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Mechanical stimulation of the trigeminal nerve during craniofacial, skull base, or dental surgeries may cause bradycardia, hypotension, or cardiac arrest. This phenomenon is called trigeminal cardiac reflex (TCR). We encountered a rare case of a patient who experienced sinus arrest due to temporary clipping of the intracranial carotid artery during the clipping of a ruptured aneurysm. We discuss possible reasons for the occurrence of TCR in this case. A man in his 30s with no medical history presented with a sudden-onset headache. Computed tomography revealed a subarachnoid hemorrhage in the basal cistern and left Sylvian fissure. Angiography revealed a saccular aneurysm of the left internal carotid-anterior choroidal artery. A left frontotemporal craniotomy and dural incision were performed, followed by a trans-Sylvian approach. Cardiac arrest occurred twice during the temporary clipping of the intracranial carotid artery. After surgery, we performed a cardiac ultrasound echo and a 1-week Holter electrocardiogram. Neither showed abnormalities. No arrhythmia or cardiac events were observed over a one and half-year follow-up period. The cardiac arrest might have been triggered by the stimulation of the trigeminal nerve in the internal carotid artery. The repeated and anatomical features of this case suggest that TCR triggered cardiac arrest. The high probability that cardiac arrest was induced by trigeminal nerve stimulation should be considered during the temporary clipping of the internal carotid artery. However, the predisposing factors and exact underlying mechanisms for these arrhythmias remain unknown and require further investigation. [ABSTRACT FROM AUTHOR]

Background: Neurosurgery's challenging area involves addressing intracranial aneurysms, given the high morbidity and mortality rates associated with them. Safe clipping, a technique that involves the intraoperative temporary occlusion of the arterial supply, is generally used. However, a focused review on the evolution of temporary clipping in intracranial aneurysms hasn't been previously carried out. Methods: We performed a comprehensive literature search on PubMed Medline and Google Scholar, using the combination of terms: [Temporary clip* AND (Cerebral OR Intracranial) Aneurysm]. Results: From an initial pool of 579 results, we excluded unrelated papers, narrowing it down to 25 relevant studies. These ranged from retrospective and prospective studies on the outcome favorability or radiological evidence, to analyses on potential independent prognostic factors, and articles related to the history and evolution of temporary clipping. Conclusion: Temporary arterial occlusion in aneurysm surgery has evolved significantly since its inception in the early 20th century, marked by innovations in instruments and temporary clips. Despite these advancements, the utility and safety of temporary clips continue to be topics of discussion, particularly due to concerns regarding possible complications and their influence on long-term results. [ABSTRACT FROM AUTHOR]

It is necessary to secure both the proximal and distal sides of the parent artery to prevent premature rupture when clipping cerebral aneurysms. Herein, we describe four cases in which the proximal internal carotid artery (ICA), affected by a paraclinoid aneurysm, was secured using an endoscopic endonasal approach. We used various tools, including a surgical video, cadaver dissection picture, artist's illustration, and intraoperative photographs, to elucidate the process. No patient experienced postoperative complications at our institution. Compared to the cervical or cavernous ICA, the ICA adjacent to the clivus (paraclival ICA) can be anatomically safely and easily exposed using an endoscopic endonasal approach because there is no need to consider cerebrospinal fluid leakage or hemorrhage from the cavernous sinus. Securing the proximal side of the parent artery using an endoscopic endonasal approach may be a viable method for clipping selected ICA aneurysms, such as paraclinoid aneurysms especially for upward or outward aneurysms of the C2 portion. [ABSTRACT FROM AUTHOR]

Intraoperative neurophysiological monitoring (IONM) represents one of the available technologies able to assess ischemia and aimed to improve surgical outcome reducing the treatment related morbidity in surgery for intracranial aneurysms. Many studies analyzing the impact of IONM are poised by the heterogeneity bias affecting the cohorts. We report our experience with IONM for surgery of unruptured middle cerebral artery (MCA) aneurysm in order to highlight its influence on functional and radiological outcome and surgical strategy. We retrospectively reviewed all MCA unruptured aneurysms treated between January 2013 and June 2021 by our institutional neurovascular team. Patients were divided into 2 groups according to the use of IONM. A total of 153 patients were included in the study, 52 operated on without IONM and 101 with IONM. The groups did not differ preoperatively regarding clinical status and aneurysm characteristics. Patients operated with IONM had better functional outcomes at discharge as well as at follow-up (p= 0.048, p=0.041) due to lower symptomatic ischemia and better radiological outcome due to lower rate of unexpected aneurysmal remnants (p= 0.0173). The introduction of IONM changed the use of temporary clipping (TeC), increasing its average duration (p= 0.01) improving the safety of dissecting and clipping the aneurysm. IONM in surgery for unruptured MCA aneurysm could improve the efficacy and safety of clipping strategy in the way it showed a role in changing the use of TeC and was associated to the reduction of unexpected aneurysmal remnants' rate and improvement in both short- and long-term patient's outcome. [ABSTRACT FROM AUTHOR]

Despite its widespread use, much is left to understand about the repercussions of parent artery temporary clipping in neurosurgery. This study seeks a better comprehension of the subject by aiming at the online measurement of brain tissue oxygen pressure (P bt O 2) during such events. This was a prospective observational study. Patients submitted to surgery for middle cerebral artery aneurysms (both ruptured and unruptured) were continuously monitored under Intensive Care Monitoring+ software, in order to obtain temporal (downstream) P bt O 2 levels while temporary clips were applied. Separate P bt O 2 curve events were identified, extracted, and processed. These were studied for assessing intraindividual and interindividual variability and the potential impact of repeated clipping and previous aneurysmal rupture. Eighty-six temporary clippings (from 20 patients) were recorded with a mean duration of 140.8 (41 − 238) seconds. Temporary arterial occlusion at the M1 segment of the middle cerebral artery produced specifically shaped trajectories, characterized by a preclipping P bt O 2 level, rapid downward sigmoid-shaped curve, succession of progressively angled slopes, and lower plateau. The steepest slope of the curve correlated strongly with P bt O 2 range (P < 0.001, r = 0.944). These features were highly reproducible only intraindividually and did not vary significantly with repeated clippings. The effects of temporary arterial occlusion on temporal lobe oxygenation demonstrate a high degree of singularity, highlighting the potential benefits of assessing individual available collateral circulation intraoperatively. The "P bt O 2 steepest slope" predicted the severity of P bt O 2 decrease and was available within the first minute. [ABSTRACT FROM AUTHOR]

Temporary clips are invaluable safety tools during the clipping of an aneurysm. Controversies regarding maximum permissible duration and safety, however, remain unanswered. This descriptive narrative attempts to review the literature to provide valuable insights on controversies clouding the use of temporary clips among neurosurgeons. Popular databases, including Pub Med, Medline/Medscape, Scopus, Cochrane, Embase, Google Scholar, were searched to find available literature on temporary clips. The searched MeSH terms were "Temporary Clip," "Temporary Clipping," "Cerebral Aneurysm," and "Aneurysm." Temporary clips have been in use since 1928 and have undergone considerable structural and technical modifications. A temporary clip's optimal safety limit is not yet defined with literature evidence ranging from immediate to 93 min. It is not yet definite whether temporary clips application aggravates vasospasm, but emergency temporary clips application, especially in poor-grade aneurysmal subarachnoid hemorrhage patients, is associated with poor outcomes. A temporary clip needs to be applied with caution in patients treated earlier by endovascular technique and having indwelling stents. Nitinol Stent is feasible, while a Cobalt-Chromium alloy stent does not get occluded and gets deformed under the closing pressure of a temporary clip. Although a temporary clip application is a fundamental strategy during the clipping of an aneurysm; the exact safe duration remains to be decided in randomized control trials. Their utility for the shorter duration is beneficial under un-conclusive evidence of neuroprotective agents and intraoperative monitoring. Neurosurgeons need to consider all aspects of their pros and cons for optimal use. [ABSTRACT FROM AUTHOR]

Context: The incidence of anterior communicating artery (Acomm) aneurysm is high and it is associated with high risk of rupture. Aims: The aim is to evaluate various factors (size, wall morphology, and fundus direction) associated with intraoperative rupture (IOR) of Acomm aneurysm. Settings and Design: Retrospective cohort study. Subjects and Methods: Our study includes 25 operated patients diagnosed to have ruptured Acomm aneurysm in the Department of Neurosurgery of Institute of Medical Sciences, Banaras Hindu University, Varanasi, India, between January 2016 and July 2020. Our study included all patients with ruptured Acomm aneurysm who received clipping as method of treatment. Statistical Analysis: Chi‑square test was used for analysis. Values with P < 0.05 were considered statistically significant. Statistical tests were done using GraphPad Prism version 8.3.0 software. Results: None of the patients with <4 mm, 6 patients of >4–10 mm, and 2 patients of >10 mm aneurysm size experienced IOR. IOR was seen in 2 patients with smooth wall and 6 in irregular aneurysm wall. All patients with posterior, 1 patient with inferior, 2 patients with anterior, and 1 patient with superior directing aneurysm experienced IOR. Patients with bilaterally clipped A1 experienced no IOR, while in unilaterally clipped aneurysm only 2 patients experienced IOR. Glasgow outcome score was better in patients with no IOR. Conclusion: The factors associated with high risk of IOR are: Aneurysm size >4 mm, multilobulated or irregular aneurysm wall, posteriorly and inferiorly directed aneurysms. Patients in whom Both A1 was temporarily clipped, experienced no IOR and better outcome. [ABSTRACT FROM AUTHOR]

To study clinical significance of augmentation of intraoperative motor evoked potentials (MEPs) during direct open surgery for middle cerebral artery (MCA) aneurysms. Between 2009 and 2017, 134 MCA aneurysm surgeries were performed with intraoperative MEP monitoring. The frequency and cause of augmentation with >50% increase of MEP amplitude from baseline were studied. Factors associated with MEP augmentation were investigated. MEP augmentation was demonstrated in 9 patients. All 9 events were observed just after application of the temporary clip to the parent artery. The ratio of the maximum amplitude to baseline was 2.6 ± 1.1 at an mean of 2.4 ± 1.1 minutes after parent artery occlusion. Ten patients who did not show MEP augmentation after parent artery occlusion were compared with the patients showing MEP augmentation. The distance of the temporary clip point from the midline was smaller in patients with MEP augmentation compared with patients without MEP augmentation (P = 0.033). MEP augmentation was thought to be an early ischemic sign preceding a significant decrease in MEPs during MCA aneurysm surgery. Transient augmentation of MEPs was more frequently observed in cases with a temporary clip applied to the more proximal part of the MCA. [ABSTRACT FROM AUTHOR]

Objective In direct aneurysm surgery, tentative clipping is frequently applied to facilitate aneurysm dissection. However, no systemic review on the pros and cons of tentative clipping has been conducted. This study aimed to investigate the efficacy and concerns of tentative clipping. Methods A total of 867 direct clippings in 737 patients were performed to treat intracranial aneurysms between 1994 and 2015. We retrospectively investigated the frequency, purpose, location, and adequacy of tentative clipping. Results Tentative clipping was performed in 149 of the 867 aneurysms that were clipped (17.2%). The purpose of tentative clipping was to dissect an aneurysm in 141 (94.6%), separate the vessels from the surface of a sac in 5 (3.4%), and prevent slipping of the final clip in 3 (2.0%) cases. Further dissection revealed that tentative clipping completely excluded the blood flow into the aneurysm in 126 (84.6%) of the 149 cases and incompletely shut it out in 23 (15.4%) cases. Five (21.7%) of the 23 patients with incomplete clipping had intraoperative aneurysm ruptures subsequently. Conclusions Tentative clipping facilitates dissection of the aneurysm sac from the surrounding structure but can occasionally lead to intraoperative rupture. Before applying tentative clips, surgeons should prepare for temporary clipping or additional tentative clipping in case of a rupture. Highlights • The pros and cons of tentative clipping are discussed. • Between 1994 and 2015, we performed 867 direct clippings in 737 patients to treat intracranial aneurysms. • Tentative clipping is a useful technique for dissecting aneurysms and preventing parent artery stenosis. [ABSTRACT FROM AUTHOR]

Objective : To propose a new measure for effective monitoring of intraoperative somatosensory evoked potentials (SEP) and to validate the feasibility of this measure for evoked potentials (EP) and single trials with a retrospective data analysis study. Methods : The proposed new measure (hereafter, a slope-measure) was defined as the relative slope of the amplitude and latency at each EP peak compared to the baseline value, which is sensitive to the change in the amplitude and latency simultaneously. We used the slope-measure for EP and single trials and compared the significant change detection time with that of the conventional peak-to-peak method. When applied to single trials, each single trial signal was processed with optimal filters before using the slope-measure. In this retrospective data analysis, 7 patients who underwent cerebral aneurysm clipping surgery for unruptured aneurysm middle cerebral artery (MCA) bifurcation were included. Results : We found that this simple slope-measure has a detection time that is as early or earlier than that of the conventional method; furthermore, using the slope-measure in optimally filtered single trials provides warning signs earlier than that of the conventional method during MCA clipping surgery. Conclusion : Our results have confirmed the feasibility of the slope-measure for intraoperative SEP monitoring. This is a novel study that provides a useful measure for either EP or single trials in intraoperative SEP monitoring. [ABSTRACT FROM AUTHOR]

Background – After surgery for ruptured anterior communicating artery (ACoA) aneurysm, several patients who have achieved a favorable neurological outcome yet have been observed to suffer from a poor cognitive outcome. The aim of this study was to explore the possible effects of temporary clip applications on frontal lobe functions in the patients with ruptured ACoA aneurysm. Methods – Forty patients were chosen among a series of cases who underwent an early surgery (within 96 h) after ACoA aneurysm bleeding. All of them were in Hunt–Hess grade 1 or grade 2. Of the 40 patients, temporary clipping was used in 22 patients (group A), whereas it was not used in 18 patients (group B). These two groups were compared with 20 volunteers (group C) without neurologic or psychiatric disorders. Results – The mean duration of temporary vessel occlusion for both A1 was 8.2 ± 2.9 min (4–15) in group A. Neither clinical nor radiographic strokes were detected. An improvement in frontal lobe function occurred at long term in group B patients. Whereas, cognitive deficits were persisting at long-term follow-up in group A, especially in patients who had temporary clipping duration longer than 9 min. Conclusions – The results emphasize that the negative effects of temporary vessel occlusion on cognitive changes occur before ischemic damage. Thus, such negative effects of temporary clipping on cognitive functions should not be neglected by surgeons during surgery. [ABSTRACT FROM AUTHOR]

This study investigated the neuroprotection provided by cytidine 5′-diphosphocholine (citicoline) during interrupted and uninterrupted occlusion of the basilar artery after subarachnoid hemorrhage (SAH) in 121 hypotensive rats. Animals were anesthetized and the basilar artery was exposed through a transclival approach. Baseline local cerebral blood flow (LCBF) values were recorded, and then the basilar artery was punctured, causing SAH. Blood was drawn to induce hypotension [60–70 mmHg mean arterial blood pressure (MABP)]. Control rats received intraperitoneal (i.p.) injections of 0.5 ml saline immediately after SAH before hypotension induction and after 60 min of occlusion. Experimental rats received 400-mg/kg citicoline i.p. at the same time points. Control group I and treatment group III were subjected to 60 min of interrupted occlusion (5 min of reperfusion after each 10 min of occlusion). Control group II and treatment group IV were subjected to 60 min of uninterrupted occlusion. MABP and LCBF were recorded every 5 minutes. Brain edema was evaluated in seven rats from each group at 24 hours after ischemic injury. At 3 days after occlusion, another set of 28 rats was killed and coronal brain slices were stained to assess infarct volume. The groups' physiological and edema findings were simi-lar. In all groups, LCBF fell immediately after SAH and remained below baseline throughout the experiment. In the citicoline-treated rats, arterial pressure increased significantly after 30–40 min of occlusion, and brain slices showed significantly smaller infarct volumes compared to control slices (p < 0.05). Mortality was significantly lower in the citicoline-treated animals (p < 0.001). The results suggest that citicoline provides significant neuroprotection during cerebral ischemia, and that it significantly reduces mortality. Part of the neuroprotective effect may be mediated by recovery of arterial pressure. [ABSTRACT FROM AUTHOR]

Most neurosurgeons consider temporary vessel occlusion for aneurysmal clipping an effective technique that facilitates dissection between the aneurysm and the parent vessel. It is generally believed that repeated short periods of cerebral ischemia are safer for the brain than a single long episode. The aim of this study was to identify whether interrupted and uninterrupted vessel occlusion differs with regard to changes in brain tissue and cerebral hemodynamics after subarachnoid hemorrhage (SAH). Fifty Spraque Dawley rats (300–350 g) were placed under general anaesthesia and ventilated. The basilar artery was exposed through a transclival approach. Baseline local cerebral blood flow (LCBF) values was measured, and then the basilar artery was punctured, causing subarachnoid hemorrhage (SAH). Group I (n = 24) was subjected to 60 min of interrupted basilar artery occlusion, defined as 5 min of reperfusion after every 10 min of occlusion, group II (n = 26) 60 min of uninterrupted artery occlusion. Three days after completion of the experiment, each rat was neurologically evaluated and decapitated. Coronal brain slices were obtained and stained to assess infarct volume. Immediately after SAH, LCBF fell by 58% in group I, and by 52% in group II. In group I, each ischemic insult brought a similar reduction in LCBF, and after each release of the occlusion there was a rapid rise in flow. In group II, the LCBF values dropped initially and remained at low levels until the end of the study. The 2, 3, 5 triphenyltetrazolium chloride stained sections showed similar volumes of brainstem infarction in both groups (38.3 ± 9.2 mm3 vs. 34.3 ± 8.7 mm3, respectively; p > 0.05). The results suggest that there is no neuroprotective advantage to either interrupted or uninterrupted temporary blockage of blood flow during neurovascular procedures after SAH in the basilar artery region. [ABSTRACT FROM AUTHOR]