Microsurgery of residual or recurrent complex intracranial aneurysms after coil embolization - a quest for the ultimate therapy.

The long-term stability of coil embolization (CE) of complex intracranial aneurysms (CIAs) is fraught with high rates of recanalization. Surgery of precoiled CIAs, however, deviates from a common straightforward procedure, demanding sophisticated strategies. To shed light on the scope and limitations of microsurgical re-treatment, we present our experiences with precoiled CIAs. We retrospectively analysed a consecutive series of 12 patients with precoiled CIAs treated microsurgically over a 5-year period, and provide a critical juxtaposition with the literature. Five aneurysms were located in the posterior circulation, 8 were large-giant sized, 5 were calcified/thrombosed. One presented as a dissecting-fusiform aneurysm, 9 ranked among wide neck aneurysms. Eight lesions were excluded by neck clipping (5 necessitating coil extraction); 1 requiring adjunct CE. The dissecting-fusiform aneurysm was resected with reconstruction of the parent artery using a radial artery graft. Three lesions were treated with flow alteration (parent artery occlusion under bypass protection). Mean interval coiling-surgery was 4.6 years (range 0.5-12 years). Overall, 10 aneurysms were successfully excluded; 2 lesions treated with flow alteration displayed partial thrombosis, progressing over time. Outcome was good in 8 and poor in 4 patients (2 experiencing delayed neurological morbidity), and mean follow-up was 24.3 months. No mortality was encountered. Microsurgery as a last resort for precoiled CIAs can provide-in a majority of cases-a definitive therapy with good outcome. Since repeat coiling increases the complexity of later surgical treatment, we recommend for this subgroup of aneurysms a critical evaluation of CE as an option for re-treatment.

How I do it: coil extraction and clip reconstruction of a previously coiled giant middle cerebral artery aneurysm.

BACKGROUND: Microsurgical clipping of previously coiled intracranial aneurysms can be technically challenging. We present the case of a 48-year-old female with a partially coiled, previously ruptured giant middle cerebral artery aneurysm and the associated technical nuances. METHODS: We performed a successful coil extraction and clip reconstruction of this aneurysm using an ultrasonic aspirator and stacked fenestrated aneurysm clips. CONCLUSION: Coil extraction and clip occlusion of previously coiled intracranial aneurysms is a complex and technically challenging procedure but can be performed safely and effectively when employed judiciously.

Management of Previously Failed Coiling and Clipping of a Middle Cerebral Artery Aneurysm.

Endovascular coiling techniques have emerged as an alternative and effective approach for treating intracranial aneurysms. However, in some cases, previously coiled aneurysms may require secondary treatment with surgical clipping, presenting a more complex challenge compared with the initial intervention.1,2 We present the case of a 39-year-old man with a residual class III Raymond-Roy occlusion partially coiled aneurysm at the left middle cerebral artery bifurcation (Video 1). Faced with the risks of rerupture, the patient underwent microsurgical treatment after providing consent. Despite successful initial microsurgical clipping, postoperative complications arose due to coil protrusion into the middle cerebral artery bifurcation, resulting in thrombotic occlusion of the frontal M2 branch. Emergency repeat microsurgical intervention and administration of a thrombolytic agent were performed to address complications, ultimately preserving blood flow. Subsequent endovascular placement of a flow-diverting stent 7 weeks after discharge confirmed complete occlusion of the aneurysm. The patient had no neurological deficit on follow-up. When planning microsurgical clipping of an aneurysm previously treated with coils, it is critical to consider coil placement, as there is a risk of prolapse if the coil is in the neck of the aneurysm. Thrombosis of the cerebral arteries is a potential complication of microsurgical clipping of partially coiled intracranial aneurysms, and injection of a fibrinolytic agent into thrombosed arterial branches may be an effective intraoperative method for treating intra-arterial thrombosis.3 This case illustrates the challenges associated with treating partially coiled aneurysms, highlighting the significance of careful planning when considering microsurgical treatment.

Double-catheter technique for the embolization of recurrent cerebral aneurysms: A single-center experience.

Background: Recurrent cerebral aneurysms have complex shapes and are often technically challenging to treat with a single microcatheter. This study evaluates the clinical characteristics and treatment outcomes of patients who received double-catheter coil embolization for recurrent cerebral aneurysms. Methods: Patients who underwent double-catheter coil embolization at our institution between April 2011 and March 2022 for recurrent aneurysms were included in the study. Baseline characteristics, course to recurrence, details of the procedures, and outcomes after endovascular treatment were retrospectively analyzed based on past medical records. Results: Eight patients with recurrent aneurysms were treated with the double-catheter technique. One patient had a subarachnoid hemorrhage due to a rupture of a recurrent aneurysm and the others had radiological recurrence during follow-up. The initial treatment for the aneurysm was clipping in one case and coiling in seven cases. All the aneurysms were located at bifurcation sites. During retreatment, balloon remodeling technique was used in five cases. Angiographic features immediately after the treatment included complete occlusion in one case, neck remnant in three cases, and dome filling in four cases. There were no procedure-related severe complications, besides preexisting oculomotor nerve palsy due to the mass effect of the aneurysm worsened in one patient. The mean follow-up period after retreatment was 4.3 years. There was one case of recurrence after retreatment in which additional endovascular coiling was necessary. Conclusion: This study demonstrated that the double-catheter technique could be a safe and useful treatment option for patients with recurrent aneurysms at bifurcation sites.

Identifying risk factors for perioperative thromboembolic complications in patients treated with the Woven EndoBridge device.

INTRODUCTION: Woven EndoBridge (WEB) is a new endovascular treatment option for wide necked bifurcation aneurysms. Results from the WEB-IT trial showed a 0% risk of thromboembolic complications within 30 days post-op but the rate reported in the literature is as high as 10%. We are exploring potential risk factors associated with immediate thromboembolic complications in patients treated with the WEB device. METHODS: Retrospective study of forty-two patients with intracranial aneurysms who were treated with WEB at a single center from 2019-2021. Data was collected on patient demographics, comorbidities, aneurysm characteristics, procedural details, and hospital course. Bivariate analyses were performed to compare patients who experienced a periprocedural ischemic stroke to those who did not. Multiple logistic regression modeling was performed to identify independent risk factors for thromboembolic complications. RESULTS: Of the 42 patients that were treated with WEB, 6 suffered an ischemic stroke (AIS). These patients were more likely to have an underlying diagnosis of arrythmias (p value = 0.007). Furthermore, they had a median angle of 32.0° in the true neck view on diagnostic angiogram compared to 19.5° (p value = 0.046). Lastly, they had a longer procedure length of 228 min compared to 178 min (p value = 0.002). Patients with thromboembolic complications had a longer length of stay in the hospital and worse outcomes at three months follow up. On logistic regression modeling, these risk factors did not reach statistical significance. CONCLUSION: Risk factors of thromboembolic complications after WEB placement include cardiac arrythmias, acute aneurysmal angle in the true neck view and a longer procedure length.

Computational fluid dynamics (CFD) analysis in a ruptured vertebral artery dissecting aneurysm implanted by Pipeline when recurrent after LVIS-assisted coiling treatment: Case report and review of the literatures.

BACKGROUNDS: Hemodynamics plays an important role in the natural history of the process of rupture and recurrence of intracranial aneurysms. This study aimed to investigate the role of hemodynamics for recurrence in a vertebral artery dissecting aneurysm (VADA). METHODS: A patient with a ruptured VADA firstly treated by low-profile visualized intraluminal support (LVIS)-assisted coiling, and was implanted with a Pipeline Embolization Device (PED) after aneurysm recurrence. Finite element analysis and computational fluid dynamics simulations were conducted in 6 serial imaging procedures, and the calculated hemodynamics was correlated with aneurysm recurrence. RESULTS: Wall shear stress (WSS) was not effectively suppressed, resulting in aneurysm recurrence with initial entry tear to occur above the protuberance after 7 months of LVIS stent-assisted coiling. With the implantation of PED, WSS, inflow stream and velocity at the aneurysm neck significantly decreased. During the 3-month follow-up after PED deployment, there was significant shrinkage of the sac and the blood flow in the sac was reduced considerably. The 27-month follow-up after PED deployment indicated the aneurysm was stable. CONCLUSIONS: The present case study suggests that insufficient suppression of high WSS and high inflow velocity at the neck of the parent artery, especially near the posterior inferior cerebellar artery, might be associated with aneurysm recurrence.

Long-term outcomes of coils embolization for superior hypophyseal artery aneurysms.

Objective: Superior hypophyseal artery (SHA) aneurysms are intradural, and their rupture can result in subarachnoid hemorrhage. Considering the related surgical difficulty and anatomical restrictions, endovascular treatment (EVT) is considered the most favorable modality for SHA aneurysms; however, the long-term outcomes of EVT have rarely been reported. The study assessed the incidence of and risk factors for recurrence of SHA aneurysms after EVT as well as the correlation factors for SHA aneurysm rupture. Methods: We included 112 patients with SHA aneurysms treated with EVT at our facility between 2009 and 2020. Here, EVT included non-stent-assisted (simple or balloon-assisted) or stent-assisted coiling. Flow diverter was not included because it was barely used due to its high cost under our national insurance's limitation, and a high proportion of ruptured aneurysms in our series. Univariate and multivariate logistic regression was performed to evaluate the correlation factors for SHA aneurysm rupture, along with the incidence of and risk factors for post-EVT SHA aneurysm recurrence and re-treatment. Results: In our patients, the mean angiographic follow-up period was 3.12 years. The presence of type IA or IB cavernous internal carotid artery (cICA) was strongly correlated with SHA aneurysm rupture. Recurrence occurred in 17 (13.4%) patients, of which only 1 (1.4%) patient had received stent-assisted coiling. All cases of recurrence were observed within 2 years after EVT. The multivariate logistic regression results showed that ruptured aneurysm and non-stent-assisted coiling were independent risk factors for aneurysm recurrence. Of the 17 cases of aneurysm recurrence, 9 (52.9%) received re-treatment. Moreover, aneurysm rupture was the only factor significantly correlated with re-treatment in multivariate logistic regression. No re-recurrence was observed when a recurrent aneurysm was treated with stent-assisted coiling. Conclusion: Type I cICA was common factor for aneurysm rupture. Although flow-diverter treatment serves as another suitable technique that was not compared with, coils embolization was effective treatment modality for SHA aneurysms, leading to low recurrence and complication rates, especially with stent use. All cases of recurrence occurred within 2 years after EVT; they were strongly associated with prior aneurysm rupture. Further stent-assisted coiling was noticed to prevent re-recurrence.

Risk of intracranial aneurysm recurrence after microsurgical clipping based on 3D digital subtraction angiography.

OBJECTIVE: Current knowledge of recurrence rates after intracranial aneurysm (IA) surgery relies on 2D digital subtraction angiography (DSA), which fails to detect more than 75% of small aneurysm remnants. Accordingly, the discrimination between recurrence and growth of a remnant remains challenging, and actual assessment of recurrence risk of clipped IAs could be inaccurate. The authors report, for the first time, 3D-DSA-based long-term durability and risk factor data of IA recurrence and remnant growth after microsurgical clipping. METHODS: Prospectively collected data for 305 patients, with a total of 329 clipped IAs that underwent baseline 3D-DSA, were evaluated. The incidence of recurrent IA was described by Kaplan-Meier curves. Risk factors for IA recurrence were analyzed by multivariable Cox proportional hazards and logistic regression models. RESULTS: The overall observed proportion of IA recurrence after clipping was 2.7% (9 of 329 IAs) at a mean follow-up of 46 months (0.7% per year). While completely obliterated IAs did not recur during follow-up, incompletely clipped aneurysms (76 of 329) demonstrated remnant growth in 11.8% (3.4% per year). Young age and large initial IA size significantly increased the risk of IA recurrence. CONCLUSIONS: The findings support those in previous studies that hypothesized that completely clipped IAs have an extremely low risk of recurrence. Conversely, the results highlight the significant risk posed by incompletely clipped IAs. Young patients with initial large IAs and incomplete obliteration have an especially high risk for IA recurrence and therefore should be monitored more closely.

A case of recurrent aneurysm resulting from dual antiplatelet plus anticoagulation after confirmed aneurysm closure following coil-assisted flow diversion.

Dual antiplatelet therapy (DAPT) is a management cornerstone for intracranial aneurysms treated with flow diversion. However, combined dual antiplatelet plus anticoagulation (triple therapy) can be indicated in some patients with important associated risks. Here we present the case of a 72-year-old woman with prior history of subarachnoid hemorrhage who was started on triple therapy (enoxaparin and DAPT) following successful flow diversion of an enlarging but unruptured left fetal posterior communicating artery aneurysm. Her post-procedural course was complicated by in-stent thrombosis in the setting of a missed ticagrelor dose and subsequent development of deep venous thrombosis and pulmonary embolism. An early follow-up angiogram confirmed occlusion of the aneurysm. However, after initiation of triple therapy, the aneurysm partially recanalized and her symptoms recurred. Subsequent discontinuation of enoxaparin lead to prompt aneurysm re-occlusion. To our knowledge, this is the first reported instance of confirmed intra-aneurysmal thrombolysis in a successfully treated aneurysm after triple therapy initiation.

Utility of skull X-rays in identifying recurrence of coiled cerebral aneurysms.

OBJECTIVE: A high rate of cerebral aneurysm recurrence following endovascular coiling has prompted the use of digital subtraction angiography (DSA) for interval follow-up. However, the utility of skull x-rays as an alternative screening method for aneurysm recurrence is unproperly characterized. METHODS: Retrospective review of a prospective registry of ruptured and unruptured cerebral aneurysms. Anteroposterior and lateral skull x-rays were obtained immediately at the end of the procedure and at 6-month follow-up. Aneurysm recurrence was defined by comparing post-procedure and 6-month DSA imaging. A true positive was defined as a change in coil mass morphology on at least one projection with aneurysm recurrence on DSA, and a true negative defined as a stable coil mass on both projections and no recurrence on DSA. Receiver operating characteristic area under the curve (AUC) statistics was used to assess the performance of skull x-rays in identifying aneurysm recurrence. RESULTS: A total of 118 cerebral aneurysms were evaluated with DSA imaging and skull x-rays. A change in coil mass morphology on one projection of skull x-rays correctly detected all true recurrences with a sensitivity of 100% (95% confidence interval [CI], 91-100%). Skull x-rays failed to identify a stable aneurysm coil mass in 15 cases, with a specificity of 79% (68-88%). Skull x-rays performed with AUC 0.8958 (95% CI, 0.8490-0.9431) in identifying aneurysm recurrence. CONCLUSIONS: The findings of our study suggest that skull x-rays may represent a lowcost, non-invasive screening tool to rule out aneurysm recurrence, which can potentially aid in decreasing the utilization of DSA in the follow-up of patients with coiled cerebral aneurysms.

Predictive Value of Mean Platelet Volume for Aneurysm Recurrence in Patients with Aneurysmal Subarachnoid Hemorrhage After Endovascular Treatment.

BACKGROUND: The purpose of this study was to explore the relationship between mean platelet volume (MPV) and aneurysm recurrence in aneurysmal subarachnoid hemorrhage (aSAH) patients who received endovascular treatment for intracranial aneurysms. METHODS: Data were collected and analyzed from 204 aneurysms in 187 aSAH patients who received endovascular treatment at our institution between January 2014 and January 2019. All aneurysms were divided into 2 groups based on aneurysm recurrence. Univariate and multivariable analyses were performed to investigate whether MPV was an independent predictor of aneurysm recurrence. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were determined. RESULTS: A total of 42 (20.6%) aneurysms recurred. Recurrent aneurysms had a lower rate of complete obliteration (P = 0.002) and lower MPV values on admission (P < 0.001) than nonrecurrent aneurysms. The multivariable analysis showed that the Raymond-Roy classification (odds ratio [OR]: 3.217, 95% confidence interval [CI]: 1.308-7.913, P = 0.011) and MPV (OR: 0.247, 95% CI: 0.151-0.402, P < 0.001) was significantly associated with aneurysm recurrence. The ROC curve analysis determined that MPV could predict aneurysm recurrence with an AUC of 0.846 (95% CI: 0.788-0.892, P < 0.001). An MPV ≤9.9 fL could predict aneurysm recurrence with a sensitivity of 80.95% and a specificity of 79.63%. CONCLUSIONS: A low perioperative MPV may be associated with aneurysm recurrence in aSAH patients who receive endovascular treatment for intracranial aneurysms. Therefore, MPV can be used in clinical settings to screen for patients at high risk for aneurysm recurrence.

Early Intracranial Aneurysm Recurrence after Microsurgical Clip Ligation: Case Report and Review of the Literature.

Microsurgical clip ligation is considered a definitive treatment for intracranial aneurysms (IAs), resulting in low rates of local recurrence that range from 0.2 to 0.5% and a latency period that averages about a decade. Our case report describes an early asymptomatic recurrence (i.e., without sentinel headache or seizure) less than 1 year after this 20-year-old woman underwent clip ligation of a ruptured anterior communicating artery (AComA) aneurysm. At recurrence, the patient underwent coiling of the regrowth; follow-up imaging at 6 and 18 months demonstrated complete IA occlusion. To review the putative risk factors of this rare phenomenon, the authors searched the PubMed database using the keywords "intracranial aneurysm," "recurrence," and "clipping" in various combinations. In the seven cases identified, all occurred in initially ruptured IA, which was often at the AComA, and six of seven patients were younger than 50 years old. Although most IA remnants grow slowly, early recurrence may represent a more aggressive biological behavior that warrants special attention in younger patients, positive rupture status, and unintended remnant of any size. In such a constellation, early imaging follow-up within the first 6 months may be warranted to rule out early IA recurrence.

Risk of Aneurysm Residual Regrowth, Recurrence, and de Novo Aneurysm Formation After Microsurgical Clip Occlusion Based on Follow-up with Catheter Angiography.

INTRODUCTION: Established guidelines for radiologic surveillance after microsurgical treatment of intracranial aneurysms are lacking in the literature because of small sample sizes, poor definitions, and heterogeneous use of imaging modalities. We aimed to propose clinically meaningful definitions for postoperative aneurysm residual, recurrence, and de novo aneurysm formation and to analyze our long-term follow-up catheter angiography results in patients with microsurgically treated intracranial aneurysms. METHODS: A retrospective review of all aneurysms treated microsurgically in a consecutive, single-surgeon series from 1997 to present identified patients with long-term follow-up catheter angiography (>1 year after surgery). Clinical and radiologic data were collected for analysis. RESULTS: We identified 240 patients harboring 380 aneurysms (mean follow-up time, 6.0 ± 3.3 years per patient; range, 1.0-16.8 years). Postoperative residuals were present in 16 out of 346 clipped aneurysms (4.6%), of which only 3 were left unintentionally. Two out of 16 residual aneurysms (12.5%) demonstrated regrowth, with a regrowth risk of 2.1% per year from 93.6 patient-years of angiographic follow-up. Of 326 aneurysms with no postoperative residual, 5 (1.5%) demonstrated aneurysm recurrence, with a recurrence risk of 0.26% per year from 1931.9 patient-years of angiographic follow-up. Eight de novo aneurysms were identified in 240 patients (3.3%), with a risk of 0.6% per year from 1441.9 patient-years of angiographic follow-up. CONCLUSIONS: Microsurgically treated aneurysms have a very low risk of postoperative residuals and aneurysm recurrence. Growth of residuals and de novo aneurysm formation justify following up with catheter angiography 3 to 5 years after microsurgical clipping.

Cell Therapy for Intracranial Aneurysms: A Review.

One in five patients undergoing endovascular coiling (the current standard of care for treating intracranial aneurysms) experience a recurrence of the aneurysm as a result of improper healing. Recurrence remains the only major drawback of the coiling treatment and has been the focus of many studies over the last two decades. Cell therapy, a novel treatment modality in which therapeutic cells are introduced to the site of the injury to promote tissue regeneration, has opened up new possibilities for treating aneurysms. The healing response that ensues aneurysm embolization includes several cellular processes that can be targeted with cell therapy to prevent the aneurysm from recurring. Ten preclinical studies involving cell therapy to treat aneurysms were published between 1999 and 2014. In this review, we summarize the results of these studies and discuss advances, shortcomings, and the future of cell therapy for intracranial aneurysms.

Microsurgical clipping for recurrent aneurysms after initial endovascular coil embolization.

OBJECTIVE: Surgical treatment for recurrent lesions of embolized aneurysms is difficult and challenging for many neurosurgeons because intra-aneurysmal coil masses are sometimes scarred to the wall of the aneurysm or adherent to adjacent vital structures. To assess the efficacy and safety of surgical treatment without coil removal for recurrent aneurysms after previous coil embolization, we retrospectively studied clinical results, angiographic results, and complications in patients treated with additional microsurgical clipping. METHODS: From April 2003 to April 2013, 7 patients with recurrent previous embolized aneurysms underwent microsurgical treatment. RESULTS: This series included 1 man and 6 women receiving endovascular coiling as the first-line treatment. One patient's aneurysm was unruptured, whereas the other 6 were ruptured. The aneurysm locations were posterior communicating (n = 3), anterior communicating (n = 2), ophthalmic (n = 1), and posterior inferior cerebellar (n = 1). The initial sizes ranged from 3-11.5 mm in diameter (mean, 6.6 mm), and the aspect ratios were 1.2 to 3.4 (mean, 1.9). In these aneurysms, the initial coiling result was complete occlusion in 5 patients, and neck remnants in 2 patients. The mechanism underlying aneurysm recurrence was coil compaction in 3 aneurysms, aneurysm regrowth in 3 aneurysms, and fundal migration in 1 aneurysm. The median recurrence latency was 28.8 months (range, 0.7-115 months). Microsurgical clippings without coil removal were used in 6 patients; a parent artery occlusion under bypass protection was done in 1 case with a posterior inferior cerebellar aneurysm. Fenestrated clips in combination with another type of clip were successfully used for 4 of 6 patients who were treated with direct neck clipping. No postoperative morbidity was observed, and postoperative imaging studies revealed complete occlusion of the aneurysms in all cases. There were no recurrences of aneurysms during the follow-up period (mean, 44.7 months; range, 0.5-118 months). CONCLUSIONS: The microsurgical clipping without coil removal for recurrent lesions of embolized aneurysms is effective and safe when it is technically feasible. The tandem clipping in combination with a fenestrated clip is a crucial method for direct neck clipping without coil removal for previously coiled recurrent aneurysms. For unclippable lesions, a parent artery occlusion under bypass protection should be taken into consideration.

Microsurgical Treatment of Previously Coiled Intracranial Aneurysms: Systematic Review of the Literature.

OBJECTIVE: To assess indications, complications, clinical outcomes, and technical nuances of microsurgical treatment of previously coiled intracranial aneurysms. METHODS: A systematic review of the literature was performed using PubMed/MEDLINE and EMBASE databases from January 1990 to December 2013. English-language articles reporting on microsurgical treatment of previously coiled intracranial aneurysms were included. Articles that involved embolization materials other than coils were excluded. Data on aneurysm characteristics, indications for surgery, techniques, complications, angiographic obliteration rates, and clinical outcomes were collected. RESULTS: The literature review identified 29 articles reporting on microsurgical clipping of 375 previously coiled aneurysms. Of the aneurysms, 68% were small (<10 mm). Indications for clipping included the presence of a neck remnant (48%) and new aneurysmal growth (45%). Rebleeding before clipping was reported in 6% of cases. Coil extraction was performed in 13% of cases. The median time from initial coiling to clipping was 7 months. The angiographic cure rate was 93%, with morbidity and mortality of 9.8% and 3.6%, respectively. CONCLUSIONS: Microsurgical clipping of previously coiled aneurysms can result in high obliteration rates with relatively low morbidity and mortality in select cases. Considerations for microsurgical strategies include the presence of sufficient aneurysmal tissue for clip placement and the potential need for temporary occlusion or flow arrest. Coil extraction is not needed in most cases.

Microsurgical clipping of previously coiled intracranial aneurysms.

OBJECTIVE: Endovascular coiling techniques for the treatment of intracranial aneurysms have rapidly developed as an alternative option to surgical clipping. A distinct problem after endovascular coiling is the management of a residual aneurysm neck due to incomplete filling, compaction of coils or regrowth of the aneurysm. Treatment options in this situation include surgical clipping, re-coiling, stent implantation or observation. METHODS: From June 2006 to August 2011, 15 patients underwent surgical clipping of residual or recurrent aneurysms after previous endovascular treatment. The mean age of the patients was 50.6 years (range, 27-85 years). The mean interval between coiling and clipping was 76.5 weeks (range, 0-288 weeks). RESULTS: Thirteen patients revealed a regrowth of coiled aneurysms, and in 5 patients compaction of coils was present. Coil extrusion was observed in 9 patients intraoperatively. In case of coil obstruction at the aneurysmal neck during surgery, coils were partially or completely removed. In all cases complete occlusion of the aneurysms was surgically achieved. CONCLUSION: Coiled aneuryms with incomplete occlusion, coil compaction or regrowth of the aneurysmal neck can be successfully treated with microsurgical clipping. Coil extrusion was more often observed intraoperatively than expected. Complete occlusion of the aneurysm can be performed safely, even if loops of coils protrude into the aneurysmal neck. In these cases intraoperative removal of the coils enables secure closure of the aneurysm with a surgical clip.