Cerebral Aneurysm Surgery Research Articles

Temporary vessel occlusion in cerebral aneurysm surgery guided by direct cortical motor evoked potentials.

Temporary clipping is an important tool in the vascular neurosurgeon's armamentarium. We routinely utilize intraoperative neurophysiological monitoring (IONM) for complex brain aneurysm surgery cases, relying on direct cortical motor evoked potential (DCMEP) alerts to guide the duration of temporary clipping. Previous studies have argued for relatively short and intermittent temporary clipping strategies. In this study, we sought to assess the maximal permissive temporary clipping time during complex aneurysm surgery. To do this, we assessed patient outcome in relation to temporary clip duration guided by DCMEP. We queried our prospectively collected neuromonitoring database for anterior circulation aneurysm cases where temporary clipping was utilized by a single cerebrovascular surgeon between 2018 and 2021. Operative and IONM reports were reviewed. Patients in whom the duration of temporary clipping could not be determined were excluded. The operative strategy permissively allowed continuous temporary clipping as long as no neuromonitoring alerts were encountered. Maximal permissive parent artery occlusion time (Clipmax) was recorded as the longest duration of tolerated temporary vessel clipping without decrement in DCMEP. A total of 41 complex anterior circulation aneurysm clipping cases met criteria for this study. The mean Clipmax for all cases was just over 19min and did not differ between ruptured and unruptured aneurysms. Initial alert times were not found to be predictive of final permissive temporary clip duration after re-perfusion. In 100% (41/41) of cases, the aneurysm was completely clip occluded without residual on catheter angiogram. Stable or improved modified Rankin Score was achieved in 98% (40/41) of cases at 3-month follow-up. This study demonstrates that using DCMEP can facilitate relatively long but safe temporary clipping durations in complex anterior circulation aneurysm surgery. In the endovascular era with only a limited subset of technically challenging aneurysms needing open surgical treatment, extended permissive temporary clipping guided by DCMEPs can significantly enhance a surgeon's ability to achieve excellent technical and clinical outcomes.

Commentary: The Importance of the Temporary Clip Removal Phase on Exposure to Hypoxia: On-Line Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms.

Wipplinger, Christoph MD*; Wipplinger, Tamara M. MSc‡; Griessenauer, Christoph J. MD§,‖ Author Information

Commentary: The Importance of the Temporary Clip Removal Phase on Exposure to Hypoxia: On-Line Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms.

*Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA; ‡Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA Correspondence: Daniel M. S. Raper, MBBS, Department of Neurosurgery, Baylor College of Medicine, 7200 Cambridge St, Suite 9B, Houston, TX 77030, USA. Email: [email protected]

The Importance of the Temporary Clip Removal Phase on Exposure to Hypoxia: On-Line Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms.

Most studies concerning intraoperative temporary arterial occlusion overlook the period between and after clip placement. To analyze the brain tissue oxygen tension through the process by which anterograde arterial blood flow is re-established after temporary clipping (TR). In this prospective observational study, patients who presented to surgery for middle cerebral artery aneurysms were continuously monitored with ICM+, to obtain temporal (downstream) PbtO2 levels while M1 segment temporary clips were applied and removed. PbtO2 changes were analyzed and compared with the clipping phase, and measures of exposure to hypoxia were defined and assessed during both phases and used in a model to test the impact of extending them. Eighty-six TRs (20 patients) were recorded. The mean acquired amount of time per clip release (CR) event was 336.7 seconds. Temporary clip removal produced specifically shaped, highly individual PbtO2 curves that correlated with their corresponding clipping phase events but developing slower and less consistently. The CR phase was responsible for greater cumulative exposure to hypoxia than the clip application phase through the first and second minutes of each. In our model, the duration of the TR phase was mostly responsible for the total exposure to hypoxia, and longer CR phases reduced the mean exposure to hypoxia. During the clip removal phase, the brain tissue is still exposed to oxygen levels that are significantly below the baseline, reverting through a singular, dynamic process. Therefore, it must be regarded by surgeons with the same degree of attention as its counterpart.

Burr Hole Microsurgery for Middle Cerebral Artery Aneurysms: A Clinical Case Series

BACKGROUND: Minimally invasive microsurgery has become popular in neurosurgery. Burr hole microsurgery is another more modern minimally invasive technique that allows surgical treatment of various intracranial pathologies through an extreme small craniotomy. This article presents the first application of the burr hole approach for microsurgical clipping of cerebral aneurysms. OBJECTIVE: To assess the feasibility and outcomes of using the burr hole microsurgical technique in cerebral aneurysm surgery. METHODS: From March 2020 to August 2020, 3 patients with unruptured middle cerebral artery aneurysms underwent burr hole microsurgical clipping. RESULTS: Three patients with middle cerebral bifurcation aneurysms were successfully treated. The duration of surgery was from 62 to 83 min (median 72.5). Postoperatively, no new neurological symptoms, complications, or mortality were observed in all the cases. CONCLUSION: Burr hole microsurgery is an advanced neurosurgical method. Although the surgery is performed through a small burr hole approximately 14 mm in size, safe and successful treatment of normal-sized middle cerebral artery aneurysms using standard microsurgical principles and technique is possible.

Surgery for multiple cerebral aneurysms: Literature review and case report

We report a case of simultaneous microsurgical clipping of 5 cerebral aneurysms in a patient with multiple aneurysms of the anterior brain.We analyzed the existing treatment approaches to multiple cerebral aneurysms, including endovascular isolation, microsurgical clipping, as well as surgical tactics in case of subarachnoid hemorrhage. We covered the recommendations for screening, surgical risks, and approaches to aneurysm isolation (single-stage and multiple-stage).Using our own experience (since no strict guidelines are currently available), we concluded that it is important to screen cerebral vessels of all close relatives of patients with multiple and familial cerebral aneurysms.

Usability and Advantages of a “Flat Tip” Bayonet-type Micro Forceps in Tissue Dissection during Cerebral Aneurysm Surgery

Usability and Advantages of a “Flat Tip” Bayonet-type Micro Forceps in Tissue Dissection during Cerebral Aneurysm Surgery

Responsibilities during Open Surgery for Cerebral Aneurysms

脳動脈瘤の開頭手術はすでに成熟した状態にある. 大型巨大瘤もバイパス技術があれば対応可能であるし, 傍鞍部においても頭蓋底技術で確実な処置ができる. 血管内治療の適応範囲がデバイスの発展によって広がっている現在, 侵襲的な開頭術が担うべき責務は, 安全性と根治性にある. 単純なクリッピングもclosure lineの追及が求められるし, バイパスもあらゆる場所に対して遂行できる技術が必要である. 前床突起削除, 錐体骨削除, 後頭顆削除も着実に身に着けておく必要がある.

Efficacy of Intraoperative Blood Salvage in Cerebral Aneurysm Surgery.

Background. The use and effectiveness of intraoperative cell salvage has been analyzed in many surgical specialties. Until now, no data exist evaluating the efficacy of intraoperative cell salvage in cerebral aneurysm surgery. Aim. To evaluate the efficacy and cost effectiveness of intraoperative cell salvage in cerebral aneurysm surgery. Methods. Data were collected retrospectively for all the patients who underwent cerebral aneurysm surgery at our institution between 2013 and 2019. Routinely, we apply blood salvage through autotransfusion. The cases were divided into a ruptured cerebral aneurysm group and a unruptured cerebral aneurysm group. Results. A total of 241 patients underwent cerebral aneurysm clipping. Of all the cerebral aneurysms, 116 were ruptured and 125 were unruptured and clipped electively. Age, location of the aneurysm, postoperative red blood cell count, intraoperative blood loss, and number of allogenic blood cell transfusions were statistically significantly different between the groups. The autotransfusion of salvaged blood could only be facilitated in eight cases with ruptured cerebral aneurysms and in none with unruptured cerebral aneurysms clipped electively (p < 0.01). Additionally, 35 patients with ruptured cerebral aneurysms and one patient with unruptured cerebral aneurysm required allogenic red blood cell transfusion after surgery, and 71 vs. 2 units of blood were transfused (p < 0.0001). In terms of cost effectiveness, a total of EUR 45,189 in 241 patients was spent to run the autotransfusion system, while EUR 13,797 was spent for allogenic blood transfusion. Conclusions. The use of cell salvage in patients with unruptured cerebral aneurysm, undergoing elective surgery, is not effective.

Assessing the development status of intraoperative fluorescence imaging for perfusion assessments, using the IDEAL framework

ObjectivesIntraoperative fluorescence imaging is currently used in a variety of surgical fields for four main purposes: assessing tissue perfusion; identifying/localizing cancer; mapping lymphatic systems; and visualizing anatomy. To establish evidence-based...

Single-Institute Experience of Bypass Surgery for Complex Anterior Cerebral Artery Aneurysms: Paying Special Attention to the Spatial and Diameter Relationship Between the Efferent Arteries

To present a retrospective review of a single-institute experience with bypass surgery of complex anterior cerebral artery aneurysm. Eight patients (5 females and 3 males; mean age, 34.2 years) with complex anterior cerebral artery aneurysms were treated with bypass. There were 3 precommunicating aneurysms, 1 communicating artery aneurysm, and 4 postcommunicating aneurysms (2 in A2 and 2 in A3). A3-A3 side-to-side in situ bypass was performed in 6 cases. A3-radial artery-A3 interpositional bypass was performed in 1 case with A3 segments located far apart, and A3-A3 transplantation was performed in 1 case with nonparallel aligned A3 segments. Of the 8 aneurysms, 3 were secured with proximal clipping, 1 was secured with distal clipping, 1 was secured with direct clipping, 1 was secured with isolation, and 2 were secured with embolization. Aneurysm obliteration was achieved in all cases. Only 1 in situ bypass from a smaller donor artery to a larger recipient artery failed with minor postoperative infarction. Intraoperative bleeding from the site of anastomosis occurred in 1 case during embolization. All patients had complete recovery with normal neurological function during follow-up at outpatient clinics. We established a simplified surgical algorithm for complex anterior cerebral artery aneurysms based on the geometrical and spatial relationship between efferent arteries. The reasons for bypass failure and hemorrhagic complication were also discussed.

The Effects of Temporary Clipping as an Expression of Circulatory Individuality: Online Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms

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 (PbtO2) 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) PbtO2 levels while temporary clips were applied. Separate PbtO2 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 PbtO2 level, rapid downward sigmoid-shaped curve, succession of progressively angled slopes, and lower plateau. The steepest slope of the curve correlated strongly with PbtO2 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 "PbtO2 steepest slope" predicted the severity of PbtO2 decrease and was available within the first minute.

Microsurgical Management of the Middle Cerebral Artery Bifurcation Aneurysms: An Anatomic Feasibility Study

Background: The proper head positioning decreases the surgical complications by enabling a better surgical maneuverability. Middle cerebral artery (MCA) bifurcation aneurysms have been classified by Dashti et al. [Surg Neurol. 2007 May;67(5):441–56] as the intertruncal, inferior, lateral, insular, and complex types based on dome projection. Our aim was to identify the optimum head positions and to explain the anatomic variables, which may affect the surgical strategy of MCA bifurcation aneurysms. Methods: The lateral supraorbital approach bilaterally was performed in the 4 cadaveric heads. All steps of the dissection were recorded using digital camera. Results: The distal Sylvian fissure (SF) dissection may be preferred for insular type and the proximal SF dissection may be preferred for all other types. Fifteen degrees head rotation was found as the most suitable position for the intertruncal, lateral type and subtype of complex aneurysms related with superior trunk. Thirty degrees head rotation was found the most suitable position for the inferior type, insular type, and subtype of complex aneurysms related with inferior trunk. Conclusions: The head positioning in middle cerebral bifurcation aneurysms surgery is a critical step. It should be tailored according to the projection and its relationship with the parent vessels of the middle cerebral bifurcation.

Impact of acetylsalicylic acid in patients undergoing cerebral aneurysm surgery \u2013 should the neurosurgeon really worry about it?

There has been an increase in the use of acetylsalicylic acid (ASA, Aspirin®) among patients with stroke and heart disease as well as in aging populations as a means of primary prevention. The potentially life-threatening consequences of a postoperative hemorrhagic complication after neurosurgical operative procedures are well known. In the present study, we evaluate the risk of continued ASA use as it relates to postoperative hemorrhage and cardiopulmonary complications in patients undergoing cerebral aneurysm surgery. We retrospectively analyzed 200 consecutive clipping procedures performed between 2008 and 2018. Two different statistical models were applied. The first model consisted of two groups: (1) group with No ASA impact - patients who either did not use ASA at all as well as those who had stopped their use of the ASA medication in time (> = 7 days prior to operation); (2) group with ASA impact - all patients whose ASA use was not stopped in time. The second model consisted of three groups: (1) No ASA use; (2) Stopped ASA use (> = 7 days prior to operation); (3) Continued ASA use (did not stop or did not stop in time, <7 days prior to operation). Data collection included demographic information, surgical parameters, aneurysm characteristics, and all hemorrhagic/thromboembolic complications. A postoperative hemorrhage was defined as relevant if a consecutive operation for hematoma removal was necessary. An ASA effect has been assumed in 32 out of 200 performed operations. A postoperative hemorrhage occurred in one out these 32 patients (3.1%). A postoperative hemorrhage in patients without ASA impact was detected and treated in 5 out of 168 patients (3.0%). The difference was statistically not significant in either model (ASA impact group vs. No ASA impact group: OR = 1.0516 [0.1187; 9.3132], p = 1.000; RR = 1.0015 [0.9360; 1.0716]). Cardiopulmonary complications were significantly more frequent in the group with ASA impact than in the group without ASA impact (p = 0.030). In this study continued ASA use was not associated with an increased risk of a postoperative hemorrhage. However, cardiopulmonary complications were significantly more frequent in the ASA impact group than in the No ASA impact group. Thus, ASA might relatively safely be continued in patients with increased cardiovascular risk and cases of emergency cerebrovascular surgery.

What Is the Key Point for Intraoperative Monitoring in Cerebral Aneurysm Surgery?

Intraoperative monitoring, which has advanced in the 21st century, consists of the motor evoked potential(MEP)and visual evoked potential(VEP). Transcranial stimulation has become the mainstream of MEP from cortical stimulation, and reports of MEP monitoring for the face and lower limbs are increasing. The biggest problem with VEP is poor reproducibility due to inhalation anesthetics. With the increase use of of MEP, total intravenous anesthesia has become common and reproducibility has improved, making it a clinically useful method. I will mention the key points of current intraoperative monitoring in cerebral aneurysm surgery. 1. Selection of type of intraoperative monitoring: Is MEP cortical stimulation or transcranial stimulation, upper limb or lower limb? What is VEP? What is somatosensory evoked potential? 2. What to do when the waveform deteriorates or disappears? Remove the clip after clipping. If the blood flow is temporarily occluded, release the occlusion as soon as possible. When the deterioration improves after this maneuver, it should be stopped until the waveform is restored. 3. Pitfall and coping method: Anesthesia method. Changes in the stimulation threshold of the transcranial stimulation MEPs. Deterioration/disappearance of MEP waveform after release of brain traction.

An Evaluation of the Safety and Feasibility of Adenosine-assisted Clipping Surgery for Unruptured Cerebral Aneurysms: Study Protocol.

The effectiveness of adenosine-induced flow arrest in surgical clipping for the cerebral aneurysms with difficulties in temporary clip placement to the proximal main trunk has been reported. This is the first clinical trial to evaluate the safety and feasibility of adenosine-assisted clipping surgery for unruptured cerebral aneurysms (UCAs) in Japan. The inclusion criteria are as follows: patients over 20 years old, patients who agree to be enrolled in this study after providing informed consent, patients who undergo clipping surgery for UCA in our institute, and patients in whom the surgeons (T.H. or I.D.) judge that decompression of the aneurysm is effective. The primary endpoint is a modified Rankin Scale (mRS) score 30 days after surgery. We plan to enroll 10 patients in this study. The original protocol of adenosine administration was established in this trial. Herein, we present the study protocol.

Combined Bypass and Cerebral Aneurysm Surgery:How to Choose and Practice?

The treatment for cerebral aneurysms has been changing along with the advancements in endovascular treatment. In particular, the induction of a flow-diverter stent can treat even cavernous portion aneurysms, which have been difficult to treat without parent artery occlusion. The definite advantages of the open surgery are low recurrence rates, high angiographic outcome, and bypass. Herein, we describe the bypass method for treating cerebral aneurysms. The purpose of the bypass, difference between high-flow and low-flow bypasses, how to select the donor artery, and variation of bypass technique are described.

Important Points for Patient Positioning and Head Fixation in Cerebral Aneurysm Surgery

Patient positioning and head fixation are two of the most important aspects of cerebral aneurysm surgery. These procedures require an accurate understanding of the anatomy of the scalp and skull and of the process for approaching aneurysms. We describe the basics of this procedure in frontotemporal craniotomy, which is most frequently used in cerebral aneurysm surgery, with a focus on head fixation using the MAYFIELD three-pin skull clamp(Integra LifeSciences). The insertion sites of the head pins should be avoided in areas with thin bone, such as the frontal sinus and temporal squama, and just above the arteries of the scalp and venous sinuses. The position of the head should be determined based on three factors: rotation, vertex up or down, and tilt. The head should be elevated to reduce intracranial pressure, and cervical hyperflexion should be avoided to prevent increased venous pressure.

Use of Aquarius NET® to Plot Coordinates for Direct Surgery of Middle Cerebral Artery Aneurysms

Use of Aquarius NET® to Plot Coordinates for Direct Surgery of Middle Cerebral Artery Aneurysms

A Morphological Study of Anatomical Variations in 96 Circles of Willis: an Autopsic Evaluation and Literature Review

Aim and background: Because circle of Willis provides the best collateral source of blood flow in arterial occlusive disorders, identifying anatomical variants that could be present at this level is especially essential in planning surgery for cerebral aneurysms. Given the fact that the frequency of these anatomical variations of circle of Willis has not yet been sufficiently evaluated in the Romanian population until presently, we have conducted a research in a regional health unit, where there are admitted patients with neurological and neurosurgical diseases living in the North-Eastern region of Romania, in order to identify morphological features of the constituent vessels of fresh circles of Willis at the moment of the autopsy of the deceased patients in the Emergency Clinical Hospital „Prof. dr. N. Oblu” Ia�?i. There has been noted the presence or absence, variations of shape, position or trajectory of each arterial segment. In the end, our results were compared with those from literature in order to identify some particular pattern of this anastomotic structure in the population of the North-Eastern region of Romania. Materials and Methods: The present research is a descriptive in-hospital observational study on the morphology of the circles of Willis of 96 patients who died of various medical causes in the Emergency Clinical Hospital “Prof. dr. N. Oblu” Ia�?i, in a period of 30 months, to whom an anatomo-clinical autopsy was performed in order to determine the cause of death. Results: From the total of 96 available human brains, 28 cases (29.17%) were classified as ”atypical” as they expressed anatomical variants of the constituent vessels. Among the 28 deceased patients with atypical CW, the M: F ratio was 1.15 and the average age of the entire group was 61.78 years. From the 28 atypical circles of Willis, 19 of them (67.86%) presented multiple anatomical variants, and only 9 cases (32.14%) had a single anatomical variant. Among multiple variants of the vessels of the circle of Willis, we identified the association of two (32.14%), three (25%), four (7.14%), or five (3.57%) anatomical variants of those seven constituent arteries. Eight types of variations of the constituent arteries of the circle of Willis were identified: absence of a vessel, partial fetal ACP, hypoplasia, duplication, fenestration, azygos, common trunk with another vessel at the origin, longer length with sinuous trajectory. Conclusion: Our results showed intermediate values between those reported in various studies performed on circles of Willis obtained at autopsies. These differences can be interpreted as possible peculiarities of the population in North-Eastern region of Romania. Unlike all other studies with which we compared the results obtained, in our research two thirds of cases with variations presented multiple anatomical variants, including five simultaneous variants.