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Treatment strategy for giant aneurysms in the cavernous portion of the internal carotid artery
Surgical Neurology 67 (2007) 148 – 155 www.surgicalneurology-online.com
Aneurysm
Treatment strategy for giant aneurysms in the cavernous portion of the internal carotid artery Yutaka Kaia,4, Jun-ichiro Hamadab, Motohiro Moriokaa, Shigetoshi Yanoa, Takamasa Mizunoa, Jun-ichiro Kurodaa, Tatemi Todakaa, Hideo Takeshimaa, Jun-ichi Kuratsua b
a Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan Department of Neurosurgery, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa 860-8556, Japan Received 28 November 2005; accepted 31 March 2006
Abstract
Background: As direct surgery to treat giant aneurysms of the ICA is difficult, ICA occlusion is the conventional treatment in patients with BTO tolerance. To determine whether bypass surgery should be performed after carotid occlusion by trapping or proximal occlusion, we developed a treatment strategy that includes BTO and SPECT. Methods: We report 19 patients with symptomatic giant aneurysms in the cavernous portion of ICA. The appropriate type of bypass surgery was determined by the results of BTO and SPECT. The type of ICA occlusion selected was based on the evaluation of retrograde filling of the aneurysm during BTO. Results: In all 19 patients, the ICA was sacrificed; 10 patients also underwent bypass surgery (lowflow bypass with STA-MCA anastomosis, n = 7; medium-flow bypass with radial artery graft, n = 2; high-flow bypass with vein graft, n = 1). Coil trapping was performed in 11 patients; proximal occlusion in 8. In 18 patients, there were no ischemic complications after treatment; 1 patient who had been treated by proximal ICA occlusion developed transient ischemia due to an intra-aneurysmal thrombus. Cranial nerve palsies were improved in 16 patients. Conclusions: Based on our experience, we recommend that patients with giant aneurysms in the cavernous portion of the ICA be evaluated by BTO and SPECT. In conjunction with bypass surgery, ICA trapping or proximal occlusion constitutes an effective treatment strategy. D 2007 Elsevier Inc. All rights reserved.
Keywords:
Cerebral aneurysm; Internal carotid artery; Balloon test occlusion; Bypass; Interventional neurosurgery
1. Introduction The mass effect attendant to giant aneurysms arising from the cavernous portion of the ICA may produce compression of the adjacent third to sixth cranial nerves and result in symptoms such as headache and pain.
Abbreviations: BTO, balloon test occlusion; CBF, cerebral blood flow; ECA, external carotid artery; ICA, internal carotid artery; GDC, Guglielmi detachable coils; MRI, magnetic resonance imaging; MRA, magnetic resonance angiography; RI, radioisotope; SAH, subarachnoid hemorrhage; SPECT, single photon emission computed tomography; STA-MCA, superficial temporal artery to middle cerebral artery; 99mTc-HMPAO, hexomethyl propylene amine oxime. 4 Corresponding author. Tel.: +81 96 373 5219; fax: +81 96 371 8064. E-mail address: [email protected] (Y. Kai). 0090-3019/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2006.03.037
Moreover, if the aneurysm extends into the subarachnoid space, SAH may occur [1,5,6,19]. As direct surgery to treat giant ICA aneurysms is difficult, ICA occlusion is the conventional treatment in patients with BTO tolerance [2,3,8,13,24]. Concurrent with advancements in endovascular techniques, many diagnostic tests have been developed to evaluate the risk of ischemic infarction from carotid occlusion before permanent ICA sacrifice. The most widely accepted of these is BTO [20]. At our institute, we use BTO results to determine whether bypass surgery between ICA and ECA should be performed after carotid occlusion by endovascular techniques (balloon or coils) or direct surgery. Here we report 19 patients with giant aneurysms arising from the cavernous portion of the ICA. They were successfully treated by our
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Fig. 1. A: Left internal carotid angiogram showing a giant aneurysm in the cavernous portion of the left internal carotid artery. B: Superselective angiogram demonstrating the distal site of the aneurysmal orifice (arrow) and the ophthalmic artery (arrowheads). The distance between the origin of the ophthalmic artery and the distal site of the aneurysmal orifice is clearly seen.
strategy, which includes BTO and SPECT examination and ICA occlusion by trapping or proximal occlusion. 2. Material and methods Between 1995 and 2004, 19 patients with a giant aneurysm in the cavernous portion of the ICA were treated at our department. There were 2 males and 17 females ranging in age from 43 to 75 years (mean, 62.8 years). Their clinical presentation included mass effect with symptoms of diplopia (n = 16), retro-orbital pain (n = 1), and visual disturbance (n = 2). Diagnostic, high-magnification cerebral, and rapid-sequence digital subtraction angiograms (DSAs) were obtained to assess the aneurysmal size and shape, and the relationship of the aneurysm neck to the ICA. The aneurysms ranged from 20 to 36 mm (mean, 27.8 mm). In 13 patients, MRI revealed aneurysmal wall thrombosis. To develop a treatment strategy, 30-minute BTO was carried out. In general, a 4-vessel cerebral angiogram was obtained after complete neurologic examination to determine baseline values. A 5-Fr double-lumen occlusion balloon catheter (Celecon multi-catheter, Clinical Supply Co Ltd, Tokyo, Japan) was introduced into the femoral artery and advanced to the ICA at the level of the C2 vertebral bodies. An intravenous 5000-U bolus of heparin was injected, and the balloon was inflated until a decrease in distal ICA pressure was recorded. Upon completion of ICA
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occlusion, contrast material was injected through a 4-Fr catheter introduced into a femoral artery to confirm complete occlusion of the ICA. In 2 patients whose vasculature was highly tortuous, the balloon was introduced into the common carotid artery by direct puncture using a 5-Fr introducer. These patients underwent continuous neurologic evaluation during the first 5 minutes of BTO followed by examinations at 5-minute intervals. Balloon inflation was maintained for 30 minutes. In patients who developed neurologic deficits, the balloon was deflated immediately, and the contralateral ICA, ipsilateral ECA, and dominant vertebral artery were studied to assess the collateral circulation across the circle of Willis to detect retrograde filling of the aneurysm. Moreover, the distal pressure in the balloon catheter was continually monitored during TBO occlusion. For correct placement of the first coil, the precise distance between the ophthalmic artery and the distal site of the aneurysmal orifice must be known. Therefore, using a microcatheter, we obtained angiograms during BTO (Fig. 1). In patients who did not develop neurologic deficits in the course of 30-minute BTO, the balloon was deflated but not removed and the patient was taken to the RI suite. There it was reinflated, and CBF study was performed. Single photon emission computed tomograms using 99m TcHMPAO were obtained. After completion of the first scan within less than 10 minutes, stress was induced with an intravenous injection of 1 g acetazolamide. At 5 minutes after the second intravenous delivery of 99mTc-HMPAO, a second scan was performed; the balloon remained inflated throughout these procedures (Fig. 2). Fig. 3 shows our method of carotid artery occlusion with selective revascularization. Patients with clinical evidence of profound ischemia during BTO may require a high-flow bypass with vein grafting before ICA sacrifice. In patients without ischemic symptoms during BTO, at-rest SPECT study may demonstrate hypoperfusion of the hemisphere ipsilateral to the occlusion site. These patients may require a medium-flow bypass with radial artery grafting. Alternatively, SPECT study may demonstrate normal perfusion at rest and hypo-vasoreactivity of the hemisphere ipsilateral to the occlusion site during acetazolamide stress. These patients may require a low-flow bypass (STA-MCA bypass). Patients
Fig. 2. Time course of BTO and at-rest and acetazolamide-stressed SPECT procedures.
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Fig. 3. Management algorithm for giant cavernous sinus aneurysms in the internal carotid artery. Dx indicates diamox.
who tolerate BTO of the ICA and manifest no hypoperfusion on SPECT study at rest and during acetazolamide stress can be treated by sacrificing the ICA without a bypass. We usually sacrifice the ICA using several detachable coils. If there is retrograde filling of the aneurysm from collateral flow, we perform ICA sacrifice by trapping on both sides of the aneurysmal orifice. In the absence of retrograde filling, we sacrifice the ICA by proximal occlusion (Fig. 4). In patients who underwent ICA sacrifice and required a bypass, we first performed extracranial-intracranial bypass surgery in the operating room. Selection of the appropriate type of bypass was based on BTO- and SPECT findings. The ICA was sacrificed after bypass surgery. In patients in whom
treatment called for ICA trapping, the cervical ICA was exposed, punctured with a 3-Fr introducer, and a microcatheter (Boston Scientific, Target, Fremont, Calif) was inserted. Its tip was positioned at the distal site of the aneurysmal orifice. Portable DSA equipment was used during the procedures. After clamping the proximal site of the ICA with a Sugita aneurysmal clip, its distal site was occluded with several GDCs (GDC-18, Boston Scientific, Tokyo, Japan). Then the proximal site was occluded using 5-0 silk sutures. In patients who did not require ICA trapping, the cervical ICA was exposed and directly occluded with 5-0 Fr silk sutures. Patients who did not require bypass surgery (n = 9) underwent sacrifice of the ICA in the operating room under
Fig. 4. Management algorithm for internal carotid artery occlusion.
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3. Representative cases
aneurysm (Fig. 5B). She underwent BTO of the left cervical carotid artery without neurologic consequences. Because there was retrograde filling of the aneurysmal lumen (Fig. 5C), we concluded that trapping was necessary to treat this aneurysm. During BTO of the ICA, the at-rest SPECT scan revealed normal perfusion; vasoreactivity after acetazolamide stress was also normal (Fig. 5D and E). Therefore, she did not require anastomosis. The left cervical ICA was exposed in the operating room and punctured with a 3.0-Fr introducer using intraoperative DSA. Embolization with several GDC-18 was performed at a point just beyond the distal site of the aneurysmal orifice, and the proximal site of the left ICA at the cervical bifurcation was occluded with silk sutures. This resulted in complete trapping of the left ICA. Her postoperative course was uneventful with early, marked improvement in her previous double vision. Postoperative MRA, performed a week later, demonstrated the absence of aneurysmal filling (Fig. 5F). An MRI scan, obtained 3 weeks after the operation, showed the aneurysm to be thrombosed (Fig. 5G).
3.1. Case 1
3.2. Case 2
This 49-year-old woman, admitted 2 weeks after the onset of double vision, manifested partial paresis of the left oculomotor nerve. Magnetic resonance imaging showed a mass lesion in the left cavernous sinus (Fig. 5A); angiography showed a large left intracavernous ICA
This 51-year-old woman, admitted a month after the onset of double vision, manifested partial left oculomotor palsy. Magnetic resonance imaging disclosed a mass lesion in the left cavernous sinus (Fig. 6A); angiography showed a large left intracavernous ICA aneurysm (Fig. 6B). She
general anesthesia. When coil trapping was needed for ICA occlusion, this was achieved. The patients spent the first 24 hours after surgery in the intensive care unit under constant monitoring of their hydration status, blood pressure, and neurologic signs. During the first 48 hours, they received low-dose heparin therapy. On the second day, the oral administration of antiplatelet agents (aspirin or ticlopidine) was started; it was continued to prevent the formation of emboli from the thrombosing aneurysm. The treatment of patients manifesting ischemic complications includes therapeutic hyperperfusion and volume expansion. All patients underwent routine pre- and postoperative neuro-ophthalmologic evaluation and detailed neurologic examinations at 1 to 4 weeks after carotid artery occlusion and then at 3- to 6-month intervals (mean, 15.3 months; range, 3.4-39.4 months). Pre- and postoperative neurologic deficits were compared. All patients also underwent MRI at least 1 month after carotid artery occlusion.
Fig. 5. A: Preoperative T1-weighted magnetic resonance image demonstrating an intracavernous aneurysm. B: Preoperative left internal carotid angiogram demonstrating an intracavernous aneurysm. C: Right internal carotid angiogram demonstrating retrograde filling of the aneurysm via the anterior communicating artery. D: At-rest 99mTc-HMPAO–SPECT scan obtained during BTO. There is no laterality in the cerebral blood flow. E: 99mTc-HMPAO–SPECT scan obtained after acetazolamide administration during BTO. There is no laterality in the cerebral blood flow. F: The aneurysm is not visualized on this postoperative magnetic resonance angiogram. G: Postoperative T1-weighted magnetic resonance image demonstrating that the intracavernous aneurysm is thrombosed.
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Fig. 6. A: Preoperative T1-weighted magnetic resonance image demonstrating an intracavernous aneurysm. B: Preoperative left internal carotid angiogram demonstrating an intracavernous aneurysm. C: Left external carotid angiogram demonstrating retrograde filling of the aneurysm via the left ophthalmic artery. D: At-rest 99mTc-HMPAO–SPECT scans obtained during BTO. There is laterality in the cerebral blood flow on the left side. E: 99mTc-HMPAO–SPECT scans obtained after acetazolamide administration during BTO. The blood flow in the territory of the left middle cerebral artery is reduced. F: Postoperative left common carotid angiogram showing the arterial bypass to be widely patent. No aneurysm is visualized and the left internal carotid artery is occluded. G: Postoperative T1-weighted magnetic resonance image demonstrating that the intracavernous aneurysm is thrombosed.
underwent BTO of the left cervical carotid artery without neurologic consequences. As BTO showed retrograde filling of the aneurysmal lumen (Fig. 6C), we concluded that aneurysmal trapping was necessary in this patient. A SPECT scan obtained during BTO of the ICA disclosed hypoperfusion at rest and a severe decrease in the left compared to the right hemisphere perfusion upon acetazolamide stressing (Fig. 6D and E). These findings indicated that medium-flow bypass with radial artery grafting was required. We performed anastomosis with a radial artery graft between the cervical portion of the left ECA and the M2 portion of the left middle cerebral artery; intraoperative angiography confirmed patency of the bypass graft. The
distal site of the left ICA was occluded with a clip placed just proximal to the left ophthalmic artery bifurcation because examination of the BTO results showed the distance between the ophthalmic artery and the distal site of the aneurysmal orifice to be very short. The proximal site was occluded with silk sutures just distal to the cervical bifurcation. As a result of these procedures, the left ICA was completely trapped. Her postoperative course was uneventful with early marked improvement in her double vision. Angiography performed 1 week later demonstrated a widely patent graft without aneurysmal filling (Fig. 6F). An MRI scan obtained 2 weeks after the operation revealed a thrombosed aneurysm (Fig. 6G).
Table 1 Results of our treatment strategy to address giant aneurysms in the cavernous portion of the internal carotid artery BTO
Tolerance Tolerance Tolerance Intolerance
SPECT
At rest: normal After Dx: normal At rest: normal After Dx: poor vasoreactivity At rest: hypoperfusion After Dx: poor vasoreactivity ( )
Dx indicates diamox. a Embolism after treatment.
Bypass
Retrograde filling ( )
Retrograde filling (+)
Proximal occlusion
Trapping
( )
4
5a
STA-MCA
4
3
Radial artery graft
0
2
Vein graft
0
1
Y. Kai et al. / Surgical Neurology 67 (2007) 148 – 155
4. Results All but 1 of the 19 patients tolerated BTO without developing any neurologic deficits. One patient experienced consciousness disturbance immediately after the start of the test; her symptoms improved after balloon deflation. Of the other patients, 2 manifested mild hypoperfusion on at-rest SPECT scans, 7 had normal perfusion on at-rest SPECT scans but manifested hypo-vasoreactivity after acetazolamide administration, and 9 demonstrated normal perfusion on at-rest SPECT scans and after acetazolamide stressing. Based on these findings 10 patients underwent bypass surgery before ICA sacrifice. One patient received a highflow bypass using a saphenous vein, 2 a medium-flow bypass using a radial artery graft, and 7 a low-flow bypass using STA-MCA anastomosis. The remaining 9 patients underwent sacrifice of the ICA only (Table 1). In 11 patients, BTO demonstrated retrograde filling of the aneurysm by collateral flow. Although we attempted ICA trapping in these cases, in 1 patient coil trapping was not possible because we were unable to pass the microcatheter through the distal orifice of the aneurysm. Therefore, this patient underwent only proximal ligation (Fig. 7A). Despite anticoagulant therapy, she had a transient ischemic complication due to an embolic episode (Fig. 7B) and underwent direct surgery. The distal site of the ICA was occluded with a clip applied between the proximal site of the ophthalmic artery and the distal orifice of the aneurysm, and the left ICA was trapped 1 day after proximal occlusion of the ICA. Her ischemic complication subsequently disappeared, and several days post-treatment her mild leftsided hemiparesis resolved. On T1-weighted MRI scans, all patients manifested posttreatment thrombosis in the aneurysmal space. At 6 months, all had a good outcome as judged by the Glasgow outcome scale, and at approximately 3 to 6 months post-treatment, all demonstrated significant improvement in their neurologic symptoms. Among the 16 patients with preoperative double vision, this symptom completely disappeared in 5, improved in 9, and was without change in 2. In 2 patients with visual disturbance and 1 with facial dysesthesia, there was a slight improvement. In the group
Fig. 7. A: Left internal carotid angiogram showing an aneurysm in the cavernous portion. B: Postoperative diffusion-weighted magnetic resonance image demonstrating multiple hyperintensity areas in the left parietal region.
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with complete postoperative resolution of their neurologic symptoms, the median interval between symptom onset and treatment was 2.2 months. This interval was 4.8 months in patients who exhibited some residual symptoms. 5. Discussion In patients with giant ICA aneurysms, neurosurgic approaches are often unsuitable and the majority of reported cases were managed by carotid ligation procedures [8]. The morbidity and mortality rate of patients whose intracranial carotid artery aneurysms were treated by ICA ligation was between 10% and 20% [23]. To reduce ischemic complications due to proximal vessel occlusion, collateral flow is provided via several types of bypass surgery [13,16,25]. It is very important to evaluate the risk of infarction from carotid occlusion before permanent ICA sacrifice. Before the introduction of BTO, approximately 25% of patients developed infarctions after, and 12% died as a result of occlusion [20]. Although the widely accepted BTO contributed to the marked decrease in the stroke rate after carotid occlusion [2,5,9,11], a significant percentage of patients with acceptable BTO results developed infarction [7,20]. Other techniques used in combination with BTO include quantitative CBF analysis (eg, SPECT with HMPAO). The addition of physiologic stressors (eg, induced hypotension, acetazolamide injection) may aid in the identification of patients with compromised cerebrovascular reserves [26,27]. Our treatment strategy of bypass selection based on BTO and SPECT results provides more exacting criteria than previously reported methods. Patients with BTO evidence of profound ischemia may require a high-flow venous bypass graft before ICA sacrifice. In some patients without ischemic symptoms during BTO, at-rest SPECT study demonstrates hypoperfusion in the hemisphere ipsilateral to the occlusion site. These patients may require a medium-flow bypass. Alternatively, in some cases, despite the absence of ischemic symptoms during BTO and the demonstration of normal atrest SPECT results, under acetazolamide stress, there is hypo-vasoreactivity of the hemisphere ipsilateral to the occlusion site. These patients may require a low-flow (STAMCA) bypass. Only patients who tolerate BTO and manifest no hypoperfusion on at-rest and acetazolamide-stressed SPECT study during ICA occlusion can be treated by sacrificing the ICA without a bypass. In our series, we encountered no patients with ischemic complications after ICA occlusion. However, 1 patient had a thromboembolic complication after proximal ligation of the ICA. In this patient, we recognized retrograde filling of the aneurysm via the collateral circulation during BTO. Although occlusion of this ICA appeared to require trapping, we were able to occlude the ICA by proximal ligation. Most intracavernous aneurysms treated by proximal occlusion thrombosed and the symptoms of cranial nerve dysfunction resolved slowly over several months. However, in some patients there was retrograde flow to the aneurysm
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from the ophthalmic artery after ICA ligation. In these cases, proximal occlusion may not produce complete thrombosis of the aneurysm and there is a risk of microemboli from the intra-aneurysmal thrombus to the distal ICA [10]. According to some studies [4,12,17,18], balloon-trapping procedures carry a decreased risk of thromboembolic complications compared with proximal balloon ligation. However, the positioning of detachable balloons is sometimes difficult, primarily because no satisfactory detachment mechanism is currently available and it remains very difficult to occlude the ICA on either side of the aneurysmal orifice with detachable balloons. Therefore, detachable coils [14,15] are superior because their precise detachment is possible [21,22]. We found that detachable coils can be placed accurately to occlude both the distal and proximal site of the orifice of aneurysms in the parent ICA and that retrograde filling completely disappeared after placing a coil just proximal to the ophthalmic artery. The correct placement of the first coil requires knowledge regarding the precise distance between the ophthalmic artery and the distal site of the aneurysmal orifice. Therefore, we obtained angiograms using a microcatheter during BTO (Fig. 1). If the distance between the ophthalmic artery and the distal site of the aneurysmal orifice is not sufficient for placement of the first coil, retrograde flow to the aneurysm may continue via the ophthalmic artery. In such cases, we avoid proximal occlusion only and attempt to include the origin of the ophthalmic artery if the vessel is supplied by collateral flow from the ECA. Ezura et al [10] emphasized that combined occlusion of the parent and ophthalmic artery is effective in giant aneurysms located between the ophthalmic and the posterior communicating artery. In another series, we will perform craniotomy and attempt to occlude the distal ICA with a clip. However, as this technique requires exposure of the ICA proximal to the bifurcation of the ophthalmic artery, these patients have to undergo skull base surgery. Of the 19 patients reported here, 16 were monitored by postocclusion follow-up lasting more than 1 year. Improvement of pre-treatment symptoms was noted in 14 (87.5%) of the 16 patients. Double vision persisted in 11 patients (57.9%), although in 9 this symptom was milder and 2 reported no change. Posttreatment, 5 patients were completely asymptomatic with normal neurologic examinations. As the median interval between symptom onset and treatment was shorter in the group with complete symptom resolution, we conclude that early treatment is important in patients with giant aneurysms in the cavernous portion of the ICA. We suggest that treatment should be delivered within 3 months of symptom onset. 6. Conclusion In patients with giant aneurysms in the cavernous portion of the ICA, BTO and SPECT results must be carefully analyzed before ICA occlusion. We found that ICA trapping
or proximal occlusion combined with bypass surgery was an effective treatment strategy. References [1] Al-Rodhan NR, Piepgras DG, Sundt Jr TM. Transitional cavernous aneurysms of the internal carotid artery. Neurosurgery 1993;33:993 - 6. [2] Barnett DW, Barrow DL, Joseph GJ. Combined extracranialintracranial bypass and intraoperative balloon occlusion for the treatment of intracavernous and proximal carotid artery aneurysms. Neurosurgery 1994;35:92 - 7. [3] Bavinzski G, Killer M, Ferraz-Leite H, Gruber A, Gross CE, Richling B. Endovascular therapy of idiopathic cavernous aneurysms over 11 years. AJNR Am J Neuroradiol 1998;19:559 - 65. [4] Berenstein A, Ransohoff J, Kupersmith M, Flamm E, Graeb D. Transvascular treatment of giant aneurysms of the cavernous carotid and vertebral arteries. Functional investigation and embolization. Surg Neurol 1984;21:3 - 12. [5] Date I, Ohmoto T. Long-term outcome of surgical treatment of intracavernous giant aneurysms. Neurol Med Chir (Tokyo) 1998; 38(Suppl):62 - 9. [6] Debrun G, Fox A, Drake C, Peerless S, Girvin J, Ferguson G. Giant unclippable aneurysms: treatment with detachable balloons. AJNR Am J Neuroradiol 1981;2:167 - 73. [7] Diaz FG, Ausman JI, Pearce JE. Ischemic complications after combined internal carotid artery occlusion and extracranial-intracranial anastomosis. Neurosurgery 1982;10:563 - 70. [8] Drake CG, Peerless SJ, Ferguson GG. Hunterian proximal arterial occlusion for giant aneurysms of the carotid circulation. J Neurosurg 1994;81:656 - 65. [9] Erba SM, Horton JA, Latchaw RE, Yonas H, Sekhar L, Schramm V, Pentheny S. Balloon test occlusion of the internal carotid artery with stable xenon/CT cerebral blood flow imaging. AJNR Am J Neuroradiol 1988;9:533 - 8. [10] Ezura M, Takahashi A, Yoshimoto T. Combined intravascular parent artery and ophthalmic artery occlusion for giant aneurysms of the supraclinoid internal carotid artery. Surg Neurol 1997;47:360 - 3. [11] Field M, Jungreis CA, Chengelis N, Kromer H, Kirby L, Yonas H. Symptomatic cavernous sinus aneurysms: management and outcome after carotid occlusion and selective cerebral revascularization. AJNR Am J Neuroradiol 2003;24:1200 - 7. [12] Fox AJ, Vinuela F, Pelz DM, Peerless SJ, Ferguson GG, Drake CG, Debrun G. Use of detachable balloons for proximal artery occlusion in the treatment of unclippable cerebral aneurysms. J Neurosurg 1987;66:40 - 6. [13] Gelber BR, Sundt Jr TM. Treatment of intracavernous and giant carotid aneurysms by combined internal carotid ligation and extra- to intracranial bypass. J Neurosurg 1980;52:1 - 10. [14] Guglielmi G, Vinuela F, Dion J, Duckwiler G. Electrothrombosis of saccular aneurysms via endovascular approach: Part 2. Preliminary clinical experience. J Neurosurg 1991;75:8 - 14. [15] 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. [16] Heros RC, Nelson PB, Ojemann RG, Crowell RM, DeBrun G. Large and giant paraclinoid aneurysms: surgical techniques, complications, and results. Neurosurgery 1983;12:153 - 63. [17] Higashida RT, Halbach VV, Barnwell SL, Dowd C, Dormandy B, Bell GB, Hieshima GB. Treatment of intracranial aneurysms with preservation of the parent vessel: results of percutaneous balloon embolization in 84 patients. AJNR Am J Neuroradiol 1990;11:633 - 40. [18] Higashida RT, Halbach VV, Dowd C, Barnwell SL, Dormandy B, Bell J, Hieshima GB. Endovascular detachable balloon embolization therapy of cavernous carotid artery aneurysms: results in 87 cases. J Neurosurg 1990;72:857 - 63.
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Commentary The authors outline a management algorithm for giant cavernous carotid aneurysms, using information from BTO augmented with SPECT with and without diamox to stratify their treatment strategy. Although there have been proponents of universal revascularization in the setting of carotid occlusion for aneurysms [3], such a nonselective approach imposes the potential for unnecessary morbidity. A selective approach that can accurately identify those patients who are in true need of revascularization and also guide the appropriate revascularization strategy represents the optimal strategy. In this paper, the authors propose just such a selective approach, stratifying patients based upon results of BTO combined with SPECT and diamox challenge. Based upon the severity of hypoperfusion, they perform either vein, radial artery, or STA bypass, reflecting the need for bhigh flow,Q bmedium flow,Q or blow flow.Q In addition, the authors advocate trapping of the aneurysm over proximal occlusion if retrograde filling of the aneurysm is angiographically evident.
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In our own institution, we also adopt a similar strategy, but using BTO with hypotensive challenge and SPECT, rather than diamox. In addition, we feel that, although the severity of hypoperfusion with BTO can guide the operative plan as to the type of bypass required, the decision regarding the appropriate conduit, and confirmation of adequate flow replacement, should be performed intra-operatively. Our standard practice at the time of surgery in such cases is to perform direct intraoperative measurement of the middle cerebral artery flow during surgery using an ultrasonic flow probe [2]. Reduction in flow is then directly measured during temporary clamping of the proximal ICA. The measured flow deficit is used as the final determinant to choose the appropriate conduit for the bypass. Furthermore, the direct flow measurements provide in situ confirmation of the accuracy of the preoperative BTO protocol. In addition, although vein grafts are typically considered to be bhigh flow,Q even an STA branch may be adequate if the actual flow deficit is known, and the STA flow-carrying capacity (measurable as the free flow from its cut end [1]) is sufficient. As such, we are able to designate the bypass as high, medium, or low flow based upon in situ flow measurement rather than the assumed flow assigned to particular types of bypass conduits. Regarding the authors’ strict requirement for trapping of an aneurysm if retrograde filling is observed, we have generally felt that proximal occlusion is often adequate in such cases as the aneurysm will progress to full thrombosis. Their experience with one patient in the series who had thromboembolism under those circumstances does emphasize the need for careful attention to both antiplatelet and anticoagulant therapy. If trapping is pursued, distal clip occlusion may be preferable to distal coil occlusion from the standpoint of thromboembolic risk, especially in the cases where surgery is already being performed for the purpose of bypass; clip occlusion is generally safe and effective even above the level of the ophthalmic origin, avoiding the need for additional dissection and clinoidectomy. Sepideh Amin-Hanjani, MD Fady T. Charbel, MD Department of Neurosurgery University of Illinois at Chicago Chicago, IL 60612, USA References [1] Amin-Hanjani S, Du X, Mlinarevich N, Meglio G, Zhao M, Charbel FT. The cut flow index: an intraoperative predictor of the success of extracranial-intracranial bypass for occlusive cerebrovascular disease. Neurosurgery 2005;56:75 - 85. [2] Charbel FT, Hoffman WE, Misra M, Ostergren L. Ultrasonic perivascular flow probe: technique and application in neurosurgery. Neurol Res 1998;20:439 - 42. [3] Lawton MT, Hamilton MG, Morcos JJ, Spetzler RF. Revascularization and aneurysm surgery: current techniques, indications, and outcome. Neurosurgery 1996;38:83 - 92 [discussion 92-84].
Aneurysm
Treatment strategy for giant aneurysms in the cavernous portion of the internal carotid artery Yutaka Kaia,4, Jun-ichiro Hamadab, Motohiro Moriokaa, Shigetoshi Yanoa, Takamasa Mizunoa, Jun-ichiro Kurodaa, Tatemi Todakaa, Hideo Takeshimaa, Jun-ichi Kuratsua b
a Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan Department of Neurosurgery, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa 860-8556, Japan Received 28 November 2005; accepted 31 March 2006
Abstract
Background: As direct surgery to treat giant aneurysms of the ICA is difficult, ICA occlusion is the conventional treatment in patients with BTO tolerance. To determine whether bypass surgery should be performed after carotid occlusion by trapping or proximal occlusion, we developed a treatment strategy that includes BTO and SPECT. Methods: We report 19 patients with symptomatic giant aneurysms in the cavernous portion of ICA. The appropriate type of bypass surgery was determined by the results of BTO and SPECT. The type of ICA occlusion selected was based on the evaluation of retrograde filling of the aneurysm during BTO. Results: In all 19 patients, the ICA was sacrificed; 10 patients also underwent bypass surgery (lowflow bypass with STA-MCA anastomosis, n = 7; medium-flow bypass with radial artery graft, n = 2; high-flow bypass with vein graft, n = 1). Coil trapping was performed in 11 patients; proximal occlusion in 8. In 18 patients, there were no ischemic complications after treatment; 1 patient who had been treated by proximal ICA occlusion developed transient ischemia due to an intra-aneurysmal thrombus. Cranial nerve palsies were improved in 16 patients. Conclusions: Based on our experience, we recommend that patients with giant aneurysms in the cavernous portion of the ICA be evaluated by BTO and SPECT. In conjunction with bypass surgery, ICA trapping or proximal occlusion constitutes an effective treatment strategy. D 2007 Elsevier Inc. All rights reserved.
Keywords:
Cerebral aneurysm; Internal carotid artery; Balloon test occlusion; Bypass; Interventional neurosurgery
1. Introduction The mass effect attendant to giant aneurysms arising from the cavernous portion of the ICA may produce compression of the adjacent third to sixth cranial nerves and result in symptoms such as headache and pain.
Abbreviations: BTO, balloon test occlusion; CBF, cerebral blood flow; ECA, external carotid artery; ICA, internal carotid artery; GDC, Guglielmi detachable coils; MRI, magnetic resonance imaging; MRA, magnetic resonance angiography; RI, radioisotope; SAH, subarachnoid hemorrhage; SPECT, single photon emission computed tomography; STA-MCA, superficial temporal artery to middle cerebral artery; 99mTc-HMPAO, hexomethyl propylene amine oxime. 4 Corresponding author. Tel.: +81 96 373 5219; fax: +81 96 371 8064. E-mail address: [email protected] (Y. Kai). 0090-3019/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2006.03.037
Moreover, if the aneurysm extends into the subarachnoid space, SAH may occur [1,5,6,19]. As direct surgery to treat giant ICA aneurysms is difficult, ICA occlusion is the conventional treatment in patients with BTO tolerance [2,3,8,13,24]. Concurrent with advancements in endovascular techniques, many diagnostic tests have been developed to evaluate the risk of ischemic infarction from carotid occlusion before permanent ICA sacrifice. The most widely accepted of these is BTO [20]. At our institute, we use BTO results to determine whether bypass surgery between ICA and ECA should be performed after carotid occlusion by endovascular techniques (balloon or coils) or direct surgery. Here we report 19 patients with giant aneurysms arising from the cavernous portion of the ICA. They were successfully treated by our
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Fig. 1. A: Left internal carotid angiogram showing a giant aneurysm in the cavernous portion of the left internal carotid artery. B: Superselective angiogram demonstrating the distal site of the aneurysmal orifice (arrow) and the ophthalmic artery (arrowheads). The distance between the origin of the ophthalmic artery and the distal site of the aneurysmal orifice is clearly seen.
strategy, which includes BTO and SPECT examination and ICA occlusion by trapping or proximal occlusion. 2. Material and methods Between 1995 and 2004, 19 patients with a giant aneurysm in the cavernous portion of the ICA were treated at our department. There were 2 males and 17 females ranging in age from 43 to 75 years (mean, 62.8 years). Their clinical presentation included mass effect with symptoms of diplopia (n = 16), retro-orbital pain (n = 1), and visual disturbance (n = 2). Diagnostic, high-magnification cerebral, and rapid-sequence digital subtraction angiograms (DSAs) were obtained to assess the aneurysmal size and shape, and the relationship of the aneurysm neck to the ICA. The aneurysms ranged from 20 to 36 mm (mean, 27.8 mm). In 13 patients, MRI revealed aneurysmal wall thrombosis. To develop a treatment strategy, 30-minute BTO was carried out. In general, a 4-vessel cerebral angiogram was obtained after complete neurologic examination to determine baseline values. A 5-Fr double-lumen occlusion balloon catheter (Celecon multi-catheter, Clinical Supply Co Ltd, Tokyo, Japan) was introduced into the femoral artery and advanced to the ICA at the level of the C2 vertebral bodies. An intravenous 5000-U bolus of heparin was injected, and the balloon was inflated until a decrease in distal ICA pressure was recorded. Upon completion of ICA
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occlusion, contrast material was injected through a 4-Fr catheter introduced into a femoral artery to confirm complete occlusion of the ICA. In 2 patients whose vasculature was highly tortuous, the balloon was introduced into the common carotid artery by direct puncture using a 5-Fr introducer. These patients underwent continuous neurologic evaluation during the first 5 minutes of BTO followed by examinations at 5-minute intervals. Balloon inflation was maintained for 30 minutes. In patients who developed neurologic deficits, the balloon was deflated immediately, and the contralateral ICA, ipsilateral ECA, and dominant vertebral artery were studied to assess the collateral circulation across the circle of Willis to detect retrograde filling of the aneurysm. Moreover, the distal pressure in the balloon catheter was continually monitored during TBO occlusion. For correct placement of the first coil, the precise distance between the ophthalmic artery and the distal site of the aneurysmal orifice must be known. Therefore, using a microcatheter, we obtained angiograms during BTO (Fig. 1). In patients who did not develop neurologic deficits in the course of 30-minute BTO, the balloon was deflated but not removed and the patient was taken to the RI suite. There it was reinflated, and CBF study was performed. Single photon emission computed tomograms using 99m TcHMPAO were obtained. After completion of the first scan within less than 10 minutes, stress was induced with an intravenous injection of 1 g acetazolamide. At 5 minutes after the second intravenous delivery of 99mTc-HMPAO, a second scan was performed; the balloon remained inflated throughout these procedures (Fig. 2). Fig. 3 shows our method of carotid artery occlusion with selective revascularization. Patients with clinical evidence of profound ischemia during BTO may require a high-flow bypass with vein grafting before ICA sacrifice. In patients without ischemic symptoms during BTO, at-rest SPECT study may demonstrate hypoperfusion of the hemisphere ipsilateral to the occlusion site. These patients may require a medium-flow bypass with radial artery grafting. Alternatively, SPECT study may demonstrate normal perfusion at rest and hypo-vasoreactivity of the hemisphere ipsilateral to the occlusion site during acetazolamide stress. These patients may require a low-flow bypass (STA-MCA bypass). Patients
Fig. 2. Time course of BTO and at-rest and acetazolamide-stressed SPECT procedures.
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Fig. 3. Management algorithm for giant cavernous sinus aneurysms in the internal carotid artery. Dx indicates diamox.
who tolerate BTO of the ICA and manifest no hypoperfusion on SPECT study at rest and during acetazolamide stress can be treated by sacrificing the ICA without a bypass. We usually sacrifice the ICA using several detachable coils. If there is retrograde filling of the aneurysm from collateral flow, we perform ICA sacrifice by trapping on both sides of the aneurysmal orifice. In the absence of retrograde filling, we sacrifice the ICA by proximal occlusion (Fig. 4). In patients who underwent ICA sacrifice and required a bypass, we first performed extracranial-intracranial bypass surgery in the operating room. Selection of the appropriate type of bypass was based on BTO- and SPECT findings. The ICA was sacrificed after bypass surgery. In patients in whom
treatment called for ICA trapping, the cervical ICA was exposed, punctured with a 3-Fr introducer, and a microcatheter (Boston Scientific, Target, Fremont, Calif) was inserted. Its tip was positioned at the distal site of the aneurysmal orifice. Portable DSA equipment was used during the procedures. After clamping the proximal site of the ICA with a Sugita aneurysmal clip, its distal site was occluded with several GDCs (GDC-18, Boston Scientific, Tokyo, Japan). Then the proximal site was occluded using 5-0 silk sutures. In patients who did not require ICA trapping, the cervical ICA was exposed and directly occluded with 5-0 Fr silk sutures. Patients who did not require bypass surgery (n = 9) underwent sacrifice of the ICA in the operating room under
Fig. 4. Management algorithm for internal carotid artery occlusion.
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3. Representative cases
aneurysm (Fig. 5B). She underwent BTO of the left cervical carotid artery without neurologic consequences. Because there was retrograde filling of the aneurysmal lumen (Fig. 5C), we concluded that trapping was necessary to treat this aneurysm. During BTO of the ICA, the at-rest SPECT scan revealed normal perfusion; vasoreactivity after acetazolamide stress was also normal (Fig. 5D and E). Therefore, she did not require anastomosis. The left cervical ICA was exposed in the operating room and punctured with a 3.0-Fr introducer using intraoperative DSA. Embolization with several GDC-18 was performed at a point just beyond the distal site of the aneurysmal orifice, and the proximal site of the left ICA at the cervical bifurcation was occluded with silk sutures. This resulted in complete trapping of the left ICA. Her postoperative course was uneventful with early, marked improvement in her previous double vision. Postoperative MRA, performed a week later, demonstrated the absence of aneurysmal filling (Fig. 5F). An MRI scan, obtained 3 weeks after the operation, showed the aneurysm to be thrombosed (Fig. 5G).
3.1. Case 1
3.2. Case 2
This 49-year-old woman, admitted 2 weeks after the onset of double vision, manifested partial paresis of the left oculomotor nerve. Magnetic resonance imaging showed a mass lesion in the left cavernous sinus (Fig. 5A); angiography showed a large left intracavernous ICA
This 51-year-old woman, admitted a month after the onset of double vision, manifested partial left oculomotor palsy. Magnetic resonance imaging disclosed a mass lesion in the left cavernous sinus (Fig. 6A); angiography showed a large left intracavernous ICA aneurysm (Fig. 6B). She
general anesthesia. When coil trapping was needed for ICA occlusion, this was achieved. The patients spent the first 24 hours after surgery in the intensive care unit under constant monitoring of their hydration status, blood pressure, and neurologic signs. During the first 48 hours, they received low-dose heparin therapy. On the second day, the oral administration of antiplatelet agents (aspirin or ticlopidine) was started; it was continued to prevent the formation of emboli from the thrombosing aneurysm. The treatment of patients manifesting ischemic complications includes therapeutic hyperperfusion and volume expansion. All patients underwent routine pre- and postoperative neuro-ophthalmologic evaluation and detailed neurologic examinations at 1 to 4 weeks after carotid artery occlusion and then at 3- to 6-month intervals (mean, 15.3 months; range, 3.4-39.4 months). Pre- and postoperative neurologic deficits were compared. All patients also underwent MRI at least 1 month after carotid artery occlusion.
Fig. 5. A: Preoperative T1-weighted magnetic resonance image demonstrating an intracavernous aneurysm. B: Preoperative left internal carotid angiogram demonstrating an intracavernous aneurysm. C: Right internal carotid angiogram demonstrating retrograde filling of the aneurysm via the anterior communicating artery. D: At-rest 99mTc-HMPAO–SPECT scan obtained during BTO. There is no laterality in the cerebral blood flow. E: 99mTc-HMPAO–SPECT scan obtained after acetazolamide administration during BTO. There is no laterality in the cerebral blood flow. F: The aneurysm is not visualized on this postoperative magnetic resonance angiogram. G: Postoperative T1-weighted magnetic resonance image demonstrating that the intracavernous aneurysm is thrombosed.
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Fig. 6. A: Preoperative T1-weighted magnetic resonance image demonstrating an intracavernous aneurysm. B: Preoperative left internal carotid angiogram demonstrating an intracavernous aneurysm. C: Left external carotid angiogram demonstrating retrograde filling of the aneurysm via the left ophthalmic artery. D: At-rest 99mTc-HMPAO–SPECT scans obtained during BTO. There is laterality in the cerebral blood flow on the left side. E: 99mTc-HMPAO–SPECT scans obtained after acetazolamide administration during BTO. The blood flow in the territory of the left middle cerebral artery is reduced. F: Postoperative left common carotid angiogram showing the arterial bypass to be widely patent. No aneurysm is visualized and the left internal carotid artery is occluded. G: Postoperative T1-weighted magnetic resonance image demonstrating that the intracavernous aneurysm is thrombosed.
underwent BTO of the left cervical carotid artery without neurologic consequences. As BTO showed retrograde filling of the aneurysmal lumen (Fig. 6C), we concluded that aneurysmal trapping was necessary in this patient. A SPECT scan obtained during BTO of the ICA disclosed hypoperfusion at rest and a severe decrease in the left compared to the right hemisphere perfusion upon acetazolamide stressing (Fig. 6D and E). These findings indicated that medium-flow bypass with radial artery grafting was required. We performed anastomosis with a radial artery graft between the cervical portion of the left ECA and the M2 portion of the left middle cerebral artery; intraoperative angiography confirmed patency of the bypass graft. The
distal site of the left ICA was occluded with a clip placed just proximal to the left ophthalmic artery bifurcation because examination of the BTO results showed the distance between the ophthalmic artery and the distal site of the aneurysmal orifice to be very short. The proximal site was occluded with silk sutures just distal to the cervical bifurcation. As a result of these procedures, the left ICA was completely trapped. Her postoperative course was uneventful with early marked improvement in her double vision. Angiography performed 1 week later demonstrated a widely patent graft without aneurysmal filling (Fig. 6F). An MRI scan obtained 2 weeks after the operation revealed a thrombosed aneurysm (Fig. 6G).
Table 1 Results of our treatment strategy to address giant aneurysms in the cavernous portion of the internal carotid artery BTO
Tolerance Tolerance Tolerance Intolerance
SPECT
At rest: normal After Dx: normal At rest: normal After Dx: poor vasoreactivity At rest: hypoperfusion After Dx: poor vasoreactivity ( )
Dx indicates diamox. a Embolism after treatment.
Bypass
Retrograde filling ( )
Retrograde filling (+)
Proximal occlusion
Trapping
( )
4
5a
STA-MCA
4
3
Radial artery graft
0
2
Vein graft
0
1
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4. Results All but 1 of the 19 patients tolerated BTO without developing any neurologic deficits. One patient experienced consciousness disturbance immediately after the start of the test; her symptoms improved after balloon deflation. Of the other patients, 2 manifested mild hypoperfusion on at-rest SPECT scans, 7 had normal perfusion on at-rest SPECT scans but manifested hypo-vasoreactivity after acetazolamide administration, and 9 demonstrated normal perfusion on at-rest SPECT scans and after acetazolamide stressing. Based on these findings 10 patients underwent bypass surgery before ICA sacrifice. One patient received a highflow bypass using a saphenous vein, 2 a medium-flow bypass using a radial artery graft, and 7 a low-flow bypass using STA-MCA anastomosis. The remaining 9 patients underwent sacrifice of the ICA only (Table 1). In 11 patients, BTO demonstrated retrograde filling of the aneurysm by collateral flow. Although we attempted ICA trapping in these cases, in 1 patient coil trapping was not possible because we were unable to pass the microcatheter through the distal orifice of the aneurysm. Therefore, this patient underwent only proximal ligation (Fig. 7A). Despite anticoagulant therapy, she had a transient ischemic complication due to an embolic episode (Fig. 7B) and underwent direct surgery. The distal site of the ICA was occluded with a clip applied between the proximal site of the ophthalmic artery and the distal orifice of the aneurysm, and the left ICA was trapped 1 day after proximal occlusion of the ICA. Her ischemic complication subsequently disappeared, and several days post-treatment her mild leftsided hemiparesis resolved. On T1-weighted MRI scans, all patients manifested posttreatment thrombosis in the aneurysmal space. At 6 months, all had a good outcome as judged by the Glasgow outcome scale, and at approximately 3 to 6 months post-treatment, all demonstrated significant improvement in their neurologic symptoms. Among the 16 patients with preoperative double vision, this symptom completely disappeared in 5, improved in 9, and was without change in 2. In 2 patients with visual disturbance and 1 with facial dysesthesia, there was a slight improvement. In the group
Fig. 7. A: Left internal carotid angiogram showing an aneurysm in the cavernous portion. B: Postoperative diffusion-weighted magnetic resonance image demonstrating multiple hyperintensity areas in the left parietal region.
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with complete postoperative resolution of their neurologic symptoms, the median interval between symptom onset and treatment was 2.2 months. This interval was 4.8 months in patients who exhibited some residual symptoms. 5. Discussion In patients with giant ICA aneurysms, neurosurgic approaches are often unsuitable and the majority of reported cases were managed by carotid ligation procedures [8]. The morbidity and mortality rate of patients whose intracranial carotid artery aneurysms were treated by ICA ligation was between 10% and 20% [23]. To reduce ischemic complications due to proximal vessel occlusion, collateral flow is provided via several types of bypass surgery [13,16,25]. It is very important to evaluate the risk of infarction from carotid occlusion before permanent ICA sacrifice. Before the introduction of BTO, approximately 25% of patients developed infarctions after, and 12% died as a result of occlusion [20]. Although the widely accepted BTO contributed to the marked decrease in the stroke rate after carotid occlusion [2,5,9,11], a significant percentage of patients with acceptable BTO results developed infarction [7,20]. Other techniques used in combination with BTO include quantitative CBF analysis (eg, SPECT with HMPAO). The addition of physiologic stressors (eg, induced hypotension, acetazolamide injection) may aid in the identification of patients with compromised cerebrovascular reserves [26,27]. Our treatment strategy of bypass selection based on BTO and SPECT results provides more exacting criteria than previously reported methods. Patients with BTO evidence of profound ischemia may require a high-flow venous bypass graft before ICA sacrifice. In some patients without ischemic symptoms during BTO, at-rest SPECT study demonstrates hypoperfusion in the hemisphere ipsilateral to the occlusion site. These patients may require a medium-flow bypass. Alternatively, in some cases, despite the absence of ischemic symptoms during BTO and the demonstration of normal atrest SPECT results, under acetazolamide stress, there is hypo-vasoreactivity of the hemisphere ipsilateral to the occlusion site. These patients may require a low-flow (STAMCA) bypass. Only patients who tolerate BTO and manifest no hypoperfusion on at-rest and acetazolamide-stressed SPECT study during ICA occlusion can be treated by sacrificing the ICA without a bypass. In our series, we encountered no patients with ischemic complications after ICA occlusion. However, 1 patient had a thromboembolic complication after proximal ligation of the ICA. In this patient, we recognized retrograde filling of the aneurysm via the collateral circulation during BTO. Although occlusion of this ICA appeared to require trapping, we were able to occlude the ICA by proximal ligation. Most intracavernous aneurysms treated by proximal occlusion thrombosed and the symptoms of cranial nerve dysfunction resolved slowly over several months. However, in some patients there was retrograde flow to the aneurysm
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from the ophthalmic artery after ICA ligation. In these cases, proximal occlusion may not produce complete thrombosis of the aneurysm and there is a risk of microemboli from the intra-aneurysmal thrombus to the distal ICA [10]. According to some studies [4,12,17,18], balloon-trapping procedures carry a decreased risk of thromboembolic complications compared with proximal balloon ligation. However, the positioning of detachable balloons is sometimes difficult, primarily because no satisfactory detachment mechanism is currently available and it remains very difficult to occlude the ICA on either side of the aneurysmal orifice with detachable balloons. Therefore, detachable coils [14,15] are superior because their precise detachment is possible [21,22]. We found that detachable coils can be placed accurately to occlude both the distal and proximal site of the orifice of aneurysms in the parent ICA and that retrograde filling completely disappeared after placing a coil just proximal to the ophthalmic artery. The correct placement of the first coil requires knowledge regarding the precise distance between the ophthalmic artery and the distal site of the aneurysmal orifice. Therefore, we obtained angiograms using a microcatheter during BTO (Fig. 1). If the distance between the ophthalmic artery and the distal site of the aneurysmal orifice is not sufficient for placement of the first coil, retrograde flow to the aneurysm may continue via the ophthalmic artery. In such cases, we avoid proximal occlusion only and attempt to include the origin of the ophthalmic artery if the vessel is supplied by collateral flow from the ECA. Ezura et al [10] emphasized that combined occlusion of the parent and ophthalmic artery is effective in giant aneurysms located between the ophthalmic and the posterior communicating artery. In another series, we will perform craniotomy and attempt to occlude the distal ICA with a clip. However, as this technique requires exposure of the ICA proximal to the bifurcation of the ophthalmic artery, these patients have to undergo skull base surgery. Of the 19 patients reported here, 16 were monitored by postocclusion follow-up lasting more than 1 year. Improvement of pre-treatment symptoms was noted in 14 (87.5%) of the 16 patients. Double vision persisted in 11 patients (57.9%), although in 9 this symptom was milder and 2 reported no change. Posttreatment, 5 patients were completely asymptomatic with normal neurologic examinations. As the median interval between symptom onset and treatment was shorter in the group with complete symptom resolution, we conclude that early treatment is important in patients with giant aneurysms in the cavernous portion of the ICA. We suggest that treatment should be delivered within 3 months of symptom onset. 6. Conclusion In patients with giant aneurysms in the cavernous portion of the ICA, BTO and SPECT results must be carefully analyzed before ICA occlusion. We found that ICA trapping
or proximal occlusion combined with bypass surgery was an effective treatment strategy. References [1] Al-Rodhan NR, Piepgras DG, Sundt Jr TM. Transitional cavernous aneurysms of the internal carotid artery. Neurosurgery 1993;33:993 - 6. [2] Barnett DW, Barrow DL, Joseph GJ. Combined extracranialintracranial bypass and intraoperative balloon occlusion for the treatment of intracavernous and proximal carotid artery aneurysms. Neurosurgery 1994;35:92 - 7. [3] Bavinzski G, Killer M, Ferraz-Leite H, Gruber A, Gross CE, Richling B. Endovascular therapy of idiopathic cavernous aneurysms over 11 years. AJNR Am J Neuroradiol 1998;19:559 - 65. [4] Berenstein A, Ransohoff J, Kupersmith M, Flamm E, Graeb D. Transvascular treatment of giant aneurysms of the cavernous carotid and vertebral arteries. Functional investigation and embolization. Surg Neurol 1984;21:3 - 12. [5] Date I, Ohmoto T. Long-term outcome of surgical treatment of intracavernous giant aneurysms. Neurol Med Chir (Tokyo) 1998; 38(Suppl):62 - 9. [6] Debrun G, Fox A, Drake C, Peerless S, Girvin J, Ferguson G. Giant unclippable aneurysms: treatment with detachable balloons. AJNR Am J Neuroradiol 1981;2:167 - 73. [7] Diaz FG, Ausman JI, Pearce JE. Ischemic complications after combined internal carotid artery occlusion and extracranial-intracranial anastomosis. Neurosurgery 1982;10:563 - 70. [8] Drake CG, Peerless SJ, Ferguson GG. Hunterian proximal arterial occlusion for giant aneurysms of the carotid circulation. J Neurosurg 1994;81:656 - 65. [9] Erba SM, Horton JA, Latchaw RE, Yonas H, Sekhar L, Schramm V, Pentheny S. Balloon test occlusion of the internal carotid artery with stable xenon/CT cerebral blood flow imaging. AJNR Am J Neuroradiol 1988;9:533 - 8. [10] Ezura M, Takahashi A, Yoshimoto T. Combined intravascular parent artery and ophthalmic artery occlusion for giant aneurysms of the supraclinoid internal carotid artery. Surg Neurol 1997;47:360 - 3. [11] Field M, Jungreis CA, Chengelis N, Kromer H, Kirby L, Yonas H. Symptomatic cavernous sinus aneurysms: management and outcome after carotid occlusion and selective cerebral revascularization. AJNR Am J Neuroradiol 2003;24:1200 - 7. [12] Fox AJ, Vinuela F, Pelz DM, Peerless SJ, Ferguson GG, Drake CG, Debrun G. Use of detachable balloons for proximal artery occlusion in the treatment of unclippable cerebral aneurysms. J Neurosurg 1987;66:40 - 6. [13] Gelber BR, Sundt Jr TM. Treatment of intracavernous and giant carotid aneurysms by combined internal carotid ligation and extra- to intracranial bypass. J Neurosurg 1980;52:1 - 10. [14] Guglielmi G, Vinuela F, Dion J, Duckwiler G. Electrothrombosis of saccular aneurysms via endovascular approach: Part 2. Preliminary clinical experience. J Neurosurg 1991;75:8 - 14. [15] 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. [16] Heros RC, Nelson PB, Ojemann RG, Crowell RM, DeBrun G. Large and giant paraclinoid aneurysms: surgical techniques, complications, and results. Neurosurgery 1983;12:153 - 63. [17] Higashida RT, Halbach VV, Barnwell SL, Dowd C, Dormandy B, Bell GB, Hieshima GB. Treatment of intracranial aneurysms with preservation of the parent vessel: results of percutaneous balloon embolization in 84 patients. AJNR Am J Neuroradiol 1990;11:633 - 40. [18] Higashida RT, Halbach VV, Dowd C, Barnwell SL, Dormandy B, Bell J, Hieshima GB. Endovascular detachable balloon embolization therapy of cavernous carotid artery aneurysms: results in 87 cases. J Neurosurg 1990;72:857 - 63.
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Commentary The authors outline a management algorithm for giant cavernous carotid aneurysms, using information from BTO augmented with SPECT with and without diamox to stratify their treatment strategy. Although there have been proponents of universal revascularization in the setting of carotid occlusion for aneurysms [3], such a nonselective approach imposes the potential for unnecessary morbidity. A selective approach that can accurately identify those patients who are in true need of revascularization and also guide the appropriate revascularization strategy represents the optimal strategy. In this paper, the authors propose just such a selective approach, stratifying patients based upon results of BTO combined with SPECT and diamox challenge. Based upon the severity of hypoperfusion, they perform either vein, radial artery, or STA bypass, reflecting the need for bhigh flow,Q bmedium flow,Q or blow flow.Q In addition, the authors advocate trapping of the aneurysm over proximal occlusion if retrograde filling of the aneurysm is angiographically evident.
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In our own institution, we also adopt a similar strategy, but using BTO with hypotensive challenge and SPECT, rather than diamox. In addition, we feel that, although the severity of hypoperfusion with BTO can guide the operative plan as to the type of bypass required, the decision regarding the appropriate conduit, and confirmation of adequate flow replacement, should be performed intra-operatively. Our standard practice at the time of surgery in such cases is to perform direct intraoperative measurement of the middle cerebral artery flow during surgery using an ultrasonic flow probe [2]. Reduction in flow is then directly measured during temporary clamping of the proximal ICA. The measured flow deficit is used as the final determinant to choose the appropriate conduit for the bypass. Furthermore, the direct flow measurements provide in situ confirmation of the accuracy of the preoperative BTO protocol. In addition, although vein grafts are typically considered to be bhigh flow,Q even an STA branch may be adequate if the actual flow deficit is known, and the STA flow-carrying capacity (measurable as the free flow from its cut end [1]) is sufficient. As such, we are able to designate the bypass as high, medium, or low flow based upon in situ flow measurement rather than the assumed flow assigned to particular types of bypass conduits. Regarding the authors’ strict requirement for trapping of an aneurysm if retrograde filling is observed, we have generally felt that proximal occlusion is often adequate in such cases as the aneurysm will progress to full thrombosis. Their experience with one patient in the series who had thromboembolism under those circumstances does emphasize the need for careful attention to both antiplatelet and anticoagulant therapy. If trapping is pursued, distal clip occlusion may be preferable to distal coil occlusion from the standpoint of thromboembolic risk, especially in the cases where surgery is already being performed for the purpose of bypass; clip occlusion is generally safe and effective even above the level of the ophthalmic origin, avoiding the need for additional dissection and clinoidectomy. Sepideh Amin-Hanjani, MD Fady T. Charbel, MD Department of Neurosurgery University of Illinois at Chicago Chicago, IL 60612, USA References [1] Amin-Hanjani S, Du X, Mlinarevich N, Meglio G, Zhao M, Charbel FT. The cut flow index: an intraoperative predictor of the success of extracranial-intracranial bypass for occlusive cerebrovascular disease. Neurosurgery 2005;56:75 - 85. [2] Charbel FT, Hoffman WE, Misra M, Ostergren L. Ultrasonic perivascular flow probe: technique and application in neurosurgery. Neurol Res 1998;20:439 - 42. [3] Lawton MT, Hamilton MG, Morcos JJ, Spetzler RF. Revascularization and aneurysm surgery: current techniques, indications, and outcome. Neurosurgery 1996;38:83 - 92 [discussion 92-84].