Efficacy of Endovascular Treatment for Distal Anterior Cerebral Artery Aneurysms: A Multicenter Observational Study.

OBJECTIVES: Distal anterior cerebral artery (DACA) aneurysms account for 1%-9% of all intracranial aneurysms. Microsurgical treatment is generally preferred for DACA aneurysms; however, it presents challenges owing to the anatomical complexities. Advances in neuro-interventional techniques have yielded promising results. This study aims to compare the clinical outcomes of DACA aneurysms treated with microsurgery and endovascular treatment (EVT) to elucidate the efficacy of EVT. MATERIALS AND METHODS: A multicenter observational registry comprising 16 stroke centers was utilized for this study. Data was retrospectively and prospectively analyzed from 166 patients with DACA aneurysms in our database, which included 4,552 consecutive patients with ruptured or unruptured intracranial aneurysms who underwent microsurgical or endovascular treatment between January 2013 and December 2021. RESULTS: Surgical clipping was performed in 115 patients, and 51 underwent coil embolization. The median follow-up duration was 15.3 months. No significant differences were observed in patient characteristics between the two treatment modalities. There were no differences in complication-related morbidity between the microsurgical treatment and EVT groups in either unruptured (10.5% vs. 9.1%, p=1.00) or ruptured aneurysms (5.2% vs. 6.9%, p=0.66). Coil embolization resulted in higher recurrence and retreatment rates than surgical clipping did, especially for ruptured aneurysms (2.6% vs. 27.6%, p<0.01). CONCLUSIONS: Endovascular treatment is an alternative to microsurgery for DACA aneurysms especially in unruptured cases or the patients who have difficulty undergoing craniotomy due to their general condition, albeit with considerations for higher recurrence and retreatment rates, particularly in ruptured cases. Close follow-up is crucial for the effective management of these challenges. Further studies are needed to refine the treatment strategies for DACA aneurysms.

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

OBJECTIVE: Trans-eyebrow supraorbital aneurysmal neck clipping, also known as keyhole surgery, have many advantages of minimal invasive surgery. However, there are few studies on whether there is a difference in keyhole surgery according to the location of the aneurysm, and how the complications after keyhole approach differ from the conventional approach. The authors investigated the surgical outcome of keyhole aneurysmal surgery for clarify the characteristics of keyhole surgery. METHODS: A retrospective study was performed with review of medical records and images of patients with anterior circulation aneurysm undergoing aneurysmal clipping with keyhole surgery. The patient's clinical condition, imaging, surgical condition, and outcome were investigated. RESULTS: As a result of analysis about the location of the aneurysm, middle cerebral artery (MCA) aneurysm group had a longer operation time than internal carotid artery and anterior cerebral artery aneurysm groups, but there was no significant difference in complication rate. The olfactory dysfunction occurred more than that of conventional surgery and occurred less in MCA aneurysm group than others. Scalp sensory change in the surgical site was more common in patients with unruptured aneurysms. CONCLUSION: By accurately investigating the frequency and severity of complications associated with trans-eyebrow aneurysmal neck clipping surgery, it can help to select a surgical approach considering risk versus benefit. In addition, patient's satisfaction can be increased by providing information to patients and caregivers in advance about the outcome of this approach and the anticipated complications.

Superficial Temporal Artery to Anterior Cerebral Artery Hemi-bonnet Bypass Using Radial Artery Graft for Prevention of Complications after Surgical Treatment of Partially Thrombosed Large/Giant Anterior Cerebral Artery Aneurysm.

BACKGROUND: Partially thrombosed large/giant aneurysm of the anterior cerebral artery is still challenging because this complex aneurysm requires arterial revascularization in the deep operation field. Therefore, direct neck clipping is often impossible. We describe our experiences with extracranial-intracranial bypass as an insurance bypass prior to clipping of partially thrombosed anterior cerebral artery aneurysms, and discuss the microsurgical technique and strategy. CLINICAL PRESENTATION: Consecutive, single-surgeon experience with the surgical treatment of partially thrombosed anterior cerebral artery aneurysms was retrospectively reviewed. Three cases of partially thrombosed anterior cerebral artery aneurysms, 2 anterior communicating artery aneurysms, and 1 postcommunicating artery (A2 segment of the anterior cerebral artery) aneurysm, presented as mass effect symptoms from giant aneurysms in 2 patients and incidentally discovered aneurysm in one patient. Superficial temporal artery-radial artery graft-anterior cerebral artery hemi-bonnet bypass was performed as an insurance bypass prior to clipping of the partially thrombosed anterior cerebral artery aneurysms. Complete aneurysm obliteration and bypass patency were demonstrated in all 3 patients. No neurological sequelae occurred. CONCLUSIONS: Superficial temporal artery-radial artery graft-anterior cerebral artery hemi-bonnet bypass prior to aneurysm dissection can avoid ischemic complication during temporary occlusion and secures permanent revascularization after complete obliteration of partially thrombosed large/giant anterior cerebral artery aneurysm.

Assessment of morphology and hemodynamics in a surgically clipped neck of a cerebral aneurysm: illustrative case.

BACKGROUND: Silent magnetic resonance angiography reduces metal artifacts, enabling clear visualization of the clipped neck following surgical clipping of cerebral aneurysms. This study aimed to delineate the morphology of the clipped neck complex in cerebral aneurysms using three-dimensional (3D) multifusion imaging of silent magnetic resonance angiography and fast spin echo magnetic resonance cisternography. Additionally, computational fluid dynamics analysis was utilized to evaluate the hemodynamics of the parent vessel at the clipped neck, allowing for a detailed assessment of hemodynamics at the clipped neck. OBSERVATIONS: The 3D multifusion image enabled visualization of the orientation and shape of the clip within the clipped neck complex, alongside the morphology of the parent vessel. In the hemodynamic analysis of the parent vessel at the clipped neck, areas of high-intensity magnitude of wall shear stress (WSSm) variation corresponding to the clip's contour, along with significant vector of wall shear stress (WSSv) variation related to vector directionality, were visualized in 3D. The intentional residual neck, coated with muscle grafts, was depicted as an area with low WSSm variation values and high WSSv variation values. LESSONS: Three-dimensional multifusion imaging, along with computational fluid dynamics analysis of the parent vessels, facilitated both the morphological and hemodynamic visualization and assessment of the clipped neck complex following neck clipping surgery for cerebral aneurysms. https://thejns.org/doi/10.3171/CASE24194.

Multiscope Technique Combining an Endoscope and Exoscope for Neck Clipping of Cerebral Aneurysms.

OBJECTIVE: In aneurysm clipping, the use of an endoscope improves the visualization of the anatomic structures around the aneurysm, allowing for improved dissection and clipping techniques. Furthermore, it makes the surgery less invasive. The disadvantage of using the endoscope and microscope together is that the surgeon must move the line of sight significantly between viewing the operative field through the eyepiece of the microscope and viewing the endoscope monitor. This disadvantage makes it difficult for the surgeon to safely insert the endoscope in the optimal position. This study presents a new method for observing the surgical field with a picture-in-picture system using both an endoscope and an exoscope that can overcome the disadvantage of multiscope surgery. METHODS: The endoscope was used when the anatomic structures around the aneurysm could not be observed with the exoscope only. An image from the endoscopic monitor was inserted into the exoscopic monitor. The surgeon inserted the endoscope in the optimal position while viewing the endoscope monitor and ensured that the structures in the path of the endoscope were not damaged while they viewed the exoscope monitor. RESULTS: Three patients underwent aneurysm clipping. The use of an endoscope made the procedure less invasive, and the surgeon was able to safely insert the endoscope in the optimal position. Only slight movement of the line of sight was required to view the 2 monitors. CONCLUSIONS: The endoscope and exoscope multiscope picture-in-picture system can facilitate safer aneurysm clipping compared with combined microscopic and endoscopic surgery.

Usefulness of Orbitocranial Approach in Neck Clipping of Aneurysms Arising from Middle Cerebral Artery Proximal to the Limen Insulae: A Case Series.

BACKGROUND: Neck clipping of the aneurysms arising from the middle cerebral artery (MCA) proximal to the limen insulae is often difficult because of difficulties in securing a bright and wide operative field to observe the aneurysms and surrounding structures, such as the anterior perforated substance, lenticulostriate arteries, and early frontal branch. Our objective was to determine the usefulness of the orbitocranial approach in neck clipping of the aneurysms arising from the MCA proximal to the limen insulae. METHODS: This prospective study included 7 patients who underwent neck clipping of aneurysms arising from the MCA proximal to the limen insulae through the orbitocranial approach. In addition to conventional pterional craniotomy, the superiolateral orbital rim was resected with a 1-piece fashion. Its procedures, complications, and outcomes were reviewed. RESULTS: Removal of the superolateral orbital rim facilitated a bright and wide observation from the skull base side. It was much easier to identify the anterior perforated substance, lenticulostriate arteries, and early frontal branch around the aneurysm through the orbitocranial approach than through the conventional pterional approach. Neck clipping could be performed completely and safely in all cases. CONCLUSIONS: The orbitocranial approach to aneurysms arising from the MCA proximal to the limen insulae provides us a bright and wide operative field compared with the conventional pterional approach, which is useful to secure complete and safe neck clipping by avoiding cerebral contusion and unexpected obstruction of the early frontal branch.

Incidental Microaneurysms During Microvascular Surgery: Incidence, Treatment, and Significance.

BACKGROUND: Although new imaging tools have been developed for the detection of smaller aneurysms, angiographically negative microaneurysms are still encountered during cerebral microsurgery. Currently, only limited information regarding incidence and efficacy of treatment of these microaneurysms is available. METHODS: We investigated the incidence and treatment of incidental microaneurysms (IMAs) in the last 5 years. IMAs are unidentifiable and invisible on preoperative angiography, but are detected during microvascular surgery. The inclusion criteria were aneurysm cases treated with microsurgery via transsylvian approaches, and those undergoing preoperative digital subtraction angiography. RESULTS: This study enrolled 484 surgical cases (248 cases of subarachnoid hemorrhage and 236 cases of unruptured aneurysms) in 460 patients, and 33 tiny aneurysms were found in 31 operative cases (6.4% incidence per operation). The most typical type was located on another branching site of the middle cerebral artery found during neck clipping of the middle cerebral artery bifurcation aneurysm. A patient with multiple aneurysms presented a statistically significant risk (375/78 vs. 15/16; P < 0.001) of IMA identification. IMAs were treated by clipping and wrapping in 18 and 15 cases, respectively, without complications. CONCLUSIONS: This study revealed a 6.4% incidence of IMAs; however, this could be underestimated because of the limited range of inspection. Early detection of an IMA through careful inspection during microvascular surgery could be beneficial, especially in patients with multiple aneurysms.

Microsurgical Clipping of Basilar Apex Aneurysms: A Systematic Historical Review of Approaches and their Results.

OBJECTIVE: Neck clipping remains a valuable treatment option for basilar apex aneurysms, especially in those with complex morphology, such as incorporation of branching vessels or large size, and young patient age. Several approaches have proved to give effective exposure for various types of lesion morphologies. Our historic literature review from 1976 to the present systematically compares the outcomes and complications of the key surgical approaches in the treatment of basilar apex aneurysms. METHODS: We searched PubMed for articles with at least 5 patients, data on neurologic outcome, and procedure-associated complications for the following approaches: pterional or orbitozygomatic transsylvian, subtemporal (with or without zygomatic osteotomy), pretemporal (with or without transcavernous extension), and transpetrous. n-Weighted averages for clinical outcome, aneurysm occlusion rates, morbidity, mortality, and aneurysm morphology were compared. RESULTS: Of 35 articles selected, 2041 patients with 722 ruptured aneurysms underwent microsurgery, including 1131 transsylvian, 241 pretemporal, 375 subtemporal, and 17 transpetrous approaches. Comparing these 4 approaches in n-weighted averages, respectively, we noted good neurologic outcomes (81%, 85%, 81%, and 58%), surgical morbidity (14%, 10%, 34%, and 53%), surgical mortality (4%, 1%, 0, and 1%), and complete occlusion rates (95%, 94%, 86%, and 75%). CONCLUSIONS: Transsylvian, pretemporal, and subtemporal approaches showed favorable neurologic outcomes at similar rates and were applied for aneurysms located between -1mm and +7mm in relation to the posterior clinoid process. The pretemporal approach was preferably applied to large and giant aneurysms with good outcome; the transsylvian approach was most frequently used for ruptured aneurysms.

A case of unruptured aneurysm of the internal carotid artery presenting as olfactory hallucinations.

BACKGROUND: Olfactory hallucination, a symptom of medial temporal lobe epilepsy, is rarely associated with unruptured intracranial aneurysms. CASE DESCRIPTION: We encountered this situation in a 70-year-old woman with an unruptured aneurysm at the bifurcation of the internal carotid and posterior communicating artery. We were able to achieve epileptic control by craniotomy clipping and medial temporal lesionectomy. CONCLUSION: According to our knowledge, previous reports are limited to cases of large middle cerebral artery aneurysms compressing the lateral orbitofrontal cortex, and this is apparently the first report of a case where olfactory hallucinations occurred from direct stimulation of the entorhinal cortex by an internal carotid and posterior communicating artery bifurcation aneurysm. We examined the pathophysiology underlying the development of olfactory hallucinations. We found craniotomy clipping and focal resection to be useful from the standpoint of seizure control. Whether seizure control can also be obtained with intracranial aneurysm coiling should be investigated in the future.

A technique for sequential, progressive clipping for a giant thrombosed distal anterior cerebral artery aneurysm: Technical note.

BACKGROUND: Giant thrombosed aneurysms often present with thickened walls and a hard thrombus, including in the near-neck aneurysmal sac. These usually make it difficult to achieve complete neck clipping with preservation of local branch patency. Here, we demonstrate a simple but safe and effective technique to overcome these problems in a patient with a 6-cm giant thrombosed distal anterior cerebral artery aneurysm. CASE DESCRIPTION: A 77-year-old-man suffered from loss of volitional activity due to the frontal mass effect. The aneurysm was exposed with unilateral paramedian craniotomy and an interhemispheric approach. The clip was applied to the aneurysmal neck but it slipped onto the parent artery, which caused branch artery occlusion. Intra-aneurysmal thrombectomy was immediately performed near the aneurysmal neck with ultrasonic aspiration. The next clip was added along the aneurysm side of the preceding clip, which was then removed. This procedure was repeated twice so that complete neck clipping was achieved while preserving the branch patency. All the residual thrombus and aneurysmal wall were subsequently removed. Postoperatively, there was no additional neurological deficit. The patient's mental function was significantly improved. CONCLUSIONS: We conclude that the sequential, progressive clipping technique is a robust option for successful neck clipping of giant thrombosed aneurysms.

Spontaneous Regression of Aneurysm Remnant after Incomplete Surgical Clipping in a Patient with Ruptured Cerebral Aneurysm.

Cases of spontaneous regression of cerebral aneurysm remnant after incomplete surgical clipping have been rarely reported. This paper reports the regression of an aneurysm remnant after incomplete surgical clipping during postsurgical follow-up. A 50-year-old male presented with subarachnoid hemorrhage because of rupture of an anterior communicating artery aneurysm. An emergency clipping of the aneurysm was performed. A cerebral angiography, which was performed two weeks postoperatively, revealed an aneurysm remnant. The patient refused additional treatment and was discharged without apparent neurological deficit. One-year follow up cerebral angiography demonstrated a partially regressed aneurysm remnant.

Risk Factors for Visual Impairments in Patients with Unruptured Intradural Paraclinoid Aneurysms Treated by Neck Clipping without Bypass Surgery.

OBJECTIVE: Although paraclinoid aneurysms are now frequently referred for endovascular treatment, the durability of obliteration is still to be determined. Therefore, direct surgery for paraclinoid aneurysms still remains indispensable. The present study aimed to evaluate the risk factors for the visual impairments in patients with unruptured intradural paraclinoid aneurysms. METHODS: The data of 133 patients with 136 aneurysms treated by neck clipping without bypass surgery was evaluated. Visual impairments included decreased visual acuity and visual field defect. The aneurysm was classified into superior projecting aneurysm, ventral projecting aneurysm, and carotid cave aneurysm. Plug-in method was defined as filling interspace, which was formed between the internal carotid artery and the sutured dura in case of detachment of the dural ring. RESULTS: Postoperative new visual impairments were observed in 30 aneurysms (22%). During the follow-up period (median, 600 days), postoperative new visual impairments continued in 23 aneurysms (17%). Multivariate analysis showed that carotid cave location and plug-in method were related to new visual impairments at 30 days (odds ratio [OR], 2.6; 95% confidence interval [CI] 1.1-6.1; P = 0.031 and OR, 4.1; 95% CI 1.4-12; P = 0.008) and at 6 months (OR, 4.1; 95% CI 1.5-11; P = 0.005 and OR, 3.3; 95% CI 1.1-11; P = 0.045). CONCLUSIONS: The present study showed that carotid cave location and plug-in method during dural closures were related to postoperative continued visual impairments. Neurosurgeons should carefully consider the surgical indication for unruptured carotid cave aneurysms and avoid plug-in methods.

MicroRNA-29a: A potential biomarker in the development of intracranial aneurysm.

AIM: To identify serum microRNA-29a (miR-29a) level in patients with intracranial aneurysm and its role in the development of intracranial aneurysm (IA). METHODS: Case group included 165 IA patients hospitalized in the department of neurosurgery between January 2010 and January 2012 while control group enrolled 220 healthy volunteers. Morning fasting blood samples were collected from peripheral vein. RT-PCR was used for miR-29a detection. Receiver Operating Characteristic (ROC) curve was drawn. Survival curves were drawn for survival analysis with Kaplan-Meier method and Long-rank test was conducted. MiR-29a expression Glasgow Prognosis Score (GOS) was used for prognosis scaling. Multivariate Cox proportional hazards regression analysis was performed for prognosis analysis. Results Cases had significantly higher miR-29a expressions than controls (P<0.05). ROC curve analysis indicated that miR-29a expression in IA had high effectiveness in IA diagnosis. Close associations were identified between miR-29a expression and rupture, Hunt-Hess level and surgical timing (all P<0.05). GOS strongly associated with history of hypertension, aneurysm location, rupture, Hunt-Hess level and miR-29a expression. Patients with low miR-29a expression had longer disease-free survival (DFS) and overall survival (OS) than those with high miR-29a expression (both P<0.05). MiR-29a expression, tumor aneurysm, rupture and Hunt-Hess were risk factors to the prognosis of IA (all P<0.05). CONCLUSION: MiR-29a may be closely related to IA development and therefore could be a useful predicator of IA prognosis, providing a new target for IA therapy.

Ruptured aneurysm at the cortical segment of the distal posterior inferior cerebellar artery associated with hemodynamic stress after basilar artery occlusion.

BACKGROUND: A distal posterior inferior cerebellar artery (PICA) de novo aneurysm at the cortical segment after atherosclerotic basilar artery occlusion is extremely rare. Here, we report the case of a ruptured distal PICA de novo aneurysm 8 years after basilar artery occlusion. CASE DESCRIPTION: A 75-year-old man experienced sudden disturbance of consciousness; computed tomography demonstrated cerebellar and subarachnoid hemorrhage due to a ruptured distal PICA aneurysm. Neck clipping of the aneurysm prevented re-rupture initially, and superficial temporal artery-superior cerebellar artery (STA-SCA) bypass was performed 3 months after admission. Postoperative angiography confirmed patency of the bypass, and the patient was discharged without any new neurological deficits. CONCLUSION: This report describes a case of de novo development of a saccular distal PICA aneurysm after atherosclerotic basilar artery occlusion. We believe that increased hemodynamic stress at the PICA might have contributed to the occurrence and rupture of the aneurysm. STA-SCA bypass, introduced in the territory of the cerebellar hemisphere, reduces hemodynamic stress, which would prevent the occurrence of de novo aneurysm and recurrent bleeding.

Subarachnoid hemorrhage caused by a traffic accident: de novo aneurysm ruptured 30 years after surgical neck clipping.

A man, who had a medical history of surgical neck clipping 30 years previously, died of traffic accident. The medico-legal autopsy showed subarachnoid hemorrhage and ruptured aneurysm on the lateral side of the clip. Microscopic examination showed the aneurysm was not to be regeneration, but a new de novo aneurysm. We diagnosed the cause of death was traumatic aneurysmal rupture. In addition, we discussed the cause of a newly formed de novo aneurysm which may be affected by past surgical neck clipping.