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PubMed2004

Systematic review of early recurrent stenosis after carotid angioplasty and stenting.

BACKGROUND AND PURPOSE: Carotid angioplasty and stenting (CAS) has emerged as a potential alternative to endarterectomy (CEA) for the treatment of carotid artery disease. Aside from the periprocedural complication rates, the benefits of CAS will be affected by the incidence of recurrent carotid stenosis. METHODS: We conducted a systematic analysis of all peer-reviewed studies reporting on the rate of restenosis (> or =50%) after CAS based on duplex ultrasound or angiography that were published between January 1990 and July 2004. We identified 34 studies that reported on a total of 4185 patients with a follow-up of 3814 arteries over a median of 13 months (range, 6 to 31 months). The ultrasound criteria and the lower thresholds for defining a recurrent stenosis were very heterogeneous. RESULTS: The cumulative restenosis rates after 1 and 2 years were approximately 6% and 7.5% in those studies, which used a lower restenosis threshold > or =50% to 70% and approximately 4% in the first 2 years after CAS in those studies, which used a lower restenosis threshold >70% to 80%. CONCLUSIONS: In reviewing the current literature, the early restenosis rates after CAS compare well with those reported for CEA. However, this analysis of the peer-reviewed literature also indicates that the early restenosis rates after CAS might be higher than previously suggested in observational surveys. Therefore, an active follow-up of all stented arteries seems to be warranted. Moreover, the bulk of endovascular data are derived from small studies with short follow-up periods so that the long-term durability of CAS still needs to be established in large trials. Ideally, these studies should use a clear and uniform definition of restenosis and identical follow-up schedules.

Aged↗
PubMed2005

Parallel solid-phase synthesis of mucin-like glycopeptides.

The glycopeptide, Ac-Pro-Thr(alpha-D-GalNAc)-Thr(alpha-D-GalNAc)-Thr(alpha-d-GalNAc)-Pro-Leu-Lys-NH(2) (1), which features three consecutive O-glycosylated Thr residues and mimics a portion of mucin 2, has been prepared by solid-phase synthesis. Seven related, partially glycosylated peptides (2-8) were synthesized as well. This suite of molecules allowed a systematic analysis of synthetic protocols. N(alpha)-(9-Fluorenylmethoxycarbonyl)-O-(3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha-D-galactopyranosyl)-L-threonine pentafluorophenyl ester [Fmoc-L-Thr(Ac(3)-alpha-D-GalN(3))-OPfp] was used as a building block that coupled efficiently when used in a relatively low molar excess, that is, approximately 1.5 equiv, with N,N-dimethylformamide (DMF) as the solvent. For conversion of the azido group to the N-acetyl function, direct treatment with thioacetic acid was preferred over a two-step procedure involving reduction with dithiothreitol (DTT) followed by N-acetylation. Effective O-deacetylation of 1-8 in solution was achieved by treatment with sodium methoxide (10-15 mM; approximately 5 equiv) in methanol. On-resin deacetylation techniques were also examined, using sodium methoxide (6-10 mM) in DMF-methanol (17:3) (for 4 and 11) or hydrazine (70 mM) in methanol (for 8). The more convenient on-resin technique in DMF-methanol gave yields similar to solution conditions, and promises to be widely useful for solid-phase glycopeptide synthesis. HPLC profiles showed that free glycopeptides elute earlier than the corresponding O-acetylated derivatives, and that retention times vary systematically with the number of sugar moieties. (1)H NMR studies carried out in water showed an increase in conformational organization of glycopeptides with increased density of glycosylation.

Amino Acid Sequence↗
PubMed1980

An analysis of femoral component stem design in total hip arthroplasty.

UNLABELLED: A comparative study of the various aspects of the design of the femoral components of total hip replacements was done using three-dimensional finite-element stress analysis. The aspects of deisgn that were considered included: length, cross-sectional size, and material properties of the stem; presence or absence of a medial collar; and material properties of the cement. We found that increasing the length of the stem generally increased the stress present in the stem while decreasing the stress present in the cement. Increasing the cross-sectional size of the stem decreased the stress in both the stem and the cement. Decreasing the modulus of elasticity of the stem material decreased the stress in the stem but increased the stress in the cement. Increasing the modulus of elasticity of the cement decreased the stress in the stem and increased the stress in the cement. Contact of the collar of a femoral prosthesis with the calcar femorale increased the longitudinal component of stress within the region of the calcar femorale. CLINICAL RELEVANCE: The mechanical longevity of a total joint reconstruction is related to the stress distribution throughout the prosthesis, cement, and bone. The stress distribution is related to a number of factors, including the design of the prosthetic components (for example, stem size, stem length, stem modulus of elasticity, and cement modulus of elasticity). Reducing the stresses in prosthetic components to minimize the risk of failure can be accomplished only through systematic analysis of all components of the reconstruction.

Bone Cements↗
PubMed2003

The efficacy of stretching for prevention of exercise-related injury: a systematic review of the literature.

The objective of this study was to conduct a systematic analysis of the literature to assess the efficacy of stretching for prevention of exercise-related injury. Randomized clinical trials (RCTs) and controlled clinical trials (CCTs) investigating stretching as an injury prevention measure were selected. A computer-aided search of the literature was conducted for relevant articles, followed by assessment of the methods of the studies. The main outcome measures were scores for methodological quality based on four main categories (study population, interventions, measurement of effect, and data presentation and analysis) and main conclusions of authors with regard to stretching. One RCT (25%) and three CCTs (100%) concluded that stretching reduced the incidence of exercise-related injury. Three RCTs (75%) concluded that stretching did not reduce the incidence of exercise-related injury. Only two studies scored more than 50 points (maximum score=100 points) indicating that most of the studies selected were of poor quality. Neither of the two highest scoring RCTs showed positive effects for stretching. Due to the paucity, heterogeneity and poor quality of the available studies no definitive conclusions can be drawn as to the value of stretching for reducing the risk of exercise-related injury.

Athletic Injuries↗
PubMed2003

Welsh women's comments about breast problems and the care given: a qualitative study in the community.

The aim of this study was to undertake a systematic analysis, using qualitative software, of the free text comments from a postal survey exploring women's experiences of breast symptoms, their expectations of treatment, knowledge of breast cancer risk factors and perceptions of risk, in 34 group general practices in South Wales. The 959 women who returned the questionnaire, out of 1126 (response rate 85%), comprised 497 women who consulted their general practitioner (GP) with a new breast symptom during the baseline data collection period and 462 controls who had not. When the survey was conducted the researchers did not know whether these women had cancer or had previously been treated for it. One-third (33.1%) of those returning the survey (n = 318) wrote comments. Compared to the rest, they were significantly more likely to have consulted their GP for a new breast symptom and to have stayed on at school and/or gone on to more education or training. The majority wrote about their own experience of breast symptoms and/or the care received in primary and secondary settings. The general tone was factual and when evaluation took place positive comments were more frequent than negative ones. Nothing suggested that the respondents had been upset or made more anxious by the preceding questions on such a potentially sensitive topic. Free text comments gathered in surveys can provide valuable data if systematically analysed. Doctors, particularly GPs, can be reassured that more women in this community sample who expressed an opinion on care were positive. The negative comments, however, highlight issues that still need to be addressed in therapeutic relationships.

Adolescent↗
PubMed1997

The nature and extent of body-image disturbances in anorexia nervosa and bulimia nervosa: a meta-analysis.

OBJECTIVE: Although body-image disturbance is among the diagnostic criteria for anorexia nervosa and bulimia nervosa, the nature and extent of this disturbance have not been precisely identified. This is the purpose of this first meta-analysis of extant research on body image and eating disorders. METHOD: Using contemporary techniques, the meta-analysis systematically examined 66 studies (from 1974 to 1993) of perceptual and attitudinal parameters of body image among anorexics and bulimics relative to control groups. RESULTS: Attitudinal body dissatisfaction, both questionnaire and self-ideal discrepancy measures, produced substantially larger effect sizes than did perceptual size-estimation inaccuracy. Body dissatisfaction measures, whether global or weight/shape related, differentiated bulimic and anorexic groups (with bulimics having more dissatisfaction), whereas perceptual distortion indices did not. Somewhat larger effects occurred with whole-body than with body-part size-estimation assessments. Size distortion among patients with eating disorders appears unlikely to reflect a more generalized sensory/perceptual deficit. DISCUSSION: Scientific, conceptual, and clinical implications of these findings are delineated.

Anorexia Nervosa↗
PubMed2006

Trends in national and state-level obesity in the USA after correction for self-report bias: analysis of health surveys.

OBJECTIVES: To quantify population-level bias in self-reported weight and height as a function of age, sex, and the mode of self-report, and to estimate unbiased trends in national and state level obesity in the USA. DESIGN: Statistical analysis of repeated cross-sectional health examination surveys (the National Health and Nutrition Examination Survey [NHANES]) and health surveys (the Behavioral Risk Factor Surveillance System [BRFSS]) in the USA. SETTING: The 50 states of the USA and the District of Columbia. RESULTS: In the USA, on average, women underreported their weight, but men did not. Young and middle-aged (<65 years) adult men over-reported their height more than women of the same age. In older age groups, over-reporting of height was similar in men and women. Population-level bias in self-reported weight was larger in telephone interviews (BRFSS) than in-person interviews (NHANES). Except in older adults, height was over-reported more often in telephone interviews than in-person interviews. Using corrected weight and height in the year 2000, Mississippi (30%) and Texas (31%) [corrected] had the highest prevalence of obesity for men; Texas (37%), Louisiana (37%), Mississippi (37%), District of Columbia (37%), Alabama (37%), and South Carolina (36%) for women. CONCLUSIONS: Population-level bias in self-reported weight and height is larger in telephone interviews than in-person interviews. Telephone interviews are a low-cost method for regular, nationally- and sub-nationally representative monitoring of obesity. It is possible to obtain corrected estimates of trends and geographical distributions of obesity from telephone interviews by using systematic analysis which measure weight and height from an independent sample of the same population.

Adult↗
PubMed2006

Using local microbiologic data to develop institution-specific guidelines for the treatment of hospital-acquired pneumonia.

BACKGROUND: While current guidelines recommend consideration of local microbiologic data when selecting empiric treatment for hospital-acquired pneumonia (HAP), few specifics of how to do this have been offered. METHODS: We conducted a retrospective analysis of HAP pathogens in 111 consecutive patients who acquired HAP during July to December 2004 and had a corresponding positive culture finding for a bacterial pathogen. These data were used to develop institution-specific guidelines. RESULTS: The most common bacteria identified were Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa, which were associated with 38%, 25%, and 19% of pneumonias, respectively. Susceptibility of Gram-negative bacteria to piperacillin-tazobactam and cefepime was 80% and 81%, respectively. The isolation of organisms resistant to piperacillin-tazobactam or cefepime was significantly more frequent in patients who had been hospitalized > or = 10 days. Of Gram-negative isolates resistant to piperacillin-tazobactam or cefepime, ciprofloxacin was active against < 10%, while amikacin was active against > 80%. New treatment guidelines were developed that divided the American Thoracic Society/Infectious Diseases Society of America "late onset/risk of multidrug-resistant pathogens" group of patients into two subcategories: "early-late" pneumonias (< 10 days of hospitalization) and "late-late" pneumonias (> or = 10 days of hospitalization). Guideline-directed treatment regimens would be predicted to provide adequate initial therapy for > 90% of late-onset pneumonias at our institution. CONCLUSIONS: Current guidelines suggest adding either an aminoglycoside or a fluoroquinolone to beta-lactam therapy for empiric Gram-negative coverage. However, in our institution, adding ciprofloxacin would not appreciably enhance the likelihood of providing initial appropriate antibiotic coverage. This underscores the importance of employing a systematic analysis of local data when developing treatment guidelines.

Anti-Bacterial Agents↗
PubMed1983

Systematic management and analysis of fatty acid data from multiple tissue samples.

A systematic approach has been developed for the collection and analysis of gas chromatographic (GC) data from multiple fatty acid profiles. The approach was applied to a series of polar and nonpolar tissue lipids generated in animal feeding studies to allow a comparison of mean fatty acid profiles as a function of either dietary regimen or tissue location. The magnitude of the studies, sufficiently large to minimize error from animal variabilities, mandated the use of computer assistance. Nevertheless, manual input was essential due to the complexity of the GC patterns, and was invoked for peak assignment and report editing. The approach discussed here allowed for the consolidation and statistical analysis of data from over 30,000 GC peaks, and generated results in both tabular and graphic formats. It should be extendable to other chromatographic studies of lipid components.

Adipose Tissue↗
PubMed1999

Clinical performance of CEREC ceramic inlays: a systematic review.

OBJECTIVE: This systematic review of clinical trials seeks to identify the clinical performance of intra-coronal CEREC restorations luted with an adhesive composite technique. The focus of the review is to establish the survival rate of these restorations and to identify the factors that may cause them to fail. METHOD: A comprehensive literature search was undertaken, spanning from the year of introduction of the technology--1986 to 1997. This review identifies universal indicators of the clinical performance of intra-coronal CEREC restorations luted with an adhesive composite technique. Throughout the critical appraisal, each individual study was analysed identifying the aims, the methodology and materials used and the results obtained. RESULTS: 29 clinical reports were identified in the search. The systematic analysis reduced the focus of review to 15 studies. The data available establishes ceramic intra-coronal restorations machined by the CEREC system as a clinically successful restorative method with a mean survival rate of 97.4% over a period of 4.2 years. The review also highlights the reasons and the rates of failure for this type of restoration. The predominant reasons for failures are fracture of the ceramic, fracture of the supporting tooth, postoperative hypersensitivity and wear of the interface lute. SIGNIFICANCE: Machinable ceramics, as used by the CEREC system provide a useful restoration with a high success rate. These restorations are color stable and wear at a clinically acceptable rate. Wear of the luting composite on occlusal surfaces leads to the phenomenon of submargination. Ceramic fracture, wear at the interface and post-operative hypersensitivity remain a problem which require further investigation.

Ceramics↗
PubMed2006

Combined application of behavior genetics and microarray analysis to identify regional expression themes and gene-behavior associations.

In this report we link candidate genes to complex behavioral phenotypes by using a behavior genetics approach. Gene expression signatures were generated for the prefrontal cortex, ventral striatum, temporal lobe, periaqueductal gray, and cerebellum in eight inbred strains from priority group A of the Mouse Phenome Project. Bioinformatic analysis of regionally enriched genes that were conserved across all strains revealed both functional and structural specialization of particular brain regions. For example, genes encoding proteins with demonstrated anti-apoptotic function were over-represented in the cerebellum, whereas genes coding for proteins associated with learning and memory were enriched in the ventral striatum, as defined by the Expression Analysis Systematic Explorer (EASE) application. Association of regional gene expression with behavioral phenotypes was exploited to identify candidate behavioral genes. Phenotypes that were investigated included anxiety, drug-naive and ethanol-induced distance traveled across a grid floor, and seizure susceptibility. Several genes within the glutamatergic signaling pathway (i.e., NMDA/glutamate receptor subunit 2C, calmodulin, solute carrier family 1 member 2, and glutamine synthetase) were identified in a phenotype-dependent and region-specific manner. In addition to supporting evidence in the literature, many of the genes that were identified could be mapped in silico to surrogate behavior-related quantitative trait loci. The approaches and data set described herein serve as a valuable resource to investigate the genetic underpinning of complex behaviors.

Alcoholism↗
PubMed2002

Endoscopic inguinal hernia repair in comparison with Shouldice and Lichtenstein repair. A systematic review of randomized trials.

AIMS: This article provides an overview of randomized studies which compare endoscopic hernia repair techniques (TAPP/TEP) with the Shouldice and Lichtenstein repair. METHODS: Systematic analysis of 33 published studies which meet the criteria of a randomized controlled trial with a high evidence level. RESULTS: The majority of the studies document statistically significant advantages of the endoscopic repair techniques in relation to wound pain (15/22), need for analgesics (16/21), return-to-work time (16/22) and physical activity (18/25), although only one study showed significant advantages of the Lichtenstein method. Six of 28 studies showed a lower morbidity in comparison to open approaches, although 22 of 28 studies documented no significant difference. The first long-term studies with follow-up periods between 5 and 6 years also show advantages of the endoscopic techniques. CONCLUSION: Even with cautious interpretation of the data, it is clear that endoscopic techniques are more comfortable for patients and that morbidity is no higher than for open procedures. Due to the short follow-up periods final evaluation regarding long-term complications and recurrence is not yet possible.

Digestive System Surgical Procedures↗
PubMed2001

Compartmentation of intracellular water in multicellular tumor spheroids: diffusion and relaxation NMR.

Diffusion and relaxation of water in C6 glioma and MLS human ovarian carcinoma spheroids were measured from 1D projections acquired using a 2D diffusion-relaxation correlation pulse sequence and processed by non-negative least-square (NNLS) analysis. Systematic underestimation of I(s) and ADC(s) were observed for I(s)/(I(s) + I(f)) < 0.001. In the presence of spheroids, two apparent diffusion coefficient (ADC) compartments were observed, where ADC(f), ADC(s), and I(f), I(s) are the respective ADCs and signal intensities of the fast and slow compartments. These compartments differed also in their T(2) relaxation (ADC(s) = 0.5-0.74 x 10(-5) cm(2)/s, T(2) = 36-45 ms; and ADC(f) = 2.2-2.8 x 10(-5) cm(2)/s, T(2) = 280-316 ms). The two ADC compartments and the slow T(2) compartment were consistent with slow exchange. The fast T(2) compartment showed a drift with diffusion weighting, suggesting that it represents water exchanging between compartments that differ in their ADC and T(2). Both ADC(s) and I(s) were markedly attenuated with increasing diffusion time (Delta) for Delta < 100 ms, and increased at longer Delta. These results are consistent with restricted diffusion and fast relaxation of intracellular water for short diffusion time (T(1)' = 46.6 ms), and with predominant extracellular contribution to ADC(s) at longer diffusion times. Magn Reson Med 46:68-77, 2001.

Animals↗
PubMed2006

Gene expression changes in the retina following optic nerve transection.

PURPOSE: To obtain and analyze the gene expression profiles of the retina following optic nerve transection (ONT). METHODS: An axotomy animal model was generated by taking a cross section of the optic nerve with care not to damage the adjacent blood supply. The extent of cell loss was evaluated by counting cells in the ganglion cell layer (GCL) of flat-mounted retinas stained with cresyl violet. Gene expression profiles of control and ONT retinas were analyzed with Agilent's rat oligo microarray slides. Differentially expressed genes were identified from three independent experiments and clustered based on their functions with expression analysis systematic explorer software. Real-time quantitative and semiquantitative RT-PCR were used to validate changes in gene expression levels. RESULTS: Gene expression changes in axotomized retinas were analyzed with rat oligo microarray slides containing 22,575 oligonucleotide probes that represent over 20,000 genes and expressed sequence tags (ESTs). The expression of 493 genes was increased more than 1.5 fold, including 85 that were upregulated more than 2 fold, and the expression of 113 genes was decreased 1.5 fold or more, including 21 that were downregulated more than 2 fold. Differentially expressed genes were clustered based on their functions. Several novel genes expressed in the GCL have been identified and their expression patterns in different tissues were analyzed. Among the genes differentially regulated in retinas with induced retinal ganglion cell (RGC) death, we have identified 13 genes that are mapped to known glaucoma loci and can be considered for mutation screening in patients with inherited forms of glaucoma. CONCLUSIONS: The gene expression profiles of the ONT retinas can be used to identify RGC-expressed genes, which may be essential for the morphological and physiological characteristics of RGCs. The results of this study can also be used to evaluate the molecular changes taking place in the retina in response to RGC loss.

Animals↗
PubMed2006

Diagnostic and predictive value of anti-cyclic citrullinated protein antibodies in rheumatoid arthritis: a systematic literature review.

OBJECTIVE: To evaluate the two generations of anti-cyclic citrullinated protein (CCP) antibodies as a diagnostic marker of rheumatoid arthritis (RA) and as a predictor of future development of RA in healthy subjects and in patients with early undifferentiated arthritis. METHODS: A systematic analysis of the literature published between 1999 and February 2006 was conducted. Data were collected on the sensitivity and specificity of the two generations of anti-CCP antibodies for diagnosing RA and predicting future development of the disease. RESULTS: Among 107 studies initially identified, 68 had interpretable data and were analysed. Diagnostic properties were assessed in 58 studies: mean (SD) sensitivity was 53 (10)% (range 41-68) and 68 (15)% (range 39-94) for anti-CCP1 and anti-CCP2, respectively; mean (SD) specificity was 96 (3)% (range 90-99) and 95 (5)% (range 81-100) for anti-CCP1 and anti-CCP2, respectively. Predictive properties were assessed in 14 studies; odds ratio (95% confidence interval) of anti-CCP1 and anti-CCP2 for the future development of RA were 20 (14 to 31) and 25 (18 to 35), respectively, among patients with early undifferentiated arthritis and 64.5 (8.5 to 489) and 28 (8 to 95), respectively, among healthy subjects. CONCLUSION: Sensitivity of the second generation of anti-CCP is close to that of rheumatoid factor, with a higher specificity, for distinguishing RA from other rheumatic diseases. Moreover, anti-CCP antibodies appear to be highly predictive of the future development of RA in both healthy subjects and patients with undifferentiated arthritis.

Adolescent↗
PubMed2003

The medical management of ectopic pregnancy: a meta-analysis comparing "single dose" and "multidose" regimens.

OBJECTIVE: Medical management of an unruptured ectopic pregnancy with intramuscular methotrexate is common and cost-effective. Two treatment protocols, the "single dose" and the "multidose," have been advocated and independently reported in the medical literature. This analysis systematically compares the success and prevalence of side effects of these two regimens. DATA SOURCES: Published data on women with an ectopic pregnancy medically managed were identified using a MEDLINE search from 1966 to 2001 using key words and review of the references of each manuscript. METHODS OF STUDY SELECTION: Studies were selected based on dosing regimen, number of subjects, and study quality. Data regarding outcome, number of doses administered, side effects, and baseline characteristics were extracted. Data were summarized, and the associations of failed management and the presence of side effects with treatment protocol were calculated. Baseline serum chorionic gonadotropin values and the presence of embryonic fetal actively were controlled for with multivariable logistic regression. TABULATION, INTEGRATION, AND RESULTS: The overall success rate for women treated with methotrexate for an ectopic pregnancy was 89% (1181 of 1327). The single dose was much more commonly used. The use of single dose was associated with a significantly greater chance of failed medical management than the use of the multidose in both crude (odds ratio [OR] 1.71; 1.04, 2.82) and adjusted analyses (OR 4.74; 1.77, 12.62). The single-dose regimen was associated with fewer side effects (OR 0.44; 0.31, 0.63). Women who experienced side effects were more likely to have successful treatment regardless of regimen. CONCLUSION: The multidose regimen is more effective than the single-dose regimen.

Abortifacient Agents, Nonsteroidal↗
PubMed2004

Risk of melanoma arising in large congenital melanocytic nevi: a systematic review.

Large congenital melanocytic nevi are cutaneous lesions regarded by many as premalignant; estimates of malignancy incidence range from 0 to 42 percent. Given the often complex and extensive nature of large congenital melanocytic nevi resection and reconstruction, the risk of malignant transformation is a crucial factor that surgeons and families must weigh when deciding whether or not to excise the lesion. The authors conducted a systematic analysis of data from the existing literature to critically evaluate the published studies and to establish a crude incidence rate for the risk of malignant melanoma transformation in large congenital melanocytic nevi. After a comprehensive literature search, they analyzed data from eight studies (containing a total of 432 large congenital melanocytic nevi patients) of sufficient scientific quality. Twelve patients (2.8 percent) in this sample developed cutaneous malignant melanoma during the reported follow-up periods. Using a subset of this data and comparing the incidence rates to those of the Surveillance, Epidemiology, and End Results population-based database using a standardized morbidity ratio, the authors found that the large congenital melanocytic nevi patients had an increased risk of melanoma (standardized morbidity ratio, 2599; 95 percent confidence interval, 844 to 6064) compared with the general population. Regarding treatment before developing melanoma in the 12 patients, 50 percent were observed before diagnosis, 17 percent had partial excision, 8.3 percent had dermabrasion, 8.3 percent had a chemical peel, and 17 percent did not have any treatment information. These combined data are clinically useful when consulting with the parents of children with large congenital melanocytic nevi and in the management of older patients with existing lesions. This study shows that there is a significantly increased risk of melanoma in large congenital melanocytic nevi patients. The data also reveal the need for a standardized definition of large congenital melanocytic nevi and a long-term, prospective outcomes study to determine the true lifetime risk of melanoma in patients with and without surgical excision.

Humans↗
PubMed2001

[Psychological mechanisms in the transition from acute to chronic pain: over- or underrated?].

INTRODUCTION: During the last 20 years a great number of studies have emphasized the potential role of psychological factors as relevant predictors for the first onset of back pain as well as for the development of chronic pain. The formulation of a biopsychosocial perspective of the etiology and chronicity of back pain was a natural consequence. Actual questions concern the relative impact of psychological risk factors in the process of chronicity of back pain compared to biomedical, social and occupational factors. METHODS: Whereas several review articles regarding the role of psychological risk factors are available up to now, a recently published review conducted by Steven Linton was the first systematic analysis of well controlled prospective studies published since 1967. Using a grading system similar to that recommended for guidelines the author defined a level A evidence when at least two good-quality prospective studies supported the prospective power of a variable. Level B evidence had support from one prospective study. Level C represented inconclusive data and level D indicated that no studies met the criteria. Based on a literature search of more than 900 studies, 37 good-quality prospective studies were analysed in detail. RESULTS: The results indicated level A evidence for the following interrelations: (1) Psychosocial variables, especially chronic distress in daily life, depression and work dissatisfaction were clearly associated with the onset of back and neck pain (2). Psychological variables, especially chronic stress in daily life, work dissatisfaction, depression and pain-related cognitions and coping behaviour were clearly linked to the transition from acute to chronic pain and disability (3). Psychological variables generally had more prospective power than biomedical, social or objective occupational variables. Among the pain-related cognitions, catastrophizing and fear-avoidance-beliefs yielded the most empirical support. Among coping behaviour passive coping stretegies such as avoiding behaviour was most important. At least level B evidence has been shown for the counterpart of an extreme suppressive coping behaviour. Patients who tended to suppress or ignore pain in order to finish all activities they started, who were unable to integrate phases of passive relaxation into the daily routine displayed a high risk of chronicity of pain 6 months after an acute phase of pain. One international and two German good-quality prospective studies have shown the predictive power of a maladaptive suppressive behaviour pattern. Based on the avoidance-endurance-model of pain chronification, both extreme and one-sided passive pain coping as well as one-sided suppressive coping modes were conceptualized as maladaptive due to the process of chronicity. We assume that extreme passive behaviour will lead to immobility and muscular atrophy. Neurophysiological processes of sensitization will further lead to the development of chronic pain. On the other hand, extreme suppressive behaviour will lead to an overuse of muscles and joints with a repetitive combination of muscular hyperactivity and pain. These repetitive pain experiences will also elicit neurophysiological processes of sensitization. (4) Psychosocial variables displayed more predictive power than biomedical or biomechanical factors. (5) Psychosocial factors may be used as predictors of the risk for developing long-term pain and disability. Mixed empirical evidence has been shown for the role of personality factors (level C evidence) and no support has been found for the idea of a "pain prone" personality disorder or for the role of sexual and physical abuse. DISCUSSION: 20 years of research, several qualitative reviews and a recently published systematic review of 37 good-quality prospective studies regarding the role of psychological, biomedical, social and objective occupational factors in the process of chronicity of back pain revealed that psychological factors are significantly related to the onset of back pain as well as to the development of chronic pain. Furthermore, the psychological factors displayed more predictive power than biomedical or biomechanical variables. As a consequence for clinical practice, these psychological risk factors have to be considered as "yellow flags" if a back pain problem won't respond to medical treatment for more than four weeks. As a further consequence, special risk factor - based psychosocial interventions should be offered in addition to the medical treatment to patients with high psychological risk factors for the development of chronic pain. The efficacy of such an interdisciplinary care in the very early phases of back pain in order to prevent chronicity of pain and disability has been published recently by our group.

Acute Disease↗