- Email: [email protected]
Coil embolization of ruptured vertebral dissection in acute stage with interlocking detachable coils
ELSEVIER
COIL EMBOLIZATION OF RUPTURED VERTEBRAL DISSECTION IN ACUTE STAGE WITH INTERLOCKING DETACHABLE COILS Hiroshi Manabe, M.D., Hiroki Ohkuma, M.D., Seiichiro Fujita, M.D., and Shigeharu Suzuki, M.D. Department of Neurosurgery, Hirosaki University School of Medicine, Hirosaki, Japan
Manabe H, Ohkuma H, Fujita S, Suzuki S. Coil embolization of ruptured vertebral dissection in acute stage with interlocking detachable coils. Surg Neurol 1997;47:476-80.
been reported so far. Many kinds of surgical treatments such as proximal clipping, trapping, wrap-
BACKGROUND
have been reported for ruptured aneurysms of this sort [3,4,6,8,21,22,24]. However, the best surgical method still remains controversial. In a recent paper, an endovascular proximal occlusion of the vertebral artery or of a dissected portion was performed with Guglielmi’s detachable coils (GDC) [8], which can be detached from the pusher wire with electrocurrents [ 71. The interlocking detachable coil (IDC) (Target Therapeutics, Fremont, CA), on the other hand, is a newly developed detachable coil for vascular lesions that can be detached from the pusher wire by mechanical force [131. In this report, a case of ruptured vertebral dissecting aneurysm arising between the posterior inferior cerebellar artery (PICA) and the vertebrobasilar union was treated successfully with IDCs during the acute stage. The usefulness of IDCs in the treatment of this kind of lesion is also discussed.
Although dissecting aneurysm of vertebral artery is known as one of the causesof subarachnoid hemorrhage (SAH) in the posterior circulation, the best surgical treatment method remains controversial. METHOD
AND
RESULT
This 64-year-old woman was admitted to our service with headache due to SAH caused by a ruptured vertebra1 dissecting aneurysm in the distal portion of the posterior inferior cerebellar artery. After confirming tolerance of parent artery occlusion by temporary balloon occlusion, both the dissection site and the proximal portion of the parent artery were occluded completely by interlocking detachable coils (IDCs) without any ischemic complications. The patient was discharged without any neurologic deficit on the 25th day after the therapy. CONCLUSION
The goal of treatment for the ruptured dissecting aneurysm is isolation of the dissection site from the circulation to prevent rerupture. In our case, endovascular occlusion with IDCswas sufficient to reach the goal. In cases with difficulties in the surgical approach, embolization of the dissection site with IDCs should be considered. 0 1997by Elsevier Science Inc. KEY
WORDS
Ruptured vertebral embolization.
dissecting aneurysm, IDC, coil
D
issecting aneurysms of the vertebral artery are recognized as a common cause of stroke in the posterior circulation. Many cases of subarachnoid hemorrhage (SAH) due to rupture of a vertebra1 dissecting aneurysm in particular have Address reprint requests to: Hiroshi rosurgery, Hirosaki University School Aomori 036, Japan. Received January 30, 1996; accepted 00903019/97/$17.00 PI1 s009(r3019(96)00390-4
Manabe, M.D., Department of Medicine, 5 Zaifu cho, June
10, 1996.
of NeuHirosaki,
ping, or endovascular
proximal balloon occlusion
CASE REPORT This 64year-old woman, having suffered from occipitalgia for 5 days, was transferred to our service. She showed only neck stiffness neurologically and was diagnosed by CT scan as having SAH. Cerebral angiograms revealed an unusual aneurysmal dilatation of the right vertebral artery at a site distal to the PICA, and a retention of contrast medium in the
aneurysm in the venous phase (Figure 1 A, B, C). Anteroposterior view of the right vertebral angiogram also showed the arterial dilatation exactly in the middle portion of the medulla oblongata (Figure 1 B). The patient was diagnosed as having WI-I due 655 Avenue
0 1997 by Elsevier Science Inc. of the Americas, New York, NY 10010
Coil Embolization
of Ruptured Dissecting Aneurysm
Surg Neurol 1997;47:476-80
Right vertebral angiorams revealed the unusual aneurysmal dilatation of the right vertebral 0that thePICA in the venous phase (c>. Left vertebral (A, B), and retention of contrast medium left vertebral artery was almost equal to the right vertebral artery in caliber (D). (arrow)
to rupture of a dissecting vertebral aneurysm. The right vertebral artery was almost equal to the left one in caliber (Figure 1 D), and there were no perforating branches on the right vertebral artery between the aneurysm and the PICA (Figure 1 B). Temporary balloon occlusion of right vertebral artery at the V2 portion for 20 minutes with systemic heparinization caused no ischemic signs at all. Seven hundred and forty MBq of 99m Tchexamethylene propylene amine oxime (99m TcHMPAO) was injected intravenously 5 minutes after the balloon inflation. The single photon emission computed tomography (SPECT) study performed immediately after the balloon deflation showed no decreased perfusion area in the cerebellum, brain stem, or bilateral posterior lobe. A 6-F guiding catheter (Toray, Tokyo) was inserted into the right vertebral artery via the right femoral artery, and a Tracker 18 catheter (Target Therapeutics) was introduced into the dissection coaxially with systemic heparinization (5000 U). Five IDCs (5 mm-15 cm, 1; 3 mm-6 cm, 2; 3 mm-3 cm, 2) were inserted and released. The aneurysm and its proximal vertebral artery between the aneurysm and the right
477
artery distal to the angiogram showed
PICA were occluded (Figure 2). After the procedure, heparinization was reversed by intravenous administration of protamine sulfate, and antiplatelets were administered. The patient’s postoperative course was uneventful and she was discharged
Right vertebral angiogram showed complete occluqwith IDCs sion of the right vertebral artery distal to the PICA that were packed in the dissection site and the proximal portion of the vertebral artery.
478
Surg Neurol 1997;47:476-80
Follow-up right vertebral angiogram taken 3 months after the embolization, showed no change from that taken just after the embolization procedure, except that the PICA became rather dilated.
without any neurologic deficit on the 25th day after the occlusion. Follow-up angiograms taken 3 months after the embolization revealed complete occlusion of the right vertebral artery distal to the PICA (Figure 3).
DISCUSSION Although dissecting aneurysms of the vertebral artery have been noted to cause SAH, the exact incidence of rupture of vertebral artery dissections is still unclear. There are reports that 28% of 94 vertebral aneurysms were the dissecting type with 81% incidence of rupture [24], and that 45% of 110 autopsied patients with SAH were cases with rupture of a vertebral artery dissection [ 181. These reports suggest the incidence of ruptured vertebral artery dissection might be higher than we assumed. The rebleeding rate of ruptured vertebral artery dissections is said to be 24% [24], 30% [2], or 71.4% [14], and to occur mostly during the acute stage [2,14, 251. Therefore, surgical or endovascular treatment in the acute stage may be important for prevention of rerupture [ 2,8,14]. As vertebral artery dissections are usually fusiform, treatment options are proximal clipping, proximal endovascular occlusion, wrapping, or trapping [3,4,6,8,21,22,24]. Wrapping is recommended only for cases that fail of occlusion test of the affected vertebral artery [24,25], and proximal clipping is most widely accepted for cases that pass the test [24,25]. The goal of treatment of the ruptured dissecting aneurysms is isolation of the dissection site from the circulation to prevent rerupture [lo]. Although proximal clipping has met with
Manabe et al
a good clinical result in many cases, it might not be sufficient to achieve the goal. Three cases with rerupture of ruptured vertebral dissecting aneurysms located at the distal portion of the PICA, occurred after treatment by proximal clipping either distal or proximal to the PICA, were reported [2,6,10]. And another suggestive case was also reported, in which sudden swelling of a vertebral dissecting aneurysm distal to the PICA had occurred during surgery just after the vertebral artery had been clipped between the PICA and the aneurysm [9]. Those four cases were finally treated by trapping, and gave us a suggestion that contralateral retrograde flow may cause a rerupture after proximal clipping of the affected vertebral artery either proximal or distal to the PICA [lo]. Sasaki et al. divided vertebral dissections into two groups based on the clinical and pathologic features: (1) an aneurysm of which the dissection is confined to the vertebral artery, and (2) an aneurysm of which the dissection extended to the basilar artery [ 181. In the former group, the major clinical feature is SAH due to rupture of all three layers of the arterial wall. Such a dissection occurs usually in the subadventitial layer. In the latter, on the other hand, the major pathognomonic factor is a brain stem infarction due to luminal occlusion by intramural hematoma. They assumed that the dissection occurs initially between the intima and media, which is followed sometimes by destruction of all layers of arterial wall and induces SAH. The dissection confined within the arterial wall may cause a luminal occlusion. These pathologic fmdings of ruptured dissecting aneurysms suggest that proximal occlusion might leave the possibility of rebleeding in cases with rich contralateral retrograde filling. Angiographic findings of vertebrobasilar dissecting aneurysms are characteristic, and are divided generally into three categories: (1) those showing changes of the original arterial lumen by intramural hematoma, such as a rosette-shaped opaque area [15,19], “string sign” [17], and fusiform aneurysm with proximally and distally narrowed sections [23]; (2) those showing pseudolumen, such as retention of contrast medium in the late angiographic phase [ 11, “pea-sized oblong bulge” [5], and double lumina as evidenced by different density of contrast material [ 111; (3) and those showing a dissected arterial wall by a flap of intimal layer [ 161. A decisive diagnostic angiographic finding is a double lumen, which is a radical pathologic condition of a dissecting aneurysm [ 20,251. Contrast medium retention in the venous phase seen in our case may indicate the dissected and ruptured region.
Coil Embolization
of Ruptured Dissecting Aneurysm
For cases that are tolerant of parent artery occlusion, trapping should first be considered. In our case, however, direct surgery may have been difficult because of its location and also, in a proximal occlusion either distal or proximal to the PICA, there would remain the risk of rebleeding because the dissection itself could not be occluded [22]. Eventually, the dissection site was occluded by endovascular therapy with IDCs. IDC is a safe endovascular occlusion material for aneurysms or blood vessels, and is detached from the pusher wire by mechanical force [7]. Two major characteristics of the IDC are: (1) its interventional advance and retraction are easy; and (2) its detachment is very quick [ 71. We could easily guide the IDCs to the dissection site with less mechanical stress on the aneurysm wall, and succeed in occluding a short segment including the dissection site and its proximal part of the vertebral artery without ischemic complications. As in our case, the occlusion of the vertebral artery must be kept as short as possible in order to avoid the occlusion of perforators to the brain stem, because there are O-3 (mean: 0.5) tiny perforating branches originating from the vertebral artery at the proximal segment to the PICA, and O-5 (mean: 1.8) perforators at the distal segment to the PICA [12]. Occlusion of any of those perforators causes
medullary
infarction
[3,24].
Perforating
branches originating from the vertebral artery at the distal segment of the occlusion will be supplied by retrograde filling. But anticoagulation therapy should be started immediately after the occlusive procedure to prevent unexpected progressive thrombosis in the distal segment [8], which may occlude the perforating branches and cause medullary infarction [ 251.
Surg Nemo1 1997;47:476-80
6. 7.
8.
9.
10. 11. 12. 13.
14.
15. 16.
17.
REFERENCES 1. Anderson RM, Schechter MM. A case of spontaneous dissecting aneurysm of the internal carotid artery. J Neurol Neurosurg Pyschiatry 1959;22:195201. 2. Aoki N, Sakai T. Rebleeding from intracranial dissecting aneurysm in the vertebral artery. Stroke 1990;21: 1628-31. 3. Aymard A, Gobin YP, Hodes JE, Bien S, Rufenacht D, Reizine D, George B, Merland JJ. Endovascular occlusion of vertebral arteries in the treatment of unclippable vertebrobasilar aneurysms. J Neurosurg 1991; 74:393-g. 4. Berger MS, Wilson CB. Intracranial dissecting aneurysms of the posterior circulation. J Neurosurg 1984; 61:882-94. 5. Bostrom K, Liliequist B. Primary dissecting aneurysm of the extracranial part of the internal carotid and
18.
19. 20. 21.
22.
479
vertebral arteries. A report of three cases. Neurology 1967;17:179-86. Friedman AH, Drake CC. Subarachnoid hemorrhage from intracranial dissecting aneurysm. J Neurosurg 1984;60:325-34. Guglielmi G, Vinuela F, Sepetka I, Macellari V. Electrothrombosis of saccular aneurysms via endovascular approach. Part 1: electrochemical basis, technique, and experimental results. J Neurosurg 1991; 75:1-7. Halbach W, Higashida RT, Dowd CF, Fraser KW, Smith TP, Teitelbaum GP, Wilson CB, Hieshima GB. Endovascular treatment of vertebral artery dissections and pseudoaneurysms. J Neurosurg 1993;79: 183-91. Irikura K, Miyasaka Y, Ohtaka H, Yada K, Hirose R. Dissecting aneurysm of the vertebral artery with lateral medullary syndrome. A case report, with special reference to surgical treatment. (in Japanese) Jpn J Stroke 1989;11:113-39. Kitanaka C, Morimoto T, Sasaki T, Takakura K. Rebleeding from vertebral artery dissection after proximal clipping. J Neurosurg 1992;77:466-8. Kunze S, Schiefer W. Angiographic demonstration of a dissecting aneurysm of the middle cerebral artery. Neuroradiology 1971;2:201-6. Lister JR, Rhoton AL, Matsushima T, Peace DA. Microsurgical anatomy of the posterior inferior cerebellar artery. Neurosurgery 1982; 10: 170-99. Marks MP, Chee H, Liddell RP, Steinberg GK, Panahian N, Lane B. A mechanically detachable coil for the treatment of aneurysms and occlusion of blood vessels. AJNR 1994;15:825-27. Mizutani T, Aruga T, Kirino T, Miki Y, Saito 1,Tsuchida T. Recurrent subarachnoid hemorrhage from untreated ruptured vertebrobasilar dissecting aneurysms. Neurosurgery 1995;36:905-13. Nelson JW. Dissecting subintimal hematomas of the intracranial arteries. Report of a case. J Am Osteopath Assoc 1968;67:512-27. New PFJ, Momose KJ. Traumatic dissection of the internal carotid artery at the atlatoaxial level, secondary to nonpenetrating injury. Radiology 1969;93:4149. Ojemann RG, Fisher CM, Rich JC. Spontaneous dissecting aneurysm of the internal carotid artery. Stroke 1972;3:434-40. Sasaki 0, Ogawa H, Koike T, Koizumi T, Tanaka R. A clinicopathological study of dissecting aneurysms of the intracranial vertebral artery. J Neurosurg 1991;75: 874-82. Scott GE, Neubuerger KT, Denst F. Dissecting aneurysms of intracranial arteries. Neurology 1960;10:2227. Shimoji T, Bando K, Nakajima K, Ito K. Dissecting aneurysm of the vertebral artery. J Neurosurg 1984; 61:1038-46. Takahashi A, Sugawara T, Suga T, Su CC, Kawakami K, Yoshimoto T. Detachable balloon treatment of dissecting vertebral aneurysm in its acute stage of sub arachnoid hemorrhage (in Japanese). Surgery Cerebral Stroke 1989;17:44-48. Tsukahara T, Wada H, Satake K, Yaoita H, Takahashi A. Proximal balloon occlusion for dissecting vertebral
480
Surg Neurol 1997;47:476-80
Manabe et al
aneurysms accompanied by subarachnoid hemorrhage. Neurosurgery 1995;36:914-20. 23. Waga S, Fujimoto K, Morooka Y. Dissecting aneurysm of the vertebral artery. Surg Neurol 1978;lO: 237-9. 24. Yamaura A. Diagnosis and treatment of vertebral aneurvsms. J Neurosure 1988:69:345-g. 25. Yamaura A, Watanabe Y, Saeki N. Dissecting aneurysms of the intracranial vertebral artery. J Neurosurg 1990;72:183-8.
66 Is
COMMENTARY I think this is an interesting case, appropriately treated with retrievable coils. The risks with a detached balloon would have been higher (e.g., dissection, rupture, occlusion of perforators).
URGICAL NEUROLOGY'S" [email protected]
66
S
Gerard Debrun,M.D. Chicago, Illinois
E-MAIL
ADDRESS:
URGICAL NEUROLOGY'S" HOME PAGE ON THE INTERNET: HTTP://WWW.ELSEVIER.NL/LOCATE/ SURNEU.
COIL EMBOLIZATION OF RUPTURED VERTEBRAL DISSECTION IN ACUTE STAGE WITH INTERLOCKING DETACHABLE COILS Hiroshi Manabe, M.D., Hiroki Ohkuma, M.D., Seiichiro Fujita, M.D., and Shigeharu Suzuki, M.D. Department of Neurosurgery, Hirosaki University School of Medicine, Hirosaki, Japan
Manabe H, Ohkuma H, Fujita S, Suzuki S. Coil embolization of ruptured vertebral dissection in acute stage with interlocking detachable coils. Surg Neurol 1997;47:476-80.
been reported so far. Many kinds of surgical treatments such as proximal clipping, trapping, wrap-
BACKGROUND
have been reported for ruptured aneurysms of this sort [3,4,6,8,21,22,24]. However, the best surgical method still remains controversial. In a recent paper, an endovascular proximal occlusion of the vertebral artery or of a dissected portion was performed with Guglielmi’s detachable coils (GDC) [8], which can be detached from the pusher wire with electrocurrents [ 71. The interlocking detachable coil (IDC) (Target Therapeutics, Fremont, CA), on the other hand, is a newly developed detachable coil for vascular lesions that can be detached from the pusher wire by mechanical force [131. In this report, a case of ruptured vertebral dissecting aneurysm arising between the posterior inferior cerebellar artery (PICA) and the vertebrobasilar union was treated successfully with IDCs during the acute stage. The usefulness of IDCs in the treatment of this kind of lesion is also discussed.
Although dissecting aneurysm of vertebral artery is known as one of the causesof subarachnoid hemorrhage (SAH) in the posterior circulation, the best surgical treatment method remains controversial. METHOD
AND
RESULT
This 64-year-old woman was admitted to our service with headache due to SAH caused by a ruptured vertebra1 dissecting aneurysm in the distal portion of the posterior inferior cerebellar artery. After confirming tolerance of parent artery occlusion by temporary balloon occlusion, both the dissection site and the proximal portion of the parent artery were occluded completely by interlocking detachable coils (IDCs) without any ischemic complications. The patient was discharged without any neurologic deficit on the 25th day after the therapy. CONCLUSION
The goal of treatment for the ruptured dissecting aneurysm is isolation of the dissection site from the circulation to prevent rerupture. In our case, endovascular occlusion with IDCswas sufficient to reach the goal. In cases with difficulties in the surgical approach, embolization of the dissection site with IDCs should be considered. 0 1997by Elsevier Science Inc. KEY
WORDS
Ruptured vertebral embolization.
dissecting aneurysm, IDC, coil
D
issecting aneurysms of the vertebral artery are recognized as a common cause of stroke in the posterior circulation. Many cases of subarachnoid hemorrhage (SAH) due to rupture of a vertebra1 dissecting aneurysm in particular have Address reprint requests to: Hiroshi rosurgery, Hirosaki University School Aomori 036, Japan. Received January 30, 1996; accepted 00903019/97/$17.00 PI1 s009(r3019(96)00390-4
Manabe, M.D., Department of Medicine, 5 Zaifu cho, June
10, 1996.
of NeuHirosaki,
ping, or endovascular
proximal balloon occlusion
CASE REPORT This 64year-old woman, having suffered from occipitalgia for 5 days, was transferred to our service. She showed only neck stiffness neurologically and was diagnosed by CT scan as having SAH. Cerebral angiograms revealed an unusual aneurysmal dilatation of the right vertebral artery at a site distal to the PICA, and a retention of contrast medium in the
aneurysm in the venous phase (Figure 1 A, B, C). Anteroposterior view of the right vertebral angiogram also showed the arterial dilatation exactly in the middle portion of the medulla oblongata (Figure 1 B). The patient was diagnosed as having WI-I due 655 Avenue
0 1997 by Elsevier Science Inc. of the Americas, New York, NY 10010
Coil Embolization
of Ruptured Dissecting Aneurysm
Surg Neurol 1997;47:476-80
Right vertebral angiorams revealed the unusual aneurysmal dilatation of the right vertebral 0that thePICA in the venous phase (c>. Left vertebral (A, B), and retention of contrast medium left vertebral artery was almost equal to the right vertebral artery in caliber (D). (arrow)
to rupture of a dissecting vertebral aneurysm. The right vertebral artery was almost equal to the left one in caliber (Figure 1 D), and there were no perforating branches on the right vertebral artery between the aneurysm and the PICA (Figure 1 B). Temporary balloon occlusion of right vertebral artery at the V2 portion for 20 minutes with systemic heparinization caused no ischemic signs at all. Seven hundred and forty MBq of 99m Tchexamethylene propylene amine oxime (99m TcHMPAO) was injected intravenously 5 minutes after the balloon inflation. The single photon emission computed tomography (SPECT) study performed immediately after the balloon deflation showed no decreased perfusion area in the cerebellum, brain stem, or bilateral posterior lobe. A 6-F guiding catheter (Toray, Tokyo) was inserted into the right vertebral artery via the right femoral artery, and a Tracker 18 catheter (Target Therapeutics) was introduced into the dissection coaxially with systemic heparinization (5000 U). Five IDCs (5 mm-15 cm, 1; 3 mm-6 cm, 2; 3 mm-3 cm, 2) were inserted and released. The aneurysm and its proximal vertebral artery between the aneurysm and the right
477
artery distal to the angiogram showed
PICA were occluded (Figure 2). After the procedure, heparinization was reversed by intravenous administration of protamine sulfate, and antiplatelets were administered. The patient’s postoperative course was uneventful and she was discharged
Right vertebral angiogram showed complete occluqwith IDCs sion of the right vertebral artery distal to the PICA that were packed in the dissection site and the proximal portion of the vertebral artery.
478
Surg Neurol 1997;47:476-80
Follow-up right vertebral angiogram taken 3 months after the embolization, showed no change from that taken just after the embolization procedure, except that the PICA became rather dilated.
without any neurologic deficit on the 25th day after the occlusion. Follow-up angiograms taken 3 months after the embolization revealed complete occlusion of the right vertebral artery distal to the PICA (Figure 3).
DISCUSSION Although dissecting aneurysms of the vertebral artery have been noted to cause SAH, the exact incidence of rupture of vertebral artery dissections is still unclear. There are reports that 28% of 94 vertebral aneurysms were the dissecting type with 81% incidence of rupture [24], and that 45% of 110 autopsied patients with SAH were cases with rupture of a vertebral artery dissection [ 181. These reports suggest the incidence of ruptured vertebral artery dissection might be higher than we assumed. The rebleeding rate of ruptured vertebral artery dissections is said to be 24% [24], 30% [2], or 71.4% [14], and to occur mostly during the acute stage [2,14, 251. Therefore, surgical or endovascular treatment in the acute stage may be important for prevention of rerupture [ 2,8,14]. As vertebral artery dissections are usually fusiform, treatment options are proximal clipping, proximal endovascular occlusion, wrapping, or trapping [3,4,6,8,21,22,24]. Wrapping is recommended only for cases that fail of occlusion test of the affected vertebral artery [24,25], and proximal clipping is most widely accepted for cases that pass the test [24,25]. The goal of treatment of the ruptured dissecting aneurysms is isolation of the dissection site from the circulation to prevent rerupture [lo]. Although proximal clipping has met with
Manabe et al
a good clinical result in many cases, it might not be sufficient to achieve the goal. Three cases with rerupture of ruptured vertebral dissecting aneurysms located at the distal portion of the PICA, occurred after treatment by proximal clipping either distal or proximal to the PICA, were reported [2,6,10]. And another suggestive case was also reported, in which sudden swelling of a vertebral dissecting aneurysm distal to the PICA had occurred during surgery just after the vertebral artery had been clipped between the PICA and the aneurysm [9]. Those four cases were finally treated by trapping, and gave us a suggestion that contralateral retrograde flow may cause a rerupture after proximal clipping of the affected vertebral artery either proximal or distal to the PICA [lo]. Sasaki et al. divided vertebral dissections into two groups based on the clinical and pathologic features: (1) an aneurysm of which the dissection is confined to the vertebral artery, and (2) an aneurysm of which the dissection extended to the basilar artery [ 181. In the former group, the major clinical feature is SAH due to rupture of all three layers of the arterial wall. Such a dissection occurs usually in the subadventitial layer. In the latter, on the other hand, the major pathognomonic factor is a brain stem infarction due to luminal occlusion by intramural hematoma. They assumed that the dissection occurs initially between the intima and media, which is followed sometimes by destruction of all layers of arterial wall and induces SAH. The dissection confined within the arterial wall may cause a luminal occlusion. These pathologic fmdings of ruptured dissecting aneurysms suggest that proximal occlusion might leave the possibility of rebleeding in cases with rich contralateral retrograde filling. Angiographic findings of vertebrobasilar dissecting aneurysms are characteristic, and are divided generally into three categories: (1) those showing changes of the original arterial lumen by intramural hematoma, such as a rosette-shaped opaque area [15,19], “string sign” [17], and fusiform aneurysm with proximally and distally narrowed sections [23]; (2) those showing pseudolumen, such as retention of contrast medium in the late angiographic phase [ 11, “pea-sized oblong bulge” [5], and double lumina as evidenced by different density of contrast material [ 111; (3) and those showing a dissected arterial wall by a flap of intimal layer [ 161. A decisive diagnostic angiographic finding is a double lumen, which is a radical pathologic condition of a dissecting aneurysm [ 20,251. Contrast medium retention in the venous phase seen in our case may indicate the dissected and ruptured region.
Coil Embolization
of Ruptured Dissecting Aneurysm
For cases that are tolerant of parent artery occlusion, trapping should first be considered. In our case, however, direct surgery may have been difficult because of its location and also, in a proximal occlusion either distal or proximal to the PICA, there would remain the risk of rebleeding because the dissection itself could not be occluded [22]. Eventually, the dissection site was occluded by endovascular therapy with IDCs. IDC is a safe endovascular occlusion material for aneurysms or blood vessels, and is detached from the pusher wire by mechanical force [7]. Two major characteristics of the IDC are: (1) its interventional advance and retraction are easy; and (2) its detachment is very quick [ 71. We could easily guide the IDCs to the dissection site with less mechanical stress on the aneurysm wall, and succeed in occluding a short segment including the dissection site and its proximal part of the vertebral artery without ischemic complications. As in our case, the occlusion of the vertebral artery must be kept as short as possible in order to avoid the occlusion of perforators to the brain stem, because there are O-3 (mean: 0.5) tiny perforating branches originating from the vertebral artery at the proximal segment to the PICA, and O-5 (mean: 1.8) perforators at the distal segment to the PICA [12]. Occlusion of any of those perforators causes
medullary
infarction
[3,24].
Perforating
branches originating from the vertebral artery at the distal segment of the occlusion will be supplied by retrograde filling. But anticoagulation therapy should be started immediately after the occlusive procedure to prevent unexpected progressive thrombosis in the distal segment [8], which may occlude the perforating branches and cause medullary infarction [ 251.
Surg Nemo1 1997;47:476-80
6. 7.
8.
9.
10. 11. 12. 13.
14.
15. 16.
17.
REFERENCES 1. Anderson RM, Schechter MM. A case of spontaneous dissecting aneurysm of the internal carotid artery. J Neurol Neurosurg Pyschiatry 1959;22:195201. 2. Aoki N, Sakai T. Rebleeding from intracranial dissecting aneurysm in the vertebral artery. Stroke 1990;21: 1628-31. 3. Aymard A, Gobin YP, Hodes JE, Bien S, Rufenacht D, Reizine D, George B, Merland JJ. Endovascular occlusion of vertebral arteries in the treatment of unclippable vertebrobasilar aneurysms. J Neurosurg 1991; 74:393-g. 4. Berger MS, Wilson CB. Intracranial dissecting aneurysms of the posterior circulation. J Neurosurg 1984; 61:882-94. 5. Bostrom K, Liliequist B. Primary dissecting aneurysm of the extracranial part of the internal carotid and
18.
19. 20. 21.
22.
479
vertebral arteries. A report of three cases. Neurology 1967;17:179-86. Friedman AH, Drake CC. Subarachnoid hemorrhage from intracranial dissecting aneurysm. J Neurosurg 1984;60:325-34. Guglielmi G, Vinuela F, Sepetka I, Macellari V. Electrothrombosis of saccular aneurysms via endovascular approach. Part 1: electrochemical basis, technique, and experimental results. J Neurosurg 1991; 75:1-7. Halbach W, Higashida RT, Dowd CF, Fraser KW, Smith TP, Teitelbaum GP, Wilson CB, Hieshima GB. Endovascular treatment of vertebral artery dissections and pseudoaneurysms. J Neurosurg 1993;79: 183-91. Irikura K, Miyasaka Y, Ohtaka H, Yada K, Hirose R. Dissecting aneurysm of the vertebral artery with lateral medullary syndrome. A case report, with special reference to surgical treatment. (in Japanese) Jpn J Stroke 1989;11:113-39. Kitanaka C, Morimoto T, Sasaki T, Takakura K. Rebleeding from vertebral artery dissection after proximal clipping. J Neurosurg 1992;77:466-8. Kunze S, Schiefer W. Angiographic demonstration of a dissecting aneurysm of the middle cerebral artery. Neuroradiology 1971;2:201-6. Lister JR, Rhoton AL, Matsushima T, Peace DA. Microsurgical anatomy of the posterior inferior cerebellar artery. Neurosurgery 1982; 10: 170-99. Marks MP, Chee H, Liddell RP, Steinberg GK, Panahian N, Lane B. A mechanically detachable coil for the treatment of aneurysms and occlusion of blood vessels. AJNR 1994;15:825-27. Mizutani T, Aruga T, Kirino T, Miki Y, Saito 1,Tsuchida T. Recurrent subarachnoid hemorrhage from untreated ruptured vertebrobasilar dissecting aneurysms. Neurosurgery 1995;36:905-13. Nelson JW. Dissecting subintimal hematomas of the intracranial arteries. Report of a case. J Am Osteopath Assoc 1968;67:512-27. New PFJ, Momose KJ. Traumatic dissection of the internal carotid artery at the atlatoaxial level, secondary to nonpenetrating injury. Radiology 1969;93:4149. Ojemann RG, Fisher CM, Rich JC. Spontaneous dissecting aneurysm of the internal carotid artery. Stroke 1972;3:434-40. Sasaki 0, Ogawa H, Koike T, Koizumi T, Tanaka R. A clinicopathological study of dissecting aneurysms of the intracranial vertebral artery. J Neurosurg 1991;75: 874-82. Scott GE, Neubuerger KT, Denst F. Dissecting aneurysms of intracranial arteries. Neurology 1960;10:2227. Shimoji T, Bando K, Nakajima K, Ito K. Dissecting aneurysm of the vertebral artery. J Neurosurg 1984; 61:1038-46. Takahashi A, Sugawara T, Suga T, Su CC, Kawakami K, Yoshimoto T. Detachable balloon treatment of dissecting vertebral aneurysm in its acute stage of sub arachnoid hemorrhage (in Japanese). Surgery Cerebral Stroke 1989;17:44-48. Tsukahara T, Wada H, Satake K, Yaoita H, Takahashi A. Proximal balloon occlusion for dissecting vertebral
480
Surg Neurol 1997;47:476-80
Manabe et al
aneurysms accompanied by subarachnoid hemorrhage. Neurosurgery 1995;36:914-20. 23. Waga S, Fujimoto K, Morooka Y. Dissecting aneurysm of the vertebral artery. Surg Neurol 1978;lO: 237-9. 24. Yamaura A. Diagnosis and treatment of vertebral aneurvsms. J Neurosure 1988:69:345-g. 25. Yamaura A, Watanabe Y, Saeki N. Dissecting aneurysms of the intracranial vertebral artery. J Neurosurg 1990;72:183-8.
66 Is
COMMENTARY I think this is an interesting case, appropriately treated with retrievable coils. The risks with a detached balloon would have been higher (e.g., dissection, rupture, occlusion of perforators).
URGICAL NEUROLOGY'S" [email protected]
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Gerard Debrun,M.D. Chicago, Illinois
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