Early management of patients harbouring ruptured aneurysms in posterior fossa is still a major neurosurgical controversy. In this report, we analyze clinical courses and overall management results of 23 patients and discuss possible factors affecting prognosis of treatment. Our surgical policy was as follows: 1) The earliest possible surgical treatment of Grade I and II patients who were hospitalized within the first two days after hemorrhage. 2) All patients with ruptured posterior inferior cerebellar artery (PICA) aneurysms were operated on as early as possible. 3) Operation was delayed in patients harbouring ruptured aneurysms other than PICA, who were classified in Grades III, IV or V. 4) Surgery was delayed for patients in Grades III, IV or V who were admitted later than three days following the ictus. Two were admitted in a moribund state and died without any treatment. Three received aneurysmal neck clippings on the day of admission. Surgical treatment was delayed for the remaining 18. Five of these died preoperatively. Twelve ultimately underwent operations and one received no operation because of the development of thrombosis on the aneurysm. Overall morbidity was 52%, with 33% undergoing surgery. Thirty-nine percent of the morbid cases were able to resume an independent life but nine percent remained dependent. Fifty-four percent of patients receiving surgical treatment resumed an independent life, with 13% being dependent.
Delay of surgery or waiting for an improvement in the clinical states did not provide any additional advantage to offset the risk of high mortality and morbidity after recurrent hemorrhage and vaso-spasm. Moreover, medical complications were major problems in pre- and postoperative management.

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We have experienced 21 cases with ruptured cerebral aneurysms in the posterior circulation during the last 10 years. Nine were male and twelve were female patients. Mean age was 52. We classified these cases into three groups: 1) Basilar artery aneurysms (BA), 2) Aneurysms at the junction of the vertebral and posterior inferior cerebellar arteries (PICA), and 3) fusiform aneurysm of the vertebral artery (VA). Eleven cases were included in the BA group. Nine had aneurysms at the basilar artery summit and two at the junction of the superior cerebellar artery. We performed aneurysm clipping in five cases. Surgery had been done between 8 days through 45 days (mean 22 days) after the SAH attacks. There were two cases with excellent results, two with good results and one with fair. Five out of six non-surgical cases died; three due to severe SAH attack, one due to re-bleeding and one due to respiratory complication. The PICA group comprised eight cases, half of whom had experienced clipping surgery. One case had undergone exceptional surgery on Day 1; while the other three had surgery on Day 8, 13, and 16 respectively. Two had excellent results, one fair and one died (operative failure). All four non-surgical cases died, two due to severe SAH, one due to vasospasm and one due to rebleeding.There were two VA cases. Both had been treated by ligation of the origin of the vertebral artery. Follow-up results were good.
As a rule, we have treated patients with ruptured cerebral aneurysms in the posterior circulation by so-called delayed operation. The surgical results have been good in two thirds of the cases, and the mortality rate was 11%. Two patients died of rebleeding while waiting for radical surgery.
We conclude that early surgery could be considered, especially in good grade cases, to avoid re-bleeding. Development of microsurgical techniques, intraoperative monitoring systems and brain-protective drugs, etc., would make early surgery possible in cases with ruptured aneurysms in the posterior circulation.

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All cases of ruptured aneurysms in the posterior circulation treated in our department over a 19-year period were reviewed to assess relationships between the timing of surgery, preoperative grade, angiographic findings, operative approach and clinical outcome. There were 33 patients, of whom 16 had basilar bifurcation aneurysms, 15 had VA or VA-PICA aneurysms and two had PCA-Pcom aneurysms. The major findings were as follows:
(1) Basilar bifurcation aneurysms. Eleven patients underwent direct operation, three died before surgery and two were treated non-surgically. Overall mortality plus vegetative rate was 44%, and only 38% returned to normal activities. The major causes of poor outcome among the surgical cases were preoperative severe illness (grade 3-4), anatomical difficulties in accessing the aneurysm (high position, posterior projection and large dome) and vasospasm. As for the timing of surgery, the outcome for patients assigned to undergo delayed operation was no better than for those operated on within two weeks after SAH. To improve the operative results, we would choose early operation to prevent rebleeding and facilitate the prophylactic management of the vasospasm.
(2) VA, VA-PICA aneurysm. All of 15 patients underwent direct surgery. Eleven patients returned to normal activities, three could care for themselves and one died. There were six operative morbidity, four IX, X paresis, one VI palsy and one cerebellar ataxia, all of which disappeared completely except for the two IX, X paresis. The larger the dome of the aneurysm, the more operative morbidity we met. Better outcome was obtained by early surgery than when surgery was delayed.

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During the past four years, we have treated 29 patients with ruptured posterior circulation aneurysms. To investigate the outcome of this treatment we divided the patients into three groups; an early surgery group, a delayed surgery group, and a no aneurysmal surgery group. Half of these patients were in very poor condition at admission; so only five patients underwent delayed operation. We operated on 10 patients in the acute stage within 72 hours after the last subarachnoid hemorrhage. The outcome for this early surgery group, evaluated on the Glasgow Outcome Scale, was very excellent compared with the other two groups. After the aneurysmal operation we were able to carry out aggressive antispasm treatment, such as hemodilution, induced hypertension and antiplatelet therapy; therefore, the post-operative course in the early surgery group was better. Factors influencing poor prognosis of patients with ruptured cerebral aneurysms are mainly rebleeding and vasospasm. Particularly in the early stage, prevention of rebleeding is thought to be very important. At present it is controversial whether early or delayed operation is more beneficial for ruptured cerebral aneurysms. However, management of delayed operation is very complicated, and the opportunity to operate may be lost with the development of fatal complications. So we strongly believe that, based on this study, early operation is necessary to improve prognosis, even for patients with ruptured posterior circulation aneurysms.

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Although there has been a trend toward early operation for ruptured aneurysms of the anterior circulation, there have been few reports about early surgery for ruptured vertebro-basilar aneurysms.
In this paper, the result of early surgery was compared with that of delayed surgery and the timing of the operation was discussed for cases with ruptured vertebro-basilar aneurysms.
Operation was performed within seven days after the bleeding in 16 cases (grade I: three cases, II: five cases, III: five cases, IV: three cases) and over eight days in 48 cases (grade I: 29 cases, Ia: 11 cases, III: five cases, IV: three cases).
The overall results indicated that two patients (13%) remained in poor condition, three patients (19%) expired during early surgery, eight patients (17%) were disabled and three patients (6%) died during delayed surgery. Cases of death during early surgery seemed to be frequent, but these patients were in poor condition before the operation (Hunt and Kosnik's grade III: One case, IV: two cases).
When examining the grade I and II cases, only one case with fusiform aneurysm of the vertebral artery, out of eight cases, was in poor condition and no case expired during early surgery. Two cases out of 29 were disabled and one died during delayed surgery.
A good or excellent outcome was obtained in 88% of early surgery cases and 90% in delayed surgery.
Concerning the grade III and IV cases, one out of eight cases was poor and three cases died in early surgery. Four out of eight cases was disabled and one died in delayed surgery.
A good or excellent outcome was obtained in 50% of early surgery cases and 38% of delayed surgery.
Therefore, the overall results viewed from the point of the clinical grade of the patient before the operation are the same for both groups.
From these results it can be seen that early surgery is indicated in cases with ruptured vertebro-basilar aneurysms as in cases with other aneurysms, except for cases with fusiform aneurysms of the vertebral artery.

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Surgery for ruptured vertebrobasilar aneurysms in the acute stage of SAH, when brains are more swollen, is considered to be difficult, since such aneurysms are deep-seated and surrounded by many important perforators, cranial nerves and vital structure. Therefore, delayed surgery is common for these aneurysms.
During the past 5 years, 11 cases with ruptured vertebrobasilar aneurysms have been subjected to delayed operation. The outcome was unfavorable because of a high rate of rebleeding (18%), vasospasm (36%) and hydrocephalus (64%). Recently we performed early operation on three patients (BA-SCA, BA bifurcation, VA-PICA), and the outcome was favorable.
Pre-, intra-, and post-operative management of vertebrobasilar aneurysms subjected to early operation is as follows:
A. Preoperative management
1. sedation and control of blood pressure: intravenous administration of pentazocine, oral administration of nifedipine
2. non-invasive examination digital subtraction angiography using non-ionic water-soluble contrast medium
B. Intraoperative management
1. marking“umbrella”shaped incision line on scalp
2. minimal brain retraction
1) mannitol
2) wide opening of Sylvian fissure
3) gradual removal of CSF
opening of basal cisterns opening of the lamina terminalis ventricular drainage
3. removal of subarachnoid clots
C. Postoperative management
1. cisternal drainage for two weeks
2. hypervolemic, hypertensive therapy for ischemic neurological deficits from vasospasm
In conclusion, early operation can be carried out without many problems for ruptured vertebrobasilar aneurysms.

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Over the past six years we have treated 35 patients with ruptured posterior fossa aneurysms in the acute stage. Thirty-three of the 35 were operated on within four days after the last subarachnoid hemorrhage. Twenty-two patients were operated on within 24 hours. The six month follow-up outcome is excellent in 22 cases, good in four cases and seven patients died. We consider these results favorable (excellent or good) in 79% and unfavorable (poor or dead) in 21%. Compared with our 100 consecutive cases of patients with ruptured anterior aneurysms operated on in the acute stage, we have reached the following conclusions: 1. Early operation for ruptured posterior aneurysms may be more effective in improving the overall management outcome because these aneurysms tend to rebleed more easily during the first 24 hours after the initial SAH and the incident of symptomatic vasospasm is lower than in anterior aneurysms. 2. With recent advances in neurosurgical technique, these small aneurysms (<12mm) can be operated on safely as soon as possible after hemorrhage without specific regard to preoperative grade. But for large aneurysms, or aneurysms in older patients, operation should be performed at least 2-3 days after the hemorrhage.

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Surgical treatment of a vertebral artery aneurysm in the acute stage using temporary clipping of vessels is reported in this paper. The results in twenty-nine cases, including some cases of chronic stage surgery, were 20 excellent, six good, one fair, none poor and two deaths. On the other hand, the results in 13 cases operated on within one week after the onset of symptoms were nine excellent, three good, one fair, none poor and no deaths. Among these, there was no mortality but one case of morbidity. In the morbidity case, motor paresis, caused by the vasospasm in anterior circulation appeared one week after surgery.
In patients with a posterior circulation aneurysm, the incidence of vasospasm, which is the course of unfavorable outcome with severe ruptured aneurysms, is lower. These date are thought to indicate that surgery using temporary clipping may avoid premature rupture during surgery, which is the biggest trouble in acute stage surgery, and bring about favorable surgical result.

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Clipping a vertebrobasilar union aneurysm is one of the most difficult surgical procedures, because it is deep and surrounded by many important structures, such as the brain stem, lower cranial nerves and cerebellum.
We have experienced a successful clipping of the aneurysm at this portion through a transpetrosal-anterosigmoidal approach. We report it and discuss the approaches to aneurysm at this portion.
This approach has many advantages: 1) A small scalp incision. 2) Drilling the posterior pyramis is easy, because the procedure is superficial. 3) Both side of parent artery of the aneurysm can be kept. 4) Little damage to the brain stem, cerebellum and cranial nerves by retractions. 5) Short cut to the aneurysm. 6) A subtemporal approach can be easily combined if it should be required.

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Percutaneous embolization of the parent artery using detachable balloon in three cases of vertebral dissecting aneurysm is reported. These patients were treated within 4 days after subarachnoid hemorrhage following diagnostic angiography. Under local anesthesia, an introducing catheter was positioned into the affected vertebral artery either trans-femorally or trans-axillary. The detachable balloon was situated proximal to the aneurysm and detached after the confirmation of no neurological deficits and good collateral circulation by tolerance test for 15-20 minutes. Cares were taken not to induce rebleeding from the aneurysm. At first, systemic heparinization was not indicated. All procedures were performed in induced hypotension. Intravascular maneuver was limited as seldom as possible. Thrombosis of aneurysm was confirmed either by follow-up angiography or autopsy. Two cases who were grade V (Hunt & Kosnik) at admission died of severe vasospasm. PICA which was proximal to aneurysm was preserved through ipsilateral collateral from ascending cervical to C_1-2 vertebral segmental branch. Detachable balloon occlusion of the vertebral artery for dissecting aneurysm is thought to be less invasive, more indicative and a safer procedure compared to conventional surgical proximal occlusion therapy.

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Techniques for surgical treatment of subarachnoid hemorrhage in the acute stage have recently been developed. But problems still exist in the treatment of aneurysms in the posterior circulation. This paper identifies the cause of the inoperability in patients with basilar aneurysm and its outcome. We have treat 145 cases of basilar aneurysm and we studied 44 cases without direct operation among the 145 cases. The most common reason for not operating on the basilar aneurysm is the rerupture of the aneurysm. Thirty-seven cases (84%) showed subarachnoid hemorrhage from a basilar aneurysm. Rerupture of the basilar aneurysm was observed in seven patients (46%) and this caused the patient to deteriorate. Sixteen patients (96%) died following rerupture of a basilar aneurysm. Only one patient survived but in a vegetative state. Three cases with acute hydrocephalus showed rerupture of the aneurysm directly after ventricular drainage. The second common reason for not operating was severe primary damage due to the first subarachnoid hemorrhage. Nine cases (20%) were too damaged to be operated on, and their outcome was poor. Only one patient recovered almost completely, while others died due to primary subarachnoid hemorrhage. Six cases was not operated on because of the severe complication of age or position of aneurysm. All except one of these cases showed good outcome. Five cases (11%) was not operated on because of severe vasospasm. Problems such as rerupture of aneurysm, primary brain damage following subarachnoid hemorrhage, and vasospasm originate from the first attack of subarachnoid hemorrhage. Rerupture of the aneurysm might be decreased by direct operation in the acute stage. Vasospasm following the attack of subarachnoid hemorrhage might be prevented if the clot of the subarachnoid hemorrhage was removed in the acute stage. Volume expansion, induced hypertension, calcium antagonist or other treatment may decrease the ischemic deficit from vasospasm if direct operation for the aneurysm is performed in the acute stage. Though the high risk of aneurysmal surgery in the acute stage must be recognized, it is worth trying the operation in the acute stage for the treatment of acute hydrocephalus, rerupture, and vasospasm. Two to three percent of unruptured aneurysms per year showed subarachnoid hemorrhage and we heve showed the outcome of unruptured aneurysm surgery is good. It is difficult to decide to operate for an unruptured basilar aneurysm. But we must give more careful consideration to the operation of unruptured basilar aneurysms than to supratentorial unruptured aneurysm. Our results indicate that rerupture of ruptured basilar aneurysms was frequent and the outcome was poor. Direct operation for ruptured basilar aneurysms should be considered in selected patients to prevent rerupture of the aneurysm, vasospasm following an attack of subarachnoid hemorrhage or acute hydrocephalus.

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Basilar artery aneurysms are undoubtedly very difficult to treat. In the past, surgery for a basilar artery aneurysm has been avoided in the acute stage, because it is more difficult and more hazardous than in the chronic stage. However, while waiting for an operation, there have been not a few patients who regress to a serious condition, or die, due to rebleeding or vasospasm. We believe that even with basilar artery aneurysms, it is necessary to clip the aneurysm as early as possible in order to prevent rebleeding, and as much as possible, to remove subarachnoid clots in order to prevent vasospasm.
Total removal of the clots, however, is not only technically impossible, but also sometimes causes brain damage because of the brain retraction. We have already reported that cisternal irrigation therapy with urokinase (UK) and ascorbic acid (AsA) is considered one of the most effective methods to prevent vasospasm.
From these points of view, we have performed surgery in the acute stage (within 72 hours) in the seven cases of basilar aneurysms since 1984. Cisternal irrigation therapy with UK and AsA was used in cases with thick layer subarachnoid clots. Among these seven cases, four were basilar bifurcation aneurysms (BA-bif), two were basilar superior cerebellar artery aneurysms (SCA), and one was a posterior cerebral-posterior communicating artery aneurysm (PCA-Pcom). Two patients were classified as Hunt Kosnik Grade II, three were Grade III, and two were Grade IV. On CT scan, six of the seven cases were in Fisher Group III and their CT numbers were over 60, which suggested a higher probability of vasospasm. Cisternal irrigation therapy with UK and AsA was performed in six of these cases.
In all seven acute surgical cases, no symptomatic vasospasm was found. The outcome was as follows: four cases were ADL 1, two were ADL 2 and one died of cerebral infarction after long term retraction of internal carotid artery. The results of these seven cases were similar to those of 14 chronic surgical cases of basilar artery aneurysms. These results can mean that we do not have to avoid surgery in the acute stage of a basilar artery aneurysm if the case is operable.
Although the number of our cases is still very small, we recommend surgery in the acute stage, even for basilar artery aneurysms. We also recommend to add an effective prevention method for vasospasm, such as the cisternal irrigation therapy with UK and AsA. Surgery in the acute stage may lead to an over-all better outcome for basilar artery aneurysms.

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The indications for early surgery for ruptured basilar artery aneurysms remain controversial, because operative results have not satisfactory enough to date.
Thirty-three cases of ruptured basilar artery aneurysm have been seen during the last 17 years, from 1971 to 1987, in the authors' institute. Twenty-five cases were basilar bifurcation aneurysms and eight were basilar-superior cerebeller aneurysms. Surgical treatment was performed in 19 cases. Only six cases were treated by early operation. Of these, three suffered surgical complications and died. These complications were brain contusion due to severe brain retraction, ischemia or embolism due to direct retraction of the major artery, and injury of perforating arteries. The neck of the aneurysm in these three cases was located in the high portion more than 10 mm above the line between the anterior clinoid process and the posterior clinoid process. The position of the aneurysm seems to be related to the surgical outcome in the basilar artery aneurysm.
Judging from our experience in past surgical cases, the most difficult and important aspect of surgery is achieving a good exposure around the aneurysm through minimal brain retraction, especially in early intervention. For that purpose, the transsylvian approach is considered to be the most effective of several approaches. However, there are some key points to be considered in the transsylvian approach to basilar artery aneurysm, as follows:
1) At craniotomy, the sphenoid wing must be planed sufficiently to get a good exposure. If the aneurysm is located high, either a supraorbital pterional approach or a frontozygomatic approach can provide better exposure.
2) The brain must be shrunken using ventricular drainage and mannitol.
3) The sylvian fissible must be dissected widely.
4) Direct retraction of the major artery must be avoided much as possible except when applying a clip for the aneurysm.
5) The aneurysm must be exposed and dissected not only lateral to the carotid artery but also medial to it.
Recently, several cases have been operated on early following these key points and the result has been a good clinical outcome.

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The outcome of 22 cases of ruptured basilar bifurcation aneurysm (BA-BIF) was divided into three groups and the clinical features were reviewed.
Thirteen cases were classified into two groups according to the timing of surgery and were compared with nine cases who had been followed without surgery.
Significantly fewer cases with“excellent”operative result in the early operation group were found than in the delayed operation group, which seems to be attributable to the serious physiological state (Hunt & Kosnik Grade &) of the patients.
On the other hand, patients who were treated conservatively all died due to rebleeding, between one and 42 days after the episode of first hemorrhage.
Symptomatic vasospasm occurred frequently (over 50%), but proved not to be fatal except in one case of progressive deterioration.
Fatal rebleeding was most often recorded in cases with acute hydrocephalus; and CSF diversion prior to direct clipping seems to be less effective in preventing rebleeding.
The above outcome of nonsurgical cases may justify direct clipping, but the timing of clipping in patients with poor clinical grade can not be clearly clarified in our small surgical series.
In the early stage, a direct operation was performed as late as the following day, using the pterional approach, and when we encountered the aneurysm neck at a high position, it could not be clipped uneventfully. The zygomatic approach seems to be preferable to the BA-BIF in the early stage, particularly when the aneurysm neck is located at a high position, with several advantages such as sufficient exposure of the operative field with slight elevation of P and minimal brain retraction, allowing a successful clipping.

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Twenty-one patients with ruptured infratentorial aneurysms and subarachnoid hemorrhage were surgically treated in the acute stage. There were six fatilities, a mortality rate of 28%, and most being patients with basilar bifurcation aneurysms. Thirteen of the survivors have done well while two are in poor condition. Poor prognosis with death was caused by severe subarachnoid hemorrhage, vasospasm and the injury of perforating arteries. Therefore, we concluded that it was very important to prevent vasospasm postoperatively and to avoid the injury of perforating arteries in acute operation for infratentorial aneurysms.

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The timing of surgery for cerebral aneurysms in the vertebro-basilar system is still controversial. In this paper, we describe our surgical technique for acute surgery for the VA-PICA aneurysm, and also put forward the question of whether we should remove the supratentorial subarachnoidal clot through a new supratentorial craniotomy, after the neck-clipping of the VA-PICA aneurysm, to prevent a delayed vasospasm.
We use a supine-lateral position, the neck is extended and flexed, and incise the skin from 2cm above the inion downward to the level of C4-C5 and 2cm medial to the mastoid process (retroauricular-retromastoidal skin incision). We make a paramastoidal craniectomy, exposing the sigmoid sinus and opening the foramen magnum. We open the dura first at the cistena magna to let the CSF flow out and then extend the dural incision, so as not to injure the cortex of the cerebellum during dural opening.
The PICA comes out through the lower cranial nerves. It is easy to find the origin of the PICA, following its lateral medullary segment. The proximal and distal portions of the vertebral artery are exposed without difficulties if we approach parallel to the posterior surface of the pyramis of the temporal bone. During dissection and clipping of the aneurysmal neck, care must be taken not to injure the hypoglossal nerve, since this nerve usually contacts the aneurysm. After the clipping is finished, we remove as much of the subarachnoidal clot as possible using an irrigation-suction system.
With the suboccipital approach we do not usually place a cisternal drain, in order not to develop a subcutaneous CSF collection. Instead, immeadiate-postoperatively, we place a lumbar drain to remove the bloody CSF. Dural plasty is made using a lyodura.
In the acute surgery of the VA-PICA aneurysm, it is important to make a rather large craniectomy or craniotomy including opening the cisterna magna in order to perform the clipping easer, to remove as much of the subarachnoidal clot as possible and to prevent possible delayed vasospasm.

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It is a standard principle that the ruptured aneurysm must be treated first, then if possible all other aneurysms should be treated in multiple aneurysm case. The same principle is to be applied in cases of a ruptured basilar aneurysm with additional multiple aneurysms.
An ultra-early stage operation for multiple aneurysms including a high position basilar bifurcation aneurysm was reported.
A 58-year-old female was admitted with clouding of consciousness. CT scan revealed severe and wide subarachnoid hemorrhage mainly around the midbrain. Carotid angiography revealed bilateral middle cerebral artery aneurysms. The left vertebral angiography demonstrated a basilar bifurcation aneurysm with high position 18mm distant from the dorsum sellae. A basilar aneurysm was 10mm in diameter, bigger than two other aneurysms. The ruptured aneurysm was thought to be a basilar aneurysm because of it's size and the location of the subarachnoid clot.
The operation was performed 23 hours after the onset using a right fronto-temporal craniotomy. At first the basilar aneurysm was clipped using a subtemporal approach, and then the right middle cerebral artery aneurysm was clipped. Postoperatively cisternal irrigation therapy with ascorbic acid was performed to prevent vasospasm. Symptomatic vasospasm was not observed. Thirteen days after the first operation the left middle cerebral artery aneurysm was clipped. Postoperative course was uneventful without right oculomotor palsy.
Ultra-early surgery for basilar bifurcation aneurysms and the approach to its lesion are discussed in this paper.

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The case of 49-year-old woman with a ruptured dissecting aneurysm of the left vertebral artery is reported in this paper. She was admitted complaining of severe headache and became moribund after re-bleeding attacks. CT scan demonstrated massive subarachnoid hemorrhage, especially around the brainstem, and intraventricular hematoma. Vertebral angiography showed the so-called“string and pearl sign”in the left vertebral artery just distal of the origin of the posterior inferior cerebellar artery and no abnormality in the well-developed right vertebral artery. The aneurysm was located at midline, therefore and advanced lateral suboccipital approach was used. This can be done through the space made by drilling off the lateral part of the foramen magnum. The aneurysm was thus easily trapped without any retraction of the cerebellum. And then extensive clot evacuation was done around the brainstem and in the fourth ventricle. Fortunately, the patient gradually recovered after surgery, but with some mental incapacity. In conclusion, we would like to emphasize that a moribund patient can not be cured without immediately removing the aggravating factors as quickly as possible. And pre-operative diagnosis may be the most important factor in the therapy of dissecting aneurysms.

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[in Japanese]

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