Impact of Aneurysm Shape on Intraoperative Rupture During Clipping of Ruptured Intracranial Aneurysms

Clinical relevance of critical plasma homocysteine levels in predicting rupture risk for small and medium-sized intracranial aneurysms

Plasma homocysteine (Hcy) has been globally recognized as an independent risk factor for various neurovascular diseases. In this study, the authors investigated the relationship between critical Hcy concentration and the risk of rupture in intracranial aneurysms (IAs). This study collected data from 423 patients with both ruptured and unruptured IAs. We compared demographic data, vascular rupture risk factors, and laboratory test results between the two groups. Multivariable logistic regression analysis was employed to determine the correlation between critical plasma Hcy levels and the risk of rupture in small to medium-sized IAs. A total of 330 cases of ruptured intracranial aneurysms (RIA) and 93 cases of unruptured intracranial aneurysms (UIA) were included. Univariate analysis revealed statistically significant differences between the ruptured and unruptured groups in terms of hypertension, hyperlipidemia, plasma Hcy levels, and IA morphology (all P < 0.05). Multivariable logistic regression analysis indicated that hypertension (odds ratio [OR] 0.504; 95% confidence interval [CI] 0.279-0.911; P = 0.023), hyperlipidemia (OR 1.924; 95% CI 1.079-3.429; P = 0.027), and plasma Hcy levels (OR 1.420; 95% CI 1.277-1.578; P < 0.001) were independently associated with the rupture of small to medium-sized IAs, all with statistical significance (P < 0.05). Our study suggests that critical plasma Hcy levels are an independent risk factor for increased rupture risk in small to medium-sized intracranial aneurysms. Therefore, reducing plasma Hcy levels may be considered a valuable strategy to mitigate the risk of intracranial vascular abnormalities rupture and improve patient prognosis.

Impact of preaneurysmal M1 length in unruptured middle cerebral artery aneurysm: mid-term outcome and single-center experience

OBJECTIVE

This study was design to investigate the surgical and functional outcome based on the preaneurysmal M1 length for unruptured MCA aneurysm.

METHODS

Among 250 consecutive patients with unruptured aneurysms operated in our institution between 2015 and 2017, 72 were MCA aneurysms. Risk factors for IR (i.e., intraoperative rupture) were investigated including age, sex, preaneurysmal M1 length, maximal MCA aneurysm diameter, neck size, aneurysm shape, sphenoid ridge proximation sign. Outcome was measured at discharge, 1 yr and last follow-up. Outcome was compared according to the preaneurysmal M1 length.

RESULTS

Among 68 patients included, five patients (7.3%) suffered IR. Mean maximal diameter of MCA aneurysm (7.9 mm ± 3.4 vs. 4.5 ± 1.8; p = 0.01) was significantly associated with IR risk. Mean M1 length seemed to be shorter in the IR group although not statistically significant (16.2 mm ± 5.1 vs. 11.5 mm ± 4.8; p = 0.053). Mid-term outcome was favorable for all patients at last follow-up but was worsen in case of short preaneurysmal M1 segment (10.7 mm ± 4.8 vs. 16.4 mm ± 5.3, p = 0.02). Complete aneurysm occlusion was achieved for sixty-nine patients (95.5%) with 6.9% of early postoperative complications.

CONCLUSIONS

The microsurgical treatment of unruptured MCA aneurysm was associated with favorable mid-term outcome in all patients and high rates of complete occlusion. Aneurysm size was significantly associated with the intraoperative rupture risk for unruptured MCA aneurysm and patients with a short preaneurysmal M1 segment seemed to have a greater risk of intraoperative rupture although not statistically significant. Short preaneurysmal M1 patients had worsen mid-term outcome.

Predictors of intraoperative intracranial aneurysm rupture in patients with subarachnoid hemorrhage: a retrospective analysis

PURPOSE

Intraoperative cerebral aneurysm rupture (IOR) is a common phenomenon with a frequency of around 19%. Research regarding IOR lacks an analysis of its predictors.

METHODS

We retrospectively examined all saccular aneurysms, in 198 patients with subarachnoid hemorrhage, surgically treated from 2013 to 2019. Operative reports, patient histories, blood test results, discharge summaries, and radiological data were reviewed. IOR was defined as any bleeding from the aneurysm during surgery, preceding putting a clip on its neck, regardless of how trivial.

RESULTS

The frequency of IOR was 20.20%. Patients with IOR had higher aneurysm dome size (9.43 ± 8.39 mm vs. 4.96 ± 2.57 mm; p < 0.01). The presence of blood clot on the aneurysm dome was significantly associated with IOR (12.50% vs. 2.53%; p < 0.01). We also associated lamina terminalis fenestration during surgery (7.50% vs. 21.52%; p = 0.04) and multiple aneurysms (5.00% vs. 18.35%; p = 0.038) with a lower risk of IOR. Glucose blood levels were also elevated in patients with IOR (7.47 ± 2.78 mmol/l vs. 6.90 ± 2.22 mmol/l; p = 0.04). Multivariate analysis associated that urea blood levels (OR 0.55, 0.33 to 0.81, p < 0.01) and multiple aneurysms (OR 0.04, 0.00 to 0.37, p = 0.014) were protective factors against the occurrence of IOR.

CONCLUSION

Large dome size of an aneurysm, a blood clot on the aneurysm dome and elevated glucose blood levels can be IOR predictive. Lamina terminalis fenestration, the appearance of multiple aneurysms, and high urea blood levels may be associated with a lower risk of such an event.

Outcomes and complications of cerebral aneurysms operated on by eyebrow incision according to aneurysm type and location

OBJECTIVE

Trans-eyebrow supraorbital aneurysmal neck clipping, also known as keyhole surgery, have many advantages of minimal invasive surgery. However, there are few studies on whether there is a difference in keyhole surgery according to the location of the aneurysm, and how the complications after keyhole approach differ from the conventional approach. The authors investigated the surgical outcome of keyhole aneurysmal surgery for clarify the characteristics of keyhole surgery.

METHODS

A retrospective study was performed with review of medical records and images of patients with anterior circulation aneurysm undergoing aneurysmal clipping with keyhole surgery. The patient's clinical condition, imaging, surgical condition, and outcome were investigated.

RESULTS

As a result of analysis about the location of the aneurysm, middle cerebral artery (MCA) aneurysm group had a longer operation time than internal carotid artery and anterior cerebral artery aneurysm groups, but there was no significant difference in complication rate. The olfactory dysfunction occurred more than that of conventional surgery and occurred less in MCA aneurysm group than others. Scalp sensory change in the surgical site was more common in patients with unruptured aneurysms.

CONCLUSION

By accurately investigating the frequency and severity of complications associated with trans-eyebrow aneurysmal neck clipping surgery, it can help to select a surgical approach considering risk versus benefit. In addition, patient's satisfaction can be increased by providing information to patients and caregivers in advance about the outcome of this approach and the anticipated complications.

Impact of aneurysm morphology on aneurysmal subarachnoid hemorrhage severity, cerebral infarction and functional outcome

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity. The objective was to evaluate, whether specific morphological aneurysm characteristics could serve as predictive values for aSAH severity, disease-related complications and clinical outcome.

METHODS

A total of 453 aSAH patients (mean age: 54.9 ± 13.8 years, mean aneurysm size: 7.5 ± 3.6 mm) treated at a single center were retrospectively included. A morphometric analysis was performed based on angiographic image sets, determining aneurysm location, aneurysm size, neck width, aneurysm size ratios, aneurysm morphology and vessel size. The following outcome measures were defined: World Federation of Neurosurgical Societies (WFNS) grade 4 and 5, Fisher grade 4, vasospasm, cerebral infarction and unfavorable functional outcome.

RESULTS

Regarding morphology parameters, aneurysm neck width was an independent predictor for Fisher 4 hemorrhage (OR: 1.1, 95%CI: 1.0-1.3, p = 0.048), while dome width (OR: 0.92, 95%CI: 0.86-0.97, p = 0.005) and internal carotid artery location (OR: 2.1, 95%CI: 1.1-4.2, p = 0.028) predicted vasospasm. None of the analyzed morphological characteristics prognosticated functional outcome. Patient age (OR: 0.95, 95%CI: 0.93-0.96, p < 0.001), WFNS score (OR: 4.8, 95%CI: 2.9-8.0, p < 0.001), Fisher score (OR: 2.3, 95%CI: 1.4-3.7, p < 0.001) and cerebral infarction (OR: 4.5, 95%CI: 2.7-7.8, p < 0.001) were independently associated with unfavorable outcome.

CONCLUSIONS

The findings indicate a correlation between aneurysm morphology, Fisher grade and vasospasm. Further studies will be required to reveal an independent association of aneurysm morphology with cerebral infarction and functional outcome.

Impact of the weekend effect on outcome after microsurgical clipping of ruptured intracranial aneurysms

BACKGROUND

The "weekend effect" describes the assumption that weekend and/or on-call duty admission of emergency patients is associated with increased morbidity and mortality rates. For aneurysmal subarachnoid hemorrhage, we investigated, whether presentation out of regular working hours and microsurgical clipping at nighttime correlates with worse patient outcome.

METHODS

This is a retrospective review of consecutive patients that underwent microsurgical clipping of an acutely ruptured aneurysm at our institution between 2010 and 2019. Patients admitted during (1) regular working hours (Monday-Friday, 08:00-17:59) and (2) on-call duty and microsurgical clipping performed during (a) daytime (Monday-Sunday, 08:00-17:59) and (b) nighttime were compared regarding the following outcome parameters: operation time, treatment-related complications, vasospasm, functional outcome, and angiographic results.

RESULTS

Among 157 enrolled patients, 104 patients (66.2%) were admitted during on-call duty and 48 operations (30.6%) were performed at nighttime. Admission out of regular hours did not affect cerebral infarction (p = 0.545), mortality (p = 0.343), functional outcome (p = 0.178), and aneurysm occlusion (p = 0.689). Microsurgical clipping at nighttime carried higher odds of unfavorable outcome at discharge (OR: 2.3, 95%CI: 1.0-5.1, p = 0.039); however, there were no significant differences regarding the remaining outcome parameters. After multivariable adjustment, clipping at nighttime did not remain as independent prognosticator of short-term outcome (OR: 2.1, 95%CI: 0.7-6.2, p = 0.169).

CONCLUSIONS

Admission out of regular working hours and clipping at nighttime were not independently associated with poor outcome. The adherence to standardized treatment protocols might mitigate the "weekend effect."

Intraoperative Aneurysm Rupture: Surgical Experience and the Rate of Intraoperative Rupture in a Series of 1000 Aneurysms Operated on by a Single Neurosurgeon

OBJECTIVE

This study aims to examine the risk factors that can cause intraoperative rupture (IOR), and especially, the role of surgical experience. To our knowledge, this is the first study to analyze the effect of the surgeon's experience on the IOR rate in 2 different perspectives.

METHODS

A total of 1000 aneurysms in 775 patients were operated on by a single neurosurgeon. The clinical and radiologic data and intraoperative video recordings of all patients were retrospectively analyzed. To evaluate the role of the surgeon's experience on the IOR rate, the aneurysms were divided chronologically into both 5-year periods and each 100 aneurysms. Number, stage, severity, location, management of IORs, and patients' outcomes were determined.

RESULTS

IOR occurred in 55 aneurysms (5.5% per aneurysm). The incidence of IOR decreased gradually in the first 2 groups of 5-year periods (11.4% and 5.9%, respectively). However, in the last 3 groups, the decline remained stable (4%-5%). Considering all groups, this decrease was statistically significant (P = 0.037). When this evaluation was made for each group of 100 aneurysms, similar results were obtained. Mortality also gradually decreased over the years (P = 0.035). Of 8 possible risk factors, rupture status was found to be the only independent predictor for IOR (OR, 8.68; 95% confidence interval, 3.69-20.47; P <0.001).

CONCLUSIONS

Increased surgical experience reduces the IOR rate from 10%-11% to 4%-5% after an average of 250 aneurysm operations. However, this rate does not decrease further with more experience. To our knowledge, a learning curve regarding IOR is presented for the first time in the literature.

Unilateral absence of the internal carotid artery associated with anterior communicating artery aneurysms: Systematic review and a proposed management algorithm

Background:

Absence or hypoplasia of the internal carotid artery (ICA) is a rare congenital anomaly that is mostly unilateral and highly associated with other intracranial vascular anomalies, of which saccular aneurysm is the most common. Blood flow to the circulation of the affected side is maintained by collateral pathways, some of which include the anterior communicating artery (Acom) as part of their anatomy. Therefore, temporary clipping during microsurgery on Acom aneurysms in patients with unilateral ICA anomalies could jeopardize these collaterals and place the patient at risk of ischemic damage. In this paper, we review the literature on cases with a unilaterally absent ICA associated with Acom aneurysms and provide an illustrative case.

Methods:

We combined our experience of one case of a unilaterally absent ICA associated with an Acom aneurysm with the 33 existing publications on the same subject in the literature, for a total of 40 cases. We provide a detailed systematic literature review of this association of vascular anomalies, exploring different aspects regarding the collateral pathways and how they impact management strategies and propose a management algorithm to deal with such association.

Results:

The mean age was 48.2 ± 16.5 years. The aneurysmal rupture was the most common presentation (75%). Agenesis was observed in 70% of patients, followed by hypoplasia (20%) and, finally, aplasia (10%). Lie Type A was the most common pattern of collaterals (50%), with Types B and D being of almost equal proportions. Most aneurysms were located at the A1-Acom junction contralateral to the anomalous side (Fisher’s Exact test; P = 0.03). One case of temporary clipping was reported in the literature.

Conclusion:

Acom aneurysms in patients with unilateral ICA anomalies, given they are more commonly present contralaterally, could be of acquired etiology, warranting periodic screening in asymptomatic patients. Temporary clipping might be safe in patients with Type D collateral pattern, while those with Types A or B may require intraoperative rupture risk assessment and a tailored management plan to avoid disrupting collateral flow and causing ischemia.

Adverse intraoperative events during surgical repair of ruptured cerebral aneurysms: a systematic review

Compared with endovascular techniques, clipping of ruptured cerebral aneurysms has been shown to associate with increased morbidity in several studies. Despite this, clipping remains the preferred option for many aneurysms. The objective of this study is to describe the reported adverse events of open repair of ruptured cerebral aneurysms and their impact on patient outcome. The PubMed, Embase and Cochrane databases were searched between June 1999 and June 2019 to identify original studies of at least 100 patients undergoing surgical repair of ruptured cerebral aneurysms and in which adverse event rates were reported. Thirty-six studies reporting adverse events in a total of 12,410 operations for repair of ruptured cerebral aneurysms were included. Surgical adverse events were common with 36 event types reported including intraoperative rupture (median rate of 16.6%), arterial injury (median rate of 3.8%) and brain swelling (median rate 5.6%). Only 6 surgical events were statistically shown to associate with poor outcomes by any author and for intraoperative rupture (the most frequently analysed), there was an even split between authors finding a statistical association with poor outcome and those finding no association. Even with modern surgical techniques, the technical demands of surgical aneurysm repair continue to lead to a high rate of intraoperative adverse events. Despite this, it is not known which of these intraoperative events are the most important contributors to the poor outcomes often seen in these patients. More research directed towards identifying the events that most drive operative morbidity has the potential to improve outcomes for these patients.

Impact of aneurysm shape and neck configuration on cerebral infarction during microsurgical clipping of intracranial aneurysms

OBJECTIVE

Cerebral infarction is a significant cause of morbidity and mortality related to microsurgical clipping of intracranial aneurysms. The objective of this study was to determine the impact of aneurysm shape and neck configuration on cerebral infarction after aneurysm surgery.

METHODS

The authors retrospectively reviewed consecutive cases of ruptured and unruptured aneurysms treated with microsurgical clipping at their institution between 2010 and 2018. Three-dimensional reconstructions from preoperative computed tomography and digital subtraction angiography were used to determine aneurysm shape (regular/complex) and neck configuration (regular/irregular). Morphological and procedure-related risk factors for cerebral infarction were identified using univariate and multivariate statistical analyses.

RESULTS

Among 243 patients with 252 aneurysms (148 ruptured, 104 unruptured), the overall cerebral infarction rate was 17.1%. Infarction tended to occur more often in aneurysms with complex shape (p = 0.084). Likewise, aneurysms with an irregular neck had a significantly higher rate of infarction (37.5%) than aneurysms with regular neck configuration (10.1%, p < 0.001). Aneurysms with an irregular neck were associated with a higher rate of intraoperative rupture (p = 0.003) and temporary parent artery occlusion (p = 0.037). In the multivariate analysis, irregular neck configuration was identified as an independent risk factor for infarction (OR 4.2, 95% CI 1.9-9.4, p < 0.001), whereas the association between aneurysm shape and infarction was not significant (p = 0.966).

CONCLUSIONS

Irregular aneurysm neck configuration represents an independent risk factor for cerebral infarction during microsurgical clipping of both ruptured and unruptured aneurysms.

Penumbral Salvage by Delayed Clip Reposition 19 Hours After Cerebral Aneurysm Clipping-Induced Ischemia Results in Neurologic Restitution-Correlation with Indocyanine Green Videoangiography and FLOW 800 Measurements

BACKGROUND

Cerebral infarction because of parent artery stenosis represents a potential complication of microsurgical aneurysm clipping.

CASE DESCRIPTION

We report a case of a 60-year-old woman that developed left-sided hemiparesis and aphasia 9 hours after clipping of an unruptured middle cerebral artery aneurysm with heavy calcification of the aneurysm neck. Angiographic workup revealed a marked parent artery stenosis, which occurred presumably because of thrombus generation at the reconstructed aneurysm neck. Revision surgery with relocation of the aneurysm clip was ultimately performed 19 hours after symptom onset. Although follow-up computed tomography scan showed a small cerebral infarction, the patient recovered fully from surgery.

CONCLUSIONS

This case shows that relocation of the aneurysm clip in case of vessel stenosis can lead to penumbral salvage, even when performed more than 6 hours after symptom onset.

Clip Compression Injury of the Oculomotor Nerve: Its Prevention and Recovery

Clip compression injury of oculomotor nerve (ON) is a preventable complication of aneurysm microsurgery. The author illustrates this condition in which ON was inadvertently occluded by the clip during repairing posterior communicating artery (PcoA) aneurysm. The report indicates that the surgeon should be meticulous in identifying and protecting ON at clipping stage when PcoA aneurysm prematurely bursts.

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

OBJECTIVE

Although the risk of aneurysm remnants after microsurgical clipping is generally low, complete aneurysm occlusion is not always guaranteed. We performed a morphometric analysis of intracranial aneurysms to identify predictors for aneurysm remnants and to propose a novel risk score.

METHODS

This is a retrospective, single-center analysis of consecutive patients with ruptured and unruptured aneurysms who underwent microsurgical clipping and postoperative digital subtraction angiography between 2010 and 2018. Based on preoperative rotational angiography, distinct morphologic aneurysm characteristics were determined and correlated with postoperative angiographic results. Factors predictive in the univariate and multivariate analyses were determined to establish a risk score for postoperative remnants after aneurysm clipping.

RESULTS

Among 140 patients with 166 clipped aneurysms, aneurysm remnants were present in 19.9%. In the multivariate analysis, ruptured aneurysm status (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.7-36; P < 0.01) and increased aspect ratio (OR, 1.9; 95% CI, 1.0-4.0; P = 0.07) were associated with postoperative aneurysm remnants. Anterior communicating artery location (P = 0.02), internal carotid artery location (P = 0.06), increased aneurysm inclination angle (P < 0.01), and irregular aneurysm shape (P = 0.07) were further predictors for aneurysm remnants in the univariate analysis. These factors were weighted and included into a risk sum score for postoperative aneurysm remnants (range, 0-8 points), which performed with good accuracy (area under the curve = 0.807).

CONCLUSIONS

After external validation of the proposed risk score, it could help identify cases requiring angiographic control after aneurysm surgery.

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.

Impact of aneurysm shape on morbidity after clipping of unruptured intracranial aneurysms

BACKGROUND

Complex aneurysm shape is a predominant risk factor for aneurysm rupture but its impact on clinical outcome after clipping remains unclear. The objective of the present study was to compare complications and morbidity after clipping of unruptured single-sac aneurysms (SSAs) and aneurysms with multiple sacs (MSAs).

METHODS

A retrospective, single-center study was conducted for patients that were treated between 2010 and 2018. We analyzed surgical parameters, treatment-related complications, and morbidity, defined as any increase in the modified Rankin scale at 3-month follow-up.

RESULTS

We identified 101 patients (mean age: 52.9 ± 10.5 years) that underwent clipping for 57 SSAs and 44 MSAs. The two groups were comparable regarding aneurysm size and neck width. Clipping of MSAs was associated with a longer operation time (p = 0.008) and increased use of intraoperative indocyanine green (p = 0.016) than SSAs. Complications occurred more often in the MSA group (29.5%) than in the SSA group (14.0%; p = 0.057). Morbidity was significantly higher in the MSA group (20.5%) than in the SSA group (3.5%, p = 0.009). In the univariate analysis, the odds of morbidity were 7.1 times greater for MSAs than for SSAs (95% CI 1.4-34.7).

CONCLUSIONS

Morbidity after microsurgical clipping is significantly increased in MSAs as compared to SSAs. This may be attributed to a more difficult clip placement with stronger manipulation of the aneurysm dome and the surrounding brain tissue.