Showing papers in "Journal of Neurosurgery in 1966"

The Pathology of Vascular (“Arteriovenous”) Malformations

Abstract: V ASCULAR malformations of the central nervous system have been known for at least three hundred years (Olivecrona and Ladenheim '57), hu t are still surrounded by considerable confusion and associated with a complex classification. Detailed morphologic studies of large numbers of cases are rare. Reviews of the many classifications can be found in the works of Evans and Courville '39, Noran '45, Olivecrona and Ladenheim '57, and Rayno r and Kingman '65. While the relationship of vascular malformations to vascular neoplasms is still less than completely clear (Raynor and Kingman '65), it seems relatively certain tha t arteriovenous malformations are true developmental malformations and not neoplasms (Wolf and Brock '35, Noran '45, Manuelidis '50, Olivecrona and Ladenheim '57, Zttlch '57, Russell and Rubinstein '59, Bailey '61, Kaplan et al. '61, McCormick and Nofzinger '66). Ztilch '57 states tha t the distinction between vascular malformations and vascular neoplasms is difficult, and distinguishes between the two groups on the basis of the autonomous growth seen in the la t ter group. However , as Russell and Rubinstein '59 and others have noted, "in common with the t rue neoplasms, it is clear tha t some [malformations] at least are not static bu t grow and inflict progressive destruct ion on the adjacent bra in ." Noran '45 considered tha t the presence of brain parenchyma between the vessels of the angioma was of "pa ramoun t impor tance" in concluding tha t it is a malformat ion ra ther than a vascular neoplasm. Clearly, however, this does not hold for all malformations, most notably the cavernous angiomas. In spite of these difficulties, one considers the malformations to be distinct from the t rue

Cervical Spondylotic Myelopathy

Abstract: T HE most common cause of progressive spinal cord and nerve root deterioration is chronic cervical disc degeneration. The first complete delineation of the neurological syndrome of cervical spondylosis was made 15 years ago by Brain et al. a The spinal cord is involved in this syndrome only when the vertebral canal is narrow in the sagittal dimension. This crucial factor was demonstrated in surgical observations by Allen, 1 in neuropathological studies by Payne and Spillane, 9 and in radiographic studies by Wolf et al. 13 Although there is a large body of related literature, questions remain in the practical application of this knowledge. In the natural course of the disease does the impairment reach major proportions? Lees and Turner z stated that most of their patients showed symptoms for weeks or months followed by improvement or a static condition. Brain 2 stated that there is a natural tendency for the disease to become arrested, but most of those affected were left with a variable degree of disability. We have had experience with a group in whom the course was not so benign. What are the reliable radiological findings which can be correlated with the neurological picture? This question presents a problem especially when the differential diagnosis includes so-called "degenerative disease" of the central nervous system in older patients with co-existing disc degeneration. What are the relative merits and indications among the surgical approaches available now? This question is complicated by the fact that some part of the disability may be irreversible. Between 1953 and 1964, 199 patients with a diagnosis of cervical spondylotic myelopa thy were admit ted to our hospitals for diagnostic investigations. A review of common diagnoses of spinal cord disorders showed spondylotic cervical myelopathy to be the

Effects of Mechanical Stresses on the Spinal Cord in Cervical Spondylosis: A Study on Fresh Cadaver Material

Abstract: T HE brain stem and spinal cord, from a mechanical point of view, can be regarded as a single unit, securely fastened above and below. During movement, the cervical cord and its dural covering slide upwards and downwards no more than s or 3 mm. within the vertebral canal. Therefore, the cord adopts the length of the spinal canal. When the cervical spinal column is flexed (ventroflexed), the cervical spinal canal elongates and the cord is stretched and lengthened. Extension (dorsiflexion) of the cervical spinal column causes the cord to relax and shorten. Smith 2~

The production of cerebrospinal fluid in man and its modification by acetazolamide.

Abstract: The availability at the National institutes of Heal th of a group of patients undergoing cerebrospinal fluid perfusion chemotherapy for the t rea tment of central nervous system neoplasm afforded the opportunity for the s tudy of spinal fluid production and absorption. I t was further felt that the availability of baseline figures would provide an ideal setting for the investigation of agents reported to affect spinal fluid production. Acetazolamide (Diamox| * a carbonic anhydrase inhibitor, has been advocated for the clinical reduction of spinal fluid production. a,5 However, documentation of the effect has been hindered by lack of controlled data, as well as by variations in route and dosage.l,9,10, TM The following report presents data for human spinal fluid production and its modification by acetazolamide.

Blood supply of cervical spinal cord in man. A microangiographic cadaver study.

Abstract: AMKIE'WICZ 1,2 a n d K a d y i lr de sc r ibed the b l o o d s u p p l y of t h e sp ina l cord in t he 19th c e n t u r y . K a d y i s monog r a p h is de t a i l ed , h i g h l y a c c u r a t e , and illust r a t e d w i th f u l l p a g e d co lo red p la tes . H i s s tud ies h a v e been r e p e a t e d m a n y t i m e s b o t h to conf i rm t h e m a n d to b r i n g t h e knowledge in to t he E n g l i s h a n d F r e n c h l anguages . 5.s,'~ 12,14,16,18,~0.21 Al l i n v e s t i g a t o r s h a v e re l ied upon c o n v e n t i o n a l t e c h n i q u e s w i th t he resu l t t h a t K a d y i ' s few m i s t a k e s h a v e escaped de tec t ion . T h o s e w h o used r a d i o g r a p h y 1~ d id n o t e m p l o y m e t h o d s re f ined enough to d e m o n s t r a t e sma l l vesse ls c lea r ly . W e have t h o u g h t i t w o r t h w h i l e to r e s t u d y the b lood s u p p l y of t h e ce rv ica l co rd us ing b o t h mic rod i s sec t i on a n d m i c r o a n g i o g r a p h y , a n d can now p r o v i d e t h e su rgeon w i t h a more a c c u r a t e d e s c r i p t i o n of t h e a r t e r i e s in th is region.

Results of the treatment of intracranial aneurysms by occlusion of the carotid artery in the neck.

Abstract: O CCLUSION of the cervical portion of the carotid ar tery has been employed since 1885 as a definitive t reatment for intracranial aneurysm. The resultant reduction of intra-arterial pressure is expected to reduce the likelihood of subsequent hemorrhage. The alteration of blood flow characteristics within the aneurysmal sac may encourage thrombosis with organization and fibrosis, which would strengthen the wall or obliterate the sac. Tha t pressure can be reduced effectively in the internal carotid ar tery by proximal internal or common carotid occlusion has been substantiated amply by the works of many authors. However, pressure reductions distal to the bifurcation of the internal carotid ar tery following carotid occlusion in the neck were doubted until Bakay and Sweet '52 measured by direct cannulation the intravascular pressures in distal arteries at craniotomy. They found that the pressure reductions beyond the bifurcation of the internal carotid were equivalent to those obtained in the cervical portion of the carotid immediately distal to the site of occlusion. While late postocclusion studies by direct cammlation and recording have been difficult to carry out, ophthalmodynamometry has provided a practical means of estimating the relative pressure decrements.

A Transcervical Transclival Approach to the Ventral Surface of the Brain Stem for Removal of a Clivus Chordoma

Abstract: B ECAVSr of the surgical inaccessibili ty and resistance to radiotherapy of clivus chordomas, the prognosis for pa t ien ts with this lesion has generally been h o p e l e s s . 4,6,13,16,22,24,2s,31,34,37 Nonsurgical t r e a t m e n t of clivus chordomas with radium the r apy 7 and by stereotact ic placement of y t t r i u m 906o has been repo~ed, but surgical r emova l of the tumor , al though usually incomplete, seems to be the best means of pal l ia t ing clinical symptoms . Previous surgical approaches to clivus chordomas include a t ransseptal sphenoidal route, 3 a t ransnasal r o u t e ) 4 an intraoral excision, 11 a t ransoral approach with resection of the lower jaw and soft palate, 35 a transoral t r anspa la ta l approach, 3s,4~ and a subtemporal or subparieto-occipi tal exposure with tentorial splitting, s,44,4s,57 Because these approaches are so often accompanied by meningeal infection 21,3s and occasionally by serious hemorrhage, 21 an approach through the neck would be more desirable. Dur ing recent studies in our laboratory on the cerebral blood flow in the isolated int racrania l circulation in monkeys, we needed to ligate the basi lar artery. This was accomplished by the anter ior surgical app roach through the clivus described by Whi te and Alb in) s T h e ease with which this procedure was accomplished when aided by microins t rumenta t ion (Zeiss dissecting microscope) suggested a possible clinical use. Accordingly, we invest igated the possibility of a similar t ranscl ival operation in man by dissecting 33 cadavers and by anatomical observat ions in living pat ients during radical neck operations for cancer. These prelimin a r y studies enabled us to remove a clivus chordoma employing a transcervical exposure of the clivus through a re t ropharyngeal app roach which has not to our knowledge been previously a t tempted .

Intrasellar Epithelial Cysts

Abstract: HE subject of cystic lesions in, around, and above the sella turcica has at times been confusing from the standpoint of the neurosurgeon, who is particularly concerned with the nature of a lesion at the time of its operative exposure and how radical must be its excision. Cystic adenomas of the pituitary present very little problem. They are usually readily identified, clearly contain tumor tissue and are treated as neoplasms. The delineation of other cysts is sometimes difficult and confusion is compounded by pathological terminology. Thus, the so-called craniopharyngiomatous cyst contains cholesterin crystals, while the cholesteatoma or epidermoid actually contains keratohyalin granules and lacks cholesterin. The term craniopharyngioma, which has gained acceptance, is probably a poor name for this lesion, since Rathke's pouch develops from the stomodeum and not from pharyngeal elements. The major problem which confronts the surgeon and clinical pathologist is that of distinguishing between a craniopharyngioma with cyst formation (hypophysial stalk) and an intrasellar epithelial cyst, which is actually a cyst of the pituitary gland.

Conversion of communicating hydrocephalus to stenosis or occlusion of the aqueduct during ventricular shunt.

Abstract: M ULTIPLE causes of hydrocephalus have long been recognized, ~,5,6,9,12 and the importance of recognizing the etiology in any individual case has been emphasized. 5 Whereas 2 obstruct ive lesions in the cerehrospinal fluid (CSF) sys tem have been demons t ra ted in single cases of hydrocephalus, reports of patients in whom the site of the CSF obstruct ion has shifted during t r e a t m e n t (shunting operation) are rare. 4 In our chronic care program involving a b o u t 200 hydrocephal ic children, periodic evaluat ions have been carried out over the pas t 7 years in an effort to determine the efficacy of the ventriculo-atrial shunt in the control of hydrocephalus as well as to assess the intellectual capaci ty of hydrocephalic children in whom the process has been held in abeyance by chronic shunting of the CSF. A va r i e ty of complications of this prolonged t r e a t m e n t have occurred; on occasion recur ren t septicemia has necessitated rem o v a l of the ventriculo-atrial shunt. In 1 of these cases fractional air s tudy demons t r a t ed only large ventricles; because the original diagnosis had been communicat ing hydrocephalus , a lumbar subarachnoid to u re te r CSF shunt was established. The resul t was nearly fatal . Within 48 hours the re were signs of brain herniation a t the ten tor ia l no tch and a t the cisterna magna. Quick review of the films showed tha t the child no longer had a communicat ing hydrocephalus but ra ther an aqueductal occlusion, d e m o n s t r a t e d on the pneumoencephalogram b u t not correct ly interpreted on the first reading. I m m e d i a t e revision to a ventriculo-

The etiology of acute brain swelling following experimental head injury.

Abstract: T hE pathophysiology of acute head injury has been studied in experimental animals by numerous investigators. Occasionally cercbrospinal fluid pressure has been recorded, usually from the lumbar subarachnoid space or cisterna magna, and there has been uniform agreement tha t prolonged, severe intracranial hypertension does not occur following experimental concussion. An initial sharp rise in intracranial pressure, concomitant with the blow, has been studied in some detail, but this is quite transient, and any subsequent rise in intracranial pressure has been found to be inconstant and moderate in degree. In contrast to the observations in animals, a marked increase in intracranial pressure secondary to brain swelling is commonly observed in patients with head injuries, and this has been generally a t t r ibuted to the rapid development of cerebral edema. If severe brain swelling occurs, intracranial pressure must increase, but we have been unable to find a previous explanation for the failure to observe significant intracranial hypertension following experimental head injury. In prior experiments we presented evidence that the rise in intracranial pressure produced by expansion of an intracranial mass causes cerebral vasodilatation. The vasodilatation increases cerebral blood volume and produces a further rise in intracranial pressure. As this process continues, a very great increase in intracranial pressure may occur rapidly due to intense cerebrovascular congestion. As the difference between the arterial and intracranial pressures decreases, cerebral blood flow falls, and irreversible cerebrovascular dilatation ultimately occurs due to ischemic vasomotor paralysis, l~ The purpose of this preliminary report of our experience with experimental

Sarcoma: A Possible Late Result of Effective Radiation Therapy for Pituitary Adenoma: Report of Two Cases

Abstract: T h e d e v e l o p m e n t of s a r c o m a following radiat ion t r e a t m e n t is a recognized haza rd . Th i s comp l i ca t ion shou ld be cons ide red w h e n a decision regard ing the m o s t su i t ab l e t r e a t m e n t for p i tu i t a r y a d e n o m a m u s t be made . W e h a v e discovered, a m o n g t he records of p i t u i t a r y a d e n o m a s t r e a t e d a t th is hospi ta l , t h r e e cases in wh ich a fibrosarcoma developed in t h e p a t h of t he x ray beam. We believe t h a t t he occur rence of th i s compl ica t ion is f r equen t enough to m e r i t d iscussion. W e know of 10 p rev ious ly r epo r t ed cases of th i s condi t ion ( T a b l e 1). T e r r y el al. ~4 have descr ibed 3 cases, ve ry s imi la r to our own, t h o u g h w i t h o u t full p o s t m o r t e m examina t i ons . O t h e r au tho r s 7,s'g'lS'21 h a v e desc r ibed 6 cases of acromega ly which deve loped a s a r c o m a in or nea r the sella tu rc ica f rom 7 to 20 yea r s a f t e r r ad i a t i on t r e a t m e n t to t h e p i t u i t a r y . M e r e d i t h et al. 14 have repor ted a case of os teogenic s a r c o m a ar is ing in t he t empora l reg ion of t h e skul l 6 years a f te r irr ad i a t i on of a c h r o m o p h o b e a d e n o m a of t he p i tu i t a ry . A case of ours s imi la r t o th i s is l is ted in T a b l e 1 (E.C.) .

Destruction of the pyramidal tract in the monkey. The effects of bilateral section of the cerebral peduncles.

Abstract: I T HAS become increasingly apparent tha t the \"pyramidal t rac t\"w is not the sole descending neural fiber system concerned with the production of voluntary movement of the skeletal musculature. This idea was brought to our at tention ~5 years ago by Tower. s2 As a result of excellent studies on the destruction of the pyramidal t ract in the monkey, she concluded that , \"al though traditionally, the pyramidal system has been considered the voluntary motor pathway, this is too sweeping. An impressive capacity for voluntary movement survives pyramid section.\" At the time this observation a t t racted relatively little attention, perhaps because of Tower 's previous work on the cat. s' I t is well known tha t the cerebral cortex in the cat is of far less importance in the neural organization of the muscular act ivi ty of tha t animal than is the case in man, and tha t the entire cerebral cortex can be removed bilaterally in the cat without materially affecting the animal 's ability to sit, stand, walk or run. Therefore Tower 's finding tha t de-

Report on the cooperative study of intracranial aneurysms and subarachnoid hemorrhage. 3. Subarachnoid hemorrhage unrelated to intracranial aneurysm and A-V malformation. A study of associated diseases and prognosis.

Abstract: S PONTANEOUS subarachnoid hemorrhage is almost always a dramatic and frequently a catastrophic event. This may explain why subarachnoid hemorrhage (SAH) in years past came to be elevated to the status of a disease entity. Increasing knowledge of the subject and improved diagnostic methods have made it possible to recognize a number of disease processes which may present as subarachnoid hemorrhage. This is an important advance since treatment, prognosis and ultimately, prevention, are dependent upon a specific diagnosis. Statistics on the incidence of various causes of SAH are difficult to acquire. In the reports available, marked variations are encountered and appear to reflect differences in methods of study and in selection of cases. In this paper, the various diagnostic categories of SAH will be reviewed based on the experience of the Cooperative Study in 5836 cases. Special attention will be given to the groups of cases in which SAH is unrelated to aneurysms and arteriovenous malformations. (AVM).

Cerebral Angiography: An Analysis of the Diagnostic Value and Complications of Carotid and Vertebral Angiography in 5,484 Patients

Abstract: O N JULY 7, 19~7, Egas Moniz reported to the Paris Neuro!ogical Society on his researches on arterial encephalography" and its importance in the localization of cerebral tumors. Thereafter, cerebral angiography was used extensively in European countries for diagnosis of tumors, arteriovenous malformations, aneurysms, hematomas, and other lesions. By the year 1934, complications of cerebral angiography were reported by Bodechtel and Wichmann, and in 1938 by Ekstr~m and Lindgren. In North America, the first reports on angiography were made by Turnbull '39, Gross '41, and by List and his co-workers '45. A brief history and survey of the literature oi early angiography can be found in Wickbom's 1948 monograph. Carotid angiography was first performed by exposing the carotid artery in the neck and using temporary ligation. Later the temporary ligation was avoided. The percutaneous method of puncture which contributed to the popularity of angiography was introduced by Loman and Myerson '36 and by Shimidzu '37. Vertebral angiography was done by Moniz et al. '33 by in-

Traumatic hematomas of the posterior cranial fossa.

Abstract: D IAGNOSTIC improvements such as carotid angiography and ul t rasound encephalography plus more effective methods of combat t ing cerebral edema with steroids, hypothermia , and massive decompression, have probably saved m a n y pat ients with supratentor ial intracranial hematomas. However , t r aumat ic hematomas located within the posterior cranial fossa cont inue to escape detect ion for they are not readily demons t ra ted by the new diagnostic studies and all too often are not considered unti l found at autopsy. This s tudy contains da ta on all pat ients seen within the last 12 years a t the Massachuse t t s General Hospi tal with clinically significant verified posterior fossa h e m a t o m a s a t t r ibu ted to t rauma. Tab le 1 shows the 17 cases of t raumat ic inf ra tentor ia l h e m a t o m a tha t have been verified since 1955. The number of cases emphasizes the relat ively infrequent occurrence of such lesions when compared with 344 cases of clinically significant t r aumat ic supratentorial h e m a t o m a s seen in this same period.

The importance of repeated angiography in the treatment of mycotic-embolic intracranial aneurysms.

Abstract: A ANEURYSM caused b y an i n v a d i n g o rga n ism, e i t he r f rom t h e a d j a c e n t t i ssues ou t s i de t he vessel wal l or (as fa r m o r e c o m m o n l y occurs) f rom wi th in , ha s been k n o w n as " m y c o t i c " s ince Os le r 6 f i rs t a p p l i e d t h e t e r m to a case in 1885 to focus a t t e n t i o n on i t s i n f l a m m a t o r y n a t u r e . E p p i n g e r , 3 in his c lass ic m o n o g r a p h on th i s e n t i t y , d i scussed t h e p a t h o g e n e s i s of m y c o t i c a n e u r y s m s of i n t r a v a s c u l a r or ig in wh ich he ca l led " m y c o t i c e m b o l i c " . T h i s is p e r h a p s a m o r e des c r i p t i ve t e r m for t he i n t r a v a s c u l a r v a r i e t y w h i c h we d iscuss in th i s p a p e r . M y c o t i c an e u r y s m s occu r m o s t c o m m o n l y w i th v e g e t a t i ve b a c t e r i a l endoca rd i t i s , e i t he r a c u t e or s u b a c u t e , a n d r a r e l y w i t h s e p t i c e m i a s of o t h e r or igins . E a r l y a c c o u n t s of t he i r occurr ences inc lude t h e r e p o r t of a case of " R h e u m a t i s m " in 1851, 5 a n d in 1869 a case of suba r a c h n o i d h e m o r r h a g e s e c o n d a r y to a r u p t u r e d a n e u r y s m in a p a t i e n t w i t h h e a r t v a l v e v e g e t a t i o n s . 2 A l t h o u g h t h e inc idence of th i s les ion has been r e d u c e d s ince t h e i n t r o d u c t i on of an t i b io t i c s , i t s t i l l a c c o u n t s for ~ .5 4 . 5 % of a l l i n t r a c r a n i a l a n e u r y s m s . 4,7 T h e p u r p o s e of th is p a p e r is to d i scuss t he s igni f icance of r e p e a t e d a n g i o g r a p h y in t he t r e a t m e n t of m y c o t i c i n t r a c r a n i a l a n e u r y s m s as i l l u s t r a t e d b y an u n u s u a l case in wh ich no a n e u r y s m was d e m o n s t r a b l e 1 d a y a f t e r a s u b a r a c h n o i d h e m o r r h a g e . A n a n e u r y s m , 1.5 cm. in d i a m e t e r , was seen s m o n t h s a f t e r t h e h e m o r r h a g e , b u t was n o t seen in an ang lo g r a m done 3 m o n t h s l a t e r .

Aneurysms of the Anterior Communicating Artery and Gross Anomalies of the Circle of Willis

Abstract: T hE various theories of development of aneurysms of the intracranial vessels are well known. Although early investigators thought embolic and inflammatory reactions were impor tant factors in their formation, later workers stressed the probable importance of developmental defects of the media a t sites of branching, supplemented by degenerative changes of the internal elastic membrane. Turnbull ~3 suggested tha t cerebral aneurysms formed as a result of degeneration of the media at sites of inherent weakness of the media as a t points of branching. Forbus 7 concluded, however, that although a small diverticulum may occur a t the site of a medial defect associated with the bifurcation of an artery, an \"anatomical\" aneurysm will not develop while the internal elastic membrane is still intact. He concluded further tha t miliary aneurysms as such are not congenital malformations but are acquired lesions arising from a combination of focal weakness in the vessel wall, secondary to a congenital defect of the media and degeneration of the internal elastic membrane, due to continued overstretching of this membrane. While some 3,4,8 have, in general, supported this theory of the development of aneurysms, others have dissented. Basset t and Lemmen 1 remarked tha t most aneurysms of the cerebral arteries represent vestiges of the primitive circulatory system. I t is now well known tha t the incidence of gross anatomical anomalies of the circle of Willis is high. Approximately 60 years ago, however, Blackburn, 2 finding a t autopsy tha t 5~ per cent of the circles of Willis in a group of psychiatric patients were anomalous, concluded tha t anomalies of the circle of

Evaluation of surgical and spontaneous cerebrospinal fluid shunts by isotope scanning.

Abstract: S URGICAL cerebrospinal fluid (CSF) shunts are f requent ly used to t rea t some types of hydrocephalus and increased int racrania l pressure, s,2~ Rarely , vent r iculo-subarachnoid shunts (fistulas) m a y occur spontaneously . 1s,19,31,34 Ventriculovascular (ventr iculo-atr ial) and ventr iculocisternal shunts are the mos t commonly used surgical methods for short circuiting the CSF. The Nulsen-Spi tz shunt 23 with the subcutaneous Hol te r valve, and the Pudenz shunt 26 with the in t ravascular H e y e r valve are the vent r iculo-vascular devices of choice, while the Torki ldscn operat ion 35-3~ is still the preferred procedure for cisternal shunting. The question of ca the te r pa t ency and function f requent ly arises following establ ishment of a CSF shunt . Obstruct ions m a y occur a t the proximal (vcntricular) or distal (vascular or cisternal) end or in the midportion of a shunt. Occasionally d isplacement of the tubing or fo rmat ion of a cyst m a y block CSF flow. A va r i e ty of mechanical , dye, pneumo-radiographic and isotope tests are available to detect a b lock (Table 1). Tests using palpat ion, 5,23,25 fluid wi thdrawal 24 or pressure measuremen t s ~5 have been proposed. In analogy with D a n d y ' s and Blackfan 's dye studies of hydrocephalus 6,7 phenosulphophthalein has been used by Fincher et al. to s tudy the pa t ency of Torki ldsen shunts. 15 These la t te r authors have also employed pneumorad iography for the same purpose. More recently, radioisotopes have been applied to the s tudy of hydrocephalus. 1131labelled h u m a n serum a lbumin (RIHSA) has been used to s tudy normal and abnormal CSF dynamics b y sample counting, ~,32,3a external probe counting, 2'3 and scanning. 9-~4 These isotopic techniques have been extended quite na tu ra l ly to the s tudy of CSF shunts. Some shunts have been evalua ted by injecting R I H S A into the ventricles and

Angiographic End-Results of Carotid Ligation in the Treatment of Carotid Aneurysm

Abstract: GIOGRXPHIC follow-up studies on patients with intracranial aneurysms treated by carotid ligation have been confusing. 2-s The posterior circle of Willis and posterior communicat ing arteries have no t been regularly visualized. Only a fraction of the patients reported have had postoperat ive angiographic studies. We have made a complete angiographic s tudy of a group of patients who have had cervical carotid ligations, with particular emphasis on filling of the aneurysm via the vertebro-basilar system.

Report on the cooperative study of intracranial aneurysms and subarachnoid hemorrhage. Section II. General survey of cases in the central registry and characteristics of the sample population.

Abstract: F ROM early 1958, until the registering of new cases ended in May 1965, 6368 case reports entered the Central Regist ry of the Cooperat ive Study of Intracranial Aneurysms and Subarachnoid Hemorrhage from ~0 part icipat ing university centers (Table 1). These cases had in common either a history of spontaneous non-traumatic subarachnoid hemorrhage (SAH), or the finding of an intracranial aneurysm or arteriovenous malformat ion (AVM). Each case was reported on a standard set of protocol forms which encompassed some 3080 items of coded information. To these forms were usually appended a narrative summary, reproductions of diagnostic anglograms, copies of operative notes, and pathology reports.