Report on the Cooperative Study of Intracranial and Subarachnoid Hemorrhage SECTION VIII, Part I Results of the Treatment of Intracranial Aneurysms by Occlusion of the Carotid in the Neck HIRO NISHIOKA, M.D.*

Introduction In a late postoperative study of retinal artery CCLUSION of the cervical portion of the pressures in 13 patients with carotid liga- carotid artery has been employed tion, Christiansson '6~ found eight patients O since 1885 as a definitive treatment who had maintained pressure drops of 20 per for intracranial . The resultant re- cent or more over a period of from 1 to 13 duction of intra-arterial pressure is expected years. The observation that there was stasis to reduce the likelihood of subsequent of blood within the aneuwsmal sac after hemorrhage. The alteration of blood flow carotid occlusion was made at characteristics within the aneurysmal sac by Eeker and Riemenschneider '51. During may encourage with organization digital carotid occlusion, they found that and fibrosis, which would strengthen the wall Diodrast remained within the sac for over a or obliterate the sac. That pressure can be minute, and, in the same patient, angiog- reduced effectively in the internal carotid raphy performed one week after partial artery by proximal internal or common ca- occlusion of the common carotid by a tan- rotid occlusion has been substantiated amply talum clip showed no filling of the aneurysm. by the works of many authors. However, Aneurysms may decrease visibly in size or pressure reductions distal to the bifurcation become progressively thrombosed after ca- of the following ca- rotid ligation. Logue (quoted by Ecker and rotid occlusion in the neck were doubted un- Riemenschneider) operated intracranially til Bakay and Sweet '52 measured by direct upon three patients a week after he had cannulation the intravascular pressures in ligated their carotid , and found that distal arteries at craniotomy. They found in each ease, the aneurysm was firm to palpa- that the pressure reductions beyond the bi- tion. Furthermore, needle aspiration yielded furcation of the internal carotid were equiva- no blood. Mount and Taveras '56, and Odom lent to those obtained in the cervical portion eta/. '6~ have reported upon series of late of the carotid immediately distal to the site of postoeelusion angiographic studies, reveal- occlusion. While late postocclusion studies ing either a decrease in size or nonvisualiza- by direct cammlation and recording have been tion of the original aneurysm in a large pro- difficult to carry out, ophthalmodynamom- portion of cases. Mount '59, however, etry has provided a practical means of pointed out the need for caution in inter- estimating the relative pressure decrements. preting nonvisualization of the aneurysm by angiography as a definite sign of thrombosis, Supported by the National Institute of Neurological for one of his patients rebled from an aneu- Diseases and Blindness of the United States Public rysm which had failed to fill postoperatively, Health Service through grants to the Cooperative Study of Intracranial Aneurysms and Subarachnoid even though the parent vessel from which it Hemorrhage. For names of investigators and centers arose was visualized. He noted, further, that participating in this interinstitutional project, see two of his patients bled for the first time after "Contributors and Centers" listed in Section I of the carotid occlusion. report by Sahs et al. in Journal of Neurosurgery, 1966, 24:779-780. Histological investigations by Hassler '63 * Central Registry and Division of Neurosurgery, on the effects of carotid ligation on the circle University of Iowa, Iowa City, Iowa. of Willis of rabbits revealed a change in the

660 Treatment of Intracranial Aneurysms 661 distribution and severity of medial defects uniformly categorized the clinical state of and of intimal cushions as well as an increase their patients at the time of operation, a in the size of the unoccluded carotid artery. feature noticeably lacking from earlier re- The uncertainty regarding the individual de- ports of the results of surgical treatment. gree of protection offered by the procedure Norl6n '5~ reporting on a smaller group of 31 against subsequent aneurysmal rupture, the patients, found a survival of ~3 over a 14- late effects upon the remaining carotid, and year postoperative study. Both he and the possible late ischemic effects which might Mount '59 noted a striking incidence of re- become manifest if and when the remaining current hemorrhage in their cases. In a care- carotid became narrowed or occluded by fully-detailed study of 54 ligated patients, atheroma, plus the morbidity and mortality Itardy et al. '58 noted a survival of 87 per of the procedure itself, have often made cent over 1 to 13 years; three patients died carotid occlusion a treatment of second of recurrent hemorrhage. In a re-evaluation choice or even excluded it altogether from of a series of 35 patients, German and Black the arnmmentarium of many neurosurgeons. '65 found that four of the ~7 survivors first Although the literature of the past ten reported on in 1953 had died in the inter- years has been increasingly concerned with vening decade. One of these patients died newer techniques for intracranial operation, of a ruptured anterior comnmnicating aneu- several reports of large series indicated that rysm (previously undiagnosed) and two in many major centers carotid occlusion is of questionable subaraehnoid hemorrhages. still used extensively in the treatment of The fourth patient died of thrombosis of the . Considerable differ- unligated carotid artery. ences are noted in the results reported from Modifications in technique have been de- these centers. Such disparity would not be signed to reduce the morbidity resulting from expected on the basis of the surgeons' tech- ischemia of the hemisphere ipsilateral to nical skill since the procedure is uniformly carotid occlusion Temporary manual com- simple and applies minimal stress to the pa- pression of the carotid artery (Matas test) tient. Jefferson '51 reported an 86 per cent has given some indication of the adequacy or survival in 14~ ligated patients after one to inadequacy of collateral circulation. How- six years, and Poppen and Fager '60 reported ever, the ability to tolerate such compression a 79 per cent survival in 101 ligated patients for five or ten minutes does not guarantee after I to 15 years. The authors of each report that there will be no ischemic complications specified that the ligations were performed after ligation of the artery, nor does the in- primarily for internal carotid aneurysms. ability to tolerate compression necessarily The majority of the patients in the series of mean that gradual surgical occlusion cannot Poppen and Fager had occlusion of the inter- be performed without . While nal carotid artery and over one-half of them measurements of the reductions in pressure were operated upon more than one month and blood flow may indicate the relative after their subarachnoid hemorrhage. In con- potential for ischemic damage, it has not trast, Mount '59 reporting upon a series of 65 been possible to predict accurately how much patients, 55 of whom received internal carot- pressure or flow decrease may be tolerated by id occlusion or its equivalent (external plus a given individual. The use of intermittent comnmn carotid) at an average interval of 35 digital occlusion prior to ligation to encour- days from the last hemorrhage, achieved sat- age the development of collateral circulation isfactory results in terms of survival and was strongly advocated by Dandy '4~; he function in only 40 per cent; these results also performed two-stage occlusions, par- were disappointing for a series of selected tially occluding the artery in the first stage cases. and totally ligating it later. Of seven patients McKissock et al. '60 reported a survival so treated, none developed ischcmic compli- rate of 72 per cent in s patients with com- cations. The use of adjustable clamps of the mon carotid ligation; in an earlier article, Poppen-Blalock, Selverstone, Crutchfield, McKissock et al. '56 revealed that approxi- and similar type have provided a means of mately 35 per cent of their patients were be- occluding gradually and controllably the ing operated upon within 10 days of their artery over a period of hours or days, and of most recent hemorrhage. These authors have rapidly releasing the occlusion at the bed-