Ligation of carotid artery in the neck is a valuable method of treatment for intracranial aneurysm, carotid-cavernous fistula and arteriovenous malformation of the brain. This technique, however, does not provide adequate but safe pressure reduction. To ottain the proper pressure, the method of graded occlusion of the carotid artery with measurement of retinal artery pressure has been utilized particularly among American neurosurgeons.
With Poppen-Blalock clamp and Bailliart ophthalmodynamometer, the author ligated carotid artery in 14 patients except one, on whom the clamp was used but retinal artery pressure was not measured. The selected intracranial lesions were as follows;
Intracranial aneurysm 10 cases
Carotid- cavernous fistula 3 cases
Arteriovenous malformation in the hemisphere 1 case
The clamp was applied on the common carotid in all aneurysm and A V malformation cases, and on the internal carotid in 2 patients out of 3 carotid-cavernous fistula. In the remaining one, the clamp was put on the common carotid and external carotid was ligated simultaneously. The clamp was gradually tightened down keeping the retinal artery pressure down to around 50%.
By the ligation, the retinal artery pressure was reduced variably 31% to 78%, mean being 56%. Partial ligation was done in 2 cases in whom the reduction was 58% and 78% respectively by the gradual closure of the clamp. In asmuch as the former disclosed transient ischemic symptoms at this pressure fall. and the latter revealed such a profound pressure reduction, they were kept 41% and 25% reduction by the partial silk ligature. The reduced pressures were apt to rise postoperatively up to 31% in the mean pressure, ranging from 6 days to 2 years.
Follow up arteriograms in 6 patients obtained within 2 weeks after the operation showed disappearance of aneurysm on the middle cerebral in 1, remarkable collapse of aneurysm on the internal carotid in 1, and no gross change in 5 aneurysms. In the patients of carotid-cavernous fistula, 1 recovery and 1 improvement were resulted. In these effective cases, the pressure reduction ranged 50-64%. In a case of partial ligation which resulted 25% pressure reduction was dead 2 months later due to the rebleeding of the aneurysm.
Complications of the carotid ligature occurred in 2 cases. One was the aneur)·sm patient on whom only the gradual occlusion was carried out. She was tolerated well with Matas test done for 4 days, and uneventful during the clamp closure period. Six hours after the silk ligation, however, she fell into shock state during defecation and when recovered the consciousness, her left extremities were paralyzed. Another one disclosed ischemic symptoms at 67% pressure fall and died 2 days after inspite of removal of the clamp.
The remaining 11 patients have been healthy as long as 5 to 28 months after the operation.
It is, therefore, concluded that the range of 50-64% pressure reduction was considered to be effective Pressure, less than 25% reduction being useless, and 67% fall being danger limit in this series.
It was also impressed that the age was an influencing factor for the occurrence of complications.
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