Analysis of intraoperative rupture in the surgical treatment of 1694 saccular aneurysms

In Vivo Deformation of the Human Basilar Artery

An estimated 6.8 million people in the United States have an unruptured intracranial aneurysms, with approximately 30,000 people suffering from intracranial aneurysms rupture each year. Despite the development of population-based scores to evaluate the risk of rupture, retrospective analyses have suggested the limited usage of these scores in guiding clinical decision-making. With recent advancements in imaging technologies, artery wall motion has emerged as a promising biomarker for the general study of neurovascular mechanics and in assessing the risk of intracranial aneurysms. However, measuring arterial wall deformations in vivo itself poses several challenges, including how to image local wall motion and deriving the anisotropic wall strains over the cardiac cycle. To overcome these difficulties, we first developed a novel in vivo MRI-based imaging method to acquire cardiac gated images of the human basilar artery (BA) over the cardiac cycle. Next, complete BA endoluminal surfaces from each frame were segmented, producing high-resolution point clouds of the endoluminal surfaces. From these point clouds we developed a novel B-spline-based surface representation, then exploited the local support nature of B-splines to determine the local endoluminal surface strains. Results indicated distinct regional and temporal variations in BA wall deformation, highlighting the heterogeneous nature BA function. These included large circumferential strains (up to ∼ 20 % ), and small longitudinal strains, which were often contractile and out of phase with the circumferential strains patterns. Of particular interest was the temporal phase lag in the maximum circumferential perimeter length, which indicated that the BA deforms asynchronously over the cardiac cycle. In summary, the proposed method enabled local deformation analysis, allowing for the successful reproduction of local features of the BA, such as regional principal stretches, areal changes, and pulsatile motion. Integrating the proposed method into existing population-based scores has the potential to improve our understanding of mechanical properties of human BA and enhance clinical decision-making.

Partial coil embolization before surgical clipping of ruptured intracranial aneurysms

OBJECTIVE

Intraoperative rupture (IOR) is the most common adverse event encountered during surgical clip obliteration of ruptured intracranial aneurysms. Besides increasing surgeon experience and early proximal control, no methods exist to decrease IOR risk. Thus, our objective was to assess if partial endovascular coil embolization to protect the aneurysm before clipping decreases IOR.

METHODS

We conducted a retrospective analysis of patients with ruptured intracranial aneurysms that were treated with surgical clipping at two tertiary academic centers. We compared patient characteristics and outcomes of those who underwent partial endovascular coil embolization to protect the aneurysm before clipping to those who did not. The primary outcome was IOR. Secondary outcomes were inpatient mortality and discharge destination.

RESULTS

We analyzed 100 patients. Partial endovascular aneurysm protection was performed in 27 patients. Age, sex, subarachnoid hemorrhage severity, and aneurysm location were similar between the partially-embolized and non-embolized groups. The median size of the partially-embolized aneurysms was larger (7.0 mm [interquartile range 5.95-8.7] vs. 4.6 mm [3.3-6.0]; P < 0.001). During surgical clipping, IOR occurred less frequently in the partially-embolized aneurysms than non-embolized aneurysms (2/27, 7.4%, vs. 30/73, 41%; P = 0.001). Inpatient mortality was 14.8% (4/27) in patients with partially-embolized aneurysms and 28.8% (21/73) in patients without embolization (P = 0.20). Discharge to home or inpatient rehabilitation was 74.0% in patients with partially-embolized aneurysms and 56.2% in patients without embolization (P = 0.11). A complication from partial embolization occurred in 2/27 (7.4%) patients.

CONCLUSIONS

Preoperative partial endovascular coil embolization of ruptured aneurysms is associated with a reduced frequency of IOR during definitive treatment with surgical clip obliteration. These results and the impact of preoperative partial endovascular coil embolization on functional outcomes should be confirmed with a randomized trial.

The anterior communicating artery variants: a meta-analysis with a proposed classification system

Morphological and morphometric variants of the anterior communicating artery (AComA) have been described by multiple studies; however, a complete classification system of all possible morphological variants with their prevalence is lacking. The current systematic review with meta-analysis combines data from different databases, concerning the AComA morphological and morphometric variants (length and diameter). Emphasis was given to the related clinical implications to highlight the clinical value of their knowledge. The typical AComA morphology occurs with a pooled prevalence (PP) of 67.3%, while the PP of atypical AComA is 32.7%. The identified AComA morphological variants (artery's hypoplasia, absence, duplication, triplication, differed shape, fenestration, and the persistence of a median artery of the corpus callosum- MACC) were classified in order of frequency. The commonest presented variants were the AComA hypoplasia (8%) and the anterior cerebral artery (ACA) fusion (5.9%), and the rarest ones were the MACC persistence (2.3%), and the AComA triplication (0.7%). The knowledge of those variants is essential, especially for neurosurgeons operating in the area. Given the high prevalence of AComA aneurysms, an adequate and complete classification of those variants is of utmost importance.

Role of temporary arterial occlusion in subarachnoid hemorrhage outcomes: a prospective cohort study

PURPOSE

Temporary arterial occlusion (TAO) is a widespread practice in the surgical treatment of intracranial aneurysms. This study aimed to investigate TAO's role during ruptured aneurysm clipping as an independent prognostic factor on short- and long-term outcomes.

METHODS

This prospective cohort included 180 patients with ruptured intracranial aneurysms and an indication of microsurgical treatment. Patients who died in the first 12 hours after admission were excluded.

RESULTS

TAO was associated with intraoperative rupture (IOR) (odds ratio - OR = 10.54; 95% confidence interval - 95%CI 4.72-23.55; p < 0.001) and surgical complications (OR = 2.14; 95%CI 1.11-4.07; p = 0.01). The group with TAO and IOR had no significant difference in clinical (p = 0.06) and surgical (p = 0.94) complications compared to the group that had TAO, but no IOR. Among the 111 patients followed six months after treatment, IOR, number of occlusions, and total time of occlusion were not associated with Glasgow Outcome Scale (GOS) in the follow-up (respectively, p = 0.18, p = 0.30, and p = 0.73). Among patients who underwent TAO, IOR was also not associated with GOS in the follow-up (p = 0.29).

CONCLUSIONS

TAO was associated with IOR and surgical complications, being the latter independent of IOR occurrence. In long-term analysis, neither TAO nor IOR were associated with poor clinical outcomes.

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.

Prognostic Risk Factors of One-stage Surgical Clipping in aSAH Elderly Patients with MIAs

OBJECTIVE

To discuss the prognostic factors affecting the prognosis of 1-stage surgical clipping in aneurysmal subarachnoid hemorrhage (aSAH) elderly patients with multiple intracranial aneurysms (MIAs).

MATERIALS AND METHODS

A total of 84 elderly patients with aSAH who had MIAs and underwent 1-stage surgical clipping were retrospectively analyzed. Follow-up was conducted with patients 30 days after discharge using the Glasgow Outcome Scale (GOS). A GOS score of 1 to 3 was defined as a poor outcome, and a GOS score of 4 to 5 was defined as a good outcome. General information (gender, age, size of aneurysm, location of rupture of the responsible aneurysm, H-H grade, CT characteristics of aSAH, number of subarachnoid hemorrhages, operation opportunity, postoperative complications, and intraoperative rupture) and complications（cerebral infarction, hydrocephalus, electrolyte disturbance, and encephaledema）were recorded. Univariate analysis and multivariate regression analysis were used to analyze factors that may affect outcomes.

RESULTS

Univariate analysis showed that the number of SAH events ( P =0.005), intraoperative rupture ( P =0.048) and postoperative complications ( P =0.002) were associated with the prognosis of aSAH elderly patients with MIAs undergoing 1-stage surgery. Multivariate analysis showed that the number of SAH events (odds ratio [OR] 4.740, 95% confidence interval [CI] 1.056 to 21.282, P =0.042) and postoperative complications (OR 4.531, 95% CI 1.266 to 16.220, P =0.020) were independently associated with the prognosis of aSAH elderly patients with MIAs undergoing 1-stage surgery.

CONCLUSIONS

The number of SAH events and postoperative complications are independent risk factors for the prognosis of aSAH elderly patients with MIAs undergoing 1-stage surgery. These factors contribute to the timely treatment of potentially related patients.

Adverse events associated with microsurgial treatment for ruptured intracerebral aneurysms: a prospective nationwide study on subarachnoid haemorrhage in Sweden

BACKGROUND

Adverse events (AEs) or complications may arise secondary to the treatment of aneurysmal subarachnoid haemorrhage (SAH). The aim of this study was to identify AEs associated with microsurgical occlusion of ruptured aneurysms, as well as to analyse their risk factors and impact on functional outcome.

METHODS

Patients with aneurysmal SAH admitted to the neurosurgical centres in Sweden were prospectively registered during a 3.5-year period (2014-2018). AEs were categorised as intraoperative or postoperative. A range of variables from patient history and SAH characteristics were explored as potential risk factors for an AE. Functional outcome was assessed approximately 1 year after the bleeding using the extended Glasgow Outcome Scale.

RESULTS

In total, 1037 patients were treated for ruptured aneurysms, of which, 322 patients were treated with microsurgery. There were 105 surgical AEs in 97 patients (30%); 94 were intraoperative AEs in 79 patients (25%). Aneurysm rerupture occurred in 43 patients (13%), temporary occlusion of the parent artery >5 min in 26 patients (8%) and adjacent vessel injury in 25 patients (8%). High Fisher grade and brain oedema on CT were related to increased risk of AEs. At follow-up, 38% of patients had unfavourable outcome. Patients suffering AEs were more likely to have unfavourable outcome (OR 2.3, 95% CI 1.10 to 4.69).

CONCLUSION

Intraoperative AEs occurred in 25% of patients treated with microsurgery for ruptured intracerebral aneurysm in this nationwide survey. Although most operated patients had favourable outcome, AEs were associated with increased risk of unfavourable outcome.

Robotic Arm-Protected Microsurgical Pericallosal and Middle Cerebral Artery Aneurysm Clipping: A Technical Note and Case Series

BACKGROUND

Managing intraoperative aneurysm rupture (IAR) during intracranial aneurysm clipping can be challenging given the excessive hemorrhage and limited field of view under the microscope for visualizing the proximal artery and safe temporary clipping.

OBJECTIVE

To describe the first known use of robotic arm for safeguarding IAR in microsurgical aneurysm clipping.

METHODS

A robotic arm was used to safeguard 3 microsurgical clipping cases (1 pericallosal and 2 middle cerebral artery) performed by a single surgeon. The device was installed onto the side rail of the operating table along with the clip applier attachment. After dissecting the cerebral artery segment proximal to the aneurysm, a temporary aneurysm clip was loaded and established at the appropriate segment before dissecting distally toward the aneurysm.

RESULTS

Setup for the robotic arm and temporary clip was simple, quick, precise, and without any unforeseen accommodations needed in all 3 instances. The temporary clip acted as an emergency gate and could be deployed either manually or remotely through a controller. IAR occurred in case 1, and the robotic-assisted temporary clip deployment achieved immediate hemostasis without complications. This method bypassed the need for significant suctioning, packing, and further exploration for safe temporary clipping. Case 2 and 3 demonstrated the feasibility for middle cerebral artery protection and ease of intraoperative readjustment.

CONCLUSION

This technical note highlights the feasibility and relative ease of using a robotic arm as a safeguard device, and it enables on-demand control of proximal blood flow and may enhance the safety of microsurgical aneurysm procedures.

Management of Intraoperative Rupture of Intracranial Aneurysms: Agony and Ecstasy

Intraoperative rupture (IOR) of an intracranial aneurysm is a serious complication, often with catastrophic consequences that are difficult to manage even by the best hands. Like most surgical complications, this one is better to avoid than to treat, but any vascular neurosurgeon should know how to deal with IOR of an aneurysm, because it is bound to occur. The aims of this study were to evaluate the incidence and factors associated with IOR during clipping of intracranial aneurysms, to analyze strategies for controlling hemorrhage in such cases, and to assess outcomes. Overall, 911 cases of intracranial aneurysms, which were treated surgically by the author during 26 years of his professional career, were reviewed. IOR was never noted during clipping of an unruptured intracranial aneurysm (65 cases) but was encountered in 49 of 846 cases (5.8%) presenting with subarachnoid hemorrhage. This complication occurred most often in cases of internal carotid artery aneurysms (22 cases; 45%), followed by anterior communicating artery aneurysms (12 cases; 24%), distal anterior cerebral artery aneurysms (6 cases; 12%), middle cerebral artery aneurysms (6 cases; 12%), and posterior circulation aneurysms (3 cases; 6%). IOR was mostly encountered during early surgery (within 3 days) after the ictus (26 cases; 53%) and most frequently occurred during dissection of the aneurysm (26 cases; 53%). Overall, 22 patients (45%) had good outcome, 18 (37%) had variable morbidity, and 9 (18%) died. Fatal consequences of IOR were noted only in cases of big or multilobulated internal carotid artery aneurysms. Detailed planning of the surgical procedure, application of meticulous microdissection techniques, and anticipation of possible intraoperative incidents during intervention aimed at clipping of an intracranial aneurysm can reduce the risk of IOR, as well as the associated morbidity and mortality.

Complications of Endovascular and Open Aneurysm Surgery in the Era of Flow Diversion

The techniques used for treatment of intracranial aneurysms have progressed dramatically over the decades. The introduction of modern endovascular techniques and the continued refinement of progressively less invasive neurosurgical approaches have contributed to steadily improving clinical outcomes. Moreover, innovations such as flow-diverting stents have achieved dramatic success and have gained rapid widespread adoption. Particularly in lesions for which the application of conventional treatment techniques is difficult, flow diversion technology has revolutionized aneurysm management. This review provides a discussion on the morbidity and mortality encountered in the treatment of intracranial aneurysms in the modern era. Common adverse events faced in the management of these lesions with open surgery and various endovascular techniques are highlighted.

Treatment of a ruptured fetal-type posterior communicating aneurysm with a combined approach using the new contour neurovascular system

Fetal-type posterior communicating artery (FPCom) aneurysms are associated with higher rates of recurrence after endovascular treatment than aneurysms at other locations. We report the case of a patient with a subarachnoid haemorrhage and ruptured right-sided FPCom aneurysm. The patient underwent acute endovascular treatment with application of a novel combined approach-partial coiling to protect the dome and occlusion of the neck with a new flow-disrupter, endosaccular device, Contour (Cerus Endovascular)-as a stable, single-step treatment to prevent rebleeding in the acute stage and long-term potential recurrences.

Risk factors and outcome analysis of patients with intraoperative rupture (IOR) of ruptured cerebral aneurysm during microsurgical clipping

PURPOSE

To analyse baseline characteristics of patients with intraoperative rupture (IOR) or non-IOR who underwent microsurgical clipping for ruptured intracranial aneurysms. Additionally, to asses functional outcome in terms of Glasgow Outcome Scale (GOS) at 6 and 12 months.

METHODS

A retrospective analysis of 471 patients who underwent microsurgical clipping for ruptured intracranial aneurysms from 2007 to 2018 in Nepal Mediciti Hospital, Nepal. Patients who underwent surgery for unruptured aneurysm were excluded from the study. The association of the base line characteristic in IOR and non-IOR were analysed. Variables analysed were the Hunt and Hess Scale (HHS) dichotomized as (1-3) and (4-5), Modified Fisher Scale dichotomized as (0-2) and (3-4), type of rupture, use of brain retractor, timing of IOR during surgery, aneurysmal factors (size of the neck, location, lobulation) and time of surgery. Outcome, GOS dichotomized into favourable (4-5) and unfavourable (1-3), assessed at 6 months and 12 months.

RESULTS

Out of 471 patients treated for ruptured intracranial aneurysm, IOR occurred in 57 (12.10%) with mean age 49.47 (SD ±12.9), occurred more in smoker than non-smoker (45.6% vs. 18.6%; p=.000) and regular alcohol consumers (36.8% vs. 17.9%; p=.004). Favourable outcome with GOS (4-5) at 6 months was observed among patients with lower HHS (1-3), p=.025 and lower MFS (0-2), p=.04. However, outcome at 12 months was better associated with MFS (p=.013) and aneurysm size (p=.038), with more favourable outcome associated with aneurysm less than 10 mm.

CONCLUSIONS

Alcohol consumption and smoking are associated risk factors that may contribute to IOR. HHS and MFS are strong predictors of outcome for IOR patients at 6 months. However, at 12 months, MFS is more predictive of outcome. Aneurysms greater than 10 mm had a strong association with outcome at 12 months than 6 months.

An MRI study of typical anatomical variants of the anterior communicating artery complex

PURPOSE

This magnetic resonance imaging study examined the most frequent anatomical variants of the anterior communicating artery (ACoA) complex of the cerebral arterial circle, and aimed to determine whether they were associated with ACoA complex aneurysm.

METHODS

The study enrolled 669 patients. Using three-dimensional time-of-flight magnetic resonance angiography, 617 patients were classified into the following groups based on the anatomical variation in the ACoA complex: no ACoA complex anomaly; ACoA complex aneurysm; and vascular anomaly distant from the cerebral arterial circle.

RESULTS

Of the 617 classified subjects, the classical anatomical description applied to 48.73% in the no ACoA complex anomaly group and 37.5% in the ACoA complex aneurysm group. One variant (left anterior cerebral artery segment A1 hypoplasia) was significantly more frequent in the ACoA complex aneurysm group. There was no sex difference in the prevalence of any variant.

CONCLUSIONS

Anatomical variants of the ACoA complex of the cerebral arterial circle were found in almost half of the subjects. One variant seemed to be associated with a higher likelihood of an aneurysm, but causality could not be inferred.

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.

Prediction of the difficulty of proximal vascular control using 3D-CTA for the surgical clipping of internal carotid artery-posterior communicating artery aneurysms

OBJECTIVE

During surgical clipping of internal carotid artery (ICA)-posterior communicating artery (PCoA) aneurysms, proximal vascular control (PVC) is difficult to achieve in some cases because of variations in the anatomy of this type of aneurysm and its parent arteries. The authors investigated morphometric features that may be predictive for the necessity of anterior clinoidectomy (ACL) or cervical ICA exposure for PVC.

METHODS

The authors retrospectively reviewed 65 patients with an ICA-PCoA aneurysm treated with clipping during the previous 3 years. The factors considered for assessing the difficulty of attaining PVC included the following: the maximum diameter of the aneurysm; the distance between the tip of the anterior clinoid process (ACP) and the proximal aneurysmal neck; the presence of calcification at the ophthalmic segment of the ICA; and the angles between the communicating segment of the ICA and the ophthalmic segment of the ICA and a line perpendicular to the cranial base, which reflect the tortuosity of the ICA. These parameters were measured based on preoperative CTA results.

RESULTS

In a total of 21 patients (32.3%), PVC was difficult to perform with the usual pterional approach. In 6 patients, temporary artery occlusions (TAOs) were difficult to achieve because of severe atherosclerotic wall changes in the ophthalmic segment of the ICA. For 15 patients, the ACPs overhanging the ophthalmic segment of the ICA obstructed the ability to secure a space for TAO. In the 21 patients with PVC difficulty, ACL alone, cervical ICA exposure alone, and both ACL and cervical ICA exposure were conducted in 6, 8, and 7 patients, respectively. Multivariate analysis with binary logistic regression revealed that the maximum diameter of the aneurysm (p = 0.041), the distance between the proximal neck of the aneurysm and the ACP tip (p = 0.002), and calcification of the ICA ophthalmic segment (p = 0.001) were significant predictive factors for difficulties with PVC. A receiver operating characteristic curve analysis revealed that a distance between the proximal aneurysmal neck and the ACP tip of ≤ 5.4 mm was the best cutoff value for predicting the difficulty of attaining PVC (area under the curve 0.800, sensitivity 80.0%, specificity 80.0%).

CONCLUSIONS

A short distance between the proximal aneurysmal neck and the ACP tip and the presence of calcification at the ophthalmic segment of the ICA on preoperative CTA are helpful for predicting the difficulty of achieving PVC.

Surgical Treatment of Middle Cerebral Artery Aneurysms: Hints and Precautions for Young Cerebrovascular Surgeons

BACKGROUND AND OBJECTIVE

 Clipping is still considered the treatment of choice for middle cerebral artery (MCA) aneurysms due to their angioarchitectural characteristics as they are often bifurcation dysplasias, needing a complex reconstruction rather than a simple exclusion. Thus, maintaining this surgical expertise is of paramount importance to train of young cerebrovascular surgeons. To balance for the increasingly limited experience due the worldwide general inclination toward the endovascular approaches, it is important to provide to the young neurosurgeons rules and operative nuances to guide this complex surgery. We describe the technical algorithm we use to teach our residents to approach ruptured and unruptured MCA aneurysms, which may help to develop a procedural memory useful to perform an effective and safe surgery.

MATERIALS AND METHODS

 We reviewed our last 10 years' institutional experience of about 400 cases of ruptured and unruptured MCA aneurysms clipping, analyzing our technical refinements and the difficulties in residents and young neurosurgeons teaching, to establish fundamental key-points and design a didactic algorithm that includes operative instructions and safety rules.

RESULTS

 We recognized seven pragmatic technical key points regarding craniotomy, sylvian fissure opening, basal cisternostomy, proximal vessel control, lenticulostriate arteries preservation, aneurysm neck microdissection, and clipping to use as a didactic algorithm for teaching residents, and as operative instructions for inexperienced neurosurgeons.

CONCLUSION

 In the setting of clipping MCA aneurysms, respect for surgical rules is of paramount importance to perform an effective and safe procedure, ensure the best aneurysm exclusion, and preserve the flow in collaterals and perforators.

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.

Predictors of Intraoperative Aneurysm Rupture, Aneurysm Remnant, and Brain Ischemia following Microsurgical Clipping of Intracranial Aneurysms: Single-Center, Retrospective Cohort Study

BACKGROUND AND STUDY AIMS

 Complete microsurgical clip occlusion of an aneurysm is one of the most important challenges in cerebrovascular surgery. Incorrect position of clip blades as well as intraoperative aneurysm rupture can expose the patient to serious complications such as rebleeding in case of aneurysm remnant and cerebral ischemia in case of occlusion of branching arteries or perforators. The aim of this study was to identify independent predictors of surgery-derived complications (aneurysm remnant and brain ischemia) as well as intraoperative aneurysm rupture in an institutional series of patients.

MATERIAL AND METHODS

 This is a single-institution, retrospective cohort study including 147 patients with 162 aneurysms that were selected for microsurgical clipping due to intracranial aneurysm in a 5-year period. Bivariate and multivariate analyses were performed to identify independent predictors among demographic, clinical, and radiographic factors.

RESULTS

 Increasing aneurysm size with a cutoff value at 9 mm (p = 0.009; odds ratio [OR]: 0.644) and irregular dome shape (p = 0.003; OR: 4.242) were independently associated with brain ischemia and aneurysm remnants that occurred in 13.6 and 17.3% of patients in our group, respectively. Intraoperative rupture was encountered in 27% of patients and its predictors were patient's age (p = 0.002; OR: 1.073) and increasing aneurysm size with a cutoff value at 7 mm (p = 0.003; OR: 1.205).

CONCLUSION

 Aneurysm size, patient's age, and irregular dome shape were the most important risk factors of aneurysm remnant, brain ischemia, and intraoperative aneurysm rupture in our series of patients. We were not able to define a cutoff value for patient's age, but our results showed that with increasing age the risk of intraoperative aneurysm rupture increased.

Impact of perioperative aneurysm rebleeding after subarachnoid hemorrhage

OBJECTIVE

Aneurysm rebleeding is a major cause of death and morbidity in patients with aneurysmal subarachnoid hemorrhage (SAH). Recognizing the predictors of rebleeding might help to identify patients who will benefit from acute management. This study was performed to investigate the predictors of aneurysm rebleeding and their impact on clinical outcomes in the preoperative, intraoperative, and postoperative periods.

METHODS

The incidence of rebleeding, demographic data, and clinical data from 4933 patients with aneurysmal SAH beginning in the year 2000 were retrospectively analyzed in the Nagasaki SAH Registry Study. The authors performed multiple logistic regression analyses to identify the risk factors contributing to rebleeding and outcome after SAH.

RESULTS

Preoperative rebleeding occurred in 7.2% of patients. Patient age (p = 0.01), multiple aneurysms (p < 0.01), aneurysm size (p < 0.0001), and heart disease (p = 0.03) were significantly associated with preoperative rebleeding. Conversely, intraoperative rebleeding occurred in 11.2% of patients. Aneurysm location (anterior communicating artery [ACoA]), family history (p = 0.02), preoperative rebleeding (p < 0.01), and clipping/coiling (p < 0.0001) were significantly associated with intraoperative rebleeding. Interaction analysis showed that clipping significantly affected intraoperative rebleeding at the ACoA (OR 4.00; 95% CI 1.82-8.80; p < 0.001). Postoperative rebleeding occurred in 2.4% of patients. Coiling/clipping (p < 0.0001) and intraoperative rebleeding (p < 0.01) were significantly associated with postoperative rebleeding. Rebleeding in all time periods examined significantly contributed to the clinical outcome after SAH.

CONCLUSIONS

Aneurysm rebleeding after SAH has specific characteristics in the preoperative, intraoperative, and postoperative periods, and all of these characteristics contribute to the clinical outcome. The ACoA has a higher risk of intraoperative rebleeding, and endovascular coiling could be a good candidate in terms of techniques for preventing intraoperative rebleeding, although complete aneurysm obliteration should be accomplished.

Adenosine-induced transient asystole to control intraoperative rupture of intracranial aneurysms: institutional experience and systematic review of the literature

BACKGROUND

Intraoperative rupture of an intracranial aneurysm is a life-threatening situation that carries a high risk of morbidity and mortality. Since 2000, adenosine has been used successfully to induce transient hypotension and/or asystole to control bleeding and facilitate surgical clipping of aneurysms that rupture intraoperatively. Given the paucity of reports describing this method in a limited number of patients, we performed a systematic review of the literature detailing the use and outcomes of this technique.

METHODS

The authors performed a systematic review and identified all studies in which adenosine was used in the setting of an intracranial aneurysm that ruptured intraoperatively. We then determined overall morbidity and mortality rates, adding an additional six of our own patients.

RESULTS

Data was analyzed for a total of 29 patients, including 23 previously reported patients from the literature and 6 additional cases from our own experience (mean age 54.8 years, 58.6% female). Most patients (82.8%, 24/29) presented with subarachnoid hemorrhage (SAH). Overall mean dose of adenosine was 51.8 mg. Successful clipping was achieved in 100% of patients. Transient or permanent morbidity was reported in 5/29 (17.2%) and the overall mortality rate was 31% (9/29), which occurred primarily due to an initial severe SAH and its resultant complications.

CONCLUSIONS

Adenosine-induced circulatory arrest appears to safely control intraoperative bleeding and facilitate the clipping of ruptured intracranial aneurysms based on the limited published literature available. Further studies comparing patient outcomes using this technique to traditional approaches are required to validate the safety and efficacy of adenosine in this high-risk setting.

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.

Cerebral Aneurysms in Autosomal Dominant Polycystic Kidney Disease: A Comparison of Management Approaches

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is a risk factor for formation of intracranial aneurysms (IAs), though the ideal screening and treatment strategies in this population are unclear.

OBJECTIVE

To report outcomes of observation, open surgical, or endovascular management of ruptured and unruptured aneurysms in patients with ADPKD.

METHODS

We performed a retrospective analysis of all patients with ADPKD and IAs at a single center from 2000 to 2016.

RESULTS

Forty-five patients with ADPKD harboring 71 aneurysms were identified, including 11 patients with subarachnoid hemorrhage (SAH). Of 22 aneurysms managed with observation, none ruptured in 136 yr of clinical follow-up. Thirty-five aneurysms were treated with open surgery and 14 with an endovascular approach. Among treated aneurysms, poor neurologic outcome (modified Rankin scale >2) was seen only in patients presenting with SAH (17% SAH vs 0% elective, P = .06). Acute kidney injury (AKI) was also significantly associated with SAH presentation (22% SAH vs 0% elective, P = .05). Neither procedural complications nor AKI were associated with treatment modality. Among 175 yr of radiographic follow-up in patients with known IAs, 8 de novo aneurysms were found, including 3 that were treated. Of 11 patients with SAH, 7 ruptured in the setting of previously known ADPKD, including 2 with prior angiographic screening and 5 without screening.

CONCLUSION

Poor outcomes occurred only with ruptured presentation but were equivalent between treatment modalities. Screening is performed only selectively, and 64% (7 of 11) of patients presenting with SAH had previously known ADPKD.

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.

Surgical Treatment of Ruptured Anterior Circulation Aneurysms: Comparative Analysis of Modified Mini-Pterional and Standard Pterional Craniotomies

Background

Minimally invasive surgical techniques for cerebral aneurysms have been developed.

Aims

To compare the efficacy and safety of modified mini-pterional (mMPT) and standard pterional (PT) craniotomies for ruptured anterior circulation aneurysms.

Materials and Methods

A total of 45 patients with ruptured anterior circulation aneurysms underwent surgical clipping; for 21 patients PT was used and for 24 patients mMPT was used. Initial clinical demographics and outcomes were retrospectively compared. A systemic inflammatory response syndrome (SIRS) score was derived by summing the number of variables meeting standard criteria for SIRS.

Results

The two groups were comparable with initial clinical demographics. Total operative time was significantly shorter in the mMPT (166.6 minutes, P = 0.001) compared with the PT (235 minutes). The rate of permanent operative morbidity were similar in both groups (P = 0.92). The mean SIRS score at 24 hours after the completion of the operation was significantly lower for patients in the mMPT group (0.96, P = 0.01) as compared to the patients in the PT group (1.81). The rate of postoperative symptomatic vasospasm was significantly lower in patients operated through the mMPT (8.3%, P = 0.03) than the PT (38.1%). Good outcome at discharge was more frequently seen in the mMPT (91.7%) than in the PT (70%), but this difference was not statistically significant (P = 0.11).

Conclusion

The mMPT craniotomy is a safe and less invasive approach for ruptured anterior circulation aneurysms, leading to a significant lower rate of postoperative symptomatic vasospasm and a marginally significant improvement in clinical outcomes.

Clinical and morphological profile of aneurysms of the anterior communicating artery treated at a neurosurgical service in Southern Brazil

Background:

The aim of the study was to characterize the clinical profile of patients with anterior communicating artery (ACoA) aneurysms and examine potential correlations between clinical findings, aneurysm morphology, and outcome.

Methods:

A review of medical records and diagnostic neuroimaging reports of patients treated at a neurosurgical service in Porto Alegre, Brazil, between August 2008 and January 2015 was performed.

Results:

During the period, 100 patients underwent surgery for ACoA aneurysms. Fifteen had unruptured aneurysms and 85 had ruptured aneurysms. Ruptured aneurysms had a higher aspect ratio than unruptured ones (2.37 ± 0.71 vs. 1.93 ± 0.51, P = 0.02). Intraoperative rupture occurred in 3%, and temporary clipping was performed in 15%. Clinical vasospasm occurred in 43 patients with ruptured aneurysms (50.6%). Overall, mortality was 26%; 25 patients in the ruptured group (29.4%) and one in the unruptured group (6%). The Glasgow Outcome Scale (GOS) was favorable (GOS 4 or 5) in 54% of patients, significantly more so in those with unruptured aneurysms (P = 0.01). In patients with ruptured aneurysms, mortality was associated with preoperative Hunt and Hess (HH) score (P < 0.001), hydrocephalus (P < 0.001), and clinical complications (P < 0.001). Unfavorable outcomes were associated with HH score (P < 0.001), Fisher grade (P = 0.015), clinical vasospasm (P = 0.012), external ventricular drain (P = 0.015), hydrocephalus (P < 0.001), and presence of clinical complications (P = 0.001). In patients with unruptured aneurysms, presence of clinical complications was the only factor associated with mortality (P < 0.001).

Conclusion:

Despite advances in the management of subarachnoid hemorrhage and surgical treatment of aneurysms, mortality is still high, especially due to clinical complications.

"Live Cadaver" Model for Internal Carotid Artery Injury Simulation in Endoscopic Endonasal Skull Base Surgery

BACKGROUND

Intraoperative injury of the internal carotid artery (ICA) is the most dreaded complication in endoscopic endonasal surgery (EES) of skull base. Training for ICA injury is practically impossible in live operative settings.

OBJECTIVE

To evaluate a pulsatile perfusion-based live cadaveric model for ICA injury simulation in a laboratory setting. The major emphasis of the study was to evaluate various means of controlling acute bleeding and evaluating the practical utility of this model for training purposes.

METHODS

Five embalmed, uninjected cadaveric heads were prepared for study by connecting to a pulsatile perfusion pump system filled with artificial blood solution. EES approaches were used to evaluate different types of ICA injuries similar to operative scenarios. Various methods of managing ICA injuries such as packing, clipping, and trapping, were evaluated. The educational advantages of the live cadaver model were assessed using questionnaires given to participants in a hands-on dissection course.

RESULTS

The trainee was faced with several scenarios similar to those encountered during an actual intraoperative ICA injury. Packing, clipping, and trapping of the ICA injury were successfully achieved in all segments of the ICA. Clip-based reconstruction techniques were successfully developed. All trainees reported gaining new knowledge, learning new techniques. The responses to the questionnaire confirmed the significant educational value of this model.

CONCLUSION

The live cadaver model presented here provides real-life experience with major vessel injury during EES in a laboratory setting. This model could significantly improve current training for the management of intraoperative vascular injuries during EES.

Comparison of flow diversion with clipping and coiling for the treatment of paraclinoid aneurysms in 115 patients

OBJECTIVE

Paraclinoid aneurysms represent approximately 5% of intracranial aneurysms (Drake et al. [1968]). Visual impairment, which occurs in 16%-40% of patients, is among the most common presentations of these aneurysms (Day [1990], Lai and Morgan [2013], Sahlein et al. [2015], and Silva et al. [2017]). Flow-diverting stents, such as the Pipeline Embolization Device (PED), are increasingly used to treat these aneurysms, in part because of their theoretical reduction of mass effect (Fiorella et al. [2009]). Limited data on paraclinoid aneurysms treated with a PED exist, and few studies have compared outcomes of patients after PED placement with those of patients after clipping or coiling.

METHODS

The authors performed a retrospective analysis of 115 patients with an aneurysm of the cavernous to ophthalmic segments of the internal carotid artery treated with clipping, coiling, or PED deployment between January 2011 and March 2017. Postoperative complications were defined as new neurological deficit, aneurysm rupture, recanalization, or other any operative complication that required reintervention.

RESULTS

A total of 125 paraclinoid aneurysms in 115 patients were treated, including 70 with PED placement, 23 with coiling, and 32 with clipping. Eighteen (14%) aneurysms were ruptured. The mean aneurysm size was 8.2 mm, and the mean follow-up duration was 18.4 months. Most aneurysms were discovered incidentally, but visual impairment, which occurred in 21 (18%) patients, was the most common presenting symptom. Among these patients, 15 (71%) experienced improvement in their visual symptoms after treatment, including 14 (93%) of these 15 patients who were treated with PED deployment. Complete angiographic occlusion was achieved in 89% of the patients. Complications were seen in 17 (15%) patients, including 10 (16%) after PED placement, 2 (9%) after coiling, and 5 (17%) after clipping. Patients with incomplete aneurysm occlusion had a higher rate of procedural complications than those with complete occlusion (p = 0.02). The rate of postoperative visual improvement was significantly higher among patients treated with PED deployment than in those treated with coiling (p = 0.01). The significant predictors of procedural complications were incomplete occlusion (p = 0.03), hypertension, (p = 0.04), and diabetes (p = 0.03).

CONCLUSIONS

In a large series in which patient outcomes after treatment of paraclinoid aneurysms were compared, the authors found a high rate of aneurysm occlusion and a comparable rate of procedural complications among patients treated with PED placement compared with the rates among those who underwent clipping or coiling. For patients who presented with visual symptoms, those treated with PED placement had the highest rate of visual improvement. The results of this study suggest that the PED is an effective and safe modality for treating paraclinoid aneurysms, especially for patients who present with visual symptoms.

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.

Surgical Training for the Management of Intraoperative Aneurysm Rupture Using a Three-Dimensional Artificial Model

Background

Intraoperative aneurysm rupture (IAR) is one of the most dreaded complications of microsurgical cerebral aneurysm clipping. The surgical result is directly affected by whether an operator can control IAR. However, the development of endovascular treatment has decreased the probability of exposure to this situation for neurosurgical residents. Therefore, neurovascular surgeons must develop the skills and mental attitude to deal with IAR through off-the-job training, without conducting actual operations.

Materials and Methods

We have developed a tabletop training system using three-dimensional artificial modeling that can be used for daily clinical practice.

Results and Conclusions

Our model is useful for training because of its low cost, reusability, and ease of preparation and practice.

A Median Artery of the Corpus Callosum

The anterior communicating artery is one of the main components of the vascular network that delivers blood to the brain. Therefore, a good understanding of the normal anatomy and its variations is important to neurologists, neurosurgeons, and other health care providers dealing with the central nervous system. Here, we present a case of a median artery of the corpus callosum found in a cadaver, with consideration of cerebral hemodynamics implications.

Application of Micromirror in Microsurgical Clipping to the Intracranial Aneurysms

OBJECTIVE

The aim of the study was to explore the values and disadvantages of micromirror in the intracranial aneurysm clipping surgery.

METHODS

Micromirror was used to assist microsurgical clipping to 36 intracranial aneurysms in 31 patients, of which 3 were carotid-ophthalmic artery aneurysms, 3 were anterior choroidal artery aneurysms, 11 were posterior communicating artery aneurysms, 7 were middle cerebral artery aneurysms, 10 were anterior communicating artery or anterior cerebral artery aneurysms, and the rest were a posterior cerebral artery aneurysm and a posterior inferior cerebellar artery aneurysm. The micromirror was used before and after clipping to observe the anatomic features of necks hidden behind and medial to aneurysms, to visualize surrounding neurovascular structures, and to verify the optimal clipping position. Intraoperative indocyanine green fluorescein angiography, postoperative computerized tomography angiography, and digital subtraction angiography confirmed the success of sufficient clipping.

RESULTS

Intraoperative indocyanine green angiography, postoperative computerized tomography angiography , or digital subtraction angiography were performed and showed no case of wrong or insufficient clipping of aneurysm.

CONCLUSIONS

Micromirror-assisted microsurgical clipping to the intracranial aneurysm is safe, sufficient, convenient, and practical.

Intraoperative Aneurysm Rupture During Microsurgical Clipping: Risk Re-evaluation in the Post-International Subarachnoid Aneurysm Trial Era

OBJECTIVES

Intraoperative aneurysm rupture (IOAR) is a common complication during intracranial aneurysm (IA) surgery. In light of the paradigm shift regarding IA selected for clipping in the post-International Subarachnoid Aneurysm Trial (ISAT) era, we aimed to evaluate the risk factors and effects of IOAR in an institutional series of clipped ruptured IA (RIA) and unruptured IA (UIA).

MATERIAL AND METHODS

All IAs treated with microsurgical clipping at our institution between 2003 and 2016 were eligible for this study. Demographic, clinical, and radiographic factors were correlated with occurrence of IOAR in univariate and multivariate analyses. The effect on outcome was analyzed for RIA and UIA separately.

RESULTS

Nine hundred and three clipped IAs were included in the final analysis (538 UIA and 365 RIA). IOAR occurred in 163 cases (18.1%), mostly during clipping of RIA (37.5% vs. 4.8%) In multivariate analysis, ruptured status (adjusted odds ratio [aOR], 10.46; P < 0.001), sack size (aOR, 1.05 per mm increase; P = 0.038) and IA location in the anterior communicating artery (aOR, 2.31; P < 0.001) independently predicted IOAR. For RIA cases, IOAR was also independently predicted by rebleeding before therapy (aOR, 3.11; P = 0.033) and clinical severity of subarachnoid hemorrhage (aOR, 1.18 per WFNS grade increase; P = 0.049). IOAR independently predicted poor outcome (aOR, 1.83; P = 0.042) after RIA surgery. In turn, IOAR affected only the risk for cerebral infarct (OR, 3.75; P = 0.003) and incomplete IA occlusion (OR, 3.45; P = 0.003) for UIA cases, but not the outcome (P = 0.263).

CONCLUSIONS

IOAR was independently predicted by the ruptured status, location, and size of IA and by initial severity of aneurysmal bleeding and pretreatment rebleeding. The influence of IOAR differed between RIA and UIA cases.

The role of wall shear stress in the parent artery as an independent variable in the formation status of anterior communicating artery aneurysms

OBJECTIVES

The study aimed to determine which hemodynamic parameters independently characterize anterior communicating artery (AcomA) aneurysm formation and explore the threshold of wall shear stress (WSS) of the parent artery to better illustrate the correlation between the magnitude of WSS and AcomA aneurysm formation.

METHODS

Eighty-one patients with AcomA aneurysms and 118 patients without intracranial aneurysms (control population), as confirmed by digital subtraction angiography (DSA) from January 2014 to May 2017, were included in this cross-sectional study. Three-dimensional-DSA was performed to evaluate the morphologic characteristics of AcomA aneurysms. Local hemodynamic parameters were obtained using transcranial color-coded duplex (TCCD). Multivariate logistic regression and a two-piecewise linear regression model were used to determine which hemodynamic parameters are independent predictors of AcomA aneurysm formation and identify the threshold effect of WSS of the parent artery with respect to AcomA aneurysm formation.

RESULTS

Univariate analyses showed that the WSS (p < 0.0001), angle between the A1 and A2 segments of the anterior cerebral artery (ACA) (p < 0.001), hypertension (grade II) (p = 0.007), fasting blood glucose (FBG; > 6.0 mmol/L) (p = 0.005), and dominant A1 (p < 0.001) were the significant parameters. Multivariate analyses showed a significant association between WSS of the parent artery and AcomA aneurysm formation (p = 0.0001). WSS of the parent artery (7.8-12.3 dyne/cm²) had a significant association between WSS and aneurysm formation (HR 2.0, 95% CI 1.3-2.8, p < 0.001).

CONCLUSIONS

WSS ranging between 7.8 and 12.3 dyne/cm² independently characterizes AcomA aneurysm formation. With each additional unit of WSS, there was a one-fold increase in the risk of AcomA aneurysm formation.

KEY POINTS

• Multivariate analyses and a two-piecewise linear regression model were used to evaluate the risk factors for AcomA aneurysm formation and the threshold effect of WSS on AcomA aneurysm formation. • WSS ranging between 7.8 and 12.3 dyne/cm ² was shown to be a reliable hemodynamic parameter in the formation of AcomA aneurysms. The probability of AcomA aneurysm formation increased one-fold for each additional unit of WSS. • An ultrasound-based TCCD technique is a simple and accessible noninvasive method for detecting WSS in vivo; thus, it can be applied as a screening tool for evaluating the probability of aneurysm formation in primary care facilities and community hospitals because of the relatively low resource intensity.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Flow-diverter stents for endovascular management of non-fetal posterior communicating artery aneurysms-analysis on aneurysm occlusion, vessel patency, and patient outcome

Background Use of flow-diversion technology in the treatment of incidental and recanalized posterior communicating artery (PComA) aneurysms. Methods Patients treated with the Pipeline embolization device (PED) for PComA aneurysms were identified and included in our retrospective analysis. We evaluated aneurysm characteristics, modified Rankin Scale score (mRS) on admission, angiography follow-up, and patient clinical outcome at discharge, at three to nine months, and at 12-18 months. Results We included 56 patients with a mean age of 56 years. Median mRS on admission was 0. All aneurysms involved the PComA and were either new findings or found to have shown recanalization at angiography follow-up from previous coil embolization or surgical clipping. Intraprocedural device foreshortening was observed in one case requiring additional placement of a self-expanding stent. One intraprocedural aneurysm rupture occurred because of a broken distal wire. This patient had an mRS of 4 after the procedure. Three- to nine-month and 12- to 18-month follow-up angiography showed near complete or complete aneurysm occlusion in most cases. Minimal to mild intimal hyperplasia was seen in five cases at three to nine months. PComA patency over time showed 29 of 46 initially patent vessels still patent at six months. Thirteen and seven PComAs showed progressive decrease in flow at three to nine months and 12-18 months, respectively. Median mRS remained 0 for all patients at three- to nine-month and 12- to 18-month follow-up. Conclusions Our preliminary results show that flow-diversion technology is an effective and safe treatment option. Larger studies with long-term follow-up are needed to validate our promising results.

Flow Diverters for Treatment of 160 Ophthalmic Segment Aneurysms: Evaluation of Safety and Efficacy in a Multicenter Cohort

BACKGROUND

Treatment of ophthalmic segment aneurysms (OSA) remains challenging. Flow diverter stents (FDS) have evolved as a promising endovascular treatment option for aneurysms of the internal carotid artery and are associated with high occlusion rates and a favorable morbidity and mortality profile.

OBJECTIVE

To determine safety and efficacy of FDS for OSA in a large, multicenter cohort.

METHODS

A retrospective analysis of prospectively maintained databases of 127 consecutive patients harboring 160 OSA treated with FDS was performed. Aneurysms were classified based on location and morphology. Follow-up with digital subtraction angiography (DSA) was performed 6 to 18 months after treatment.

RESULTS

Follow-up DSA was available for 101 (63.1%) aneurysms with a mean follow-up of 18 months. Complete occlusion was observed in 90 aneurysms (89.1%), near-complete occlusion (>95%) in 3 (3%), and incomplete occlusion (<95%) in 8 aneurysms (7.9%). One aneurysm was retreated with another FDS (0.9%). No risk factors for incomplete occlusion were identified. The OA was occluded at the latest follow-up in 6 cases (7.1%). Permanent morbidity occurred in 4 patients (3.1%), and there was no mortality related to the FDS procedure.

CONCLUSION

Treatment of OSA with FDS was found to be safe and effective. The retreatment rate was extremely low and aneurysms that occluded did not reanalyze.

Intraoperative Rupture Cerebral Aneurysm and Computational Flow Dynamics

Intraoperative aneurysmal rupture (IAR) is the most fearsome complication of aneurysm surgery. IAR associates with high morbidity and mortality. In recent years, we have many studies regarding using computational fluid dynamics (CFD) in aneurysm surgery. CFD helps in calculating the velocity of blood flowing in the aneurysm sac, the pressure in the aneurysm sac, and wall shear stress (WSS). CFD also helps in predicting nature of aneurysm wall and thus may warn about different intraoperative microscopy findings in aneurysms. Using its application, surgeon may become more careful in doing microsurgical sharp dissection. A 40-year-old female admitted with diagnosis of unruptured anterior communicating artery aneurysm. CFD analysis demonstrated high intra-aneurysmal pressure and divergent WSS in dome. During sharp dissection, there was intraoperative rupture aneurysm twice which was managed with cotton tamponade and glue and temporary clipping aneurysm. Indocyanine green video angiography showed working parent arteries and nonfunctioning aneurysm. After operation, the patient recovered fully and had a modified Rankin score of 1. This case demonstrated importance of preoperative planning of aneurysm surgery using CFD analysis. IAR is associated with an increased risk for an unfavorable outcome. Accurate preoperative planning with studying flow dynamics and structure of aneurysm may help in use sharp microsurgical dissection more cautiously.

Surgical Outcome of Very Small Intracranial Aneurysms Utilizing the Double Clip Technique

OBJECTIVES

To report the outcome of patients with very small intracranial aneurysm (VSIA) undergoing surgical clipping using a double-clip technique.

METHODS

This cross-sectional study was conducted in Namazi Hospital, the main referral neurovascular center in Southern Iran during a 6-year period from September 2010 to March 2016. All patients with VSIAs (≤3 mm) undergoing surgery with double-clip technique were included. This technique reduces the clip slippage. The short- and long-term outcomes determined by Glasgow outcome score (GOS), modified Rankin Scale (MRS), and complications.

RESULTS

Operations were performed on 32 VSIAs in 26 patients with a mean ± SD age of 55.7 ± 10.1 years. Middle cerebral artery was the most common location for VSIA (50.0%). There was no neck remnant, and the complete occlusion rate was 100%. The rate of intraoperative aneurysm rupture was 30.8%, and none of the patients experienced rebleeding. The 6-month mortality rate was 0% in ruptured VSIAs and 6.25% in unruptured VSIAs. Most of the patients had favorable outcomes (88.5%), and the overall mortality rate was 11.5%. The rate of permanent neurologic deficit was 10.0% in ruptured and 12.5% in unruptured VSIAs. Multivariate logistic regression analysis revealed no association between baseline and clinical characteristics and outcome in this series.

CONCLUSION

VSIAs are difficult to treat because of their small sizes; therefore, with a double-clip technique, one can reduce complications related to the treatment of small aneurysms.

Symptomatic and silent cerebral infarction following surgical clipping of unruptured intracranial aneurysms: incidence, risk factors, and clinical outcome

Cerebral infarction (CI) associated with clipping of unruptured intracranial aneurysms (UIAs) has not been completely studied. The role of individual and operative characteristics is not known, and the risk of silent CI has not been well described. To determine the incidence, risk factors, and clinical outcome of postoperative CI, we retrospectively analyzed 388 consecutive patients undergoing clipping of UIAs between January 2012 and December 2015. We reviewed the pre- and postoperative computed tomography (CT) images of each patient. Postoperative CI was defined as a new parenchymal hypodensity in the vascular territory of treated artery. Patient-specific, aneurysm-specific, and operative variables were analyzed as potential risk factors. Functional outcome at discharge was assessed with the modified Rankin Scale (mRS). Postoperative CI was found in 49 (12.6%) patients, 29 of whom manifested neurological deficits. The incidences of symptomatic stroke and silent CI were 7.5 and 5.2%, respectively. Multivariate analysis showed that larger aneurysm size and history of hypertension were significantly associated with CI. Disability (mRS > 2) rate was 42.9% among patients with CI, which was substantially higher than that among patients without (0.9%). In conclusion, the incidence of CI following clipping of UIAs was not low. Larger aneurysm size and history of hypertension were independent risk factors. Postoperative symptomatic stroke correlated with an extremely high risk of disability. Silent CI was seemingly nondisabling, but the possible cognitive consequence is pending.

Simple Lateral Suboccipital Approach and Modification for Vertebral Artery Aneurysms: A Study of 52 Cases Over 10 Years

INTRODUCTION

Complex skull base approaches are frequently used to treat intracranial vertebral artery (VA) and proximal posterior inferior cerebellar artery (PICA) aneurysms. These complex procedures are associated with higher risk of neurovascular injury. Hence, a less-invasive surgical approach is needed to improve the efficacy and safety of treatment.

METHODS

A retrospective analysis was conducted on clinical and radiologic data from surgeries in which simple lateral suboccipital and "lateral-enough" approaches were used to clip VA aneurysms in the Department of Neurosurgery at Helsinki University Central Hospital from 2000 to 2009.

RESULTS

Fifty-two VA or PICA aneurysms were treated using the simple lateral suboccipital approach. Sixteen patients (31%) presented with an unruptured aneurysm, 21 patients (40%) with World Federation of Neurosurgical Societies (WFNS) grade 1-3, and 15 patients (29%) with World Federation of Neurosurgical Societies grade 4-5. The aneurysms were saccular in 48 cases (92%), dissecting in 3 cases (6%), and fusiform in 1 case (2%). The most common aneurysm location was the VA-PICA junction (81%). The mean final modified Rankin Scale score was 2, and in unruptured cases, all patients had favorable clinical outcomes. The main causes of unfavorable outcome were poor preoperative clinical grade (P = 0.002), preoperative intraventricular hemorrhage (P = 0.008), postoperative hydrocephalus (P = 0.003), brain infarction (P = 0.005), and postoperative pneumonia (P < 0.001).

CONCLUSIONS

We describe a 10-year experience using a simple lateral suboccipital approach and its modification by the senior author (J.H.) to treat VA and proximal PICA aneurysms. Unfavorable outcome was related to the poor preoperative clinical grade, preoperative intraventricular hemorrhage, and postoperative pneumonia.