Late angiographic follow-up review of surgically treated aneurysms

Treatment of Recurrent Intracranial Aneurysms After Neck Clipping: Novel Classification Scheme and Management Strategies

BACKGROUND

Recurrent aneurysms after initial clipping have been discussed as an important issue in the surgical management of aneurysm.

OBJECTIVE

To report our experience with recurrent cerebral aneurysms after neck clipping and to discuss classification and recommended management.

METHODS

Aneurysm treatments from a single institution over a 20-year period were retrospectively reviewed. Twenty-three recurrent aneurysms in 23 patients were managed during the study period. Recurrent aneurysms were classified using the concepts of closure line and closure plane, as follows. Type 1: neck situated in an almost different site from the previous clip. Type 2: existing closure plane and reconstructive closure plane are almost the same. Type 3: existing closure plane and reconstructive closure plane cross (type 3a); in rare cases, the existing closure line is sufficiently distant from the neck (type 3b). Type 4: no reconstructive closure line is identifiable.

RESULTS

Nine patients presented with subarachnoid hemorrhage at recurrence. The mean interval to recurrence was 15.0 years. Management comprised clipping with elective subsequent old-clip removal (n = 7), clipping with preceding old-clip removal (n = 2), bypass occlusion (n = 1), coating (n = 1), combined surgery (n = 1), endovascular surgery (n = 4), and observation (n = 3). Therapeutic intervention was not indicated in 4 patients. Types 3a and 4 required more complex surgical procedures or coil embolization. Procedural complications were observed in 2 patients.

CONCLUSION

A small but definite propensity toward recurrence after neck clipping exists, and most recurrent aneurysms require some form of retreatment. The novel classification scheme may provide conceptual clarity and therapeutic guidance for decision making.

Risk of de novo aneurysm formation in patients with a prior diagnosis of ruptured or unruptured aneurysm: systematic review and meta-analysis

OBJECTIVE

De novo aneurysms are rare entities periodically discovered during follow-up imaging. Little is known regarding the frequency with which these lesions form or the time course. This systematic review and meta-analysis was undertaken to estimate the incidence of de novo aneurysms and to determine risk factors for aneurysm formation.

METHODS

The authors searched multiple databases for studies of patients with unruptured and ruptured aneurysms describing the rate of de novo aneurysm formation. The primary outcome was incidence of de novo aneurysm formation. A meta-analysis was performed using a random-effects model. The authors examined the associations of multiple aneurysms, prior subarachnoid hemorrhage, smoking, sex, age at presentation, and hypertension with de novo aneurysm formation.

RESULTS

The meta-analysis included 14,968 aneurysm patients who received imaging follow-up from 35 studies. The overall incidence of de novo aneurysm formation was 2% (95% CI 2%-3%) over a mean follow-up time of 8.3 years. The estimated incidence density was 0.3%/patient-year. There was no statistically significant difference in rates of de novo aneurysm formation between patients who had ruptured aneurysms and those with unruptured aneurysms. In 8 studies, 11.2% of de novo aneurysms were found in patients with ≤ 5 years of follow-up and 88.8% were found at > 5 years. The mean time to rupture for de novo aneurysms was 10 years.

CONCLUSIONS

This systematic review demonstrates that formation of de novo aneurysms is rare. Overall, routine screening for de novo aneurysms is likely to be of low yield and could be performed at time intervals of at least 5 to 10 years.

Universal fluorescence module for intraoperative fluorescein angiography-a technical report

BACKGROUND

Even in specialized centers, suboptimal aneurysm clipping can be as high as 12%. Intraoperative fluorescence angiography with indocyanine green and, more recently, fluorescein sodium have been shown to be a good method for intraoperative flow assessment. However, the cost with the apparatus it entails limits its widespread use. We have developed a low-cost universal fluorescence module (FM) designed to visualize fluorescein and perform intraoperative angiography. The purpose of this paper is to describe this device as well as to present our early experience with its use in the treatment of cerebral aneurysms.

METHOD

A FM was designed and built using a cyan-blue narrow bandpass (460 to 490 nm) excitation filter and a yellow-orange longpass (blocking wavelengths under 520 nm) barrier filter mounted on a 3D-printed holding tray in a specific disposition to perfectly match the light source and the objective lens of the surgical microscope. It allowed switching from white light to fluorescence mode in a simple and sterile fashion. Its perfect attachment to the microscope was possible by reusing the lens fittings extracted from used original drape sets that would otherwise be discarded. Four patients underwent aneurysm clipping using the FM at two institutions from April to September 2018.

RESULTS

A bright green fluorescence against a dark background was observed after intravenous bolus of fluorescein. Blood vessels became obviously distinct from non-contrast-filled structures such as clipped aneurysms and the brain. Vascular anatomy could be appreciated without any distortion, including perforating arteries.

CONCLUSIONS

Intraoperative fluorescence angiography was successfully performed with the use of this universal FM after intravenous injection of fluorescein sodium. This simple and low-cost device may be useful in resource-limited centers, where other sorts of intraoperative angiography are not available.

Potential Risks and Limited Indications of the Supraorbital Keyhole Approach for Clipping Internal Carotid Artery Aneurysms

Background

Internal carotid artery (ICA) aneurysm may be a good target for supraorbital keyhole clipping. We discuss the surgical indications and risks of keyhole clipping for ICA aneurysms based on long-term clinical and radiologic results.

Methods

This was a retrospective analysis of 51 patients (aged 35–75 years, mean 62 years) with ICA aneurysms (mean 5.8 ± 1.8 mm) who underwent clipping via the supraorbital keyhole approach between 2005 and 2017. Neurologic and cognitive functions were examined by several methods, including the modified Rankin Scale and Mini-Mental Status Examination. The state of clipping was assessed 1 year and then every few years after the operation.

Results

Complete clipping was confirmed in 45 patients (88.2%), dog-ear remnants behind the clip persisted in 4 patients, and wrapping was performed in 2 patients. Mean duration of postoperative hospitalization was 3.4 ± 6.9 days. The mean clinical follow-up period was 6.6 ± 3.2 years. The overall mortality was 0, and overall morbidity (modified Rankin Scale score ≥2 or Mini-Mental Status Examination <24) was 3.9%. Completely clipped aneurysms did not show any recurrence during the mean follow-up period of 6.3 ± 3.1 years, but the 2 (3.9%) aneurysms with neck remnants showed regrowth.

Conclusions

The risk of neck remnant behind the clip blade is a drawback of supraorbital keyhole clipping. The surgical indication requires preoperative simulation and careful checking of the clip blade state is essential.

Evaluation of the yield of post-clipping angiography and nationwide current practice

BACKGROUND

Surgical treatment of intracranial saccular aneurysms aims to prevent (re)hemorrhage by complete occlusion of the aneurysmal lumen. It is unclear whether routine postoperative imaging, to assess aneurysmal occlusion, is necessary since intraoperative assessment by the neurosurgeon may be sufficient. We assessed routine clinical protocols for post-clipping imaging in the Netherlands and determined whether intraoperative assessment of aneurysm clippings sufficiently predicts aneurysm residuals.

METHODS

A survey was conducted to assess postoperative imaging protocols in centers performing clipping of intracranial aneurysms in the Netherlands (n = 9). Furthermore, a retrospective single-center cohort study was performed to determine the predictive value of intraoperative assessment of aneurysm occlusion in relation to postoperative digital subtraction angiography (DSA) findings, between 2009 and 2017.

RESULTS

No center performed intraoperative DSA in a hybrid OR, routinely. Respectively, four (44.4%), seven (77.8%), and three (33.3%) centers did not routinely perform early postoperative imaging, late follow-up imaging, or any routine imaging at all. Regarding our retrospective study, 106 patients with 132 clipped aneurysms were included. There were 23 residuals ≥ 1 mm (17.4%), of which 10 (43.5%) were unexpected. For the presence of these residuals, intraoperative assessment showed a sensitivity of 56.5%, a specificity of 86.2%, a positive predictive value of 46.4%, and a negative predictive value of 90.4%.

CONCLUSIONS

There is lack of consensus regarding the post-clipping imaging strategy in the Netherlands. Since intraoperative assessment is shown to be insufficient to predict postoperative aneurysm residuals, we advocate routine postoperative imaging after aneurysm clipping unless this is not warranted on the basis of patient age, clinical condition, and/or comorbidity.

Endoscope- versus microscope-integrated near-infrared indocyanine green videoangiography in aneurysm surgery

OBJECTIVE

The quality of surgical treatment of intracranial aneurysms is determined by complete aneurysm occlusion while preserving blood flow in the parent, branching, and perforating arteries. For a few years, there has been a nearly noninvasive and cost-effective technique for intraoperative flow evaluation: microscope-integrated indocyanine green videoangiography (mICG-VA). This method allows for real-time information about blood flow in the aneurysm and the involved vessels, but its limitations are seen in the evaluation of structures located in the depth of the surgical field, especially through small craniotomies. To compensate for these drawbacks, an endoscope-integrated ICG-VA (eICG-VA) was developed. The objective of the present study was to assess the use of eICG-VA in comparison with mICG-VA for intraoperative blood flow evaluation.

METHODS

In the period between January 2011 and January 2015, 216 patients with a total of 248 intracranial saccular aneurysms were surgically treated in the Department of Neurosurgery of Saarland University Medical Center in Homburg/Saar, Germany. During 95 surgeries in 88 patients with a total of 108 aneurysms, intraoperative evaluation was performed with both eICG-VA and mICG-VA. After clipping, evaluation of complete aneurysm occlusion and flow in the parent, branching, and perforating arteries was performed using both methods. Intraoperative applicability of each technique was compared with the other and with postoperative digital subtraction angiography as a standard evaluation technique.

RESULTS

Evaluation of completeness of aneurysm occlusion and of flow in the parent, branching, and perforating arteries was more successful with eICG-VA than with mICG-VA, especially for aneurysm neck assessment (88.9% vs 69.4%). For 63.9% of the aneurysms (n = 69), both methods were equivalent, but in 30.6% of the cases (n = 33), the eICG-VA provided better results for evaluating the post-clipping situation. In 4.6% of these aneurysms (n = 5), the information given by the additional endoscope considerably changed the surgical procedure. Thus, one residual aneurysm (0.9%), two neck remnants (1.9%), and two branch occlusions (1.9%) could be prevented. Nevertheless, two incomplete aneurysm occlusions (1.9%) and six neck remnants (5.6%) were revealed by postoperative digital subtraction angiography.

CONCLUSIONS

Endoscope-integrated ICG-VA seems to be an improvement that might increase the quality of aneurysm surgery by providing additional information. It offers higher illumination, magnification, and an extended viewing angle. Its main advantage is its ability to assess deep-seated aneurysms, especially through small craniotomies, but further studies are required.

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.

Therapeutic strategies for residual or recurrent intracranial aneurysms after microsurgical clipping

OBJECTIVES

Therapeutic strategies for residual or recurrent aneurysm (RRA) after microsurgical clipping have not been well established. The purpose of this study was to report our retreatment experiences with previously clipped aneurysms and to demonstrate retreatment strategies for these RRAs.

PATIENTS AND METHODS

From 1996-2016, we treated 68 RRAs after previous clipping. Among them, 34 patients underwent microsurgical retreatment, and the other 34 underwent endovascular retreatment. Radiographic images and clinical data were reviewed retrospectively to determine the treatment efficacy, clinical outcomes, and important factors for selecting the proper treatment modality.

RESULTS

The most common aneurysm location was the middle cerebral artery (50%) in the microsurgery group and the internal carotid artery (47.1%) in the endovascular surgery group (p =  0.001). In the microsurgery group, 16 (47.1%) patients had additional clipping without removal of previous clips, 17 (50.0%) had clipping with removal of previous clips, and 1 (2.9%) had bypass surgery with trapping. In the endovascular surgery group, 28 (82.4%) patients had simple coiling, 5 (14.7%) had stent-assisted coiling, and 1 (2.9%) had a flow diverter. Procedure-related complications during retreatment occurred in 4 (5.9%) patients. Complete obliteration was achieved in 51 (75.0%) patients (microsurgery group, 82.4% and endovascular surgery group, 67.6%; p =  0.002).

CONCLUSIONS

In properly selected cases, treatment of RRAs could be safely performed either by microsurgery or endovascular surgery and result in a good clinical outcome with acceptable morbidity. The decision to choose the treatment modality for RRAs after clipping is not easy but should be considered to lower the risk of retreatment.

Endovascular coiling versus neurosurgical clipping for people with aneurysmal subarachnoid haemorrhage

BACKGROUND

Around 30% of people who are admitted to hospital with aneurysmal subarachnoid haemorrhage (SAH) will rebleed in the initial month after the haemorrhage if the aneurysm is not treated. The two most commonly used methods to occlude the aneurysm for prevention of rebleeding are microsurgical clipping of the neck of the aneurysm and occlusion of the lumen of the aneurysm by means of endovascular coiling. This is an update of a systematic review that was previously published in 2005.

OBJECTIVES

To compare the effects of endovascular coiling versus neurosurgical clipping in people with aneurysmal SAH on poor outcome, rebleeding, neurological deficit, and treatment complications.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (March 2018). In addition, we searched CENTRAL (2018, Issue 2), MEDLINE (1966 to March 2018), Embase (1980 to March 2018), US National Institutes of Health Ongoing Trials Register (March 2018), and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (last searched March 2018). We also contacted trialists.

SELECTION CRITERIA

We included randomised trials comparing endovascular coiling with neurosurgical clipping in people with SAH from a ruptured aneurysm.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, and assessed trial quality and risk of bias using the GRADE approach. We contacted trialists to obtain missing information. We defined poor outcome as death or dependence in daily activities (modified Rankin scale 3 to 6 or Glasgow Outcome Scale (GOS) 1 to 3). In the special worst-case scenario analysis, we assumed all participants in the group with better outcome with missing follow-up information had a poor outcome and those in the other group with missing data a good outcome.

MAIN RESULTS

We included four randomised trials involving 2458 participants (range per trial: 20 to 2143 participants). Evidence is mostly based on the largest trial. Most participants were in good clinical condition and had an aneurysm on the anterior circulation. None of the included trials was at low risk of bias in all domains. One trial was at unclear risk in one domain, two trials at unclear risk in three domains, and one trial at high risk in one domain.After one year of follow-up, 24% of participants randomised to endovascular treatment and 32% of participants randomised to the surgical treatment group had poor functional outcome. The risk ratio (RR) of poor outcome (death or dependency) for endovascular coiling versus neurosurgical clipping was 0.77 (95% confidence interval (CI) 0.67 to 0.87; 4 trials, 2429 participants, moderate-quality evidence), and the absolute risk reduction was 7% (95% CI 4% to 11%). In the worst-case scenario analysis for poor outcome, the RR for endovascular coiling versus neurosurgical clipping was 0.80 (95% CI 0.71 to 0.91), and the absolute risk reduction was 6% (95% CI 2% to 10%). The RR of death at 12 months was 0.80 (95% CI 0.63 to 1.02; 4 trials, 2429 participants, moderate-quality evidence). In a subgroup analysis of participants with an anterior circulation aneurysm, the RR of poor outcome was 0.78 (95% CI 0.68 to 0.90; 2 trials, 2157 participants, moderate-quality evidence), and the absolute risk decrease was 7% (95% CI 3% to 10%). In subgroup analysis of those with a posterior circulation aneurysm, the RR was 0.41 (95% CI 0.19 to 0.92; 2 trials, 69 participants, low-quality evidence), and the absolute decrease in risk was 27% (95% CI 6% to 48%). At five years, 28% of participants randomised to endovascular treatment and 32% of participants randomised to surgical treatment had poor functional outcome. The RR of poor outcome for endovascular coiling versus neurosurgical clipping was 0.87 (95% CI 0.75 to 1.01, 1 trial, 1724 participants, low-quality evidence). At 10 years, 35% participants allocated to endovascular and 43% participants allocated to surgical treatment had poor functional outcome. At 10 years RR of poor outcome for endovascular coiling versus neurosurgical clipping was 0.81 (95% CI 0.70 to 0.92; 1 trial, 1316 participants, low-quality evidence). The RR of delayed cerebral ischaemia at two to three months for endovascular coiling versus neurosurgical clipping was 0.84 (95% CI 0.74 to 0.96; 4 trials, 2450 participants, moderate-quality evidence). The RR of rebleeding for endovascular coiling versus neurosurgical clipping was 1.83 (95% CI 1.04 to 3.23; 4 trials, 2458 participants, high-quality evidence) at one year, and 2.69 (95% CI 1.50 to 4.81; 1 trial, 1323 participants, low-quality evidence) at 10 years. The RR of complications from intervention for endovascular coiling versus neurosurgical clipping was 1.05 (95% CI 0.44 to 2.53; 2 trials, 129 participants, low-quality evidence).

AUTHORS' CONCLUSIONS

The evidence in this systematic review comes mainly from one large trial, and long-term follow-up is available only for a subgroup of participants within that trial. For people in good clinical condition with ruptured aneurysms of either the anterior or posterior circulation the data from randomised trials show that, if the aneurysm is considered suitable for both neurosurgical clipping and endovascular coiling, coiling is associated with a better outcome. There is no reliable trial evidence that can be used directly to guide treatment in people with a poor clinical condition.

A Meta-Analysis of Risk Factors for the Formation of de novo Intracranial Aneurysms

BACKGROUND

Understanding the risk factors for the formation of de novo intracranial aneurysms (IAs) is important for patients who have ever suffered a cerebral aneurysm.

OBJECTIVE

To estimate the risk factors for the development of a de novo IA to identify which patients need more aggressive surveillance after aneurysm treatment.

METHODS

We followed the preferred reporting items for systematic reviews and meta-analyses guidelines and searched the PubMed, CENTRAL, EMBASE, and LILACS databases using the key words cerebral aneurysms, de novo, IAs, risk factors combined using and/or. The search was performed in July 2017.We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using RevMan 5.3 (Cochrane, London, United Kingdom) to evaluate risk factors. Statistical significance was set at P < .05.

RESULTS

The analysis included 14 studies involving 6389 patients, of whom 197 patients had de novo IAs. The main risk factors for formation included sex (OR = 1.82, 95% CI [1.30,2.56], P = .0005, female vs male), age <40 yr (OR = 2.96, 95% CI [1.76,4.96], P < .0001), family history (OR = 2.05, 95% CI [1.07,3.93], P = .03), smoking history (OR = 2.73, 95% CI [1.81,4.12], P < .0001), and multiple saccular intracranial aneurysms (sIAs) at first diagnosis (OR = 2.10, 95% CI [1.12,3.91], P = .02), internal carotid artery (ICA) as the initial site (OR = 2.58, 95% CI [1.43,4.68], P = .002). Heterogeneous analysis showed that these I2 were less than 50% and the results were reliable.

CONCLUSION

Observational evidence identified multiple clinical and anatomic risk factors for the formation of de novo IAs, including female sex, age <40 yr, family history, smoking history, multiple sIAs at first diagnosis, and IC as the initial site. More aggressive long-term angiographic follow-up with digital subtraction angiography, computed tomography angiography, or magnetic resonance angiography is recommended for these patients.

Management of Small Incidental Intracranial Aneurysms

Advances in neuroimaging and its widespread use for screening have increased the diagnosis of unruptured intracranial aneurysms (UIAs), including small-sized UIAs. The clinical management of these small-sized UIAs requires a patient-specific judgment of the risk of aneurysm rupture, if not treated, versus the risk of complications from surgical or endovascular treatment. Experienced cerebrovascular teams recommend treating small UIAs in young patients or in patients with more than one aneurysm rupture risk factor who also have a reasonable life expectancy. However, individual overall assessment of risk is critical for patients with UIAs to decide the next steps of care.

Risk of de novo aneurysm formation in patients with unruptured intracranial aneurysms

BACKGROUND AND PURPOSE

The rate of de novo aneurysm formation in patients with unruptured aneurysm without history of subarachnoid hemorrhage is scarcely defined in literature. We report the incidence of de novo aneurysm formation in a large contemporary series of patients with unruptured intracranial aneurysm (UIA) undergoing serial neurovascular imaging.

METHODS

Neurovascular imaging studies of 321 consecutive UIA patients with no prior history of subarachnoid hemorrhage, with at least 3 years of follow-up imaging, were reviewed by a neuroradiologist and a neurosurgeon. Rate of de novo aneurysm formation was reported on a per-patient and per-patient-year basis.

RESULTS

Of the 321 included patients, three patients (0.9%) developed a de novo aneurysm over a mean follow-up period of 5.2 years, for an incidence rate of 0.18% per patient-year. No de novo aneurysms ruptured and all three were 2 mm in size.

CONCLUSIONS

The rate of de novo aneurysm formation in patients with unruptured aneurysms and no history of subarachnoid hemorrhage is very low. These data are useful to advice patients with unruptured aneurysms from another aneurysm and to plan imaging follow-ups in these patients.

Endoscopic Endonasal Clipping of Anterior Circulation Aneurysm: Surgical Techniques and Results

BACKGROUND

Endoscopic endonasal clipping of intracranial aneurysms may use microsurgical techniques as an alternative to the transcranial approach. Here we report a series of patients who underwent microsurgical clipping of anterior circulation aneurysms via an endoscopic endonasal approach (EEA).

METHODS

This retrospective chart review included all the patients who underwent standard binostril EEA for aneurysm clipping. Surgical outcomes and complications are noted. The rationality and limitations of this procedure are discussed.

RESULTS

Seven patients with 12 aneurysms of the anterior circulation underwent EEA for clipping. These 12 aneurysms consisted of 5 anterior communicating artery (AComA) aneurysms, 4 paraclinoid aneurysms, 1 ophthalmic artery aneurysm, and 2 aneurysm located in the cavernous segment of internal carotid artery (ICA). Nine of the 12 aneurysms were successfully clipped. One giant paraclinoid aneurysm could not be clipped during operation and was coiled in second endovascular stage. The 2 aneurysms located in the cavernous segment of ICA were not clipped intentionally in a single-stage procedure, after weighing the surgical benefit against the difficulty of surgical exposure and feasibility. The proximal control of ICA was achieved in all cases. There was no death, no cerebrospinal fluid leak, or other complications. All patients recovered completely.

CONCLUSIONS

EEA can provide direct access for microsurgical clipping of strictly selected anterior circulation aneurysms. All the principles of cerebrovascular surgery must be followed. These procedures require a long learning curve. Only teams with adequate experience in microvascular and endoscopic skull base surgeries should attempt this approach for treating aneurysms.

Evaluation of safety, efficacy and clinical outcome after endovascular treatment of aneurysmal subarachnoid hemorrhage in coil-first setting. A 10-year series from a single center

INTRODUCTION

The endovascular treatment (EVT) of ruptured cerebral aneurysms has been widely adopted after the publication of the International Subarachnoid Aneurysm Trial. In this study, we sought to evaluate the safety and efficacy of the EVT for ruptured aneurysms based on 10-year series from a single center with coil-first strategy.

METHODS

All patients with aneurysmal subarachnoid hemorrhage (aSAH) treated between 2007 and 2016 were retrospectively reviewed and divided according to initial treatment into an EVT and a microsurgical clipping (MSC) group. Clinical and radiological findings at presentation, treatment modalities and procedural complications were recorded. The angiographic and clinical outcome was compared between the two groups.

RESULTS

A total of 587 patients with aSAH were reviewed (452 EVT, 135 MSC). There were no significant differences in mean age or the Hunt and Hess grades. Parenchymal hemorrhage (PH) was more frequent in the MSC. Procedure related complications of the acute treatment were recorded in 5.5% and 32% in the EVT and MSC, respectively. The rate of retreatment was 21.9% in the EVT and 5.9% in the MSC. Late rehemorrhage was not observed in either group. There was no significant difference in the clinical outcome between the two treatment groups after adjustment for other prognostic factors.

CONCLUSION

The majority of ruptured intracranial aneurysms can be managed via an endovascular approach in the acute phase with excellent safety profile and good efficacy. Despite the high rate of reperfusion after primary endovascular approach, retreatment has a very low rate of complications and the rate of recurrent hemorrhage is very low.

Vascular assessment after clipping surgery using four-dimensional CT angiography

Recent advances in computed tomography angiography (CTA) enable repeated imaging follow up for post-clipping surgery. The purpose of this study was to clarify the critical volume and configuration of the aneurysmal clip in the postoperative evaluation using volume rendering (VR) imaging, and present four-dimensional (4D)-CTA for these larger metal artifacts. A total of 44 patients with cerebral aneurysm, treated using clipping surgery, were included in this study. The metal artifact volume was assessed using CTA and the association between the type of clips and its metal artifact volume was analyzed. A VR image and a 4D-CTA were then produced, and the diagnostic accuracy of arteries around the clip or residual aneurysm on these images was evaluated. In the receiver operating characteristic (ROC) curve analysis, the cutoff value for metal artifacts was 2.32 mm³ as determined through a VR image. Patients were divided into two groups. Group 1 included patients with a simple and small clip, and group 2 included patients with multiple, large or fenestrated clips. The metal artifact volume was significantly larger in group 2, and the group incorporated the cutoff value. Post-clipping status on the VR image was significantly superior in group 1 compared with group 2. In group 2, the imaging quality of post-clipping status on 4D-CTA was superior in 92.9% of patients. The metal artifact volume was dependent on the number, size, or configuration of the clip used. In group 2, evaluation using a 4D-CTA eliminated the effect of the metal artifacts.

Long-term follow-up in the endovascular treatment of intracranial aneurysms with flow-diverter stents: update of a single-centre experience

INTRODUCTION

Flow-diverter stents are becoming a useful tool in treating patients with intracranial aneurysms with suitable anatomical feature. Purpose of this study was to evaluate effectiveness and safety of endovascular treatment with flow-diverting stents (FD) in unruptured intracranial aneurysms.

METHODS

From May 2009 and May 2014, we treated 49 patients with a total of 58 aneurysms, with FD technique. All patients were treated electively, under general anesthesia and were administered single antiplatelet drug 5 days before the procedure and double antiplatelet therapy for 3 months afterwards. Fifteen of the patients were asymptomatic, eight had headache, thirteen patients presented symptoms due to mass effect of the aneurysm on CNS structures, twelve were treated due to a post-surgical relapse and one patient presented relapsing TIAs due to distal embolization from the aneurysm dome. Choice of FD treatment was done according to aneurysm anatomy (fusiform over saccular, dome/neck ratio < 2) and whenever conventional treatment (coil embolization) appeared difficult (eg. Large aneurysm neck, fusiform aneurysms or difficult sac catheterization). We considered a dome/neck ratio > 2 as the only exclusion criteria.

RESULTS

Successful stent deployment was achieved in 50 procedures out of 52 (94.34%) while overall mortality was 2% (1/49). Forty-eight patients were evaluated at long-term follow-up for a total of 56 treated aneurysms. At 3 months, follow-up 75% (42/56) of the aneurysms were excluded from intracranial circulation, at 6 months 80.35% (45/56) and at 12 months 84% (47/56). Stent patency was observed in 100% of patients at short and long-term follow-up, with only two cases of intimal hyperplasia at 3 months, without any further complications.

CONCLUSIONS

According to our study FD repair of unruptured intracranial aneurysms appeared to be a safe and effective technique, especially in selected patients with hostile anatomy for traditional embolization.

Subarachnoid hemorrhage after surgical treatment of unruptured intracranial aneurysms

OBJECTIVE Only a few previous studies have investigated subarachnoid hemorrhage (SAH) after surgical treatment in patients with unruptured intracranial aneurysms (UIAs). Given the improvement in long-term outcomes of embolization, more extensive data are needed concerning the true rupture rates after microsurgery in order to provide reliable information for treatment decisions. The purpose of this study was to investigate the incidence of and risk factors for postoperative SAH in patients with surgically treated UIAs. METHODS Data from 702 consecutive patients harboring 852 surgically treated UIAs were evaluated. Surgical treatments included neck clipping (complete or incomplete), coating/wrapping, trapping, proximal occlusion, and bypass surgery. Clippable UIAs were defined as UIAs treated by complete neck clipping. The annual incidence of postoperative SAH and risk factors for SAH were studied using Kaplan-Meier survival analysis and Cox proportional hazards regression models. RESULTS The patients' median age was 64 years (interquartile range [IQR] 56-71 years). Of 852 UIAs, 767 were clippable and 85 were not. The mean duration of follow-up was 731 days (SD 380 days). During 1708 aneurysm years, there were 4 episodes of SAH, giving an overall average annual incidence rate of 0.23% (95% CI 0.12%-0.59%) and an average annual incidence rate of 0.065% (95% CI 0.0017%-0.37%) for clippable UIAs (1 episode of SAH, 1552 aneurysm-years). Basilar artery location (adjusted hazard ratio [HR] 23, 95% CI 2.0-255, p = 0.0012) and unclippable UIA status (adjusted HR 15, 95% CI 1.1-215, p = 0.046) were significantly related to postoperative SAH. An excellent outcome (modified Rankin Scale score of 0 or 1) was achieved in 816 (95.7%) of 852 cases overall and in 748 (98%) of 767 clippable UIAs at 12 months. CONCLUSIONS In this large case series, microsurgical treatment of UIAs was found to be safe and effective. Aneurysm location and unclippable morphologies were related to postoperative SAH in patients with surgically treated UIAs.

Angiographic and epidemiological characteristics associated with aneurysm remnants after microsurgical clipping

BACKGROUND

Despite new techniques for the treatment of cerebral aneurysms, the percentage of aneurysm remnants after surgical intervention seems to be relatively constant. The objective of this study was to assess angiographic and epidemiological features associated with aneurysm remnants after microsurgical clipping.

METHODS

This study was conducted from February 2009 to August 2012 on a series of 90 patients with 105 aneurysms referred to the Santa Casa of Belo Horizonte who were surgically treated and angiographically controlled.

RESULTS

Surgical clipping was considered incomplete in 13.3% of the aneurysms. The mean age of cases with an aneurysm remnant was 57.5 years, whereas the mean age without aneurysm remnant was 49.7 years (P = 0.02). Aneurysm remnants were detected more frequently on the internal carotid artery, nevertheless, no statistically significant differences were verified when comparing the locations. Aneurysm size in the preoperative angiography verified that the mean size of aneurysms operated was 6.56 mm, such that in cases showing a postoperative remnant, the mean size was 9.7 mm and in cases with complete clipping it was 6.08 mm (P = 0.02). Postoperative angiography showed that, in cases with residual aneurysm, the number of clips used was higher - a mean of 1.8 for complete clipping and 3.1 for incomplete clipping (P < 0.001).

CONCLUSIONS

Aneurysm size and patient age showed significant correlations with residual intracranial aneurysm. The mean number of clips used was higher in cases with incomplete occlusion.

Indocyanine Green Videoangiography in Aneurysm Surgery: Systematic Review and Meta-Analysis

BACKGROUND

Although digital subtraction angiography (DSA) may be considered the gold standard for intraoperative vascular imaging, many neurosurgical centers rely only on indocyanine green videoangiography (ICG-VA) for the evaluation of clipping accuracy. Many studies have compared the results of ICG-VA with those of intraoperative DSA; however, a systematic review summarizing these results is still lacking.

OBJECTIVE

To analyze the literature in order to evaluate ICG-VA accuracy in the identification of aneurysm remnants and vessel stenosis after aneurysm clipping.

METHODS

We performed a systematic literature review of ICG-VA accuracy during aneurysm clipping as compared to microscopic visual observation (primary endpoint 1) and DSA (primary endpoint 2). Quality of studies was assessed with the QUADAS-2 tool. Meta-analysis was performed using a random effects model.

RESULTS

The initial PubMed search resulted in 2871 records from January 2003 to April 2016; of these, 20 articles were eligible for primary endpoint 1 and 11 for primary endpoint 2. The rate of mis-clippings that eluded microscopic visual observation and were identified at ICG-VA was 6.1% (95% CI: 4.2-8.2), and the rate of mis-clippings that eluded ICG-VA and were identified at DSA was 4.5% (95% CI: 1.8-8.3).

CONCLUSION

Because a proportion of mis-clippings cannot be identified with ICG-VA, this technique should still be considered complementary rather than a replacement to DSA during aneurysm surgery. Incorporating other intraoperative tools, such as flowmetry or electrophysiological monitoring, can obviate the need for intraoperative DSA for the identification of vessel stenosis. Nevertheless, DSA likely remains the best tool for the detection of aneurysm remnants.

Comparison of Efficacy of Intraoperative Indocyanine Green Videoangiography in Clipping of Anterior Circulation Aneurysms with Postoperative Digital Subtraction Angiography

Introduction:

The aim of this study is to assess the efficacy of intraoperative indocyanine green videoangiography (ICG-VA) using postoperative digital subtraction angiography (DSA) in clipped anterior circulation aneurysms.

Materials and Methods:

A prospective study was conducted for 1 year which included thirty patients of anterior circulation aneurysm treated by clipping of aneurysm. Intraoperative ICG-VA was performed on all the patients. Postoperative DSA was performed to assess the efficacy of ICG-VA.

Results:

Intraoperative ICG-VA revealed the occlusion of aneurysm in all the thirty patients. Postoperative DSA revealed aneurysm neck remnant in two patients and demonstrated no branch occlusion.

Conclusions:

Intraoperative ICG-VA is useful in assessing the completeness of clipping of cerebral aneurysms and ensures patency of branch vessels, thus providing a better postoperative outcome. It replaces the need for invasive postoperative angiographic imaging in a selected group of patients and is also cost effective.

Risk factors for angiographic recurrence after treatment of unruptured intracranial aneurysms: Outcomes from a series of 178 unruptured aneurysms treated by regular coiling or surgery

BACKGROUND

Long-term stability after intracranial aneurysm exclusion by coiling is still a matter of debate; after surgical clipping little is known.

OBJECTIVE

To study outcome after endovascular and surgical treatments for unruptured intracranial aneurysms in terms of short- and long-term angiographic exclusion and risk factors for recanalization.

METHODS

From 2004 and 2009, patients treated for unruptured berry intracranial aneurysms by coiling or clipping were reviewed. Aneurysmal exclusion was evaluated using the Roy-Raymond grading scale; immediate clinical outcome was also assessed. Clinical outcome, recanalization, risk factors for recurrence and bleeding during the follow-up period were analyzed by groups; "surgery" and "embolization".

RESULTS

From 2004 to 2009, 178 consecutive unruptured aneurysms were treated. The post-procedure angiographic results for "surgery" were: total exclusion 75.6%; residual neck 13.5%; residual aneurysm 10.8%. For "embolization", the results were, respectively: 72%; 20.7%; and 7.2%. Morbidity was 3% for "surgery" and 1.6% for "embolization" (P=0.74); mortality was nil. Mean clinical and angiographic follow-up was 5years. Recurrence rate was of 11.5% for "surgery" vs. 44% for "embolization" with a mean follow-up of 4 and 5.75years, respectively (P=1.10-5). The retreatment rate was 8.4%. Two significant risk factors for recanalization were identified: maximum diameter of the aneurysm sac (P=0.0038) and pericallosal location (P=0.0388). No bleeding event occurred.

CONCLUSION

Both techniques are safe. The rate of aneurismal recurrence was significantly higher for embolization, especially for large diameter aneurysms and pericallosal locations. No bleeding event occurred after recanalization.

Dual- versus Single-Energy CT-Angiography Imaging for Patients Undergoing Intracranial Aneurysm Repair

BACKGROUND

The invasiveness and risk of thromboembolic complications of catheter angiography underline the need for alternative imaging modalities in patients following intracranial aneurysm (IA) repair. However, the overall image quality of existing noninvasive imaging modalities, such as single-energy CT angiography (SE-CTA), compromises its value in this respect.

OBJECTIVE

We prospectively investigated the value of a novel dual-energy CTA (DE-CTA) scanner and algorithm for assessing the degree of occlusion and parent vessel patency in patients following IA repair.

METHODS

A prospective cohort of 17 patients underwent DE-CTA imaging following surgical or endovascular IA repair. This dataset was matched with an identical historical cohort of 17 patients, who underwent IA repair and SE-CTA imaging. Beam-hardening artifacts, as a measure for objective imaging quality were analyzed based on the volume of a prolate ellipsoid, whereas subjective imaging quality at the IA site and corresponding parent vessels was rated by 2 independent neuroradiologists on a scale from 4 (excellent, no artifacts) to 1 (poor, severe artifacts).

RESULTS

Objective DE-CTA image quality was markedly higher, compared to SE-CTA in patients undergoing surgical (0.77 ± 0.23 vs. 10.91 ± 1.88 mL, respectively; p < 0.001) or endovascular (32.36 ± 10.62 vs. 107.63 ± 24.51 mL, respectively; p = 0.026) IA repair. Subjective image quality for DE-CTA was significantly improved compared to SE-CTA in the surgical group but not in the endovascular group. The calculated dose values for DE-CTA in our study remain markedly below the legally required radiation dose limits.

CONCLUSION

The imaging quality of DE-CTA, especially for patients undergoing surgical IA repair, is distinctly superior, compared to SE-CTA imaging. Therefore, DE-CTA may serve as a noninvasive alternative for assessing the IA occlusion rate and parent vessel patency.

A long-term study of durability and risk factors for aneurysm recurrence after microsurgical clip ligation

OBJECTIVE

With the recent evolution of endovascular therapies, objective evaluation of the efficacy of clip ligation for cerebral aneurysms should be performed. This study was undertaken to evaluate the durability of microsurgical clip ligation, identify risk factors for recurrence, and assess the need for long-term follow-up imaging.

METHODS

A retrospective review of medical records identified 616 consecutive patients (156 male and 460 female patients; mean age 48.4 ± 12.4 years; range 6–90 years) who underwent microsurgical clip ligation and follow-up imaging at least 1 year after discharge between 1990 and 2010 at our institution. Of a total of 926 aneurysms in 616 patients, 758 aneurysms were microsurgically clip-ligated. At presentation, 431 of these aneurysms were ruptured and 327 aneurysms were unruptured. All patients underwent postoperative baseline imaging within the 1st month of their operation. A logistic regression analysis was performed to identify which variables are more likely to predict recurrence.

RESULTS

Late follow-up angiographic imaging was obtained at a mean of 7.2 ± 4.7 years postdischarge (median 5.7 years; range 1–23 years). Of the 699 clipped aneurysms without residua, late follow-up angiography revealed only 1 (0.14%) recurrent aneurysm. Of the 59 residual aneurysms that remained after initial clip ligation on early postoperative imaging, 8 (13.6%) demonstrated growth. All of these aneurysms required treatment. None of the recurrences were due to broken or delayed displacement of clips. A total of 111 patients presented with multiple aneurysms. De novo aneurysm formation occurred in 8 (0.97%) patients, all of whom initially presented with multiple aneurysms.

CONCLUSIONS

This study provides additional evidence to support the long-term efficacy of aneurysm clip ligation. The chance of aneurysm recurrence after complete clip ligation is very small. However, there is a regrowth risk of 1.83% per year for aneurysm remnants after incomplete clip ligation. These findings support the necessity for continued followup, late angiographic imaging, and the potential need for further intervention of incompletely ligated aneurysms. Furthermore, completely clip-ligated aneurysms may not require additional surveillance imaging unless multiple aneurysms were evident at presentation.

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.

Microsurgical Clipping of Unruptured Intracranial Aneurysms: A Single Surgeon's Experience over 16 Years

BACKGROUND

Unruptured intracranial aneurysms (UIAs) have become an issue of greater significance as their detection rates have increased over the years. We present the overall experience of microsurgical clipping of unruptured aneurysms by a single surgeon over a period of more than 16 years.

METHODS

The clinical and radiologic data were reviewed retrospectively. Clinical outcome at follow-up was assessed with Glasgow Outcome Scale, and angiograms were reviewed for the degree of occlusion.

RESULTS

One hundred ninety-six patients with 221 UIAs were included in the analysis. The median age of patients was 54 years, with a female preponderance. Eighty-two percent of the patients had chronic headache on presentation. Middle cerebral artery aneurysms (32.2%) and posterior-inferior-cerebellar-artery aneurysms (46.1%) were most common in the anterior and posterior circulation, respectively. The perioperative complication rate was 17.3%. The overall surgical morbidity and mortality were 2.1% and 1.5%, respectively. With median follow-up of 11.3 months, 82% of patients were almost asymptomatic with a complete occlusion rate of 94%. The proportion of UIAs being coiled has significantly increased in the last decade, with a concomitant increase in the risk of poor clinical outcome after surgery.

CONCLUSION

Surgical clipping is effective and can provide a good long-term outcome. The most commendable consequence that it provides is a better long-term occlusion rate. The experience of the individual surgeon is important for a superior and enduring overall outcome. An increase in the rate of coiling in recent years has affected the outcome rate after surgery that calls for further evaluation.

Aneurysm remnant after clipping: the risks and consequences

OBJECTIVE

The complete clipping of a cerebral aneurysm usually warrants its sustained occlusion, while clip remnants may have far-reaching consequences. The aim of this study is to identify the risk factors for clip remnants requiring retreatment and/or exhibiting growth.

METHODS

All consecutive patients with primary aneurysm clipping performed at University Hospital of Essen between January 1, 2003, and December 31, 2013, were eligible for this study. Aneurysm occlusion was judged on obligatory postoperative digital subtraction angiography and the need for repeated vascular control. The identified clip remnants were correlated with various demographic and clinical characteristics of the patients, aneurysm features, and surgery-related aspects.

RESULTS

Of 616 primarily clipped aneurysms, postoperative angiography revealed 112 aneurysms (18%) with clip remnants requiring further control (n = 91) or direct retreatment (n = 21). Seven remnants exhibited growth during follow-up, whereas 2 cases were associated with aneurysmal bleeding. Therefore, a total of 28 aneurysms (4.5%) were retreated as clip remnants (range 1 day to 67 months after clipping). In the multivariate analysis, the need for retreatment of clip remnant was correlated with the aneurysm's initial size (> 12 mm; OR 3.22; p = 0.035) and location (anterior cerebral artery > internal carotid artery > posterior circulation > middle cerebral artery; OR 1.85; p = 0.003). Younger age with a cutoff at 45 years (OR 33.31; p = 0.004) was the only independent predictor for remnant growth.

CONCLUSIONS

The size and location of the aneurysm are the main risk factors for clip remnants requiring retreatment. Because of the risk for growth, younger individuals (< 45 years old) with clip remnants require a long-term (> 5 years) vascular follow-up.

Clinical trial registration no: DRKS00008749 (Deutsches Register Klinischer Studien)

Open Surgery for Recurrent Intracranial Aneurysms: Techniques and Long-Term Outcomes

BACKGROUND

After occlusion of an aneurysm, a patient may experience aneurysm regrowth at the same site or develop de novo aneurysms. We present our experience in microsurgery of recurrent aneurysms with analysis of long-term results.

METHODS

The senior authors (R. T. and H. K.) performed recurrent aneurysm clipping on 44 patients at Teishinkai Hospital and Asahikawa Red Cross Hospital in Sapporo, Japan. Operative techniques included clipping only, clipping and protective bypass, trapping of aneurysm with bypass, proximal occlusion, and bypass. Postoperative outcome was analyzed retrospectively using the modified Rankin Scale.

RESULTS

Our series included 10 men (23%) and 34 women (77%), with a mean patient age of 63 years (range, 7-82 years). Before primary treatment, 11 patients (25%) had a ruptured aneurysm, while 33 patients (75%) had an unruptured aneurysm. The mean follow-up time after primary surgery was 7.6 years (range, 0.8-25 years). At our department the treatment of recurrent aneurysm included the clipping in 19 patients (43%), clipping with bypass in 6 patients (14%), aneurysm trapping with bypass in 10 patients (23%), and proximal occlusion and bypass in 9 patients (20%). The mean follow-up time after surgical treatment of recurrent aneurysms stood at 3.5 years (range 0.1-9 years). Altogether, 37 patients (84%) experienced favorable outcomes at last follow-up examination (modified Rankin Scale scores 0 and 1).

CONCLUSIONS

Microsurgery of recurrent aneurysms may be performed safely and effectively, as shown by our study, in which 84% of patients experienced favorable results.

Aneurysm growth and de novo aneurysms during aneurysm surveillance

OBJECTIVE Many low-risk unruptured intracranial aneurysms (UIAs) are followed for growth with surveillance imaging. Growth of UIAs likely increases the risk of rupture. The incidence and risk factors of UIA growth or de novo aneurysm formation require further research. The authors retrospectively identify risk factors and annual risk for UIA growth or de novo aneurysm formation in an aneurysm surveillance protocol. METHODS Over an 11.5-year period, the authors recommended surveillance imaging to 192 patients with 234 UIAs. The incidence of UIA growth and de novo aneurysm formation was assessed. With logistic regression, risk factors for UIA growth or de novo aneurysm formation and patient compliance with the surveillance protocol was assessed. RESULTS During 621 patient-years of follow-up, the incidence of aneurysm growth or de novo aneurysm formation was 5.0%/patient-year. At the 6-month examination, 5.2% of patients had aneurysm growth and 4.3% of aneurysms had grown. Four de novo aneurysms formed (0.64%/patient-year). Over 793 aneurysm-years of follow-up, the annual risk of aneurysm growth was 3.7%. Only initial aneurysm size predicted aneurysm growth (UIA < 5 mm = 1.6% vs UIA ≥ 5 mm = 8.7%, p = 0.002). Patients with growing UIAs were more likely to also have de novo aneurysms (p = 0.01). Patient compliance with this protocol was 65%, with younger age predictive of better compliance (p = 0.01). CONCLUSIONS Observation of low-risk UIAs with surveillance imaging can be implemented safely with good adherence. Aneurysm size is the only predictor of future growth. More frequent (semiannual) surveillance imaging for newly diagnosed UIAs and UIAs ≥ 5 mm is warranted.

Techniques and Outcomes of Gore-Tex Clip-Wrapping of Ruptured and Unruptured Cerebral Aneurysms

OBJECTIVE

Some aneurysms without a definable neck and associated parent vessel pathology are particularly difficult to treat and may require clipping with circumferential wrapping. We report the largest available contemporary series examining the techniques of Gore-Tex clip-wrapping of ruptured and unruptured intracranial aneurysms and patient outcomes.

METHODS

The presentation, location, and shape of the aneurysm; wrapping technique; outcome at discharge and last follow-up; and any change in the aneurysm at last angiographic follow-up were reviewed retrospectively in 30 patients with Gore-Tex clip-wrapped aneurysms.

RESULTS

Gore-Tex clip-wrapping was used in 8 patients with ruptured aneurysms and 22 patients with unruptured aneurysms. Aneurysms included 23 fusiform, 3 blister, and 4 otherwise complex, multilobed, or giant aneurysms. Of the 30 aneurysms, 63% were in the anterior circulation. The overall mean patient age was 52.5 years (range, 17-80 years). Postoperatively, there were no deaths or worsening of neurologic status and no parent vessel stenoses or strokes. The mean Glasgow Outcome Scale score at last follow-up was 4.7. The mean follow-up time was 42.3 months (median, 37.0 months; range, 3-96 months). There were 105.8 patient follow-up years. Aneurysms recurred in 2 patients with Gore-Tex clip-wrapping. No patients developed rehemorrhage. Overall risk of recurrence was 1.9% annually.

CONCLUSIONS

Gore-Tex has excellent material properties for circumferential wrapping of aneurysms and parent arteries. It is inert and does not cause a tissue reaction or granuloma formation. Gore-Tex clip-wrapping can be used safely for microsurgical management of ruptured and unruptured cerebral aneurysms with acceptable recurrence and rehemorrhage rates.

Techniques and long-term outcomes of cotton-clipping and cotton-augmentation strategies for management of cerebral aneurysms

OBJECTIVE To address the challenges of microsurgically treating broad-based, frail, and otherwise complex aneurysms that are not amenable to direct clipping, alternative techniques have been developed. One such technique is to use cotton to augment clipping ("cotton-clipping" technique), which is also used to manage intraoperative aneurysm neck rupture, and another is to reinforce unclippable segments or remnants of aneurysm necks with cotton ("cotton-augmentation" technique). This study reviews the natural history of patients with aneurysms treated with cotton-clipping and cotton-augmentation techniques. METHODS The authors queried a database consisting of all patients with aneurysms treated at Barrow Neurological Institute in Phoenix, Arizona, between January 1, 2004, and December 31, 2014, to identify cases in which cotton-clipping or cotton-augmentation strategies had been used. Management was categorized as the cotton-clipping technique if cotton was used within the blades of the aneurysm clip and as the cotton-clipping technique if cotton was used to reinforce aneurysms or portions of the aneurysm that were unclippable due to the presence of perforators, atherosclerosis, or residual aneurysms. Data were reviewed to assess patient outcomes and annual rates of aneurysm recurrence or hemorrhage after the initial procedures were performed. RESULTS The authors identified 60 aneurysms treated with these techniques in 57 patients (18 patients with ruptured aneurysms and 39 patients with unruptured aneurysms) whose mean age was 53.1 years (median 55 years; range 24-72 years). Twenty-three aneurysms (11 cases of subarachnoid hemorrhage) were treated using cotton-clipping and 37 with cotton-augmentation techniques (7 cases of subarachnoid hemorrhage). In total, 18 patients presented with subarachnoid hemorrhage. The mean Glasgow Outcome Scale (GOS) score at the time of discharge was 4.4. At a mean follow-up of 60.9 ± 35.6 months (median 70 months; range 10-126 months), the mean GOS score at last follow-up was 4.8. The total number of patient follow-up years was 289.4. During the follow-up period, none of the cotton-clipped aneurysms increased in size, changed in configuration, or rebled. None of the patients experienced early rebleeding. The annual hemorrhage rate for aneurysms treated with cotton-augmentation was 0.52% and the recurrence rate was 1.03% per year. For all patients in the study, the overall risk of hemorrhage was 0.35% per year and the annual recurrence rate was 0.69%. CONCLUSIONS Cotton-clipping is an effective and durable treatment strategy for intraoperative aneurysm rupture and for management of broad-based aneurysms. Cotton-augmentation can be safely used to manage unclippable or partially clipped intracranial aneurysms and affords protection from early aneurysm re-rupture and a relatively low rate of late rehemorrhage.

Timing of retreatment for patients with previously coiled or clipped intracranial aneurysms: Analysis of 156 patients with multiple treatments

Background:

Some patients require a second surgical intervention for recurrence of treated aneurysms, untreated aneurysms in patients with multiple lesions, or de novo aneurysm. This retrospective review of the data was undertaken to evaluate when retreatment is necessary after initial aneurysm treatment.

Methods:

Cerebral aneurysms in 1755 patients were treated via clipping or coiling between January 1995 and September 2012. Postoperative follow-up was performed at 6 months after treatment and was repeated every 12 months (or longer) after treatment using three-dimensional computed tomography angiography or magnetic resonance angiography.

Results:

A cumulative total of 156 patients (8.9%) (117 women, 39 men; mean age: 55.0 years; range: 25–79 years) needed retreatment for rupture or regrowth of aneurysm (n = 31; ruptured (R)/remaining unruptured (U), 26/5), formation of de novo aneurysm (n = 45; R/U, 23/22), known untreated aneurysm in patients with multiple lesions (n = 78; R/U, 5/73), and hemorrhage from undetected aneurysm (n = 2). The regrowth risk is higher after endovascular treatment than after craniotomy and clipping. Median time to retreatment was 187 months (range: 11–280 months) for regrowth, 165 months (range: 22–330 months) for de novo, and 24 months (range: 2.8–417 months) for known untreated aneurysm. Regrowth or known with subarachnoid hemorrhage were frequently treated within 2 years from initial treatment.

Conclusions:

Aneurysms with residua or untreated aneurysms in patients with multiple lesions carry a risk of bleeding during a relatively short period, whereas there is a small but significant risk of de novo formation and subsequent hemorrhage at over 10 years after previous treatment.

Endovascular treatment of intracranial aneurysms

Intracranial aneurysms are abnormal dilations of the intracranial vessels, in which all the layers of the vascular wall are affected by degenerative changes that lead to distension of the vessel. Intracranial aneurysms can be classified based on their anatomic location, size, and morphology. Subarachnoid hemorrhage is the most devastating clinical presentation. The goal of preventing hemorrhage or rehemorrhage can only be achieved by excluding the aneurysm from the cerebral circulation. Endovascular or surgical clipping can achieve this goal. Multiple surgical and endovascular approaches have been described for treatment of intracranial aneurysm. Surgical approaches for anterior-circulation intracranial aneurysms include: pterional, orbitozygomatic, and lateral supraorbital craniotomies. Modern microsurgical techniques involve skull base dissection to achieve adequate exposure with minimal brain retraction. Endovascular techniques can be divided into: parent artery reconstruction with coil deposition (primary coil, balloon-assisted coiling, stent-assisted coiling, and other new techniques such as neck reconstruction devices and intraluminal occlusion devices); reconstruction with flow diversion; and deconstructive techniques with involving parent artery sacrifice with or without bypass.

De novo giant A2 aneurysm following anterior communicating artery occlusion

BACKGROUND

De novo intracranial aneurysms are reported to occur with varying incidence after intracranial aneurysm treatment. They are purported to be observed, however, with increased incidence after Hunterian ligation; particularly in cases of carotid artery occlusion for giant or complex aneurysms deemed unclippable.

CASE DESCRIPTION

We report a case of right-sided de novo giant A2 aneurysm 6 years after an anterior communicating artery (ACoA) aneurysm clipping. We believe this de novo aneurysm developed in part due to patient-specific risk factors but also a significant change in cerebral hemodynamics. The ACoA became occluded after surgery that likely altered the cerebral hemodynamics and contributed to the de novo aneurysm. We believe this to be the first reported case of a giant de novo aneurysm in this location. Following parent vessel occlusion (mostly of the carotid artery), there are no reports of any de novo aneurysms in the pericallosal arteries let alone a giant one. The patient had a dominant right A1 and the sudden increase in A2 blood flow likely resulted in increased wall shear stress, particularly in the medial wall of the A2 where the aneurysm occurred 2 mm distal to the A1-2 junction.

CONCLUSION

ACoA preservation is a key element of aneurysm surgery in this location. Suspected occlusion of this vessel may warrant closer radiographic follow-up in patients with other risk factors for aneurysm development.

Validation of the Modified Raymond-Roy classification for intracranial aneurysms treated with coil embolization

BACKGROUND

The Raymond-Roy Occlusion Classification (RROC) qualitatively assesses intracranial aneurysm occlusion following endovascular coil embolization. The Modified Raymond-Roy Classification (MRRC) was developed as a refinement of this classification scheme, and dichotomizes RROC III occlusions into IIIa (opacification within the interstices of the coil mass) and IIIb (opacification between the coil mass and aneurysm wall) closures.

METHODS

To demonstrate in an external cohort the predictive accuracy of the MRRC, the records of 326 patients with 345 intracranial aneurysms treated with endovascular coil embolization from January 2007 to December 2013 were retrospectively analyzed.

RESULTS

Within this cohort, 84 (24.3%) and 83 aneurysms (24.1%) had MRRC IIIa and IIIb closures, respectively, during initial coil embolization. Progression to complete occlusion was more likely with IIIa than IIIb closures (53.6% vs 19.2%, p≤0.01), while recanalization was more likely with IIIb than IIIa closures (65.1% vs 27.4%, p<0.01). Kaplan-Meier estimates demonstrated a significant difference in the test of equality for progression to complete occlusion (p=0.02) and recurrence (p<0.01) between class IIIa and IIIb distributions. For the entire cohort, male gender (p<0.01), ruptured aneurysm (p=0.04), intraluminal thrombus (p<0.01), and MRRC IIIb closure (p<0.01) were identified as predictors of recanalization. For aneurysms with an initial RROC III occlusion, MRRC IIIa closure was found to be an independent predictor of progression to complete occlusion (p=0.02).

CONCLUSIONS

This study confirms that the MRRC enhances the predictive accuracy of the RROC.

Adenosine-induced transient asystole

Cerebral aneurysms are an important health issue in the United States, and the mortality rate following aneurysm rupture, or SAH, remains high. The treatment of these aneurysms uses endovascular options which include coil placement, stent assistant coiling and, recently, flow diversion. However, microsurgical clipping remains an option in those aneurysms not suited for endovascular therapy. These are often the more complicated aneurysms such as in large, giant aneurysms or deep-seated aneurysms. Circumferential visualization of the aneurysm, parent vessels, branches, perforators, and other neurovascular structures is important to prevent residual aneurysms or strokes from vessel or perforator occlusion. Decompression of the aneurysm sac is often required and we believe that adenosine-induced transient asystole should be an important option for clipping of complex cerebral aneurysms.

Computerized Angiographic Occlusion Rating for Ruptured Clipped Aneurysms is Superior to Subjective Occlusion Rating

BACKGROUND AND PURPOSE

The computerized occlusion rating to estimate angiographic occlusion of embolized aneurysms is superior to the subjective occlusion rating. In this study, we compared the 2 methods in the analysis of aneurysms clipped after subarachnoid hemorrhage.

MATERIALS AND METHODS

The pre- and postoperative angiographic images (DSA) of 95 selected patients were analyzed and stratified in 4 grades (grade 0 for 100%, grade I for <99%-90%, grade II for <89%-70%, grade III for <70% occlusion) by using the subjective (angiographic) occlusion rating and the computerized (angiographic) occlusion rating. For the subjective occlusion rating, the occlusion rate was estimated; for the computerized occlusion rating, the "occluded" and "nonoccluded" aneurysm areas were automatically calculated in square millimeters after outlining the ideal occlusion line.

RESULTS

With the subjective occlusion rating, 75 (78.9%), 12 (12.6%), 7 (7.4%), and 1 (1.1%) and with the computerized occlusion rating 45 (47.4%), 24 (25.3%), 20 (21.0%), and 6 (6.3%) patients had aneurysms stratified to grades 0, I, II and III, respectively. The interobserver variation was significant with the subjective occlusion rating but not with the computerized occlusion rating. The subjective occlusion rating overestimated aneurysm occlusion in 30 (31.6%) patients. Mean values were the following: subjective occlusion rating of 97.5 ± 6.3% and computerized occlusion rating of 93.5 ± 9.7%; P = < .001. No patient rebled, and 4 patients underwent retreatment during 36 ± 38.9 months; the predictive value (log-rank, Kaplan-Meier) of the subjective and computerized occlusion ratings with respect to retreatment was highly significant for both methods (subjective occlusion rating: χ(2), 29.65; P < .001; computerized occlusion rating: χ(2), 35.57, P < .001).

CONCLUSIONS

The 2 methods showed remarkable differences in the estimation of the angiographic occlusion rates of clipped aneurysms. The clearly lower interobserver variation of the computerized versus subjective occlusion rating may indicate a superiority of the computerized occlusion rating.

Neuronavigated microvascular Doppler sonography for intraoperative monitoring of blood flow velocity changes during aneurysm surgery - a feasible monitoring technique

INTRODUCTION AND AIM OF THE STUDY

The intraoperative microvascular Doppler sonography (iMDS) is a well-established tool in vascular surgery for blood flow velocity (BFV) monitoring, capable of detecting vessel occlusion. However, identification of subtotal vessel compromise is more difficult, since the measured BFV may substantially vary with changing insonation angles and insonated vessel segments. To keep these parameters constant we combined neuronavigation with iMDS (niMDS). The question was if niMDS allows the detection of subtotal vessel compromise in aneurysm surgery.

METHODS

During surgery, the 3-dimensional reconstruction of the CT-angiography, which was obtained routinely prior to surgery, was displayed by the neuronavigational system. Prior to clipping, neuronavigation was used to define target point and trajectory, which, by coupling the neuronavigational pointer with the Doppler probe, correspond to the insonated vessel segment and the insonation angle. After clipping, for each vessel segment, the same trajectory was used for all consecutive measurements. The mean BFVs pre- and post-clipping were documented.

RESULTS

We performed 82 BFV-measurements in 39 aneurysm surgeries. Mean deviation between pre- and post-clipping BFV values was 2.12cm/s. There was a significant correlation between the mean BFV values before and after clipping (r=0.45 [95% CI 17-66%]; p=0.002). One patient experienced new neurological deficits due to occlusion of a perforating vessel that was not insonated.

CONCLUSION

The study could not answer the question if niMDS can detect BFV changes after clipping indicating vessel compromise, as no subtotal vessel occlusion occurred in the 39 operations. However, we proofed that niMDS-measured BFVs only varied minimally in uncompromised vessels pre- and post-clipping, suggesting that vessel compromises might be easily detected during aneurysm surgery.

[De novo cerebral aneurysms]

OBJECTIVE

To substantiate the reasonability and duration of angiographic follow-up of patients operated on for cerebral aneurysms to rule out de novo aneurysm formation.

MATERIAL AND METHODS

The results of angiographic examination (cerebral angiography and SCT angiography) of 43 patients with cerebral aneurysms operated on at the Burdenko Neurosurgical Institute in 1995-2012 are analyzed. The follow-up duration varied from 1 to 14 years after surgery (mean duration, 5 years). Patients' age ranged from 14 to 56 years.

RESULTS

Control angiographic examination showed that de novo aneurysms were formed in 7 (16.2%) patients. A total of 8 de novo aneurysms were detected (in one case there were two aneurysms formed). All aneurysms, both the previously operated and the de novo ones, were located in the anterior part of the circle of Willis. De novo aneurysms were clipped in 5 cases; the cavity of the de novo aneurysm was occluded with spirals in one case. One patient with a small aneurysm of the middle cerebral artery refused surgery. Neither lethal nor unfavorable outcomes were recorded.

CONCLUSIONS

The patient groups with the high risk of de novo aneurysm formation are as follows: 1) young smokers with hypertension; 2) patients who developed clinical signs of the disease when being young; 3) patients subjected to proximal exclusion of the main artery; and 4) patients with multiple and familial forms of the pathology. Dynamic angiographic follow-up (SCT angiography or magnetic resonance angiography) for 1-3 years is recommended for these patients.