Risk factors for low back pain and sciatica in elderly men-the MrOS Sweden study.

Introduction: The aim of this study was to identify whether factors beyond anatomical abnormalities are associated with low back pain (LBP) and LBP with sciatica (SCI) in older men. Material and Methods: Mister Osteoporosis Sweden includes 3,014 men aged 69­81 years. They answered questionnaires on lifestyle and whether they had experienced LBP and SCI during the preceding 12 months. About 3,007 men answered the back pain (BP) questions, 258 reported BP without specified region. We identified 1,388 with no BP, 1,361 with any LBP (regardless of SCI), 1,074 of those with LBP also indicated if they had experienced LBP (n = 615), LBP+SCI (n = 459). Results: About 49% of those with LBP and 54% of those with LBP+SCI rated their health as poor/very poor (P < 0.001). Men with any LBP to a greater extent than those without BP had poor self-estimated health, depressive symptoms, dizziness, fall tendency, serious comorbidity (diabetes, stroke, coronary heart disease, pulmonary disease and/or cancer) (all P < 0.001), foreign background, were smokers (all P < 0.01), had low physical activity and used walking aids (all P < 0.05). Men with LBP+SCI to a greater extent than those with LBP had lower education, lower self-estimated health, comorbidity, dizziness and used walking aids (all P < 0.001). Conclusions: In older men with LBP and SCI, anatomical abnormalities such as vertebral fractures, metastases, central or lateral spinal stenosis or degenerative conditions may only in part explain prevalent symptoms and disability. Social and lifestyle factors must also be evaluated since they are associated not only with unspecific LBP but also with LBP with SCI.

Optimization of radiation exposure and image quality of the cone-beam O-arm intraoperative imaging system in spinal surgery.

STUDY DESIGN: Retrospective study. OBJECTIVES: To optimize the radiation doses and image quality for the cone-beam O-arm surgical imaging system in spinal surgery. SUMMARY OF BACKGROUND: Neurovascular compromise has been reported after screw misplacement during thoracic pedicle screw insertion. The use of O-arm with or without navigation system during spinal surgery has been shown to lower the rate of screw misplacement. The main drawback of such imaging surgical systems is the high radiation exposure. METHODS: Chest phantom and cadaveric pig spine were examined on the O-arm with different scan settings: 2 were recommended by the O-arm manufacturer (120 kV/320 mAs, and 120 kV/128 mAs), and 3 low-dose settings (80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs). The radiation doses were estimated by Monte Carlo calculations. Objective evaluation of image quality included interobserver agreement in the measurement of pedicular width in chest phantom and assessment of screw placement in cadaveric pig spine. RESULTS: The effective dose/cm for 120 kV/320 mAs scan was 13, 26, and 69 times higher than those delivered with 80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs scans, respectively. Images with 60 kV/40 mAs were unreliable. Images with 80 kV/80 mAs were considered reliable with good interobserver agreement when measuring the pedicular width (random error 0.38 mm and intraclass correlation coefficient 0.979) and almost perfect agreement when evaluating the screw placement (κ value 0.86). CONCLUSIONS: The radiation doses of the O-arm system can be reduced 5 to 13 times without negative impact on image quality with regard to information required for spinal surgery.

Characteristics of Prevalent Vertebral Fractures Predict New Fractures in Elderly Men.

BACKGROUND: Studies have shown that specific characteristics of prevalent vertebral fractures are associated with a markedly low bone mineral density. This study evaluates if these characteristics also predict subsequent fractures. METHODS: MrOS (Mister Osteoporosis) Sweden is a population-based, prospective observational study that includes 3014 community-living men who are sixty-nine to eighty-one years of age. At baseline, 1453 men underwent lateral thoracic and lumbar spine radiography; radiographs of 1427 men were readable. A radiologist identified and characterized prevalent vertebral fractures. Incident fractures during the next five and ten years were objectively registered with use of radiographs. The annual fracture incidence and relative risk of sustaining new fractures were assessed for men with and without baseline prevalent vertebral fracture. Data are presented as the mean and the 95% confidence interval. RESULTS: There were 215 men (15.1%) with at least one prevalent vertebral fracture. During the five-year follow-up, these men had a relative risk of 3.3 (95% confidence interval, 2.6 to 4.3) of sustaining new fractures. The relative risk of sustaining any fracture was especially high in men with two or more prevalent vertebral fractures at 5.5 (95% confidence interval, 3.7 to 7.8), in men with different types of prevalent vertebral fractures at 5.7 (95% confidence interval, 3.6 to 8.5), in men with prevalent fractures in both the thoracic and lumbar regions at 6.4 (95% confidence interval, 4.5 to 8.8), and in men with prevalent fractures with a degree of vertebral body compression in the three worst quartiles, with the relative risk for the worst quartile at 4.0 (95% confidence interval, 2.6 to 5.9). CONCLUSIONS: Older men with a prevalent vertebral fracture have three times increased risk of sustaining new fractures compared with men without a vertebral fracture. Older men with two or more prevalent vertebral fractures, different types of fractures (wedge, biconcave, and/or crush), fractures in both the thoracic and lumbar regions, and a degree of vertebral body compression in the three worst quartiles are at an especially high risk of sustaining new fractures. Older men with prevalent vertebral fractures should be considered for fracture-prevention efforts.

Low clinical relevance of a prevalent vertebral fracture in elderly men--the MrOs Sweden study.

BACKGROUND CONTEXT: The epidemiology, the fracture pattern, and the clinical relevance of prevalent vertebral fractures in old men are debated wherefore we set out to clarify these issues. METHODS: Mister Osteoporosis (MrOs) Sweden is a population-based cohort of community-living men aged 69-81 years that includes 3,014 men. Out of these, 1,453 men underwent a lateral radiograph of the thoracic and lumbar spine of which 1,427 were readable and classified by a radiologist, that is the sample size in this study. The men also answered a questionnaire evaluating back pain and limitation in activities of daily living (ADLs) because of back pain during the preceding 12 months in addition with fracture history and life style. RESULTS: Fifteen percentage of the men had at least one prevalent vertebral fracture, but only 1/10th of these were aware of their fracture. Among the men with a fracture, 58% had one, 21% two, 9% three, and 11% four or more fractures. In men with only one fracture, 70% of the fractures were located in the thoracic and 30% in the lumbar spine, 85% had a wedge, 13% a biconcave, and 2% a crush-type configuration; one-quarter had a maximum vertebral body compression degree of less than 24% and one-quarter of more than 38%. Among the men with one or several vertebral fracture, 57% reported back pain compared with 55% in those without a fracture (p=.53). Most ADL functions were similar in the men with or without a prevalent vertebral fracture. In the men with one fracture, there was no difference in the occurrence of back pain depending on the fractured region (p=.49), type of the fracture (p=.77), or degree of compression (p=.85). In men with one or several fractures, there were no significant differences in the presence of back pain in any ages (p=.08), nor there were differences in presence of back pain regarding type (p=.08) or number of fractures (p=.21). CONCLUSIONS: A prevalent vertebral fracture is common in old men but has low clinical relevance. There does not seem to be a specific fracture pattern that predisposes for back pain.