Functional Outcomes of Microsurgical Resection for Cavernous Malformations of the Brainstem.

Long-term functional outcomes of microsurgical resection for cavernous malformations of the brainstem (CMB) have been largely unknown. Favorable outcomes after CMB surgery might be related to the achievement of complete resection and mRS at 1 month after the surgery. Preoperative sensory, cerebellar, trigeminal nerve, and lower cranial nerve symptoms tended to improve after surgery.We evaluated 25 consecutive patients with CMB surgically treated at our center between 2006 and 2021. The subjects included 11 men and 14 women, with ages ranging from 13 to 61 years (mean ± SD = 37 ± 12 years). Modified Rankin Scale (mRS) scores and neurological symptoms of the patients were evaluated before surgery, 1 month after surgery, and at the final follow-up at the outpatient clinic. The mean number of previous hemorrhages was 7 ± 1.0 and the mean lesion size was 21 ± 8 mm. The mRS scores on admission and at the final follow-up were 2.9 points and 1.7 points, respectively. The mRS scores at the final follow-up were significantly improved compared to those on admission. There was no statistical difference between the preoperative mRS and mRS at 1 month after the operation. Multivariable analysis indicated that mRS scores at 1 month after surgery were the most significant predictive factors for favorable outcomes. Complete resection was achieved in 24 of 33 operations. Incomplete resection was significantly related to the frequency of subsequent recurrent hemorrhage and high mRS scores at the final follow-up. Preoperative sensory, cerebellar, trigeminal nerve, and lower cranial nerve symptoms improved significantly after surgery.

Factors affecting global neurocognitive status and frontal executive functions in the early stage after surgical clipping of unruptured anterior circulation aneurysms with respect to keyhole clipping and conventional clipping.

PURPOSE: This study investigated the most significant factor for the preservation of the global neurocognitive status and frontal executive functions in the surgical clipping of unruptured anterior circulation aneurysms, specifically in keyhole and conventional clipping procedures. METHODS: The prospective study that was performed to examine the effects of aneurysm surgery on the patient's global neurocognitive status and frontal executive functions started on April 2016. After exclusion posterior circulation aneurysms, anterior communicating aneurysms treated by interhemispheric approach, giant aneurysms, and paraclinoid aneurysms, 23 patients who were enrolled before May 2017 were treated by conventional clipping, and 18 patients who were enrolled after June 2017 were treated by keyhole clipping. Two patients were excluded from each group due to missing data. Finally, 21 and 16 patients in each group were analyzed, respectively. Three-tesla magnetic resonance imaging was performed before and after surgery to detect the presence of perioperative cerebral infarctions and brain edema. The Mini-Mental State Examination, Frontal Assessment Battery, and Self-Rating Depression Scale scores were obtained before and 1 month after surgery. RESULTS: Logistic regression analyses indicated that anterior communicating and internal carotid artery aneurysms were the most significant factors for poor outcomes and that keyhole clipping for these two types of aneurysm was the most significant factor for the preservation of patient global neurocognitive status. Keyhole clipping was also the most significant factor for the preservation of frontal executive functions in patients. CONCLUSIONS: Keyhole clipping may be more favorable than conventional clipping for the preservation of the global neurocognitive status and frontal executive functions. Moreover, it may be the most effective factor for preservation of global neurocognitive status when it is indicated for anterior communicating or internal carotid artery aneurysms.

[Vestibular Schwannoma Surgery with Continuous Intraoperative Monitoring of Evoked Facial Nerve Electromyograms].

Preservation of facial nerve function is crucial during vestibular schwannoma surgery. Here, we report the utility of continuous intraoperative monitoring of evoked facial nerve electromyograms(EMGs)for preservation of facial nerve function during vestibular schwannoma surgery. A 64-year-old man presented with left ear hearing disturbance. CT and MRI revealed a tumor mass(4cm)with cyst formation in the left cerebellopontine angle. Microsurgical removal was performed with continuous intraoperative monitoring of evoked facial nerve EMGs. An electrode with Ag wire and absorbable gelatin sponge, which we developed, was used for continuous monitoring. It could be placed and fixed more easily on the root exit zone of the facial nerve than the previously reported electrodes and provide reliable information during surgery. The tumor mass could be removed safely without inducing facial nerve palsy. Continuous intraoperative monitoring of evoked facial nerve EMGs with this newly developed electrode could facilitate successful schwannoma surgery.

Skull Subsidence due to Periosteum Defect following Craniotomy in a Child.

We report a case of a 7-year-old child with a cranial deformity secondary to a craniotomy for an intracranial hematoma. He suffered from an acute epidural hematoma with a lineal fracture of the right temporal bone following a severe head injury. A large question mark-shaped skin flap with the periosteum and temporal muscle was created for a decompressive craniectomy; however, neither the acute epidural hematoma nor brain swelling was severe, and we performed a small craniotomy compared with the skin flap without a decompressive craniectomy. Eighteen months after the operation, he complained of skull deformity with a mild depression of the forehead. Axial and 3-dimensional computed tomography showed thinness and subsidence of the frontoparietal bone around the replaced bone flap, corresponding to the skin flap with the periosteum defect. We suggest that the periosteum defect following creation of the skin flap during surgery prevented normal growth of the skull, which caused the thinness and subsidence of the frontoparietal bone. Preservation and cooptation of the periosteum should be performed during neurological surgeries in babies and children to prevent skull deformity.

Anatomy of the Frontal Sinus Drainage Pathway Evaluated in 247 Cadavers to Prevent Cerebrospinal Fluid Leakage After Frontobasal Craniotomy.

BACKGROUND AND OBJECTIVES: The frontal sinus (FS) drainage pathway (FSDP) may be a conduit for cerebrospinal fluid leakage after frontobasal craniotomy. In this cadaveric study, we aimed to evaluate the anatomy of the FSDP. METHODS: The FSs and FSDPs of 247 cadavers were investigated. We counted the number of FSs and FSDPs in each half-head, verified the presence of a narrowing section in each FSDP, and evaluated the depth, shape, and size of each narrowing FSDP section. RESULTS: We investigated 494 sides and 472 FSDPs of 247 cadavers. FSs were unilaterally undeveloped in 13 of 247 cadavers (5.3%) and bilaterally in 8 (3.2%). FSs were unilaterally duplicated in 7 of 247 cadavers (2.8%), and no FSs were bilaterally duplicated or triplicated. No FSs had 2 or more FSDPs, and all 472 investigated FSDPs were invariably narrowed at various depths. The narrowing FSDP sections were elliptical (78.6%), circular (18.1%), triangular (1.8%), or crescent-shaped (1.4%) and of varying thickness and orientation. Although FSDPs were asymmetric in 92.2% of cadavers and narrowing FSDP sections were located deep (8.9 ± 4.4 mm from the anterior skull base), the narrowing FSDP sections were typically small (area: 5.9 ± 3.3 mm 2 ) or thin (short diameter: 2.1 ± 0.7 mm). CONCLUSION: Each FS had only one FSDP, all FSDPs were invariably narrowed at various depths, and the narrowing FSDP sections were sufficiently small or thin to allow local closure, facilitating prevention of cerebrospinal fluid leakage after frontobasal craniotomy.

Prediction of Occurrence of Cerebral Infarction After Successful Mechanical Thrombectomy for Ischemic Stroke in the Anterior Circulation by Arterial Spin Labeling.

PURPOSE: The overall goal of our study is to create modified Alberta Stroke Program Early Computed Tomography Score (ASPECTS) determined by the findings on arterial spin labeling imaging (ASL) to predict the prognosis of patients with acute ischemic stroke after successful mechanical thrombectomy (MT). Prior to that, we examined predictive factors including the value of cerebral blood flow (CBF) measured by ASL for occurrence of cerebral infarction at the region of interest (ROI) used in the ASPECTS after successful MT. METHODS: Of the 92 consecutive patients with acute ischemic stroke treated with MT at our institution between April 2013 and April 2021, a total of 26 patients who arrived within 8 h after stroke onset and underwent MT resulting in a thrombolysis in cerebral infarction score of 2B or 3 were analyzed. Magnetic resonance imaging, including diffusion-weighted imaging (DWI) and ASL, was performed on arrival and the day after MT. The asymmetry index (AI) of CBF by ASL (ASL-CBF) before MT was calculated for 11 regions of interest using the DWI-Alberta Stroke Program Early CT Score. RESULTS: Occurrence of infarction after successful MT for ischemic stroke in the anterior circulation can be expected when the formula 0.3211â€¯× history of atrial fibrillation +0.0096â€¯× the AI of ASL-CBF before MT (%) +0.0012â€¯× the time from onset to reperfusion (min) yields a value below 1.0 or when the AI of ASL-CBF before MT is below 61.5%. CONCLUSION: The AI of ASL-CBF before MT or a combination of a history of atrial fibrillation, the AI of ASL-CBF before MT, and the time from onset to reperfusion can be used to predict the occurrence of infarction in patients arriving within 8 h after stroke onset in which reperfusion with MT was successful.

Visual Evoked Potential Can Predict Deterioration of Visual Function After Direct Clipping of Paraclinoid Aneurysm With Anterior Clinoidectomy.

BACKGROUND: The role of visual evoked potential (VEP) in direct clipping of the paraclinoid internal carotid artery (ICA) aneurysm remains uncertain. OBJECTIVE: To examine whether intraoperative neuromonitoring with VEP can predict deterioration of visual function after direct clipping of the paraclinoid ICA aneurysm with anterior clinoidectomy. METHODS: Among consecutive 274 patients with unruptured cerebral aneurysm, we enrolled 25 patients with paraclinoid ICA aneurysm treated by direct clipping after anterior clinoidectomy with intraoperative neuromonitoring with VEP in this study. We evaluated the visual acuity loss (VAL) and visual field loss (VFL) before surgery, 1 month after surgery, and at the final follow-up. RESULTS: The VAL at 1 month after surgery (VAL1M) and VAL at the final follow-up (Final VAL) were significantly related to the reduction rate of VEP amplitude at the end of surgery (RedEnd%), more than 76.5%, and the maximal reduction rate of VEP amplitude during surgery (MaxRed%), more than 66.7% to 70%. The VFL at 1 month after surgery (VFL1M) and the VFL at the final follow-up (Final VFL) were significantly related to MaxRed% more than 60.7%. CONCLUSION: VAL1M, Final VAL, VFL1M, and Final VFL could be significantly predicted by the value of RedEnd% and MaxRed% in direct clipping of Al-Rodhan group Ia, Ib, and II paraclinoid ICA aneurysms with anterior clinoidectomy.

Hyperplasia of Arachnoid Trabecular Cells: A Hitherto Undescribed Lesion Observed in the Setting of Neurofibromatosis Type 1.

Central nervous system manifestations, a variety of benign and malignant tumors as well as non-neoplastic abnormalities, are found in over 70% of neurofibromatosis type 1 (NF1) patients. Herein, we report hitherto undescribed space-occupying lesions in the setting of NF1. We aimed to clarify their characteristics, especially whether they represent neoplastic or non-neoplastic (hyperplastic) lesions. All 3 cases were preoperatively assessed as non-neoplastic; 2 and 1 cases were suspected to be arachnoid cysts and dilation of subarachnoid space, respectively. However, all lesions were revealed to be whitish jelly-like masses by operation, and the histology composed of spindle cells resembling arachnoid trabecular cells with moderate cellularity and cellular uniformity gave an impression that these lesions may be neoplastic. In contrast, electron microscopic analysis showed that the characteristics of these cells were compatible with those of normal arachnoid trabecular cells. Furthermore, whole-exome sequencing and array comparative genomic hybridization did not show any obvious alterations suggestive of their neoplastic nature. DNA methylation analysis demonstrated that these lesions were epigenetically distinct not only from meningiomas but also from normal healthy meninges. In conclusion, considering the clinicopathologic aspects of the present lesions and the results of the molecular analysis that failed to suggest their neoplastic nature, they may represent previously unrecognized rare hyperplasia of arachnoid trabecular cells, which may be associated with NF1.

Effect of newly developed scissors-attached micro-forceps on the recipient clamp time and occurrence of anastomotic site infarction after bypass surgery for moyamoya disease.

Introduction: This study aimed to examine the effect of newly developed scissors-attached micro-forceps in superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease (MMD). Materials and methods: Of 179 consecutive STA-MCA anastomoses on 95 hemispheres of 71 MMD patients at the University of Fukui Hospital between 2009 and 2023, 49 anastomoses on 26 hemispheres of 21 patients were enrolled in this retrospective cohort clinical trial intraoperative indocyanine green video-angiography did not demonstrate bypass patency in three anastomoses in two patients who were excluded. Twenty-one anastomosis in 19 hemispheres of 16 patients were performed using the conventional micro-forceps (conventional group, CG), and 25 anastomoses in 22 hemispheres of 19 patients were performed using scissors-attached micro-forceps (scissors group, SG). A small infarction near the anastomotic site detected using postoperative diffusion-weighted imaging was defined as anastomotic site infarction (ASI). Factors affecting the occurrence of ASI were examined by univariate, logistic regression, and receiver operating curve (ROC) analysis. Results: There were no significant differences in clinical parameters such as age, sex, number of sacrificed branches, number of sacrificed large branches, and number of sutures between the CG and SG. However, the clamp time and occurrence of ASI were significantly lower in the SG than in the CG. Logistic regression analysis revealed that the clamp time was the only significant factor predicting the occurrence of ASI. A receiver operating curve analysis also revealed that the clamp time significantly predicted the occurrence of ASI (area under the curve, 0.875; cutoff value, 33.2 min). Conclusion: The newly developed scissors-attached micro-forceps could significantly reduce the clamp time and occurrence of ASI in STA-MCA anastomosis for MMD.

Prediction of Post-operative Long-Term Outcome of the Motor Function by Multimodal Intraoperative Neuromonitoring With Transcranial Motor-Evoked Potential and Spinal Cord-Evoked Potential After Microsurgical Resection for Spinal Cord Tumors.

Objective: To examine the effect of multimodal intraoperative neuromonitoring on the long-term outcome of motor function after microsurgical resection for spinal cord tumors. Materials and Methods: Consecutive fourteen patients with spinal tumors who were surgically treated at the University of Fukui Hospital between 2009 and 2020 [M:F = 10:4, ages ranging from 22 to 83 years (mean ± SD = 58 ± 21 years)] were included in this study. There were eight intra-axial tumors and six extra-axial tumors. There were four patients with hypertension, two patients with diabetes mellitus, and four patients with hyperlipidemia. Three patients were under antithrombotic medication, two were under steroid medication, four were current smokers, and four were current drinkers. Manual muscle test (MMT) of the upper and lower extremities of the patients was examined before surgery, 2 weeks after surgery, and at the final follow-up. The mean follow-up period was 38 ± 37 months. McCormick scores were examined before surgery and at the final follow-up. Microsurgical resection of the tumor was underwent through the posterior approach under transcranial motor-evoked potential (TcMEP) monitoring. The MEP of 46 extremities was recorded during the surgery. Gross total resection was achieved in 13 of 14 surgeries. Spinal cord-evoked potential (Sp-SCEP) monitoring was performed in eight of 14 patients. Results: The length of peritumoral edema was significantly longer in patients with deterioration of McCormick scores than in patients with preservation of McCormick scores (p = 0.0274). Sp-SCEP could not predict the deterioration. The ratio of MEP at the beginning of the surgery to that at the end of the surgery was the only significant negative factor that predicts deterioration of motor function of the extremity at the final follow-up (p = 0.0374, odds ratio [OR] 1.02E-05, 95% CI 9.13E+01-7.15E+18). A receiver operating characteristic (ROC) analysis revealed that the cutoff value of the ratio of MEP to predict the deterioration at the final follow-up was 0.23 (specificity 100%, specificity 88%, positive predictive value 100%, and negative predictive value 88%) to predict deterioration at the final follow-up. Conclusions: Ratio MEP was the most significant negative factor to predict the deterioration of motor weakness at spinal tumor surgery. The setting of the cutoff value should be more strict as compared to the brain surgery and might be different depending on the institutions.

Quantitative Analysis of the Far-Lateral, Supra-Articular Transcondylar Transtubercular Approach Using Cadaveric Computed Tomography and Magnetic Resonance Imaging.

BACKGROUND: Removing the jugular tubercle (JT) is regarded as an important step in the far-lateral approach; however, few cadaveric studies have objectively evaluated it. OBJECTIVE: To quantitatively analyze the effect of JT removal in the far-lateral approach, using cadaveric computed tomography (CT) and magnetic resonance (MR) imaging. METHODS: The far-lateral, supra-articular transcondylar transtubercular approach was employed on 23 sides of 13 formalin-fixed cadaveric heads. CT bone images were obtained before and after JT removal, and MR images were obtained before dissection and were merged with the CT bone images. The angles of attack used to approach the ventral region of the medulla, the distances between the medulla and the bony structure, and the volume of the paramedullary space were measured at the level of the JT on axial CT-MR fusion images. The values obtained after JT removal were compared with those obtained before JT removal. RESULTS: All evaluated values were significantly increased after JT removal, including the angle of attack at the level of the JT (29.8 ± 7.4° vs 58.2 ± 15.5°, P < .001), the distance between the olive and the JT (6.4 ± 2.0 mm vs 9.5 ± 5.0 mm, P = .01), and the volume of the space around the medulla (0.28 ± 0.04 cm3 vs 0.47 ± 0.09 cm3, P < .001). CONCLUSION: The paramedullary surgical working space widened by JT removal was quantitatively demonstrated in the cadaveric CT and MR imaging study. The measurement methods in this study can be applied to clinical cases and other skull base cadaveric studies.

Spinal endoscopy combined with selective CT myelography for dural closure of the spinal dural defect with superficial siderosis: technical note.

The authors describe a new procedure to detect the tiny dural hole in patients with superficial siderosis (SS) and CSF leakage using a coronary angioscope system for spinal endoscopy and selective CT myelography using a spinal drainage tube. Under fluoroscopy, surgeons inserted the coronary angioscope into the spinal subarachnoid space, similar to the procedure of spinal drainage, and slowly advanced it to the cervical spine. The angioscope clearly showed the small dural hole and injured arachnoid membrane. One week later, the spinal drainage tube was inserted, and the tip of the drainage tube was located just below the level of the dural defect found by the spinal endoscopic examination. This selective CT myelography clarifies the location of the dural defect. During surgery, the small dural hole could be easily located, and it was securely sutured. It is sometimes difficult to detect the actual location of the small dural hole even with thin-slice MRI or dynamic CT myelography in patients with SS. The use of a coronary angioscope for the spinal endoscopy combined with selective CT myelography may provide an effective examination to assess dural closure of the spinal dural defect with SS in cases without obvious dural defects on conventional imaging.

Evaluation of the Use of Calcium Phosphate Cement for Aesthetic Neurosurgical Cranial Reconstruction.

OBJECTIVE: The objective of this article is to evaluate whether newly developed calcium phosphate cement (CPC), mounted around the titanium plates, is useful for aesthetic cranial reconstruction by using 2 methods. METHODS: The morphologic changes of CPC were observed in videos of 6 patients who had undergone cranial reconstruction with CPC during the first surgery and required second surgery. The facial aesthetic outcomes of 74 consecutive patients, more than 12 months after frontotemporal or bifrontal craniotomy and reconstruction with or without CPC, were evaluated. RESULTS: Observations of CPC changes were available 1 day, 2 weeks, 2 months, 5 months, 10 months, and 26 months after the first surgeries. CPC, applied superficially on the cranial surface, had not set sufficiently. CPCs, mounted thickly around the titanium plates and forming hydroxyapatite, were residual during the latter period. Comparison between the aesthetic reconstruction group (with CPC) and the simple reconstruction group (without CPC) showed that the objective bump detected by the investigator, and the subjective bump noticed by the patients themselves, were significantly more frequent in the simple reconstruction group. Comparison between the patients without an objective bump and the patients with an objective bump during the follow-up period showed that the proportion of patients after aesthetic cranial reconstruction with CPC was significantly higher in patients without an objective bump. Patients' characteristics, craniotomy procedure, use of a vascularized pericranial flap, and craniotomy-associated complications did not influence the objective bump significantly. CONCLUSIONS: Use of CPC was expected to bring better aesthetic outcomes after neurosurgical cranial reconstructions.

Pathological examination of cerebral amyloid angiopathy in patients who underwent removal of lobar hemorrhages.

Cerebral amyloid angiopathy (CAA) is a degenerative disorder characterized by amyloid-ß (Aß) deposition in the brain microvessels. CAA is also known to contribute not only to cortical microbleeds but also lobar hemorrhages. This retrospective study examined CAA pathologically in patients who underwent direct surgeries for lobar hemorrhage. Thirty-three patients with lobar hemorrhage underwent open surgery with biopsy from 2007 to 2016 in our hospital. Cortical tissues over hematomas obtained surgically were pathologically examined using hematoxylin, eosin stain, and anti-Aß antibody to diagnose CAA. We also investigated the advanced degree of CAA and clinical features of each patient with lobar hemorrhage. In the 33 patients, 4 yielded specimens that were insufficient to evaluate CAA pathologically. Twenty-four of the remaining 29 patients (82.8%) were pathologically diagnosed with CAA. The majority of CAA-positive patients had moderate or severe CAA based on a grading scale to estimate the advanced degree of CAA. About half of the CAA-positive patients had hypertension, and four took anticoagulant or antiplatelet agents. In five patients who were not pathologically diagnosed with CAA, one had severe liver function disorder, three had uncontrollable hypertension, and one had no obvious risk factor. Our pathological findings suggest that severe CAA with vasculopathic change markedly contributes to lobar hemorrhage. The coexistence of severe CAA and risk factors such as hypertension, anticoagulants or antiplatelets may readily induce lobar hemorrhage.

Orbitozygomatic Craniotomy with Modified Zabramski's Technique: A Technical Note and Anatomic and Clinical Findings.

BACKGROUND: The surgical technique of orbitozygomatic craniotomy reported by Zabramski et al. is an excellent procedure, facilitating wide surgical exposure, easy orbital reconstruction, and a satisfactory postsurgical aesthetic outcome; however, it is anatomically complicated and technically difficult. We introduce a simplified technique of Zabramski's orbitozygomatic craniotomy and present the anatomic and clinical findings with cadaveric photos, illustrations, and a video. METHODS: The orbitozygomatic craniotomy was performed on 20 sides of 11 cadaveric heads, in which the cut between the inferior orbital fissure and superior orbital fissure was modified and simplified, and the shortest distance between them was measured. This technique was applied to 13 clinical cases, and craniotomy-associated aesthetic and functional complications were evaluated. RESULTS: The average of the shortest distance from the inferior orbital fissure to superior orbital fissure was 21.3 mm (range, 19-23 mm) on the 20 sides of the 11 cadaveric heads. In all 13 clinical cases, orbitozygomatic craniotomy could be achieved in a short time, while preserving the structure of the orbital wall. A hollow at the temple was noted in 1 patient, cerebrospinal fluid leak occurred in 2 patients, and transient facial pain occurred in 1 patient; however, no other craniotomy-associated aesthetic or functional complications, including enophthalmos, were found in any of the 13 patients. CONCLUSIONS: With this modified technique, Zabramski's ideal orbitozygomatic craniotomy could be achieved easily with only minimal complications, while realizing all advantages of the technique.