European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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Low back pain (LBP) in children was considered for many years to be a rare condition revealing a serious disease, but in the last two decades, epidemiological studies have shown that the prevalence of nonspecific LBP in children is high. This study was aimed at analyzing the prevalence, severity, consequences and associated factors of LBP in children. A cross-sectional study was undertaken in two preparatory schools in the city of Monastir, Tunisia, in April 2002. ⋯ Two factors were associated with chronic LBP: dissatisfaction with school chair, OR=1.62 (95% CI, 1.46-3.32) and football playing, OR=3.07 (95% CI, 2.15-5.10). The prevalence of LBP among Tunisian schoolchildren and adolescents is high. This requires preventive measures and longitudinal studies, which are very important from the standpoint of public health.
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This work aimed to evaluate trunk muscle forces, internal loads and stability margin under some simulated standing postures, with and without external loads, using a nonlinear finite element model of the T1-S1 spine with realistic nonlinear load-displacement properties. A novel kinematics-based algorithm was applied that exploited a set of spinal sagittal rotations, initially calculated to minimize balancing moments, to solve the redundant active-passive system. The loads consisted of upper body gravity distributed along the spine with or without 200 N held in the hands, either in the front of the body or on the sides. ⋯ Co-activation in abdominal muscles (up to 3% maximum force) substantially increased extensor muscle forces, internal loads and stability margin, allowing a smaller critical muscle coefficient. A tradeoff existed between lower internal loads in passive tissues and higher stability margins, as both increased with greater muscle activation. The strength of the proposed model is in accounting for the synergy by simultaneous consideration of passive structure and muscle forces under applied postures and loads.
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Cervical spine fractures in patients with ankylosing spondylitis are serious and potentially lethal injuries with high complication rates. Treatment obstacles include long lever arms that generate large forces on any fixation device, osteoporosis, and, usually, kyphotic deformity. The Olerud Cervical Fixation System (OC), with cervical pedicle screws and rods, offers an opportunity to create a biomechanically stable posterior fixation in these complicated cases. ⋯ Extensive peroperative bleeding was encountered in two patients. One deep-wound infection was noted, postoperatively, and required surgical drainage, but no patients have been re-operated due to loosening of the instrument or to healing problems. In conclusion, the results of the present study indicate that the OC--and possibly other similar long-fixation systems that allow using both pedicle screws and lateral mass screws rigidly connected to a rod--is suited for treating subaxial cervical spine fractures in patients with ankylosing spondylitis, allowing high healing rates.
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Cervical disc injury due to frontal impact has been observed in both clinical and biomechanical investigations; however, there is a lack of data that elucidate the mechanisms of disc injury during these collisions. The goals of the current study were to determine the peak dynamic disc annular tissue strain and disc shear strain during simulated frontal impact of the whole human cervical spine model with muscle force replication at 4 g, 6 g, 8 g and 10 g horizontal accelerations of the T1 vertebra. These data were compared with those obtained during physiological loading, and with previously reported rear impact data. ⋯ The C5-C6 intervertebral level was at high risk for injury during both frontal and rear impacts, while during frontal impact, in addition to C5-C6, subfailure injuries were likely at superior intervertebral levels, including C2-C3. The disc injuries occurred at lower impact accelerations during rear impact as compared with frontal impact. The subfailure injuries of the cervical intervertebral disc that occur during frontal impact may lead to the chronic symptoms reported by patients, such as head and neck pain.
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The total costs for patients who are sick-listed due to back and neck problems have not previously been determined prospectively on an individual basis. This study aimed to determine the total cost to a society, based on individually assessed costs of health services and loss of production in people who are sick-listed 28 days or more for back or neck problems. Detailed data on individuals' health-care consumption due to back or neck problems was collected through prospectively entered diaries and questionnaires, after 4 weeks, 3 months, 1 and 2 years, in a consecutively selected cohort of 1,822 employed persons aged between 18 and 59 years. ⋯ The single most expensive medical service was surgery. Transferred to a national level, annual total costs for back and neck problems corresponded to 1% of GNP. In conclusion, direct health-service costs were a small fraction of the total costs, consequently indirect costs offer the greatest potential for savings.