Unruptured Paraclinoid Aneurysms Research Articles

Risk Factors for Visual Impairments in Patients with Unruptured Intradural Paraclinoid Aneurysms Treated by Neck Clipping without Bypass Surgery

Although paraclinoid aneurysms are now frequently referred for endovascular treatment, the durability of obliteration is still to be determined. Therefore, direct surgery for paraclinoid aneurysms still remains indispensable. The present study aimed to evaluate the risk factors for the visual impairments in patients with unruptured intradural paraclinoid aneurysms. The data of 133 patients with 136 aneurysms treated by neck clipping without bypass surgery was evaluated. Visual impairments included decreased visual acuity and visual field defect. The aneurysm was classified into superior projecting aneurysm, ventral projecting aneurysm, and carotid cave aneurysm. Plug-in method was defined as filling interspace, which was formed between the internal carotid artery and the sutured dura in case of detachment of the dural ring. Postoperative new visual impairments were observed in 30 aneurysms (22%). During the follow-up period (median, 600 days), postoperative new visual impairments continued in 23 aneurysms (17%). Multivariate analysis showed that carotid cave location and plug-in method were related to new visual impairments at 30 days (odds ratio [OR], 2.6; 95% confidence interval [CI] 1.1-6.1; P= 0.031 and OR, 4.1; 95% CI 1.4-12; P= 0.008) and at 6 months (OR, 4.1; 95% CI 1.5-11; P= 0.005 and OR, 3.3; 95% CI 1.1-11; P= 0.045). The present study showed that carotid cave location and plug-in method during dural closures were related to postoperative continued visual impairments. Neurosurgeons should carefully consider the surgical indication for unruptured carotid cave aneurysms and avoid plug-in methods.

Predictive Factors for the Occurrence of Visual and Ischemic Complications After Open Surgery for Paraclinoid Aneurysms of the Internal Carotid Artery.

To investigate the predictive factors for visual and ischemic complications after open surgery for paraclinoid aneurysms of the internal carotid artery (ICA). Thirty-eight consecutive patients with unruptured paraclinoid aneurysms of ICA operated on between 2009 and 2013 were included in this study. The male:female ratio was 6:32 and the ages ranged from 33 to 81 (mean: 60 ± 2). Twenty cases were asymptomatic and 18 had ophthalmological symptoms. The sizes of the aneurysms ranged from 2 to 35 mm (mean: 10.6 ± 9 mm). Twenty-three patients were treated by clipping and 15 by trapping with bypass (high-flow bypass in 11, and low-flow in 4). Twenty-four patients underwent removal of the anterior clinoid process. Among them, 8 underwent en bloc anterior clinoidectomy with a high-speed drill, and 16 had piecemeal excision with a microrongeur or ultrasonic bone curette. Intraoperative monitoring was performed using motor-evoked potentials (MEP) and visual-evoked potentials (VEP) in 27 and 15 cases, respectively. Complete obliteration of the aneurysm was achieved in 37 cases (97.4 %). The patency rate of bypass was 100 %. Postoperative worsening of visual acuity, including one case of blindness, was observed in six cases (11 %). Worsening of visual field defects occurred in 14 cases (38 %), but 10 of them were transient. Transient oculomotor nerve palsy occurred in six cases (15 %). Postoperative stroke was detected by diffusion-weighted imaging (DWI) in five cases (13 %), four of which were symptomatic. Statistical analysis showed that piecemeal anterior clinoidectomy was significantly safer than en bloc removal in preserving visual function. Trapping with high-flow bypass had a significantly greater risk of postoperative stroke than direct clipping. Intraoperative VEP monitoring might be useful for preventing postoperative worsening of visual function. Two-stage treatment with bypass and endovascular trapping might be safer than single-stage trapping alone.

Endovascular Treatment of Unruptured Paraclinoid Aneurysms: Single-Center Experience with 400 Cases and Literature Review.

Paraclinoid aneurysms have been increasingly treated endovascularly. The natural history of these aneurysms has gradually been elucidated. The purpose of this study was to assess the safety and efficacy of endovascular treatment for these aneurysms. We performed a retrospective review of 377 patients with 400 paraclinoid aneurysms treated between January 2006 and December 2012. Their clinical records, endovascular reports, and radiologic and clinical outcomes were analyzed. Because aneurysms ≥7 mm are at higher risk of rupture, we classified aneurysms as small (<7 mm) or large (≥7 mm). Overall, 115 of the 400 aneurysms (28.8%) were large (≥7 mm). Thromboembolic complications were found significantly more often with large aneurysms than with small ones (7.4% vs 1.0%, P = .001). Hemorrhagic complications were found only with small aneurysms (0.7%). The 6-month morbidity rates were similar for small (1.0%) and large (0.8%) aneurysms. Immediate angiographic outcomes were similar (P = .37), whereas recurrences and retreatment occurred more frequently with large aneurysms (P = .001 and P = .007, respectively). Multivariate analysis showed that aneurysm size was the only independent predictor for recurrence (P = .005). Most recurrences (81%) were detected by scheduled angiography at 6 months. Aneurysm size influenced the type of complication (thromboembolic or hemorrhagic) and the recurrence rate. Given the approximately 1% annual rupture rate for aneurysms ≥7 mm, analysis of our data supports the rationale of using prophylactic endovascular treatment for unruptured paraclinoid aneurysms ≥7 mm.

Localization and Treatment of Unruptured Paraclinoid Aneurysms: A Proton Density MRI-based Study.

ObjectiveThe purpose of this study was to evaluate the usefulness of proton density magnetic resonance (PD MR) imaging for localization of paraclinoid internal carotid artery aneurysms.Materials and MethodsFrom April 2014 to April 2015, 76 unruptured paraclinoid aneurysms in 66 patients were evaluated using PD MR and angiography (CT/MR angiography or digital subtraction angiography). The locations (extradural, transdural, intradural) in relation to the distal dural ring (DDR) and projection (superior, inferior/posterior, medial, lateral) of the aneurysms were assessed and compared.ResultsThe most common location of paraclinoid aneurysms was extradural (n = 48, 63.2%), followed by intradural (n = 18, 23.7%), and transdural (n = 10, 13.2%). In the medial projection group (n = 49, 64.5%), 31 were extradural (63.3%), 5 were transdural (10.2%), and 13 were intradural (26.5%). In the inferior/posterior projection group (n = 19, 25.0%), there were 14 extradural (73.7%), 4 transdural (21.0%), and 1 intradural (5.3%). In the superior (n = 4, 5.3%)/lateral (n = 4, 5.3%) projection groups, there were 0/3 extradural (0/75.0%), 1/0 transdural (25.0/0%), and 3/1 intradural (75.0/25.0%).ConclusionPD MR showed sufficient contrast difference to distinguish paraclinoid aneurysms from surrounding dural structures.

Management strategy of surgical and endovascular treatment of unruptured paraclinoid aneurysms based on the location of aneurysms

ObjectiveAdvances in endovascular treatment (EVT) have greatly improved the treatment outcomes of paraclinoid aneurysms. However, EVT had the shortcoming of durability and thromboembolic complications. As well, surgical treatment of paraclinoid aneurysms is still challenging due to the complexity of adjacent structures. The objective of this study is to report our experience with a combined surgical and endovascular treatment of unruptured paraclinoid aneurysms based on the location of aneurysms. MethodsA retrospective review was conducted of 185 cases of unruptured paraclinoid aneurysms that underwent surgical or endovascular treatment between September 2008 and August 2012. Thirty-one aneurysms (16.8%) were treated by microsurgery and 154 (83.2%) were treated by EVT. Fifty aneurysms (27.0%) were classified to the dorsal group and 135 (73%) were classified to the non-dorsal group. ResultsTwenty of 50 dorsal group aneurysms (40%) were treated by microsurgery while 124 of 135 non-dorsal group aneurysms (91.9%) underwent an EVT. The rate of complete occlusion was 96.8% in surgical series and 60.4% in EVT (P<0.001). Recanalization occurred in 9 aneurysms (5.8%) of EVT and 1 aneurysm (3.2%) of surgical series (P=0.360). In non-dorsal group, transient complications (10 aneurysms (5.4%), P=0.018) and morbidity at last visiting (6 aneurysms (3.2%), P=0.021) were more present in surgically treated cases rather than in EVT cases. Diplopia and visual field defect occurred in the non-dorsal group only; in 2 of 11 surgical cases (18.2%) and in 1 of 124 EVT series (0.8%) (P=0.017). The overall rate of excellent or good clinical outcomes (Glasgow outcome scale 5 or 4) was 98.9%. ConclusionEVT is a safe and effective treatment for the non-dorsal group. Based on angiographic and clinical aspects, microsurgical clipping has prior efficacy with better outcomes in the dorsal group under proper individualized selection.

Angiographic characteristics of ruptured paraclinoid aneurysms: risk factors for rupture

The diagnosis and treatment of unruptured paraclinoid aneurysms has been increasing with the recent advent of diagnostic tools and less invasive endovascular therapeutic options. Considering the low incidence of rupture, investigation of the characteristics of ruptured paraclinoid aneurysm is important to predict rupture risk of the paraclinoid aneurysms. The objective of this study is to evaluate probable factors for rupture by analyzing the characteristics of ruptured paraclinoid aneurysms. A total of 2,276 aneurysms (1,419 ruptured and 857 unruptured) were diagnosed and treated endovascularly or microsurgically between 2001 and 2011. Among them, 265 were paraclinoid aneurysms, of which 37 were ruptured. Removing 12 blister-like aneurysms, 25 ruptured and 228 unruptured saccular aneurysms were included and the medical records and radiological images were retrospectively analyzed. Of 25 aneurysms, 16 (64.0%) were located in the superior direction. Five were inferior located lesions (20%) and four were medially located lesions (16.0%). Laterally located lesions were not found. The mean size of aneurysms was 9.4 ± 5.6 mm. Ten aneurysms (40.0%) were ≥ 10 mm in size. Thirteen aneurysms (52.0%) were lobulated. The superiorly located aneurysms were larger than the other aneurysms (10.3 ± 5.8 mm vs. 7.7 ± 4.9 mm) and more frequently lobulated (ten of 16 vs. three of nine). In a comparative analysis, the ruptured aneurysms were located more in the superior direction compared with unruptured aneurysms (64 vs. 23.2%, p < 0.0001). Large aneurysms (36.0 vs. 7.9%, p < 0.0001), longer fundus diameter (mean 9.4 ± 5.6 vs. 4.8 ± 3.3 mm, p = 0.001), dome-to-neck ratio (mean 1.8 ± 0.9 vs. 1.2 ± 0.5, p < 0.0001), and lobulated shape aneurysms were more likely to be ruptured aneurysms (13 of 25 ruptured aneurysms, 52.0%, p = 0.001). Rupture risk of the paraclinoid aneurysm is very low. However, superiorly located paraclinoid aneurysms appear more likely to rupture than other locations. Angiographically, more conservative indication for the treatment of paraclinoid aneurysm should be recommended except for superior located lesions.

Long-term follow-up of intra-aneurysmal coil embolization for unruptured paraclinoid aneurysms

Objectives: The selection of therapeutic modalities, including endovascular coil embolization and surgical clipping, for management of unruptured paraclinoid aneurysms, remains controversial. Detailed long-term outcome data for endovascular coil embolization of unruptured paraclinoid aneurysms are still lacking. Thus, we evaluated the safety and efficacy of coil embolization of unruptured paraclinoid aneurysms.Methods: From January 1998 to July 2010, 138 patients underwent endovascular coiling for 140 unruptured paraclinoid aneurysms. Their medical records and radiologic images were reviewed retrospectively.Results: Complications occurred in 5·7% of 140 procedures and the morbidity rate was 0·7%. Of the 140 unruptured paraclinoid aneurysms, a total of 111 aneurysms underwent follow-up imaging evaluation at 2 years or more, or showing reopening on imaging studies within 2 years (65·6±37·2 months). Multivariate analysis revealed two predictors for reopening of the aneurysms: a maximum diameter of aneurysms and a dome/neck ratio of aneurysms (P<0·05). Reopening rates of aneurysms with maximum sizes of <8, 8–10, and >10 mm were 1%, 25%, and 75%, respectively. Reopening rates were significantly different among the three groups (P<0·05). In aneurysms with a maximum diameter of 8–10 mm, there was a significant difference of dome/neck ratios between the presence and absence of reopened aneurysms (P<0·05).Discussion: The results indicate that endovascular coil embolization is a safe and effective treatment modality in selected patients with unruptured paraclinoid aneurysms. Consideration of the aneurysm size and the dome/neck ratio could assist in the selection of therapeutic modalities for these aneurysms.

Coiling for Paraclinoid Aneurysms: Time to Make Way for Flow Diverters?

Paraclinoid aneurysms represent challenging lesions for which endovascular techniques have gained widespread application in their treatment. A new endovascular strategy, flow diversion, is gaining importance in the treatment of these aneurysms. Before embracing flow diversion in larger numbers of patients with paraclinoid aneurysms, it is important to know the safety and efficacy of "traditional" endovascular methods for these aneurysms. We review complications and outcomes of patients with unruptured paraclinoid aneurysms treated with coils, with or without balloon and stent assistance, over the past 12 years at our institution. A retrospective review of 118 patients with 126 unruptured paraclinoid aneurysms, treated between 1999 and 2010, was performed. Clinical records, endovascular reports, angiographic results, and clinical outcomes were reviewed and analyzed. Fifty-nine percent of aneurysms were carotid-ophthalmic, 27% were hypophyseal, 9% were posterior carotid wall, 3% were carotid cave, and 2% were transitional. Twenty-one percent of aneurysms were symptomatic, and 3% were recurrent aneurysms after previous treatment. Fifty (40%) were treated with balloon assistance and 18 (14%) with stent assistance. Technical complications causing permanent morbidity occurred in 1 patient (0.8%), while early clinical complications causing transient morbidity occurred in 5 (4%) patients. Complete occlusion was achieved in 40% of aneurysms immediately after treatment and in 66 (62%) aneurysms during follow-up (mean 31.9 ± 28.4 months). Recurrences occurred in 18 patients (17%) and 10 (9%) patients were retreated. Clinical outcome was good in 95% and poor in 5% of the 107 patients with follow-up (mean 37.0 ± 33.7 months). Only in 1 patient was poor outcome related to the endovascular procedure. Transient ischemic attacks occurred in 4% of patients. No cases of rebleeding were observed during follow-up. Modern endovascular coil treatment of unruptured paraclinoid aneurysms appears safe, with satisfactory, although not ideal, rates of complete occlusion. The introduction of flow diverters will probably increase the rate of complete angiographic occlusion, but this must be achieved with low complication rates.

Optic Strut as a Radiographic Landmark in Evaluating Neck Location of a Paraclinoid Aneurysm

The optic strut (OS) is a candidate landmark in computed tomographic (CT) angiographic scans for the discrimination of intradural and extradural/intracavernous aneurysms involving the paraclinoid segment of the internal carotid artery. The goal of this study is to examine and confirm the qualifications of the OS as a landmark in CT angiographic scans for the preoperative evaluation of aneurysms in this region. Seventeen consecutive patients with 18 unruptured paraclinoid aneurysms who underwent preoperative CT angiography scans and direct surgery between 1998 and 2005 were evaluated retrospectively. We focused on the relationships of the necks of aneurysms to the OS in CT angiographic scans and that of the necks to proximal dural rings during intraoperative examinations. Direct surgery revealed that 14 aneurysms, the necks of which were distal to the OS on CT angiographic scans, arose distal to the proximal dural rings. All aneurysms were clipped, except one exhibiting calcification of the neck. Three aneurysms, for which the neck was proximal to the OS on CT angiographic scans, revealed only a portion or nothing of their domes instead of their necks through the proximal dural rings after dissection of the distal dural rings. Dome coating with fibrin glue and a piece of muscle tissue or mere exploration was performed. Another aneurysm, of which the neck straddled the OS on CT angiographic scans, was found to arise across the proximal dural ring. Clipping of the neck was performed after dissection of the proximal dural ring. Of the source images of CT angiographic scans, the axial images were the most useful in evaluating the relationship of the neck of an aneurysm to the OS. On CT angiographic scans, the OS is a precise identification of the proximal dural ring that forms the superior border of the cavernous sinus. The aneurysms whose necks arise obviously distal to the OS on CT angiographic scans are able to be clipped without dissection of the proximal dural ring.

Postoperative vasospasm of unruptured paraclinoid carotid aneurysms: analysis of 30 cases

This study was conducted to determine the incidence, severity, and causes of delayed vasospasm after clipping of unruptured paraclinoid aneurysms of the internal carotid artery (ICA). A retrospective analysis was made of 30 patients, who underwent clipping of unruptured paraclinoid aneurysms in our institution between 1991 and 1998. We compared angiograms before and after operation and classified them into two groups: vasospasm group and non-vasospasm group. Eleven variables were assessed as to their relationship to delayed vasospasm. There were 9 patients (30%) in the vasospasm group, of which 3 patients (10%) were clinically symptomatic. For all symptomatic patients, aggressive treatment, including triple-H therapy, was conducted with good outcome. The number of clips used (p<0.04) and temporary occlusion of the ICA (p<0.005) were statistically significant factors associated with the incidence of vasospasm. It is suggested that mechanical stimulation to the vascular wall of the ICA is responsible for causing spasm in addition to intraoperative bleeding around the dural ring.

Endovascular treatment of paraclinoid aneurysms: experience with 73 patients.

Aneurysms arising from the internal carotid artery in close relation to the clinoid process have been called paraclinoid aneurysms. The surgical management of these aneurysms poses technical challenges, and such patients are frequently referred for endovascular treatment. We reviewed our experience with endovascular coil embolization of paraclinoid aneurysms to evaluate the safety and efficacy of this treatment modality. From December 1993 to May 2002, 70 patients underwent endovascular procedures with detachable coils for 73 paraclinoid aneurysms (8 ruptured, 65 unruptured) at the University of Pittsburgh Medical Center and the University of Texas Southwestern Medical Center. A retrospective review of the medical records, outpatient charts, and operative reports was performed. Angiographic outcome was determined at the end of each procedure and by review of follow-up angiograms. Clinical assessments and outcomes are reported according to the Glasgow Outcome Scale (GOS). Immediate angiographic outcomes for 73 paraclinoid aneurysms demonstrated complete occlusion in 53 (72.6%), near-complete occlusion in 6 (8.2%), and partial occlusion in 14 (19.2%). Nine aneurysms required more than one coiling session to complete treatment; 8 of these aneurysms required two sessions and 1 required four, for a total of 84 endovascular procedures. Follow-up angiograms could be obtained in 49 patients with 52 paraclinoid aneurysms. During the follow-up period, 6 aneurysms demonstrating partial occlusion and 3 demonstrating near-complete occlusion showed spontaneous progression of thrombosis to complete occlusion. Twelve aneurysms initially demonstrating complete occlusion (5 aneurysms), near-complete occlusion (3 aneurysms), or partial occlusion (4 aneurysms) showed coil compaction requiring retreatment. Of these 12 aneurysms that demonstrated coil compaction, 3 were treated with surgery and 9 with coil repacking. The final angiographic outcomes, determined on the last available follow-up angiograms of 49 aneurysms, excluding 3 surgically clipped aneurysms, showed complete occlusion in 43 (87.8%), near-complete occlusion in 3 (6.1%), and partial occlusion in 3 (6.1%). The angiographic follow-up period ranged from 4 to 54 months (mean, 13.9 mo). Morbidity and mortality rates related to 84 endovascular procedures were 8.3 and 0%, respectively. There were no recurrent or new subarachnoid hemorrhages in 63 patients in whom clinical follow-up could be performed during a mean clinical follow-up period of 14.4 months. The final clinical outcomes demonstrated a GOS score of 5 (good recovery) in 56 patients (88.9%), a GOS score of 4 (moderate disability) in 2 (3.2%), and a GOS score of 3 (severe disability) in 1 (1.6%). Four patients (6.3%) died of unrelated causes. The average period of hospitalization was 17.8 days in patients with acutely ruptured aneurysms and 3.5 days in patients with unruptured or retreated aneurysms. The results of this study indicate that endovascular treatment is a safe and effective therapeutic alternative in ruptured and unruptured paraclinoid aneurysms. The endovascular treatment may also confer a positive impact in terms of the length of hospital stay.