Intraoperative neuromonitoring during microsurgical clipping for unruptured anterior choroidal artery aneurysm

Treatment Outcomes in Patients with Unruptured Anterior Choroidal Artery Aneurysms: A Single-Center Experience

Objective

Treatment of anterior choroidal artery (AChA) aneurysms is frequently associated with ischemic complications. This study aimed to report the outcomes of treatment of unruptured AChA aneurysms in our hospital.

Methods

Between January 2015 and March 2022, 40 patients were treated for an unruptured AChA aneurysm in our hospital. Age, sex, aneurysm size, AChA branching type, treatment, occlusion rate, complications, modified Rankin Scale (mRS) score before surgery and after 90 days, and recurrence were investigated. The branching type was classified as internal carotid artery (ICA), neck, or dome type based on the location of the AChA origin.

Results

The mean age was 61.1 ± 1.9 years; 15 patients were men and 25 were women. The mean aneurysm diameter was 4.4 ± 0.3 mm. The branching type was ICA in four patients, neck in 35, and dome in one. Treatment was surgical clipping in 22 patients and endovascular coil embolization in 18 (14 with stent assistance). Motor-evoked potential (MEP) monitoring was used in all patients of the clipping group and 9 cases of the coiling group. Treatment complications occurred in eight patients (20%). mRS score worsened by more than one point 90 days after treatment in four patients (10%); however, the proportion of patients who experienced this did not significantly differ between the clipping and coiling groups. Although the odds of a thrombotic complication were higher with coiling than clipping, the difference was not significant (odds ratio: 10.2; P = 0.08). The rate of complete occlusion was lower in the coiling group (72.2% vs. 95.3%), but the difference was not significant. The median follow-up was 696 days (range: 99-2053). No aneurysm recurrence or rupture occurred.

Conclusion

AChA branching type is important for treatment decision-making in patients with AChA aneurysms. Rates of complications and occlusion do not significantly differ between clipping and coiling of AChA aneurysms. MEP monitoring may be useful in preventing thrombotic complications during coil embolization.

Anterior Choroidal Artery Aneurysm Clipping: Angiographic Diagnostics and Surgical Tactics Focused on Visualizing the Anterior Choroidal Artery Behind the Aneurysm

OBJECTIVE

This study describes our experiences with anterior choroidal artery (AChA) aneurysm clipping with a focus on visualizing the AChA just behind the aneurysm to identify the risk factors for adhesion of the AChA or its branches to the posterior wall of the AChA aneurysm.

METHODS

The initial segment of the AChA just behind the aneurysm was evaluated preoperatively using three-dimensional (3D) rotational angiography, and its course was designated as posteromedial, posterior, or posterolateral. The posterior aspect of the AChA aneurysm was inspected intraoperatively using an endoscope or micromirror.

RESULTS

Based on 3D rotational angiography, the main trunk of the AChA showed a posteromedial (n = 47, 57.3%), posterior (n = 18, 22.0%), or posterolateral (n = 17, 20.7%) course just behind the aneurysm. Intraoperatively, 14.6% (12 of 82) of the clipped AChA aneurysms revealed an AChA branch adhered to the posterior wall of the aneurysm. A multivariate analysis revealed that the posterior or posterolateral course of the initial segment of the AChA was a statistically significant risk factor for adhesion of an AChA branch to the posterior wall of the aneurysm (odds ratio [OR] 21.083, 95% confidence interval [CI] 2.567-173.166, P = 0.005).

CONCLUSIONS

The initial course of the AChA just behind an AChA aneurysm can be evaluated using 3D rotational angiography. In contrast to a posteromedial course, a posterior or posterolateral course of the AChA just behind an AChA aneurysm can be a significant risk factor for adhesion of an AChA branch to the posterior wall of an AChA aneurysm.

Clipping of Unruptured Anterior Choroidal Artery Aneurysms Together with Small Branches: Safety Confirmation Using Intraoperative Indocyanine Green Video-Angiography and Intraoperative Neurophysiological Monitoring

BACKGROUND

In treating anterior choroidal artery (AChA) aneurysms, preserving the AChA main trunk is of course necessary to prevent postoperative ischemic complications. However, in practice, complete occlusions are often limited by small branches.

OBJECTIVE

We aimed to demonstrate that even in cases where complete occlusion of the AChA aneurysm is complex due to small branches, complete occlusion can be safely achieved using indocyanine green video-angiography and intraoperative neurophysiological monitoring (IONM).

METHODS

We performed a retrospective review of all unruptured AChA aneurysms surgically treated at our institution from 2012 to 2021. All available surgical videos were reviewed to find AChA aneurysms clipped with small branches; clinical and radiological data were collected for these cases.

RESULTS

Among 391 cases of unruptured AChA aneurysms treated surgically, 25 AChA aneurysms were clipped with small branches. AChA-related ischemic complications occurred in 2 cases (8%) without retrograde indocyanine green filling to the branches. These 2 cases had changes in IONM. There were no ischemic complications in the remaining cases with retrograde indocyanine green filling to the branches and no change in IONM. During an average follow-up of 47 months (12-111 months), a small residual neck was observed in 3 cases (12%) and recurrence or progression of the aneurysm was observed in only 1 case (4%).

CONCLUSIONS

The surgical treatment of AChA aneurysms carries the risk of devastating ischemic complications. Even in cases where complete clip ligation seems impossible due to small branches associated with AChA aneurysms, complete occlusion can be safely achieved using indocyanine green video-angiography and IONM.

Comparison of outcomes between clipping and endovascular coiling in anterior choroidal artery aneurysm: a systematic review

SAH (subarachnoid hemorrhage) caused by aneurysm rupture has the greatest mortality rate, with nearly 50% of patients unable to survive beyond 1 month after the attack. Anterior choroidal artery (AChA) aneurysms are one of the most difficult to treat among the numerous types of aneurysms. Until now, some neurosurgeons employed shearing while others employed coiling. In this trial, researchers will compare surgical clipping and endovascular coiling treatments for anterior choroidal artery aneurysms in terms of mortality, rebleeding, retreatment, and post-procedure outcomes. Using the PubMed electronic database, the Cochrane library, the Medline Database, the Directory of Open Access Journals, and EBSCHOHOST, a systematic review compared surgical clipping and endovascular coiling in all cases of choroidal artery aneurysm. There were 17 studies that met the eligibility requirements, with a total of 1486 patients divided into groups that underwent clipping (1106) or endovascular coiling (380). The mortality rate for clipping is 1.8%, while the mortality rate for endovascular coiling is 2.34%. Rebleeding occurs in 0% of patients undergoing endovascular coiling and 0.73% of patients undergoing clipping. Retreatment of clipping was 0.27%, while endovascular coiling was 3.42%. Post-complication procedures occurred in 11.12% of patients undergoing endovascular clipping and 15.78% of patients undergoing endovascular coiling. The intervention technique of clipping has a reduced rate of mortality, reoperation, and post-operative complications. Endovascular coiling results in a reduced rate of rebleeding than clipping.

Usefulness of Transcranial Motor Evoked Potential in Clipping Surgery for Cerebral Aneurysms-Introduction of a New Protocol for Stable Monitoring

The usefulness of transcranial motor evoked potentials (Tc-MEPs) in clipping surgery has been reported. However, numerous false positive and false negative cases were reported. We report the usefulness of a new protocol compared with direct cortical MEP (Dc-MEP).Materials were 351 patients who underwent aneurysmal clipping under simultaneous monitoring of Tc- and Dc-MEPs. A total of 337 patients without hemiparesis and 14 with hemiparesis were separately analyzed. Intraoperative changes of Tc-MEP thresholds were examined in the first 50 patients without hemiparesis. The stimulation strength of Tc-MEP was set at +20% of the stimulation threshold. As thresholds changed intraoperatively, thresholds were examined every 10 min and changed stimulation strength.Stimulation thresholds of Tc-MEP were significantly decreased after craniotomy and significantly increased after CSF aspiration. The recording ratios of Tc- and Dc-MEPs were 98.8% and 90.5%, respectively. Out of 304 patients without MEP change, 5 patients developed transient or mild hemiparesis with infarction of the territory of the perforating artery arising from the posterior communicating artery. Out of 31 patients whose MEP transiently disappeared, 3 patients developed transient or mild hemiparesis. The other two patients without MEP recovery manifested persistent hemiparesis. In 14 patients with preoperative hemiparesis, 3 patients whose healthy/affected ratio of Tc-MEP was large developed severe persistent hemiparesis.We clarified the intraoperative changes of Tc-MEP thresholds for the first time. A new protocol of Tc-MEP that followed thresholds and changed stimulation strength to +20% of thresholds is useful for stable monitoring. The usefulness of Tc-MEP is the same as that or better than that of Dc-MEP.

Treatment of Ruptured Anterior Choroidal Artery Aneurysms by Acute Coiling Followed by Flow Diversion

BACKGROUND

Flow-diverter treatments are successful endovascular treatments in protecting important perforating branches during aneurysm treatments. Because these treatments are performed under antiplatelet therapy, acute flow-diverter treatments in ruptured aneurysms are still controversial. Acute coiling followed by flow diversion has emerged as an intriguing and feasible treatment option for ruptured anterior choroidal artery aneurysm treatment. As a single-center retrospective case series study, this study reported the clinical and angiographic results of staged endovascular treatment in patients with a ruptured anterior choroidal aneurysm.

METHODS

This is a single-center retrospective case series study between March 2011 and May 2021. Patients with ruptured anterior choroidal aneurysm received flow-diverter therapy in a different session after acute coiling. Patients treated with primary coiling or only flow diversion were excluded. Preoperative demographic and presenting symptoms, aneurysm morphology, perioperative and postoperative complications, and long-term clinical and angiographic outcome as measured using the modified Rankin Scale and O'Kelly Morata Grading scale and also Raymond-Roy occlusion classification respectively.

RESULTS

Sixteen patients underwent coiling in the acute phase to undergo flow diversion later. The mean maximum aneurysm diameter is 5.44 ± 3.39 mm. All patients had a subarachnoid hemorrhage and were treated acutely between days 0 and 3 of acute bleeding. The mean age at the presentation was 54.12 ± 12 years (32-73 years). Two patients (12.5%) had minor ischemic complications, which are seen on magnetic resonance angiography as clinically silent infarcts, after the procedure. One patient (6.2%) had a technical complication with the flow-diverter shortening and deployed a second flow diverter telescopically. No mortality or permanent morbidity was reported. The mean interval time between the 2 treatments was 24.06 ± 11.83 days. All patients were followed up with digital subtraction angiography; 14/16 patients (87.5%) had aneurysms that were completely occluded and 2/16 (12.5%) showed near-complete occlusion. Mean follow-up was 16.62 ± 3.22 months; all patients had modified Rankin Scale scores ≤2; 14/16 (87.5%) had a total occlusion 14/16 (87.5%) had near-complete occlusion. None of the patients had retreatment or rebleeding.

CONCLUSIONS

Staged treatment of ruptured anterior choroidal artery aneurysms with acute coiling and flow-diverter treatment after recovery from subarachnoid hemorrhage is safe and effective. In this series, no cases of rebleeding occurred during the interval between coiling and flow diversion. Staged treatment should be considered a valid option in patients with challenging ruptured anterior choroidal aneurysms.

Necessity of Mandatory Postoperative Intensive Care Unit Management after Clipping Surgery for Unruptured Intracranial Aneurysms

OBJECTIVE

Many neurosurgeons routinely perform postoperative intensive care unit (ICU) management after clipping of unruptured intracranial aneurysms (UIAs). However, whether routine postoperative ICU care is necessary remains a clinical question. Therefore, we investigated which factors acted as risk factors that actually required ICU care after microsurgical clipping of unruptured aneurysms.

METHODS

We included a total of 532 patients who underwent clipping surgery for UIA between January 2020 and December 2020. The patients were divided into two groups: those who really required ICU care (41 patients, 7.7%) and those who did not (491 patients, 92.3%). A backward stepwise logistic regression model was used to identify factors that were independently associated with ICU care requirement.

RESULTS

The mean hospital stay duration and the operation time were significantly longer in the ICU requirement group than in the no ICU requirement group (9.9 ± 10.7 vs. 6.3 ± 3.7 days, p = 0.041), (259.9 ± 128.4 vs. 210.5 ± 46.1 min, p = 0.019). The transfusion rate was significantly higher (p = 0.024) in the ICU requirement group. Multivariable logistic regression analysis identified male sex (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.15-4.76; p = 0.0195), operation time (OR, 1.01; 95% CI, 1.00-1.01; p = 0.0022), and transfusion (OR, 2.35; 95% CI, 1.00-5.51; p = 0.0500) as independent risk factors for requiring ICU care after clipping.

CONCLUSIONS

Postoperative ICU management may not be mandatory after clipping surgery for UIAs. Our results suggest that postoperative ICU management may be more required in the male sex, patients with longer operation times, and those who received a transfusion.

Treatment results of anterior choroidal artery aneurysms treated mostly with coil embolization: A single-center experience

BACKGROUND

Anterior choroidal artery (AchA) aneurysms are usually small in diameter because of the size of the involved artery and are often wide-necked. Coil embolization of AchA aneurysm is thus challenging because of serious risks, such as thromboembolic occlusion of artery and perforation of aneurysm dome. Therefore, aneurysmal neck clipping remains widely performed despite a recent increase in the use of coil embolization for aneurysm treatment. We report the treatment results of AchA aneurysms mostly (92.3%) treated with coil embolization at our institute.

METHODS

The database and medical records of patients who underwent coil embolization for AchA aneurysms were retrospectively analyzed. The clinical and imaging results and procedure-related complications were investigated after coil embolization performed between January 2006 and March 2022 at our institute.

RESULTS

In total, 96 AchA aneurysms comprising 65 unruptured and 31 ruptured aneurysms, including only 1 ruptured aneurysm (1.0%) re-embolized at postoperative day 192 because of coil compaction, were evaluated. After the initial coil embolization, complete occlusion was attained in 41, residual neck in 45, and residual aneurysm in 10 patients. Follow-up radiological studies after 6-174 months were performed for 80 aneurysms. Complete occlusion was noted in 57 patients, residual neck in 22, and residual aneurysm in 1. The dysarthria experienced by one (1.0%) patient was the only symptomatic procedure-related complication. After coil embolization, neither delayed new rupture nor re-rupture was observed.

CONCLUSIONS

The results of this study demonstrate that coil embolization is a safe and effective treatment option for patients with AchA aneurysms.

Clinical Usage of Different Doses of Cis-Atracurium in Intracranial Aneurysm Surgery and Its Effect on Motor-Evoked Potentials

The objective of this work was to investigate the effect of different doses of cis-atracurium on patients undergoing general anesthesia induction (GAI) during intracranial aneurysm surgery (ICAS). In this work, 90 patients who underwent ICAS under the elective motor-evoked potential (MEP) monitoring in the First Affiliated Hospital of Northwest University (Xi'an No. 1 Hospital) from January 2021 to May 2022 were enrolled as the research objects. Randomly, they were rolled into a S1 group (30 cases, 2 times 95% effective dose (ED95) cis-atracurium), a S2 group (30 cases, 3 times ED95 cis-atracurium), and a S3 group (30 cases, 4 times ED95 cis-atracurium). The endotracheal intubation conditions, the train-of-four (TOF) rate (TOFR), body movement, and spontaneous breathing were compared among the three groups of patients. The results showed that the MEP inhibition time of the patients in the S3 group was much longer than that of the S1 and S2 groups, but it showed no significant difference between the S1 group and S2 group (P > 0.05). The good rates of endotracheal intubation conditions in the S2 group (100%) and S3 group (100%) were obviously higher than the rate in the S1 group (43.33%). The TOFRs of patients in S2 and S3 groups at time t2 and t3 were lower obviously to that at time t0, while the TOFRs of patients in S3 group at time t2 and t3 were still lower in contrast to the S2 group (P < 0.05). The mean arterial pressure (MAP) and heart rate (HR) of patients in all groups were lower at t1, t2, and t3 than at t0 (P < 0.05), while the differences among different groups were not remarkable (P > 0.05). Finally, using 3 times ED95 cis-atracurium for GAI could reduce the risk of intraoperative body movement and spontaneous breathing, as well as the residual degree of muscle relaxation, in patients with ICAS, without affecting MEP monitoring, improving endotracheal intubation conditions, and increasing safety during open neurosurgery operations.

Evaluation of multimodal intraoperative neurophysiologic monitoring during supratentorial aneurysm surgery: a comparative study

The objective of this study is to determine the role of multimodal intraoperative neurophysiologic monitoring (IONM) in the overall outcome of intracranial aneurysms surgery, and the risk factors associated with ischemic complications. We grouped 268 ruptured and unruptured intracranial aneurysms surgically treated at our institution into 2 cohorts, based on the use of IONM (180; 67.16%) or non-use of IONM (88; 32.84%). The IONM technique used was multimodal: electroencephalogram (EEG), somatosensory evoked potentials (SSEPs), transcranial (TES), and direct cortical (DCS) stimulation motor evoked potentials (MEPs). There was a significant difference, with a reduction in perioperative strokes (p = 0.011) and better motor surgery-related outcome in the IONM group (p = 0.016). Independent risk factors identified for surgery ischemic complications were temporary clipping time ≥ 6'05″ (odds ratio [OR]: 3.03; 95% CI: 1.068-8.601; p = 0.037), aneurysm size ≥ 7.5 mm (OR: 2.65; 95% CI: 1.127-6.235; p = 0.026), and non-use of IONM (OR: 2.79; 95% CI: 1.171-6.636; p = 0.021). Conversely, aneurysm rupture was not detected as an independent risk factor (OR: 2.5; 95% CI: 0.55-4.55; p = 0.4). Longer temporary clipping time, larger aneurysm size, and the non-use of IONM could be considered as risk factors for ischemic complications during microsurgical clipping. A standardized designed protocol including multimodal IONM with DCS provides continuous information about blood supply and allows reduction of treatment-related morbidity. Multimodal IONM is a valuable technique in intracranial aneurysm surgery.

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

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

Intravenous Fluid Selection for Unruptured Intracranial Aneurysm Clipping : Balanced Crystalloid versus Normal Saline

OBJECTIVE

While balanced crystalloid (BC) could be a relevant fluid regimen with buffer system compared with normal saline (NS), there have been no studies on the optimal fluid for surgery of an unruptured intracranial aneurysm (UIA). This study aimed to compare the effects of fluid regimens between NS and BC on the metabolic and clinical outcomes of patients who underwent surgery for UIA.

METHODS

This study was designed as a propensity score matched retrospective comparative study and included adult patients who underwent UIA clipping. Patient groups were categorized as NS and BC groups based on the types of pre-operative fluid and the amount of fluid administered during surgery. The primary outcomes were defined as electrolyte imbalance and acidosis immediately after surgery. The secondary outcomes were the length of stay in the intensive care unit (ICU) and duration from the end of the operation to extubation.

RESULTS

A total of 586 patients were enrolled in this study, with each of 293 patients assigned to the NS and BC groups, respectively. Immediately after surgery, serum chloride levels were significantly higher in the NS group. Compared to the NS group, the BC group had lower incidence rates of acidemia (6.5% vs. 11.6%, p=0.043) and metabolic acidosis (0.7% vs. 4.4%, p=0.007). As compared to NS group, BC group had significantly shorter duration from the end of the operation to extubation (250±824 vs. 122±372 minutes, p=0.016) and length of stay in ICU (1.37±1.11 vs. 1.12±0.61 days, p=0.001). Throughout multivariable analysis, use of BC was found to be significant factor for favorable post-operative results.

CONCLUSION

This study showed that the patients who received BC during UIA clipping had lower incidence of metabolic acidosis, earlier extubation and shorter ICU stay compared to those who received NS. Therefore, using BC as a peri-operative fluid can be recommended for patients who undergo surgery for UIA.

Usefulness of Intraoperative Neurophysiological Monitoring During the Clipping of Unruptured Intracranial Aneurysm: Diagnostic Efficacy and Detailed Protocol

Background: Intraoperative neurophysiological monitoring (IONM) has been widely applied in brain vascular surgeries to reduce postoperative neurologic deficit (PND). This study aimed to investigate the effect of IONM during clipping of unruptured intracranial aneurysms (UIAs).

Methods: Between January 2013 and August 2020, we enrolled 193 patients with 202 UIAs in the N group (clipping without IONM) and 319 patients with 343 UIAs in the M group (clipping with IONM). Patients in the M group were intraoperatively monitored for motor evoked potentials (MEPs) and somatosensory evoked potentials (SSEPs). Irreversible evoked potential (EP) change was defined as EP deterioration that did not recover until surgery completion. Sustained PND was defined as neurological symptoms lasting for more than one postoperative month.

Results: Ten (3.1%) and 13 (6.7%) in the M and N groups, respectively, presented with PND. Compared with the N group, the M group had significantly lower occurrence rates of sustained PND [odds ratio (OR) = 0.36, 95% confidence interval (CI) = 0.13–0.98, p = 0.04], ischemic complications (OR = 0.39, 95% CI = 0.15–0.98, p = 0.04), and radiologic complications (OR = 0.40, 95% CI = 0.19–0.82, p = 0.01). Temporary clipping was an independent risk factor for ischemic complications (ICs) in the total patient group (OR = 6.18, 95% CI = 1.75–21.83, p = 0.005), but not in the M group (OR = 5.53, 95% CI = 0.76–41.92, p = 0.09). Regarding PND prediction, considering any EP changes (MEP and/or SSEP) showed the best diagnostic efficiency with a sensitivity of 0.900, specificity of 0.940, positive predictive value of 0.321, negative predictive value (NPV) of 0.997, and a negative likelihood ratio (LR) of 0.11.

Conclusion: IONM application during UIA clipping can reduce PND and radiological complications. The diagnostic effectiveness of IONM, specifically the NPV and LR negative values, was optimal upon consideration of changes in any EP modality.