Journal of neurosurgery
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Journal of neurosurgery · Sep 1980
Case ReportsElectrophysiological evaluation of phrenic nerve function in candidates for diaphragm pacing.
The electrophyisological status of phrenic nerve function has been determined by an assessment of the conduction time and diaphragm muscle action potential in patients who were being evaluated as candidates for diaphragm pacing, or who were being studied for suspected phrenic nerve injury or disease. The conduction time and muscle action potential were evoked by transcutaneous phrenic nerve stimulation or by stimulation with a permanently implanted diaphragm pacemaker. In normal volunteers the conduction time was found to be 8.40 msec +/- 0.78 msec (SD). ⋯ In patients who were selected for implantation of a diaphragm pacemaker, a conduction time that was prolonged (10 to 14 msec) preoperatively did not preclude successful diaphragm pacing. Postoperatively, a prolonged (> 10 msec) conduction time was associated with severe systemic disease or local nerve injury caused by trauma or infection. The elucidation of phrenic nerve function by such electrophysiological studies serves as a valuable adjunct to the selection and management of patients undergoing diaphragm pacing.
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Journal of neurosurgery · Sep 1980
Spinal cord energy metabolism following compression trauma to the feline spinal cord.
The purpose of this study was to determine the spinal cord metabolic state for 24 hours after compression trauma to the feline spinal cord. Cats were anesthetized with pentobarbital and injured by placing a 190-gm weight on the spinal cord for 5 minutes. Biochemical analysis of the injured segment revealed a significant depletion in the levels of adenosine triphosphate (ATP), phosphocreatine (P-creatine), and total adenylates for the entire 24-hour recovery period. ⋯ This sequence of metabolic changes suggested that metabolism was probably not homogeneous throughout the injured segment, and that tissue metabolic rate was depressed for the initial 4 hours after trauma then increased in metabolically active tissue for the remainder of the 24-hour recovery period. This model of spinal cord trauma results in a severe, prolonged ischemia and metabolic injury to the affected tissue. Whether these metabolic changes results from or cause the tissue damage and irreversible paraplegia associated with this type of spinal cord injury remains to be determined.
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Thirty cadaver brains were examined under X 6 to 16 magnification in order to define the microsurgical anatomy of the pineal region, particularly the relationship of the pineal body, posterior cerebral artery, superior cerebellar artery, vein of Galen, basal vein of Rosenthal, internal cerebral vein, straight sinus, bridging vein, the size of the tentorial notch, and the third and the fourth cranial nerves. The infratentorial and supratentorial approaches to the pineal region are compared from the viewpoint of microsurgical anatomy.
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In the annual address, the President of the American Association of Neurological Surgeons reviews the responsibilities and the continued dedication of the members of the Society to the goals of excellence in patient care, education, and investigation. Insistence upon first-class standards of training has not waivered despite cynical impugnment of our motivation. Dividends of advantage to the general welfare can come from assistance in the design of enlightened legislation, in the assessment of the scientific basis and therapeutic value of various procedures, and in the support of rigorous training for neurosurgeons, fostering the development of excellent clinicians as well as investigators.