Judith I. Kuiper

Epidemiologic evidence on manual materials handling as a risk factor for back disorders:a systematic review

Abstract In this review, epidemiologic evidence on the role of manual materials handling in the occurrence of back disorders was systematically evaluated. Twenty-five publications that provided quantitative data on associations between manual materials handling and back disorders were selected. Study findings were evaluated on the basis of strength of association, consistency in findings and dose–response relations. The methodological quality of each study was assessed to consider the relative value of the findings. Although a considerable number of epidemiologic studies investigated the risk of lifting, only a moderate insight in the dose–response relation between exposure to lifting and occurrence of back disorders was found. Evidence on carrying and on pushing/pulling as risk factor for back disorders was very limited. Only very few quantitative studies were performed and the results of these studies were inconsistent. The amount of evidence on the risk of exposure to combined manual materials handling was only moderate. It was concluded that, based on the criteria applied in this study, epidemiologic evidence for manual materials handling as risk factor of back disorders is present, but largely based on cross-sectional studies with inherent methodological weaknesses. More longitudinal studies need to be performed in which special attention is given to accurate exposure measurements, valid assessment of back disorders, and dose–response relations. Relevance to industry Manual materials handling is considered a major cause of back disorders in industry. Epidemiologic evidence for the risk of manual materials handling is evaluated, and points of special interest for future epidemiologic studies, which are needed to provide a scientific basis for quantitative guidelines, are discussed.

Treatment of Impingement Syndrome: A Systematic Review of the Effects on Functional Limitations and Return to Work

The goal of this systematic review is to evaluate the effectiveness of different treatments for impingement syndrome and rotator cuff tear on the improvement in functional limitations and concomitant duration of sick leave. A systematic search for clinical trials or controlled studies was conducted with the following text words: should*, rotator cuff, impingement, work, sick leave, disabilit*, function*. Nineteen articles were included in this review. For functional limitations, there is strong evidence that extracorporeal shock-wave therapy is not effective, moderate evidence that exercise combined with manual therapy is more effective than exercise alone, that ultrasound is not effective, and that open and arthroscopic acromioplasty are equally effective on the long term. For all other interventions there is only limited evidence. We found many studies using range of motion and pain as outcome measures but functional limitations were less often used as an outcome measure in this type of research. Duration of sick leave was seldom included as an outcome measure.

Psychosomatic complaints and unwinding of sympathoadrenal activation after work.

It is well known that chronically elevated catecholamine excretion rates are associated with health problems, indicating the importance of recovery after work. In 28 male truck drivers, unwinding after work was found to be insufficient. The resulting spillover of sympathoadrenal activation, as assessed by urinary excretion rate of adrenaline and noradrenaline, was significantly related to self-reported psychosomatic health complaints. Age had a significant effect on spillover of noradrenaline, whereas this personal factor was only marginally significant for adrenaline. This study shows that elevated sympathoadrenal activation after work, and not only increased reactivity during work, causes health problems, although it is also plausible that young and healthy drivers are able to unwind more quickly than older drivers with psychosomatic complaints

Interventions for treating the posterior interosseus nerve syndrome: a systematic review of observational studies

Abstract  For the posterior interosseus nerve syndrome (PINS), no randomised controlled trials or controlled clinical trials about the effectiveness of interventions are available; only case series can be found. Although the validity of case series is inferior to controlled trials, they may provide valuable data about the efficacy of treatment options. Therefore, we systematically reviewed all available observational studies on treatment of PINS. A literature search and additional reference checking was done. On the basis of previous checklists, we constructed a quality assessment and rating system to analyse the included case series. Studies with less than 50% of the maximum points on the methodological quality assessment were excluded from the analysis. The results are summarised according to a rating system for the strength of the scientific evidence. Six eligible case series for this review were found. After the data extraction and methodological quality assessment, two higher quality studies that evaluated the effectiveness of surgical decompression of the PIN were included in the final analysis. There is a tendency for the effectiveness of surgical decompression of the PIN in patients with PINS. The effectiveness of a conservative treatment for PINS is unknown because no higher quality studies are available. Additional high‐quality controlled studies are needed to assess the level of ‘conclusive evidence’ for surgical treatment. There is also a need for high‐quality controlled trials into the effectiveness of conservative treatments for PINS.

Keratan Sulfate as a Potential Biomarker of Loading of the Intervertebral Disc

Study Design. A review of the literature. Objective. To investigate the potential of serum levels of keratan sulfate as a biomarker of the effects of loading of the spine. Summary of Background Data. Exposure to mechanical loading of the spine causes changes in metabolism of intervertebral discs, eventually leading to accelerated disc degeneration. This process is characterized by the degradation of proteoglycans, which is reflected by an increase in the blood level of proteoglycan components. The serum level of keratan sulfate, an epitope present on these proteoglycan components, has been suggested as a marker of changes in metabolism of cartilaginous tissues. Methods. A review of the literature on serum keratan sulfate levels in relation to degenerative changes in cartilaginous tissue. Results. In a number of studies keratan sulfate in serum was reported to be related to degeneration of articular cartilage in patients with osteoarthritis. In addition, massive and rapid degradation of intervertebral discs was determined to result in a large rise in serum keratan sulfate levels. Whether degenerative changes of intervertebral discs induced by mechanical stress also cause a detectable increase in serum keratan sulfate should be subjected to further investigation. Conclusion. Quantification of keratan sulfate in serum offers a promising measure for the early effects of mechanical loading of the spine, but research is needed for validation.

Serum markers of collagen metabolism: construction workers compared to sedentary workers

Background: Evaluation of causal relations between physical load and musculoskeletal disorders is hampered by the lack of knowledge as to the biological relevance of different loading parameters and the large variability between individuals. As indicators of molecular changes in the extracellular matrices of structures of the musculoskeletal system, biomarkers of collagen metabolism may provide important information on biological effects of physical load. The carboxyterminal propeptide of type I collagen (PICP) is a serum marker of synthesis and the carboxyterminal telopeptide region of type I collagen (CTx) reflects degradation of type I collagen. Aims: To explore the feasibility of biomarkers of type I collagen metabolism as measures of the effects of physical load at tissue level. Methods: Serum concentrations of PICP and CTx were assessed in a group of male construction workers involved in heavy manual materials handling (n = 47) and in a group of male sedentary workers (n = 49). Results: Serum concentrations of both PICP and CTx seemed to be related to heavy physical work. The ratio PICP/CTx, illustrative of the effective metabolic changes, did not differ between the two groups. Conclusions: The higher turnover rate but similar effective synthesis may be indicative of an increased type I collagen content in the connective tissues as a result of adaptive remodelling in response to years of exposure to physical load. Further validation of these biomarkers is required with respect to dose-response relations and temporal associations between exposure to back load and biomarker concentrations.

The Use of Biomarkers in Epidemiologic Research on the Association between Exposure to Mechanical Load and Back Disorders

Biomarkers can supplement traditional epidemiologic research on the causes of musculoskeletal disorders. As indicators of changes at tissue or molecular level in the structures in the back, biomarkers can improve the understanding of the intermediate steps between exposure to risk factors and the occurrence of back disorders. By providing exposure information that is specific to the individual, and to target tissues, biomarkers can help to reduce misclassification in exposure measures, and thus enhance our ability to detect dose-response relations. Because of the complex anatomy of the back and the multifactorial etiology of back disorders it is complicated to identify useful biomarkers. Degenerative changes in intervertebral discs are believed to play a crucial role in the relation between exposure to mechanical load and back disorders. Based on the literature various potential biomarkers of degenerative changes in intervertebral discs are selected and four different studies are performed to investigate their feasibility as tools in epidemiologic research.