Endoscopic Evacuation of Acute Subdural Hematomas: A New Selection Criterion.

Introduction Acute subdural hematomas (ASDHs) have a high mortality rate and unfavorable outcomes especially in the elderly population even after surgery is performed. The conventional recommended surgeries by the Brain Trauma Foundation in 2006 were craniotomies or craniectomies for ASDH. As the world population ages, and endoscopic techniques improve, endoscopic surgery should be utilized to improve the outcomes in elderly patients with ASDH. Materials and Methods This was a single-center retrospective report on our series of six patients that underwent endoscopic ASDH evacuation (EASE). Demographic data, the contralateral global cortical atrophy (GCA) score, evacuation rates, and outcomes were analyzed. Results All patients' symptoms and Glasgow Coma Scale improved or were similar after EASE with no complications. Good outcome was seen in 4 (66.7%) patients. Patients with poor outcome had initial low Glasgow Coma Scale scores on admission. The higher the contralateral GCA score, the higher the evacuation rate ( r = 0.825, p ≤ 0.043). All the patients had a GCA score of ≥7. Conclusion EASE is at least not inferior to craniotomy for the elderly population in terms of functional outcome for now. Using the contralateral GCA score may help identify suitable patients for this technique instead of just using a cut-off age as a criteria.

[Pure Endoscopic Microvascular Decompression for Trigeminal Neuralgia and Hemifacial Spasm].

The panoramic view offered by endoscopy has been used to observe neurovascular compression in endoscope-assisted microsurgery to compensate for the blind spots in microvascular decompression(MVD)for trigeminal neuralgia and hemifacial spasm. In recent years, purely endoscopic MVD has been performed as a minimally invasive surgery and has become a new surgical technique for MVD. Endoscopic MVD has gained acceptance, and further developments are expected. Here, we present endoscopic MVD, including the setup, equipment, surgical procedures, and decompression techniques by transposition, as well as representative cases, and discuss the future prospects and possibilities of endoscopic MVD.

How I do it: endoscopic microvascular decompression for hemifacial spasm associated with anterior inferior cerebellar artery-posterior inferior cerebellar artery common trunk.

BACKGROUND: Multiple vessels from the anterior inferior cerebellar artery-posterior inferior cerebellar artery common trunk (APC) variation of the posterior circulation can cause hemifacial spasm (HFS). METHOD: Endoscopic microvascular decompression (eMVD) was performed using 0° and 30° endoscopes through a retrosigmoid keyhole. The root exit zone (REZ) was decompressed by transpositioning the offending anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA) arising from the APC under excellent endoscopic view. CONCLUSION: eMVD is an advanced, minimally invasive and reliable technique to resolve the neurovascular conflict (NVC) in HFS due to offenders from APC.

Computational Fluid Dynamics Analysis of Trigeminal Neuralgia Associated with the Vertebral Artery: A Report of Two Cases.

Trigeminal neuralgia is a nerve disorder that causes unilateral severe facial pain. The clinical features of trigeminal neuralgia are agonizing, paroxysmal, anticipated in one or more divisions of the trigeminal nerve, with repetitive bursts of a few seconds, exacerbated by cutaneous stimuli. Microvascular decompression is proven effective, resulting in a positive outcome. Here, we report two cases of trigeminal neuralgia associated with the vertebral artery, who underwent endoscopic microvascular decompression. This case report aims to show the benefit of computational fluid dynamics evaluation of the neurovascular contact and its effect on change in wall shear stress magnitude of the offending vertebral artery after surgical management with microvascular decompression.

Questionnaire for Dental Practitioners to Screen for Trigeminal Neuralgia.

Objective Trigeminal neuralgia (TN) is a neurological disorder that often presents as severe toothache. The majority of TN patients visit dental clinics first, so TN represents a potential pitfall for dental practitioners. This report describes the development of a trigeminal neuralgia questionnaire (TNQ), assessing 10 characteristics of TN, to assist dentists in screening for TN in dental clinics, and evaluates the effectiveness of TNQ. Materials and Methods Fifty-three patients who visited the TN outpatient department in our institute and completed the TNQ were included in this study. All patients were examined by two neurosurgeons and neuroimaging was performed. Statistical Analysis Patients were classified into a TN group and a non-TN group. TNQ score was retrospectively compared between groups. Furthermore, history and characteristics of TN were investigated in the TN group to clarify the status of the reference situation. Results Thirty-seven cases were assigned to the TN group, and 16 cases to the non-TN group. Mean TNQ score was 8.3 in the TN group and 6.6 in the non-TN group. Setting a TNQ cutoff score of 7 offered 91% sensitivity and 56% specificity for TN. Investigation of the history of the present illness indicated that 39.2% of TN cases were improperly triaged and referred from initial dental clinics, and interdisciplinary practice was insufficient. Conclusion TNQ offers a reliable, convenient method to triage TN patients, and may assist dentists in screening for TN. Multidisciplinary practice is necessary for total management of TN and the TNQ is expected to connect dentists and TN specialists.

Preoperative detailed evaluation intracranial artery stenosis using three-dimensional visualization analysis reduces the invasiveness of superficial temporal artery-middle cerebral artery bypass.

Objectives: Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery is a common treatment for preventing cerebral ischemia in patients with intracranial artery stenosis. The aim of this study was to analyze the surgical outcomes of the STA-MCA bypass procedure, particularly with regard to the invasiveness of targeted bypass (TB) with preoperative planning using Amira® software. Methods: Consecutive patients with single STA-MCA bypass performed by a single neurosurgeon from January 2019 to May 2022 were included. The clinical parameters of seven TB patients were compared with those of 11 patients treated with the conventional method (CM). Results: Compared with CM patients, TB using Amira® software patients had a shorter scalp incision (median [interquartile range]=11.2 [9.7-12.7] cm vs. 16.9 [16.0-17.7] cm, respectively; p=0.004], smaller craniotomy size (11.8 [11.5-14.4] cm2 vs. 20.9 [17.1-22.2] cm2, respectively; p=0.01], shorter surgery duration (201 [195-218] min vs. 277 [229-310] min, respectively; p=0.003], and less intraoperative bleeding (10 [10-20] g vs. 23 [20-50] g, respectively; p=0.033]. However, there were no differences in surgical complications between the two groups. Conclusions: Detailed preoperative evaluation using Amira® software can reduce the invasiveness of the STA-MCA bypass procedure.

How I do it: Endoscopic microvascular decompression for a nerve penetrating trigeminocerebellar artery causing trigeminal neuralgia.

BACKGROUND: The trigeminocerebellar artery is a standard variant originating from the basilar artery and can be an infrequent cause of trigeminal neuralgia. METHOD: Total endoscopic microvascular decompression (eMVD) was performed using a 0-degree endoscope through a retro sigmoid keyhole. Multiple points of neurovascular conflict enhanced by indocyanine green angiography were identified, and the root entry zone was decompressed. The patient had an improvement in facial pain with no complications. CONCLUSION: Complete eMVD for a nerve-penetrating artery is a practical, minimally invasive, uncomplicated technique that improves visualization and patient comfort.

Contrast-Induced Encephalopathy after Endovascular Treatment: Two Case Reports.

Contrast-induced encephalopathy (CIE) is a rare neurological complication that occurs after the use of contrast medium in various angiographic procedures. Symptoms can be different, from headache to severe neurological deficit and coma. In the articles published to date, symptoms appeared immediately after application of contrast agent or within 24 hours. Here we present two cases of patients in whom CIE developed delayed after endovascular treatment.

Predicting Morphological Changes to Vessel Walls Adjacent to Unruptured Cerebral Aneurysms Using Computational Fluid Dynamics.

Objective This study compared intraoperative findings with preoperative computed tomography angiography (CTA) and computational fluid dynamics (CFD) analysis of perianeurysmal findings for the indication of possible vessel wall thinning. Materials and Methods Participants comprised 38 patients with unruptured middle cerebral artery aneurysms treated by surgical clipping at our hospital between May 2020 and April 2021. We defined parent artery radiation sign (PARS) as the presence of each of the following three findings in CFD analysis based on preoperative CTA: (1) impingement of the stream line on the outer parent vessel wall of the aneurysm; (2) radiation of wall shear stress vectors outwards from the same site; and (3) increased wall pressure compared with the surrounding area. CFD analysis showing PARS was compared with intraoperative findings. Results In all nine cases with PARS, no morphological abnormalities were found in the same area on CTA. However, intraoperative findings showed thinning of the parent artery wall in one of the nine cases and formation of a very small mass in three cases, differing from CTA findings. All nine patients underwent additional clipping and/or wrapping and coating at the site of PARS. Conclusion Detecting thinning of the vessel wall or the presence of a microaneurysm may be difficult in endovascular therapy, which is based on the visualization of the vessel lumen. CFD analysis suggests the necessity of confirming findings for the vessel wall around an aneurysm by direct manipulation, as the presence of PARS may indicate partial thinning of the vessel wall or formation of a microaneurysm.

Coexistence of neurovascular compression syndrome and unruptured cerebral aneurysm.

Unruptured cerebral aneurysms (UCAs) are usually asymptomatic and detected incidentally by intracranial examinations. The coexistence of neurovascular compression syndrome (NVCS) and UCAs has not been well described. The aim of this study was to clarify the characteristics of UCAs with the NVCS. A total of 103 cases that underwent microvascular decompression (MVD) for trigeminal neuralgia (TN) or hemifacial spasm (HFS) were assigned to the NVCS group. The prevalence of UCAs in the NVCS group was compared retrospectively to that in 110 control cases (a control group) by neuro-imaging. Overall treatment courses for NVCS and UCAs were investigated in the NVCS group. Sixteen (15.3%; TN 11 cases, HFS 5 cases) of 103 MVD cases had 19 UCAs, a significantly higher prevalence than the 3.6% in the control group. Binomial logistic regression showed that NVCS is a significant factor for predicting the presence of UCAs, with an odds ratio of 4.80. In the NVCS group, 18 UCAs (94.7%) were supratentorial aneurysms, and 17 UCAs (89.5%) were less than 5 mm in size. Nine UCAs were surgically treated with clipping or coiling. Of the surgical cases, 2 UCAs were treated before MVD for NVCS, whereas the other 7 UCAs were treated after MVD. No aneurysms ruptured during the treatment course. The NVCS occurred with UCAs at a significantly higher rate than in the control group. Most UCAs with the NVCS were supratentorial, small aneurysms that did not affect the surgical treatment of NVCS.

Depiction of Cerebral Aneurysm Wall by Computational Fluid Dynamics (CFD) and Preoperative Illustration.

Introduction Preoperative illustration is a part of an important exercise to study the configuration, direction, and presence of any perforations, and is the weakest point in the wall of the cerebral aneurysm. The same illustration is used to study the surrounding brain structures to decide the best and safe surgical approach prior to any surgical procedure. With the evolution of the aneurysm wall study and study of flow dynamic within the involved artery and its aneurysm wall using computational fluid dynamics (CFD), a better surgical plan can be formulated to improve the flow dynamics. As one of the clinical applications of CFD, we propose a study using a composite image that combines preoperative illustration and CFD, which is traditionally widely used in neurosurgery. Methods and Materials We study the use of illustrations of the unruptured cerebral aneurysm of internal carotid-posterior communicating (ICPC) artery and anterior communicating artery (AcomA) treated at our hospital. The combinations of both preoperative illustrations and CFD images by using "ipad Pro" were used. Result and Conclusion Medical illustration in the preoperative study of unruptured cerebral aneurysm with combinations of CFD and surrounding brain structures is helpful to decide the surgical approaches and successful surgical treatments.

Preoperative 3D Image Evaluation of EC-IC Bypass by 3D Visualization Analysis Software Amira®.

Background: Careful evaluation of the preoperative imaging for extracranial-intracranial bypass performed for conditions like intracranial stenosis and Moya disease is important. The traditional use of 2D imaging has a significant limitation for neurosurgeons, primarily to determine the optimal location of the recipient artery for performing the surgical bypass. Therefore, many neurosurgeons use 3D angiograms more frequently to overcome these shortcomings. Materials And Methods: We performed the preoperative evaluation of the possibility of performing an anastomosis between the superficial temporal artery and the middle cerebral artery (STA-MCA) bypass by synthesizing images of computerized tomography (CT), magnetic resonance imaging (MRI), and digital subtraction angiography (DSA) using Amira® of 3D visualization analysis software (Thermo Scientific Co.). Results: The 3D images prepared before surgery using this software showed good agreement with the intraoperative findings. Conclusion: Preoperative image processing using tools like Amira provide optimal information for good planning and communication for performing STA-MCA bypass and may become a helpful tool.

Carotid Artery Dissection and Aneurysm with Styloid Process Fracture.

Background: Mechanical stimulation may lead to internal carotid artery (ICA) dissection and aneurysm. Case Description: We encountered a rare case of ICA dissection and aneurysm with prolonged styloid process (SP) fracture. A 37-year-old sales worker presented with right-sided amaurosis fugax. After admission to a nearby optical clinic, he was admitted to our hospital. Computed tomography angiography (CTA) and digital subtraction angiography showed dissection and apparent aneurysmal change in the right cervical portion of the ICA. CTA also showed elongated SPs, so we diagnosed Eagle's syndrome, and fracture of the right-side process. After 2 weeks of antiplatelet therapy, the aneurysm enlarged and dissection remained, so we treated the patient with coil embolization and stenting. Conclusion: We encountered a rare case of ICA dissection and aneurysm with Eagle's syndrome. Endovascular treatment was performed because the SP was fractured.

How I do it: two-step transposition technique during endoscopic microvascular decompression for trigeminal neuralgia.

BACKGROUND: Endoscopic microvascular decompression (eMVD) provides excellent visualization and minimally invasive surgical treatment of trigeminal neuralgia (TN). The transposition technique is desirable for long-term outcomes of TN. METHOD: A two-step transposition technique is performed during eMVD for TN due to the arch-shaped superior cerebellar artery (SCA). First, the cerebellomesencephalic segment of the SCA is pulled out using oxycellulose balls. Second, the retracted lateral pontomesencephalic segment of the SCA is detached from the trigeminal nerve and is transposed for fixation at the tentorium cerebelli. CONCLUSION: The two-step transposition technique offers simple, reliable decompression for TN due to the arch-shaped SCA.

How I do it: Management of venous bleeding from the superior petrosal vein during endoscopic microvascular decompression.

BACKGROUND: A repair strategy for venous bleeding from the superior petrosal vein (SPV) is essential during endoscopic microvascular decompression. METHOD: Sliced oxycellulose seats are rounded off, making balls around 10 mm in diameter. When venous bleeding arises from the SPV, the first oxycellulose ball is placed just behind the SPV in the surgical view. A second ball is then applied in front of the SPV. The SPV is thus immediately and entirely covered by oxycellulose, and hemostasis is safely achieved with the preservation of the SPV. CONCLUSION: This oxycellulose ball technique offers simple, reliable control of venous bleeding from the SPV.

How I do it: endoscopic microvascular decompression for glossopharyngeal neuralgia.

BACKGROUND: Microvascular decompression (MVD) for glossopharyngeal neuralgia (GPN) is associated with high complication and incomplete cure rates because of its poor ability to visualize neurovascular conflicts. METHOD: Fully endoscopic MVD for GPN was carried out through a retrosigmoid keyhole approach. Neurovascular conflicts were clearly demonstrated with a loop of the posterior inferior cerebellar artery (PICA) under a 30° endoscopic view, and no significant cerebellar retraction was observed. The loop of the PICA was safely decompressed and the perforators were preserved while offering an excellent operative view. CONCLUSION: Endoscopic MVD is a reliable and minimally invasive method for GPN.

Clinical significance of centripetal propagation of vasoconstriction in patients with reversible cerebral vasoconstriction syndrome: A retrospective case-control study.

Introduction We previously reported centripetal propagation of vasoconstriction at the time of thunderclap headache remission in patients with reversible cerebral vasoconstriction syndrome. Here we examine the clinical significance of centripetal propagation of vasoconstriction. Methods Participants comprised 48 patients who underwent magnetic resonance angiography within 72 h of reversible cerebral vasoconstriction syndrome onset and within 48 h of thunderclap headache remission. Results In 24 of the 48 patients (50%), centripetal propagation of vasoconstriction occurred on magnetic resonance angiography at the time of thunderclap headache remission. The interval from first to last thunderclap headache in patients with centripetal propagation of vasoconstriction (14 ± 10 days) was significantly longer than that of patients without centripetal propagation of vasoconstriction (4 ± 2 days). In the patients with centripetal propagation of vasoconstriction at the time of thunderclap headache remission, the incidence of another cerebral lesion (38%, 9 of 24 cases) was significantly higher than in patients without centripetal propagation of vasoconstriction (0%). From findings of sequential magnetic resonance angiography before and after thunderclap headache remission, we observed tendencies in which centripetal propagation of vasoconstriction gradually progressed after the onset of reversible cerebral vasoconstriction syndrome and peaked at the time of thunderclap headache remission. The progress of centripetal propagation of vasoconstriction concluded with thunderclap headache remission. Conclusions Centripetal propagation of vasoconstriction has clinical significance as an indicator of the severity of reversible cerebral vasoconstriction syndrome. The presence of centripetal propagation of vasoconstriction is associated with an increased risk of brain lesions and a longer interval from first to last thunderclap headache. Moreover, repeat magnetic resonance angiography to assess centripetal propagation of vasoconstriction during the time from onset to thunderclap headache remission can help diagnose reversible cerebral vasoconstriction syndrome.

Endoscopic extradural supraorbital approach to the temporal pole and adjacent area: technical note.

The authors' initial experience with the endoscopic extradural supraorbital approach to the temporal pole and adjacent area is reported. Fully endoscopic surgery using the extradural space via a supraorbital keyhole was performed for tumors in or around the temporal pole, including temporal pole cavernous angioma, sphenoid ridge meningioma, and cavernous sinus pituitary adenoma, mainly using 4-mm, 0° and 30° endoscopes and single-shaft instruments. After making a supraorbital keyhole, a 4-mm, 30° endoscope was advanced into the extradural space of the anterior cranial fossa during lifting of the dura mater. Following identification of the sphenoid ridge, orbital roof, and anterior clinoid process, the bone lateral to the orbital roof was drilled off until the dura mater of the anterior aspect of the temporal lobe was exposed. The dura mater of the temporal lobe was incised and opened, exposing the temporal pole under a 4-mm, 0° endoscope. Tumors in or around the temporal pole were safely removed under a superb view through the extradural corridor. The endoscopic extradural supraorbital approach was technically feasible and safe. The anterior trajectory to the temporal pole using the extradural space under endoscopy provided excellent visibility, allowing minimally invasive surgery. Further surgical experience and development of specialized instruments would promote this approach as an alternative surgical option.

Retrospective review of previous minor leak before major subarachnoid hemorrhage diagnosed by MRI as a predictor of occurrence of symptomatic delayed cerebral ischemia.

OBJECTIVE This study attempted to determine whether a previous minor leak correlated with the occurrence of symptomatic delayed cerebral ischemia (sDCI). METHODS The authors retrospectively evaluated sDCI-related clinical features and findings from MRI, including T1-weighted imaging (T1WI)-FLAIR mismatch at the time of admission, in 151 patients admitted with subarachnoid hemorrhage (SAH) within 48 hours of ictus. RESULTS The overall incidence of sDCI was 23% (35 of 151 patients). In all subjects, multivariate analysis revealed that World Federation of Neurosurgical Societies Grades II-V, age 70 years or older, presence of rebleeding after admission, a previous minor leak before the major SAH attack as diagnosed by T1WI-FLAIR mismatch, acute infarction on diffusion-weighted imaging, and CT SAH score were significantly associated with occurrence of sDCI. In patients with no previous minor leak before major SAH as diagnosed by T1WI-FLAIR mismatch, the incidence of sDCI was only 7% (7 of 97 patients). CONCLUSIONS A previous minor leak before major SAH as diagnosed by T1WI-FLAIR mismatch represents an important sDCI-related factor. When the analysis was restricted to patients with true acute SAH without a previous minor leak diagnosed by T1WI-FLAIR mismatch, the incidence of sDCI was extremely low.

How I do it: endoscopic microvascular decompression for hemifacial spasm associated with the vertebral artery.

BACKGROUND: Microvascular decompression (MVD) of hemifacial spasm (HFS) associated with the vertebral artery (VA) shows higher rates of incomplete cure and complications compared to non-VA-related HFS. METHOD: Purely endoscopic MVD for VA-associated HFS via a retrosigmoid keyhole was performed. Neurovascular conflicts by a directly offending artery and VA around the root exit zone of the facial nerve were clearly demonstrated under 30° endoscopic view without significant cerebellar retraction. The VA and directly offending artery were safely transposed with preservation of perforators under excellent view. CONCLUSION: Endoscopic MVD offers reliable decompression for VA-associated HFS with minimal invasiveness.