Journal of spinal disorders
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Comparative Study
Effect of spinal cord ischemia on compound muscle action potentials and spinal evoked potentials following spinal cord stimulation in the dog.
We recorded the compound muscle action potentials (CMAP) from the soleus muscle and spinal evoked potentials (SpEP) from the caudal spinal cord after stimulation of the rostral spinal cord via epidural electrodes in 18 dogs. We examined the changes of CMAP and SpEP after the cord was made ischemic by clamping the aorta at different levels. Clamping the abdominal aorta below the artery of Adamkiewicz (five dogs) did not change either CMAP or SpEP significantly. ⋯ Then CMAP disappeared, but SpEP remained unchanged. These findings suggest that CMAP and SpEP are mediated through different pathways and that CMAP reflect anterior cord function. The described electrophysiologic technique would be useful to monitor spinal cord motor function during surgery of the spine, spinal cord, or thoracoabdominal aorta.
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We present two cases of fatal venous air embolism that occurred in previously healthy adolescents during posterior spine fusion and instrumentation for scoliosis. Previously recorded cases in the literature have been rare and only briefly discussed. Air embolism has been a complication noted in the anesthesia and neurosurgical literature, occurring primarily in total hip patients and those patients undergoing neurosurgical procedures in a sitting position. An examination of the pathophysiology of air embolism in posterior spinal procedures would indicate the use of properly placed central lines and end-expiratory CO2 monitoring as the primary modes of detection and treatment considering the potentially fatal risk factors for spinal patients.
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We are reporting our experience in 23 patients with tumors of the thoracic or lumbar vertebrae treated via surgical anterior decompression and stabilization. Seventeen patients had metastatic disease and were treated with vertebral body resection followed by stabilization with anterior polymethylmethacrylate and threaded Harrington rods with sacral distraction hooks. Six patients had primary tumors and, following tumor resection and partial vertebral body resection, had autogenous bone graft struts placed anteriorly as well as posterior instrumentation. ⋯ Tumor recurrence with neurologic deterioration occurred in two patients. We are very encouraged by these results, and we recommend that patients with tumors of the vertebral body with neurologic deficit or severe unremitting pain be studied with MRI and/or myelography and CT. The patients with gross vertebral destruction and greater than 50% collapse of the vertebral body, those in need of a tissue diagnosis, or those with major neurologic deficit can be effectively treated by anterior decompression and stabilization.