RESUMO
BACKGROUND: Burst fractures involving the L5 vertebra are quite rare . They can be managed with anterior, posterior, or combined 360 approaches. Here, we report a 25-year-old female who presented with a traumatic cauda equina syndrome attributed to an L5 burst fracture following a motor vehicle accident, and who did well after a posterior-only decompression/fusion. CASE DESCRIPTION: A 25-year-old female presented with a traumatic cauda equina syndrome attributed to an L5 burst fracture following a motor vehicle accident. She was treated with a posterior-only vertebrectomy and followed for 5 postoperative months. During this time, she experienced complete resolution of her preoperative neurological deficit and demonstrated radiographically confirmed spinal stability. CONCLUSION: One of the major pros for the all-posterior L5 corpectomy as in this case, was that the patient underwent a successful single-stage, single-position operation. However, the posterior-only L5 corpectomy approach is technically demanding, and only allows for the placement of a lower profile interbody cage.
RESUMO
Medical students have difficulty understanding the mechanisms underlying hyperkalemia-mediated local control of blood flow. Such control mechanisms are crucial in the brain, kidney, and skeletal muscle vasculature. We aimed to identify medical students' misconceptions via assessment of students' in-class knowledge and, subsequently, improve future teaching of this concept. In-class polling was performed with the TurningPoint clicker response system (n = 860) to gauge students' understanding of three physiological concepts related to hyperkalemia: membrane potential (Vm), conductance, and smooth muscle response. Vm includes the concepts of equilibrium potential (Veq) for specific ions, as well as driving force (DF = Vm - Veq). Students understood the concept of DF (~70% answered correctly), suggesting their understanding of Vm. However, students misunderstood that hyperkalemia results in depolarization (~52% answered correctly) and leads to an increase in potassium conductance (~31% answered correctly). Clarification of the type of smooth muscle as vascular increased the percentage of correct responses (~51 to 73%). The data indicate that students lacked knowledge of specific potassium conductance in various muscle types, resulting in divergent responses, such as the canonical depolarization in skeletal muscle versus hyperpolarization in smooth muscle cells during hyperkalemia. Misunderstanding of this crucial concept of conductance is directly related to the students' performance. Furthermore, we connected the paradoxical effect of hyperkalemia to pathological acute and chronic hyperkalemia clinical scenarios.