Central nervous system trauma : journal of the American Paralysis Association
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Cent Nerv Syst Trauma · Jan 1987
Conductivity of dorsal column fibers during experimental spinal cord compression and after decompression at various stimulus frequencies.
The effects of spinal cord compression on conduction of dorsal column fibers at various stimulus frequencies were analyzed in pentobarbital anesthetized cats. The responses to L6 dorsal root stimulation at 1 to 500 Hz were recorded from the L2 cord dorsum. The L4 cord segment was compressed gradually until the compound action potential (CAP) at 1 Hz was flat. ⋯ The conduction failure at high stimulus frequency indicates incomplete impairment of spike generation in axons injured by mechanical compression and that these axons can transmit impulses at a low stimulus frequency. High frequency stimulation may be useful for monitoring of the function of the CNS axons. The mechanism underlying the augmentation of CAPs at moderately high stimulus frequency is briefly discussed.
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Cent Nerv Syst Trauma · Jan 1987
Comparative StudyPost-traumatic spinal cord ischemia: relationship to injury severity and physiological parameters.
Alterations in lumbar spinal cord white matter blood flow (SCBF) during the initial 4 hours following contusion injury were examined in cats anesthetized with either dial-urethane or sodium pentobarbital and correlated with changes in cardiovascular parameters (MAP, HR), blood gases (pCO2, pO2), and pH. In the dial-urethane anesthetized cats, the effect of a severe 500 g-cm contusion on SCBF was determined at the center of the injury site vs. an adjacent site 3 mm away. At the injury site, SCBF fell progressively from a pre-injury mean of 13.9 +/- 0.8 (S. ⋯ In addition, a significant difference in SCBF may exist between the injury site and adjacent spinal tissue only a few mm away. No correlation between the increase or decrease in SCBF and change in cardiovascular parameters or blood gases following injury is demonstrable nor does anesthetic choice seem to make a significant difference. Thus, post-traumatic changes in SCBF appear to be due to the elaboration of local mediators for the most part unrelated to concomitant alterations in spinal cord perfusion pressure.