec Task Force classification and baseline functional status. Quebec Task Force classification was associated strongly with the likelihood of receiving surgical treatment (P < or = 0.005). Among patients with sciatica treated nonsurgically, improvement at 1 year in back-specific and generic physical function increased with higher Quebec Task Force classification category (P < or = 0.05). Only a nonsignificant trend was observed for surgically treated patients. Patients with lumbar spinal stenosis (Quebec Task Force classification 7, n = 131) had baseline features and outcomes distinct from patients with sciatica. CONCLUSIONS: For patients with sciatica, the Quebec Task Force classification was highly associated with the severity of symptoms and the probability of subsequent surgical treatment. Nonsurgically treated patients in Quebec Task Force classification categories reflecting nerve root compression had greater improvement than those with pain symptoms alone. Among surgical patients, the Quebec Task Force classification was not associated with outcome. These results provide validation for the classification and its wider adoption. Nonetheless, improved diagnostic classifications are needed to predict outcomes better in patients with sciatica who undergo surgery.

Adolescent↗
PubMed1996

The Maine Lumbar Spine Study, Part I. Background and concepts.

STUDY DESIGN: This paper describes the background and factors that led to the development and implementation of the Maine Lumbar Spine Study, a prospective cohort study of patients undergoing surgical and nonsurgical treatment of herniated lumbar disc with sciatica and symptomatic spinal stenosis. OBJECTIVES: To define the factors leading to the study and the methods of designing and implementing a community-based effectiveness study to evaluate the outcomes of herniated lumbar intervertebral disc and spinal stenosis. SUMMARY OF BACKGROUND DATA: Variations in the utilization of surgery for these conditions and physicians' uncertainty regarding the best way to manage them resulted in support of a community-based study of the effectiveness of treatment alternatives. METHODS: A prospective cohort design was used. Methods of patient enrollment, data collection, management, and analysis are described. An innovative method of ascertaining the representativeness of the enrolled versus nonenrolled patient population is presented. RESULTS: The importance of developing community-based networks of physicians is discussed. CONCLUSIONS: These networks play an important role in analyzing practice pattern variations and in stimulating and participating in effectiveness research. Because effectiveness studies must be conducted at the community level, mechanisms must be developed with which to support and implement these efforts.

Cohort Studies↗