None of the authors received financial support for this study BI reports to be a consultant for Implanet, ZimmerBiomet and Medtronic KM reports to be consultant for Implanet Retrospective study approved by the Local Ethic Committee
Daily living activities are dynamic, requiring spinal motion through space. Current assessment of spinal deformities is based on static measurements from full-spine standing radiographs. Tools to assess dynamic stability during gait might be useful to enhance the standard evaluation. The aim of this study was to evaluate gait dynamic imbalance in patients with spinal deformity using the dynamic stability margin (DSM). Twelve normal subjects and 17 patients with spinal deformity were prospectively recruited. A kinematic 3D gait analysis was performed for the control group (CG) and the spinal deformity group (SDG). The DSM (distance between the extrapolated center of mass and the base of support) and time-distance parameters were calculated for the right and left side during gait. The relationship between DSM and step length was assessed using three variables: gait stability, symmetry, and consistency. Variables' accuracy was validated by a discriminant analysis. Patients with spinal deformity exhibited gait instability according to the DSM (0.25m versus 0.31m) with decreased velocity (1.1ms versus 1.3ms) and decreased step length (0.32m versus 0.38m). According to the discriminant analysis, gait stability was the more accurate variable (area under the curve AUC=0.98) followed by gait symmetry and consistency. However, gait consistency showed 100% of specificity, sensitivity, and accuracy of precision. The DSM showed that patients with spinal malalignment exhibit decreased gait stability, symmetry, and consistency besides gait time-distance parameter changes. Additional work is required to determine how to apply the DSM for preoperative and postoperative spinal deformity management.
Abstract-The goal of this study was to propose a general numerical analysis methodology to evaluate the magnetic resonance imaging (MRI)-safety of active implants. Numerical models based on the finite element (FE) technique were used to estimate if the normal operation of an active device was altered during MRI imaging. An active implanted pump was chosen to illustrate the method. A set of controlled experiments were proposed and performed to validate the numerical model. The calculated induced voltages in the important electronic components of the device showed dependence with the MRI field strength. For the MRI radiofrequency fields, significant induced voltages of up to 20 V were calculated for a 0.3T field-strength MRI. For the 1.5 and 3.0T MRIs, the calculated voltages were insignificant. On the other hand, induced voltages up to 11 V were calculated in the critical electronic components for the 3.0T MRI due to the gradient fields. Values obtained in this work reflect to the worst case situation which is virtually impossible to achieve in normal scanning situations. Since the calculated voltages may be removed by appropriate protection circuits, no critical problems affecting the normal operation of the pump were identified. This study showed that the proposed methodology helps the identification of the possible incompatibilities between active implants and MR imaging, and can be used to aid the design of critical electronic systems to ensure MRI-safety.Index Terms-Biomedical equipment safety, finite element methods, magnetic resonance imaging.
Purpose Extravasation of cytotoxic vesicant drugs is a surgical emergency (within six hours) since this incident can lead to severe skin and soft-tissue damage. Outcomes after the saline washout procedure have been extensively described in adults, but rarely in children. The aim of this study was to evaluate the outcome of early saline washout procedure for upper limb cytotoxic drug extravasation in children. Methods All consecutive children with vesicant drug extravasation were retrospectively reviewed. The saline washout procedure was performed. Cosmetic aspect, residual pain and range of movement were analyzed as well as time to surgery and chemotherapy resumption at last follow-up. Results Between 2014 and 2018, 13 cytotoxic vesicant drug extravasations occurred (mean age 8 years (sem 5)), including 11 treated by the saline washout procedure. At mean follow-up of 11 months (sem 7), the patients had no or low pain and ranges of movement were fully conserved. Two patients (one within the six hours’ delay) had soft-tissue necrosis leading to extensive reconstructive surgery. Conclusion The saline washout procedure is safe and easy and significantly reduces the incidence of extensive skin damage. Early referral to a specialized department is essential. However, the key parameter remains prevention by educating medical staff and nurses about these injuries and by training them for early and urgent management. Level of Evidence IV
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