Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Back”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53Linked to original sources
PubMed1988

Correlates of low back pain in a general population sample: a multidisciplinary perspective.

This study identifies correlates of low back pain in a general population sample and defines a profile of subjects with low back pain. A multidisciplinary approach was employed that required surveying and physically assessing 674 subjects on 105 variables in biographical, anatomical, strength and flexibility measurement categories. No attempt was made to select subjects from specific occupational, age, athletic, psychological and anatomical groups or subjects with specific biographical features, which may have resulted in a sample that was atypical of the general population. The results of this study based on a causal comparative ex post facto research design corroborated selected findings of previous research conducted on nongeneral population samples. These findings include relationships between low back pain and age, body type, sex, stress, smoking, selected types of physical activity, occupation and previous injuries to the neck, shoulders, back and upper legs, as well as previous episodes of low back pain. Additional correlates of low back pain that were identified and have little or controversial review in the back literature include: delayed low back pain syndrome caused by abrupt changes in running frequency, Q angle, pes cavus, leg length (right and left), trunk length, genu recurvatum and multiplane strength and flexibility limitations in the hip joints.

Adolescent↗
PubMed1982

Back complaints and findings in transport workers performing physically heavy work.

Transport work at an airport promotes the appearance of back diseases because of the lifting carrying, pulling, and pushing of loads in limited spaces. To clarify the nature of back disorders in such a group, a standardized interview for detecting subjective previous and present back symptoms was made of 366 transport workers, and 134 were given a clinical orthopedic examination for detecting objective findings. Sixty-six percent of the interviewed workers reported current back symptoms; these symptoms correlated significantly positively with height, age, and length of transport work experience. Eighty-three percent of te workers with present back symptoms also complained of former back pain. Validity tests between the interview and the clinical examination showed a sensitivity of 86% and a specificity of 31%. The results of our study suggest (i) that according to the high sensitivity the used interview is a valuable screening method for detecting back disorders, and (ii) that selection of workers according to the criteria of our results may be expected to lower the prevalence of back complaints.

Adult↗
PubMed1980

Back and leg complaints in relation to muscle strength in young men.

Back and leg complaints were studied by using a questionnaire and medical examination in 183 male conscripts and relating the results to background variables, anthropometry, the isometric strength of large muscle groups, and endurance running. A history of sciatica was reported by 8%, lumbago by 13%, back injury by 13% and low back insufficiency by 63%. Weak trunk extensors were associated with a history of sciatica, weak trunk flexors with back injuries and with current backache at work/exercise. Weak leg extensors showed associations with a history of low back insufficiency and of sick leave due to the back and with current hip pain. Men with a history of lumbago and of hip and knee complaints performed poorly during 12 min of running. Back and leg complaints were more frequent in men with high socio-economic status, who engaged in little physical activity, or who were obese. The questionnaire and strength measurements proved suitable for studying low back syndrome in its early stages.

Adult↗
PubMed1995

Clinical and psychological classification of non-specific low-back pain. A new study in primary care practice.

This study aimed to explore the clinical and psychological features of non-specific low-back pain (LBP), and to evaluate a classification of patients based on the relationship between psychological disturbances and LBP clinical presentation. An unselected population of consecutive patients (n = 262) complaining of low-back pain to primary care physicians of the Epidemiology Team of the French Rheumatology Society, in October and November 1991, was studied. Measures included a standardized clinical evaluation of the back and a psychological assessment using the General Health Questionnaire. Ninety nine patients (38%) were classified as having a psychological disorder. The following symptoms: psychological precipitating event, permanent pain at night, diffuse spinal pain, pain increased by changing climate, pain increased by psychological factors, dysesthesias in the back, non-anatomical tenderness, were found to be closely associated with the existence of psychological disorder. Correspondence and cluster analyses provided support for the four-group classification of low-back pain previously devised. This classification may be interpreted through the relationships between psychological disturbances and the back clinical features. Although the study was mainly descriptive and used a cross sectional design, its results underline the importance of psychological influence on low-back pain presentation, and suggest the interest of a psychiatric assessment in low-back pain patients. Psychological disorders appear to be frequent in these patients and specific management of these disorders may prove useful.

Adolescent↗
PubMed1994

Functional approach to treatment of back pain in primary care: a preliminary report.

BACKGROUND: Back pain is one of the most common problems encountered in primary care clinics and causes great loss of work time, economy and expenditure of medical care. Knowledge of the cause of low back pain and effective treatment are rudimentary. We studied the functional approach to treatment of back pain of two acute (M:F = 1:1) and thirty chronic (M:F = 12:18) patients with back pain seen at a rural primary care clinic in September and October 1992. METHODS: Patients were included after completing an agreement form regarding the treatment plan (emphasizing therapeutic exercise, health education and as little medication as possible) in the first interview. A primary care physician specialised in family medicine personally gave treatment to the patients with free attendance to the clinic. A functional approach was adopted in four categories-therapeutic exercise, static and dynamic body biomechanics, awareness of proprioception, and maintenance of relaxed and balanced muscle tone. The patients were encouraged to perform daily activities rather than rest. RESULTS: Two patients with acute back pain gained complete relief without medication, modalities, equipment or other treatment one and two weeks after the first visit, respectively. Among the 30 chronic patients, after eight weeks of treatment, 12/30 (40%) gained complete relief from pain, 4/30 (13.3%) obtained more than 3/4 and less than complete relief, 7/30 (23.3%) had more than 1/2 and less than 3/4 relief, 2/30 (6.7%) gained less than 1/2 pain relief, 1/30 (3.3%) had no improvement, 1/30 (3.3%) deteriorated, and 3/30 (10%) were lost during surveillance. The patients reported no loss of work time attributed to back pain. Two acute patients visited the clinic four times and three times, respectively. The former received three prescriptions for an upper respiratory infection one month after complete remission of back pain, and the latter received no prescriptions for medication. On average, each chronic patient visited the clinic 4.83 times in 8 weeks. In only 25 of 145 (17.2%) visits was medication prescribed for other indications, and in 8 of 145 (5.5%) visits vitamin B complex or Alinamin-F for placebo was prescribed. We used neither modalities nor equipment. Only 7/30 (23.3%) patients received concurrent treatment from other medical institutions. Regarding compliance with the programmed exercise at home, two acute patients complied well. Among the 30 chronic patients, 22 (73.3%) had good compliance, 3 (10%) had poor compliance, 2 (6.7%) failed to comply and 3 (10%) were lost in follow up. CONCLUSIONS: Treating patients with back pain in primary care clinics with a functional approach by physicians appropriately trained in primary care was a good, efficacious, economic, and practical way, although neglected elsewhere. Further research and practice in our society might be worth while.

Adult↗
PubMed1993

[Socioeconomic incidences and prognostic factors of low back pain caused by occupational injuries among the hospital personnel of Grenoble University Hospital Center].

Low back pain is generally believed to be common among hospital employees. This cross-sectional, retrospective study was carried out to determine the annual incidence of low back pain ascribable to occupational injuries in hospital employees and to evaluate factors influencing the prognosis of these injuries. In 1989, 70 employees working at the Grenoble Teaching Hospital (GTH) reported an occupational injury responsible for low back pain. Each of these employees filled out an epidemiological questionnaire during a routine evaluation by a rheumatologist. Overall annual incidence of occupational injuries with subsequent low back pain was 1.9% among GTH employees. Higher incidences were seen among employees whose occupations involved patient transfer, as well as among nursing assistants. Activities associated with an increased risk of low back pain included handling of patients or objects and work requiring prolonged periods in uncomfortable positions or in the standing position. A previous history of low back disease and a longer period of time in the current work were also associated with an increased risk of low back pain. Characteristic clinical profiles of patients with low back pain subsequent to occupational injury were determined by occupation and type of hospital department. The analysis of long-duration absence from work and long-term consequences on career confirmed the significant adverse socioeconomic impact of these injuries.

Academic Medical Centers↗
PubMed1993

The association of mild-moderate isthmic lumbar spondylolisthesis and low back pain in middle-aged patients is weak and it only occurs in women.

This article reports on a cohort-like study of 20 women and 26 men with spondylolisthesis derived from a population of 1147 randomly selected 45-64-year-old subjects against sex-matched control subjects derived from the same source. Seventy-five percent of the spondylolisthetic subjects belonged to Meyerding class I representing mild slip. Low back symptoms during the previous day were more prevalent in women with spondylolisthesis than in control subjects (risk ratio was 7.0; 95% confidence interval 1.4-35.7), and the back pain index was higher (P = 0.028). No significant differences were seen between the groups of men in back symptoms. The use of healthcare facilities and the proportion of subjects receiving invalidity pension because of low back disease did not show any differences between the study groups of either sex. In subjects with spondylolisthesis the degree of vertebral body slip was associated with degeneration of the olisthetic intervertebral disc (P = 0.003), but it was not associated with increased occurrence of back symptoms or pain index. These data suggest that mild-moderate spondylolisthesis detected by chance in a middle-aged population does not predispose to more disabling back pain than back problems experienced by those without spondylolisthesis. However, women with spondylolisthesis have mild back symptoms more often than control subjects, suggesting that in clinical practice and future studies the sex of the patient should be considered in the evaluation of the importance of radiologic spondylolisthesis.

Cohort Studies↗
PubMed1997

Pain and health status of primary care patients with low back pain.

BACKGROUND: In addition to the pain caused by low back problems, suffering may also adversely affect other aspects of patients' lives. Since there is little knowledge about the suffering caused by low back pain, a prospective cohort study was undertaken to study pain intensity, perceived health, and daily functioning of consecutive patients with low back pain presenting in general practice. METHODS: During a period of 2 years, 15 general practitioners enlisted consecutive patients with both chronic and recent-onset low back pain in the study. From the initial visit, each patient was monitored for a period of 6 months prospectively. The follow-up consisted of questionnaires mailed every 4 weeks to determine the intensity of the pain, perceived health, and daily functioning. RESULTS: Of the 605 patients identified, 430 were included in the follow-up; 6 months after the initial visit, 167 patients were lost to follow-up. At baseline, the analyses did not reveal any important differences between acute, subacute, and chronic low back pain. Pain intensity, perceived health, and daily functioning in all patients tended to resolve over time. This tendency was strongest in patients with acute low back pain. The change in pain intensity was not strongly correlated with changes in perceived health and daily functioning. CONCLUSIONS: All aspects of suffering caused by low back pain tend to diminish and resolve over time. No evidence was found of a relationship between perceived health or daily functioning and the duration of the low back pain.

Activities of Daily Living↗
PubMed1997

Use of lumbar radiographs for the early diagnosis of low back pain. Proposed guidelines would increase utilization.

OBJECTIVE: The Agency for Health Care Policy and Research (AHCPR) has recently published guidelines for the management of patients with acute low back pain, which include recommendations for the use of lumbar radiographs, based on the identification of "red flags" for fractures, tumors, or infections. The purpose of this study was to evaluate the potential impact of these guidelines in patients with new episodes of low back pain seen in primary care settings. DESIGN: Retrospective cohort study. SETTING: Four family clinics (18 physicians) in Edmonton, Alberta. PATIENTS: The records of all patients seen in 1992 and 1993 with a new episode of low back pain were reviewed: 963 patients had a history of back pain of less than 3 months. OUTCOME MEASURES: Lumbar radiograph utilization at the initial low back pain visit. Charts were also reviewed to determine subsequent occurrence of spinal tumors, infection, or fractures that could be related to low back pain. RESULTS: One hundred twenty-seven (13%) of the 963 patients with acute low back pain had lumbar radiographs during their first visit, 68 (54%) with oblique views. If the AHCPR guidelines had been applied to this population, 426 (44%) of the patients would have undergone radiography, increasing current utilization by 238%. Eight of the 963 patients had a diagnosis of fracture or bone tumor during follow-up. The sensitivity of the guidelines to potentially detect these diseases was higher than the physicians' utilization patterns, but their specificity and positive predictive values were low. CONCLUSIONS: The implementation of the AHCPR guidelines for the initial use of radiographs in patients with low back pain may increase utilization and economic costs. A more restricted and cost-efficient set of guidelines should be proposed.

Alberta↗
PubMedDate not supplied

[Epidemiologic study on the prevalence of low back pain in health personnel exposed to manual handling tasks].

An epidemiological study on the prevalence rate of low back pain among health care workers exposed to manual handling tasks and physical work load was performed. A representative sample (n. 1053) of nursing staff working at the San Matteo Hospital in Pavia was studied using a questionnaire with the purpose of evaluating the prevalence rate of low back pain and related risk factors. 86.4% of the subjects admitted having suffered from back pain at some stage in their life and 71.0% complained of back pain in the 3 months prior to answering the questionnaire. Multivariate logistic regression analysis revealed a significant correlation between low back pain, female gender and specific nursing activities. A significant correlation was found between smoking (> 20 cigarettes per day) and the presence of low back pain, due to intervertebral disk pathology. A statistically significant difference (p < 0.0001) was found in the average degree of disability between healthy nurses (1.3), those with low back pain taking analgesic drugs (5.9) and nurses suffering from low back pain without taking drugs (3.8).

Adult↗
PubMed1995

Who carries passengers in the back of pickup trucks?

This study was designed to compare pickup truck drivers who carried passengers in the back with those who did not, with respect to driving behaviors, sociodemographic features, and issues related to use of the pickup truck. A computerized assisted telephone survey was conducted in Riverside County, California. One thousand ten motor vehicle drivers were interviewed with respect to demographics, restraint use, driving behaviors, and variables related to vehicle use. Thirty-six percent (364) of the households had a pickup truck driver. Pickup drivers were grouped into those who stated that they had carried occupants in the back (n = 119) and those who had not (n = 245). A higher proportion of 16- to 24-year-old and 35- to 44-year-old pickup truck drivers carried passengers in the back of pickup trucks. Those who carried occupants in the back were significantly more likely to be Hispanic, to be students, and to live in a household that included teenagers. They also had a larger mean household size. They were less likely to own the pickup and less likely to be the principal wage earners. They were more likely to report four high-risk driving behaviors. They also used the pickup truck for multiple purposes, i.e. recreation, work, school transportation, and daily transportation. In the multivariate analysis, the presence of teenagers in the household, three high-risk driving behaviors, and three indicators of pickup truck use were independently related to carrying passengers in the back of a pickup. Those who allowed passengers in the back were significantly less likely to agree with statements suggesting restriction of travel in the back. Finally, only 9% of the respondents who carried passengers in the back of a pickup reported that the pickup truck was the only vehicle available in the household.

Adolescent↗
PubMed1997

A literature review of low back disorder surveillance measures and risk factors.

OBJECTIVE: The goal of this literature review was to gain insight into low back disorder risk factors via a critical examination of the surveillance measures and analysis techniques employed in existing literature. DESIGN: Fifty-seven original articles were evaluated and categorized as a function of their surveillance measures. BACKGROUND: There have been a plethora of articles concerning the causes of low back disorder, yet no specific risk factors are consistently associated with the development of these disorders. It was hypothesized that different low back surveillance measures and variations in risk factor (dependent variable) measurements have led to the inconsistencies in the literature. METHODS: Five low back disorder surveillance measures and five risk factor categories were defined for this review. Each article was classified on several criteria including: surveillance measures, risk factors, statistical methods, population and type of study. Summary statistics were calculated for the percentage of positive findings as a function of surveillance measure and risk factor category. RESULTS: The most consistently defined surveillance measure was incidence of low back disorder, with 82% of those investigating it as claims from medical records or Occupational Safety and Health Administration records. The combination of surveillance measures and risk factor influenced the outcome of investigations. Ninety-one percent of the direct or video methods of measuring exposure risk factor influenced outcome. Psychosocial measures had positive findings in 70% of the studies examining lost time. Finally, statistical methodology was critical in the outcome of these investigations. CONCLUSIONS: The surveillance measure of incidence had more positive findings, with exposure risk factors and the surveillance measures indicating more advanced stages of low back disorder such as lost time had more positive findings with psychosocial risk factors. Thus, as low back disorders progress to disability, the psychosocial risk factors play a more prominent role. RELEVANCE: In order to prevent low back disorders we must first understand the plethora of epidemiological literature. This literature review provides new insight on the critical issues that have contributed to the results of previous research.

Journal Article↗
PubMed2002

Back-priming of the RCM1 leucocyte-reduction filter: consequences for filtration efficacy.

BACKGROUND AND OBJECTIVES: The RCM1 leucocyte-reduction filter has been incorporated into two types of blood-donation sets of which one uses back-priming of the leucocyte filter with SAG-M solution. In this study we have compared the leucocyte-reduction efficacy of the RCM1 filter with or without back priming with SAG-M solution. MATERIALS AND METHODS: This study was a retrospective analysis of quality control data of 3529 leucocyte-filtered red cell units. Of these, 1002 whole-blood units were collected in a donation set that was back-primed by letting the SAG-M solution in the final storage bag run backwards through the filter into the bag of concentrated red cells. The remaining 2527 units were collected in a donation set that required no back-priming. Postfiltration leucocyte concentration was assessed using flow cytometry. RESULTS: There was a significant trend towards lower leucocyte concentration in the units in which back-priming of the filter preceded filtration, as compared to units filtered without back-priming [chi2trend= 18.8, degrees of freedom (d.f.) = 1, P < 0.0005]. CONCLUSIONS: Back-priming of the RCM1 filter for red cells with SAG-M solution is superior to no back-priming with regard to leucocyte-reduction efficacy.

Blood Preservation↗
PubMed1998

Distribution of cortical activation during visuospatial n-back tasks as revealed by functional magnetic resonance imaging.

Human neuroimaging studies conducted during visuospatial working memory tasks have inconsistently detected activation in the prefrontal cortical areas depending presumably on the type of memory and control tasks employed. We used functional magnetic resonance imaging to study brain activation related to the performance of a visuospatial n-back task with different memory loads (0-back, 1-back and 2-back tasks). Comparison of the 2-back versus 0-back tasks revealed consistent, bilateral activation in the medial frontal gyrus (MFG), superior frontal sulcus and adjacent cortical tissue (SFS/SFG) in all subjects and in six out of seven subjects in the intraparietal sulcus (IPS). Activation was also detected in the inferior frontal gyrus, medially in the superior frontal gyrus, precentral gyrus, superior and inferior parietal lobuli, occipital visual association areas, anterior and posterior cingulate areas and in the insula. Comparison between the 1-back versus 0-back tasks revealed activation only in a few brain areas. Activation in the MFG, SFS/SFG and IPS appeared dependent on memory load. The results suggest that the performance of a visuospatial working memory task engages a network of distributed brain areas and that areas in the dorsal visual pathway are engaged in mnemonic processing of visuospatial information.

Adolescent↗
PubMed2001

Back-propagating action potentials mediate calcium signalling in dendrites of bitufted interneurons in layer 2/3 of rat somatosensory cortex.

1. Bitufted interneurons in layer 2/3 of the rat (P14) somatosensory cortex have elongated apical and basal dendritic arbors that can span the entire depth of the cortex. Simultaneous dendritic and somatic whole-cell voltage recordings combined with Ca2+ fluorescence measurements were made to quantify voltage and Ca2+ signalling in dendritic arbors of bitufted neurons. 2. Action potentials (APs) initiated close to the soma by brief current injection back-propagated into the apical and basal dendritic arbors and evoked a transient increase in volume-averaged dendritic Ca2+ concentration (Delta[Ca(2+)](i)) of about 140 nM peak amplitude per AP. The AP evoked Ca2+ signal decayed with a time constant of about 200 ms. 3. A relatively high endogenous Ca(2+) binding ratio of approximately 285 determines the comparatively small rise in [Ca(2+)](i) of bitufted cell dendrites evoked by a back-propagating AP. 4. The [Ca(2+)](i) transient evoked by back-propagating dendritic APs decreased with distance (< or = 50 microm) from the soma in some neurons. At distances greater than 50 microm transients did not show a spatial gradient between the proximal and distal dendritic branches. 5. During trains of APs the mean amplitude of the steady-state increase in dendritic [Ca(2+)](i) encoded the AP frequency linearly up to 40 Hz with a slope of 20 nM Hz(-1). 6. The results suggest that APs initiated in the axon of bitufted neurons back-propagate and 'copy' the pattern of the axon's electrical activity also to the dendritic arbor. The AP pattern is transduced into a transient rise of dendritic [Ca(2+)](i) which, presumably, can regulate the receptive properties of the dendritic arbor for synaptic input. 7. Bitufted interneurons in layer 2/3 of the rat (P14) somatosensory cortex have elongated apical and basal dendritic arbors that can span the entire depth of the cortex. Simultaneous dendritic and somatic whole-cell voltage recordings combined with Ca2+ fluorescence measurements were made to quantify voltage and Ca2+ signalling in dendritic arbors of bitufted neurons. 8. Action potentials (APs) initiated close to the soma by brief current injection back-propagated into the apical and basal dendritic arbors and evoked a transient increase in volume-averaged dendritic Ca2+ concentration (Delta[Ca(2+)](i)) of about 140 nM peak amplitude per AP. The AP evoked Ca2+ signal decayed with a time constant of about 200 ms. 9. A relatively high endogenous Ca2+ binding ratio of approximately 285 determines the comparatively small rise in [Ca(2+)](i) of bitufted cell dendrites evoked by a back-propagating AP. 10. The [Ca(2+)](i) transient evoked by back-propagating dendritic APs decreased with distance (< or = 50 microm) from the soma in some neurons. At distances greater than 50 microm transients did not show a spatial gradient between the proximal and distal dendritic branches. 11. During trains of APs the mean amplitude of the steady-state increase in dendritic [Ca(2+)](i) encoded the AP frequency linearly up to 40 Hz with a slope of 20 nM Hz(-1). 12. The results suggest that APs initiated in the axon of bitufted neurons back-propagate and also 'copy' the pattern of the axon's electrical activity to the dendritic arbor. The AP pattern is transduced into a transient rise of dendritic [Ca(2+)](i) which, presumably, can regulate the receptive properties of the dendritic arbor for synaptic input.

Action Potentials↗
PubMed1992

Participation of endothelium-derived nitric oxide but not prostacyclin in the gastric mucosal hyperaemia due to acid back-diffusion.

1. The possible participation of prostacyclin and nitric oxide (NO) in the gastric mucosal hyperaemic response to acid back-diffusion through a disrupted gastric mucosal barrier was examined. The experiments were carried out on anaesthetized rats in which acid back-diffusion was elicited by gastric perfusion with dilute ethanol in 0.15 M HCl and gastric mucosal blood flow (MBF) was measured by the hydrogen gas clearance technique. 2. Indomethacin (28 mumols kg-1, s.c.), an inhibitor of the formation of cyclo-oxygenase products including prostacyclin, failed to alter mean arterial blood pressure (MAP), basal MBF and the hyperaemic response to acid back-diffusion in urethane-anaesthetized rats. 3. NG-nitro-L-arginine methyl ester (L-NAME; 13 and 43 mumols kg-1, i.v.), an inhibitor of endothelium-derived NO formation, increased MAP in a dose-dependent manner. Whilst basal MBF in urethane-anaesthetized rats was not changed, the increase in MBF caused by gastric perfusion with dilute ethanol in acid was dose-dependently depressed by L-NAME. The loss of H+ ions from the gastric lumen, an indirect measure of acid back-diffusion, was significantly enhanced by 43 mumols kg-1 L-NAME. In contrast, D-NAME (13 and 43 mumols kg-1) was without effect on MAP, basal and stimulated MBF, and acid back-diffusion. 4. Unlike in urethane-anaesthetized rats, L-NAME led to a significant reduction of basal MBF in phenobarbitone-anaesthetized rats. MAP in the phenobarbitone-anaesthetized rats was significantly higher than in urethane-anaesthetized rats, and the hypertensive effect of L-NAME under phenobarbitone anaesthesia was significantly smaller than under urethane anaesthesia.5. The rise in MBF brought about by acid back-diffusion was blocked by L-NAME administered to phenobarbitone-anaesthetized rats. Infusion of L-arginine (120 pmol kg -1 min- ', i.v.) led to a partial, but significant, reversal of the effects of L-NAME on MAP and the hyperaemia due to acid back-diffusion.6. These findings indicate that endothelium-derived NO plays an important mediator role in the gastric mucosal vasodilatation caused by back-diffusion whilst vasodilator prostanoids such as prostacyclin are not involved.

Anesthesia↗
PubMed2005

Evidence-based medicine and the challenge of low back pain: where are we now?

Low back pain has long been described as a challenge for both primary care physicians and specialists. Management of low back pain has also been criticized as frequently arbitrary, inappropriate, or ineffective. Contributing factors have been an inadequate evidence base and a need for more rigorous appraisals of the available literature. Evidence-based medicine, an approach to clinical problem solving, is predicated on the premise that high-quality health care will result from practices consistent with the best evidence. In contrast to the traditional medical paradigm that placed a heavy reliance on expert opinion, authority, and unsystematic clinical observations, evidence-based medicine emphasizes the need for rigorous critical appraisals of the scientific literature to inform medical decision making. Evidence-based medicine places strong weight on the requirement for valid studies, particularly randomized controlled trials, to appropriately evaluate the effectiveness of health care interventions. Because of the rapidly increasing volume of medical literature, however, most clinicians are unable to keep up-to-date with all the new data. Two types of preprocessed evidence that can aid busy clinicians in medical decision making are systematic reviews and evidence-based clinical practice guidelines. Like primary studies, systematic reviews and clinical practice guidelines must adhere to high methodologic standards to reduce error and bias. As in other areas of medicine, the approach to the management of low back pain has been positively affected by the availability of more clinical trials and better use of critical appraisal techniques to evaluate and apply research findings. In addition to more rigorous primary studies, an increasing number of high-quality systematic reviews and evidence-based clinical practice guidelines for low back pain are also available. Although some research gaps and methodologic shortcomings persist, the richer evidence base has greatly improved our understanding of what does and does not work for low back pain. Despite these advances, the best available evidence often does not inform everyday clinical decisions for low back pain. Nonetheless, there is widespread agreement that adherence to evidence-based practice will help improve low back pain patient outcomes and reduce arbitrary variations in care. This article reviews basic principles of evidence-based medicine, discusses evidence-based medicine in the context of low back pain management, and summarizes some useful evidence-based medicine resources.

Journal Article↗
PubMed1988

Back-leak of pelvic urine to the bloodstream.

The aim of the present investigation was to measure the back-leak of pelvic urine to the blood circulation. In normopenic hydronephrotic, dehydrated hydronephrotic and dehydrated control kidneys the back-leak was estimated from a servocontrolled machine which regulated infused saline to keep a present pelvic pressure constant. The disappearance of fluid from the renal pelvis could be measured at different pressure levels, and a pressure-dependent outflow of fluid was found. From these measurements a back-leak conductance could be calculated which proved to be independent of pressure. In the lower pressure range (15-20 mmHg) there was a significantly lower conductance in the dehydrated controls compared with the dyhydrated hydronephrotic kidneys, while in the higher pressure range (25-30 mmHg) no difference was found. From electron microscopical studies the pyelorenal back-leak of fluid in both hydronephrotic and control animals seemed to be most pronounced in the fornix region, as documented by a heavy presence of horseradish peroxidase in the intracellular spaces there. Other experiments with radioactively labelled inulin, which was injected into the pelvic cavity, indicated that most of the back-leak occurred via the renal blood vessels and not through the lymphatic system. The importance of this back-leak was evident from the measurements of the total kidney glomerular filtration rate (GFR) at a slightly increased pelvic pressure, where some of the urine with radioactive tracer flows back to circulation. The back-leak of pelvic urine could also affect the concentration mechanism by removing diluted urine which had flowed over the renal papilla, and through water and urea diffusion increased papillary interstitial osmolarity.

Animals↗