Systematic review of rotator cuff tears in workers' compensation patients.

BACKGROUND: The burden imposed by workplace rotator cuff (RC) injuries has been reasonably defined. However, literature associated with the demographic characteristics and 'best practices' to manage such injuries among workers' compensation (WC) patients is scant. AIMS: To consolidate the existing literature on full-thickness RC tears among WC patients. Subject, shoulder and injury characteristics were examined to determine if and how WC recipients may differ from their non-compensable counterparts. METHODS: A systematic search (databases, clinical practice guideline web resources, conference proceedings and reference lists) revealed 450 abstracts. Two blinded reviewers independently assessed abstracts for inclusion. Sixty abstracts were subsequently included in a blinded full manuscript review. Seventeen of these manuscripts (3.8% of sample; 11 intervention and 6 determinant) were included in the present review. RESULTS: Previous studies demonstrate that operative interventions are appropriate for full-thickness RC tears as substantial gains in range of motion, strength and quality of life were witnessed within the first post-operative year. Non-operative interventions, including workplace-based work hardening, physical therapy and the use of an early referral system, were shown to improve outcomes. Conflicting results exist with respect to determinants such as age and sex. Importantly, WC patients had consistently poorer outcomes than non-WC patients. CONCLUSIONS: Our results show that although WC patients experience substantial benefits from various treatments for full-thickness RC tears, disparities exist between them and their non-WC counterparts. The lack of WC-specific literature limited our results. Larger studies, particularly ones comparing WC patients with their non-compensable counterparts, are crucial to allow for future evidence-based recommendations.

Cost effectiveness of prophylaxis in dental practice to prevent infective endocarditis.

BACKGROUND: Although antimicrobial prophylaxis for infective endocarditis (IE) is common practice for many dental procedures, there is little information on whether it represents value for money. A study was performed to evaluate the effectiveness of prophylaxis for all at risk patients in routine dental practice with published data from the United Kingdom. METHODS: The risk of contracting infective endocarditis was calculated from published data to find (for high risk patients) both the annual number of deaths attributable to infective endocarditis and the number of high risk dental procedures performed without prophylaxis. Costs are estimated by examining the notes of 63 patients with proved IE during the decade 1980-90. RESULTS: Such prophylaxis is highly cost effective before dental extractions, but its value for other invasive dental procedures is unproved. It was calculated that, for every 10,000 extractions in at risk patients, appropriate prophylaxis will prevent 5.7 deaths and a further 22.85 cases of non-fatal IE. This represents a saving in the costs of hospital care of 289,600 pounds for 10,000 extractions. CONCLUSION: Prophylaxis to prevent IE in at risk patients undergoing dental extraction is highly cost effective. Net savings each year throughout the United Kingdom, that might be achieved by improving the existing proportion of such patients given antibiotics from its present level of about 50% would amount to 2.5 million pounds and would prevent over 50 deaths.

Towards measurement of outcome for patients with varicose veins.

OBJECTIVE: To develop a valid and reliable outcome measure for patients with varicose veins. DESIGN: Postal questionnaire survey of patients with varicose veins. SETTING: Surgical outpatient departments and training general practices in Grampian region. SUBJECTS: 373 patients, 287 of whom had just been referred to hospital for their varicose veins and 86 who had just consulted a general practitioner for this condition and, for comparison, a random sample of 900 members of the general population. MAIN MEASURES: Content validity, internal consistency, and criterion validity. RESULTS: 281(76%) patients (mean age 45.8; 76% female) and 542(60%) of the general population (mean age 47.9; 54% female) responded. The questionnaire had good internal consistency as measured by item-total correlations. Factor analysis identified four important health factors: pain and dysfunction, cosmetic appearance, extent of varicosity and complications. The validity of the questionnaire was demonstrated by a high correlation with the SF-36 health profile, which is a general measure of patients' health. The perceived health of patients with varicose veins, as measured by the SF-36, was significantly lower than that of the sample of the general population adjusted for age and a lower proportion of women. CONCLUSION: A clinically derived questionnaire can provide a valid and reliable tool to assess the perceived health of patients with varicose veins. IMPLICATIONS: The questionnaire may be used to justify surgical treatment of varicose veins.

An assessment of Marr's theory of the hippocampus as a temporary memory store.

The recent reawakened interest in 'neural' networks begs the question of their relevance to the analysis of real nervous systems. Network models have been criticized for the lack of realism of their individual components, and because the architectures required by some neural-network algorithms do not seem to exist in real nervous systems. In three related papers published in the 1970s, David Marr proposed that the cerebellum, the neocortex and the hippocampus each acts as a memorizing device. These theories were intended to satisfy the biological constraints, but in computational terms they are undetermined. In this paper we reassess Marr's theory of the hippocampus as a temporary memory store. We give a complete computational account of the theory and we show that Marr's computational arguments do not sufficiently constrain his choice of model. We discuss Marr's specific model of temporary memory with reference to the neurophysiology and neuroanatomy of the mammalian hippocampus. Our analysis is supported by simulation studies done on various memory models built according to the principles advocated by Marr.

An assessment of cell-mediated immunity in acute allograft rejection in man. A prospective study.

A detailed multifactorial computer analysis of several in vitro tests of cell-mediated immunity has been carried out before and after surgery in 15 renal transplant recipients. Factors studied include lymphocyte blastogenesis, T- and B-cell levels, and lymphocyte protein synthesis. Large doses of immunosuppressive agents chnage lymphocyte subpopulations. This is seen especially in transplant patients who have rejection and who have decreased numbers of circulating lymphocytes. The T cells are selectively depressed more than the B cells. This is also reflected in the greater responsiveness of pokeweed mitogen-stimulated lymphocytes compared with lymphocyte responsiveness to phytohemagglutinin and concanavalin A. In this environment, rejection takes place. These observations suggest that rejection may be initiated by cortisone-resistant lymphocytes of the thymic medullary type. Measurements of changes in lymphocyte responsiveness to mitogens or changes in lymphocyte subpopulations do not reliably predict rejection. However, measurement of lymphocyte protein synthesis fills the criterion of providing a reliable test that can be carried out quickly, and in the future may be valuable in predicting rejection.