Limitation of fenestrated clips during clipping of middle cerebral artery aneurysm: Technical note.

Background: The middle cerebral artery (MCA) is a common site of cerebral aneurysms and 82.6% occur at the bifurcation. When surgery is selected as a therapeutic option, it intends to clip the neck completely because if some remnant occurs, there exists the possibility of regrowth and bleeding in the short- or long-term. Methods: We analyzed one drawback of the fenestrated clips of Yasargil and Sugita types to occlude the neck totally at a specific point formed by the union of the fenestra with the blades, creating a triangular space where the aneurysm can protrude, giving place to a remnant that can lead to a future recurrence and rebleeding. We show two cases of ruptured MCA aneurysms in which a cross-clipping technique occluded a broad base and dysmorphic aneurysm using straight fenestrated clips. Results: In both cases (one using a Yasargil clip and the other with a Sugita clip), a small remnant was visualized when fluorescein videoangiography (FL-VAG) was used. In both cases, the small remnant was clipped with a 3 mm straight miniclip. Conclusion: We should be aware of this drawback when clipping aneurysms using fenestrated clips to ensure a complete obliteration of the aneurysm's neck.

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.

Presurgical selection of the ideal aneurysm clip by the use of a three-dimensional planning system.

Aneurysm occlusion rate after clipping is higher than after endovascular treatment. However, a certain percentage of incompletely clipped aneurysms remains. Presurgical selection of the proper aneurysm clips could potentially reduce the rate of incomplete clippings caused by inadequate clip geometry. The aim of the present study was to assess whether preoperative 3D image-based simulation allows for preoperative selection of a proper aneurysm clip for complete occlusion in individual cases. Patients harboring ruptured or unruptured cerebral aneurysms prior to surgical clipping were analyzed. CT angiography images were transferred to a 3D surgical-planning station (Dextroscope®) with imported models of 58 aneurysm clips. Intracranial vessels and aneurysms were segmented and the virtual aneurysm clips were placed at the aneurysm neck. Operating surgeons had information about the selected aneurysm clip, and patients underwent clipping. Intraoperative clip selection was documented and aneurysm occlusion rate was assessed by postoperative digital subtraction angiography. Nineteen patients were available for final analysis. In all patients, the most proximal clip at the aneurysm neck was the preselected clip. All aneurysms except one were fully occluded, as assessed by catheter angiography. One aneurysm had a small neck remnant that did not require secondary surgery and was occluded 15 months after surgery. 3D image-based preselection of a proper aneurysm clip can be translated to the operating room and avoids intraoperative clip selection. The associated occlusion rate of aneurysms is high.

Interrater and intrarater agreement superior for three-dimensional digital subtraction angiography (3D-DSA) over 2D-DSA classification for detecting remnants after intracranial aneurysm clipping, a GRRAS Reliability and Agreement Study.

BACKGROUND: Growing evidence suggests that three-dimensional digital subtraction angiography (3D-DSA) is superior to 2D-DSA in detection of intracranial aneurysm (IA) remnants after clipping. With a simple, practical quantitative scale proposed to measure maximal remnant dimension on 3D-DSA, this study provides a rigorous interrater and intrarater reliability and agreement study comparing this newly established scale with a commonly used (Sindou) 2D-DSA scale. METHOD: Records of 43 patients with clipped IAs harboring various sized remnants who underwent 2D- and 3D-DSA between 2012 and 2018 were evaluated. Using the 2D and 3D scales, six raters scored these remnants and repeated the scoring task 8 weeks later. Interrater and intrarater agreement for both grading schemes were calculated using kappa (κ) statistics. RESULTS: Interrater agreement was highly significant, yielding κ-values at 95% CI (p = 0.000) of 0.225 for the first [0.185; 0.265] and 0.368 s [0.328; 0.408] time points for 2D-DSA and values of 0.700 for the first [0.654; 0.745] and 0.776 s [0.729; 0.822] time points for 3D-DSA. Intrarater agreement demonstrated κ-values between 0.139 and 0.512 for 2D-DSA and between 0.487 and 0.813 for 3D-DSA scores. CONCLUSION: Interrater and intrarater agreement was minimal or weak for 2D-DSA scores, but strong for 3D-DSA scores. We propose that baseline 3D-DSA characterization may prove more reliable when categorizing clipped IA remnants for purposes of risk stratification and lifelong follow-up.

Value of 3-Dimensional Digital Subtraction Angiography for Detection and Classification of Intracranial Aneurysm Remnants After Clipping.

BACKGROUND: The current gold standard for evaluation of the surgical result after intracranial aneurysm (IA) clipping is two-dimensional (2D) digital subtraction angiography (DSA). While there is growing evidence that postoperative 3D-DSA is superior to 2D-DSA, there is a lack of data on intraoperative comparison. OBJECTIVE: To compare the diagnostic yield of detection of IA remnants in intra- and postoperative 3D-DSA, categorize the remnants based on 3D-DSA findings, and examine associations between missed 2D-DSA remnants and IA characteristics. METHODS: We evaluated 232 clipped IAs that were examined with intraoperative or postoperative 3D-DSA. Variables analyzed included patient demographics, IA and remnant distinguishing characteristics, and 2D- and 3D-DSA findings. Maximal IA remnant size detected by 3D-DSA was measured using a 3-point scale of 2-mm increments. RESULTS: Although 3D-DSA detected all clipped IA remnants, 2D-DSA missed 30.4% (7 of 23) and 38.9% (14 of 36) clipped IA remnants in intraoperative and postoperative imaging, respectively (95% CI: 30 [ 12, 49] %; P-value .023 and 39 [23, 55] %; P-value = <.001), and more often missed grade 1 (< 2 mm) clipped remnants (odds ratio [95% CI]: 4.3 [1.6, 12.7], P-value .005). CONCLUSION: Compared with 2D-DSA, 3D-DSA achieves a better diagnostic yield in the evaluation of clipped IA. Our proposed method to grade 3D-DSA remnants proved to be simple and practical. Especially small IA remnants have a high risk to be missed in 2D-DSA. We advocate routine use of either intraoperative or postoperative 3D-DSA as a baseline for lifelong follow-up of clipped IA.

Frequency and risk factors for postoperative aneurysm residual after microsurgical clipping.

OBJECTIVE: Aneurysm residuals after clipping are a well-known problem, but the course of aneurysm remnants in follow-up is not well studied. No standards or follow-up guidelines exist for treatment of aneurysm remnants. The aim of this study was to evaluate the risk factors for postoperative aneurysm remnants and their changes during follow-up. METHODS: We performed a retrospective analysis of 666 aneurysms treated via clipping in our hospital from 2006 to 2016. Postoperative and follow-up angiographic data were analyzed for aneurysm remnants and regrowth. Clinical parameters and aneurysm-specific characteristics were correlated with radiological results. RESULTS: The frequency of aneurysm residuals was 12% (78/666). Aneurysms located in the middle cerebral artery (p = 0.02) showed a significantly lower risk for incomplete aneurysm occlusion. Larger aneurysms with a diameter of 11-25 mm (p = 0.005) showed a significantly higher risk for incomplete aneurysm occlusion. Five patients underwent re-clipping during the same hospital stay. Remnants were stratified based on morphological characteristics into "dog ears" (n = 60) and "broad based" (n = 13). The majority of the "dog ears" stayed stable, decreased in size, or vanished during follow-up. Broad-based remnants showed a higher risk of regrowth. CONCLUSIONS: A middle cerebral artery location seems to lower the risk for the incomplete clip occlusion of an aneurysm. Greater aneurysm size (11-25 mm) is associated with a postoperative aneurysm remnant. The majority of "dog-ear" remnants appear to remain stable during follow-up. In these cases, unnecessarily frequent angiographic checks could be avoided. By contrast, broad-based residuals show a higher risk of regrowth that requires close imaging controls if retreatment cannot be performed immediately.

Rescue endovascular treatment for rapid regrowth of aneurysm remnant on middle cerebral artery trunk after unsuccessful surgical clipping in patients with a ruptured cerebral aneurysm: A report of two cases.

We report two rare cases treated with coiling after rapid regrowth (within a month) of an aneurysm remnant on the middle cerebral artery (MCA) trunk after incomplete surgical clipping. The first case, a 47-year-old man with subarachonoid hemorrhage (SAH) (Hunt-Hess grade II, Fisher grade III) underwent clipping of a ruptured saccular aneurysm with a wide neck on the right early frontal branch arising from the MCA trunk. Incomplete clipping with a 1 mm sized remnant neck was performed to avoid sacrificing the lenticulostriate artery. In a follow-up cerebral angiogram on postoperative day 30, a rapid regrowth of the aneurysm remnant was observed, and on that day, complete obliteration was obtained by rescue endovascular treatment. The second case, a 48-year-old healthy woman with SAH (Hunt-Hess grade II, Fisher grade III) underwent clipping of an anteroposteriorly projecting bilobulated aneurysm on the left M1. Incomplete clipping with a minimal remnant neck was performed. In follow-up digital subtraction angiogram on postoperative day 30, a rapid regrowth of an aneurysm remnant involving only a part of the initial aneurysm near the neck was observed, and on that day, complete obliteration was obtained by rescue coiling. These patients were both discharged without any neurological deficits.

Intraoperative fluorescein video angiography in intracranial aneurysm surgery: single-center, observational cohort study.

The aim of this study was to compare the incidence of postoperative, surgery-related complications in patients where fluorescein video angiography (FL-VA) was performed with those operated without intraoperative verification. This is an observational cohort study including 97 patients who were selected for microsurgical clipping due to intracranial aneurysm. First 52 patients enrolled in the study were operated prior to introduction of fluorescein fluorescence in our surgical workflow. These patients were considered as controls. The study group consisted of 45 consecutive patients operated with the use of fluorescein video angiography and by the same surgical team. Outcomes in both groups were compared using non-parametric test (Mann-Whitney U). Intraoperative fluorescein video angiography revealed aneurysm remnant or inadvertent vessel occlusion in 17.8% of patients. Following clip reposition, a repeated FL-VA was performed to confirm restoration of blood flow and/or complete aneurysm obliteration. Intraoperative findings were later confirmed using computed tomography angiography (CTA). None of the patients in our study group developed surgery-related complications; whereas in the control group, aneurysm remnant was discovered in 7.7%, brain ischemia in 9.6% and both of the latter in 5.8% of patients. Difference in treatment-related outcome was statistically significant (p < 0.05). Intraoperative fluorescein video angiography successfully identified aneurysm residual and adjacent artery occlusion leading to excellent outcome following clip reposition.

Woven Endobridge (WEB) Device as a Retreatment Strategy After Unsuccessful Surgical Clipping.

BACKGROUND: Surgical clipping of intracranial aneurysms is typically robust and durable. However, residual aneurysmal components may be seen after clipping. Furthermore, there may be occasional aneurysmal recurrence. These factors are both clinically relevant because subarachnoid hemorrhage after clipping is a rare but important event. The rationale for any treatment is to substantially decrease the future risk of hemorrhage. Small series have shown coiling as a retreatment strategy after unsuccessful clipping, but none has explored the feasibility of Woven Endobridge (WEB) implantation. CASE DESCRIPTION: We examined the feasibility of WEB implantation as second-line treatment for wide-necked residual aneurysms after unsuccessful clipping. We also recorded the safety and efficacy in this small series of 6 patients. To determine safety, we measured the modified Rankin Scale score before and after the procedure, and at 2 later time points (mean follow-up, 5 months and 15 months). To determine efficacy, we obtained radiographic aneurysm occlusion outcomes (including WEB Occlusion Scale) at these 2 time points. Four middle cerebral artery and 2 anterior communicating artery complex aneurysms were treated with WEB implantation, showing feasibility in 6/6 cases (100%). Follow-up at 15 months showed no change from preprocedural modified Rankin Scale score and there were no other complications. There was adequate occlusion in 5/6 cases (83%). CONCLUSIONS: WEB implantation provided a feasible option in this challenging retreatment scenario. This is a small series and prospective data are required to make outcome inferences for this population. Nonetheless, we observed no complications and high adequate occlusion rates.

Identifying Predictors for Aneurysm Remnants After Clipping by Morphometric Analysis and Proposal of a Novel Risk Score.

OBJECTIVE: Although the risk of aneurysm remnants after microsurgical clipping is generally low, complete aneurysm occlusion is not always guaranteed. We performed a morphometric analysis of intracranial aneurysms to identify predictors for aneurysm remnants and to propose a novel risk score. METHODS: This is a retrospective, single-center analysis of consecutive patients with ruptured and unruptured aneurysms who underwent microsurgical clipping and postoperative digital subtraction angiography between 2010 and 2018. Based on preoperative rotational angiography, distinct morphologic aneurysm characteristics were determined and correlated with postoperative angiographic results. Factors predictive in the univariate and multivariate analyses were determined to establish a risk score for postoperative remnants after aneurysm clipping. RESULTS: Among 140 patients with 166 clipped aneurysms, aneurysm remnants were present in 19.9%. In the multivariate analysis, ruptured aneurysm status (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.7-36; P < 0.01) and increased aspect ratio (OR, 1.9; 95% CI, 1.0-4.0; P = 0.07) were associated with postoperative aneurysm remnants. Anterior communicating artery location (P = 0.02), internal carotid artery location (P = 0.06), increased aneurysm inclination angle (P < 0.01), and irregular aneurysm shape (P = 0.07) were further predictors for aneurysm remnants in the univariate analysis. These factors were weighted and included into a risk sum score for postoperative aneurysm remnants (range, 0-8 points), which performed with good accuracy (area under the curve = 0.807). CONCLUSIONS: After external validation of the proposed risk score, it could help identify cases requiring angiographic control after aneurysm surgery.

Spontaneous Regression of Aneurysm Remnant after Incomplete Surgical Clipping in a Patient with Ruptured Cerebral Aneurysm.

Cases of spontaneous regression of cerebral aneurysm remnant after incomplete surgical clipping have been rarely reported. This paper reports the regression of an aneurysm remnant after incomplete surgical clipping during postsurgical follow-up. A 50-year-old male presented with subarachnoid hemorrhage because of rupture of an anterior communicating artery aneurysm. An emergency clipping of the aneurysm was performed. A cerebral angiography, which was performed two weeks postoperatively, revealed an aneurysm remnant. The patient refused additional treatment and was discharged without apparent neurological deficit. One-year follow up cerebral angiography demonstrated a partially regressed aneurysm remnant.

Spontaneous Regression of Aneurysm Remnant after Incomplete Surgical Clipping in a Patient with Ruptured Cerebral Aneurysm

Cases of spontaneous regression of cerebral aneurysm remnant after incomplete surgical clipping have been rarely reported. This paper reports the regression of an aneurysm remnant after incomplete surgical clipping during postsurgical follow-up. A 50-year-old male presented with subarachnoid hemorrhage because of rupture of an anterior communicating artery aneurysm. An emergency clipping of the aneurysm was performed. A cerebral angiography, which was performed two weeks postoperatively, revealed an aneurysm remnant. The patient refused additional treatment and was discharged without apparent neurological deficit. One-year follow up cerebral angiography demonstrated a partially regressed aneurysm remnant.

Role of Multislice Computerized Tomographic Angiography after Clip Placement in Aneurysm Patients Based on Comparison with Three Dimensional Digital Subtraction Angiography

OBJECTIVE: We evaluated the accuracy of multislice computerized tomographic angiography (MCTA) in the postoperative evaluation of clipped aneurysms by comparising it with three dimensional digital subtraction angiography (3D-DSA). METHODS: Between May 2004 and September 2006, we included patients with ruptured cerebral aneurysm of the anterior circulation that was surgically clipped and evaluated by both postoperative MCTA and postoperative 3D-DSA. We measured the diagnostic performance and calculated the sensitivity and specificity of postoperative MCTA compared to 3D-DSA in the detection of aneurysm remnants. RESULTS: A total of 11 neck remnants among the 92 clipped aneurysms (11.9%) were confirmed by 3D-DSA. According to Sindou's classification of aneurysm remnants, 8.7% of clipped aneurysms (8/92) had only neck remnant on 3D-DSA and 3.2% (3/92 aneurysms) had residuum of the neck and sac on 3D-DSA. There were 12 (13.04%) equivocal cases that were difficult to interpret based on the postoperative MCTA. The reasons for the equivocal cases included multiple clips (6 cases, 50.0%), beam-hardening effect (4 cases, 33.3%), motion artifact (1 case, 8.3%), fenestrated clip (1 case, 8.3%) and other combined causes. The sensitivity and specificity of the postoperative MCTA was 81.8% and 88.9%, respectively, by ROC curve (p=0.000). CONCLUSION: MCTA is an accurate noninvasive imaging method used for the assessment of clipped aneurysms in the anterior circulation. If the image quality of postoperative MCTA is good quality and the patient has been treated with a single titanium clip, except a fenestrated clip, the absence of an aneurysm remnant can be diagnosed by MCTA alone and the need for postoperative DSA can be reduced in a large percentage of cases.

Role of Three-dimensional Computed Tomography Angiography in the Follow-up of Patients with Aneurysm Clips

OBJECTIVE: The purpose of this study is to assess the usefulness of three-dimensional computed tomography angiography (3D-CTA) as a postoperative follow-up examination after intracranial aneurysms have been clipped. METHODS: Between January 2002 and June 2005, 522 consecutive patients received treatment for intracranial aneurysms. A retrospective analysis of 310 patients with postoperative 3D-CTAs was performed to evaluate aneurysmal remnants and de novo aneurysms. This study was conducted in 271 patients with at least immediate and 6-month routine 3D-CTAs for postoperative clipped aneurysm and 39 patients with 3D-CTAs for clipped aneurysm before 2002 when there was no 3D-CTA in our hospital. RESULTS: Eight patients had abnormal CT angiographic findings. Aneurysm remnants were revealed in 4 patients and de novo aneurysms were discovered in 5 patients. Two patients were found at the postoperative 6-month 3D-CTA performed routinely. In 1 patient, the aneurysm was demonstrated on the way to the examination of syncope. In 2 patients, the author recommended 3D-CTA although there was no symptom because the patients had visited our institute long time ago (5.1, 4.5 years). Of the 8 patients, 2 remnants and 1 de novo aneurysm were treated by endovascular treatment. Three de novo aneurysms at the middle cerebral artery and 1 pericallosal artery aneurysm were treated by direct clipping because these aneurysms were not suitable for the endovascular treatment in point of anatomical configuration. One patient with both remnant and de novo aneurysm was treated conservatively. CONCLUSION: 3D-CTA is an available, non-invasive diagnostic tool for the postoperative follow-up examination of aneurysmal state in patients after clipping.