Surgical treatment for aneurysms of the upper basilar artery CHARLES B. WILSON, M.D., AND HOI SANG U, M.D.
Department of Neurological Surgery, University of California School of Medicine, San Francisco, California u,' Fifteen patients with basilar bifurcation arterial aneurysms were treated surgically and their results presented. The importance of preoperative angiographic study to delineate regional anatomy is emphasized. Developments in neuroanesthesia and microsurgical techniques have made possible the successfulattack of these formidable lesions. KEY WORDS basilar aneurysm 9 preoperative angiography intraoperative hypotension 9 microsurgical technique
9
NEURVSMS of the vertebral and basilar reported by Schwartz in 1948.12 With the aid arteries constitute about one sixth of of factors outlined above, surgeons have all intracranial aneurysms. Before the assumed a progressively more aggressive apintroduction of vertebral angiography, these proach to the treatment of vertebral and lesions were diagnosed either after death or basilar aneurysms? .2,1~ Aneurysms at the during the exploration of a posterior fossa basilar bifurcation have been set apart for mass. In cases where surgical correction was separate consideration because of their inattempted, the mortality was prohibitively timate relations to small perforating arteries high, and until recently the general attitude supplying the upper brain stem, a feature favored conservative treatment. Experience umque to aneurysms in this location, a,5 This report reflects the evolution of our exwith the treatment of other intracranial aneurysms has increased our knowledge of perience with the surgical treatment of upper the behavior of bleeding aneurysms and their basilar aneurysms and stresses the imporeffects on the cerebral vascular tree, par- tance of detailed preoperative vertebral ticularly in the period immediately after sub- angiography1,2 and the intraoperative adarachnoid hemorrhage (SAH). At the same juncts of induced hypotension and cerebral time, clinical grades have been established to relaxation. guide the proper timing for surgery." Improved neuroanesthesia, especially induced Clinical Material hypotension, allows intraoperative manipulation of the aneurysm, a critical maneuver reBetween March, 1970, and January, 1975, quired to identify and protect small per- 15 patients with basilar aneurysms have been forating arteries originating from the basilar treated at this institution by one of us (CBW). tip. With one exception, all cases were diagnosed The first successful direct surgical treat- by vertebral angiography during the course of ment of a small posterior fossa aneurysm was investigation for SAH. Preoperative care was
A
J. Neurosurg. / Volume 44 / May, 1976
537
C. B. Wilson and H. S. U similar to that for supratentorial aneurysms. 1 hour and 20 minutes. After the first four In all cases, the approach has been toward cases, moderate hypothermia (31 ~ to 33 ~ C) occlusion of the base of the aneurysm with a was used routinely. We prefer ventricular clip. In situations where either the application drainage to spinal removal of cerebrospinal of a clip was not feasible or the applied clip fluid (CSF) to reexpand the retracted hemidid not approximate the parent artery, the en- sphere and reduce the opportunity for tire lesion was then encased either with development of a postoperative hematoma. muslin (Cases 2, 6, 10, and 15) or with muslin Controlled ventilation was used to maintain and an adhesive (Cases 3, 5, 7, 9, 11, and 13). the pCO~ between 25 and 30 mm Hg. Unless Postoperative angiography was performed in preoperative angiography indicated large ven10 cases. Postoperative angiograms were not tricles that could be drained during surgery, performed in cases treated by reinforcement mannitol was administered to obtain adealone. Five of this latter group of patients quate relaxation of the brain. Two minor modifications of Drake's have been followed from 8 months to 5 years, and in none has there been an indication for technique have seemed advantageous. We prefer skull fixation to produce a motionless angiographic reevaluation. A summary of clinical data in these 15 field. A more anterior approach reduces the patients is given in Table 1. There were seven amount of retraction on the cerebral pedunmen and eight women, with ages ranging cle, and a more anteriorly situated bone flap from 36 to 60 years. Three patients had one can be turned by fashioning a scalp flap based or more additional aneurysms, and one frontally with the inferior limb curving down patient had an associated cerebellar vascular to the zygomatic arch rather than the inmalformation (AVM). With the exception of feriorly based scalp flap preferred by Drake. Case 13 all aneurysms had bled. The single Summary of Cases unruptured basilar tip aneurysm had enlarged and was associated with a new subterminal Figures 1 and 2 show the location of the aneurysm at the time of follow-up angiog- aneurysms in these 15 patients, and Table 1 raphy 2 years after clipping of a ruptured summarizes the surgical methods and postcarotid aneurysm. Two aneurysms bled operative course. before enlarging to present as masses, 7 and 2 Morbidity years later. The interval between SAH and operation is Complications were encountered in the indicated in Table 1. With the exception of early part of this series. Each of the first six Cases 8 and 11, both of which had major patients had one or more complications in neurological deficits caused by giant, partly contrast to the complication-free course of thrombosed aneurysms, all patients were in the last nine patients. Grades I or II at the time of operation. The Two patients (Cases 1 and 3) had postgrading of the patient's clinical status follows operative hematomas requiring evacuation, the classification of Hunt and Hess? one with full recovery and the other with residual but improving hemiparesis. Four Surgical Technique patients (Cases 2, 4, 5, and 6) developed The operative approach followed the hemiparesis in the postoperative period, in procedure described by Drake with only two cases ipsilateral to the side of craniominor modifications? '6 Whenever possible tomy. In all four cases arterial spasm was the aneurysm was approached beneath the documented, in three by angiography and in right temporal lobe. The operating one by direct observation during the course of microscope was used after the dura was reexploration. Two patients (Cases 2 and 5) opened, and sharp dissection with scissors developed postoperative hydrocephalus reand knife blade was used to expose the neck quiring shunting; in one there was the added of the aneurysm. When required for adequate complication of shunt infection. exposure, the tentorium was incised and One patient (Case 6) developed choreiretracted with stay sutures. Hypotension to a form movements in the late postoperative mean pressure of 50 mm Hg was induced period. Although the movement disorder before manipulating the aneurysm. The dura- could be ascribed to vasospasm with infarction of hypotension ranged from 7 minutes to tion, one perforating artery was included in 538
J. Neurosurg. / Volume 44 / May, 1976
Upper basilar artery aneurysms
FiG. 1. Drawings showing the location of aneurysms in Cases 1 to 8.
the clip and we accept this complication as a technical error. Postoperative Condition Table 1 summarizes the results in this series. All patients had a postoperative oculomotor palsy. Except for pupillary dilatation, recovery was complete or nearly so within 3 months. Only two patients failed to achieve binocular vision: in Case 6 the course was complicated by a postoperative left (contralateral) oculomotor palsy, and in Case 11 J. Neurosurg. / Volume 44 / May, 1976
by a long-standing left oculomotor palsy. The patient in Case 5 has binocular vision but with slight residual ptosis. One patient died in the first year after operation. Death was caused by complications following a fractured hip sustained in a fall. Thirteen patients have been followed for 5 months to 5 years. Twelve patients are intellectually intact, eight of them neurologically intact and engaged in their customary activities. Of the four patients who are impaired but ambulatory with mild to moderate hemiparesis, one is employed but 539
C. B. Wilson and H. S. U TABLE 1
Surgical methods, pre- and postoperative course, and results in 15 patients with basilar aneurysms Case No.
Clinical Grade
Interval SAH to Op (days)
Age, Sex
No. of Bleeds
1
39 F
2
III
21
I
Heifetz clip
2
36 F
1
I
30
II
Scoville clip; wrapped with muslin
3
60 F
2
I
16
I
4
36 M
l
II-1II
12
II
Heifetz clip; lat vent CSF drainage; wrapped with hypotension 50 mm Hg X muslin soaked 65 min; intraop arteriogram in methyl methacrylate Heifetz clip lat vent CSF drainage; hypervent; hypotension 50 mm Hg X 55 min
5
46 F
2
II
12
II
muslin in Biobond
hypothermia; CSF drainage; hypotension 55 mm Hg X 1 hr
6
55 F
1
I
14
I
2 clips; muslin to base
LP CSF drainage; hypothermia; hypotension 50 mm Hg • 80 min
7
47 M
1
I
41
I
8
56 M
1
III
Heifetz clip; Biobond to neck thrombectomy
CSF drainage; hypothermia; hypotension 50 mm Hg • 35 min hypothermia
9
55 F
1
I
30
I
10
40 M
1
I
30
I
reinforcement with Biobond and muslin reinforcement with muslin
11
60 F
1
III
LP CSF drainage; hypothermia; hypotension 50 mm Hg X 45 min LP CSF drainage; hypothermia; hypotension 50 mm Hg X 30 min hypothermia 33 ~ C; hypotension 50 mm Hg X 80 min
12
58 M
2
I
13
45 M
1"
I
2 yrs
I
14
47 M
1
I
6
I
15
41F
1
I
19
I
7 yrs
3 yrs
17
Preop Grade
III
III
I
Surgical Method
thrombectomy; Heifetz clip to neck; Biobond reinforcement Yasargil clip
Operative Adjuncts LP and lat vent CSF drainage; hypotension 50 mm Hg • 15 min lat vent CSF drainage; hypotension 50 mm Hg X 45 min
LP CSF drainage; hypothermia; hypotension 50 mm Hg • 1 hr methyl-methaLP CSF drainage; hypothermia; crylate in gauze hypotension 50 mm Hg X 7 min Heifetz clip LP CSF drainage; hypothermia; hypotension 60 mm Hg X 45 rain Heifetz clip; reinforcement with muslin
LP CSF drainage; hypothermia; hypotension 50 mm Hg • 25 min
* Carotid aneurysm previously clipped.
540
J. Neurosurg. / Volume 44 / May, 1976
Upper basilar arterv aneurysms TABLE 1 (Continued)
Postop Course
Postop Angiogram
Results
subdural hematoma on 7th postop day, none full recovery at 5 yrs evacuated, followed by agitation, mild aphasia, It 3rd n. palsy somnolent with right hemiparesis 4 days successful clipping of aneurysm deficits clearing after shunting but also showed hydropostop diagnosed as communicating but patient lost to follow-up cephalus and small rt hydrocephalus; treated with VP shunt subdural hematoma with clearing of deficit incomplete filling of residual mentally clear with residual It rt subdural hematoma; evacuated aneurysm hemiparesis at discharge; later death after hip fracture somnolent; bilat 3rd n. paresis; rt hemiparesis thought to be due to spasm; little effect from therapeutic hypertension arterial spasm and communicating hydrocephalus leading to lethargy and It hemiparesis; CSF shunt complicated by malfunction and infection hypoxia and vasospasm 7th postop day with hemiparesis; pulmonary embolism
successful clipping
mild impairment of memory and mild rt hemiparesis at 3 yrs
aneurysmunchanged
mentally clear; mild It hemiparesis at 1 3A yrs; working as office clerk
residual base
residual rt 3rd n. palsy; It hemiparesis 1 Y2 yrs; It upper extremity choreiform movement treated with thalamotomy intact at 1 JA yrs, full employment
uneventful recovery; polycystic kidney disease discovered on hypertensive work-up mentally cleared but with persistent rt hemiparesis
successful clipping
uneventful recovery
none
uneventful It 3rd n. palsy later cleared
none
complete recovery; returned to work at 1 yr
communicating hydrocephalus treated with LP shunt, rt hemiparesis persistent but improved
none
mentally alert; continuous improvement of rt hemiparesis at 1 yr
residual rt 3rd n. palsy cleared later
successful clipping
fully recovered, back to work at 1 yr
uneventful, rt 3rd n. palsy cleared in 48 hrs
none
fully recovered at 9 mos
communicating hydrocephalus treated with CSF shunt; shunt subsequently removed due to overshunting
mid-basilar trunk and rt internal carotid supraclinoid spasm; successful clipping of aneurysm only base of aneurysm seen
returned to work at 8 mos
partial It 3rd n. palsy
persistence of aneurysm
J. Neurosurg. / Volume 44 / May, 1976
intellectually intact with improved hemiparesis I 1/3 yrs; walking with cane neurologically intact at 1 yr
active but has not returned to work; improving medial rectus weakness at 6 mos
541
C. B. Wilson and H. S. U
F~G. 2. Drawings showingthe location ofaneurysms in Cases 9 to 15.
has mild impairment of memory and slight spasticity of the right limbs. One patient has been lost to follow-up.
Chronologically, all of the first six patients had a complicated course with significant morbidity and sequelae. In contrast, the nine patients treated subsequently have emerged Discussion neurologically intact and eight have resumed Because of the referral pattern to our ser- their customary activities. Drake has delineated the principles for the vice, few patients were admitted in the first 2 weeks after the last SAH. This factor and the operative approach to aneurysms of the basiGrade I or Grade II status of 13 patients in- lar artery? ,e Certain adjuncts are essential dicate the selection exercised in recommend- and others have seemed useful in our hands. ing surgical intervention. Excluding the two In the former category are microscopic Grade III patients with giant aneurysms, the technique, a lax brain achieved by osmotic value of added experience is evident. agents and drainage of CSF, and hypo542
J. Neurosurg. / Volume 44 / May, 1976
Upper basilar artery aneurvsms tension, including modest hyperventilation and hypothermia, during dissection around the aneurysm. A wide array of clips, including Drake's clip with blades especially designed to a c c o m m o d a t e the posterior cerebral artery, should be at hand; for aneurysms that cannot be safely clipped, material for reinforcement must be available. For reinforcing aneurysms we prefer muslin impregnated with Biobond or methyl methacrylate, and we have seen no complications ascribable to the effects of these materials applied directly to neural and vascular tissues. 7,8 We have obtained maximum preoperative information on the aneurysm's morphology and its relationship to parent and adjacent vessels by viewing the aneurysm in multiple projections. Routine posteroanterior, Towne's, and lateral views are studied before obtaining the special views required to visualize the junction of the aneurysm's base with the parent basilar artery. A base view has been particularly informative. Often several projections with different degrees of obliquity are required for precise definition of the lesion. Because of the deep and often prolonged retraction required to expose aneurysms in this location, like Drake we are reluctant to undertake surgery within the first postbleed week and in the presence of arterial spasm. 8 Except in cases with aneurysms presenting because of mass effects, we have not recommended operation for patients in a condition lower than Grade II. Drake proved that basilar aneurysms could and should be treated. Encouraged by his results others have followed Drake's lead with experience similar to our own. In our view, the earlier argument for nonsurgical management of basilar tip aneurysms no longer applies to patients who remain in or achieve a Grade II clinical status. We express our deep appreciation to neurosurgical colleagues who believe, as we do, that uncommon conditions must be collected and described in order to improve results through repetition and to them we are indebted for the patients in this series.
J. Neurosurg. / Volume 44 / May, I976
References I. DeSaussure RL Jr, Hunter E, Robertson JT: Saccular aneurysms of the posterior fossa. J Neurosurg 15:385-391, 1958 2. Dimsdale H, Logue V: Ruptured posterior fossa aneurysms and their surgical treatment. J Neuroi Neurosurg Psychiatry 22:202-217, 1959 3. Drake CG: Further experience with surgical treatment of aneurysms of the basilar artery. J Neurosurg 29:372-392, 1968 4. Drake CG: The surgical treatment of aneurysms of the basilar artery. J Neurosurg 29:436-446, 1968 5. Drake CG: Surgical treatment of ruptured aneurysms of the basilar artery. Experience with 14 cases. J Neurosurg 23:457-473, 1965 6. Drake CG: The surgical treatment of vertebral-basilar aneurysms. Clin Neurosurg 16:114-169, 1969 7. Hammon WM: Intracranial aneurysm encasement. J Neurol Neurosurg Psychiatry 31: 524-527, 1968 8. Hayes G J, Leaver RC: Methyl methacrylate investment of intracranial aneurysms. A report of seven years' experience. J Neurosurg 25:79-80, 1966 9. Hunt WE, Hess RM: Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg 28:14-20, 1968 10. Jamieson KG: Aneurysms of the vertebrobasilar system. Further experience with nine cases. J Neurosurg 28:544-555, 1967 11. Jamieson KG: Aneurysms of the vertebrobasilar system. Surgical intervention in 19 cases. J Neurosurg 21:781-797, 1964 12. Schwartz HG: Arterial aneurysm of the posterior fossa. J Neurosurg 5:312-316, 1948
This work was supported by NINS Training Grant 5593. Address reprint requests to: Charles B. Wilson, M.D., Department of Neurological Surgery, University of California School of Medicine. San Francisco, California 94143.
543
Department of Neurological Surgery, University of California School of Medicine, San Francisco, California u,' Fifteen patients with basilar bifurcation arterial aneurysms were treated surgically and their results presented. The importance of preoperative angiographic study to delineate regional anatomy is emphasized. Developments in neuroanesthesia and microsurgical techniques have made possible the successfulattack of these formidable lesions. KEY WORDS basilar aneurysm 9 preoperative angiography intraoperative hypotension 9 microsurgical technique
9
NEURVSMS of the vertebral and basilar reported by Schwartz in 1948.12 With the aid arteries constitute about one sixth of of factors outlined above, surgeons have all intracranial aneurysms. Before the assumed a progressively more aggressive apintroduction of vertebral angiography, these proach to the treatment of vertebral and lesions were diagnosed either after death or basilar aneurysms? .2,1~ Aneurysms at the during the exploration of a posterior fossa basilar bifurcation have been set apart for mass. In cases where surgical correction was separate consideration because of their inattempted, the mortality was prohibitively timate relations to small perforating arteries high, and until recently the general attitude supplying the upper brain stem, a feature favored conservative treatment. Experience umque to aneurysms in this location, a,5 This report reflects the evolution of our exwith the treatment of other intracranial aneurysms has increased our knowledge of perience with the surgical treatment of upper the behavior of bleeding aneurysms and their basilar aneurysms and stresses the imporeffects on the cerebral vascular tree, par- tance of detailed preoperative vertebral ticularly in the period immediately after sub- angiography1,2 and the intraoperative adarachnoid hemorrhage (SAH). At the same juncts of induced hypotension and cerebral time, clinical grades have been established to relaxation. guide the proper timing for surgery." Improved neuroanesthesia, especially induced Clinical Material hypotension, allows intraoperative manipulation of the aneurysm, a critical maneuver reBetween March, 1970, and January, 1975, quired to identify and protect small per- 15 patients with basilar aneurysms have been forating arteries originating from the basilar treated at this institution by one of us (CBW). tip. With one exception, all cases were diagnosed The first successful direct surgical treat- by vertebral angiography during the course of ment of a small posterior fossa aneurysm was investigation for SAH. Preoperative care was
A
J. Neurosurg. / Volume 44 / May, 1976
537
C. B. Wilson and H. S. U similar to that for supratentorial aneurysms. 1 hour and 20 minutes. After the first four In all cases, the approach has been toward cases, moderate hypothermia (31 ~ to 33 ~ C) occlusion of the base of the aneurysm with a was used routinely. We prefer ventricular clip. In situations where either the application drainage to spinal removal of cerebrospinal of a clip was not feasible or the applied clip fluid (CSF) to reexpand the retracted hemidid not approximate the parent artery, the en- sphere and reduce the opportunity for tire lesion was then encased either with development of a postoperative hematoma. muslin (Cases 2, 6, 10, and 15) or with muslin Controlled ventilation was used to maintain and an adhesive (Cases 3, 5, 7, 9, 11, and 13). the pCO~ between 25 and 30 mm Hg. Unless Postoperative angiography was performed in preoperative angiography indicated large ven10 cases. Postoperative angiograms were not tricles that could be drained during surgery, performed in cases treated by reinforcement mannitol was administered to obtain adealone. Five of this latter group of patients quate relaxation of the brain. Two minor modifications of Drake's have been followed from 8 months to 5 years, and in none has there been an indication for technique have seemed advantageous. We prefer skull fixation to produce a motionless angiographic reevaluation. A summary of clinical data in these 15 field. A more anterior approach reduces the patients is given in Table 1. There were seven amount of retraction on the cerebral pedunmen and eight women, with ages ranging cle, and a more anteriorly situated bone flap from 36 to 60 years. Three patients had one can be turned by fashioning a scalp flap based or more additional aneurysms, and one frontally with the inferior limb curving down patient had an associated cerebellar vascular to the zygomatic arch rather than the inmalformation (AVM). With the exception of feriorly based scalp flap preferred by Drake. Case 13 all aneurysms had bled. The single Summary of Cases unruptured basilar tip aneurysm had enlarged and was associated with a new subterminal Figures 1 and 2 show the location of the aneurysm at the time of follow-up angiog- aneurysms in these 15 patients, and Table 1 raphy 2 years after clipping of a ruptured summarizes the surgical methods and postcarotid aneurysm. Two aneurysms bled operative course. before enlarging to present as masses, 7 and 2 Morbidity years later. The interval between SAH and operation is Complications were encountered in the indicated in Table 1. With the exception of early part of this series. Each of the first six Cases 8 and 11, both of which had major patients had one or more complications in neurological deficits caused by giant, partly contrast to the complication-free course of thrombosed aneurysms, all patients were in the last nine patients. Grades I or II at the time of operation. The Two patients (Cases 1 and 3) had postgrading of the patient's clinical status follows operative hematomas requiring evacuation, the classification of Hunt and Hess? one with full recovery and the other with residual but improving hemiparesis. Four Surgical Technique patients (Cases 2, 4, 5, and 6) developed The operative approach followed the hemiparesis in the postoperative period, in procedure described by Drake with only two cases ipsilateral to the side of craniominor modifications? '6 Whenever possible tomy. In all four cases arterial spasm was the aneurysm was approached beneath the documented, in three by angiography and in right temporal lobe. The operating one by direct observation during the course of microscope was used after the dura was reexploration. Two patients (Cases 2 and 5) opened, and sharp dissection with scissors developed postoperative hydrocephalus reand knife blade was used to expose the neck quiring shunting; in one there was the added of the aneurysm. When required for adequate complication of shunt infection. exposure, the tentorium was incised and One patient (Case 6) developed choreiretracted with stay sutures. Hypotension to a form movements in the late postoperative mean pressure of 50 mm Hg was induced period. Although the movement disorder before manipulating the aneurysm. The dura- could be ascribed to vasospasm with infarction of hypotension ranged from 7 minutes to tion, one perforating artery was included in 538
J. Neurosurg. / Volume 44 / May, 1976
Upper basilar artery aneurysms
FiG. 1. Drawings showing the location of aneurysms in Cases 1 to 8.
the clip and we accept this complication as a technical error. Postoperative Condition Table 1 summarizes the results in this series. All patients had a postoperative oculomotor palsy. Except for pupillary dilatation, recovery was complete or nearly so within 3 months. Only two patients failed to achieve binocular vision: in Case 6 the course was complicated by a postoperative left (contralateral) oculomotor palsy, and in Case 11 J. Neurosurg. / Volume 44 / May, 1976
by a long-standing left oculomotor palsy. The patient in Case 5 has binocular vision but with slight residual ptosis. One patient died in the first year after operation. Death was caused by complications following a fractured hip sustained in a fall. Thirteen patients have been followed for 5 months to 5 years. Twelve patients are intellectually intact, eight of them neurologically intact and engaged in their customary activities. Of the four patients who are impaired but ambulatory with mild to moderate hemiparesis, one is employed but 539
C. B. Wilson and H. S. U TABLE 1
Surgical methods, pre- and postoperative course, and results in 15 patients with basilar aneurysms Case No.
Clinical Grade
Interval SAH to Op (days)
Age, Sex
No. of Bleeds
1
39 F
2
III
21
I
Heifetz clip
2
36 F
1
I
30
II
Scoville clip; wrapped with muslin
3
60 F
2
I
16
I
4
36 M
l
II-1II
12
II
Heifetz clip; lat vent CSF drainage; wrapped with hypotension 50 mm Hg X muslin soaked 65 min; intraop arteriogram in methyl methacrylate Heifetz clip lat vent CSF drainage; hypervent; hypotension 50 mm Hg X 55 min
5
46 F
2
II
12
II
muslin in Biobond
hypothermia; CSF drainage; hypotension 55 mm Hg X 1 hr
6
55 F
1
I
14
I
2 clips; muslin to base
LP CSF drainage; hypothermia; hypotension 50 mm Hg • 80 min
7
47 M
1
I
41
I
8
56 M
1
III
Heifetz clip; Biobond to neck thrombectomy
CSF drainage; hypothermia; hypotension 50 mm Hg • 35 min hypothermia
9
55 F
1
I
30
I
10
40 M
1
I
30
I
reinforcement with Biobond and muslin reinforcement with muslin
11
60 F
1
III
LP CSF drainage; hypothermia; hypotension 50 mm Hg X 45 min LP CSF drainage; hypothermia; hypotension 50 mm Hg X 30 min hypothermia 33 ~ C; hypotension 50 mm Hg X 80 min
12
58 M
2
I
13
45 M
1"
I
2 yrs
I
14
47 M
1
I
6
I
15
41F
1
I
19
I
7 yrs
3 yrs
17
Preop Grade
III
III
I
Surgical Method
thrombectomy; Heifetz clip to neck; Biobond reinforcement Yasargil clip
Operative Adjuncts LP and lat vent CSF drainage; hypotension 50 mm Hg • 15 min lat vent CSF drainage; hypotension 50 mm Hg X 45 min
LP CSF drainage; hypothermia; hypotension 50 mm Hg • 1 hr methyl-methaLP CSF drainage; hypothermia; crylate in gauze hypotension 50 mm Hg X 7 min Heifetz clip LP CSF drainage; hypothermia; hypotension 60 mm Hg X 45 rain Heifetz clip; reinforcement with muslin
LP CSF drainage; hypothermia; hypotension 50 mm Hg • 25 min
* Carotid aneurysm previously clipped.
540
J. Neurosurg. / Volume 44 / May, 1976
Upper basilar arterv aneurysms TABLE 1 (Continued)
Postop Course
Postop Angiogram
Results
subdural hematoma on 7th postop day, none full recovery at 5 yrs evacuated, followed by agitation, mild aphasia, It 3rd n. palsy somnolent with right hemiparesis 4 days successful clipping of aneurysm deficits clearing after shunting but also showed hydropostop diagnosed as communicating but patient lost to follow-up cephalus and small rt hydrocephalus; treated with VP shunt subdural hematoma with clearing of deficit incomplete filling of residual mentally clear with residual It rt subdural hematoma; evacuated aneurysm hemiparesis at discharge; later death after hip fracture somnolent; bilat 3rd n. paresis; rt hemiparesis thought to be due to spasm; little effect from therapeutic hypertension arterial spasm and communicating hydrocephalus leading to lethargy and It hemiparesis; CSF shunt complicated by malfunction and infection hypoxia and vasospasm 7th postop day with hemiparesis; pulmonary embolism
successful clipping
mild impairment of memory and mild rt hemiparesis at 3 yrs
aneurysmunchanged
mentally clear; mild It hemiparesis at 1 3A yrs; working as office clerk
residual base
residual rt 3rd n. palsy; It hemiparesis 1 Y2 yrs; It upper extremity choreiform movement treated with thalamotomy intact at 1 JA yrs, full employment
uneventful recovery; polycystic kidney disease discovered on hypertensive work-up mentally cleared but with persistent rt hemiparesis
successful clipping
uneventful recovery
none
uneventful It 3rd n. palsy later cleared
none
complete recovery; returned to work at 1 yr
communicating hydrocephalus treated with LP shunt, rt hemiparesis persistent but improved
none
mentally alert; continuous improvement of rt hemiparesis at 1 yr
residual rt 3rd n. palsy cleared later
successful clipping
fully recovered, back to work at 1 yr
uneventful, rt 3rd n. palsy cleared in 48 hrs
none
fully recovered at 9 mos
communicating hydrocephalus treated with CSF shunt; shunt subsequently removed due to overshunting
mid-basilar trunk and rt internal carotid supraclinoid spasm; successful clipping of aneurysm only base of aneurysm seen
returned to work at 8 mos
partial It 3rd n. palsy
persistence of aneurysm
J. Neurosurg. / Volume 44 / May, 1976
intellectually intact with improved hemiparesis I 1/3 yrs; walking with cane neurologically intact at 1 yr
active but has not returned to work; improving medial rectus weakness at 6 mos
541
C. B. Wilson and H. S. U
F~G. 2. Drawings showingthe location ofaneurysms in Cases 9 to 15.
has mild impairment of memory and slight spasticity of the right limbs. One patient has been lost to follow-up.
Chronologically, all of the first six patients had a complicated course with significant morbidity and sequelae. In contrast, the nine patients treated subsequently have emerged Discussion neurologically intact and eight have resumed Because of the referral pattern to our ser- their customary activities. Drake has delineated the principles for the vice, few patients were admitted in the first 2 weeks after the last SAH. This factor and the operative approach to aneurysms of the basiGrade I or Grade II status of 13 patients in- lar artery? ,e Certain adjuncts are essential dicate the selection exercised in recommend- and others have seemed useful in our hands. ing surgical intervention. Excluding the two In the former category are microscopic Grade III patients with giant aneurysms, the technique, a lax brain achieved by osmotic value of added experience is evident. agents and drainage of CSF, and hypo542
J. Neurosurg. / Volume 44 / May, 1976
Upper basilar artery aneurvsms tension, including modest hyperventilation and hypothermia, during dissection around the aneurysm. A wide array of clips, including Drake's clip with blades especially designed to a c c o m m o d a t e the posterior cerebral artery, should be at hand; for aneurysms that cannot be safely clipped, material for reinforcement must be available. For reinforcing aneurysms we prefer muslin impregnated with Biobond or methyl methacrylate, and we have seen no complications ascribable to the effects of these materials applied directly to neural and vascular tissues. 7,8 We have obtained maximum preoperative information on the aneurysm's morphology and its relationship to parent and adjacent vessels by viewing the aneurysm in multiple projections. Routine posteroanterior, Towne's, and lateral views are studied before obtaining the special views required to visualize the junction of the aneurysm's base with the parent basilar artery. A base view has been particularly informative. Often several projections with different degrees of obliquity are required for precise definition of the lesion. Because of the deep and often prolonged retraction required to expose aneurysms in this location, like Drake we are reluctant to undertake surgery within the first postbleed week and in the presence of arterial spasm. 8 Except in cases with aneurysms presenting because of mass effects, we have not recommended operation for patients in a condition lower than Grade II. Drake proved that basilar aneurysms could and should be treated. Encouraged by his results others have followed Drake's lead with experience similar to our own. In our view, the earlier argument for nonsurgical management of basilar tip aneurysms no longer applies to patients who remain in or achieve a Grade II clinical status. We express our deep appreciation to neurosurgical colleagues who believe, as we do, that uncommon conditions must be collected and described in order to improve results through repetition and to them we are indebted for the patients in this series.
J. Neurosurg. / Volume 44 / May, I976
References I. DeSaussure RL Jr, Hunter E, Robertson JT: Saccular aneurysms of the posterior fossa. J Neurosurg 15:385-391, 1958 2. Dimsdale H, Logue V: Ruptured posterior fossa aneurysms and their surgical treatment. J Neuroi Neurosurg Psychiatry 22:202-217, 1959 3. Drake CG: Further experience with surgical treatment of aneurysms of the basilar artery. J Neurosurg 29:372-392, 1968 4. Drake CG: The surgical treatment of aneurysms of the basilar artery. J Neurosurg 29:436-446, 1968 5. Drake CG: Surgical treatment of ruptured aneurysms of the basilar artery. Experience with 14 cases. J Neurosurg 23:457-473, 1965 6. Drake CG: The surgical treatment of vertebral-basilar aneurysms. Clin Neurosurg 16:114-169, 1969 7. Hammon WM: Intracranial aneurysm encasement. J Neurol Neurosurg Psychiatry 31: 524-527, 1968 8. Hayes G J, Leaver RC: Methyl methacrylate investment of intracranial aneurysms. A report of seven years' experience. J Neurosurg 25:79-80, 1966 9. Hunt WE, Hess RM: Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg 28:14-20, 1968 10. Jamieson KG: Aneurysms of the vertebrobasilar system. Further experience with nine cases. J Neurosurg 28:544-555, 1967 11. Jamieson KG: Aneurysms of the vertebrobasilar system. Surgical intervention in 19 cases. J Neurosurg 21:781-797, 1964 12. Schwartz HG: Arterial aneurysm of the posterior fossa. J Neurosurg 5:312-316, 1948
This work was supported by NINS Training Grant 5593. Address reprint requests to: Charles B. Wilson, M.D., Department of Neurological Surgery, University of California School of Medicine. San Francisco, California 94143.
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