Histologic studies of the spinal cord following spinal anesthesia

Spinal anesthesia induced in autumn frogs produces histologic changes in the large multipolar cells particularly in the dorsal region of the spinal cord. These changes consist of hydropic swelling, loss of distinct outline, bluish staining of the reticulum, dissolution of the Nissl granules, and disappearance of nuclear structure.These changes are transitory, beginning to regress in six hours after the induction of the anesthesia and disappearing entirely within twenty-four hours. No histologic deviation from the normal is observed twenty-four or more hours after the induction of spinal anesthesia in the autumn frog.Human cords examined twenty-two, thirty-six, ninety-six, 144, 192, and 816 hours after spinal anesthesia show no histologic change from the normal.