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Surgery of incidental intracranial aneurysms
432
Surg Neurol 1987;28:432-6
Surgery of Incidental
Intracranial
Aneurysms
0. Heiskanen, M.D., and A. Poranen, M.D. Neurosurgical
Department,
Helsinki
University
Central
Hospital,
Heiskanen 0, Poranen A. Surgery of incidental intracranial aneurysms. Surg Neural 1987;28:432-6.
A series of nine patients with an unruptured asymptomatic aneurysm not associated with a ruptured aneurysm is discussed. Three had giant aneurysms. Two patients had bilateral aneurysms of the middle cerebral artery. Five had solitary aneurysms of the middle cerebral artery. One had an aneurysm of the anterior communicating artery. One had an ophthalmic aneurysm. All aneurysms were clipped. Two operations were necessary in the two patients with bilateral aneurysms. There was no mortality and no significant morbidity. Clipping of the aneurysm is recommended for those patients who have no other serious illness that significantly increases the surgical risk. If a combination of pituitary tumor and aneurysm is found, a subfrontal instead of transsphenoidal approach should be considered so as to treat both the tumor and aneurysm at the same operation. KEY WORDS:
Incidental
aneurysm
Helsinki,
Finland
series is the one collected from 12 neurosurgical centers by Wirth et al [9]. Even in that series about 4 of 10 patients had SAH and multiple aneurysms. Our series is small but gives some idea about the problems and results of surgery for incidental intracranial aneurysms.
Materials and Methods Our series consists of nine patients with 11 unruptured asymptomatic aneurysms (Table 1). In four patients a carotid angiography was performed because of a pituitary tumor. In four patients the aneurysm was first found by CT scanning performed because of an epileptic seizure and in one patient because of tinnitus and diminished hearing in one ear. Five patients had an aneurysm of the middle cerebral artery. Two patients had a bilateral middle cerebral artery aneurysm. One patient had an aneurysm in the anterior communicating artery and one an ophthalmic aneurysm. The size of the aneurysm varied from 3 to 30 mm. The aneurysms diagnosed with CT scanning were all large, three of them giant ones. We had thorough discussions with all the patients about the risks of bleeding and of surgery. We assumed that the risk of rupture would be the same as that of unruptured aneurysm in patients with multiple aneurysms, i.e., 1.1% per year for bleeding [2). We made it absolutely clear that the aneurysm would be clipped only to prevent a rupture and bleeding and that it would have no effect on the patient’s presenting symptoms. None of the patients had any other illness which would have increased the risk of surgery. In two patients with bilateral middle cerebral aneurysms, two separate operations were performed at 2-month intervals. All patients had a postoperative angiography of the carotid arteries confirming the obliteration of the aneurysm. The followup time was from 4 months to 4 years (Figure I).
Incidental aneurysms are defined as unruptured, asymptomatic, and unrelated to the patient’s current symptoms [5]. Thus unruptured aneurysms of patients with subarachnoid hemorrhage (SAH) and multiple aneurysms are excluded, as are aneurysms causing compression of optic pathways, cranial nerves, brain, or the brainstem together with their respective symptoms and signs. The natural history of incidental aneurysms especially the risk of bleeding is not well known. It has been suggested that it is the same as the risk of bleeding for unruptured aneurysms in patients with multiple aneurysms [2,3}. It has also been suggested that only aneurysms larger than 7 or 10 mm in diameter present the risk of rupture [6,7], but others contend that smaller aneurysms also rupture E&9]. If incidental aneurysms are to be operated on, there should be no mortality and very low morbidity. The number of reported cases of incidental aneurysms that have undergone surgery is not large. The largest
Results
Address reprint requem to: 0. Heiskanen, M.D., Neurosurgical Department, Helsinki University Central Hospital, Topeliuksenkatu 5, 00260 Helsinki 26, Finland. Received March 6, 1987; accepted June 11, 1987.
All patients recovered well from the operation. There was no significant morbidity and only one epileptic ht in a patient who did not have epilepsy before the operation. She is on antiepileptic medication and has not had any further seizures. Three of the four patients with
0 1987 by Elsevier Science Publishing Co., Inc.
0090.3019/87/53.50
Incidental
Table
Intracranial
Aneurysms
Surg Neural 1987;28:432-6
1. Summary of Nine Cases with Incidental AJymptomatic intracranial
&Se NO.
Age
Sex
Site of aneurysm
3 4
41 47 56 53
M M M F
MCA MCA MCA MCA bilateral
5
34
F
MCA bilateral
1 2
6 7 8
61 35 49 66
9 Abbwiatrons:
M M M F
MCA ACoA OphtA MCA
ACoA, anterior communicating
Size of aneurysm (mm)
633
Aneuqvms Cause for investigation
3. 12
One GM Two GM One GM Tinnitus,
4, 12
Several
26 30 26
4 4 4 17
Pituitary Pituitary Pituitary Pituitary
arrery; F, female; GM, grand mal; M, male; MCA,
seizure seizures seizure hypacusis
seizures
cerebra]
Outcome
Clipping Clipping Clipping Clipping, two operations Clipping, two
Excellent Excellent Excellent Excellent Excellent
operations Clipping Clipping Clipping Clipping
adenoma adenoma adenoma adenoma middle
Mode of surgery
artery;
OphrA,
ophthalmic
Excellent Excellent Excellent Excellenr artery.
1. Case 1. (A) Computed tomography scan showing a large partly thrombosedaneurysm of the middle cerebral artery. (B) Angiography of the right carotid artery showing the aneurysm. (C) Postoperatitleangiog:rapby of the carotid arteries, aneurysm clipped.
Figure
Surg Neural 1987;28:432-6
Heiskanen
and Poranen
Figure 2. Case 4. (A) Angiography of the left carotid artery. antevoposteriov Gew. showing a moderately large anetuyun at the bifurcation of the middle cerebral artery. (B) Postoperative angiography of the left carotid artery, aneurym clipped. (C) Angiogvapby of the right carotid artery, basal oblique z,iezc. showing a small aneurym at the bifurcation of the middle cerebral artery. (D) Portoperatke angiography of the carotid arteriu. aneurysm clipped.
before the surgery have been free of attacks since the operation (follow-up time ranging from 9 months to 3 years). One of the patients has had one more seizure since the operation (Figure 2). In the four patients with a pituitary tumor, a transsphenoidal operation would ordinarily have been performed. In these patients it was decided to use the subfrontal approach in order to treat both the pituitary tumor and the aneurysm at the same time. In three of the four patients the visual acuity and the visual fields improved markedly. In the fourth the visual acuity and
epilepsy
fields remained unchanged (Figure 3). In one of the patients with a giant middle cerebral aneurysm, part of the neck had to be left outside the clip in order to avoid endangering the main trunk of the middle cerebral artery.
Discussion There are only a few reports on the natural history of incidental intracranial aneurysms. Zack et al Cl01 observed 10 patients from 2 to 7 years. Only one of the
Incidental
Intracranial
Aneurysms
Surg Neural 1987;28:432-6
435
Fig ure 3. Caw 6. (A) Computed tomo~rapb.y Stan .rhowing a contraste&Jaminn intra.&lar mass. (B) An~~o~raphy of the ri,&t carotid arteries .rhouYnR a .maN anenmm at the bifuvc~athrt of the middle ccrebraf artery best r,isualized in the iatrraf tjiew. (C) Po.ltoperatztje an,qiograph> of the carotid arteries. amuvyJm clipped.
had the aneurysm clipped. None of the other had bleeding during the follow-up period. Wiebers et al [7] reported 130 patients with unruptured but partly symptomatic aneurysms with a long follow-up period. Fifteen patients had bleeding, i.e., Il. 5+%,,the same rate as reported for unruptured aneurysms in patients with multiple aneurysms [2]. In the series of Wiebers et al [7], only aneurysms larger than 10 mm in diameter bled, none under that size. Wirth et al {9] published data on a series of patients from 12 centers. Sixty-six of the patients had an incidental aneurysm as defined earlier. There was no surgical mortality, and the surgical morbidity was 6.5%. They considered clipping of unruptured incidentally discovered aneurysms justified. Wiebers et al [7] recommended operation only for patients with aneurysms larger
patients nine
than 10 mm in diameter. Winn et al [S] disagreed with their conclusion, and stated that smalIer aneurysm may also bleed. We have also seen several cases in which an aneurysm smaller than 10 mm has ruptured. Three of our patients had solitary aneurysms smaller than that and two of the bilateral aneurysms of the middle cerebral artery were also under 10 mm. For us the only limit in size of the aneurysm was technical; the aneurysm should be big enough to get a clip on. Three of the aneurysms of the middle cerebral artery were giant ones. All could, however, be clipped, two of them completely. In one, a small part of the neck had to be left outside of the clip so as not to endanger the circulation in the main trunk of the middle cerebral artery. The risk of bleeding from the remaining portion of an aneurysm such as that is, however, small El]. Aneurysms in patients with pituitary adenoma have been reported earlier [4] but only one of their 11 patients had his aneurysm clipped. We generally perform a bilateral angiography of the carotid arteries on patients with a large or inactive pituitary tumor. Usually a transsphenoidal approach is used. If an aneurysm is observed, a subfrontal approach should be considered in order to treat both the tumor and the aneurysm at the same operation. The risk of bleeding from an incidental asymptomatic aneurysm is slight. Consequently, the risks of surgery must be smaller if we are to suggest operation to these patients. There has been no surgical mortality in either
436
Heiskanen
Surg Neurol 1987;28:432-6
the series published by Wirth et al {9] or in our series. Wirth et al had a significant morbidity in 6.5% of the cases; we have not had any significant morbidity in our patients. It is clear that patients with any other serious illness that could increase the surgical risk should not be subjected to surgery. As van Crevel et al 151 state, the problem is not whether but which patients should be operated on. We believe that the operation can be done in low-risk patients without mortality and with very low morbidity.
References 1. Feuerbach
I, Lindquist C, Lindquist M, Steiner of postoperative aneurysm rests. J Neurosurg
and Poranen
3. Heiskanen Neurosurg
0. The risks of surgery 1986;65:451-3.
4. Jakubowsky of pituitary
J, Kendall B. Coincidental aneurysms with tumour origin. J Neural Neurosurg Psychiatry 1978;41:972-9.
5. Van Crevel H, Habbema J, Braakman management of incidental intracranial rology 1986;36:1335-9.
for unruptured
aneurysms.
R. Decision analysis saccular aneurysms.
J
of the Neu-
6. Wiebers DO, Whisnant JP, O’Fallon WM. The natural history of unruptured intracranial aneurysms. N Engl J Med 1981;304:696-8. 7. Wiebers DO, Whisnant significance of unruptured rosurg 1987;66:23-9.
JP, Sundt TM Jr, O’Fallon WM. The intracranial saccular aneurysms. J Neu-
8. Winn HR, Almaan WS, Berga SL, Jane JE, Richardson AE. The long-term outcome in patients with multiple aneurysms. J Neurosurg 1983;59:642-51. L. Natural history 1987;66:38-4.
2. Heiskanen 0. The risk of bleeding from unruptured aneurysm in cases with multiple aneurysms. J Neurosurg 1981;55:524-6.
9. Wirth FP, Laws ER, Piepgras D, Scott RM. Surgical treatment incidental intracranial aneurysms. Neurosurgery 1983;12:507-11. 10. Zack DJ, Russell DB, Miller DR. Fortuitously cranial aneurysms. Arch Neurol 1980;37:39-41.
discovered
of
intra-
Surg Neurol 1987;28:432-6
Surgery of Incidental
Intracranial
Aneurysms
0. Heiskanen, M.D., and A. Poranen, M.D. Neurosurgical
Department,
Helsinki
University
Central
Hospital,
Heiskanen 0, Poranen A. Surgery of incidental intracranial aneurysms. Surg Neural 1987;28:432-6.
A series of nine patients with an unruptured asymptomatic aneurysm not associated with a ruptured aneurysm is discussed. Three had giant aneurysms. Two patients had bilateral aneurysms of the middle cerebral artery. Five had solitary aneurysms of the middle cerebral artery. One had an aneurysm of the anterior communicating artery. One had an ophthalmic aneurysm. All aneurysms were clipped. Two operations were necessary in the two patients with bilateral aneurysms. There was no mortality and no significant morbidity. Clipping of the aneurysm is recommended for those patients who have no other serious illness that significantly increases the surgical risk. If a combination of pituitary tumor and aneurysm is found, a subfrontal instead of transsphenoidal approach should be considered so as to treat both the tumor and aneurysm at the same operation. KEY WORDS:
Incidental
aneurysm
Helsinki,
Finland
series is the one collected from 12 neurosurgical centers by Wirth et al [9]. Even in that series about 4 of 10 patients had SAH and multiple aneurysms. Our series is small but gives some idea about the problems and results of surgery for incidental intracranial aneurysms.
Materials and Methods Our series consists of nine patients with 11 unruptured asymptomatic aneurysms (Table 1). In four patients a carotid angiography was performed because of a pituitary tumor. In four patients the aneurysm was first found by CT scanning performed because of an epileptic seizure and in one patient because of tinnitus and diminished hearing in one ear. Five patients had an aneurysm of the middle cerebral artery. Two patients had a bilateral middle cerebral artery aneurysm. One patient had an aneurysm in the anterior communicating artery and one an ophthalmic aneurysm. The size of the aneurysm varied from 3 to 30 mm. The aneurysms diagnosed with CT scanning were all large, three of them giant ones. We had thorough discussions with all the patients about the risks of bleeding and of surgery. We assumed that the risk of rupture would be the same as that of unruptured aneurysm in patients with multiple aneurysms, i.e., 1.1% per year for bleeding [2). We made it absolutely clear that the aneurysm would be clipped only to prevent a rupture and bleeding and that it would have no effect on the patient’s presenting symptoms. None of the patients had any other illness which would have increased the risk of surgery. In two patients with bilateral middle cerebral aneurysms, two separate operations were performed at 2-month intervals. All patients had a postoperative angiography of the carotid arteries confirming the obliteration of the aneurysm. The followup time was from 4 months to 4 years (Figure I).
Incidental aneurysms are defined as unruptured, asymptomatic, and unrelated to the patient’s current symptoms [5]. Thus unruptured aneurysms of patients with subarachnoid hemorrhage (SAH) and multiple aneurysms are excluded, as are aneurysms causing compression of optic pathways, cranial nerves, brain, or the brainstem together with their respective symptoms and signs. The natural history of incidental aneurysms especially the risk of bleeding is not well known. It has been suggested that it is the same as the risk of bleeding for unruptured aneurysms in patients with multiple aneurysms [2,3}. It has also been suggested that only aneurysms larger than 7 or 10 mm in diameter present the risk of rupture [6,7], but others contend that smaller aneurysms also rupture E&9]. If incidental aneurysms are to be operated on, there should be no mortality and very low morbidity. The number of reported cases of incidental aneurysms that have undergone surgery is not large. The largest
Results
Address reprint requem to: 0. Heiskanen, M.D., Neurosurgical Department, Helsinki University Central Hospital, Topeliuksenkatu 5, 00260 Helsinki 26, Finland. Received March 6, 1987; accepted June 11, 1987.
All patients recovered well from the operation. There was no significant morbidity and only one epileptic ht in a patient who did not have epilepsy before the operation. She is on antiepileptic medication and has not had any further seizures. Three of the four patients with
0 1987 by Elsevier Science Publishing Co., Inc.
0090.3019/87/53.50
Incidental
Table
Intracranial
Aneurysms
Surg Neural 1987;28:432-6
1. Summary of Nine Cases with Incidental AJymptomatic intracranial
&Se NO.
Age
Sex
Site of aneurysm
3 4
41 47 56 53
M M M F
MCA MCA MCA MCA bilateral
5
34
F
MCA bilateral
1 2
6 7 8
61 35 49 66
9 Abbwiatrons:
M M M F
MCA ACoA OphtA MCA
ACoA, anterior communicating
Size of aneurysm (mm)
633
Aneuqvms Cause for investigation
3. 12
One GM Two GM One GM Tinnitus,
4, 12
Several
26 30 26
4 4 4 17
Pituitary Pituitary Pituitary Pituitary
arrery; F, female; GM, grand mal; M, male; MCA,
seizure seizures seizure hypacusis
seizures
cerebra]
Outcome
Clipping Clipping Clipping Clipping, two operations Clipping, two
Excellent Excellent Excellent Excellent Excellent
operations Clipping Clipping Clipping Clipping
adenoma adenoma adenoma adenoma middle
Mode of surgery
artery;
OphrA,
ophthalmic
Excellent Excellent Excellent Excellenr artery.
1. Case 1. (A) Computed tomography scan showing a large partly thrombosedaneurysm of the middle cerebral artery. (B) Angiography of the right carotid artery showing the aneurysm. (C) Postoperatitleangiog:rapby of the carotid arteries, aneurysm clipped.
Figure
Surg Neural 1987;28:432-6
Heiskanen
and Poranen
Figure 2. Case 4. (A) Angiography of the left carotid artery. antevoposteriov Gew. showing a moderately large anetuyun at the bifurcation of the middle cerebral artery. (B) Postoperative angiography of the left carotid artery, aneurym clipped. (C) Angiogvapby of the right carotid artery, basal oblique z,iezc. showing a small aneurym at the bifurcation of the middle cerebral artery. (D) Portoperatke angiography of the carotid arteriu. aneurysm clipped.
before the surgery have been free of attacks since the operation (follow-up time ranging from 9 months to 3 years). One of the patients has had one more seizure since the operation (Figure 2). In the four patients with a pituitary tumor, a transsphenoidal operation would ordinarily have been performed. In these patients it was decided to use the subfrontal approach in order to treat both the pituitary tumor and the aneurysm at the same time. In three of the four patients the visual acuity and the visual fields improved markedly. In the fourth the visual acuity and
epilepsy
fields remained unchanged (Figure 3). In one of the patients with a giant middle cerebral aneurysm, part of the neck had to be left outside the clip in order to avoid endangering the main trunk of the middle cerebral artery.
Discussion There are only a few reports on the natural history of incidental intracranial aneurysms. Zack et al Cl01 observed 10 patients from 2 to 7 years. Only one of the
Incidental
Intracranial
Aneurysms
Surg Neural 1987;28:432-6
435
Fig ure 3. Caw 6. (A) Computed tomo~rapb.y Stan .rhowing a contraste&Jaminn intra.&lar mass. (B) An~~o~raphy of the ri,&t carotid arteries .rhouYnR a .maN anenmm at the bifuvc~athrt of the middle ccrebraf artery best r,isualized in the iatrraf tjiew. (C) Po.ltoperatztje an,qiograph> of the carotid arteries. amuvyJm clipped.
had the aneurysm clipped. None of the other had bleeding during the follow-up period. Wiebers et al [7] reported 130 patients with unruptured but partly symptomatic aneurysms with a long follow-up period. Fifteen patients had bleeding, i.e., Il. 5+%,,the same rate as reported for unruptured aneurysms in patients with multiple aneurysms [2]. In the series of Wiebers et al [7], only aneurysms larger than 10 mm in diameter bled, none under that size. Wirth et al {9] published data on a series of patients from 12 centers. Sixty-six of the patients had an incidental aneurysm as defined earlier. There was no surgical mortality, and the surgical morbidity was 6.5%. They considered clipping of unruptured incidentally discovered aneurysms justified. Wiebers et al [7] recommended operation only for patients with aneurysms larger
patients nine
than 10 mm in diameter. Winn et al [S] disagreed with their conclusion, and stated that smalIer aneurysm may also bleed. We have also seen several cases in which an aneurysm smaller than 10 mm has ruptured. Three of our patients had solitary aneurysms smaller than that and two of the bilateral aneurysms of the middle cerebral artery were also under 10 mm. For us the only limit in size of the aneurysm was technical; the aneurysm should be big enough to get a clip on. Three of the aneurysms of the middle cerebral artery were giant ones. All could, however, be clipped, two of them completely. In one, a small part of the neck had to be left outside of the clip so as not to endanger the circulation in the main trunk of the middle cerebral artery. The risk of bleeding from the remaining portion of an aneurysm such as that is, however, small El]. Aneurysms in patients with pituitary adenoma have been reported earlier [4] but only one of their 11 patients had his aneurysm clipped. We generally perform a bilateral angiography of the carotid arteries on patients with a large or inactive pituitary tumor. Usually a transsphenoidal approach is used. If an aneurysm is observed, a subfrontal approach should be considered in order to treat both the tumor and the aneurysm at the same operation. The risk of bleeding from an incidental asymptomatic aneurysm is slight. Consequently, the risks of surgery must be smaller if we are to suggest operation to these patients. There has been no surgical mortality in either
436
Heiskanen
Surg Neurol 1987;28:432-6
the series published by Wirth et al {9] or in our series. Wirth et al had a significant morbidity in 6.5% of the cases; we have not had any significant morbidity in our patients. It is clear that patients with any other serious illness that could increase the surgical risk should not be subjected to surgery. As van Crevel et al 151 state, the problem is not whether but which patients should be operated on. We believe that the operation can be done in low-risk patients without mortality and with very low morbidity.
References 1. Feuerbach
I, Lindquist C, Lindquist M, Steiner of postoperative aneurysm rests. J Neurosurg
and Poranen
3. Heiskanen Neurosurg
0. The risks of surgery 1986;65:451-3.
4. Jakubowsky of pituitary
J, Kendall B. Coincidental aneurysms with tumour origin. J Neural Neurosurg Psychiatry 1978;41:972-9.
5. Van Crevel H, Habbema J, Braakman management of incidental intracranial rology 1986;36:1335-9.
for unruptured
aneurysms.
R. Decision analysis saccular aneurysms.
J
of the Neu-
6. Wiebers DO, Whisnant JP, O’Fallon WM. The natural history of unruptured intracranial aneurysms. N Engl J Med 1981;304:696-8. 7. Wiebers DO, Whisnant significance of unruptured rosurg 1987;66:23-9.
JP, Sundt TM Jr, O’Fallon WM. The intracranial saccular aneurysms. J Neu-
8. Winn HR, Almaan WS, Berga SL, Jane JE, Richardson AE. The long-term outcome in patients with multiple aneurysms. J Neurosurg 1983;59:642-51. L. Natural history 1987;66:38-4.
2. Heiskanen 0. The risk of bleeding from unruptured aneurysm in cases with multiple aneurysms. J Neurosurg 1981;55:524-6.
9. Wirth FP, Laws ER, Piepgras D, Scott RM. Surgical treatment incidental intracranial aneurysms. Neurosurgery 1983;12:507-11. 10. Zack DJ, Russell DB, Miller DR. Fortuitously cranial aneurysms. Arch Neurol 1980;37:39-41.
discovered
of
intra-