Arthur I. Kobrine, MD, PhD
Intracranial Aneurysms: Interventional Neurovascular Treatment with Detachable Balloons' T
HE neurosurgical treatment of in tracranial aneurysms began in ear
nest in the 1940s when a number of pioneer neurosurgeons developed nec essary skills and technology to attack such lesions. Early clips were often
made of gold leaf and were formed at the operating table. The early clips were not spring-loaded but were squeezed down on the neck of the an eurysm by the surgeon. In many in stances this became a one-shot exercise, since once the clip was applied
it was
very difficult to remove. A huge jump forward
in the surgical
treatment
of in
tracranial aneurysms came with the spring-loaded
clip. This clip could be
removed and reapplied when neces sary. At the present time, there are lit erally hundreds of different configura tions of clips and dozens of different clip appliers. Usually the surgeon has a
general idea of the type of clip to use when the operation begins, but does not pick the definitive
clip until the an
eurysm has been dissected and ex posed. As cerebral angiography has im proved,
the ability to visualize
the an
eurysm prior to surgery has helped the surgeon plan the approach and has added information on the likely techni
cal difficulty of approaching aneurysm.
A further
was the introduction microscope
a specific
giant leap forward
of the operating
in neurosurgery
in the ear
ly 1970s. With the operating micro scope, the ability to dissect the aneu rysm and preserve small perforators al lowed the results to significantly improve. Along with improvements in
Index terms: Aneurysm, intracranial, 10.73 Aneurysm, therapy, 10.1299 •¿ Catheters and catheterization •¿ Editorials
Radiology 1991;178:627-628
‘¿From2440 M St NW, Ste 315, Washington, DC 20037. Received December 10, 1990; accept ed December 12. Address reprint requests to the author. c RSNA, 1991 See also the article by Higashida et al (pp 663—670)and the editorial by Chase (pp 624626) in this issue.
anesthesia technique and anesthesia agents, it became commonplace for the surgeon to clip larger and more diffi cult aneurysms. Introduction of extra cranial-intracranial bypass surgery, with use of microsurgical techniques, allowed the surgeon to trap a giant an
eurysm without a neck and preserve flow to an area of the brain that might otherwise be compromised. The occurrence of vasospasm has a!ways been a complicating factor in the treatment of aneurysms. Various drug protocols have been tried, some with limited success, but the problem still remains. The calcium ion channel blockers appear to be the best hope at the present time. The timing of surgery to obliterate aneurysms continues to be
a bit of a controversy. Of course, for un ruptured aneurysms, timing is not a problem. However, in the patient who has had a subarachnoid hemorrhage, early versus late surgery continues to be a major topic of discussion at nation al neurosurgical meetings. It appears that the overall treatment mortality and morbidity are not too different in the two groups. The late group appears to benefit more from the surgical as sault itself; however, during the wait ing period patients may experience ei ther rebleeding or vasospasm that can not be aggressively treated. Early surgery in a patient with an acute sub arachnoid hemorrhage is often more difficult technically because of a swol len “¿angry brain.― However, once the aneurysm is clipped, any subsequent vasospasm could be treated aggressive ly with hypertensive therapy and, ob viously, rebleeding is no longer a prob lem. In spite of the large advances made in the surgical treatment of aneurysms, there continue to be major problems. Certain aneurysms, most notably those arising from the cavernous portion of the carotid artery or supraclinoid aneu rysms whose neck is not approachable through a subarachnoid route, are real ly not candidates for surgical therapy. These aneurysms are best treated by in terventional neuroradiologic means. The techniques and results outlined in the article by Higashida et al in this is sue of Radiology are promising and en couraging (1). Although several attempts have been
made by various surgeons to directly attack carotid cavernous fistulas, as well as large carotid artery aneurysms within the cavernous sinus, the mortal ity and
morbidity
of such
assaults
re
mains high and these lesions appear to be better attacked with the balloon catheter. The flexibility of placing the balloon directly in the aneurysm, prox imal obliteration, and proximal plus distal obliteration all make the balloon catheter approach ideal for such aneu rysms. However, intracranial aneu rysms both large and small, where the neck is approachable within the sub arachnoid space, are a different matter. It seems to me that there are a number of advantages for direct surgical attack on intracranial
subarachnoid
aneu
rysms. During an open surgical ap proach, the blood clot surrounding the aneurysm, and often the blood clot within the subarachnoid space, can be removed by the surgeon. In my opin ion, this decreases the likelihood of spasm occurring later in the postopera tive course. The neck can be delineated with use of microtechniques, and it is rare that the neck of an aneurysm can not be clipped, if the neck is indeed within the subarachnoid space. The surgeon can apply topical agents such as phentolamine hydrochloride (Regi tine; Ciba-Geigy, Summit, NJ) to the vessels, which in my opinion will help decrease the likelihood of vaso spasm. Perhaps the greatest advantage of a direct surgical attack on the aneurysm is dealing with the catastrophic compli cation of rupture. If the surgeon is fac ing the aneurysm and the head is open, acute rupture of the aneurysm while the clip is being applied can be dealt with. If the aneurysm ruptures in the radiology suite while the interven tional radiologist is inflating the bal loon, there is little that can be done for the patient. I am aware of at least one such occurrence in the last year. A pa tient who had a basilar tip aneurysm that was considered technically too dif ficult to approach surgically was treat ed with interventional ballooning. The aneurysm ruptured as the balloon was inflated, and the patient died almost immediately. Higashida et al do not ad dress this possible complication, which I think represents a very real difference 627
between the potential advantages of the two techniques. Higashida et al do not discuss vaso spasm, either before or after treatment. This is quite a sensitive subject for neu rosurgeons. Many patients who have had aneurysms clipped successfully de velop vasospasm that begins as late as 14 days after surgery. The timing of the interventional procedure is not dis cussed at length in the article, and again, this is a question that is all-im portant to the neurosurgeon. Of course, for unruptured aneurysms timing is not an issue. However, in the case of a patient with an acute subarachnoid hemorrhage, the reader cannot get a sense from this article at what stage the authors consider it ideal to perform balloon catheterization. They do men tion at one point that they like to wait 6 weeks before attempting to balloon the aneurysm in nonacute patients. They state that a fresh thrombus within the
628 •¿ Radiology
aneurysm might break free if the bal boning is carried out at an earlier date. No mention is made of the rebleeding rate in patients waiting for the proce dure or of the difference in the preva lence of spasm when the patient is bal looned early or late. These are impor tant considerations that should be addressed more fully in the future. In spite of what I, as a neurosurgeon, consider shortcomings in the study, I feel nevertheless that the report by Hi gashida et al is an important article. The neurosurgical treatment of aneu rysms is significantly less than ideal, so other methods of treatment are clearly welcomed. At this time, however, I find little advantage to balloon cathe terization of aneurysms whose necks,
even when wide, are clearly within the subarachnoid space and within reach of
candidates for interventional balloon catheterization. Perhaps, in the future, a merging of the two techniques will afford better results than either technique alone. I can easily envision a situation in which a neurosurgeon operates on a patient with an aneurysm and exposes the an eurysm, and then a joint venture of clipping and ballooning ends up being the ideal way to obliterate the aneu rysm while preserving flow through parent and adjacent vessels. U
Reference 1. Higashida RT, Halbach VV, Dowd CF, Barnwell SU, Hieshima GB. Intracranial aneurysms: interventional neurovascular treatmentwithdetachable balloons—re sultsin215cases. Radiology1991;178:663— 670.
the neurosurgeon's tools. Aneurysms whether small or large—whose necks are in the cavernous sinus or far enough under the anterior clinoid that they are not approachable are the ideal
March 1991
Intracranial Aneurysms: Interventional Neurovascular Treatment with Detachable Balloons' T
HE neurosurgical treatment of in tracranial aneurysms began in ear
nest in the 1940s when a number of pioneer neurosurgeons developed nec essary skills and technology to attack such lesions. Early clips were often
made of gold leaf and were formed at the operating table. The early clips were not spring-loaded but were squeezed down on the neck of the an eurysm by the surgeon. In many in stances this became a one-shot exercise, since once the clip was applied
it was
very difficult to remove. A huge jump forward
in the surgical
treatment
of in
tracranial aneurysms came with the spring-loaded
clip. This clip could be
removed and reapplied when neces sary. At the present time, there are lit erally hundreds of different configura tions of clips and dozens of different clip appliers. Usually the surgeon has a
general idea of the type of clip to use when the operation begins, but does not pick the definitive
clip until the an
eurysm has been dissected and ex posed. As cerebral angiography has im proved,
the ability to visualize
the an
eurysm prior to surgery has helped the surgeon plan the approach and has added information on the likely techni
cal difficulty of approaching aneurysm.
A further
was the introduction microscope
a specific
giant leap forward
of the operating
in neurosurgery
in the ear
ly 1970s. With the operating micro scope, the ability to dissect the aneu rysm and preserve small perforators al lowed the results to significantly improve. Along with improvements in
Index terms: Aneurysm, intracranial, 10.73 Aneurysm, therapy, 10.1299 •¿ Catheters and catheterization •¿ Editorials
Radiology 1991;178:627-628
‘¿From2440 M St NW, Ste 315, Washington, DC 20037. Received December 10, 1990; accept ed December 12. Address reprint requests to the author. c RSNA, 1991 See also the article by Higashida et al (pp 663—670)and the editorial by Chase (pp 624626) in this issue.
anesthesia technique and anesthesia agents, it became commonplace for the surgeon to clip larger and more diffi cult aneurysms. Introduction of extra cranial-intracranial bypass surgery, with use of microsurgical techniques, allowed the surgeon to trap a giant an
eurysm without a neck and preserve flow to an area of the brain that might otherwise be compromised. The occurrence of vasospasm has a!ways been a complicating factor in the treatment of aneurysms. Various drug protocols have been tried, some with limited success, but the problem still remains. The calcium ion channel blockers appear to be the best hope at the present time. The timing of surgery to obliterate aneurysms continues to be
a bit of a controversy. Of course, for un ruptured aneurysms, timing is not a problem. However, in the patient who has had a subarachnoid hemorrhage, early versus late surgery continues to be a major topic of discussion at nation al neurosurgical meetings. It appears that the overall treatment mortality and morbidity are not too different in the two groups. The late group appears to benefit more from the surgical as sault itself; however, during the wait ing period patients may experience ei ther rebleeding or vasospasm that can not be aggressively treated. Early surgery in a patient with an acute sub arachnoid hemorrhage is often more difficult technically because of a swol len “¿angry brain.― However, once the aneurysm is clipped, any subsequent vasospasm could be treated aggressive ly with hypertensive therapy and, ob viously, rebleeding is no longer a prob lem. In spite of the large advances made in the surgical treatment of aneurysms, there continue to be major problems. Certain aneurysms, most notably those arising from the cavernous portion of the carotid artery or supraclinoid aneu rysms whose neck is not approachable through a subarachnoid route, are real ly not candidates for surgical therapy. These aneurysms are best treated by in terventional neuroradiologic means. The techniques and results outlined in the article by Higashida et al in this is sue of Radiology are promising and en couraging (1). Although several attempts have been
made by various surgeons to directly attack carotid cavernous fistulas, as well as large carotid artery aneurysms within the cavernous sinus, the mortal ity and
morbidity
of such
assaults
re
mains high and these lesions appear to be better attacked with the balloon catheter. The flexibility of placing the balloon directly in the aneurysm, prox imal obliteration, and proximal plus distal obliteration all make the balloon catheter approach ideal for such aneu rysms. However, intracranial aneu rysms both large and small, where the neck is approachable within the sub arachnoid space, are a different matter. It seems to me that there are a number of advantages for direct surgical attack on intracranial
subarachnoid
aneu
rysms. During an open surgical ap proach, the blood clot surrounding the aneurysm, and often the blood clot within the subarachnoid space, can be removed by the surgeon. In my opin ion, this decreases the likelihood of spasm occurring later in the postopera tive course. The neck can be delineated with use of microtechniques, and it is rare that the neck of an aneurysm can not be clipped, if the neck is indeed within the subarachnoid space. The surgeon can apply topical agents such as phentolamine hydrochloride (Regi tine; Ciba-Geigy, Summit, NJ) to the vessels, which in my opinion will help decrease the likelihood of vaso spasm. Perhaps the greatest advantage of a direct surgical attack on the aneurysm is dealing with the catastrophic compli cation of rupture. If the surgeon is fac ing the aneurysm and the head is open, acute rupture of the aneurysm while the clip is being applied can be dealt with. If the aneurysm ruptures in the radiology suite while the interven tional radiologist is inflating the bal loon, there is little that can be done for the patient. I am aware of at least one such occurrence in the last year. A pa tient who had a basilar tip aneurysm that was considered technically too dif ficult to approach surgically was treat ed with interventional ballooning. The aneurysm ruptured as the balloon was inflated, and the patient died almost immediately. Higashida et al do not ad dress this possible complication, which I think represents a very real difference 627
between the potential advantages of the two techniques. Higashida et al do not discuss vaso spasm, either before or after treatment. This is quite a sensitive subject for neu rosurgeons. Many patients who have had aneurysms clipped successfully de velop vasospasm that begins as late as 14 days after surgery. The timing of the interventional procedure is not dis cussed at length in the article, and again, this is a question that is all-im portant to the neurosurgeon. Of course, for unruptured aneurysms timing is not an issue. However, in the case of a patient with an acute subarachnoid hemorrhage, the reader cannot get a sense from this article at what stage the authors consider it ideal to perform balloon catheterization. They do men tion at one point that they like to wait 6 weeks before attempting to balloon the aneurysm in nonacute patients. They state that a fresh thrombus within the
628 •¿ Radiology
aneurysm might break free if the bal boning is carried out at an earlier date. No mention is made of the rebleeding rate in patients waiting for the proce dure or of the difference in the preva lence of spasm when the patient is bal looned early or late. These are impor tant considerations that should be addressed more fully in the future. In spite of what I, as a neurosurgeon, consider shortcomings in the study, I feel nevertheless that the report by Hi gashida et al is an important article. The neurosurgical treatment of aneu rysms is significantly less than ideal, so other methods of treatment are clearly welcomed. At this time, however, I find little advantage to balloon cathe terization of aneurysms whose necks,
even when wide, are clearly within the subarachnoid space and within reach of
candidates for interventional balloon catheterization. Perhaps, in the future, a merging of the two techniques will afford better results than either technique alone. I can easily envision a situation in which a neurosurgeon operates on a patient with an aneurysm and exposes the an eurysm, and then a joint venture of clipping and ballooning ends up being the ideal way to obliterate the aneu rysm while preserving flow through parent and adjacent vessels. U
Reference 1. Higashida RT, Halbach VV, Dowd CF, Barnwell SU, Hieshima GB. Intracranial aneurysms: interventional neurovascular treatmentwithdetachable balloons—re sultsin215cases. Radiology1991;178:663— 670.
the neurosurgeon's tools. Aneurysms whether small or large—whose necks are in the cavernous sinus or far enough under the anterior clinoid that they are not approachable are the ideal
March 1991
