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Surgical treatment of giant internal carotid artery aneurysms
International Congress Series 1247 (2002) 75 – 84
Surgical treatment of giant internal carotid artery aneurysms Kazuo Mizoi a,*, Hiroyuki Kinouchi a, Akira Takahashi b, Takashi Yoshimoto b b
a Department of Neurosurgery, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan Department of Neurosurgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, 980-8574, Sendai, Japan
Abstract Objective: Surgery for giant internal carotid artery (ICA) aneurysms has been performed relatively safely with the advancement of microneurosurgical techniques. However, it is also the fact that the degree of surgical difficulty greatly differs by its case, while the aneurysm shows similar angiographic picture. The present study analyzes variation and selection of the clipping method for giant ICA aneurysms. Methods: We analyzed the clipping methods in 25 patients with giant paraclinoid ICA aneurysms which arise from the ophthalmic segment between the distal dural ring and the origin of the PcomA. Five aneurysms were anterior paraclinoid type (so-called ophthalmic aneurysm) and 20 aneurysms were posterior paraclinoid type (so-called ventral paraclinoid aneurysm). All patients underwent surgery with the use of retrograde suction decompression method and intraoperative angiography. Results: Clipping method for the anterior paraclinoid aneurysm was relatively simple, and it was obliterated with the use of straight or angled clips. Although multiple clipping method using fenestrated angled clips was tried for posterior paraclinoid aneurysms, this method was possible in 17 of the 20 cases. In remaining three cases, the ICA had greatly shifted laterally, and it was difficult to get sufficient working space for clip application. In these cases, the aneurysm neck was narrowed with a ligature and then large straight clips were applied perpendicularly to the ICA. Conclusion: The incidence of posterior paraclinoid aneurysm is high, and its operation is more difficult. It is important to trace the course of the ICA in the AP view angiogram, especially the degree of inclination of the ICA, for the preoperative planning of clipping method. Although parallel clip application is more reasonable to reconstruct the ICA, perpendicular clipping is suitable especially when the ICA is displaced far laterally. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Carotid artery; Aneurysm; Surgery
*
Corresponding author. Tel.: +81-18-884-6136; fax: +81-18-836-2616. E-mail address: [email protected] (K. Mizoi).
0531-5131/02 D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 5 3 1 - 5 1 3 1 ( 0 2 ) 0 1 0 4 0 - 3
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1. Introduction With current advances in microsurgical techniques, the surgical treatment of cerebral aneurysms is now approaching satisfactory level. However, technical difficulties in aneurysm surgery are determined by two main factors; the size and the location of aneurysms. Many problems still remain for surgery on the large aneurysms of the proximal internal carotid artery (ICA), because in the surgery for such aneurysms there is considerable difficulty in gaining both proximal arterial control and sufficient operative field. Since 1986, with the introduction of digital subtraction angiography (DSA) apparatus to our operating room, we have attempted to operate upon the surgically difficult aneurysms with the aid of intravascular catheter techniques [6,7]. Such techniques can be summarized as follows: (1) A balloon catheter is placed into the parent artery of the aneurysm to obtain temporary proximal occlusion. (2) A double lumen balloon catheter is used for large aneurysms to aspirate blood and collapse the aneurysm. (3) The result of aneurysm clipping is evaluated using intraoperative DSA. In this paper, we review our experiences with the combined use of intravascular and neurosurgical approaches in giant ICA aneurysms, including variation and selection of clipping techniques.
2. Patient population From January, 1986, to July, 2000, a total of 25 large or giant paraclinoid ICA aneurysms in 24 patients were operated on with the aid of endovascular catheter techniques. The size of aneurysms ranged from 14 to 26 mm in diameter, with an average size of 20 mm. Those aneurysms were further subdivided by location and direction of aneurysmal growth: five anterior paraclinoid aneurysm (so-called ophthalmic aneurysms) and posterior paraclinoid aneurysms (so-called ventral paraclinoid aneurysms). All 24 patients were female, ranging in age from 33 to 71 years (mean 57 years). Six patients presented with subarachnoid hemorrhage, 16 patients presented with monocular visual disturbance, and the remaining 2 patients had incidental aneurysms.
3. Introduction of balloon catheter The patient was placed on a radiolucent operating table. After the induction of anesthesia, the head was fixed in the desired position with a radiolucent carbon head holder (Fig. 1). The No. 5 or 7 French double lumen occlusion balloon catheter was introduced coaxially through the femoral sheath to the cervical ICA under fluoroscopic control. The balloon was inflated tentatively to assess the appropriate inflation volume to occlude the ICA. Both the femoral sheath and the double lumen balloon catheter were flushed continually at 0.5 ml/min with heparinized saline (10 U/ml). The femoral sheath could be used as the arterial line for systemic blood pressure monitoring. The groin was sterilely
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Fig. 1. The patient’s head is fixed with a radiolucent carbon-composite head holder. The electrodes for evoked potential monitoring were also placed.
draped and covered for the subsequent intraoperative catheterization procedures, and the craniotomy begun.
4. Surgical procedures and retrograde suction decompression technique Extensive removal of anterior clinoid process was essential in the surgery for large paraclinoid ICA aneurysms or carotid cave aneurysms. We usually use the Dolenc’s combined epi- and intradural approach [2]. From a point when the operation proceeded until the stage of the dissection of aneurysm, the balloon was inflated. After temporary trapping of the aneurysm by balloon occlusion of the cervical ICA and clipping of the intracranial ICA distal to the aneurysm, retrograde aspiration of blood was initiated manually using the 20 ml heparinized syringe (Fig. 2). By means of this procedure, the aneurysm was completely deflated and the dissection of the aneurysm was greatly facilitated. It is most important to preserve the patency of anterior choroidal artery and clip the aneurysm while preserving the sufficient lumen of the ICA. As for the cerebral
Fig. 2. Schematic drawing showing the retrograde balloon suction decompression technique. The double lumen balloon catheter was placed inside the cervical ICA through a transfemoral route.
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Fig. 3. The operating room set-up during intraoperative angiography. The operating microscope was displaced, and the sterilely draped C-arm fluoroscope was positioned around the patient’s head.
protection during temporary occlusion, we administered the solution of 500 ml of 20% mannitol with 500 mg of phenytoin and 500 mg of vitamin E [11,12]. In all of our cases, we confirmed the results of the clipping using intraoperative DSA (Fig. 3), and if the results were unsatisfactory, the clipping was adjusted. The catheter was removed after final examination of intraoperative DSA, but the femoral sheath was left in place until the end of operation.
5. Case report 5.1. Case report 1 This 50-year-old woman presented with progressive loss of vision in the left eye. A computed tomography (CT) scan revealed a round mass lesion on the left suprasellar region. Angiography demonstrated a large paraclinoid ICA aneurysm 26 mm in diameter (Fig. 4).
Fig. 4. Case 1. Preoperative angiogram of the left ICA, demonstrating a giant paraclinoid aneurysm. (A) AP view, (B) lateral view.
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Fig. 5. Case 1. (A) Operative photographs of a giant paraclinoid aneurysm compressing the left optic nerve. (B) The aneurysm was deflated and easily dissected with the aid of retrograde continuous blood aspiration. (C) Two Sugita fenestrated clips were applied in crosswise fashion to reconstruct sufficient lumen of the internal carotid artery.
Surgery was performed using the retrograde balloon suction decompression method. Under general anesthesia, the double lumen balloon catheter was introduced to the left ICA by the transfemoral route. After confirming the sufficient inflation volume of the balloon, left pterional craniotomy was performed. The anterior clinoid process was removed extradurally and the optic canal was unroofed. Since this large aneurysm had projected posteriorly and expanded close to the carotid dural ring, the proximal dome of the aneurysm was tightly adherent to the surrounding dura mater (Fig. 5A). At this point, the balloon was inflated to occlude the cervical ICA. The intracranial ICA (C1 segment) was also occluded, and retrograde suctioning begun. The aneurysm collapsed completely and easily dissected (Fig. 5B). The anterior choroidal artery was recognized on the distal side of the aneurysm neck. Two Sugita fenestrated clips were applied in crosswise fashion to reconstruct sufficient lumen of the ICA (Fig. 5C). The duration of temporary trapping of ICA was 20 min. About 200 ml of blood was aspirated during this procedure and returned to the patient simultaneously. The operation
Fig. 6. Case 1. (A) Intraoperative angiogram before clip placement, demonstrating a giant paraclinoid aneurysm. (B) Intraoperative angiogram after aneurysmal clipping, showing successful result.
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Fig. 7. Case 2. Preoperative angiogram of the left internal carotid artery, demonstrating a giant paraclinoid aneurysm and lateral inclination of the right ICA. (A) AP view, (B) lateral view.
was completed after confirming the result of clip placement by DSA (Fig. 6). The patient awoke from anesthesia with no new neurological deficits. Three months later, she had full recovery of visual disturbance in the left eye. 5.2. Case report 2 This 57-year-old female presented with the visual disturbance in the right eye. Angiography demonstrated a large paraclinoid aneurysm 28 mm in diameter and lateral inclination of the ICA (Fig. 7).
Fig. 8. Case 2. (A) Operative photographs of a giant paraclinoid aneurysm compressing the right optic nerve. (B) The aneurysm sac was deflated completely with the aid of retrograde blood aspiration. (C) At first, the angled fenestrated clip was used to clip the aneurysm. However, it was very difficult to apply the clip in parallel to the course of the internal carotid artery because of the limited working space. Then, the aneurysm neck was ligated to reduce the size of the neck. (D) Finally, perpendicular clipping was performed using a strong straight clip.
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Fig. 9. Case 2. Intraoperative angiogram after aneurysmal clipping, showing successful result. (A) AP view, (B) lateral view.
Surgery was performed using the same method as described in Case 1. Using retrograde suction decompression, the aneurysm was collapsed remarkably, and dissected free from the surrounding structures. Several attempts were made to clip this aneurysm with parallel clipping method using the fenestrated clips. However, severe kinking of the ICA occurred on all such occasions. Finally, the aneurysmal neck was ligated to narrow the size of the neck, and perpendicular clipping was attempted using strong straight clips (Fig. 8). Booster clip was applied on the distal end of the first clip blades for reinforcement. The intraoperative angiogram showed a good result of clipping (Fig. 9). The postoperative course was uneventful.
6. Results 6.1. Clipping methods Clipping method for the anterior paraclinoid aneurysm was relatively simple. Clip application was performed in parallel with the ICA with the use of straight or angled clips. Although multiple clipping method using fenestrated angled clips was tried for posterior paraclinoid aneurysms, this method was possible in only 17 of the 20 cases. In remaining three cases, the ICA had greatly shifted laterally, and it was difficult to get sufficient working space for clip application. In these cases, the aneurysm neck was narrowed with a ligature and then large straight clips were applied perpendicularly to the ICA. 6.2. Temporary occlusion The duration of temporary occlusion among these 25 aneurysms ranged from 6 to 60 min, with a mean of 20.5 min. Intraoperative somatosensory evoked potential (SEP) monitoring was also performed in all cases. Significant changes in the SEP were not observed during the occlusion in any case [5]. However, only one case demonstrated
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Fig. 10. Continuous monitoring of the carotid stump pressure during the balloon suction decompression. On inflating the balloon within the cervical internal carotid artery (arrow), the stump pressure decreased to about 30% of the pre-occlusion level; but subsequent occlusion of the intracranial carotid artery distal to the aneurysm (arrowhead) caused a paradoxical increase in stump pressure. SAP: systemic arterial pressure.
postoperative sequelae attributable to the ischemia of the territory of the anterior cerebral artery, which could not be monitored by the median nerve SEP. 6.3. Paradoxical rise of stump pressure during aneurysm trapping The carotid stump pressure was monitored through the distal lumen of the double lumen balloon catheter placed in the cervical ICA. On inflating the balloon, the stump pressure fell to about 50%; however, contrary to expectations, following occlusion of the intracranial ICA above the aneurysm, the pressure increased to a level above the preocclusion level (Fig. 10). Operative findings also indicated that the aneurysm became tenser. However, on beginning retrograde aspiration, the aneurysm collapsed completely. The rate of blood aspiration was between 10 and 20 ml/min. When the syringe was exchanged and the aspiration temporarily interrupted, the aneurysm again became inflated. The aspirated blood was returned to the patient intravenously. The total volume of aspirated blood differed among the patients, but was between 200 and 500 ml.
7. Discussion 7.1. Retrograde suction decompression technique Flamm [3] was the first to report on a suction decompression method for giant aneurysms, in which the aneurysm was directly punctured using a No. 21 scalp vein needle. In puncturing the aneurysmal wall before treatment of the aneurysm, however, that technique may invite troublesome intraoperative bleeding. Subsequently, Batjer and Samson [1] and Tamaki et al. [13] reported retrograde suction methods in which the cervical ICA is exposed surgically and blood is aspirated from an angiocatheter inserted to the cervical ICA after clamping of both the cervical and intracranial ICA. Scott et al.
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reported a less invasive modification of that method in which retrograde suction was done using a double lumen balloon catheter [8]. They also reported on their experience with the treatment of supraclinoid carotid aneurysms using balloon suction decompression in 12 patients, and described one complication of monocular blindness [9]. Balloon suction decompression technique is extremely effective for dissection of paraclinoid large aneurysms. However, even when the aneurysm is completely deflated, basic surgical procedures for treatment of aneurysms in this location, such as extensive removal of the anterior clinoid process and sufficient exposure of the carotid dural ring, are still essential. With the experience of this method, we found an interesting phenomenon. That is, while monitoring the carotid stump pressure by means of a double lumen balloon catheter placed in the cervical ICA, inflation of the balloon (proximal occlusion) resulted in a sudden decrease in stump pressure to about 50% of the pre-occlusion level; but subsequent occlusion of the intracranial ICA (distal occlusion) resulted in an increase in stump pressure to a level above the pre-occlusion level. This finding indicates that when an aneurysm is incompletely trapped, intra-aneurysmal pressure can be elevated by the retrograde flow through the small remaining branches. Even in cases where the ophthalmic artery, PcomA and anterior choroidal artery have been occluded, similar increases in stump pressure are observed, suggesting the notable participation of retrograde flow from the cavernous ICA branches involving meningohypophyseal trunk. To our knowledge, this paradoxical phenomenon has not been reported previously. However, as Batjer and Samson [1] pointed out, many neurosurgeons may empirically be aware of this phenomenon through their experience that simple trapping of the large aneurysm by cervical ICA clamping and intracranial distal clipping does not adequately soften the lesion because of a brisk retrograde flow through the ophthalmic artery and cavernous branches. This phenomenon also implies that a risk of aneurysmal rupture may increase following such a simple trapping as a result of paradoxical rise in the intra-aneurysmal pressure. There have been several case reports of patients who died due to the fatal rupture of a previously unruptured giant aneurysm after an extracranial – intracranial bypass with proximal carotid artery ligation had been performed [4,10]. It is possible that the cause of rupture in those cases is a hemodynamic change similar to that seen in simple trapping. Thus far, we have used this suction decompression method only in cases of ICA aneurysms, but the indication for its use may theoretically expand with advances in technology to include giant posterior circulation aneurysms. 7.2. Clipping technique Clipping technique for anterior paraclinoid aneurysm was relatively simple, but operation of posterior paraclinoid aneurysm is more difficult. In all 20 cases with posterior paraclinoid aneurysms, we tried to use the tandem clipping method using fenestrated angled clips. However, this method was only possible in 17 cases. In remaining three cases, the ICA had greatly shifted laterally, then fenestrated clipping resulted in severe kinking of the ICA. In these cases, the aneurysm neck was narrowed with a ligature and then large straight clips were applied perpendicularly to the ICA. From our experience, the direction of the ICA is the important factor influencing surgical difficulty. It is important to
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trace the course of the ICA in the AP view angiogram, especially the degree of inclination of the ICA, for the preoperative planning of clipping method. Although parallel clip application is more reasonable to reconstruct the ICA, perpendicular clipping is the alternative option, especially when the ICA is displaced far laterally. Even if the aneurysm is giant size, with complete aneurysm deflation, the conventional technique of neck ligation and clipping technique does not result in significant stenosis of the parent artery.
References [1] H.H. Batjer, D.S. Samson, Retrograde suction decompression of giant paraclinoidal aneurysms. Technical note, J. Neurosurg. 73 (1990) 305 – 306. [2] V.V. Dolenc, A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms, J. Neurosurg. 62 (1985) 667 – 672. [3] E.S. Flamm, Suction decompression of aneurysms. Technical note, J. Neurosurg. 54 (1981) 275 – 276. [4] M. Matsuda, A. Shiino, J. Handa, Rupture of previously unruptured giant carotid aneurysm after superficial temporal-middle cerebral artery bypass and internal carotid occlusion, Neurosurgery 16 (1985) 177 – 184. [5] K. Mizoi, T. Yoshimoto, Permissible temporary occlusion time in aneurysm surgery as evaluated by evoked potential monitoring, Neurosurgery 33 (1993) 434 – 440. [6] K. Mizoi, A. Takahashi, T. Yoshimoto, et al., Combined intravascular and neurosurgical approach for paraclinoid internal carotid artery aneurysms, Neurosurgery 33 (1993) 986 – 992. [7] K. Mizoi, T. Yoshimoto, A. Takahashi, et al., Direct clipping of basilar trunk aneurysms using balloon temporary occlusion, J. Neurosurg. 80 (1994) 230 – 236. [8] J.A. Scott, T.G. Horner, T.J. Leipzig, Retrograde suction decompression of an ophthalmic artery aneurysm using balloon occlusion. Technical note, J. Neurosurg. 75 (1991) 146 – 147. [9] J.A. Scott, Occlusion balloon suction decompression of supraclinoid carotid aneurysms: work in progress, Neuroradiology 33 (1991) S146 (Suppl.). [10] R.M. Scott, H.C. Liu, R. Yuan, et al., Rupture of a previously unruptured giant middle cerebral artery aneurysm after extracranial – intracranial bypass surgery, Neurosurgery 10 (1982) 600 – 603. [11] J. Suzuki, S. Fujimoto, K. Mizoi, et al., The protective effect of combined administration of antioxidants and perfluorochemicals on cerebral ischemia, Stroke 15 (1984) 672 – 679. [12] J. Suzuki, H. Abiko, K. Mizoi, et al., Protective effect of phenytoin and its enhanced action by combined administration with mannitol and vitamin E in cerebral ischemia, Acta Neurochir. (Wien) 88 (1987) 56 – 64. [13] N. Tamaki, S. Kim, K. Ehara, et al., Giant carotid-ophthalmic artery aneurysms: direct clipping utilizing the ‘‘trapping-evacuation’’ technique, J. Neurosurg. 74 (1991) 567 – 572.
Surgical treatment of giant internal carotid artery aneurysms Kazuo Mizoi a,*, Hiroyuki Kinouchi a, Akira Takahashi b, Takashi Yoshimoto b b
a Department of Neurosurgery, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan Department of Neurosurgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, 980-8574, Sendai, Japan
Abstract Objective: Surgery for giant internal carotid artery (ICA) aneurysms has been performed relatively safely with the advancement of microneurosurgical techniques. However, it is also the fact that the degree of surgical difficulty greatly differs by its case, while the aneurysm shows similar angiographic picture. The present study analyzes variation and selection of the clipping method for giant ICA aneurysms. Methods: We analyzed the clipping methods in 25 patients with giant paraclinoid ICA aneurysms which arise from the ophthalmic segment between the distal dural ring and the origin of the PcomA. Five aneurysms were anterior paraclinoid type (so-called ophthalmic aneurysm) and 20 aneurysms were posterior paraclinoid type (so-called ventral paraclinoid aneurysm). All patients underwent surgery with the use of retrograde suction decompression method and intraoperative angiography. Results: Clipping method for the anterior paraclinoid aneurysm was relatively simple, and it was obliterated with the use of straight or angled clips. Although multiple clipping method using fenestrated angled clips was tried for posterior paraclinoid aneurysms, this method was possible in 17 of the 20 cases. In remaining three cases, the ICA had greatly shifted laterally, and it was difficult to get sufficient working space for clip application. In these cases, the aneurysm neck was narrowed with a ligature and then large straight clips were applied perpendicularly to the ICA. Conclusion: The incidence of posterior paraclinoid aneurysm is high, and its operation is more difficult. It is important to trace the course of the ICA in the AP view angiogram, especially the degree of inclination of the ICA, for the preoperative planning of clipping method. Although parallel clip application is more reasonable to reconstruct the ICA, perpendicular clipping is suitable especially when the ICA is displaced far laterally. D 2002 Elsevier Science B.V. All rights reserved. Keywords: Carotid artery; Aneurysm; Surgery
*
Corresponding author. Tel.: +81-18-884-6136; fax: +81-18-836-2616. E-mail address: [email protected] (K. Mizoi).
0531-5131/02 D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 5 3 1 - 5 1 3 1 ( 0 2 ) 0 1 0 4 0 - 3
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1. Introduction With current advances in microsurgical techniques, the surgical treatment of cerebral aneurysms is now approaching satisfactory level. However, technical difficulties in aneurysm surgery are determined by two main factors; the size and the location of aneurysms. Many problems still remain for surgery on the large aneurysms of the proximal internal carotid artery (ICA), because in the surgery for such aneurysms there is considerable difficulty in gaining both proximal arterial control and sufficient operative field. Since 1986, with the introduction of digital subtraction angiography (DSA) apparatus to our operating room, we have attempted to operate upon the surgically difficult aneurysms with the aid of intravascular catheter techniques [6,7]. Such techniques can be summarized as follows: (1) A balloon catheter is placed into the parent artery of the aneurysm to obtain temporary proximal occlusion. (2) A double lumen balloon catheter is used for large aneurysms to aspirate blood and collapse the aneurysm. (3) The result of aneurysm clipping is evaluated using intraoperative DSA. In this paper, we review our experiences with the combined use of intravascular and neurosurgical approaches in giant ICA aneurysms, including variation and selection of clipping techniques.
2. Patient population From January, 1986, to July, 2000, a total of 25 large or giant paraclinoid ICA aneurysms in 24 patients were operated on with the aid of endovascular catheter techniques. The size of aneurysms ranged from 14 to 26 mm in diameter, with an average size of 20 mm. Those aneurysms were further subdivided by location and direction of aneurysmal growth: five anterior paraclinoid aneurysm (so-called ophthalmic aneurysms) and posterior paraclinoid aneurysms (so-called ventral paraclinoid aneurysms). All 24 patients were female, ranging in age from 33 to 71 years (mean 57 years). Six patients presented with subarachnoid hemorrhage, 16 patients presented with monocular visual disturbance, and the remaining 2 patients had incidental aneurysms.
3. Introduction of balloon catheter The patient was placed on a radiolucent operating table. After the induction of anesthesia, the head was fixed in the desired position with a radiolucent carbon head holder (Fig. 1). The No. 5 or 7 French double lumen occlusion balloon catheter was introduced coaxially through the femoral sheath to the cervical ICA under fluoroscopic control. The balloon was inflated tentatively to assess the appropriate inflation volume to occlude the ICA. Both the femoral sheath and the double lumen balloon catheter were flushed continually at 0.5 ml/min with heparinized saline (10 U/ml). The femoral sheath could be used as the arterial line for systemic blood pressure monitoring. The groin was sterilely
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Fig. 1. The patient’s head is fixed with a radiolucent carbon-composite head holder. The electrodes for evoked potential monitoring were also placed.
draped and covered for the subsequent intraoperative catheterization procedures, and the craniotomy begun.
4. Surgical procedures and retrograde suction decompression technique Extensive removal of anterior clinoid process was essential in the surgery for large paraclinoid ICA aneurysms or carotid cave aneurysms. We usually use the Dolenc’s combined epi- and intradural approach [2]. From a point when the operation proceeded until the stage of the dissection of aneurysm, the balloon was inflated. After temporary trapping of the aneurysm by balloon occlusion of the cervical ICA and clipping of the intracranial ICA distal to the aneurysm, retrograde aspiration of blood was initiated manually using the 20 ml heparinized syringe (Fig. 2). By means of this procedure, the aneurysm was completely deflated and the dissection of the aneurysm was greatly facilitated. It is most important to preserve the patency of anterior choroidal artery and clip the aneurysm while preserving the sufficient lumen of the ICA. As for the cerebral
Fig. 2. Schematic drawing showing the retrograde balloon suction decompression technique. The double lumen balloon catheter was placed inside the cervical ICA through a transfemoral route.
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Fig. 3. The operating room set-up during intraoperative angiography. The operating microscope was displaced, and the sterilely draped C-arm fluoroscope was positioned around the patient’s head.
protection during temporary occlusion, we administered the solution of 500 ml of 20% mannitol with 500 mg of phenytoin and 500 mg of vitamin E [11,12]. In all of our cases, we confirmed the results of the clipping using intraoperative DSA (Fig. 3), and if the results were unsatisfactory, the clipping was adjusted. The catheter was removed after final examination of intraoperative DSA, but the femoral sheath was left in place until the end of operation.
5. Case report 5.1. Case report 1 This 50-year-old woman presented with progressive loss of vision in the left eye. A computed tomography (CT) scan revealed a round mass lesion on the left suprasellar region. Angiography demonstrated a large paraclinoid ICA aneurysm 26 mm in diameter (Fig. 4).
Fig. 4. Case 1. Preoperative angiogram of the left ICA, demonstrating a giant paraclinoid aneurysm. (A) AP view, (B) lateral view.
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Fig. 5. Case 1. (A) Operative photographs of a giant paraclinoid aneurysm compressing the left optic nerve. (B) The aneurysm was deflated and easily dissected with the aid of retrograde continuous blood aspiration. (C) Two Sugita fenestrated clips were applied in crosswise fashion to reconstruct sufficient lumen of the internal carotid artery.
Surgery was performed using the retrograde balloon suction decompression method. Under general anesthesia, the double lumen balloon catheter was introduced to the left ICA by the transfemoral route. After confirming the sufficient inflation volume of the balloon, left pterional craniotomy was performed. The anterior clinoid process was removed extradurally and the optic canal was unroofed. Since this large aneurysm had projected posteriorly and expanded close to the carotid dural ring, the proximal dome of the aneurysm was tightly adherent to the surrounding dura mater (Fig. 5A). At this point, the balloon was inflated to occlude the cervical ICA. The intracranial ICA (C1 segment) was also occluded, and retrograde suctioning begun. The aneurysm collapsed completely and easily dissected (Fig. 5B). The anterior choroidal artery was recognized on the distal side of the aneurysm neck. Two Sugita fenestrated clips were applied in crosswise fashion to reconstruct sufficient lumen of the ICA (Fig. 5C). The duration of temporary trapping of ICA was 20 min. About 200 ml of blood was aspirated during this procedure and returned to the patient simultaneously. The operation
Fig. 6. Case 1. (A) Intraoperative angiogram before clip placement, demonstrating a giant paraclinoid aneurysm. (B) Intraoperative angiogram after aneurysmal clipping, showing successful result.
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Fig. 7. Case 2. Preoperative angiogram of the left internal carotid artery, demonstrating a giant paraclinoid aneurysm and lateral inclination of the right ICA. (A) AP view, (B) lateral view.
was completed after confirming the result of clip placement by DSA (Fig. 6). The patient awoke from anesthesia with no new neurological deficits. Three months later, she had full recovery of visual disturbance in the left eye. 5.2. Case report 2 This 57-year-old female presented with the visual disturbance in the right eye. Angiography demonstrated a large paraclinoid aneurysm 28 mm in diameter and lateral inclination of the ICA (Fig. 7).
Fig. 8. Case 2. (A) Operative photographs of a giant paraclinoid aneurysm compressing the right optic nerve. (B) The aneurysm sac was deflated completely with the aid of retrograde blood aspiration. (C) At first, the angled fenestrated clip was used to clip the aneurysm. However, it was very difficult to apply the clip in parallel to the course of the internal carotid artery because of the limited working space. Then, the aneurysm neck was ligated to reduce the size of the neck. (D) Finally, perpendicular clipping was performed using a strong straight clip.
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Fig. 9. Case 2. Intraoperative angiogram after aneurysmal clipping, showing successful result. (A) AP view, (B) lateral view.
Surgery was performed using the same method as described in Case 1. Using retrograde suction decompression, the aneurysm was collapsed remarkably, and dissected free from the surrounding structures. Several attempts were made to clip this aneurysm with parallel clipping method using the fenestrated clips. However, severe kinking of the ICA occurred on all such occasions. Finally, the aneurysmal neck was ligated to narrow the size of the neck, and perpendicular clipping was attempted using strong straight clips (Fig. 8). Booster clip was applied on the distal end of the first clip blades for reinforcement. The intraoperative angiogram showed a good result of clipping (Fig. 9). The postoperative course was uneventful.
6. Results 6.1. Clipping methods Clipping method for the anterior paraclinoid aneurysm was relatively simple. Clip application was performed in parallel with the ICA with the use of straight or angled clips. Although multiple clipping method using fenestrated angled clips was tried for posterior paraclinoid aneurysms, this method was possible in only 17 of the 20 cases. In remaining three cases, the ICA had greatly shifted laterally, and it was difficult to get sufficient working space for clip application. In these cases, the aneurysm neck was narrowed with a ligature and then large straight clips were applied perpendicularly to the ICA. 6.2. Temporary occlusion The duration of temporary occlusion among these 25 aneurysms ranged from 6 to 60 min, with a mean of 20.5 min. Intraoperative somatosensory evoked potential (SEP) monitoring was also performed in all cases. Significant changes in the SEP were not observed during the occlusion in any case [5]. However, only one case demonstrated
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Fig. 10. Continuous monitoring of the carotid stump pressure during the balloon suction decompression. On inflating the balloon within the cervical internal carotid artery (arrow), the stump pressure decreased to about 30% of the pre-occlusion level; but subsequent occlusion of the intracranial carotid artery distal to the aneurysm (arrowhead) caused a paradoxical increase in stump pressure. SAP: systemic arterial pressure.
postoperative sequelae attributable to the ischemia of the territory of the anterior cerebral artery, which could not be monitored by the median nerve SEP. 6.3. Paradoxical rise of stump pressure during aneurysm trapping The carotid stump pressure was monitored through the distal lumen of the double lumen balloon catheter placed in the cervical ICA. On inflating the balloon, the stump pressure fell to about 50%; however, contrary to expectations, following occlusion of the intracranial ICA above the aneurysm, the pressure increased to a level above the preocclusion level (Fig. 10). Operative findings also indicated that the aneurysm became tenser. However, on beginning retrograde aspiration, the aneurysm collapsed completely. The rate of blood aspiration was between 10 and 20 ml/min. When the syringe was exchanged and the aspiration temporarily interrupted, the aneurysm again became inflated. The aspirated blood was returned to the patient intravenously. The total volume of aspirated blood differed among the patients, but was between 200 and 500 ml.
7. Discussion 7.1. Retrograde suction decompression technique Flamm [3] was the first to report on a suction decompression method for giant aneurysms, in which the aneurysm was directly punctured using a No. 21 scalp vein needle. In puncturing the aneurysmal wall before treatment of the aneurysm, however, that technique may invite troublesome intraoperative bleeding. Subsequently, Batjer and Samson [1] and Tamaki et al. [13] reported retrograde suction methods in which the cervical ICA is exposed surgically and blood is aspirated from an angiocatheter inserted to the cervical ICA after clamping of both the cervical and intracranial ICA. Scott et al.
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reported a less invasive modification of that method in which retrograde suction was done using a double lumen balloon catheter [8]. They also reported on their experience with the treatment of supraclinoid carotid aneurysms using balloon suction decompression in 12 patients, and described one complication of monocular blindness [9]. Balloon suction decompression technique is extremely effective for dissection of paraclinoid large aneurysms. However, even when the aneurysm is completely deflated, basic surgical procedures for treatment of aneurysms in this location, such as extensive removal of the anterior clinoid process and sufficient exposure of the carotid dural ring, are still essential. With the experience of this method, we found an interesting phenomenon. That is, while monitoring the carotid stump pressure by means of a double lumen balloon catheter placed in the cervical ICA, inflation of the balloon (proximal occlusion) resulted in a sudden decrease in stump pressure to about 50% of the pre-occlusion level; but subsequent occlusion of the intracranial ICA (distal occlusion) resulted in an increase in stump pressure to a level above the pre-occlusion level. This finding indicates that when an aneurysm is incompletely trapped, intra-aneurysmal pressure can be elevated by the retrograde flow through the small remaining branches. Even in cases where the ophthalmic artery, PcomA and anterior choroidal artery have been occluded, similar increases in stump pressure are observed, suggesting the notable participation of retrograde flow from the cavernous ICA branches involving meningohypophyseal trunk. To our knowledge, this paradoxical phenomenon has not been reported previously. However, as Batjer and Samson [1] pointed out, many neurosurgeons may empirically be aware of this phenomenon through their experience that simple trapping of the large aneurysm by cervical ICA clamping and intracranial distal clipping does not adequately soften the lesion because of a brisk retrograde flow through the ophthalmic artery and cavernous branches. This phenomenon also implies that a risk of aneurysmal rupture may increase following such a simple trapping as a result of paradoxical rise in the intra-aneurysmal pressure. There have been several case reports of patients who died due to the fatal rupture of a previously unruptured giant aneurysm after an extracranial – intracranial bypass with proximal carotid artery ligation had been performed [4,10]. It is possible that the cause of rupture in those cases is a hemodynamic change similar to that seen in simple trapping. Thus far, we have used this suction decompression method only in cases of ICA aneurysms, but the indication for its use may theoretically expand with advances in technology to include giant posterior circulation aneurysms. 7.2. Clipping technique Clipping technique for anterior paraclinoid aneurysm was relatively simple, but operation of posterior paraclinoid aneurysm is more difficult. In all 20 cases with posterior paraclinoid aneurysms, we tried to use the tandem clipping method using fenestrated angled clips. However, this method was only possible in 17 cases. In remaining three cases, the ICA had greatly shifted laterally, then fenestrated clipping resulted in severe kinking of the ICA. In these cases, the aneurysm neck was narrowed with a ligature and then large straight clips were applied perpendicularly to the ICA. From our experience, the direction of the ICA is the important factor influencing surgical difficulty. It is important to
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trace the course of the ICA in the AP view angiogram, especially the degree of inclination of the ICA, for the preoperative planning of clipping method. Although parallel clip application is more reasonable to reconstruct the ICA, perpendicular clipping is the alternative option, especially when the ICA is displaced far laterally. Even if the aneurysm is giant size, with complete aneurysm deflation, the conventional technique of neck ligation and clipping technique does not result in significant stenosis of the parent artery.
References [1] H.H. Batjer, D.S. Samson, Retrograde suction decompression of giant paraclinoidal aneurysms. Technical note, J. Neurosurg. 73 (1990) 305 – 306. [2] V.V. Dolenc, A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms, J. Neurosurg. 62 (1985) 667 – 672. [3] E.S. Flamm, Suction decompression of aneurysms. Technical note, J. Neurosurg. 54 (1981) 275 – 276. [4] M. Matsuda, A. Shiino, J. Handa, Rupture of previously unruptured giant carotid aneurysm after superficial temporal-middle cerebral artery bypass and internal carotid occlusion, Neurosurgery 16 (1985) 177 – 184. [5] K. Mizoi, T. Yoshimoto, Permissible temporary occlusion time in aneurysm surgery as evaluated by evoked potential monitoring, Neurosurgery 33 (1993) 434 – 440. [6] K. Mizoi, A. Takahashi, T. Yoshimoto, et al., Combined intravascular and neurosurgical approach for paraclinoid internal carotid artery aneurysms, Neurosurgery 33 (1993) 986 – 992. [7] K. Mizoi, T. Yoshimoto, A. Takahashi, et al., Direct clipping of basilar trunk aneurysms using balloon temporary occlusion, J. Neurosurg. 80 (1994) 230 – 236. [8] J.A. Scott, T.G. Horner, T.J. Leipzig, Retrograde suction decompression of an ophthalmic artery aneurysm using balloon occlusion. Technical note, J. Neurosurg. 75 (1991) 146 – 147. [9] J.A. Scott, Occlusion balloon suction decompression of supraclinoid carotid aneurysms: work in progress, Neuroradiology 33 (1991) S146 (Suppl.). [10] R.M. Scott, H.C. Liu, R. Yuan, et al., Rupture of a previously unruptured giant middle cerebral artery aneurysm after extracranial – intracranial bypass surgery, Neurosurgery 10 (1982) 600 – 603. [11] J. Suzuki, S. Fujimoto, K. Mizoi, et al., The protective effect of combined administration of antioxidants and perfluorochemicals on cerebral ischemia, Stroke 15 (1984) 672 – 679. [12] J. Suzuki, H. Abiko, K. Mizoi, et al., Protective effect of phenytoin and its enhanced action by combined administration with mannitol and vitamin E in cerebral ischemia, Acta Neurochir. (Wien) 88 (1987) 56 – 64. [13] N. Tamaki, S. Kim, K. Ehara, et al., Giant carotid-ophthalmic artery aneurysms: direct clipping utilizing the ‘‘trapping-evacuation’’ technique, J. Neurosurg. 74 (1991) 567 – 572.