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Journal of Neuroradiology
Vol 29, N° 2 - août 2002
pp. 114-121
Doi : JNR-06-2002-29-2-0150-9861-101019-ART13 | |
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© Masson, Paris, 2001 Selective endovascular treatment of intracranial aneurysms using micrus microcoils : preliminary results in a series of 78 patients L.Pierot[1]P.Flandroy[2]F.Turjman[3]J.Berge[4]J.-N.Vallée[5]A.Bonafe[6]S.Bracard[7][1] Service de Radiologie, Hôpital Maison Blanche, Reims, France. [2] Service de Neuroradiologie, Centre Hospitalier, Liège, Belgique. [3] Service de Neuroradiologie, Hôpital Neurologique, Lyon, France. [4] Service de Neuroradiologie Diagnostique et Thérapeutique, Groupe Hospitalier Pellegrin, Bordeaux, France. [5] Service de Neuroradiologie, Groupe Hospitalier Pitié-Salpêtrière, Paris, France. [6] Service de Neuroradiologie, Hôpital Gui de Chauillac, Montpellier, France. [7] Service de Neuroradiologie, Hôpital Neurologique, Nancy, France. Tirés à part : L.Pierot[7] , Service de Radiologie, Hôpital Maison Blanche, 45, Rue Cognacq-Jay, 51092 Reims Cedex. [8] lpierot@chu-reims.fr Purpose : To determine the safety and reliability of a new platinum microcoil (Micrus), in the treatment of intracranial aneurysms. Patients and methods : Seventy-eight patients (28 male and 50 female patients ; age range, 28-83 years ; mean age, 44 years) with 80 intracranial aneurysms were treated in 10 centers in Belgium and France. All aneurysms were smaller than 15 mm. Nine aneurysms (11 %) were located in the posterior circulation and 71 (89 %) in the anterior. Fifty aneurysms (63 %) were ruptured and 30 (37 %) unruptured. Micrus microcoil is a new platinum coil. It is electrically detached with a time of detachment close to 5 seconds. Results : The degree of occlusion of the aneurysm was classified as total in 49 aneurysms (61 %), subtotal in 28 cases (35 %) and incomplete in 3 cases (4 %). Technical complications were encountered in 10 patients (13 %) including parent artery occlusion and thromboembolism (4 cases), coil migration (2 cases) and non-detachment of the coil (2 cases). The immediate morbidity rate was 1.3 % and mortality rate 1.3 %. Conclusion : Micrus microcoils are effective and safe in the selective treatment of ruptured and unruptured intracranial aneurysms. Spherical microcoils are helpful to create a good basket in the aneurysmal sac at the beginning of treatment. aneurysm
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coils
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microcoils Embolisation des anévrismes intracrâniens à l'aide de microspires micrus : résultats préliminaires d'une série de 78 patients Objectif : Évaluer la sécurité et la fiabilité d'une nouvelle spire en platine (Micrus) dans le traitement des anévrismes intracrâniens. Patients et méthodes : Soixante-dix-huit patients (28 hommes et 50 femmes, âgés de 28 à 83 ans, moyenne d'âge : 44 ans) présentant 80 anévrismes intracrâniens ont été traités dans 10 centres belges et français. Tous les anévrismes avaient une taille inférieure à 15 mm. Neufs anévrismes (11 %) étaient localisés sur la circulation postérieure et 71 (89 %) sur la circulation antérieure. Cinquante anévrismes (63 %) étaient rompus et 30 (37 %) non rompus. Le Micrus microcoïl est un nouveau microcoïl en platine, détaché électriquement avec un temps de détachement reproductible de 5 secondes. Résultats : Le degré d'occlusion de l'anévrisme par les coïls a été total dans 49 anévrismes (61 %), subtotal dans 28 cas (35 %) et incomplet dans 3 cas (4 %). Des complications techniques ont été observées dans 10 cas (13 %), en particulier thromboemboliques (4 cas), migration d'un coïl (2 cas), et non détachement d'un coïl (2 cas). La morbidité et la mortalité immédiate ont été respectivement de 1,3 % et 1,3 %. Conclusion : Les microcoïls Micrus sont efficaces et sûrs dans le traitement sélectif des anévrismes intracrâniens rompus et non rompus. Les microcoïls sphériques permettent de créer une bonne cage au sein de l'anévrisme en début de traitement. anévrisme
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coïls
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microcoïls
The use of endovascular techniques in the treatment of intracranial aneurysms has rapidly evolved over the last years. Detachable balloons have been abandoned because of the high percentage of treatment failure, recanalization and recurrence rate. Subsequently, the use of non-detachable coils of various sizes and shapes improved the results of endovascular treatment [1]. The next step was the development of controlled-detachable coils [4] that widened the indications of the endovascular treatment from the non-surgical aneurysms like basilar artery aneurysms [8] to surgical one like anterior communicating aneurysms [7]. The first controlled-detachable coil was electrolytically detachable [4]. Several detachable coils are now available, whose detachment is electrically or mechanically controlled [5].
Despite the dramatic evolution represented by the availability of controlled-detachable coils, the width of the neck rapidly appears as a limitation of the endovascular treatment[11]. The use of the « remodelling technique »[6] allows the treatment of wide neck aneurysms. A non-detachable balloon is placed in the parent vessel in front of the neck of the aneurysm and coils are deposited into the aneurysmal sac under the protection of the inflated balloon. Other approaches are proposed for the treatment of wide neck aneurysms like 3D coils. Stents are also potentially useful devices in the treatment of wide neck aneurysms[10]. The goal of the endovascular treatment is to exclude the aneurysmal sac and neck from the circulation. Recurrence may be observed at the level of the neck at long term follow-up angiography[3], especially if the sac and neck are not densely packed at the end of the treatment. Micrus microcoils are newly designed microcoils, with very short detachment time. Spherical Micrus microcoils are potentially useful to improve the quality of the basket created in the aneurysmal sac with the first coil. We report the preliminary experience of the Belgian and French neuro-interventional teams with the use of this device.
From November 2000 to April 2002, 78 patients presenting 80 intracranial aneurysms were treated using Micrus microcoils in 10 Interventional Neuroradiology Centers in France and Belgium. Fifty patients were female (64 %) and 28 were male (36 %). The patients ranged in age from 28 to 83 years with a mean of 44 years. Fifty aneurysms (63 %) were ruptured and 30 (37 %) were unruptured. Aneurysm location is detailed in tableau 1. All aneurysms were smaller than 15 mm. The size of the aneurysm was between 1 and 5 mm in 24 cases, between 6 to 10 mm in 51 cases and greater than 11 mm in 5 cases. The ratio between aneurysmal sac and neck diameter was between 1 and 2 in 49 aneurysms (61 %) and > 2 in 31 aneurysms (39 %).
The Micrus ACT Microcoil Systemä includes the detachable platinum embolic coil pre-attached to a Device Positioning Unit.
The Micrus Microcoils are available in spherically shaped configurations (Micrus MicruSphereä) as well as helically shaped configurations (HeliPaqä) of various diameters and dimensions. The Micrus Micru Sphereä spherical detachable platinum coil provides 3-dimensional anatomical conformance within the aneurysm during embolization figure 1. The Micru Sphere Platinum Microcoils automatically assume their spherical shape upon deployment. MicruSphere Platinum Microcoils are available in both 10 and 18 systems. The HeliPaqä helical coils work to further exclude the aneurysm from cerebral circulation. HeliPaq Platinum Microcoils are available in a 10 system. The Micrus Microcoil System provides a « frame and fill » technique wherein the aneurysm is first framed by deploying spherically shaped Microcoil that assumes an anatomically compliant frame within the aneurysm's fragile perimeter. This frame is then rapidly filled with helically shaped Microcoils until the aneurysm is completely occluded.
The Micrus Microcoil Delivery System consists of three components : the Micrus ACT Microcoil System, which consists of a platinum embolic coil (Microcoil), attached to a Device Positioning Unit, the Detachment Control Box, and the Connecting Cable.
The detachment of the Micrus Microcoil from the Device Positioning Unit is accomplished through heat-initiated shearing of a highly oriented, high tensile strength polyethylene fibre. The operator controls a Detachment Control Box, in which electrical energy heats a platinum resistive heating coil at the distal end of the Device Positioning Unit. This initiates heat shearing of the polyethylene fibre, which holds the Microcoil to the Device Positioning Unitfigure 2. This detachment occurs cleanly (no release of any materials into the patient's bloodstream upon coil detachment). Detachment is indicated when the 5-second intermittent tone stops and the green detachment light goes out on the Micrus Detachment Control Box. Once the fibre shears, the Microcoil is detached from the Device Positioning Unit, and the Device Positioning Unit is withdrawn and discarded. Two generations of detachment systems were successively available. To ensure reliable first fire detachment, Micrus optimized manufacturing processes and applied pre-tensioning to the detachment site, creating the second generation of coils. The Micrus Detachment Control Box is a self-contained, battery-operated device, which provides the controlled electrical energy for detachment of the Microcoil from the Device Positioning Unit. The Detachment Control Box has an on/off button, and a detachment cycle start button, as well as voltage and current displays and fault and low battery indicators. When the clinician depressed the detach button the Detachment Control Box outputs 7.8 volts to the resistance-heating coil for 1 second, immediately followed by 6.5 volts for 4 seconds at a maximum current of 200 mA. The Micrus Connecting Cable carries the necessary electrical current from the power supply, allowing detachment of the Microcoil from the Device Positioning Unit.
All procedures were performed under general anaesthesia. A four vessels angiogram was initially performed including 3D-angio when available. Anterior and posterior circulation were evaluated. Morphology of the aneurysm was studied as well as presence of vasospasm in case of ruptured aneurysms. Endovascular treatment was performed immediately after diagnostic cerebral angiography in most ruptured aneurysms to protect the patient from aneurysm re-rupture. In unruptured aneurysms, endovascular treatment was performed after the diagnostic angiography if the patient gave his informed consent before the procedure and if the treatment was considered feasible with an acceptable risk of complications by the physician. In other cases, the best strategy of treatment was determined by the neurosurgeons and neuroradiologists. All procedures were performed under full heparinization and aspirin was added in case of unruptured aneurysms. In all cases, spherical coils were initially delivered in the aneurysmal sac to obtain a good frame. Secondarily, helical microcoils were added to obtain dense packing. Remodelling technique was used in few cases. Postoperatively, patients were left under heparin or aspirin therapy.
The goal was to precisely evaluate the feasibility and safety of the endovascular treatment of intracranial aneurysm using Micrus microcoils. All technical problems were monitored as well as clinical complications. The occlusion rate at the end of the procedure was classified according to Cognard et al.[2] :
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total occlusion when the sac and neck were densely packed ;
- subtotal occlusion when the sac was occluded but with a suspicion of a neck remnant or an obvious tiny neck remnant ;
- incomplete occlusion when the aneurysmal sac was loosely packed or if a persistant opacification of the sac or neck was observed.
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A total of 457 coils (135 spherical and 322 helical) were used. A total of 141 coils had the first detachment system. In all aneurysms, 1 to 4 spherical coils (mean : 1,7) were initially delivered to obtain a good frame figure 3figure 4andfigure 5. Helical microcoils (0 to 14 ; mean : 4) were then added to obtain dense packing figure 3figure 4figure 5figure 6andfigure 7.
Non detachment of the coil was observed in 2 cases with the first generation of coils and was not observed with the second generation. No premature detachment was observed. With this second generation, detachment occurs quickly (less than 5 seconds) and consistently (always less than 5 seconds, whether the initial or the last coil used to pack the aneurysm).
At the end of the first procedure, the occlusion rate of the 80 aneurysms was total in 49 cases (61 %), subtotal in 28 cases (35 %) and incomplete in 3 cases (4 %). At the present time no complementary treatment was undertaken even in cases of incomplete treatment. In all patients with incomplete occlusion, the occlusion rate was close from 90 % and an angiographic follow-up is performed.
Ten technical complications without any clinical modifications (13 %) were observed during the treatment. The complications included parent artery occlusion and thromboembolism (4 cases), coil migration (2 cases), non detachment of the coil (2 cases), non deployment of the coil (1 case) and protrusion of the coil (1 case). Non detachment of the coil was observed with the first generation of Micrus microcoils. After the improvement of the detachment system, a quick detachment was always observed. Coil rupture was not observed in our series.
There was 1 peri-procedural death in a patient presenting a ruptured aneurysm with a high WFNS grade. Postoperative neurological deterioration was observed in 1 case. A third nerve palsy was observed during 48 hours after the treatment. Overall the morbidity and the mortality rates were evaluated to 1.3 % and 1.3 % respectively.
The introduction of Guglielmi Detachable Coils (GDC, Target-Boston) has completely modified the strategy of treatment of intracranial aneurysms [2][3][6][9]. Before this important step, management of ruptured and unruptured aneurysms was mainly performed by neurosurgical approach and endovascular treatment using micro-balloons or non controlled detachable coils was dedicated to unclipable aneurysms. Since the introduction of GDC coils, the indications of endovascular treatment have progressively enlarged from difficult surgical cases like basilar artery aneurysms [8] to anterior circulation aneurysms like anterior communicating, carotid and middle cerebral aneurysms [2][6]. However, some anatomical features can constitute a limitation in the use of the endovascular treatment. The size of the aneurysmal neck is critical in the feasibility, efficacy and safety of the endovascular treatment [11]. Indeed, in case of wide-necked aneurysms, the stabilization of the coils may be sometimes difficult. For this reason, J. Moret et al. proposed in 1997 the use of the “remodelling technique” [6]. It involves the temporary inflation of a non-detachable balloon in front of the aneurysm neck during the placement of the coils. Three dimensional-coils and Trispan have also been proposed to improve the treatment of wide-neck aneurysms.
Spherical microsphere microcoil appears to be a device allowing the creation of a good basket in the aneurysmal sacfigure 3figure 4andfigure 5. As we know, it is very important to obtain a dense packing of the coils in the aneurysmal sac[2]. If a good frame is created with the first coils, the aneurysm can then be correctly filled with coilsfigure 3figure 4figure 5figure 6andfigure 7. Even in some cases of wide-neck aneurysms, it was possible to obtain good packing of the aneurysmal sac without using the remodelling technique. Moreover, in one case, spherical MicruSphere microcoils permitted to perform the treatment of wide-necked aneurysm which was impossible to treat with other 3D coils. It should be mentioned, that several spherical coils can be introduced in the same aneurysm improving the quality of the initial basket and final filling. GDC are electrolytically detached. Mechanical detachable coils are also available[5]. The detachment system has to be safe and quick. The detachment system is considered safe, if detachment is always obtained when required, involuntary detachment is not observed and the proximal portion of the coil is stable after the detachment. The time of de tachment has to be short to avoid increase in the length of the procedure. The safety of the detachment system of some coils is at the present time not complete. The duration of the detachment is also irregular and despite a tremendous improvement since the first system, it remains quite long (between few seconds and few minutes). Our study demonstrated the safety of the detachment system of the Micrus microcoils. The detachment was always obtained when required with the new version of the coil. With the first version, the coil was impossible to detach in 2 cases and had to be pulled back without any clinical modification. Involuntary detachment was not observed in our series. Deplacement of the proximal portion of the coil immediately after the detachment was also not observed. The duration of Micrus microcoil detachment was quite regular and short close to 5 seconds. Morphological results obtained with MicruSphere microcoils are not different from those obtained with GDC coils. In the large USA series[9], complete occlusion was obtained in 70.8 % of small aneurysms with small neck and in 31.2 % of small aneurysms with wide neck. In our series mixing small and wide neck aneurysms, complete occlusion was obtained in 61 %. In the large series of Cognard et al.[2], complete occlusion was initially obtained in 56 % of cases. The rate of recurrences was not studied in our series, and long-term follow-up is needed to evaluate this factor. The rate of technical complications is in the same range as in series of patients treated with GDC coils[2][9]. There was no aneurysm perforation in this series. Thromboembolism was the most frequent complication and is not specifically related to the type of coil used. Non detachment of the coil was observed with the first version of the coil. Coil migrations, coil protrusion and non deployment of the coil are not related to the type of coil used. The morbidity and mortality rates are lower than those observed in other series[2][9]. This difference is probably explained by different bias. The population of these studies are not exactly the same. Our group contains a high percentage of unruptured aneurysms. No large or giant aneurysms were included in our study. Moreover, the study was conducted in centers treating intracranial aneurysms with coils since many years. Then, because there is certainly a learning curve in the use of controlled-detachable coils whatever the type of detachment system, our series included patients treated by neuroradiologists having a great experience with the use of coils in intracranial aneurysms. Finally, because our series is more recent than the largest series of patients treated with GDC, the devices used to access to the aneurysms (guiding catheters, microcatheters, guidewires) were probably not the same than those used in the past. In summary, the detachment system of the micrus microcoils is reliable and safe and the detachment is obtained quickly (in less than 5 seconds) and consistently. Spherical microcoils are helpfull to improve the quality of the frame obtained with the first coils. The following investigators participated in this study and provided data for this publication : J. Berge, X. Barreau (Bordeaux) ; P. Courtheoux (Caen) ; P. Flandroy (Liège) ; F. Turjman (Lyon) ; B. Viaud-Rivallin, G. Bourbotte, B. Jean, I. Granier, A. Bonafé (Montpellier) ; A. de Kersaint-Gilly (Nantes) ; R.Anxionnat, A. Lebedensky, S. Bracard, L. Picard (Nancy) ; A.Biondi, J.-N. Vallée – Hôpital de la Pitié-Salpêtrière (Paris) ; D. Trystram, J.-F. Meder - Centre Hospitalier Sainte-Anne (Paris) ; A. Guillaume, D. Breidt, F. Bouquigny, L. Pierot (Reims) [1] Casasco A, Arnaud O, Gobin P, Aymarda, George B, Cophignon J, Merland JJ. Anévrysmes géants intracrâniens. Traitement endovasculaire électif par des spires métalliques. Neurochirurgie 1992 ; 38 : 18-26. [2] Cognard C, Weill A, Castaings L, Rey A, Moret J. Intracranial Berry Aneurysms : Angiographic and Clinical Results after Endovascular Treatment. Radiology 1998 ; 206 : 499-510. [3] Cognard C, Weill A, Spelle L, Piotin M, Castaings L, Rey A, Moret J. Long-term Angiographic Follow-up of 169 Intracranial Berry Aneurysms Occluded with Detachable Coils. Radiology 1999 ; 212 : 348-356. [4] Guglielmi G, Vinuela F, Dion J, Duckwiler G. Electrothrombosis of saccular aneurysms via endovascular approach. J Neurosurg 1991 ; 75 : 8-14. [5] Murphy KJ, Houdart E, Szopinski KT, Levrier O, Guimaraens L, Kuhne D et al. A Report of the Clinical Use of the Detach-18 Mechanial Detachable Platinum Coil in 41 patients. AJNR Am J Neuroradiol 2001 ; 22 : 341-344. [6] Moret J, Cognard C, Weil A, Castaings L, Rey A. La technique de reconstruction dans le traitement des anévrismes intracrâniens à collet large. J Neuroradiol 1997 ; 24 : 30-44. [7] Moret J, Pierot L, Boulin A, Castaings L, Rey A. Endovascular treatment of anterior communicating artery aneurysms using GDC coils. Neuroradiology 1996 ; 38 : 800-805. [8] Pierot L, Boulin A, Castaings L, Rey A, Moret J. Selective occlusion of basilar artery aneurysms using controlled-detachable coils : report of 35 cases. Neurosurgery 1996 ; 38 : 948-954. [9] Vinuela F, Duckwiler G, Mawad M. Guglielmi detachable coil emolization of acute intracranial aneurysm : perioperative anatomical and clinical outcome in 403 patients. J Neurosurg 1997 ; 86 : 475-482. [10] Wakhloo AK, Lanzino G, Lieber BB, Hopkins LN. Stents for Intracranial Aneurysms : The Beginning of a New Endovascular Era ? Neurosurgery 1998 ; 43 : 377-379. [11] Zubillaga A, Guglielmi G, Vinuela F, Duckwiller GR. Endovascular Occlusion of Intracranial Aneurysms with Electrically detachable Coils : Correlation of Aneurysm Neck Size and Treatment Results. AJNR 1994 ; 15 : 815-820.  Figure 1. Spherical microcoil (Micrus MicruSphereä). Figure 2. Detachment system :  Figure 2. a) before detachment, the microcoil is attached to the device positioning unit by a high tensile strenght polyethylene fiber ;  Figure 2. b) after detachment. Heat shearing of the polyethylene fiber. Figure 3. Right unruptured middle cerabral artery aneurysm :  Figure 3. a) right internal carotid angiography (oblique view) showing a large neck, round aneurysm of the middle cerebral artery ;  Figure 3. b) 3D angiogram showing the neck of the aneurysm ;  Figure 3. c) road mapping image and  Figure 3. d) non substracted internal carotid artery angiogram showing the frame obtained after the placement of a first spherical microcoil ;  Figure 3. e) non substracted and  Figure 3. f) substracted images of the right internal carotid artery angiogram at the end of the treatment showing complete occlusion of the aneurysmal sac. Fig. 4. — Left unruptured carotido-ophthalmic aneurysm :  a) left internal carotid artery angiogram showing a large neck carotido-ophthalmic aneurysm ;  b) road mapping image of the left internal carotid artery after placement of a first spherical microcoil showing the frame obtained ;  c) lateral non substracted non injected image showing the dense packing of the coils at the end of the treatment ;  d) left internal carotid artery angiogram (lateral view) showing complete occlusion of the aneurysm at the end of the treatment. Fig. 5. — Ruptured right posterior communicating artery aneurysm :  a) right internal carotid artery angiogram (lateral view) showing a multilobulated, small neck aneurysm of the posterior commu nicating artery ;  b) non substracted and  c) substracted images of the right internal carotid artery angiogram after placement of a first spherical microcoil showing filling of the lobules by the loops of the coil ;  d) non substracted and  e) substracted images of the right internal carotid artery angiogram after the treatment of the aneurysm showing dense packing of the coils in the aneurysmal sac. Figure 6. Ruptured anterior communicating artery aneurysm : Left internal carotid artery angiogram :  a) oblique view and  b) 3D angio showing the small neck of the aneurysm.  c) Left internal carotid artery aneurysm showing complete occlusion of the aneurysm at the end of the treatment. Figure 7. Fig. 7. — Ruptured left middle cerebral artery aneurysm. Left internal carotid artery angiography :  a) oblique view and  b) 3D angio showing a small, large neck aneurysm of the M1 segment.  c) Non substracted and  d) substracted images of the left internal carotid artery angiogram at the end of the treatment showing complete occlusion of the aneurysmal sac. |
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© 2002 Elsevier Masson SAS. Tous droits réservés.
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