Statistical evaluation of measured biomechanical properties of human brain aneurysm samples.

Background and purpose:

Human brain aneurysms may often prove fatal if not re­cognized in time and treated accordingly. The understanding of development and rupture of aneurysms can significantly be improved by the application of numerical modelling, which in turn, requires the knowledge of mechanical properties of vessel wall. This study aims to identify assumed differences with respect to age, sex, spatial orientation, and rupture by utilizing detailed statistical analysis of uniaxial tensile measurements of human brain aneurysm samples, performed by the authors in a previous project.

At surgery of 42 patients, aneu­rysm fundi were cut distally to the clip. In each case, depending on size, varying number of stripes (altogether 88) were prepared and uniaxial stress-strain measurements were performed. Quantities related to the capacity, energy absorption or stiffness were determined and statistically analysed.

The number of specimens in the aneurysm sample was sufficient to establish statistical differences with respect to sex and rupture (p<0.05). No significant differences were detected in orientation, though higher values of stresses and deformations were ob­tained in the circumferential direction com­pared to the meridional direction. 

Significant differences bet­ween sexes with respect to ultimate deformations were demonstrated according to expectation, and the hypothesis on equality of energy capacity could be supported. Similarity of curves with respect to specimen orientation was also observed and ruptured aneurysm sacs tended to be smaller in size. It seems that differences and trends described in this paper are realistic and need to be applied in numerical modelling.

Improved rates of postoperative ischemia, completeness of aneurysm occlusion and neurological deficits in elective clipping of anterior circulation aneurysms over the past 20 years - association with technical improvements.

BACKGROUND/PURPOSE: Several periprocedural adjuncts for elective surgical aneurysm treatment have been introduced over the last 20 years to increase safety and efficacy. Besides the introduction of IONM in the late-1990s, ICG-videoangiography (ICG-VAG) since the mid-2000s and intraoperative CT-angiography/-perfusion (iCT-A/-P) since the mid-2010s are available. We aimed to clarify whether the introduction of ICG-VAG and iCT-A/-P resulted in our department in a stepwise improvement in the rate of radiologically detected postoperative ischemia, complete aneurysm occlusion and postoperative new deficits. METHODS: Patients undergoing microsurgical clip occlusion for unruptured anterior circulation aneurysms between 2000 and 2019 were included, with ICG-VAG since 2009 and iCT-A/-P (for selected cases) since 2016. Baseline characteristics and treatment-related morbidity/outcome focusing on differences between the three distinct cohorts (cohort-I: pre-ICG-VAG-era, cohort-II: ICG-VAG-era, cohort-III: ICG-VAG&iCT-A/-P-era) were analyzed. RESULTS: 1391 patients were enrolled (n = 74 were excluded), 779 patients were interventionally treated, 538 patients were surgically clipped by a specialized vascular team (cohort-I n = 167, cohort-II n = 284, cohort-III n = 87). Aneurysm size was larger in cohort-I (8.9 vs. 7.5/6.8 mm; p < 0.01) without differences concerning age (mean:55years), gender distribution (m: f = 1:2.6) and aneurysm location (MCA:61%, ICA:18%, ACA/AcomA:21%). There was a stepwise improvement in the rate of radiologically detected postoperative ischemia (16.2vs.12.0vs.8.0%; p = 0.161), complete aneurysm occlusion (68.3vs.83.6vs.91.0%; p < 0.01) and postoperative new deficits (10.8vs.7.7vs.5.7%; p = 0.335) from cohort-I to -III. After a mean follow-up of 12months, a median modified Rankin scale of 0 was achieved in all cohorts. DISCUSSION: Associated with periprocedural technical achievements, surgical outcome in elective anterior circulation aneurysm surgery has improved in our service during the past 20 years.

Efficacy and safety of adenosine, rapid ventricular pacing and hypothermia in cerebral aneurysms clipping: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: Cerebral aneurysms in complex anatomical locations and intraoperative rupture can be challenging. Many methods to reduce blood flow can facilitate its exclusion from the circulation. This study evaluated the safety and efficacy of using adenosine, rapid ventricular pacing, and hypothermia in cerebral aneurysm clipping. METHODS: Databases (PubMed, Embase, and Web of Science) were systematically searched for studies documenting the use of adenosine, rapid ventricular pacing, and hypothermia in cerebral aneurysm clipping and were included in this single-arm meta-analysis. The primary outcome was 30-day mortality. Secondary outcomes included neurological outcomes by mRs and GOS, and cardiac outcomes. We evaluated the risk of bias using ROBIN-I, a tool developed by the Cochrane Collaboration. OpenMetaAnalyst version 2.0 was used for statistical analysis and I2 measured data heterogeneity. Heterogeneity was defined as an I2 > 50%. RESULTS: Our systematic search yielded 10,100 results. After the removal of duplicates and exclusion by title and abstract, 64 studies were considered for full review, of which 29 were included. The overall risk of bias was moderate. The pooled proportions of the adenosine analysis for the different outcomes were: For the primary outcome: 11,9%; for perioperative arrhythmia: 0,19%; for postoperative arrhythmia: 0,56%; for myocardial infarction incidence: 0,01%; for follow-up good recovery (mRs 0-2): 88%; and for neurological deficit:14.1%. In the rapid ventricular pacing analysis, incidences were as follows: peri operative arrhythmia: 0,64%; postoperative arrhythmia: 0,3%; myocardial infarction: 0%. In the hypothermia analysis, the pooled proportion of 30-day mortality was 11,6%. The incidence of post-op neurological deficits was 35,4% and good recovery under neurological analysis by GOS was present in 69.2%. CONCLUSION: The use of the three methods is safe and the related complications were very low. Further studies are necessary, especially with comparative analysis, for extended knowledge.

Letter to editor: Bridging the gap: robotic applications in cerebral aneurysms neurointerventions - a systematic review.

The letter critically evaluates the role of robotic applications in cerebral aneurysm neurointerventions, synthesizing a diverse array of studies to elucidate both the potential benefits and inherent limitations of this emerging technology. The review highlights the advancements in precision, efficiency, and patient outcomes facilitated by robotic platforms, while also acknowledging challenges such as the steep learning curve and the need for further research to establish long-term efficacy and cost-effectiveness. By navigating through the complexities of robotic-assisted neurosurgery, the review provides valuable insights into the transformative potential of robotics in optimizing treatment paradigms and improving patient care.

Quantitative analysis of hemodynamic changes induced by the discrepancy between the sizes of the flow diverter and parent artery.

The efficacy of flow diverters is influenced by the strut configuration changes resulting from size discrepancies between the stent and the parent artery. This study aimed to quantitatively analyze the impact of size discrepancies between flow diverters and parent arteries on the flow diversion effects, using computational fluid dynamics. Four silicone models with varying parent artery sizes were developed. Real flow diverters were deployed in these models to assess stent configurations at the aneurysm neck. Virtual stents were generated based on these configurations for computational fluid dynamics analysis. The changes in the reduction rate of the hemodynamic parameters were quantified to evaluate the flow diversion effect. Implanting 4.0 mm flow diverters in aneurysm models with parent artery diameters of 3.0-4.5 mm, in 0.5 mm increments, revealed that a shift from oversized to undersized flow diverters led to an increase in the reduction rates of hemodynamic parameter, accompanied by enhanced metal coverage rate and pore density. However, the flow diversion effect observed transitioning from oversizing to matching was less pronounced when moving from matching to undersizing. This emphasizes the importance of proper sizing of flow diverters, considering the benefits of undersizing and not to exceed the threshold of advantages.

Microsurgical treatment of ophthalmic artery aneurysm, a case series of 55 patients with long-term follow-up.

BACKGROUND: Ophthalmic artery aneurysm (OAA) can be secured in endovascular or microsurgical approaches. Still there are controversies in technique selection and their long term outcomes. METHODS: All the patients with OAA were treated microsurgically and followed. Demographic data, neurological status, physical examination findings, angiographic data, operation details, and intraoperative and postoperative events were recorded and analyzed. P < 0.05 was considered significant. RESULTS: Among 55 patients, 38 were females (69.1%). Median preoperative glasgow coma scale (GCS), Fisher Grade, and Hunt and Hess(HH) scores were 15, 1 and 1, respectively. The most common neurologic manifestation was visual problems (n = 15). The most common anatomical projection was medial (43.6%) oriented lesions. 85.5% of them only had 1 ophthalmic aneurysm while multiple aneurysms were reported in 14.6%. In 52 patients temporary clip was used. in 21 patients (38.2%) intraoperative aneurysm rupture occurred. Larger aneurysm size and preoperative hydrocephalus were associated with higher rates of aneurysm rupture (P = 0.003 and 0.031). 28.5% of the patients with visual problems had clinical improvement in the postoperative period. The mean follow-up period was 5 years. Follow-up angiography showed a 100% obliteration rate with a 0.0% recurrence rate. Median values for follow-up glasgow outcome scale and modified Rankin scale were 5 and 0, respectively. favorable neurological outcomes were associated with better primary GCS and HH scores. CONCLUSION: OAA microsurgery is an effective and safe procedure with significant improvement in both visual and neurological status. Low recurrence rate and excellent clinical recovery are the most important advantages of microsurgery in OAA treatment.

Management of Incidental Carotid Cave Aneurysm.

BACKGROUND: Incidental diagnosis of saccular aneurysms is more common with the advent of imaging techniques. Because of the severe morbidity and mortality that they can cause, treatment is chased for them, either microsurgical treatment or endovascular, even when they are diagnosed incidentally. Carotid cave aneurysms are rare, and they seem to have a more benign course compared to other intracranial aneurysms, probably related to the physical enveloping effect of the surrounding structures. Yet, their microsurgical treatment is a serious challenge technically for the neurosurgeon, with its severe morbidity and mortality for the patient. Endovascular techniques have their risks, too. PURPOSE: In this paper, we analyzed and presented our series of incidentally diagnosed carotid cave aneurysms. MATERIALS AND METHODS: The age, gender of patients, the size, laterality, and MR angiographic follow-up of aneurysms were reported. Their clinical results were noted. RESULTS: Fifty-six patients who had incidentally been diagnosed with 59 carotid cave aneurysms were followed up. No patient was microsurgically treated, but 15 patients had endovascular treatment for 15 aneurysms. The mean size of 15 treated aneurysms was 4.6 ± 2.1 (range = 2-10) mm, and it was 3.0 ± 1.5 (range = 1.7-10) mm for the untreated aneurysms (n = 44). There was no significant difference between the follow-up times of the treated and untreated groups (P = 0.487). The median follow-up of 59 aneurysms in 56 patients was 52 (mean = 49.6 ± 27.9, range = 1-124) months, with a total follow-up of 244 aneurysm years. None of the patients had subarachnoid hemorrhage related to carotid cave aneurysms during follow-up, and none of the aneurysms had shown growth. Two patients who had endovascular treatment had ischemic complications with minor neurologic deficits. CONCLUSION: Follow-up can be a reasonable option for the incidental aneurysms that are located and confined to the carotid cave. Additionally, TOF might be a reliable method for follow-up imaging of carotid cave aneurysms.

Advances in the Endovascular Management of Cerebrovascular Disease.

The field of endovascular neurosurgery has experienced remarkable progress over the last few decades. Endovascular treatments have continued to gain traction as the advancement of technology, technique, and procedural safety has allowed for the expansion of treatment indications of various cerebrovascular pathologies. Interventions such as the coiling of intracranial aneurysms, carotid artery stenting, mechanical thrombectomy in the setting of ischemic stroke, and endovascular embolization of arteriovenous malformations have all seen transformations in their safety and efficacy, expanding the scope of endovascularly treatable conditions and offering new hope to patients who may have otherwise not been candidates for surgical intervention. Despite this notable progress, challenges persist, including complications associated with device deployment and questions regarding long-term outcomes. This article explores the advancements in endovascular neurosurgical techniques, highlighting the impact on patient care, outcomes, and the evolution of traditional surgical methods.

Spontaneous occlusion of ruptured microaneurysm formed on postoperative transosseous anastomosis after indirect revascularization in a patient with moyamoya disease.

A 40-year-old female with a history of ischemic moyamoya disease treated with indirect revascularization at ages 12 and 25 years presented with a sudden severe headache. Imaging studies revealed focal parenchymal hemorrhage and acute subdural hematoma, confirming a microaneurysm formed on the postoperative transosseous vascular network as the source of bleeding. Conservative management was performed, and no hemorrhage recurred during the 6-month follow-up period. Interestingly, follow-up imaging revealed spontaneous occlusion of the microaneurysm. However, due to the rarity of this presentation, the efficacy of conservative treatment remains unclear. Further research on similar cases is warranted.

Safety and efficacy of stent-assisted coil embolization with periprocedural dual antiplatelet therapy for the treatment of acutely ruptured intracranial aneurysms.

PURPOSE: Despite growing evidence for the effectiveness of stent-assisted coil embolization (SAC) in treating acutely ruptured aneurysms, the safety of stent placement in acute phase remains controversial because of concerns for stent-induced thromboembolism and hemorrhagic events attributable to the necessity of antiplatelet therapy. Therefore, we investigated the safety and efficacy of SAC with periprocedural dual antiplatelet therapy (DAPT) compared with the coiling-only technique to determine whether it is a promising treatment strategy for ruptured aneurysms. METHODS: We retrospectively evaluated 203 enrolled patients with acutely ruptured aneurysms, categorizing them into two groups: SAC and coiling-only groups. Comparative analyses between the two groups regarding angiographic results, clinical outcomes, and procedure-related complications were performed. A subgroup analysis of procedural complications was conducted on patients who did not receive chronic antithrombotic medications to alleviate their influence before hospitalization. RESULTS: 130 (64.0%) patients were treated using the coiling-only technique, whereas 73 (36.0%) underwent SAC. There was a trend to a higher complete obliteration rate (p = 0.061) and significantly lower recanalization rate (p = 0.030) at angiographic follow-up in the SAC group compared to the coiling-only group. Postprocedural cerebral infarction occurred less frequently in the SAC group (8.2%) than in the coiling-only group (17.7%), showing a significant difference (p = 0.044). Although the ventriculostomy-related hemorrhage rate was significantly higher in the SAC group than in the coiling-only group (26.2% vs. 9.3%, p = 0.031), the incidence of symptomatic ventriculostomy-related hemorrhage was comparable. Subgroup analysis excluding patients receiving chronic antithrombotic medications showed similar results. CONCLUSION: SAC with periprocedural DAPT could be a safe and effective treatment strategy for acutely ruptured aneurysms. Moreover, it might have a protective effect on postprocedural cerebral infarction without increasing the risk of symptomatic hemorrhagic complications.

Risk factors for cerebral edema following aneurysm clipping in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVES: To investigate the factors that contribute to the development of cerebral edema after aneurysm clipping in individuals with aneurysmal subarachnoid hemorrhage (aSAH). METHODS: A total of 232 patients with aSAH caused by rupture and treated with aneurysm clipping were included in the retrospective analysis of clinical data. Postoperatively, the participants were categorized into two groups based on the presence or absence of cerebral edema: a complication group (n=33) and a non-complication group (n=199).A comparison was made between the overall data of the 2 groups. RESULTS: In the complication group, there were higher proportions of patients experiencing recurrent bleeding, aneurysm in the posterior circulation, Fisher grade III-IV, World Federation of Neurosurgical Societies (WFNS) grade II, Hunt-Hess grade III-IV, concomitant hypertension, duration from onset to operation ≥12 h, and concomitant hematoma compared to the non-complication group (p<0.05). Cerebral edema after aneurysm clipping was associated with several risk factors including repeated bleeding, aneurysm in the back of the brain, Fisher grade III-IV, WFNS grade II, Hunt-Hess grade III-IV, simultaneous high blood pressure and hematoma, and a duration of at least 12 hours from the start of symptoms to the surgical procedure (p<0.05). CONCLUSION: In patients with aSAH, the risk of cerebral edema after aneurysm clipping is increased by recurrent bleeding, aneurysm in the posterior circulation, Fisher grade III-IV, WFNS grade II, Hunt-Hess grade III-IV, concomitant hypertension and hematoma, and duration of ≥12 h from onset to operation.

Evaluation of Hemodynamic Alterations after Flow Diverter Placement using the AneurysmFlowTM tool.

Background: AneurysmFlow (Phillips Healthcare) is the flow measurement tool, utilizing an optical flow-based algorithm from DSA, lacks sufficient published studies. This study aimed to assess the significance of flow velocity changes and the Mean Aneurysm Flow Amplitude (MAFA) ratio in evaluating outcomes following flow-diverting treatments. Methods: Between June 2021 and October 2022, 41 patients with 42 aneurysms underwent FDS treatment with AneurysmFlow measu-rement at the Bach Mai Radiology Center. Results: The tool achieved a 90.5% success rate in 38 out of 42 patients. Most aneurysms (89.5%) were small to medium-sized (<10 mm), and a decrease in flow velocity post-stent deployment was ob-served in 78.9% of cases. Conversely, 21.1% showed increased flow, mainly in aneurysms smaller than 5 mm. No significant association was found between flow changes or MAFA ratio and aneurysm size characteristics. Twenty-two patients (59.5%) underwent re-examination at 6 months, revealing no correlation in MAFA ratio between completely and incompletely occluded aneurysms. Conclusions: Our current investigation, primarily centered on small and medium-sized aneurysms, did not uncover any link between quantitative flow changes assessed using the AneurysmFlow software and the occlusion status of aneurysms at the 6-month follow-up post-flow diverter treatment. Larger case series with extended follow-up imaging are necessary to further explore these findings.

Intracranial pressure following surgery of an unruptured intracranial aneurysm-a model for normal intracranial pressure in humans.

OBJECTIVE: Optimizing the treatment of several neurosurgical and neurological disorders relies on knowledge of the intracranial pressure (ICP). However, exploration of normal ICP and intracranial pressure pulse wave amplitude (PWA) values in healthy individuals poses ethical challenges, and thus the current documentation remains scarce. This study explores ICP and PWA values for healthy adults without intracranial pathology expected to influence ICP. METHODS: Adult patients (age > 18 years) undergoing surgery for an unruptured intracranial aneurysm without any other neurological co-morbidities were included. Patients had a telemetric ICP sensor inserted, and ICP was measured in four different positions: supine, lateral recumbent, standing upright, and 45-degree sitting, at day 1, 14, 30, and 90 following the surgery. RESULTS: ICP in each position did not change with time after surgery. Median ICP was 6.7 mmHg and median PWA 2.1 mmHg in the supine position, while in the upright standing position median ICP was - 3.4 mmHg and median PWA was 1.9 mmHg. After standardization of the measurements from the transducer site to the external acoustic meatus, the median ICPmidbrain was 8.3 mmHg in the supine position and 1.2 mmHg in the upright standing position. CONCLUSION: Our study provides insights into normal ICP dynamics in healthy adults following a uncomplicated surgery for an unruptured aneurysm. These results suggest a slightly wider normal reference range for invasive intracranial pressure than previously suggested, and present the first normal values for PWA in different positions. Further studies are, however, essential to enhance our understanding of normal ICP. Trial registration The study was preregistered at www. CLINICALTRIALS: gov (NCT03594136) (11 July 2018).