What can the history and physical examination tell us about low back pain?
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Back Pain↗
Biomedical subjects
R A Deyo
Publications and source records attributed to R A Deyo.
Nifedipine blocks retention of a visual discrimination task in chicks.
Reports that the dihydropyridine Ca2+ channel antagonists may facilitate memory led to the present study of the behavioral effects of nifedipine. Ninety-two 4-day-old male chicks received 0, 100 nM, 100 microM, or 10 mM nifedipine. Drugs were administered in volumes of 2 microliters into the fourth cerebral ventricle 5 min before training on a visual discrimination task. Nifedipine did not produce any detectable changes in behavior during acquisition trials. Retention, however, was impaired 24 h after training in the 100 nM and 100 microM nifedipine-treated chicks, which made significantly more errors than controls. Nifedipine did not affect the amount of time required to complete the task. No effects on body weight gain were detected, suggesting that the memory impairment was not due to a change in feeding behavior. These data are discussed in terms of the role of calcium-dependent processes in memory.
Animals↗
Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases.
Administrative databases are increasingly used for studying outcomes of medical care. Valid inferences from such data require the ability to account for disease severity and comorbid conditions. We adapted a clinical comorbidity index, designed for use with medical records, for research relying on International Classification of Diseases (ICD-9-CM) diagnosis and procedure codes. The association of this adapted index with health outcomes and resource use was then examined with a sample of Medicare beneficiaries who underwent lumbar spine surgery in 1985 (n = 27,111). The index was associated in the expected direction with postoperative complications, mortality, blood transfusion, discharge to nursing home, length of hospital stay, and hospital charges. These associations were observed whether the index incorporated data from multiple hospitalizations over a year's time, or just from the index surgical admission. They also persisted after controlling for patient age. We conclude that the adapted comorbidity index will be useful in studies of disease outcome and resource use employing administrative databases.
Aged↗
Strategies for improving and expanding the application of health status measures in clinical settings. A researcher-developer viewpoint.
Health status instruments may be useful in clinical settings to screen for functional problems, monitor disease progression or therapeutic response, improve doctor-patient communications, assess quality of care, or provide case-mix adjustment for comparing other outcomes between patient groups. However, conceptual, practical, and attitudinal barriers have prevented their wider implementation. Aside from providing more data on how these measures influence the process and outcomes of clinical care, several strategies may help to improve and expand their application. Wider application would be promoted by training health care providers about the methods of health status assessment, their validity, and the available instruments; comparing newer functional measures and older scales with which clinicians are familiar (to make scores more meaningful); providing better data for the selection of instruments; and improving the responsiveness of these questionnaires to clinical changes. If health status measures are used in direct patient care, it is important to determine whether the goal is to screen for functional problems or to monitor patient changes over time. These different purposes may influence the selection of instruments, the types of patients targeted (e.g., based on age or diagnosis), and the frequency of patient assessment. Health status measures must be easily incorporated into the office routine, requiring that they be brief, easy to interpret, and not require complex training or scoring algorithms. In this setting, it may be helpful to provide clinicians not only with functional status scores, but with interpretations and recommendations about management or community resources to consider. The costs of health status measurement and data analysis will probably be borne by third-party payers, who must be persuaded of their utility. When health status measures are used for quality assurance, average scores for groups of patients should be adjusted for disease severity, comorbid conditions, demographic characteristics, socioeconomic status, and baseline health status. Furthermore, the sickest or most vulnerable members of a clinical population may be least able to provide valid health status information because of dementia, frailty, blindness, illiteracy, or inability to speak English. These patients may be of particular interest, and are likely to alter average health status scores for a population, so methods to assure complete ascertainment must be considered.
Attitude of Health Personnel↗
Use of the International Classification of Diseases (ICD-9-CM) to identify hospitalizations for mechanical low back problems in administrative databases.
Large administrative databases are increasingly valuable tools for health care research. Although increased access to these databases provides valuable opportunities to study health care utilization, costs and outcomes and valid and comparable results require explicit and consistent analytic methods. Algorithms for identifying surgical and nonsurgical hospitalizations for "mechanical" low back problems in automated databases are described. Sixty-six ICD-9-CM diagnosis and 15 procedure codes that could be applied to patients with mechanical low back problems were identified. Twenty-seven diagnosis and two procedure codes identify hospitalizations for problems definitely in the lumbar or lumbosacral region. Exclusion criteria were developed to eliminate nonmechanical causes of low back pain, such as malignancies, infections, and major trauma. The use of the algorithms is illustrated using national hospital discharge data.
Algorithms↗
Diagnosis of lumbar spinal stenosis in adults: a metaanalysis of the accuracy of CT, MR, and myelography.
We undertook a literature synthesis of CT, MR, and myelographic studies to evaluate what is known about the diagnostic accuracy of these imaging tests for the diagnosis of lumbar spinal stenosis in adults without prior surgery. From 116 possibly relevant studies, we reviewed 14 articles that included cases of spinal stenosis with a reference standard other than the imaging tests of interest. Of the studies we reviewed, two involved only MR, nine only CT, and three used both; six studies included myelography. Rating categories of A, B, C, or D were assigned for the quality of research methods used to estimate diagnostic accuracy. All studies received either a C or D rating. Common methodologic problems were failure to assemble a representative cohort for study, small sample size, and failure to maintain independence between image readings and reference standards. Sensitivity ranged from 0.81 to 0.97 for MR, from 0.70 to 1.0 for CT, and from 0.67 to 0.78 myelography. Studies varied greatly in case selection, definition of test and disease categories, and geographic locale, so no pooled estimates could be derived. In asymptomatic patients, abnormal findings appeared on CT or MR in 4-28% of cases and were more common in the elderly. Published studies of the value of CT and MR for the diagnosis of lumbar stenosis lack methodologic rigor and do not permit strong conclusions about the relative diagnostic accuracies of these procedures. For the present, the choice between MR or CT depends on issues such as costs, reimbursements, access to equipment, skill of radiologists, and patient safety. Better studies will be needed to document claims for improvements in imaging accuracy as MR technologies evolve. These studies should emphasize larger sample sizes, more attention to research designs that avoid methodologic biases, and the contribution of imaging diagnoses to ultimate clinical outcome.
Evaluation Studies as Topic↗
Morbidity and mortality in association with operations on the lumbar spine. The influence of age, diagnosis, and procedure.
We examined the rates of postoperative complications and mortality, as recorded in a hospital discharge registry for the State of Washington for the years 1986 through 1988, for patients who had had an operation on the lumbar spine. When patients who had had a malignant lesion, infection, or fracture are excluded, there were 18,122 hospitalizations for procedures on the lumbar spine, 84 per cent of which involved a herniated disc or spinal stenosis. The rates of morbidity and mortality during hospitalization, as well as the hospital charges, increased with the ages of the patients. The rate of complications was 18 per cent for patients who were seventy-five years or older. Nearly 7 per cent of patients who were seventy-five years old or more were discharged to nursing homes. Complications were most frequent among patients who had spinal stenosis, but multivariate analysis suggested that the complications associated with procedures for this condition were primarily related to the patient's age and the type of procedure. Complications, length of hospitalization, and charges were higher for patients who had had a spinal arthrodesis than for those who had not. Over-all, operations for conditions other than a herniated disc were associated with more complications and greater use of resources, particularly when arthrodesis was performed, than were operations for removal of a herniated disc. No data on symptoms or functional results were available.
Adolescent↗
Fads in the treatment of low back pain.
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Adrenal Cortex Hormones↗
The quality of life, research, and care.
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Humans↗
Reproducibility and responsiveness of health status measures. Statistics and strategies for evaluation.
Before being introduced to wide use, health status instruments should be evaluated for reliability and validity. Increasingly, they are also tested for responsiveness to important clinical changes. Although standards exist for assessing these properties, confusion and inconsistency arise because multiple statistics are used for the same property; controversy exists over how to measure responsiveness; many statistics are unavailable on common software programs; strategies for measuring these properties vary; and it is often unclear how to define a clinically important change in patient status. Using data from a clinical trial of therapy for back pain, we demonstrate the calculation of several statistics for measuring reproducibility and responsiveness, and demonstrate relationships among them. Simple computational guides for several statistics are provided. We conclude that reproducibility should generally be quantified with the intraclass correlation coefficient rather than the more common Pearson r. Assessing reproducibility by retest at one-to-two week intervals (rather than a shorter interval) may result in more realistic estimates of the variability to be observed among control subjects in a longitudinal study. Instrument responsiveness should be quantified using indicators of effect size, a modified effect size statistic proposed by Guyatt, or the use of receiver operating characteristic (ROC) curves to describe how well various score changes can distinguish improved from unimproved patients.
Analysis of Variance↗
Diagnostic accuracy and clinical utility of thermography for lumbar radiculopathy. A meta-analysis.
The role of thermography for diagnosing lumbar radiculopathy was evaluated by literature review and meta-analysis. From 81 relevant citations, 28 studies could be analyzed for diagnostic-accuracy data (sensitivity and specificity) and method. Diagnostic-accuracy data varied significantly between studies; therefore meaningful pooled summary statistics could not be reported. Twenty-seven studies had major methodologic flaws including biased test interpretations, faulty cohort assembly, poor clinical descriptions, and small sample size. The only study of reasonably high quality found no discriminant value for liquid-crystal thermography. The role of thermography remains unclear. Rigorous clinical research is required to establish its diagnostic accuracy and clinical utility. Thermography cannot be recommended currently for routine clinical use in evaluating low-back pain.
Back Pain↗
Evaluation of a physician education intervention to improve primary care for low-back pain. I. Impact on physicians.
In an effort to improve the cost-effectiveness of primary care for low-back pain, we developed, implemented, and evaluated a physician education intervention. The program was designed to provide family physicians with specific information, tools, and techniques that our previous studies and the literature suggested should be associated with more satisfying and cost-effective care for low-back pain. The in-clinic educational intervention included feedback of the findings of our previous studies of care for back pain (comparing family physicians and chiropractors), an up-to-date summary of scientific knowledge relevant to the management of back pain in primary care, a videotape contrasting ineffective and effective patient encounters, and a clinical assessment form for low-back pain. The back pain-related beliefs, attitudes, and behaviors of 15 primary care providers in a large health maintenance organization clinic and of 14 family physicians in six group practices were assessed before and after the intervention. Significant increases were noted in the proportions of providers who felt confident they knew how to manage low-back pain, who believed their patients were satisfied, and who claimed they reassured patients that they did not have serious disease. The intervention, however, had little impact on the prevalence of negative feelings about patients with back pain or frustration with patients who wanted their doctor to "fix" their problem. The intervention had a similar impact on health maintenance organization and fee-for-service physicians.
Back Pain↗
Evaluation of a physician education intervention to improve primary care for low-back pain. II. Impact on patients.
A physician education intervention was previously found to have significantly improved perceived physician knowledge, confidence, and patient-reassuring behavior in the treatment of low-back pain. This study examined whether this intervention, presented in a health maintenance organization clinic, had an effect on patient outcomes. Outcomes of care for 148 patients seen for low-back pain before the intervention were compared with outcomes of care for 157 patients seen after the intervention. Patients were telephoned 2-4 weeks after their back-pain visit and were asked about symptom improvement, amount of disability, and satisfaction with care. Satisfaction was measured with a three-dimensional instrument for low-back pain developed specifically for this study, which was found to be valid and reliable. The preintervention and postintervention patient cohorts were similar in terms of key baseline variables. Despite its apparent benefit to physicians, the intervention did not result in significant improvements in any patient outcomes, even for the subset of patients whose physicians had perceived the greatest benefit.
Back Pain↗
Cost, controversy, crisis: low back pain and the health of the public.
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Back Pain↗
Risk factors for suicide attempts among Navajo adolescents.
BACKGROUND: Rates of adolescent suicide in the United States are highest among Native Americans but little is known about risk factors for suicide attempts in this population. METHODS: To identify risk factors for self-reported suicide attempts by Navajo adolescents, we analyzed the 1988 Indian Health Service Adolescent Health Survey that was administered to 7,254 students in grades 6 through 12 on the Navajo reservation. The responses of students reporting a past suicide attempt were compared to others. RESULTS: Nearly 15 percent (N = 971) reported a previous suicide attempt; over half of those admitted to more than one attempt. Controlling for age, a logistic regression model revealed the following associations with suicide attempts: a history of mental health problems (OR = 3.2); alienation from family and community (OR = 3.2); having a friend who attempted suicide (OR = 2.8); weekly consumption of hard liquor (OR = 2.7); a family history of a suicide or attempt (OR = 2.3); poor self-perception of health (OR = 2.2); a history of physical abuse (OR = 1.9); female gender (OR = 1.7); and sexual abuse (OR = 1.5). CONCLUSIONS: Efforts to prevent adolescent suicide attempts in this population should target individuals with those risk factors of the highest risk and prevalence of exposure.
Adolescent↗
Nonsurgical care of low back pain.
Based on accumulating evidence, an important shift in the nonsurgical treatment paradigm for low back pain is underway. This shift is away from prolonged rest and passive therapy toward earlier patient activation and greater use of exercise therapy. The patient's best interest is often served by encouraging an early return to work and by avoiding adversarial legal proceedings. Patients should be reassured about the good prognosis of acute pain, and the alarming terminology of "injury" or "ruptured disc" should be avoided. Intervention to avoid sedentariness, smoking, and obesity probably offers important therapeutic and preventive opportunities. When surgery is indicated, the patient should have a major role in decision making after being provided an accurate view of risks and benefits of surgical intervention. Surgery should generally be reserved for those cases for which a benefit of surgery has been clearly established, avoiding the liberalization of indications to include imaging findings alone, persistent pain alone, or the failure of other treatments in the absence of clear surgical indications.
Back Pain↗
Nimodipine enhances spontaneous activity of hippocampal pyramidal neurons in aging rabbits at a dose that facilitates associative learning.
The functional activity of hippocampal neurons is strongly correlated with behavioral performance in a vertebrate model learning system, rabbit eyeblink conditioning. Using this system, we have previously shown that (a) complete removal of the hippocampus blocks acquisition of the conditioned response; (b) a calcium-dependent postsynaptic afterhyperpolarization is reduced in pyramidal cells recorded intracellularly in hippocampal slices taken from conditioned rabbits; and (c) nimodipine, a 1,4-dihydropyridine calcium-channel antagonist, facilitates acquisition of the conditioned response in aging rabbits. Although calcium-channel antagonists directly block neuronal calcium currents in vitro, they also alter cerebral blood flow in vivo. Thus, the effects of nimodipine on hippocampal neuronal activity in awake animals were examined, with controls for cerebrovascular changes. A total of 457 pyramidal cells and 160 theta cells were studied. During infusion of nimodipine, pyramidal cell firing activity was enhanced and theta interneuron activity was suppressed at all doses tested in aging animals. This effect was rapidly reversed when infusion of the drug ceased. The greatest enhancement of neuronal firing was seen at the most behaviorally effective dose of nimodipine. The enhancement of pyramidal cell firing was age-dependent, with greater increases in firing activity seen in aging than in young animals, but with a similar dose-dependent pattern of effects in the two age groups. Two other calcium-channel antagonists, nifedipine and flunarizine, did not significantly alter spontaneous firing rates of hippocampal neurons. A calcium-channel agonist, BAY-K-8644, produced less easily interpretable results. BAY-K-8644 enhanced interneuron activity at one dose, but enhanced pyramidal cell activity at a dose one log unit higher. The calcium-channel agonist's enhancement of pyramidal cell activity at the highest dose was sustained up to 1 h after drug infusion. Nimodipine's enhancement of the activity of hippocampal pyramidal cells is consistent with the hypothesis that these neurons, which play a necessary role in some forms of learning, may mediate the calcium-channel antagonist's behavioral effects.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
A controlled trial of transcutaneous electrical nerve stimulation (TENS) and exercise for chronic low back pain.
A number of treatments are widely prescribed for chronic back pain, but few have been rigorously evaluated. We examined the effectiveness of transcutaneous electrical nerve stimulation (TENS), a program of stretching exercises, or a combination of both for low back pain. Patients with chronic low back pain (median duration, 4.1 years) were randomly assigned to receive daily treatment with TENS (n = 36), sham TENS (n = 36), TENS plus a program of exercises (n = 37), or sham TENS plus exercises (n = 36). After one month no clinically or statistically significant treatment effect of TENS was found on any of 11 indicators of outcome measuring pain, function, and back flexion; there was no interactive effect of TENS with exercise. Overall improvement in pain indicators was 47 percent with TENS and 42 percent with sham TENS (P not significant). The 95 percent confidence intervals for group differences excluded a major clinical benefit of TENS for most outcomes. By contrast, after one month patients in the exercise groups had significant improvement in self-rated pain scores, reduction in the frequency of pain, and greater levels of activity as compared with patients in the groups that did not exercise. The mean reported improvement in pain scores was 52 percent in the exercise groups and 37 percent in the nonexercise groups (P = 0.02). Two months after the active intervention, however, most patients had discontinued the exercises, and the initial improvements were gone. We conclude that for patients with chronic low back pain, treatment with TENS is no more effective than treatment with a placebo, and TENS adds no apparent benefit to that of exercise alone.
Back Pain↗