:Acta . _ Ndurochlrurglca

Acta Neurochir (Wien) (1992) 118:91-97

9 Springer-Verlag 1992 Printed in Austria

The Basal Interhemispheric Approach for Acute Anterior Communicating Aneurysms N. Yasui, E. Nathal, H. Fujiwara, and A. Suzuki Department of Surgical Neurology, Research Institute for Brain and Blood Vessels - Akita, Akita, Japan

Summary We reviewed the surgical outcome in 85 patients with ruptured anterior communicating artery (ACoA) aneurysms, who were operated on within 72 hours of onset via a basal interhemispheric (BIH) approach (Group 1, N = 48), or an anterior interhemispheric (AIH) approach (Group 2, N = 37). The age, sex ratio and pre-operative grade (Gr) were similar for both groups. The outcome at the time of discharge was as follows for group 1: excellent or good 88%; fair, 6%; vegetative state, 2% and death 4%. For group 2, it was: excellent or good 78%; fair, 16%; vegetative state, 3%; and death, 3%. A significant correlation between admission grade and outcome was found in both groups. The outcome in group I was better than in group 2 for patients with a Glasgow Outcome Scale (GOS) better than fair (p < 0.07). No patient in group 1 had postoperative anosmia, but nine patients in group 2 became anosmic. The total number of complications was also significantly less in group 1. Our overall mortality rate was 4%. In conclusion, the BIH approach was more beneficial for treating acute ACoA aneurysm.

Keywords: Anterior communicating artery; aneurysm; early surgery; operative approach.

in 196911, a n d was m o d i f i e d as the m i c r o s u r g i c a l anterior i n t e r h e m i s p h e r i c ( A I H ) a p p r o a c h b y I t o in 19828, 9. T h e m o s t beneficial p o i n t o f an I H a p p r o a c h is t h a t it allows a n A C o A a n e u r y s m to be visualized with less b r a i n retraction. H o w e v e r , even with this a p p r o a c h , the extent o f b r a i n r e t r a c t i o n a n d dissection can b e c o m e quite extensive w h e n the a n e u r y s m is l o c a t e d in a high position. F o r this reason, the b a s a l i n t e r h e m i s p h e r i c ( B I H ) a p p r o a c h was d e v e l o p e d a n d r e p o r t e d b y one o f the a u t h o r s (Yasui) in 1987 to minimise o p e r a t i v e i n v a s i o n d u r i n g surgery for A C o A a n e u r y s m s 26. This r e p o r t analyzes the results o f early surgery (less t h a n 72 h o u r s f r o m onset) for A C o A a n e u r y s m s , c o m p a r e s the B I H a n d A I H a p p r o a c h e s to evaluate the effects o f m o d i f y i n g the o p e r a t i v e a p p r o a c h .

Materials and Methods

Introduction

Between January 1985 and December 1990, a total of 143 patients with ACoA aneurysms were operated on at the Research Institute for Brain and Blood Vessels - Akita. Of these, 85 patients had bled

A n a n t e r i o r c o m m u n i c a t i n g a r t e r y ( A C o A ) aneur y s m is the c o m m o n e s t type o f c e r e b r a l a n e u r y s m 22' 30,

Table 1. Summary of Patients

b u t there r e m a i n s m u c h c o n t r o v e r s y as to the best m o d e o f surgical t r e a t m e n t . D i s t u r b a n c e o f b l o o d flow by arterial occlusion ( m a i n l y o f the p e r f o r a t i n g arteries) a n d b r a i n c o n t u s i o n caused b y excessive b r a i n retraction are the m a i n p r o b l e m s to be a v o i d e d , especially in early surgery. A l t h o u g h m a n y o p e r a t i v e a p p r o a c h e s have been d e s c r i b e d 3' 11, 13, 15, is, 21, 29, it is h a r d to find a g o o d one for acute a n d swollen a n d the haemorrhage. The m i c r o s u r g i c a l for A C o A a n e u r y s m s

cases where the b r a i n is t e n d e r o p e r a t i v e field is o b s c u r e d b y i n t e r h e m i s p h e r i c (IH) a p p r o a c h was first r e p o r t e d b y L o u g h e e d

No.

Age Sex (F : M) Grade* 2 3 4 5

Group 1

Group 2

48 34 - 82 (mean: 54) 18:29

37 29 - 76 (mean: 56) 15 : 22

27 13 6 2

17 7 9 4

* Hunt and Kosnik grade.

92

N. Yasui etal.: Basal Interhemispheric Approach for ACoA Aneurysms

within 72 hours before admission, and this group was used in the present study. Excluded were patients with unruptured aneurysms or those admitted more than 72 hours after the onset. The patients were separated in two groups according to the surgical procedure utilized (BIH approach, group 1, N = 48; AIH approach, group 2, N = 37), and the intra-operative complications, morbidity, mortality and outcome of each group was compared. In all patients, the diagnosis of subarachnoid haemorrhage (SAH) was established by CT scanning, and the location of the aneurysm was confirmed by angiography. These diagnostic procedures were performed immediately after the initial neurological examination on admission, and the operation was carried out, 2 - 3 hr after arrival on average. The pre-operative neurological status was evaluated according to the scale of Hunt and Kosnik (H & K) 7. Table 1 summarizes the age, sex, and pre-operative clinical grade of the patients in both groups. The age range was 3 4 - 8 2 years in group 1 and 29 - 76 years, in group 2, with a mean of 54 -4- 10 and 56 • 11 years respectively. There was a slight male predominance in both groups. The majority of the aneurysms were less than 8 mm in size at the time of rupture (Table 2). Most of the patients were operated on during the first 24hr after the initial SAH (77% of the patients in group 1 and 92% of those in group 2, Table 3). Two patients of group 1 rebled in the pre-operative period, during angiography or CT scan evaluation respectively. Both of them suffered deterioration of their neurological grade.

Table 2. Time from Onset of SAH to Admission Time from onset

No. of patients

(hours)

Group 1 no. (%)

Group 2 no. (%)

1 - 12 13 - 24 2 4 - 36 37-48 4 9 - 72

21 (44) 16 (33) 4 (8) 4 (8) 3 (6)

20 ( 5 4 ) 14 (38) 1 (3) 2 (5) 0 -

Total

48 (100)

37 (100)

Multiple Aneurysms Twenty of the 85 patients (24%) had multiple aneurysms (group 1, N = 10; group 2, N = 10). In one patient from group 1 and three patients from group 2, these aneurysms were confined to the anterior cerebral artery and were clipped during the initial surgical procedure. In the remaining patients, clipping of the additional aneurysms was performed at a second operation.

Operative Technique All patients were operated on under continuous ventricular or spinal drainage, and mannitol was used when it was considered necessary. In patients with concurrent cerebral haematoma, surgical evacuation was completed prior to aneurysm clipping. Operations were performed using standard microsurgical techniques by four staff members who were experienced in aneurysm surgery. In all acute procedures, a BIH or AIH approach was randomly selected. The details of the surgical techniques used have been described elsewhere9, 24, 26 For the BIH approach, subperiosteal dissection is extended to the nasion, the supra-orbital foramina are exposed, and the supra-orbital nerves are preserved. The craniotomy is then further extended into the anterior medial part of the frontal base and the nasal bones using a bone chisel. Laterally, the craniotomy extends to just medial to the supra-orbital foramen or notch and then runs down to the nasion (Fig. 1 A). The method of opening the dura differs between the two approaches. In the AIH approach, the dura is incised in the shape of letter W and the superior sagital sinus (SSS) is cut at its anterior end after ligation (Fig. 1 B) to open up the operative field while preserving the frontal bridging veins. In the BIH approach, a small dural incision is made in the mid-basal portion of one side parallel to the SSS (Fig. 1 A), providing an adequate operative field without sacrificing the frontal bridging veins. Extension of the craniotomy to the mid-basal region allows one to approach an aneurysm 1 5 - 20 mm in length and about 20 degrees lower than with the AIH approach. This BIH approach may provide many benefits for the subsequent microsurgery, such as lessening the amount of brain dissection and reducing the distance traversed to get to the aneurysm, as shown in Fig. 2, arrow A and B. Also, there is no tension on the

Table 3. Size of the Aneurysms Size (ram)

No. of patients Group 1 no. (%)

Group 2 no. (%)

8 9 - 12 13-25

30 (63) 16 (33) 2(4)

24 (63) 8 (21) 6(16)

Total

48 (100)

38* (100)

* Including one patient with two ACoA aneurysms.

Fig. 1. Schematic diagram of the operative approaches used for anterior communicating aneurysms. Extent of craniotomy and dural opening are shown. (A) Basal interhemispheric approach; (B) Anterior interhemispheric approach

N. Yasui et al.: Basal Interhemispheric Approach for ACoA Aneurysms

93 tional medical or surgical complications occurring during hospitalization were carefully recorded in this study and none of the patients were discharged until complete stabilization of all their medical and/ or surgical problems. At the time of discharge, the outcome was classified according to the Glasgow Outcome Scale (GOS). The GOS is defined as follows: Grade 1 includes patients who demonstrated complete recovery, Grade 2 is moderate disability with an independent and useful life, Grade 3 is severe disability, Grade 4 is a vegetative state, Grade 5 denotes death.

Statistical Analysis Results for the two groups were compared using Pearson's chisquared test. Results

Intraoperative Complications Premature intraoperative rupture and temporary clipping: W h e n we i n c l u d e d even small b l o o d leakages, 15

Fig. 2. Schematic drawing of the operative approaches for anterior communicating aneurysms. Direction of the operative approach is shown by arrows. (Modified from Microsurgery of Cerebral Aneurysms Atlas by Zentaro Ito, Nishimura and Elsevier, 1985) A Basal interhemispheric approach; B Anterior interhemispheric approach

contralateral frontal lobe, which is covered by falx and convex dura mater, These differences provide a marked reduction in the difficulty of operating, especially in cases of high and/or posterior aneurysms. The additional basal bone flap is fixed in the case of the BIH approach, and then, the defect of the opened frontal sinus is packed with muscle and bone dust mixed with antibiotic and covered with periosteum or galea stitched to the dura according to the method of Pool15. In this way, no facial deformities are produced.

Postoperative Management Postoperative management includes antibiotics, anticonvulsants, and fluid and electrolyte therapy. If vasospasm develops, hyperdynamic therapy is performed under normal blood pressure and blood volume hydroxy-ethyl starch (Hespander| and dobutamine5. Continuous cerebrospinal fluid (CSF) drainage is continued until the 10- 20 th postoperative day. If patients showed progressive ventricular enlargement about three weeks after surgery, a shunting procedure was considered.

Postoperative Examination Postoperative angiography was performed one or two weeks after surgery for confirmation of correct clipping of the aneurysm and evaluation of vasospasm. Recently, the early detection and sequential monitoring of vasospasm has been achieved by transcranial doppler (TCD) and/or cerebral blood flow (CBF) measurements. All addi-

a n e u r y s m s (31%) r u p t u r e d d u r i n g dissection in g r o u p 1, a n d a t e m p o r a r y clip was used for p r o x i m a l a n d distal c o n t r o l o f the p a r e n t vessels in f o u r cases. I n g r o u p 2, 12 a n e u r y s m s r u p t u r e d d u r i n g dissection (32%) a n d t e m p o r a r y occlusion was used in two cases. T o t a l occlusion times r a n g e d f r o m 5 to 11 minutes. T h e final o u t c o m e after i n t r a - o p e r a t i v e r u p t u r e d a n d w h e n a t e m p o r a r y clip was used d i d n o t differ significantly f r o m t h a t for the o t h e r p a t i e n t s in b o t h groups. I n d u c t i o n o f h y p o t e n s i o n was n o t used for the c o n t r o l o f p r e m a t u r e i n t r a - o p e r a t i v e r u p t u r e , n o r was in the n o n - r u p t u r e d cases t e m p o r a r y clipping necessary in order to facilitate dissection o f the a n e u r y s m . Brain contusion: One p a t i e n t f r o m g r o u p 1 h a d a u n i l a t e r a l left f i o n t a l c o n t u s i o n which was d o c u m e n t e d i n t r a - o p e r a t i v e l y , a n d was caused b y the n e u r o - a i r t o m e d u r i n g c r a n i o t o m y . H o w e v e r , the p o s t o p e r a t i v e course o f this p a t i e n t was uneventful.

Postoperative Complications Neurological and general complications: A s u m m a r y o f p o s t o p e r a t i v e c o m p l i c a t i o n s for b o t h g r o u p s is given in T a b l e 4 . T h e m a j o r i t y o f the p o s t o p e r a t i v e n e u r o logical c o m p l i c a t i o n s were caused b y the h a e m o r r h a g e itself a n d its consequences, b u t some p r o b l e m s were a t t r i b u t a b l e to the surgical p r o c e d u r e . In g r o u p 1, one p a t i e n t d e v e l o p e d a p o s t o p e r a t i v e visual field defect which was p o s s i b l y due to c o m p r e s s i o n o f the optic c h i a s m b y the clip. I n g r o u p 2, there were 14 c o m p l i c a t i o n s related to the surgical p r o c e d u r e . N i n e p a t i e n t s d e v e l o p e d p o s t o p e r a t i v e a n o s m i a . T w o p a t i e n t s rebled after the first o p e r a t i o n , a n d in b o t h o f them, as reo p e r a t i o n d e m o n s t r a t e d , the cause was r e g r o w t h o f the

N. Yasui etal.: Basal Interhemispheric Approach for ACoA Aneurysms

94 Table 4. Summary of Postoperative Neurological Complications

Anosmia Visual field defect SIADH Diabetes insipidus Aneurysm rebleeding Brain Oedema Epidural haematoma Subdural haematoma Pneumocephalus Brain abscess Meningitis

Group 1

Group 2

0 1 1 0 0 1 0 0 0 1 5

9 0 0 1 2 3 1 1 1 0 8

tibiotic therapy. In group 2, one patient died of severe meningitis. This patient had multiple aneurysms and his postoperative course was complicated by vasospasm and pneumonia. All these patients had a poor neurological grade on admission. Vasospasm: The overall incidence of vasospasm detected by angiography and/or TCD and CBF measurement was high (83%), but the percentage of patients who developed symptoms related to vasospasm was far lower (38%) (14 patients in group l and 18 patients in group 2). The main clinical manifestations associated with vasospasm were either a focal neurological deficit or a significant change in the level of consciousness in the absence of other demonstrable factors. In all except four cases, the symptoms of vasospam were reversible, and in three of these four patients a low-density area was seen on control CT scans. There was no significant difference between the groups in the incidence or effects of symptomatic vasospasm. Mental function: Three major categories of mental function (consciousness, orientation, and memory) were evaluated in the early postoperative period and at the time of discharge in all patients. In group 1, 34 (83%) patients developed some grade of mental impairment and it persisted in 10 (24%) at the time of discharge. The respective percentages for group 2 were 31 (84%) and 19 (51%), including two patients with Korsakoff syndrome. These two patients both had intracerebral haematomas at the time of the SAH so this syndrome could have resulted from the operative procedure. In the majority of patients, the symptoms gradually improved and eventually disappeared after three to six months. Communicating hydrocephalus: Fifty patients (29 in group 1 and 21 in group 2) developed communicating hydrocephalus which was confirmed by isotype cister-

SIADH = Syndrome of inappropriate secretion of anti-diuretic hormone.

aneurysm from a small unclipped area. Two patients had postoperative intracranial haematomas (one epidural and one subdural) which required surgical evacuation. Another patient developed pneumocephalus after the initial operation and a second surgical procedure had to be performed to close an inadvertly opened frontal sinus. In group 1, there were no complications related to the management of the frontal sinus. The total number of complications was significantly higher in group 2 (p < 0.05). One patient in group 1 became vegitative after status epileptic which was caused by brain abscess. Most of the systemic complications were transient and resolved before discharge, but there were also cases where these complications determined the final outcome. In group 1, one patient suffered an acute myocardial infarction and eventually died of heart failure and gastrointestinal haemorrhage. Another patient had generalized sepsis that could not be controlled by anTable 5. Neurological Grade on Admission and Outcome GOS H & K

Group 1 (BIH approach) 1

2

Group 2 (AIH approach)

3

4

5

Total

2 1 0 0

0 0 1 0

0 0 0 2

27 13 6 2

II III IV V

15 6 1 0

7 6 4 0

Total (%)

25 (52)

17

3

1

2

(35)

(6)

(2)

(4)

H & K = Grading by Hunt and Kosnik's classification. GOS = Glasgow outcome scale.

48

(100)

1 6 4 1 0

2

3

10 2 5 1

4

5

Total

1 1 2 2

0 0 1 0

0 0 0 1

17 7 9 4 37 (100)

11

18

6

1

1

(30)

(49)

(16)

(3)

(3)

N. Yasui et al.: Basal InterhemisphericApproach for ACoA Aneurysms nography, and of these 38 (45% of all patients, 21 in group 1 and 17 in group 2) required shunting procedures. There were no differences between the two groups in this respect.

Surgical Outcome The surgical outcome was assessed at the time of discharge according to the GOS (Table 5). In group 1, 88% of the patients had an excellent or good outcome, 6% had a fair result, 2% had a poor outcome (vegetative state), and the mortality was 4%. In group 2, 78% of the patients had excellent or good results, 16% had a fair outcome, 3 % had a poor outcome, and the mortality was also 3%. The outcome in group 1 was better than in group 2 for patients with a GOS that was better than fair (p < 0.07). A significant correlation between neurologic grade on admission and outcome was found in both groups (p < 0.05). In group 1, patients with pre-operative neurological grades of I-III had a 60% chance of excellent early recovery and a 33 % chance of good early recovery, and the mortality rate was zero. In group 2, the respective percentages were 42%, 50%, and 0%. In contrast, only 63% of the group 1 patients in grades IV-V made a good recovery and 25% died during the early postoperative period. In group 2, among patients with the same grades, 54% had a good recovery, 31% had a fair outcome, and 15% had an adverse postoperative course. We had three fatalities; all these patients were grade V on admission and (as mentioned above) all of them had a complicated postoperative course. The patient who remained in a vegetative state was grade IV pre-operatively. In general, the factors related to a poor outcome (grades 4 and 5 of GOS) were in poor grades on admission, developed vasospasm, had advanced age, sustained gastro-intestinal haemorrhage, acute myocardial infarction, and/or infection. One or more of the former conditions was always present in this subpopulation. There was an overall 4% mortality rate for ACoA aneurysms treated surgically in the acute stage. Discussion

We have been searching for an approach that permits good visualization of all the essential anatomical structures and achieves a low incidence of complications related to the surgical procedure itself. Since 1974, an interhemispheric approach has been used for the treatment of acute ACoA aneurysms at this institution s, 9. It was previously demonstrated that the amount of

95

dissection and retraction of the brain required to obtain an adequate operative field for the ACoA aneurysms was only half as much with the AIH approach when compared with the frontobasal lateral approach 9. This was considered an important advance in treatment of acute cases. Nevertheless, further experience has highlighted various technical problems associated with this procedure. For these reasons, the BIH approach was developed in 1985 in order to solve the problems already mentioned above 26.

Technical Advantages of the BIH Approach The beneficial points of this approach are that it requires less interhemispheric dissection and retraction, the operative field is shallower from the cortex to the ACoA complex, the olfactory nerves are preserved and the subcallosal area can be more easily approached than by the AIH method. Also, the anterior bridging veins are avoided when a unilateral dural incision is made by the BIH approach, because the frontal bridging veins are located more than 30mm above the nasion in most cases and the length of the operative field required is only 16ram 28. Preserving these veins is important because impairment of the frontal venous flow by cutting or damaging the anterior bridging veins will cause postoperative frontal lobe dysfunction. Even if the aneurysm is large, it is not necessary to perform extensive brain retraction. Removal of clots from the subarachnoid space can be easily achieved in the interhemispheric, chiasmatic, and pontine cisterns via the subchiasmatic route. At present, perhaps the only indication for the a priori selection of an AIH approach is a large and anteriorly protruding aneurysm that extends beyond the tuberculum sellae. With these aneurysms, the site of rupture is reached early during the interhemispheric dissection when the BIH approach is used, with a consequent high risk of intra-operative rupture. Though there are disadvantages such as the need for an additional craniotomy and opening of the frontal sinus, no infections or other complications due to this have been experienced so far. Moreover, no facial deformities have been produced in our patients by these additional procedures.

Surgical Management At our institution, early surgery is performed in all patients with ruptured intracranial aneurysms 25' 27, except in cases where there is significant angiographic vasospasm, symptomatic vasospasm, or a medical con-

96 traindication. Even when surgery is performed within a relatively short period after admission, there are still patients who rebleed during pre-operative evaluation. Our overall incidence of early rebleeding was 2.5%. During operation, the main risk is premature rupture of the aneurysm, especially when dissection has not been completed. In these cases, the use of temporary clips has been advocated as a helpful and safe method of facilitating aneurysm dissection 12'14,~8. However the occlusion times reported as being safe vary considerably6, i0, ~9. We use temporary clips only under three conditions: a) when a small aneurysm ruptures and clipping of the neck becomes difficult, b) when the site of rupture is near the aneurysmal neck, and c) when the amount of bleeding is such that suction alone does not suffice to confirm the location of the aneurysmal neck. The maximal occlusion time required was 11 minutes, and there were no complications related to temporary clipping in both groups in this series. Although the rate of premature rupture can be high with early surgery4 (32% in our series), it does not affect the outcome. In only one case was a brain contusion produced during craniotomy in group 1, but, as has already been mentioned, the postoperative course of this patient was uneventful. Postoperative Course

The postoperative course is influenced by the sequelae of SAH and by surgical complications, as well as by the prior clinical condition of the patient< 16. The total number of complications related to the surgical procedure was different in the two groups (Table 4). Patients treated by the BIH approach had fewer complications. This again may be due to the less extensive operation necessary to accomplish the aneurysm clipping. In this respect, special consideration should also be given to postoperative olfactory function. One of the main disadvantages of AIH approach is the high incidence of postoperative anosmia. In this study, the olfactory function after operation was carefully investigated whenever possible and we found that the incidence of postoperative anosmia caused by bilateral olfactory nerve damage was about 30% with the AIH approach (9/30 patients) and zero with the BIH approach (0/36 patients), (Table 4). Efforts to preserve olfactory function were reported by Suzuki et al. 2~ but they also found that more than 40% of their cases showed postoperative anosmia despite having anatomically preserved the olfactory nerves. With the AIH approach, injury to the olfactory nerves usually occurs

N. Yasui et al.: Basal InterhemisphericApproach for ACoAAneurysms during retraction of both frontal lobes to obtain a good view of the ACoA complex. At that time, the nerves are displaced laterally and the risk of avulsion is high. In contrast, the BIH approach has two factors which help to avoid nerve damage. One is the lesser amount of retraction required in comparison with the AIH approach, and the other is that only one side is used in the approach. In fact, the possibility of nerve injury does exist with the BIH approach, but since only one nerve is damaged smell is conserved by the intact nerve on the non-operated side. We consider that this is one of the most beneficial points of this approach. In our series, the incidence of symptomatic vastspasm was 38% and the rate of permanent sequelae attributable solely to vasospasm was 5%. There was only one death related to vasospasm, but this patient also had other systemic complications. This suggests that the major danger occurs when vasospasm is combined with complications arising from the surgical procedure and/or postoperative course. In such cases, the morbidity and mortality rate are quite high. A high incidence of abnormal mental function is well recognized after the rupture ofACoA aneurysms22, and ranging from discrete memory defects to a complete Korsakoff syndrome. Although such disturbances may depend on the extent of the SAH, postoperative hydrocephalus, and vasospasm, the surgical procedure is also important in determining the extent of further damage to the frontal lobe and limbic system. Unfortunately, in most of the published series regarding ACoA aneurysms, the incidence of neuropsychological dysfunction has been underreported. Our study suggested that a high percentage of these patients actually develop some degree of mental impairment. The better outcome in group 1 might reflect less brain damage due to the limited amount of dissection required for aneurysm clipping. These preliminary results have prompted us to conduct a prospective study in order to confirm our findings and to clarify the actual influence of the operative procedure itself by assessing patients with a complete battery of neuropsychological tests. So far, the role played by the surgical approach in the incidence of mental disturbances has not been well established. Outcome

The outcome in group 1 was better than in group 2 for the patients with a GOS better than fair. This would seem to be the result of the lesser operative dissection required in the BIH approach. The final outcome of aneurysm surgery is dependent on many

N. Yasui et al.: Basal Interhemispheric Approach for ACoA Aneurysms

factors 2, 16, iv. In our series, the outcome was mainly related to the neurological grade on admission. Patients with SAH who were in grades I-III had a very good chance of a successful outcome, while patients in grade V appear to represent a considerable neurosurgical dilemma, since neither medical nor surgical management seem to offer a good chance of useful survival. Furthermore, in the majority of high-grade cases, the postoperative course is complicated by consequences related to their failure to recover from the effects of the initial haemorrhage. Special consideration is needed in the pre-operative period to decide what will be the real benefits of surgical treatment for these patients, but this is still an unsolved issue 1' 23 References I. Bailes J, Spetzler RF, Hadley MN, Baldwin HZ (1990) Management morbidity and mortality of poor-grade aneurysm patient. J Neurosurg 72:559-566 2. Disney L, Weir B, Grace M (1988) Factors influencing the outcome of aneurysm rupture in poor grade patients. A prospective series. Neurosurgery 23:1-9 3. Fox JL (1979) Microsurgical exposure ofintracranial aneurysms. J Microsurg 1:2-31 4. Gilsbach JM, Harders AG, Eggert HR, Hornyak ME (1988) Early aneurysm surgery. A 7 year clinical practice report. Acta Neurochir (Wien) 90:91-102 5. Hadeishi H, Mizuno M, Suzuki A, Yasui N (1990) Hyperdynamic therapy for cerebral vasospasm. Neurol Med Chir (Tokyo) 30:317-323 6. Jabre A, Symon L (1987) Temporary vascular occlusion during aneurysm surgery. Surg Neurol 27:47-63 7. Hunt WE, Kosnik EJ (1974) Timing and perioperative care intracranial aneurysm surgery. Clin Neurosurg 21:79-89 8. Ito Z (1974) Microsurgical interhemispheric approach for ruptured aneurysms of anterior communicating artery in acute stage. Excerpta Medica 1 CS 418:73 9. Ito Z (1982) The microsurgical anterior interhemispheric approach suitably applied to ruptured aneurysms of the anterior communicating artery in the acute stage. Acta Neurochir (Wien) 63:85-99 10. Ljunggren B, Saveland H, Brandt L, Kagstrom E, Rehncrona S, Nilsson P-E (1983) Temporary clipping during early operation for ruptured aneurysms: preliminary report. Neurosurgery 12: 525 530 11. Lougheed W (1969) Selection, timing and technique of aneurysm surgery of the anterior circle of Willis. Cliu Neurosurg 16: 95113 12. Milhorat TH (1986) On clipping acutely ruptured intracranial aneurysms: a technical note. Surg Neurol 27:47-63 13. Poletti CE (1989) A temporal approach to anterior communicating artery aneurysms. Technical note. J Neurosurg 71: 144146 14. Pool JL (1961) Aneurysms of the anterior communicating artery. Bifrontal craniotomy and routine use of temporary dips. J Neurosurg 18:98-101 15. Pool JL (1972) Bifrontal craniotomy for anterior communicating artery aneurysms. J Neurosurg 36:212-220

97 16. Sengupta RP, McAIlister VL, Kolluri VR (1986) Results of surgical treatment of intracranial aneurysms. In: Sengupta RP, MeAllister VL (eds) Subarachnoid haemorrhage. Springer, Berlin Heidelberg New York Tokyo, pp 237-267 17. Suzuki A, Yasui N, Hadeishi H, Mizuno M, Abumiya T, Sampei T, Nakajima S (1990) Early surgery in elderly patients with ruptured intracranial aneurysms. Neurol Med Clair (Tokyo) 30: 95-99 18, Suzuki J, Kodama N, Ebina T, Koshu K (1979) Surgical treatment of anterior communicating artery aneurysms: from the experience of 346 cases. In: Suzuki J (ed) Cerebral aneurysms. Neuron, Tokyo, pp 238543 19, Suzuki J, Yoshimoto T (1979) The effect of mannitol in prolongation of permissible occlusion time of cerebral arteries: clinical data of aneurysm surgery. In: Suzuki J (ed) Cerebral aneurysms. Neuron, Tokyo, pp 330-337 20. Suzuki J, Yoshimoto T, Mizoi K (1981) Preservation of the olfactory tract following operation on anterior communicating artery aneurysm using bifrontal craniotomy, and its functional prognosis. In: Samii M, Jannetta P (eds) The cranial nerves. Anatomy, pathology, pathophysiology, diagnosis, treatment. Springer, Berlin Heidelberg New York Tokyo, pp 59-65 21. Ya~argil MG, Fox JL, Ray M-V (1975) The operative approach to aneurysms on the anterior communicating artery. In: Krayenbfihl H et al (eds) Advances and technical standard in neurosurgery, Vol 2. Springer, Wien New York, pp 113-170 22. Ya~argil MG (1984) Microsurgery, Vol. II. Thieme, Stuttgart, pp 169-231 23. Yasui N, Kawamura S, Ohta H, Suzuki A, Kamiyama H (1982) Problems of treatment of ruptured aneurysms in acute stage. Analysis of the cases with poor prognosis. Neurol Med Chit (Tokyo) 22[Suppl 1]: 202 24. Yasui N, Ito Z (1983) Microsurgical anterior interhemispheric approach for anterior communicating artery aneurysm. Neurosurgeons (Jpn) 5:113-125 25. Yasui N (1985) Surgical treatment of ruptured cerebral aneurysms in acute stage. In: Sinha KK (ed) Progress in clinical neurosciences, Vol 2. Catholic Press, New Dehli, pp 175-193 26. Yasui N, Suzuki A, Sayama I, Kawamura S (1987) A basal interhemispheric operative approach for anterior communicating artery aneurysms. Neurol Med Chir (Tokyo) 27:756-761 27. Yasui N, Suzuki A, Nemoto M, Asakura K, Nagashima M (1988) Results of the surgical treatment of anterior circulation aneurysms. In: Suzuki J (ed) Advances in surgery for cerebral stroke. Springer, Berlin Heidelberg New York Tokyo, pp 285289 28. Yasui N, Sampei T (1991) Interhemispheric approach for neck clipping of anterior communicating aneurysm. Surgical anatomy for microneurosurgery III: cistern, fissure and sulcus. Sci Med Pup, Tokyo, pp 50-61 29. Yeh H, Tew JM (1985) Anterior interhemispheric approach for aneurysms of the anterior communicating artery. Surg Neurol 23:98-100 30. Yoshimoto T, Kayama T, Kodama N, Suzuki J (1978) Distribution of intracranial aneurysms. Tohoku J Exp Med (Jpn) 126: 125-132 Correspondence and Reprints: Nobuyuki Yasui, M.D., Department of Surgical Neurology, Research Institute for Brain and Blood Vessels, Akita, 6-10 Senshu-kubota-machi, Akita 010, Japan.

The basal interhemispheric approach for acute anterior communicating aneurysms.

We reviewed the surgical outcome in 85 patients with ruptured anterior communicating artery (ACoA) aneurysms, who were operated on within 72 hours of ...
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