A study on histological changes of the intracranial arteries after permanent clipping or ligation. Part I. An experimental study in dogs
Ebina, K.
No Shinkei Geka. Neurological Surgery 8(3): 247-261
1980
ISSN/ISBN: 0301-2603 PMID: 7374904 Document Number: 158744
Neck clipping or ligation is thought to be the most effective treatment of cerebral aneurysm, but there have been a few reports about histological changes of the vascular wall following permanent clipping or ligation. Results of a systemic study by light microscopy of the clipped or ligated arteries in 38 dogs and nontreated arteries in 7 control dogs are discussed. Under general anesthesia, fronto-temporal craniotomy was performed, and the middle cerebral artery near the bifurcation of the internal carotid artery was fully exposed under the surgical microscope. This artery was obliterated with a Yasargil clip in 14 dogs, with a Yasargil clip after electric coagulation in 5 dogs, and with a Ag clip in 12 dogs. Ligation with 7-0 monofilament nylon was performed in 7 dogs. The obliterated arteries were examined histopathologically with longitudinal serial sections at various intervals ranging from 3 days to 2 yr and 6 mo. In all cases, granulation tissue reaction was observed around the clip or the ligature 1 mo. after the procedure. It originated from the adventitial fibroblasts near the clip or the ligature. After 3 mo. following the procedure, the main changes were: concentric intimal thickening toward the lumen in the distal segment and uneven thickening, thicker near the clipped bifurcation in the proximal segment, decrease in smooth muscle cells of the tunica media and disappearance at the end; proliferation of collagen fibers and replacement of the tunica media and elongation of the internal elastic lamina.