EFFECTS OF HYPOPHYSIAL STALK RESECTION ON THE HYPOPHYSIS AND HYPOTHALAMUS OF MAN

Abstract

The hypophysis and hypothalamus in a man of 47 with malignant hypertension, 5 mos. after almost complete surgical interruption of the nerve fibers in the infundibulum and 2 wks. after a unilateral brain hemorrhage, are described. Typical cellular condensation and atrophy of the processus infundibuli occurred just as regularly as those which follow stalk resection in animals. Pars intermedia is not appreciably changed. Fibrosis and reduction of the normal parenchyma of the anterior lobe to about 2/5 of the avg. amt. are directly ascribable to cauterization by the electrosurgical unit used in resecting the stalk. The supraoptic nuclei have only about 15% as many cells as are normally present. The loss of 85% of the cells bilaterally is interpreted as retrograde degeneration resulting from cutting their processes in the infundibular stem, because it is simple degeneration unaccompanied by any significant reaction on the part of the interstitial tissue and because there is no demyelination in the neighborhood. There are at least 100,000 fibers in the infundibular stem of man and they are derived almost wholly from the supraoptic nuclei. In spite of the great diminution in the supraoptico-hypophysial nervous system and alterations in the neuro-hypophysis, no diabetes insipidus resulted, which is in agreement with recent expts. on monkeys where 12 to 16% of this mechanism is sufficient to preserve normal urine output. Apparently some of the large cells of the para-ventricular nuclei have degenerated but the extent of cell loss in this region is uncertain. Outside of the changes ascribable to the hematoma, no other significant brain changes are evident. While the hypertension went down after resection of the hypophysial stalk, the effects on blood pressure of decompression and other factors incident to the operative procedure, together with the early death of the patient, prevent the drawing of any conclusions on this point.