Motor vehicle rollover and static stability: an exposure study.

OBJECTIVES: This study examined vehicle rollovers in terms of site-specific exposure and speeds of vehicles of varying stability. METHODS: Fifty-one rollover sites in two states were visited at the same time of day and day of week as the rollover. A sample of vehicles moving in the same direction as the rollover were observed, and vehicle-specific data were obtained from identification numbers. RESULTS: Low stability, exacerbated by the addition of passengers, increased the risk of rollover. Speed was not correlated with stability and is not a confounder. CONCLUSIONS: Rollovers could be substantially reduced if motor vehicles were manufactured with a static stability of 1.2 or greater.     

Effects of 1-week head-down tilt bed rest on bone formation and the calcium endocrine system.

To understand the potential early responses of human bone and the calcium endocrine system to spaceflight, we studied 8 healthy men, aged 35-44 years before, during, and after bed rest in a -6 degrees head-down tilt model for microgravity. Based on a novel single-dose labeling schedule, average rates of bone formation in the iliac crest were reduced in 6, unchanged in 1, and increased in 1 following the bed rest period. The decrease was greatest for subjects whose daily walking miles were highest (r = -0.762, p less than 0.05, n = 7). Before a measurable increase in ionized serum calcium the sixth bed rest day, there was increased excretion of urinary calcium and sodium, evident the first 2 bed-rest days and parallel for the entire week (r = 0.92, p less than 0.001). Reduced excretion of phosphorus and 3', 5' cyclic adenosine monophosphate on the first and second bed rest days was followed by an increase in serum phosphorus by the sixth bed rest day. Depressed serum concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D were manifest by the sixth and seventh bed rest days. The similarity of the response of bone and the calcium endocrine system of healthy men after only 7 days to results of longer term bed rest studies emphasizes the responsiveness of the adult human skeleton to biomechanical stimuli induced by changes in activity and/or position.     

The efficacy of nasal septal surgery.

Nasal septal deformity is a frequent clinical entity, and septoplasty comprises one of the most common procedures performed by otolaryngologists today. Its efficacy seems intuitive, however the literature reveals relatively few papers confirming its utility. In this study, all patients undergoing septal reconstruction (excluding septorhinoplasty) at three major teaching hospitals in Vancouver during the years 1988 to 1990 were reviewed retrospectively in a two-pronged study. Information was collected concerning symptoms, physical findings and surgical technique. In the second phase, patients were contacted by telephone in a blinded fashion. Data was collected concerning patient satisfaction regarding various parameters including initial and ultimate symptom resolution, acceptance of nasal packing and postoperative complications. The following conclusions may be drawn: 1) Septoplasty was successful in relieving nasal obstruction in 70.5% of patients. 2) Turbinate surgery including outfracturing appears to significantly improve the outcome of surgery. 3) Rhinitis, including allergy, congestion, postnasal drip and rhinorrhea did not significantly affect success in relieving nasal obstruction. 4) Nasal packing did not significantly affect the outcome, but was the most frequently complained of aspect of the surgery. Therefore, we do not feel nasal packing is necessary.     

The influence of continuous passive motion on outcome in total knee arthroplasty

All primary condylar total knee replacement arthroplasties (TKAs) performed from 1977 to 1984 at the authors' institution were divided into two groups based on the use of continuous passive motion (CPM) in the immediate postoperative period. The control group consisted of 73 patients who were treated with 95 TKAs without postoperative CPM. The average age was 65.4 years. The study group consisted of 38 patients who had 51 TKAs in which CPM was used postoperatively. The mean patient age was 62.8 years. The most common diagnoses in both groups were osteoarthritis and rheumatoid arthritis. Range of motion (ROM) was recorded preoperatively, at discharge, at three months, one year, two years, and at the last follow-up visit. There were no statistically significant differences in the ROM between the two groups at any of these time periods. At two years, the mean flexion and extension in the study group were 99 degrees and -4 degrees, respectively, compared to 103 degrees and -5 degrees in the control group. The average hospital stay was 11.2 days in the study group, whereas it was 15.1 days in control group. In the control group, there was one superficial infection, no deep infections, and four pulmonary emboli compared with three superficial infections, two deep infections, and no pulmonary emboli in the study group. There was no difference in the transfusion requirements between the two groups. CPM is advocated by the authors to help achieve discharge ROM earlier, but the protocol has been changed to begin CPM on the second postoperative day to allow the wound to stabilize.     

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.