The transcondylar approach, consisting of lateral suboccipital craniotomy along with removal of the lateral margin of the foramen magnum, the posteromedial one third of the occipital condyle and the arch of the atlas, allows good access to the anterior margin of the foramen magnum and the lower clival areas (the anterior aspect of the medulla oblongata) from below, without retraction of the cerebellum or the brain stem.
This approach was successfully utilized for direct clipping of aneurysms of the vertebral artery and the vertebrobasilar junction.

View full abstract

Microsurgical anatomy of approaches and perforating arteries in the surgery of the basilar artery aneurysm were examined under the operating microscope using 51 cadaveric brains (102 cerebral hemispheres). The operative approaches studied were as follows: 1. Lateral retrocarotid approach, which was via the lateral retrocarotid space (LRCS) located between the posterior communicating artery and the oculomotor nerve. [Lateral to the posterior communicating artery]. 2. Medial retrocarotid approach, which passed through the route between the perforating branches of the posterior communicating artery via the medial retrocarotid space (MRCS) located between the posterior communicating and the internal carotid arteries. [Medial to the posterior communicating artery] 3. The opticocarotid approach was via the opticocarotid space (OCS) located between the optic nerve and the internal carotid artery.
The histories of 25 of our own patients, operated on in the past three years, (1987-1989) were also reviewed with special reference to the approaches. Favorable outcome (excellent 14, good 4, fair 3) was obtained in 21 cases (84%). Unfavorable outcome, found in 4 cases (poor 2, death 2), was due to the occlusion of the arteries, including perforating branches, and was not related to the difference of the various approaches.
Preservation of the perforators is important and avoids the morbidity and mortality due to surgical procedure in this region, leading to successful results.

View full abstract

In the surgery of the basilar top aneurysm, the internal carotid artery is often retracted to obtain a clear surgical field, which may lead cerebral ischemia. To prevent this the followings are noted: 1. The cross circulation especially through the anterior communicating artery is estimated before surgery, 2. The internal carotid artery is retracted at the elastic, less arteriosclerotic portion, 3. Cerebral protecting agents are administered, 4. A time keeper is arranged, 5. The duration of retraction is basically five minutes, 6. The regional cerebral blood flow and the EEG are monitored, 7. The retraction of the internal carotid artery must be extracted when there is a marked reduction of the regional cerebral blood flow, 8. The retraction of the internal carotid artery must be extracted when the slowing of the EEG is observed.
In this report, a 74-year-old female patient with a basilar top aneurysm associated with a persistent primitive hypoglossal artery is described. The surgery was performed on day 5 after subarachnoid hemorrhage through a pterional approach by retracting the internal carotid artery. A thermal diffusion flow probe was used to monitor the regional cerebral blood flow during surgery. The regional cerebral blood flow was not reduced, or was reduced little, by the retraction of the internal carotid artery, and returned to the level before retraction by the extraction in the early phase. But later, after several retractions, the reduction of the regional cerebral blood flow became rapid by the retraction, and postischemic hyperemia was observed after the extraction. In this case the reduction of the regional cerebral blood flow was not so severe (less than 50%) that the operation could be continued safely, and the aneurysm was clipped successfully. The usefulness and significance of monitoring the regional cerebral blood flow during retraction of the internal carotid artery are discussed.

View full abstract

In two cases of a high basilar (BA) tip aneurysm with a short intracranial internal carotid artery (ICA), a new orbitozygomatic temporopolar approach was carried out. This approach consisted of en block fronto-orbitozygomatic temporal craniotomy and temporopolar access to the aneurysm. The bifurcation of the elongated basilar artery was 20mm in height and the intracranial ICA were 20mm in length and 6mm from the interclinoid line between the anterior and posterior clinoid processes in Case 1, and 18mm and 5mm in Case 2, respectively. The frontotemporal branch of the facial nerve was carefully preserved by subperiosteal and subfascial separation. Bony structures of the lateral and superior orbital wall, the zygomatic arch, the lesser wing, and the temporal bone were removed. In order to access the aneurysm as inferiorly and obliquely as possible through the emptied anterior temporal fossa, the bridging veins from the temporal tip were totally or partially devided. Through the wide working space encircled by the less retracted ICA and the middle cerebral artery, the tentorial hiatus, the oculomotor nerve, the BA aneurysms could be seen easily, and could be successfully clipped by upward and oblique viewing from below. The postoperative clinical course was uneventful in both cases and no cosmetic problem occurred in either.
In this paper, his new operative procedure and its usefulness are presented and compared with other approaches for high BA aneurysms previously described.

View full abstract

Surgical techniques for a combined infratemporal epidural and medial triangle approach to basilar tip aneurysms consists of 1) an orbitozygomatic frontotemporal craniotomy, 2) an infratemporal epidural approach in order to expose the nerve sheathes of the IInd and Ist divisions of the trigeminal nerve and the medial half of the gasserian ganglion, 3) a pterional transsylvian approach for opening the superior wall of the cavernous sinus via the medial triangle and 4) unveiling the cavernous sinus medial to the IInd division of the trigeminal nerve.
Seventeen cases of ruptured basilar tip aneurysms which were operated on via this orbitozygomatic infratemporal transcavernous approach were divided into three groups and the clinical features were reviewed. The fact that out of 4 cases in the early-operation group only one case showed good operative result seems to be attributed to the serious original Hunt and Kosnik Grade of the patients. All 3 cases with Hunt and Kosnik Grades I and II in the relatively early-stage operation group (operated on between Day 6 and Day 10) were good postoperatively. The operative result of 6 out of 8 cases with Grade I or II in the delayed-operation group was good. Conclusion: 1. This transcavernous approach seems to be the preferable approach to the basilar tip aneurysm in the early stage, with several advantages such as 1) wide exposure of the operative field, 2) the shortest possible distance with only slight retraction of the temporal tip with its dura mater, and 3) no division of the Sylvian vein and the spheno-parietal sinus running within the temporal dura propria. 2. Clipping of the basilar tip aneurysm being located either in higher or lower position can be performed successfully without retracting the carotid artery and its tributaries.

View full abstract

Based on our experience with 35 operations using the zygomatic approach for aneurysms on and around the basilar tip, we discuss the advantages, disadvantages, and the indications for this approach. Vertex down positioning of the patient's head, the skin incision just in front of the tragus extending 1.5 cm below the lower border of the zygomatic arch, the cranio-zygomatic osteotomy technique, and multi-directional approach with the rotatable head holder are all demonstrated by video. The bridging vein coming off the temporal lobe tip is cut, and either the anterior temporal or subtemporal route is used to approach the interpeduncular cistern. The posterior communicating artery is elevated in most cases, but working space is also obtained through the perforators coming off this artery. The only disadvantage is that it takes the surgeon 15 to 20 minutes longer than with the conventional craniotomy technique. The advantages of this approach are as follows.
1. The lowest possible supratentorial approach to high placed aneurysms on and around the basilar tip. 2. Working space is wide enough and the clip application is in multiple directions. The zygomatic approach is indicated not only for high placed basilar tip aneurysms, but for large or difficult aneurysms on and around the normal placed basilar tip. This approach, however, is not indicated for low placed basilar tip aneurysms. In the venous phase of angiography, the Rosenthal vein represents a rough configuration of the tentorial edge. In choosing an appropriate surgical approach, how high the tentorial edge is placed is as informative as the distance between the aneurysm neck and the posterior clinoid process.

View full abstract

Surgery of a high basilar bifurcation aneurysm is one of the most difficult operations because of the location. Aneurysms which are located 1.5cm higher than the posterior clinoid process are difficult to approach by the usual pterional or subtemporal approaches. Our original transzygomatic anteriorsubtemporal approach is useful for aneurysms located up to 2 cm higher than the posterior clinoid process. The patient is placed in a semiprone position with the face turned 60°contralaterally. The skin incision is strated from the external auditory meatus. The zygomatic arch is reflected with the temporal muscle. The bone of the middle fossa is removed. The temporal lobe is retracted upwards after dural incision. The tentorial edge, PCA, fourth nerve and third nerve are recognized first. Then we approach the basilar artery and a highly situated aneurysm. In this report, authors explain this useful approach from an anatomical standpoint.

View full abstract

The lower basilar artery aneurysm is one of the most difficult to approach surgically because of its anatomy. The microsurgical anatomy which is encountered while dissecting cadaver specimens with a transpetrosal approah is presented in this paper. The routes used for this approach are 1) subtemporal approach, 2) retrolabyrinthine approach and 3) supra- and infratentorial approach which combines a retrolabyrinthine approach with a retromastoid-posterior subtemporal approach. With this approach, direct visualization of the lower basilar artery and its vicinity are possible with minimum distance and with minimum brain retraction. However, the surgical field is limited and there exists a risk of disturbing the vestibulocochlear function. So, a thorough knowledge of the anatomy of the petrous portion of the temporal bone and skilful drilling of this bone are indispensable. The landmarks which are the most useful for these approaches are the greater petrosal nerve for a subtemporal approach, and anterior margin of the sigmoid sinus, the superior petrosal sinus and the vestibular aqueduct for a retrolabyrinthine approach.

View full abstract

In this paper, technical points of the transpetrosal approach for basilar trunk aneurysms are explained from a microsurgical viewpoint. The most important point is to know the area of bone resection, which is surrounded by the trigeminal impression anteriorly, the eminentia arcuata and internal auditory meatus posteriorly and the major petrosal groove laterally. The bone consistency is an another marking to discriminate the organic part of the petrous bone. Possible surgical complications are cranial nerve palsy of the Vth to VIIIth nerve. Surgical techniques for avoiding these complications are mentioned in the paper.

View full abstract

The case of a 65-year-old man with a ruptured VA-PICA aneurysm located at the midline is reported in this paper. He was admitted complaining of severe headache.
CT scan demonstrated massive subarachnoid hemorrhage, especially around the brain stem. Vertebral angiography showed a right VA-PICA aneurysm, located 4mm to the left from the midline and at lower 1/3 of clivus in height. The dome of the aneurysm projected to the right anteriorly. The aneurysm was approached with a combined subtemporal-transtentorial and lateral suboccipital approach.
The parent artery was reserved through a lateral suboccipital approach and the neck was clipped through a subtemporal transtentorial approach between the petrosal vein and the 7th, 8th nerve.
The combined subtemporal transtentorial and lateral suboccipital approach was advantageous in treating this VA-PICA aneurysm located at the midline and lower 1/3 clivus.

View full abstract

The most significant surgical complication with vertebral artery aneurysms located at or close to the midline is retraction damage to the VIIth to XIIth cranial nerves. From our experience with three patients, we have found the best surgical approach to minimize the cranial nerve injury. The location of the aneurysms related to the jugular tubercle was an important factor for selection of the surgical approach. The procedures we recommend are described below. For aneurysms which are located higher than the level of the jugular tubercle, a posterior transpetrosal approach should be adopted. A lateral suboccipital approach should offer sufficient surgical space for aneurysms which are located on or lower than the level of the jugular tubercle by removal of the jugular tubercle or occipital condyle (transcondyle approach). A transoral transclival approach might be indicated for aneurysms located lower than the level of the jugular tubercle

View full abstract

This report deals with a rare case of fusiform aneurysm of the right vertebral artery associated with left glossopharyngeal neuralgia. A 61-year-old female was hospitalized for severe left pharyngeal pain. Vertebral angiography demonstrated a fusiform aneurysm of the right vertebral artery, which was displaced to the opposite side. On operating, the left posterior inferior cerebellar artery was found to be compressing the left 9th and 10th nerves. Neurovascular compression was associated with a fusiform aneurysm of the right tortuous vertebral artery. The fusiform aneurysm, which looked like a yellowish white, was clipped and microvascular decompression for the left 9th and 10th nerves was accomplished by the left advanced lateral suboccipital approach. Left glossopharyngeal neuralgia disappeared immediately after the operation.
Angiographically, differentiating diagnosis between an atherosclerotic fusiform aneurysm and a dissecting aneurysm is difficult. A fusiform aneurysm suggests not only an atherosclerotic fusiform aneurysm but also a dissecting aneurysm.
An advanced lateral suboccipital approach obtains sufficient operative field without complications. Therefore, the operation for an aneurysm of the vertebral artery should be performed with the advanced lateral suboccipital approach.

View full abstract

Surgical treatment of giant aneurysms is difficult and surgical results are not satisfactory. The authors reviewed the results of our surgery (aneurysmal clipping) of 26 giant aneurysms (internal cerebral artery: 13, anterior cerebral artery: 6, middle cerebral artery: 5, basilar artery: 1, vertebral artery: 1). The outcome of our cases is as follows: good (17), fair (2), poor (1), dead (6). Presenting several representative cases, the authors also described technical aspects of aneurysmal clipping: (1) systemic heparinization should be done to prevent cerebral embolism, when a temporary trapping procedure is used before neck clipping. (2) when the aneurysmal dome is punctured and the neck is clipped, additional clips should be applied to prevent slip-out of the clip first applied on the neck; (3) The technique of retrograde suction decompression of the aneurysm is useful in giant para-clinoidal aneurysms. This permits reflow of blood without any trouble, when it takes a long time to dissect the aneurysmal wall and clip the neck. This technique can be used repeatedly. (4) In cases of partially thrombosed giant aneurysms, thrombectomy makes neck clipping easier.
In addition, one case of large middle cerebral artery aneurysm, which showed hemorrhagic infarction presumably due to hyperperfusion following aneurysmal clipping, was presented. This phenomenon appeared to be similar to the normal perfusion pressure breakthrough phenomenon, which is well known in patients with large arteriovenous malformations

View full abstract

We have experienced four cases of supergiant cerebral aneurysm, each greater than 6.0cm in diameter. Two of these cases were saccular aneurysms of the anterior communicating artery and middle cerebral artery, or which necks were clipped with resection of the aneurysms. Another patient had a fusiform aneurysm of the middle cerebral artery, which was resected accompanied by a reconstructive procedure of cerebral blood flow. The last patient had a fusiform aneurysm of the internal carotid artery. Following internal carotid artery occlusion surgery with superficial temporal artery-middle cerebral artery anastomosis, the aneurysm completely disappeared radiologically within several months. Two cases showed not only focal signs caused by an aneurysmal compression effect but also papilledema caused by intracranial hypertension. The other two cases will also show similar symptoms and signs due to intracranial hypertension in the near future unless adequate surgical treatment is performed. We have, therefore, classified these four cases as supergiant cerebral aneurysms. Although many cases of a giant cerebral aneurysm have been reported in the recent literature, there has been no case of an unruptured giant aneurysm causing increased intracranial pressure, except for our two cases and three other cases.1)3) We think we should select the operative method by which these aneurysms can be made to disappear

View full abstract

The natural history of the intracranial giant aneurysms is not well known. To determine the natural course of the intracranial giant aneurysms, a long term follow-up study was carried ont in a consecutive series of 25 patients with intracranial giant aneurysms who had been followed without surgery. Symptoms and signs directly or indirectly attributable to the intracranial mass effect accounted for presentation in 14 (56%) patients. Three patients (12%) were asymptomatic. Eight patients (32%) presented subarachnoid hemorrhage (SAH). The locations and forms of aneurysms were as follows: extradural (cavernous) internal carotid artery (ICA) in 6 cases; intradural (including ICA, middle cerebral artery and vertebro-basilar artery) saccular form in 17; intradural fusiform in 2.
Subarachnoid hemorrhage was recorded frequently from giant intradural saccular aneurysms. The rupture from giant extradural ICA aneurysms, completely thrombosed giant aneurysms and giant intradural fusiform aneurysms was not recorded. In 50%of partially thrombosed intradural saccular aneurysms, SAH was recorded. Subarachnoid hemorrhage was frequently associated with a poor clinical grading and a high mortality.
In the cases of extradural ICA aneurysms, no dead case was recorded but there was no improvement of mass signs.
The mortality rate in 28 cases was 64%and the major morbidity rate was 20%.
From the results of the presented study, we emphasized that surgical treatment must be recommended whenever possible for cases of giant intradural saccular aneurysms.

View full abstract

1. Transposition of cerebral arteries in aneurysmal surgery was performed in 3 MCA aneurysm cases and one ACA aneurysm and one ACoA aneurysm cases. 2. This technique was effective intense cases whom we had to decide immediately and accidentary to make collateral circulation and complete clipping or trapping through STA could not be used for donor. 3. This method was more effective to obtain enough circulation and simplify in technique and shorten the operation time than STA-MCA anastomosis. 4. Difficulty in technique, for example, deep and nallow field, was the solved problem.

View full abstract

Fifty intracranial vertebral arteries were observed under an operating microscope in order to clarify the originating pattern of small branches. 1) On the average, 3 small branches originated from the intracranial portion of the vertebral artery (VA). Length of the VA distal to PICA origin averaged 16mm. Usually the VA distal to the PICA origin was the main source of such small branches. However, in the case of short distal VA (less than 10mm), more small arteries arose from the VA proximal to the PICA origin.
This finding is clinically useful in determining the occlusion site of to VA for treating unclippable VA aneurysms.
Generally speaking, in order to prevent brain stem ischemia due to occlusion of the VA and its small arteries, the length of the VA distal to the occlusion should be minimized. The occlusion site is influenced by the location of the PICA origin, which is evidenced from a review of previous reports. Based on observation of cadaver brains, it is speculated that, where the VA has a long distal portion, the VA immediately proximal to the PICA origin is the safer site for occlusion to preserve the retrograde blood flow from the contralateral VA at the distal portion where a larger number of the perforators originate.
Where the distal VA portion is short, the VA should be occluded distal to the PICA origin, to preserve blood flow to the proximal portion where more perforators originate.
A VA with no PICA, or on under-developed PICA, may play a major role in blood supply to the brain stem. Therefore, indication of this occluding procedure may be more limited.

View full abstract

Proximal vertebral artery occlusion was performed in eight patients with unclippable vertebral artery or vertebro-basilar junction aneurysms. The initial symptom was subarachnoid hemorrhage in 5 patients, symptoms due to a space-occupying lesion in 2 patients, and cerebral embolism in one patients. In two patients, serious complications were found after operations. A 61-year-old man had cerebral infarction in the area of the posterior cerebral artery and the posterior inferior cerebellar artery (PICA) after vertebral artery occlusion proximal to PICA for a fusiform vertebral aneurysm. A 55-year-old woman had brainstem infarction after operation for a giant vertebro-basilar junction aneurysm. Possible mechanisms of these complications are discussed in this paper.

View full abstract

Dissecting aneurysms are relatively rare in the vertebro-basilar artery system and there is disagreement about the best method of treatment. We experienced a patient in whom subarachnoid hemorrhage occurred again in the 13th year after the initial subarachnoid hemorrhage. A dissecting aneurysm was noted at the vertebro-basilar junction on cerebral angiograms, as reported in this auticle.
The patient was a 53 year old man with a history of a subarachnoid hemorrhage about 13 years ago. On 13 March 1989, there was a sudden onset of headache and vomiting. CT scan indicated a subarachnoid hemorrhage, and cerebral angiography was performed. No abnormalities were noted, except for the slight retention of contrast medium at the vertebro-basilar junction. Since distinct ventricular dilatation was noted after several days, ventricular drainage was performed. When vertebral angiography was performed again after about one week, cerebral vasospasm was noted, and the site of the previous minor abnormality was clearer than before. Cerebral angiography suggested a dissecting aneurysm of the vertebro-basilar junction. An operation was performed, but the patient died of postoperative cerebellar hemorrhage and DIC. When the cerebral angiograms were re-examined, including those performed about 13 years ago, it was considered that the dissecting aneurysm had been present since that time. Study of the cases reported so far revealed none with a course of 13 years, as in this case.

View full abstract

Fourteen cases of dissecting aneurysm of the vertebral artery are reported in this paper. Of these, twelve were cases of SAH, and two were cases of ischemia. Surgery was performed on the ten cases of SAH, and one of the ischemic cases. Eight of these surgeries were by proximal clip occlusion, two by trapping, and one by coating.
Seven cases that underwent proximal clip occlusion experienced favorable results as GR, and one as MD. Except for one patient that underwent surgery in the acute period, all of these were operated on in the late period.
The one patient who underwent tapping died after surgery due to angiospasm and pulmonary complications. The two patients with SAH, who had not undergone surgery, both hemorrhaged again 6 hours and 18 days after onset, and later died.
It is thought that, because there are cases of dissecting vertebral aneurysm in which hemorrhaging reoccurs in the early stage, surgery at an early stage of the aneurysm, expect for the worst grade, is advisable.

View full abstract

Seventy seven asymptomatic nonruptured aneurysms were detected and treated surgically in 77 patients during these 20 years; 87% were treated in the last 8 years. All aneurysms were found on the conventional cerebral angiograms. Angiography was performed because of a family history of SAH in 16 patients, having other types of cerebrovascular diseases in 11, suffering from intractable headache in 28 and having other central nervous system diseases, such as brain tumors, in 22. Neither mortality nor morbidity was experienced except for one patient whose hemiplegia was aggravated secondary to the cerebral infarction. Long term follow-up studies (maximum 20 years) were done and the survival ratio was evaluated by the KAPLAN-MAIYER method. In the surgically treated groups, the survival ratio was significantly higher in the nonruptured group than in the ruptured group.
It is concluded that the most aggressive and effective approach to the treatment of vasospasms is prophylactic clipping of the aneurysms.

View full abstract

Twenty-one patients underwent surgery for unruptured cerebral aneurysms associated with ischemic cerebrovascular disease between 1980 and 1989. In five patients (group A), extracranial-intracranial (EC-IC) bypass or carotidendarterectomy (CEA) was performed at the same time as aneurysm surgery. In five patients (group B), EC-IC bypass or CEA was performed subsequent to aneurysm surgery. In eleven patients (group C), revascularization was not performed. Two patients in group A had ischemic complications (reversible ischemic neurological deficits, RIND), and one patient in group B had a hemorrhagic complication postoperatively. However no permanent deficit developed in any of these patients. Two of these patients had perioperative problems, one in group A had intraoperative hypocapnia and one in group B had been under medication with an antiplatelet drug preoperatively.
The risk of aneurysm surgery for patients who have indications for cerebral revascularization are greater than for patients without such indication. And the risk of surgical complications is greatest when aneurysm surgery is performed concomitantly with revascularization. One reason may be that the brain of these patients is hypoperfused, and is vulnerable to brain retraction, hypocapnia or hypotention. The other reason may be that the temporary arterial occlusion during revascularization or the change of blood flow after revascularization increases the risk of surgical complications.
We conclude that usually, it may better to perform aneurysm surgery without performing revascularization, and when we perform revascularization at the same time, it is more important to pay careful attention to perioperative management including tender operative manipulation of the brain tissue with proper intraoperative monitoring.

View full abstract

In this paper, the authors report on 9 cases of unruptured cerebral aneurysms associated with intracranial arteriovenous malformations (AVMs), and discuss therapeutic problems of unruptured aneurysms.
The following are our conclusions:
1) The rate of combinations of AVMs and aneurysms is not small. Therefore, precise preoperative neuroradiological examinations should be made to confirm the presence or absence of aneurysms in all patients with cerebral AVMs.
2) We were unable to conclude whether or not unruptured aneurysms associated with AVMs should be operated on. However, no decrease in size of aneurysms following excision of AVMs is one important indication for considering a radical operation for aneurysms.
3) The authors reported one case who suffered retrograde thrombosis of the feeding artery, and developed neurological deficits after radical operation for on unruptured aneurysm of the feeding artery. Timing of radical operation for aneurysms following the excision of AVMs must be carefully considered. When surgical treatment of an aneurysm is intended, special attention should be paid to cerebral circulation following excision of AVMs. When an angiographical finding of stagnant arterial flow of feeding arteries is observed, radical operation for aneurysms should be avoided.

View full abstract

The authors reviewed surgical results of 618 surgically treated patients with intracranial aneurysms. Multiple aneurysms were observed in 106 (20%) patients. In cases of multiple aneurysms, their policy has been to treat all aneurysms, ruptured and unruptured, in a one-stage operation whenever possible. All aneurysms of 92 patients were treated in one-stage operations. Eighty three (90%) patients improved or remained stationary, 6 (7%) deteriorated, 3 (3%) died postoperatively. The cause of deterioration or death were due to cerebral vasospasm, primary brain damage or surgical procedure for ruptured aneurysms. No significant difference was found in comparing the rupture site of the aneurysm or the timing of the operation in each preoperative clinical grade. Furthermore, all patients were classified into three groups according to the location of the aneurysms. Sixty-two patients had unilateral aneurysms including aneurysms in the midline, i.e. anterior communicating artery aneurysms, distal basilar artery aneurysms and/or bilateral pericallosal artery aneurysms (unilateral group), and 30 patients had bilateral aneurysms (bilateral group). Morbidity and mortality in unilateral group was 6% and 3%, while in bilateral group, 7%, 3% respectively. No significant difference was observed in the bilateral group compared with the unilateral group, and surgical results of each group appeared to be satisfactory. Neither death nor deterioration was found attributable to operative procedure when unruptured aneurysms were added to the surgery for ruptured aneurysms in a one-stage operation. These surgical results for 92 cases were similar to the results in the rest of the 526 cases. Based on these results, the one-stage operation is recommended, whenever possible, for patients with multiple aneurysms, even if bilateral craniotomy is needed.

View full abstract

A patient is placed in the semi-Fowler's position, the upper body is elevated 15 degrees and the lower is also elevated 10 degrees from a supine position. The head is fixed with a three-point skull fixation device after being rotated 45 degrees toward the contralateral side.
This head position makes it easy to reach the Willis ring along the sphenoidal ridge with minimum retraction of the brain.
Most aneurysms are found on the main vessels around the Willis ring; looking at the main vessels from the same angle, and dissecting the vessels and the aneurysm in the same direction, one will have better orientation and surgical techniques.
Aneurysms around the Willis ring, including basilar top aneurysm and middle cerebral artery aneurysms, are operated on in the same position and through the same pterional approach.
In addition, neck clipping may be possible even in some contralateral aneurysms with an uilateral pterional approach.
This unilateral pterional approach is especially beneficial in treating cases of multiple aneurysms.
Over one half of all contralateral IC aneurysms and about one third of all contralateral MC aneurysms can be clipped with a unilateral pterional approach.
A contralateral anterior choroidal artery aneurysm cannot be clipped because it is hidden behind the optic chiasma.
In handling a basilar top aneurysm, it is rather easy when the length of the IC to the bifurcation of A₁ and M₁ is long enough, but it is difficult when the IC is arteriosclerotic and not movable, because the space for surgical maneuver is too narrow.

View full abstract

Progress in dialysis treatment has been improving the survival rate of chronic dialysis patients, and then which leading to an increase in the neurosurgical complications of them. One case has been reported in the literature of the successful surgical treatment of a ruptured aneurysm in a chronic dialysis patient. There is no widely accepted method of treatment for such patients.
Three cases of ruptured cerebral aneurysm treated successfully in the acute stage are presented in this paper, two of which we reported in the previous paper. The first case was a 50 year-old male (H-K grade I), the second case was a 38 year-old female (H-K grade IV) and the third case was a 46 year-old female (H-K grade III). All of the three patients underwent a preoperative hemodialysis without use of heparin, and were operated on within 24 hours. Decompressive craniotomy and cisternal drainage were performed to reduce the intracranial pressure during postoperative hemodialysis in the acute stage.
Hemodialysis without hepain, which was performed with continuous addition of mannitol and dialysate with a high sodium content to prevent a decrease in intradialytic plasma osmolarity, was carried out daily to achieve precise body fluid regulation.
Plasma osmolarity, intracranial pressure and level of consciousness remained regular during hemodialysis.
We conclude again here that aneurysmal surgery in the acute stage is possible even in patients on maintenance hemodialysis.

View full abstract

Four hundred sixty-seven patients were treated for cerebral aneurysms between November 1976 and October 1990 in our hospital. Of these, six patients were diagnosed as having intracranial bacterial aneurysms. There were four cases of subarachnoid hemorrhage, one case of subdural hematoma, and one case of cerebral infarction. Of these six cases, five (83%) had a single aneurysm and only one (17%) had four aneurysms. All aneurysms existed on the peripheral side.
All the six cases had valvular disease as an underlying disease, and four of them had complications of endocarditis.
For the treatment of intracranial bacterial aneurysms, there are two types of treatment, one being surgical treatment and the other chemical treatment. From our experience with these six cases, we think it advisable, as a rule, to take surgical treatment as the first choice when the aneurysm comes from bleeding, and chemical treatment as the first choice when the aneurysm is found in an unruptured state. However, in giving treatment, it is necessary to always keep in mind the possibility of underlying heart disease.

View full abstract