Three-dimensional Images Fusion Method Useful for Preoperative Simulation of Clipping Surgery for Cerebral Aneurysms

This study aimed to introduce a three-dimensional (3D) images fusion method for preoperative simulation of aneurysm clipping. Consecutive unruptured aneurysm cases treated with surgical clipping from March 2021 to October 2023 were included. In all cases, preoperative images of plain computed tomography (CT), CT angiography, magnetic resonance imaging (MRI) 3D fluid-attenuated inversion recovery, 3D heavily T2-weighted images, and 3D rotational angiography were acquired and transported into a commercial software (Ziostation2 Plus, Ziosoft, Inc. Tokyo, Japan). The software provided 3D images of skull, arteries including aneurysms, veins, and brain tissue that were freely rotated, magnified, trimmed, and superimposed. Using the 3D images fusion method, two operators predicted clips to be used in the following surgery. The predicted clips and actually used ones were compared to give agreement scores for the following factors: (1) type of clips (simple or fenestrated), (2) shape of clips (straight, curved, angled, or bayonet), and (3) clipping strategy (single or multiple). The agreement score ranged from 0 to 3 because a score of 1 or 0 was given for agreement or disagreement on each factor. Interoperator reproducibility was also evaluated. During the study period, 44 aneurysms from 37 patients were clipped. All procedures were successfully completed, thanks to the precisely reproduced surgical corridors with the 3D images fusion method. Agreement in clip prediction was good with mean agreement score of 2.4. Interobserver reproducibility was also high with the kappa value of 0.79. The 3D images fusion method was useful for preoperative simulation of aneurysm clipping.

[Russian study on brain aneurysm surgery: a continuation (RIHA II)]

OBJECTIVE

To assess the main performance indicators of neurosurgical departments in surgical treatment of cerebral aneurysms in the Russian Federation.

MATERIAL AND METHODS

We analyzed 22 neurosurgical departments (19 regional and 3 federal hospitals) in 2017 and 2021. The study enrolled 6.135 patients including 3.160 ones in 2017 and 2.975 ones in 2021. We studied the features of surgical treatment of cerebral aneurysms in different volume hospitals and factors influencing postoperative outcomes.

RESULTS

The number of surgeries for cerebral aneurysms decreased from 2.950 in 2017 to 2.711 in 2021. Postoperative mortality rate was 6.3% and 5.6%, respectively. The number of microsurgical interventions decreased from 60% in 2017 to 48% in 2021. The share of endovascular interventions increased from 40% to 52%, respectively. Endovascular embolization was accompanied by stenting in 55% of cases. Simultaneous revascularization was carried out in 2% of cases. In 2021, the number of patients undergoing surgery in acute period of hemorrhage increased to 70% (in 2017 - 61%). The number of hospitals performing more than 50 surgical interventions for cerebral aneurysms annually increased from 14 in 2017 to 17 in 2021.

CONCLUSION

Certain changes in neurosurgical service occurred in 2021 compared to 2017. Lower number of surgical interventions for cerebral aneurysms, most likely caused by the COVID-19 pandemic, is accompanied by lower postoperative mortality. Endovascular interventions and revascularization techniques became more common. The number of surgeries in acute period after aneurysm rupture and hospitals performing more than 50 surgical interventions for cerebral aneurysms annually increased.

Dynamic Mixed-Reality Patient-Specific Aneurysm Clipping Simulation for Two Cases-A Feasibility Study

BACKGROUND AND OBJECTIVE

Intracranial aneurysm (IA) clipping is a complex neurosurgical procedure which demands advanced technology to minimize risks and maximize patient outcomes. This study aims to evaluate the feasibility of training patient-specific microsurgical clipping procedures using a mixed-reality physical neurosurgical simulator for unruptured IA.

METHODS

Two board-certified neurosurgeons were asked to simulate surgery in 2 patient-specific left-side unruptured middle cerebral artery-bifurcation IA models. The study was conducted in the operation theater under realistic conditions using a mixed-reality physical neurosurgical simulator. Time, procedural, and outcome-related information was collected. The participating neurosurgeons were encouraged to attempt all possible clipping strategies, even those deemed suboptimal, reporting the outcome of each strategy. Finally, to evaluate the feasibility and added value of integrating indocyanine green fluorescence angiography (ICG-FA) with the simulator, the ICG-FA videos for each clipping strategy were analyzed and compared with the reported clipping outcomes.

RESULTS

Between 4 and 8, different clipping strategies were applied per aneurysm model; the number of strategies was higher in Patient Model 1 (6.5 ± 1.5) (more complex aneurysm) than in Patient Model 2 (5.0 ± 1.0). The clipping strategies differed between surgeons. At most, 53.5 minutes were necessary to complete each training session, but more than double the time was spent on the more complex aneurysm. Up to 53.8% (Patient Model 1) and 50% (Patient Model 2) of the attempted strategies were discarded by the neurosurgeons during the simulation. Evaluation of aneurysm occlusion through ICG-FA was specific, although sensitivity was poor.

CONCLUSION

The present mixed-reality patient-specific simulator allows testing, anticipating, and discarding different aneurysm microsurgical clipping strategies regardless of the pathology complexity. Specific limitations should be considered regarding ICG-FA aneurysm inspection after clipping.

Dual Microscope Indocyanine Green Video Angiography and Endoscopic Review to Treat Intracranial Aneurysm: A Review of the Literature Regarding a Case

The use of the indocyanine green video angiography (ICG-VA) both endoscope and microscope has become popular in recent decades thanks to the safety, efficacy, and added value that they have provided for cerebrovascular surgery. The dual use of these technologies is considered complementary and has helped cerebrovascular surgeons in decision-making, especially for aneurysm clipping surgery; however, its use has been described for both aneurysm surgery, resection of arteriovenous malformations, or even for bypass surgeries. We conducted a review of the literature with the MeSH terms "microscope indocyanine green video angiography (mICG-VA)," "endoscopic review," AND/OR "intracranial aneurysm." A total of 97 articles that included these terms were selected after a primary review to select a total of 26 articles for the final review. We also present a case to exemplify its use, in which we use both technological tools for the description of the aneurysm, as well as for decision-making at the time of clipping and for reclipping. Both tools, both the use of the endoscope and the mICG-VA, have helped decision-making in neurovascular surgery. A considerable clip replacement rate has been described with the use of these technologies, which has helped to reduce the complications associated with poor clipping. One of the main advantages of their usefulness is that they are tools for intraoperative use, which is why they have shown superiority compared to digital subtraction angiography, which takes longer to use and has a higher risk of complications associated with the contrast medium. On the other hand, a very low rate of complications has been described with the use of the endoscope and mICG-VA, which is why they are considered safe tools to use. In some cases, mention has been made of the use of one or the other technology; however, we consider that its dual use provides more information about the status of the clip, its anatomy, its relationship with other vascular structures, and the complete occlusion of the aneurysm. We consider that the use of both technologies is complementary, so in case of having them both should be used, since both the endoscope and the mICG-VA provide additional and useful information.

A synthetic model simulator for intracranial aneurysm clipping: validation of the UpSurgeOn AneurysmBox

Background and objectives

In recent decades, the rise of endovascular management of aneurysms has led to a significant decline in operative training for surgical aneurysm clipping. Simulation has the potential to bridge this gap and benchtop synthetic simulators aim to combine the best of both anatomical realism and haptic feedback. The aim of this study was to validate a synthetic benchtop simulator for aneurysm clipping (AneurysmBox, UpSurgeOn).

Methods

Expert and novice surgeons from multiple neurosurgical centres were asked to clip a terminal internal carotid artery aneurysm using the AneurysmBox. Face and content validity were evaluated using Likert scales by asking experts to complete a post-task questionnaire. Construct validity was evaluated by comparing expert and novice performance using the modified Objective Structured Assessment of Technical Skills (mOSATS), developing a curriculum-derived assessment of Specific Technical Skills (STS), and measuring the forces exerted using a force-sensitive glove.

Results

Ten experts and eighteen novices completed the task. Most experts agreed that the brain looked realistic (8/10), but far fewer agreed that the brain felt realistic (2/10). Half the expert participants (5/10) agreed that the aneurysm clip application task was realistic. When compared to novices, experts had a significantly higher median mOSATS (27 vs. 14.5; p < 0.01) and STS score (18 vs. 9; p < 0.01); the STS score was strongly correlated with the previously validated mOSATS score (p < 0.01). Overall, there was a trend towards experts exerting a lower median force than novices, however, these differences were not statistically significant (3.8 N vs. 4.0 N; p = 0.77). Suggested improvements for the model included reduced stiffness and the addition of cerebrospinal fluid (CSF) and arachnoid mater.

Conclusion

At present, the AneurysmBox has equivocal face and content validity, and future versions may benefit from materials that allow for improved haptic feedback. Nonetheless, it has good construct validity, suggesting it is a promising adjunct to training.

Comparative outcomes of the treatment of unruptured paraophthalmic aneurysms in the era of flow diversion

BACKGROUND

Paraophthalmic aneurysms present a challenge to surgeons and their ideal management remains up for debate. We studied recent outcomes of these lesions in a single center.

METHODS

A retrospective chart review of all patients undergoing treatment for paraophthalmic aneurysms from 2017-2019 was performed. Factors including patient demographics, aneurysm characteristics, treatment modality, radiographic treatment outcome, clinical outcome, and length of stay were collected, and bivariate analysis was performed.

RESULTS

In total 84.5% (82/97) of aneurysms were treated endovascularly and 15.5% (15/97) surgically. In the surgery cohort, there were three transient perioperative complications (20%) and one minor postoperative complication (6.7%). Complete aneurysm occlusion or near complete (<2mm residual) was achieved in 100% (15/15). All but one patient had mRS ≤1 at the last follow-up. In the endovascular group, 78.1% (64/82) underwent flow diversion alone. Endovascular treatment was associated with a 4.9% (4/82) rate of periprocedural complications: 3 transient events, and 1 death, and a 3.7% (3/82) rate of delayed complications: 2 transient vision changes, and one death. Rate of total occlusion was 87.8% (72/82). 76 patients (92.7%) had mRS ≤1 at the last follow-up. Length of stay was significantly shorter in the endovascular group (3.4 days vs. 7.0 days) [p < 0.001].

CONCLUSIONS

This series demonstrates similar safety to previously reported series as well as the efficacy of both surgical clipping and endovascular embolization of paraophthalmic aneurysms. Rate of complications and treatment efficacy were similar in both groups although this represents a single institution series not generalizable to all centers.

CT advantages of potential use of polymer plastic clips in neurocranium

Aim Clips in neurosurgery are made of titanium alloys, which reduce artifacts on computed tomography (CT). The radiological advantage of plastic clips on the CT image was demonstrated when they were placed in an inter-hemispherical position at an angle of 90º. The aim of this study was to investigate the behaviour of the clip placed at different angles. Methods Sixty heads of domestic pigs were divided into two groups, in group 1 a titanium clip was placed to the interhemispheric position at an angle of 90º, 45º, 0º, ten heads for each angle. In group 2 a plastic clip was placed in the same way. CT scan of the brain was performed for each angle. The size of the density and possible artifact were measured on CT. Results The size of the titanium clip ranged from 17.05 mm at an angle of 0º in the axial plane to 91.47 mm at an angle of 0º in the sagittal plane. The average size of the plastic clip ranged from 6.4 mm at an angle of 0º in the axial plane to 23.22 mm in an angle of 90º in the sagittal plane. Artifacts were observed only in the titanium clip. Conclusion Plastic clips have shown radiological advantages over titanium clips in the CT image. The average density size of the plastic clip in all planes and all angles was smaller than the titanium clip.

Predictive value of neurophysiological monitoring during posterior communicating artery aneurysm clipping for postoperative neurological deficits

Objective

This study aimed to evaluate the diagnostic effect of intraoperative neurophysiological monitoring in identifying intraoperative ischemic events and predicting postoperative neurological dysfunction during PCoA aneurysm clipping, as well as to explore the safe duration of intraoperative temporary clipping of the parent artery.

Methods

All 71 patients with PCoA aneurysm underwent craniotomy and aneurysm clipping. MEP and SSEP were used for monitoring during operation to evaluate the influence of MEP/SSEP changes on postoperative neurological function. Receiver operating characteristic (ROC) curve analysis was used to calculate optimal duration of intraoperative temporary clipping.

Results

Patients with intraoperative MEP/SSEP changes were more likely to develop short-term and long-term neurological deficits than those without MEP/SSEP changes (P < 0.05). From the ROC curve analysis, the safe time from the initiation of temporary clipping during the operation to the early warning of neurophysiological monitoring was 4.5 min (AUC = 0.735, 95%CI 0.5558-0.912). Taking 4.5 min as the dividing line, the incidence of short-term and long-term neurological dysfunction in patients with temporary clipping >4.5 min was significantly higher than that in patients with temporary clipping ≤4.5 min (P = 0.015, P = 0.018).

Conclusion

Intraoperative MEP/SSEP changes are significantly associated with postoperative neurological dysfunction in patients with PCoA aneurysms. The optimal duration of temporary clipping of the parent artery during posterior communicating aneurysm clipping was 4.5 min under neurophysiological monitoring.

Microsurgery for intracranial aneurysms: A qualitative survey on technical challenges and technological solutions

Introduction

Microsurgery for the clipping of intracranial aneurysms remains a technically challenging and high-risk area of neurosurgery. We aimed to describe the technical challenges of aneurysm surgery, and the scope for technological innovations to overcome these barriers from the perspective of practising neurovascular surgeons.

Materials and Methods

Consultant neurovascular surgeons and members of the British Neurovascular Group (BNVG) were electronically invited to participate in an online survey regarding surgery for both ruptured and unruptured aneurysms. The free text survey asked three questions: what do they consider to be the principal technical barriers to aneurysm clipping? What technological advances have previously contributed to improving the safety and efficacy of aneurysm clipping? What technological advances do they anticipate improving the safety and efficacy of aneurysm clipping in the future? A qualitative synthesis of responses was performed using multi-rater emergent thematic analysis.

Results

The most significant reported historical advances in aneurysm surgery fell into five themes: (1) optimising clip placement, (2) minimising brain retraction, (3) tissue handling, (4) visualisation and orientation, and (5) management of intraoperative rupture. The most frequently reported innovation by far was indocyanine green angiography (84% of respondents). The three most commonly cited future advances were hybrid surgical and endovascular techniques, advances in intraoperative imaging, and patient-specific simulation and planning.

Conclusions

While some surgeons perceive that the rate of innovation in aneurysm clipping has been dwarfed in recent years by endovascular techniques, surgeons surveyed highlighted a broad range of future technologies that have the potential to continue to improve the safety of aneurysm surgery in the future.

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

BACKGROUND

Microsurgical clipping of previously coiled intracranial aneurysms can be technically challenging. We present the case of a 48-year-old female with a partially coiled, previously ruptured giant middle cerebral artery aneurysm and the associated technical nuances.

METHODS

We performed a successful coil extraction and clip reconstruction of this aneurysm using an ultrasonic aspirator and stacked fenestrated aneurysm clips.

CONCLUSION

Coil extraction and clip occlusion of previously coiled intracranial aneurysms is a complex and technically challenging procedure but can be performed safely and effectively when employed judiciously.

Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review

During intraoperative monitoring of motor evoked potentials (MEP), heterogeneity across studies in terms of study populations, intraoperative settings, applied warning criteria, and outcome reporting exists. A scoping review of MEP warning criteria in supratentorial surgery was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Sixty-eight studies fulfilled the eligibility criteria. The most commonly used alarm criteria were MEP signal loss, which was always a major warning sign, followed by amplitude reduction and threshold elevation. Irreversible MEP alterations were associated with a higher number of transient and persisting motor deficits compared with the reversible changes. In almost all studies, specificity and Negative Predictive Value (NPV) were high, while in most of them, sensitivity and Positive Predictive Value (PPV) were rather low or modest. Thus, the absence of an irreversible alteration may reassure the neurosurgeon that the patient will not suffer a motor deficit in the short-term and long-term follow-up. Further, MEPs perform well as surrogate markers, and reversible MEP deteriorations after successful intervention indicate motor function preservation postoperatively. However, in future studies, a consensus regarding the definitions of MEP alteration, critical duration of alterations, and outcome reporting should be determined.

Unassisted and multiple microcatheter coiling of distal basilar aneurysms: Outcomes and literature review

PURPOSE

The best treatment for distal basilar artery aneurysms is controversial. We aimed to review our single-centre experience with coil embolisation of aneurysms at this location and compare it with the surgical and endovascular literature.

METHODS

Forty-two aneurysms in a distal basilar location in 42 consecutive patients (15 ruptured and 27 unruptured) were treated endovascularly from 2010 to 2015. Unassisted single and multiple microcatheter coil embolisation alone was used in all cases. We studied our immediate and long-term anatomical results, operative complications, and outcome.

RESULTS

The immediate angiographic results showed complete occlusion in 34 (81%), a neck remnant in seven (16.6%) and a residual aneurysm in one patient (2.4%). There were two thromboembolic events (4.7%) without clinical sequelae; therefore, the operative morbidity and mortality were zero.Three patients with ruptured aneurysms (7.1%) died due to complicated vasospasm. Thirty-nine patients (93%) had clinical and MR imaging follow-up (mean 32.3 months ± 18.6, range from 12 to 66 months). There was recanalization in 30.8% with a retreatment rate of 15.3% and no new bleedings. The aneurysm size was the most important predictor of early anatomical outcome and recurrence.

CONCLUSION

Unassisted and multiple microcatheter coiling is a safe treatment for distal basilar aneurysms. Early anatomical results and recurrence depend on the aneurysm size. Morbidity and mortality are lower and recurrence rates are higher in comparison with clipping or other adjunctive endovascular techniques.

Complications and Neurological Outcome following Intraoperative Aneurysm Rupture in Adult Patients Undergoing Intracranial Aneurysmal Clipping: A Retrospective Study

Background  Intraoperative aneurysmal rupture (IAR) is a catastrophic complication; however, its impact on neurological outcome is debatable. We studied the effects of IAR on intraoperative and postoperative complications and neurological outcome. Methods  In this retrospective study, adult patients who underwent aneurysmal clipping over a period of 2 years were divided as follows: group R (with IAR) and group N (without IAR). Various perioperative parameters, intraoperative and postoperative complications were noted. Glasgow outcome scale (GOS) was noted at discharge from hospital and categorized as favorable (GOS IV and V) and unfavorable (GOS I, II and III). Collected data was statistically analyzed. Univariate and multiple logistic regression analyses were performed to identify predictors of IAR. A p value < 0.05 was considered significant. Results  Thirty-two out of 195 (16.41%) patients suffered IAR, with majority involving anterior communicating artery aneurysm (46.88%). Duration of temporary clipping ( p < 0.001), volume of blood loss, and fluid and blood transfusion were significantly more in group R. Postoperatively, significantly more patients in group R developed intracranial hematoma, cerebral infarct, and required prolonged ventilatory support (≥5 days). Unfavorable neurological outcome was observed more in group R ( p = 0.013). In univariate analysis, blood loss > 500 mL, use of colloids, and duration of surgery > 5 hours were found to be associated with IAR. After multiple logistic regression analysis, only use of colloids and duration of surgery > 5 hours were the most predictive variables for IAR. Conclusions  IAR is associated with serious intraoperative and postoperative complications and unfavorable neurological outcome.

Application of the Endoscopic Micro-Inspection Tool QEVO® in the Surgical Treatment of Anterior Circulation Aneurysms-A Technical Note and Case Series

Introduction: The application of neuro-endoscopes in cerebral aneurysm surgery may help to avoid unintended aneurysm remnants and the accidental clipping of perforating arteries and aid the detection of blood collecting in the subdural spaces. Here, we present our experience with the novel endoscopic micro-inspection tool QEVO® (Carl Zeiss Meditec, Germany) in aneurysm surgery.

Materials and Equipment: In all patients the surgical microscope KINEVO® (Carl Zeiss Meditec, Germany) and the Microinspection tool QEVO® were applied.

Methods: The case series comprises 22 unruptured cerebral aneurysms of the anterior circulation. All aneurysms were treated surgically. All patients routinely underwent computed tomography and digital subtraction angiography within 10 days after surgery.

Results: No aneurysm remnants, cerebral ischemic deficits, or subdural hematomas were detected.

Discussion: In this technical note, we discuss the benefits and limitations of the QEVO® tool and illustrate the major paradigms by means of intraoperative photographs.

Endovascular Temporary Balloon Occlusion for Microsurgical Clipping of Posterior Circulation Aneurysms

Based on the relationship between the posterior clinoid process and the basilar artery (BA) apex it may be difficult to obtain proximal control of the BA using temporary clips. Endovascular BA temporary balloon occlusion (TBO) can reduce aneurysm sac pressure, facilitate dissection/clipping, and finally lower the risk of intraoperative rupture. We present our experience with TBO during aneurysm clipping of posterior circulation aneurysms within the setting of a hybrid operating room (hOR). We report one case each of a basilar tip, posterior cerebral artery, and superior cerebellar artery aneurysm that underwent surgical occlusion under TBO within an hOR. Surgical exposure of the BA was achieved with a pterional approach and selective anterior and posterior clinoidectomy. Intraoperative digital subtraction angiography (iDSA) was performed prior, during, and after aneurysm occlusion. Two patients presented with subarachnoid hemorrhage and one patient presented with an unruptured aneurysm. The intraluminal balloon was inserted through the femoral artery and inflated in the BA after craniotomy to allow further dissection of the parent vessel and branches needed for the preparation of the aneurysm neck. No complications during balloon inflation and aneurysm dissection occurred. Intraoperative aneurysm rupture prior to clipping did not occur. The duration of TBO varied between 9 and 11 min. Small neck aneurysm remnants were present in two cases (BA and PCA). Two patients recovered well with a GOS 5 after surgery and one patient died due to complications unrelated to surgery. Intraoperative TBO within the hOR is a feasible and safe procedure with no additional morbidity when using a standardized protocol and setting. No relevant side effects or intraoperative complications were present in this series. In addition, iDSA in an hOR facilitates the evaluation of the surgical result and 3D reconstructions provide documentation of potential aneurysm remnants for future follow-up.

Effect of Pregabalin on Perioperative Headache in Patients with Aneurysmal Subarachnoid Hemorrhage: A Randomized Double-Blind, Placebo-Controlled Trial

Background Patients with acute aneurysmal subarachnoid hemorrhage (aSAH) experience excruciating headache that is difficult to manage in resource-constrained settings. Pregabalin’s (β-isobutyl-GABA) analgesic, antiepileptic, and antiemetic properties make it an attractive adjuvant in pain management for these patients.

Methods We conducted a double-blind, placebo-controlled, randomized clinical trial on 40 aSAH patients undergoing aneurysmal clipping to assess the effect of perioperative pregabalin in decreasing perioperative headache, anesthetic, and opioid requirement. Patients received either pregabalin (75 mg) or placebo twice daily soon after admission till 24-hour postoperative, in addition to paracetamol 650 mg thrice daily. Headache assessed using a visual analog scale (VAS) at five time points was compared using a mixed effects regression model.

Results Pain assessed by VAS declined significantly more from the baseline in pregabalin recipients compared with placebo at preinduction (–3.6 vs.–1.8; p = 0.004), 12-hour (4.3 vs. 2.8; p = 0.014), and 24-hour postsurgery (4.7 vs. 2.9; p = 0.007), but not at the 6-hour postoperation (4.9 vs. 3.8; p = 0.065). Pregabalin recipients required a lower minimum alveolar concentration of sevoflurane to maintain a prespecified bispectral index of 40 and 60 (0.8 vs. 0.9; p = 0.014) and required fewer rescue analgesic doses in the 24  hours following surgery (1.8 vs. 3.3; p = 0.005). The intraoperative fentanyl requirement was not significantly different between the groups (10 μg/kg vs. 11.4 μg/kg; p = 0.065). There was no significant difference in the sedation scores.

Conclusions Pregabalin 75 mg administered twice daily, during the perioperative period, was an effective adjunct in the management of the severe headache experienced by patients with aSAH and decreased the opioid and anesthetic requirement without significantly increasing sedation.

Development and validation of the Skills Assessment in Microsurgery for Brain Aneurysms (SAMBA) instrument for predicting proficiency in aneurysm surgery

OBJECTIVE

Surgical performance evaluation was first described with the OSATS (Objective Structured Assessment of Technical Skills) and modified for aneurysm microsurgery simulation with the OSAACS (Objective Structured Assessment of Aneurysm Clipping Skills). These methods rely on the subjective opinions of evaluators, however, and there is a lack of objective evaluation for proficiency in the microsurgical treatment of brain aneurysms. The authors present a new instrument, the Skill Assessment in Microsurgery for Brain Aneurysms (SAMBA) scale, which can be used similarly in a simulation model and in the treatment of unruptured middle cerebral artery (MCA) aneurysms to predict surgical performance; the authors also report on its validation.

METHODS

The SAMBA scale was created by consensus among 5 vascular neurosurgeons from 2 different neurosurgical departments. SAMBA results were analyzed using descriptive statistics, Cronbach's alpha indexes, and multivariate ANOVA analyses (p < 0.05).

RESULTS

Expert, intermediate-level, and novice surgeons scored, respectively, an average of 33.9, 27.1, and 16.4 points in the real surgery and 33.3, 27.3, and 19.4 points in the simulation. The SAMBA interrater reliability index was 0.995 for the real surgery and 0.996 for the simulated surgery; the intrarater reliability was 0.983 (Cronbach's alpha). In both the simulation and the real surgery settings, the average scores achieved by members of each group (expert, intermediate level, and novice) were significantly different (p < 0.001). Scores among novice surgeons were more diverse (coefficient of variation = 12.4).

CONCLUSIONS

Predictive validation of the placenta brain aneurysm model has been previously reported, but the SAMBA scale adds an objective scoring system to verify microsurgical ability in this complex operation, stratifying proficiency by points. The SAMBA scale can be used as an interface between learning and practicing, as it can be applied in a safe and controlled environment, such as is provided by a placenta model, with similar results obtained in real surgery, predicting real surgical performance.

Microsurgical clipping of an unruptured superiorly projecting ACoM aneurysm in a rotated ACoM complex

This case illustrates surgical technique for wide neck aneurysm clipping in a rotated complex and how to manage intraoperative aneurysm rupture while maintaining hemostasis (Cai et al., Anterior communicating artery aneurysm morphology and the risk of rupture. World Neurosurg. 2018;109:119 and Dehdashti et al., The implication of anterior communicating complex rotation and 3-dimensional computerized tomography angiography findings in surgical approach to anterior communicating artery aneurysms. World Neurosurg. 2016;91:34).

Anatomical triangles defining routes to anterior communicating artery aneurysms: the junctional and precommunicating triangles and the role of dome projection

OBJECTIVE

Anterior communicating artery (ACoA) aneurysms are common intracranial aneurysms. Despite advances in endovascular therapy, microsurgical clipping remains an important treatment for aneurysms with broad necks, large size, intraluminal thrombus, complex branches, or previous coiling. Anatomical triangles identify safe corridors for aneurysm access. The authors introduce the A1-A2 junctional triangle and the A1-A1 precommunicating triangle and examine relationships between dome projection, triangular corridors of access, and surgical outcomes.

METHODS

Preoperative catheter and CT angiograms were evaluated to characterize aneurysm dome projection. Aneurysm projection was categorized into quadrants and octants. Preoperative, intraoperative, and postoperative factors were correlated to aneurysm dome projection and patient outcomes using univariate and multivariate analyses.

RESULTS

A total of 513 patients with microsurgically treated ACoA aneurysms were identified over a 13-year period, and 400 had adequate imaging and follow-up data for inclusion. Surgical clipping was performed on 271 ruptured and 129 unruptured aneurysms. Good outcomes were observed in 91% of patients with unruptured aneurysms and 86% of those with ruptured aneurysms, with a mortality rate < 1% among patients with unruptured aneurysms. Increasing age (p < 0.01), larger aneurysm size (p = 0.03), and worse preoperative modified Rankin Scale score (p < 0.01) affected outcomes adversely. Aneurysms projecting superiorly and posteriorly required dissection in the junctional triangle, and multivariate analysis demonstrated worse clinical outcomes in these patients (p < 0.01).

CONCLUSIONS

Anteriorly and inferiorly projecting aneurysms involve only the precommunicating triangle, are simpler to treat microsurgically, and have more favorable outcomes. Superior and posterior dome projections make ACoA aneurysms more difficult to visualize and require opening the junctional triangle. Added visualization through the junctional triangle is recommended for these aneurysms in order to facilitate dissection of efferent branch arteries, careful clip application, and perforator preservation. Dome projection can be determined preoperatively from images and can help anticipate dissection routes through the junctional triangle.

The Morphological and Hemodynamic Characteristics of the Intraoperative Ruptured Aneurysm

Background and Objectives

Intraoperative aneurysm rupture (IOR) is a difficult event during the clipping process for intracranial aneurysms, and could result in a bad prognosis. Preoperative discrimination of aneurysms with high risk of IOR is vital for operators. The aim of this study was to explore the hemodynamic-morphological risk factors for the IOR.

Methods

In the present study, patients admitted for unruptured IA from January 2012 to April 2018 were retrospectively reviewed. A propensity score matching was performed to match patients. The morphological features and the hemodynamic features were extracted. Differences in the morphologic and hemodynamic parameters were compared. Risk factors associated with IOR were explored. Subsequently, the hemodynamic characteristics in different rupture stages and different regions in IOR aneurysm were compared.

Results

96 cases of patients with aneurysms, were found by the matching process in each group. The statistically significant difference was found in the maximum length (L) (p = 0.041), maximum diameter of body (D) (p = 0.032), aspect ratio (AR) (p < 0.001), non-sphericity index (NSI) (p < 0.001), normalized wall shear stress maximum (NWSSm) (p < 0.001) and oscillatory shear index (OSI) (p < 0.001). A regression analysis demonstrated AR (OR = 7.03, p < 0.001), NWSSm (OR = 15.55, p = 0.014) and OSI (OR = 28.30, p < 0.001) as the independent risk factors for IOR. AR was much larger, and NWSSm and NWSSa were much lower for IAs that ruptured in early or pre-dissection stage than those for IAs that ruptured in dissection stage or clip application stage. NWSSa and NWSSm in rupture area were both lower than those in adjacent area.

Conclusion

AR, NWSSm, and OSI are considered three independent risk factors for intraoperative aneurysm rupture, which could serve as predictors. A selection of intervention methods for aneurysms with high AR, low NWSSm, and high OSI should carefully be considered.

Delayed Rupture of a Cortical Traumatic Intracranial Aneurysm

Traumatic intracranial aneurysms are rare lesions that occur after blunt or primarily penetrating mechanisms. These are extremely fragile vessel injuries associated with significant morbidity and mortality, especially after rupture. Disease natural history, surveillance strategies, and management are based on small case series. Here we present a case of a 29-year-old male with a large epidural hematoma after blunt trauma, who underwent emergent surgical intervention. Three months postoperatively, he presented with unusual cerebral bleeding. Clinical suspicion prompted a conventional angiogram, which diagnosed a ruptured cortical traumatic intracranial aneurysm. The patient was urgently treated by surgical clipping with a good outcome.

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.

[Surgical treatment of cerebral aneurysms in the Russian Federation]

OBJECTIVE

The objective of this study was to evaluate the results of surgical treatment of cerebral aneurysms in the Russian Federation.

MATERIAL AND METHODS

We analyzed performance indicators in neurosurgical departments of regional and federal health institutions of the Russian Federation for 2017. The results of surgical treatment of cerebral aneurysms (CAs) were analyzed in 19 regional vascular centers (RVCs) in several federal districts and in 3 federal centers (FCs) with the most dynamically developing vascular neurosurgery and smoothly running system of statistical data processing.

RESULTS

The study included 3160 patients hospitalized to 22 medical institutions in 2017. Of these, 1808 patients were treated in RVCs, and 1352 patients were treated in FCs. We analyzed factors affecting the treatment outcome in CA patients. We identified features of CA treatment in clinics with a different amount of surgical intervention.

CONCLUSION

An increase in the surgical activity in centers and simultaneous development of microsurgical and endovascular treatments for cerebral aneurysms reduce postoperative mortality. Due to the presence of a RVC network in the Russian Federation, many patients could receive necessary specialized treatment. The number of operations for cerebral aneurysms has increased 6-fold for the past 10 years.

Training in Cerebral Aneurysm Clipping Using Self-Made 3-Dimensional Models

INTRODUCTION

Recently, there have been increasingly fewer opportunities for junior surgeons to receive on-the-job training. Therefore, we created custom-built three-dimensional (3D) surgical simulators for training in connection with cerebral aneurysm clipping.

METHODS

Three patient-specific models were composed of a trimmed skull, retractable brain, and a hollow elastic aneurysm with its parent artery. The brain models were created using 3D printers via a casting technique. The artery models were made by 3D printing and a lost-wax technique. Four residents and 2 junior neurosurgeons attended the training courses. The trainees retracted the brain, observed the parent arteries and aneurysmal neck, selected the clip(s), and clipped the neck of an aneurysm. The duration of simulation was recorded. A senior neurosurgeon then assessed the trainee's technical skill and explained how to improve his/her performance for the procedure using a video of the actual surgery. Subsequently, the trainee attempted the clipping simulation again, using the same model. After the course, the senior neurosurgeon assessed each trainee's technical skill. The trainee critiqued the usefulness of the model and the effectiveness of the training course.

RESULTS

Trainees succeeded in performing the simulation in line with an actual surgery. Their skills tended to improve upon completion of the training.

CONCLUSION

These simulation models are easy to create, and we believe that they are very useful for training junior neurosurgeons in the surgical techniques needed for cerebral aneurysm clipping.

Dual Endoscopic Endonasal Transsphenoidal and Precaruncular Transorbital Approaches for Clipping of the Cavernous Carotid Artery: A Cadaveric Simulation

Background Endoscopic skull base approaches are being used to address complicated neurovascular pathology. These approaches are safest when proximal vascular control of the cavernous carotid artery (CavCA) can be obtained. Methods We present a cadaver-based anatomic simulation study showing the feasibility of clip placement for the CavCA as it courses through the cavernous sinus. The arterial vessels were injected with red microfil (Flow Tech, Carver, Massachusetts) to enhance visibility. The endoscope was directed through a precaruncular transorbital approach and instrumentation was managed through an endonasal transsphenoidal approach. Results The dual approach minimized the "coning down" and instrument "sword fighting" that occurs as the rod lens endoscope and instruments are used laterally and posterior toward the clivus and brainstem. The precaruncular transorbital approach improved visualization of the clip application and improved the functional working area. The transorbital port allowed better appreciation of the distal clip tines, and the laterally positioned cranial nerves. Conclusions The advantages may be most realized in the setting of endoscopic endonasal resection of highly vascular lesions and/or bleeding from a ruptured aneurysm being clipped. Simulated training provides an excellent opportunity to enhance skill sets and increase familiarity with anatomical visualization before entering the operative arena.

Factors influencing management of unruptured intracranial aneurysms: an analysis of 424 consecutive patients

OBJECTIVE The choice between treating and observing unruptured intracranial aneurysms is often difficult, with little guidance on which variables should influence decision making on a patient-by-patient basis. Here, the authors compared demographic variables, aneurysm-related variables, and comorbidities in patients who received microsurgical or endovascular treatment and those who were conservatively managed to determine which factors push the surgeon toward recommending treatment. METHODS A retrospective chart review was conducted of all patients diagnosed with an unruptured intracranial aneurysm at their institution between January 1, 2013, and January 1, 2016. These patients were dichotomized based on whether their aneurysm was treated. Demographic, geographic, socioeconomic, comorbidity, and aneurysm-related information was analyzed to assess which factors were associated with the decision to treat. RESULTS A total of 424 patients were identified, 163 who were treated surgically or endovascularly and 261 who were managed conservatively. In a multivariable model, an age < 65 years (OR 2.913, 95% CI 1.298-6.541, p = 0.010), a lower Charlson Comorbidity Index (OR 1.536, 95% CI 1.274-1.855, p < 0.001), a larger aneurysm size (OR 1.176, 95% CI 1.100-1.257, p < 0.001), multiple aneurysms (OR 2.093, 95% CI 1.121-3.907, p = 0.020), a white race (OR 2.288, 95% CI 1.245-4.204, p = 0.008), and living further from the medical center (OR 2.125, 95% CI 1.281-3.522, p = 0.003) were all associated with the decision to treat rather than observe. CONCLUSIONS Whereas several factors were expected to be considered in the decision to treat unruptured intracranial aneurysms, including age, Charlson Comorbidity Index, aneurysm size, and multiple aneurysms, other factors such as race and proximity to the medical center were unanticipated. Further studies are needed to identify such biases in patient treatment and improve treatment delineation based on patient-specific aneurysm rupture risk.

Remote cerebellar haemorrhage from site of craniotomy: A report of two cases

Remote cerebellar haemorrhage (RCH) is a rare complication of neurosurgical procedures seldom requiring intervention. We report two cases of RCH. The first unilateral RCH is asymptomatic, the other is bilateral and associated with supratentorial haemorrhage and hydrocephalus requiring intervention. We propose multiple foci of haemorrhage as an adverse prognostic marker in RCH.

Clipping of a ruptured anterior communicating artery aneurysm with right A1-A2 sectioning and reanastomosis

We showcase the microsurgical clipping of a previously coiled and ruptured anterior communicating artery aneurysm, done through a right-sided approach. Initial clipping with a fenestrated clip occluded the flow in the right A2. After temporary clipping of both A1 and A2 vessels, we cut the right A1 and A2, clipped the aneurysm with a straight clip while preserving the flow in the left A1 and A2 and then performed reanastomosis of the right A1-A2 in an end to end fashion. This strategy allowed for complete obliteration of the aneurysm while preserving the flow in all four vessels. The video can be found here: http://youtu.be/4Y024zU5NVo.

Surgical clipping of a ruptured posterior inferior cerebellar artery aneurysm

Posterior circulation aneurysms are commonly treated with endovascular techniques. In select cases, microsurgery remains an essential tool for treating these lesions. We present a case of a ruptured posterior inferior cerebellar artery (PICA) aneurysm approached via a craniotomy. Given the labyrinth of neurovascular bundles present in the posterior fossa, surgical exposure of PICA aneurysms can be challenging. This video demonstrates the steps of the craniotomy, subarachnoid dissection, mobilization of the vertebral artery and lower cranial nerves, and clipping of the aneurysm. The video can be found here: http://youtu.be/fQSxQj7oL0U .

Surgical clipping of a large left middle cerebral artery aneurysm

Middle cerebral artery aneurysms, especially those with complex morphology, are considered excellent aneurysms for surgical clipping, given the challenges that exist with current endovascular techniques. We present a case of a large, complex, left middle cerebral artery aneurysm treated with microsurgical clipping. This video highlights critical steps in obtaining proximal and distal control as well as subarachnoid dissection necessary to prepare the aneurysm for final clipping. The video can be found here: http://youtu.be/RlKH2Km9z5Y .