The relationship between submaximal activity of the lumbar extensor muscles and lumbar posteroanterior stiffness.
BACKGROUND AND PURPOSE: Some patients with low back pain are thought to have increased lumbar posteroanterior (PA) stiffness. Increased activity of the lumbar extensors could contribute to this stiffness. This activity may be seen when a PA force is applied and is thought to represent much less force than occurs with a maximal voluntary contraction (MVC). Although MVCs of the lumbar extensors are known to increase lumbar PA stiffness, the effect of small amounts of voluntary contraction is not known. In this study, the effect of varying amounts of voluntary isometric muscle activity of the lumbar extensors on lumbar PA stiffness was examined. SUBJECTS: Twenty subjects without low back pain, aged 26 to 45 years (X=34, SD=5.6), participated in the study. METHODS: Subjects were asked to perform an isometric MVC of their lumbar extensor muscles with their pelvis fixed by exerting a force against a steel plate located over their T4 spinous process. They were then asked to perform contractions generating force equivalent to 0%, 10%, 30%, 50%, and 100% of that obtained with an MVC. Posteroanterior stiffness at L4 was measured during these contractions. RESULTS: A Friedman one-way analysis of variance for repeated measures demonstrated a difference in PA stiffness among all levels of muscle activity. CONCLUSION AND DISCUSSION: Voluntary contraction of the lumbar extensor muscles will result in an increase in lumbar PA stiffness even at low levels of activity. (+info)
SF 36 health survey questionnaire: I. Reliability in two patient based studies.
OBJECTIVE: To assess the reliability of the SF 36 health survey questionnaire in two patient populations. DESIGN: Postal questionnaire followed up, if necessary, by two reminders at two week intervals. Retest questionnaires were administered postally at two weeks in the first study and at one week in the second study. SETTING: Outpatient clinics and four training general practices in Grampian region in the north east of Scotland (study 1); a gastroenterology outpatient clinic in Aberdeen Royal Hospitals Trust (study 2). PATIENTS: 1787 patients presenting with one of four conditions: low back pain, menorrhagia, suspected peptic ulcer, and varicose veins and identified between March and June 1991 (study 1) and 573 patients attending a gastroenterology clinic in April 1993. MAIN MEASURES: Assessment of internal consistency reliability with Cronbach's alpha coefficient and of test-retest reliability with the Pearson correlation coefficient and confidence interval analysis. RESULTS: In study 1, 1317 of 1746 (75.4%) correctly identified patients entered the study and in study 2, 549 of 573 (95.8%). Both methods of assessing reliability produced similar results for most of the SF 36 scales. The most conservative estimates of reliability gave 95% confidence intervals for an individual patient's score difference ranging from -19 to 19 for the scales measuring physical functioning and general health perceptions, to -65.7 to 65.7 for the scale measuring role limitations attributable to emotional problems. In a controlled clinical trial with sample sizes of 65 patients in each group, statistically significant differences of 20 points can be detected on all eight SF 36 scales. CONCLUSIONS: All eight scales of the SF 36 questionnaire show high reliability when used to monitor health in groups of patients, and at least four scales possess adequate reliability for use in managing individual patients. Further studies are required to test the feasibility of implementing the SF 36 and other outcome measures in routine clinical practice within the health service. (+info)
SF 36 health survey questionnaire: II. Responsiveness to changes in health status in four common clinical conditions.
OBJECTIVE: To assess the responsiveness of the SF 36 health survey questionnaire to changes in health status over time for four common clinical conditions. DESIGN: Postal questionnaires at baseline and after one year's follow up, with two reminders at two week intervals if necessary. SETTING: Clinics and four training general practices in Grampian region in the north east of Scotland. PATIENTS: More than 1,700 patients aged 16 to 86 years with one of four conditions: low back pain, menorrhagia, suspected peptic ulcer, and varicose veins; and a random sample of 900 members of the local general population for comparison. MAIN MEASURES: A transition question measuring change in health and the eight scales of the SF 36 health survey questionnaire; standardised response means (mean change in score for a scale divided by the standard deviation of the change in scores) used to quantify the instrument's responsiveness to changes in perceived health status, and comparison of patient scores at baseline and follow up with those of the general population. RESULTS: The response rate exceeded 75% in a patient population. Changes across the SF 36 questionnaire were associated with self reported changes in health, as measured by the transition question. The questionnaire showed significant improvements in health status for all four clinical conditions, whether in referred or non-referred patients. For patients with suspected peptic ulcer and varicose veins the SF 36 profiles at one year approximate to the general population. CONCLUSIONS: These results provide the first evidence of the responsiveness of the SF 36 questionnaire to changes in perceived health status in a patient population in the United Kingdom. (+info)
An interactive videodisc program for low back pain patients.
Decisions about back pain treatment are often made in the presence of both physician and patient uncertainty. Therefore, we developed a computerized, interactive video program to help patients make informed decisions about undergoing low back surgery. Program development was guided by the shared decision-making model, a comprehensive literature synthesis, information from administrative databases, and focus groups of patients and physicians. Core segments are tailored to each patient's age and diagnosis; and include a narrative, excerpts from patient interviews, animated graphics illustrating spinal anatomy, and tabular summaries of the benefits and risks of both surgical and non-surgical treatment. As part of a multifocal information dissemination effort, interactive videodiscs were placed in five medical facilities in two Washington State counties. Patients (N = 239) who viewed the video program completed short evaluation forms. The majority rated the video's understandability (84%) and interest (64%) as very good or excellent. Most patients felt the amount of information provided was appropriate (75%) and over half (56%) believed the discussion of surgical versus non-surgical treatment was completely balanced. Fewer patients (17%) remained undecided about therapy after watching the program than before (29%). We conclude that interactive videodisc technology offers substantial promise as a means of involving patients in their own medical decision making. (+info)
Extradural inflammation associated with annular tears: demonstration with gadolinium-enhanced lumbar spine MRI.
Annular tears are manifest on MRI as the high-intensity zone (HIZ) or as annular enhancement. Patients with annular tears may experience low back pain with radiation into the lower limb in the absence of nerve root compression. Inflammation of nerve roots from leak of degenerative nuclear material through full-thickness annular tears is a proposed mechanism for such leg pain. The aim of this study is to illustrate the appearance of extradural enhancement adjacent to annular tears in patients being investigated for low back pain with radiation into the lower limb(s). Sagittal T1- and T2-weighted spin echo and axial T1-weighted spin echo sequences were obtained in eight patients being investigated for low back and leg pain. In all patients, the T1-weighted sequences were repeated following intravenous gadopentetate dimeglumine (Gd-DTPA). Annular tears were identified at 12 sites in eight patients. Extradural inflammation appeared as a region of intermediate signal intensity replacing the fat between the posterior disc margin and the theca, which enhanced following Gd-DTPA. The inflammatory change was always associated with an annular tear, and in four cases directly involved the nerve root. Enhancement of the nerve root was seen in two cases. The findings may be relevant in the diagnosis of chemical radiculopathy secondary to inflammation at the site of an annular leak from a degenerating disc. (+info)
The prevalence of low back pain in adults: a methodological review of the literature.
The prevalence of low back pain (LBP) has been reported in the literature for different populations. Methodological differences among studies and lack of methodological rigor have made it difficult to draw conclusions from these studies. A systematic review was done for adult community prevalence studies of LBP published from 1981 to 1998. The technique of capture-recapture was performed to estimate the completeness of the search strategy used. Established guidelines and a methodological scoring system were used to critically appraise the studies. Thirteen studies were deemed methodologically acceptable. Differences in the duration of LBP used in the studies appeared to affect the prevalence rates reported and explain much of the variation seen. It was estimated that the point prevalence rate in North America is 5.6%. Further studies using superior methods are needed, however, before this estimate can be used with confidence to make health care policies and decisions relating to physical therapy. (+info)
Prognostic factors for chronic disability from acute low-back pain in occupational health care.
OBJECTIVES: This study attempted to determine the prognostic indicators of low-back pain in an occupational health setting. METHODS: The identification of prognostic factors of (i) functional disability after 3 months' follow-up, (ii) functional disability after 12 months' follow-up, and (iii) time to return to work among 120 workers who reported to an occupational health unit and were off work with low-back pain for at least 10 days. Crude and adjusted odds ratios and hazard ratios with 95% confidence intervals were estimated for the 3 outcome measures. RESULTS: Factors related to a longer time to return to work were radiating pain, high functional disability at the beginning of the study, problems in relations with colleagues, and high work tempo and work quantity. High functional disability at the beginning of the study and a high avoidance coping style predicted functional disability at 3 months. Functional disability at 12 months was more accurately predicted by work-related and psychosocial factors. CONCLUSIONS: Especially radiating pain and functional disability predict a long duration of low-back pain in occupational health practice. Occupational physicians should also note work-related and psychosocial characteristics. (+info)
Maximizing use of a surgical clinic for referrals of patients having back problems.
OBJECTIVE: To determine ways to improve the delivery of service in a surgical clinic, based on the outcome of surgical consultations for back pain. DESIGN: A prospective outcome study. SETTING: A university teaching hospital providing secondary and tertiary care. PATIENTS: One hundred and forty-two consecutive patients who presented to surgical clinics for assessment of a back problem between Apr. 14 and May 30, 1996. INTERVENTIONS: Surgeons determined the diagnosis and visit outcome; data were tabulated objectively by a third-party researcher. OUTCOME MEASURES: Waiting time for consultation, presence of referral letter, third-party interests, diagnosis and visit outcome. RESULTS: Twenty-five percent of patients had chronic pain not amenable to surgery, 19% of patients were surgical candidates and were offered an operation, 13% were symptomatically improved to the point of not wanting an operation, 11% wanted a second opinion only, 10% had mechanical back pain appropriate for referral to physiotherapy, 9% had not undergone an adequate trial of nonoperative treatment when seen in the clinic and were given follow-up appointments, 5% were "no shows," 3.5% were seen for a medicolegal assessment, 3.5% wanted confirmation from a specialist that they did not need surgery and 1% had symptoms due to a vascular rather than a spinal cause and were referred to a vascular surgeon. CONCLUSION: Delivery of service could be improved by more rigorous screening to reassign appointment times of patients who have not had an adequate trial of nonoperative treatment, are improved or do not intend to keep their appointment. (+info)