Biomedical subjects

Achim Elfering

Publications and source records attributed to Achim Elfering.

17 recordsLinked to original sources

PubMed2006

Nonoperative treatment for adolescent idiopathic scoliosis: a 10- to 60-year follow-up with special reference to health-related quality of life.

STUDY DESIGN: Retrospective study on patients 10 to 60 years of age after nonoperative treatment for adolescent idiopathic scoliosis (AIS). OBJECTIVES: To investigate long-term outcome with regard to pain, disability, psychological disturbance, and health-related quality of life (HRQOL) in nonoperatively treated patients with AIS. SUMMARY OF BACKGROUND DATA: Only little is known on the long-term quality of life and disability in patients nonoperatively treated for AIS. A detailed knowledge of the nonoperative treatment results is important when advising patients for surgery. METHODS: A total of 135 nonoperatively treated AIS patients with a minimum follow-up of 10 years were included in this investigation, 121 of whom responded to a questionnaire containing questions on pain, disability (Oswestry Disability Index [ODI], Hannover Functional Ability Questionnaire [HFAQ], psychological general well-being [PGWB], and health-related quality of life [WHOQOLBREF]). Eighty-one patients participated in a clinical/radiologic follow-up examination. Nonoperative treatment consisted of bracing (n = 60), physiotherapy (n = 59), and electrical stimulation (n = 2). The overall follow-up rate was 89.6%. The mean age at follow-up was 38.0 years (range, 20-73 years.). RESULTS: In general, patients achieved a satisfactory outcome 10 to 60 years (mean, 23 years) after nonoperative treatment with regard to pain, disability, and HRQOL. The average curve at first diagnosis measured 29.5 degrees (range, 15 degrees -59 degrees ) for the thoracic spine, 21.3 degrees (range, 15 degrees -28 degrees ) for the thoracolumbar spine, and 26.8 degrees (10 degrees -44 degrees ) for the lumbar spine. Thirteen patients showed a substantial change in curve size (+/-10 degrees ) between first diagnosis and end of growth: 11 curves progressed more than 10 degrees showing an average increase of 19.0 degrees (range, 12 degrees -30 degrees ) and 2 patients presented with less severe curves at follow-up (-10 degrees and -13 degrees ). After end of growth, 7 patients showed a substantial average increase of 16.3 degrees (range, 10 degrees -31 degrees ). Five of eight patients with thoracic curves greater than 80 degrees had restrictive pulmonary disease. Patients with curves greater than 45 degrees reported significantly higher pain levels than those with smaller curves. Patients only showed a minimal absolute disability (Oswestry and HFAQ), and no significant correlation was found between curve size and curve type, respectively. Compared with a healthy control group that was matched for age and gender, no significant differences were found in terms of HRQOL as assessed by the WHOQOLBREF questionnaire. No significant differences in pain, disability, or HRQOL were found between patients with and without brace treatment. CONCLUSIONS: Although pain, disability, HRQOL, and psychological general well-being are quite satisfactory on an absolute level, curve size was found to be a significant predictor for pain in a long-term follow-up.

Adolescent↗

PubMed2006

Effect of aging and degeneration on disc volume and shape: A quantitative study in asymptomatic volunteers.

Debate continues on the effect of disc degeneration and aging on disc volume and shape. So far, no quantitative in vivo MRI data is available on the factors influencing disc volume and shape. The objective of this MRI study was to quantitatively investigate changes in disc height, volume, and shape as a result of aging and/or degeneration omitting pathologic (i.e., painful) disc alterations. Seventy asymptomatic volunteers (20-78 years) were investigated with sagittal T1- and T2-weighted MR-images encompassing the whole lumbar spine. Disc height was determined by the Dabbs method and the Farfan index. Disc volume was calculated by the Cavalieri method. For the disc shape the "disc convexity index" was calculated by the ratio of central disc height and mean anterior/posterior disc height. Disc height, disc volume, and the disc convexity index measurements were corrected for disc level and the individuals age, weight, height, and sex in a multilevel regression analysis. Multilevel regression analysis showed that disc volume was negatively influenced by disc degeneration (p < 0.001) and positively correlated with body height (p < 0.001) and age (p < 0.01). Mean disc height and the disc convexity index were negatively influenced by disc degeneration but not by gender, weight, and height. Disc height was positively correlated with age (p < 0.01). From the results of this study, it can be concluded that disc degeneration generally results in a decrease of disc height and volume as well as a less convex disc shape. In the absence of disc degeneration, however, age tends to result in an inverse relationship on disc height, volume, and shape.

Adult↗

PubMed2006

Fat content of lumbar paraspinal muscles in patients with chronic low back pain and in asymptomatic volunteers: quantification with MR spectroscopy.

PURPOSE: To prospectively evaluate the fat content of paraspinal muscles by using proton magnetic resonance (MR) spectroscopy in patients with chronic low back pain (LBP) and in asymptomatic volunteers matched with regard to age, sex, and body mass index. MATERIALS AND METHODS: The study was approved by the responsible institutional review board. Informed consent was obtained from each patient and each volunteer. Single-voxel proton MR spectroscopy was used to measure the fat content of the lumbar multifidus and longissimus muscles in 25 patients (13 women, 12 men; mean age, 40.5 years) with chronic LBP and in 25 matched asymptomatic volunteers (13 women, 12 men; mean age, 39.8 years). The fat content was also graded semiquantitatively (grades 0-4). The relationship between fat content and LBP duration, LBP intensity, and self-rated disability was assessed (Pearson correlation). RESULTS: The mean percentage fat content of the multifidus muscle was 23.6% (95% confidence interval [CI]: 17.5%, 29.7%) in patients with chronic LBP and 14.5% (95% CI: 10.8%, 18.3%) in the volunteers (P = .014). The corresponding values for the longissimus muscle were 29.3% (95% CI: 23.4%, 35.3%) in patients with LBP and 26.0% (95% CI: 21.9%, 30.0%) in the volunteers (P = .66). The semiquantitative grading of the fat content of the multifidus muscle was 0 in 12 (48%) of 25 patients and in 14 (56%) of 25 volunteers, 1 in 11 (44%) patients and in eight (32%) volunteers, and 2 in two (8%) patients and three (12%) volunteers. The semiquantitative grading of the fat content of the longissimus muscle was 0 in nine (36%) of 25 patients and 15 (60%) of 25 volunteers, 1 in 13 (52%) patients and nine (36%) volunteers, and 2 in three (12%) patients and one (4%) volunteer. Neither grade 3 nor grade 4 was assigned to any muscle. The grading differences were not significant between patients and volunteers. No significant correlation was found between fat content and pain intensity, pain duration, or self-rated disability. CONCLUSION: Proton MR spectroscopy demonstrates a significantly higher fat content in the multifidus muscle in patients with chronic LBP than in asymptomatic volunteers. No difference was detected with a semiquantitative grading system.

Adipose Tissue↗

PubMed2006

Therapeutic efficacy of facet joint blocks.

OBJECTIVE: The objective of our study was to investigate outcome predictors of short- and medium-term therapeutic efficacy of facet joint blocks. MATERIALS AND METHODS: Forty-two patients with chronic lower back pain who were undergoing facet joint blocks at one (n = 29) or two (n = 13) levels were analyzed. All patients underwent MRI or CT of the lumbar spine within 5 months before the facet joint blocks. The facet joint blocks were performed under fluoroscopic guidance. A small amount (< 0.3 mL) of iodinated contrast agent, 0.5 mL of local anesthetics and 0.5 mL of steroids, were injected. The initial pain response was prospectively assessed using a visual analogue scale. Additional data, including short-term effect (> 1 week) and medium-term effect (> 3 months), were collected by a structured telephone interview. CT and MRI were reviewed with regard to the extent of facet joint abnormalities. Multiple logistic regression analyses were conducted to identify outcome predictor for efficacy of facet joint blocks. RESULTS: A positive immediate effect was seen in 31 patients (74%). A positive medium-term effect was found in 14 patients (33%). Pain alleviated by motion (p = 0.035) and the absence of joint-blocking sensation (p = 0.042) predicted pain relief. However, the extent of facet joint osteoarthritis on MRI and CT was not a significant predictor for outcome (p = 0.57-0.95). CONCLUSION: Facet joint blocks appear to have a beneficial medium-term effect in one third of patients with chronic lower back pain and may therefore be a reasonable adjunct to nonoperative treatment. However, outcome appears to depend on clinical, not on morphologic, imaging findings.

Adult↗

PubMed2005

Pain assessment.

Pain usually is the major complaint of patients with problems of the back, thus making pain evaluation a fundamental requisite in the outcome assessment in spinal surgery. Pain intensity, pain-related disability, pain duration and pain affect are the aspects that define pain and its effects. For each of these aspects, different assessment instruments exist and are discussed in terms of advantages and disadvantages. Risk factors for the development of chronic pain have been a major topic in pain research in the past two decades. Now, it has been realised that psychological and psychosocial factors may substantially influence pain perception in patients with chronic pain and thus may influence the surgical outcome. With this background, pain acceptance, pain tolerance and pain-related anxiety as factors influencing coping strategies are discussed. Finally, a recommendation for a minimum as well as for a more comprehensive pain assessment is given.

Adaptation, Psychological↗

PubMed2005

Predictors of surgical outcome and their assessment.

The relatively high rate of failed back surgery has prompted the search for "risk factors" to predict the result of spinal surgery in a given individual. However, the literature reveals few unequivocal predictors and they often explain a relatively low proportion of variance in outcome. This suggests that we have a long way to go before being able to rest easily, having refused someone surgery on the basis of unfavourable baseline characteristics. The best recommendation is to ensure, firstly, that the indication for surgery is absolutely clear-cut (i.e. that surgically remediable pathology exists) and then to consider the various factors that may influence the "typical" outcome. Consistent risk factors for a poor outcome regarding return-to-work include long-term sick leave/receipt of disability benefit. Hence, every effort should be made to keep the individual in the workforce, despite the ongoing symptoms and plans for surgery. In patients with a particularly heavy job, consultation with occupational physicians might later ease the patient's way back into the workplace. Patients with degenerative disorders and/or comorbidity should be counselled that few of them will have complete/lasting pain relief or a complete return to pre-morbid function. Patients with a high level of distress may benefit from psychological treatment, before and/or accompanying the surgical treatment. The opportunity (time), encouragement (education and positive messages), and resources (referral to appropriate support services) to modify risk factors that are indeed modifiable should be offered, and realistic expectations should be discussed with the patient before the decision to operate is made.

Employment↗

PubMed2005

Work-related outcome assessment instruments.

Prevention of work disability is a primary goal within treatment of spinal disorders. Work-related outcome measures therefore are essential indices within evidence-based medicine. So far many measures suffer, however, from standardized measurement, standardized terminology, and a lack of theoretical background. This review addresses traditional indicators like work status and sickness absence, and discusses more theory-bound concepts, i.e. work ability, occupational risk factors for recurrence of symptoms and re-injury, work-related attitudes that may become obstacles to recovery, and individual reactions to occupational stressors that increase the risk of maintenance and recurrence of symptoms. The review includes methodological and theoretical considerations and recommendations for the use of work-related outcome measures in future outcome research.

Employment↗

PubMed2005

Outcome assessment in low back pain: how low can you go?

The present study examined the psychometric characteristics of a "core-set" of six individual questions (on pain, function, symptom-specific well-being, work disability, social disability and satisfaction) for use in low back pain (LBP) outcome assessment. A questionnaire booklet was administered to 277 German-speaking LBP patients with a range of common diagnoses, before and 6 months after surgical (N=187) or conservative (N=90) treatment. The core-set items were embedded in the booklet alongside validated 'reference' questionnaires: Likert scales for back/leg pain; Roland and Morris disability scale; WHO Quality of Life scale; Psychological General Well-Being Index. A further 45 patients with chronic LBP completed the booklet twice in 1-2 weeks. The minimal reliability (similar to Cronbach's alpha) for each core item was 0.42-0.78, increasing to 0.84 for a composite index score comprising all items plus an additional question on general well-being ('quality of life'). Floor or ceiling effects of 20-50% were observed for some items before surgery (function, symptom-specific well-being) and some items after it (disability, function). The intraclass correlation coefficient (ICC) ("test-retest reliability") was moderate to excellent (ICC, 0.67-0.95) for the individual core items and excellent (ICC, 0.91) for the composite index score. With the exception of "symptom-specific well-being", the correlations between each core item and its corresponding reference questionnaire ("validity") were between 0.61 and 0.79. Both the composite index and the individual items differentiated (P<0.001) between the severity of the back problem in surgical and conservative patients (validity). The composite index score had an effect size (sensitivity to change) of 0.95, which was larger than most of the reference questionnaires (0.47-1.01); for individual core items, the effect sizes were 0.52-0.87. The core items provide a simple, practical, reliable, valid and sensitive assessment of outcome in LBP patients. We recommend the widespread and consistent use of the core-set items and their composite score index to promote standardisation of outcome measurements in clinical trials, multicentre studies, routine quality management and surgical registry systems.

Adolescent↗

PubMed2005

Working conditions and three types of well-being: a longitudinal study with self-report and rating data.

The mean of self-report and observer ratings of working conditions was used to predict 3 types of well-being in 52 young workers: general well-being, job-related well-being, and spillover from work to nonwork domains. Longitudinally, job control predicted spillover. There was no strong evidence for reverse causation. Synchronously, Time 2 job stressors predicted all types of well-being, and job control predicted general well-being. Because dependent variables at Time 1 are controlled for, this indicates short-term effects. Results for stressors are in line with a stress reaction model, indicating a rather quick symptom development but reversibility. The effect of control on spillover, however, suggests a sleeper effect model, with symptoms appearing with delay.

Adult↗

PubMed2005

Human factors in matching images to standards: assimilation and time order error.

OBJECTIVES: This study examines recognition performance to depend on image context and time order error. Recognition of standard images is a basic process in medical image analysis. METHODS: After the presentation of a standard square, 20 subjects identified the standard within a variety of 7 squares. The choice was between the standard and either 3 smaller and 3 larger squares, 5 smaller and 1 larger square, or 5 larger and 1 smaller square (context conditions). RESULTS: Multilevel regression analysis showed large individual differences in judgments (P < .001). Context induced assimilation of judgments to the medium-sized square within response options (P < .001). Negative time order error in rapid judgments caused an underestimation of the standard (P < .001). CONCLUSIONS: Assimilation of judgments and time order error might be a threat to the reliability of medical image analysis. Some procedural recommendations are derived to reduce bias and increase patient safety in radiology.

Adult↗

PubMed2005

Lumbar disk herniation: do MR imaging findings predict recurrence after surgical diskectomy?

PURPOSE: To retrospectively evaluate if the degree of disk degeneration and disk herniation volume at magnetic resonance (MR) imaging are risk factors for recurrent disk herniation. MATERIALS AND METHODS: The institutional review board permits such retrospective studies, and individual informed consent was not required. MR imaging findings obtained before initial diskectomy in 30 patients (mean age, 42.8 years; 10 women, 20 men) with recurrent disk herniation (study group) and 30 patients (mean age, 42.2 years; nine women, 21 men) without recurrence for at least 2 years after surgery (control group) were compared. Disk degeneration was assessed on T2-weighted sagittal MR images with a five-point grading system (grade I indicated no degeneration; grade II, horizontal hypointense bands within disk; grade III, inhomogeneous disk with intermediate signal intensity; grade IV, no distinction between inner and outer parts of disk; and grade V, collapsed hypointense disk). Disk herniation was classified as representing protrusion, extrusion, or sequestration. The volume of both the affected intervertebral disk and the herniated disk material was measured. Qualitative and quantitative analyses were performed by two readers. The chi(2) test was used for comparison of categorical variables. For comparison of disk degeneration and volumes between patients with and those without recurrence, a paired two-tailed t test was used. Odds ratios based on the extent of disk degeneration were calculated for the entire sample. RESULTS: Advanced disk degeneration (grades IV and V) was significantly less frequent in the study group than in the control group (P < .006). The risk of recurrent disk herniation decreased by a factor of 3.4 for each increase in grade of disk degeneration (odds ratio: 3.58; 95% confidence interval: 1.3, 9.6; P = .011). Mean disk herniation volume as a percentage of intervertebral disk volume was 10.59% +/- 3.41 in the study group and 11.56% +/- 3.84 in the control group. This difference was not significant (P = .31). CONCLUSION: Minor disk degeneration but not herniation volume represents a risk factor for the recurrence of disk herniation after diskectomy.

Adult↗

PubMed2004

Longitudinal validation of the fear-avoidance beliefs questionnaire (FABQ) in a Swiss-German sample of low back pain patients.

Work and activity-specific fear-avoidance beliefs have been identified as important predictor variables in relation to the development of, and treatment outcome for, chronic low back pain. The objective of this study was to provide a cross-cultural German adaptation of the Fear-Avoidance Beliefs Questionnaire (FABQ) and to investigate its psychometric properties (reliability, validity) and predictive power in a sample of Swiss-German low back pain patients. Questionnaires from 388 operatively and non-operatively treated patients were administered before and 6 months after treatment to assess: socio-demographic data, disability (Roland and Morris), pain severity, fear-avoidance beliefs, depression (ZUNG) and heightened somatic awareness (MSPQ). Complete baseline and follow-up questionnaires were available from 255 participants. The corrected item-total correlations, coefficients of test-retest reliability and internal consistencies of the two scales of the questionnaire were highly satisfactory. In a confirmatory factor analysis (CFA), all items loaded on the appropriate factor with minor loadings on the other. Cross-sectional regression analysis with disability and work loss as the dependent variables yielded results that were highly comparable with those reported for the original version. Prognostic regression analysis replicated the findings for work loss. The cross-cultural German adaptation of the FABQ was very successful and yielded psychometric properties and predictive power of the scales similar to the original version. The inclusion of fear-avoidance beliefs as predictor variables in studies of low back pain is highly recommended, as they appear to have unique predictive power in analyses of disability and work loss.

Adolescent↗

PubMed2002

The significance of spinal canal dimensions in discriminating symptomatic from asymptomatic disc herniations.

Spinal canal dimensions are assumed to play a significant role with regard to the development of symptoms in individuals with disc herniations. The literature is inconclusive on the significance of spinal canal size as a risk factor for sciatica, mainly because of study design problems. The objective of this study, therefore, was to test the hypothesis that spinal canal dimensions are a significant risk factor for the development of sciatica, comparing symptomatic and asymptomatic individuals. Thirty symptomatic patients undergoing lumbar discectomy and 45 asymptomatic volunteers were investigated by clinical and MRI examination. The size of the spinal canal and thecal sac as well as the midsagittal spinal canal diameter were measured using a point counting method and scanner software, respectively. Differences between the groups were compared separately for each level L3/4 to L5/S1. The intra- and inter-observer error ranged between 0.95 and 0.99 for all measurements. In symptomatic patients, the dimensions of the spinal canal and thecal sac as well as the midsagittal spinal canal diameter were smaller at all disc levels. Unpaired t-test demonstrated a significant difference, ranging from P<0.05 to P<0.001. When controlled for age, sex and body height, the odds ratio for a symptomatic disc herniation increased to as high as 35, depending on the spinal level, when the size of the spinal canal was smaller than the mean for controls by two standard deviations or more. In symptomatic patients, spinal canal dimensions are significantly smaller than those in asymptomatic individuals. Spinal canal dimension is an important factor discriminating patients from control subjects. A clinically relevant grading system for disc herniation should therefore be based on the spatial relationship between herniated disc material and neurogenic structures.

Adult↗

PubMed2002

Risk factors for lumbar disc degeneration: a 5-year prospective MRI study in asymptomatic individuals.

STUDY DESIGN: A longitudinal magnetic resonance imaging investigation of lumbar disc degeneration in asymptomatic individuals was conducted. OBJECTIVE: To investigate risk factors for the development or deterioration of lumbar disc degeneration. SUMMARY OF BACKGROUND DATA: Numerous studies have explored the significance of certain risk factors for the development or progression of disc degeneration, but no comprehensive longitudinal magnetic resonance imaging-based study has been reported that simultaneously considers clinical, morphologic, physical, psychosocial, and occupational risk factors. METHODS: In the 5-year follow-up evaluation of 41 asymptomatic individuals, the risk factors for the development of lumbar disc degeneration and its progression were investigated. All 41 individuals had a magnetic resonance imaging scan at baseline and at the minimum 5-year follow-up assessment using the same scanner and protocol. The magnetic resonance images were analyzed independently by two radiologists with regard to disc degeneration. Various predictor variables were assessed both at baseline and follow-up, with special emphasis on physical job characteristics, sports activities, and magnetic resonance image-based morphologic findings. RESULTS: Of the 41 individuals, 17 (41%) exhibited a deterioration of the disc status. In 10 individuals, the progression of disc degeneration was one grade or more. Only a weak correlation existed between progressive disc degeneration and low back pain development during a 5-year follow-up period. Multiple logistic regression analysis demonstrated that the extent of disc herniation (odds ratio [OR], 12.63; confidence interval [CI], 1.24-128.49), the lack of sports activities (OR, 2.71; CI, 1.04-7.07), and night shift work (OR, 23.01; CI, 1.26-421.31) were significant predictors for disc degeneration during follow-up evaluation when control was used for the number of degenerated discs at baseline, gender, age, and body mass index. CONCLUSIONS: The results indicate that the extent of disc herniation, the lack of sports activities, and night shift work are significant risk factors for the development of lumbar disc degeneration and its progression.

Adult↗

PubMed2002

Supportive colleague, unsupportive supervisor: the role of provider-specific constellations of social support at work in the development of low back pain.

In a 5-year longitudinal study, social support was investigated as a predictor of low back pain (LBP) in 46 initially asymptomatic individuals. Distinguishing between colleagues in general and the colleague one feels closest to, the authors analyzed constellations of support from supervisor (which had positive effects) and closest colleague (which had detrimental effects). Configural frequency analysis yielded a type characterized by high support from one's closest colleague and low support from one's supervisor at Time 1 and more LBP and disability at Time 2. Controlling for negative affectivity did not change findings. Results are interpreted in terms of being dependent on that one source of support in an unsupportive environment, which creates feelings of dependence, incompetence, and reciprocity obligations.

Humans↗

PubMed2002

Time control, catecholamines and back pain among young nurses.

OBJECTIVES: This study had two objectives. First, it addressed concern with the contribution of work stressors and resources to the development of back pain, over and above the influence of biomechanical work factors. Second, using recent models about the role of the sympathetic-adrenal medullar system in musculoskeletal problems as its basis, it tested whether low-back pain is associated with higher levels of catecholamines. METHODS: Altogether 114 nurses filled out a questionnaire in their first year of practice and again one year later. In addition, in a subsample of 24 nurses studied intensively at follow-up, urinary catecholamines were assessed at noon, before the end of work, in the evening, and at corresponding times on a day off. Daily stressful experiences and daily mood were also recorded. RESULTS: With control for baseline pain, biomechanical workload, and other potentially confounding variables, time control at the beginning of the study predicted low-back pain a year later. In the subsample, the epinephrine and norepinephrine levels were higher in those reporting more frequent episodes of back pain, the largest differences occurring at the end of work. In addition, control over stressful events at work was lower in this group. CONCLUSIONS: Time control is a risk factor for low-back pain among nurses beyond the influence of physical work load. Low control at work may increase the activity of the sympathetic-adrenal medullar system, which seems to play an important role in the development of musculoskeletal pain.

Adult↗

PubMedDate not supplied

Two urinary catecholamine measurement indices for applied stress research: effects of time and temperature until freezing.

Research on stress at work often involves the analysis of urinary adrenaline and noradrenaline. It is usually assumed that samples have to be cooled quickly and stored at refrigerator temperature before freezing. This is often difficult to achieve in field studies. This experimental study therefore tests the robustness of results when samples are not cooled immediately. Samples of 9 men and women, collected at 3 points in time, were immediately frozen, kept for a variable delay in a warm room, or stored in a refrigerator before freezing. Two indices were calculated: (a) the ratio of hormones to liquid volume, period of excretion, and body weight; and (b) the ratio of hormones to urinary creatinine. The reliability of high performance liquid chromatography analysis was satisfactory, as was the comparability of the 2 indices. Unfavorable storage up to 24 hr did not cause bacteria-driven decreases of catecholamines, regardless of storage temperature or sampling time. Results suggest high stability for at least 24 hr without cooling, provided the samples are immediately acidified. Cooling may therefore be handled less restrictively than has been assumed. The application of this research is to facilitate research in settings where samples are collected at different places, such as participants' homes or different workplaces.

Adult↗