Magnet Fracture within a Magnetically Controlled Growing Rod: A Case Report of a New Mechanism of Failure

Introduction: Magnetically controlled growing rods (MCGRs) have been widely adopted in the management of early-onset scoliosis since they were first described in 2012. Recent reports have highlighted concerns around their safety. To date, little is understood about the risk factors and modes of failure in these devices. Case Report: We report a novel mechanism of device failure in a 14-year-old patient following multiple revisions of MCGRs. Clinically, there was no evidence of device failure and the MCGRs appeared radiologically intact. Explantation analysis revealed multiple compromised/non-functional components. A previously undocumented phenomenon of complete magnet fracture was also seen. Conclusion: The absence of clinical or radiological features of device failure in this case makes the findings of great concern. Given the relative paucity of high-quality evidence surrounding the use of MCGRs, we support calls for urgent comparative studies and further investigation of risk factors for device failure. Keywords: Spinal surgery, Scoliosis, Magnetically controlled growing rods, Implant.

Intraoperative Hardware Failure of the Fassier–Duval Rescue System in a Pediatric Patient with Osteogenesis Imperfecta

The use of telescopic intramedullary rods for the treatment of lower extremity deformity in children with osteogenesis imperfecta has been well described. The reinforcement of these weakened weightbearing bones with intramedullary devices leads to improvements in mobility that progress into adulthood. Although the current telescopic intramedullary rod systems are an upgrade from earlier systems, they are still associated with high rates of reoperation and complication. We describe a unique complication encountered during a revision which involved the male retriever system for the Fassier–Duval rod (FDR) (Pega Medical, Quebec, CA) experienced intraoperatively. To our knowledge, this mechanism of failure has not been previously described in the literature.

Analysis of Slope Stability

In the paper the numerical modelling of ensuring slope stability and their analysing with using of different numerical methods are presented. We have designed the cutting walls with earth nails and anchors securing for modelling of slope stability ensuring. The calculate and the mechanism of failure process of the reinforced slopes were studied using the different methods for slope stability. The nailing significantly increased the stability level for using Spencer method. The anchors increased the stability level for using Spencer method. Increasing the nail or anchors length improved the stability of the reinforced slopes. The reinforced slope exhibited a significant the stability level.

Assessment of stratification of the breeds of the underground cavity roof

Authors of the research consider the approach to the assessment of possibility of formation of stratification and shift cracks in the roof of extended horizontal cavity, based on the method of boundary elements. The algorithm implements the iterative procedure of variation of the formed crack length with control of tension in its tip. At the same time, the angle of the crack coasts closing is defined by the tensile strength of the layer material. The crack with smooth closing of coasts is formed in case of equality to zero this durability. The mechanism of failure forming over the developed space with vertical pipe type walls is considered. The results received by the authors, can be useful as the offered approach allows to model the destructions localization in the massif of rocks, location and sizes of the arising cracks of stretching and shift if there are strength defects in the massif