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Background Understanding the complex anatomy of neurostructures is very important in various stages of medical education, from medical students to experienced neurosurgeons, and, ultimately, for the knowledge of human beings. Objective To develop an interactive computer graphics (CG) anatomic head model and present the current progress. Methods Based on the prior head 3-dimensional CG (3DCG) polygon model, 23 additional published papers and textbooks were consulted, and 2 neurosurgeons and 1 CG technician performed revision and additional polygon modeling. Three independent neurosurgeons scored the clear visibility of anatomic structures relevant to neurosurgical procedures (anterior petrosal and supracerebellar infratentorial approaches) in the integrated 3DCG model (i model) and patients' radiological images (PRIs) such as those obtained from computed tomography, magnetic resonance imaging, and angiography. Results The i model consisted of 1155 parts (.stl format), with a total of 313 763 375 polygons, including 10 times more information than the foundation model. The i model was able to illustrate complex and minute neuroanatomic structures that PRIs could not as well as extracranial structures such as paranasal sinuses. Our subjective analysis showed that the i model had better clear visibility scores than PRIs, particularly in minute nerves, vasculatures, and dural structures. Conclusion The i model more clearly illustrates minute anatomic structures than PRIs and uniquely illustrates nuclei and fibers that radiological images do not. The i model complements cadaveric dissection by increasing accessibility according to spatial, financial, ethical, and social aspects and can contribute to future medical education.

Chondroblastoma is a rare bone tumor, accounting for less than 2% of all bone tumors. Tumors arising in the temporal bone are extremely rare. A 66-year-old female was referred to the ENT department with hearing disturbance on the right side. Computed tomography showed a mass with a bony defect on the right squamous part of the temporal bone and glenoid fossa. T2-weighted magnetic imaging revealed a low signal mass in the right squamous part of the temporal bone. The pathological diagnosis from a biopsy specimen was chondroblastoma. Complete resection of the tumor and reconstructive surgery were performed by the surgical team, which included ENT, brain, oral maxillofacial, and plastic surgeons. Histopathological findings of the surgical specimen revealed that mononuclear cells and multinucleated giant cells proliferated with extensive hemosiderin deposition with a background of fibrous tissue and a cartilage-like myxoid matrix. Immunohistochemically, the nucleus and cytoplasm of mononuclear cells were positive for the anti-S-100 protein antibody. Therefore, the pathological diagnosis of chondroblastoma was confirmed. The patient has been followed up for 5 years and 7 months postoperatively without any severe clinical disturbance or sign of recurrence.

Pleomorphic xanthoastrocytomas (PXAs) are rare low-grade astrocytic tumors that typically present as superficial nodular cystic tumors of the cerebrum attached to the leptomeninx. Histologically, they are pleomorphic, hypercellular glial neoplasms. Despite the presence of microscopic pleomorphism, patients' postoperative prognosis is generally good. Anaplastic PXAs (APXAs) have a high mitotic index and patients with APXAs have a worse prognosis than patients with PXAs. Here, we report an autopsy case of APXA initially diagnosed as PXA. After gross total resection, the tumor recurred and was diagnosed as an APXA; thereafter, the patient died. An autopsy revealed that the tumor had relapsed at the primary site and had spread to the leptomeningeal space while concurrently invading the cerebrum including the periventricular area forming multifocal lesions. The histological findings of the autopsy were similar to those for epithelioid glioblastoma (EGBM) and small cell glioblastoma (SCGBM). In particular, the periventricular area with multifocal lesions was composed of SCGBM-like cells. It has been shown that multifocal lesions are frequently identified in patients with SCGBM. This is the first histopathologically confirmed case of APXA-related tumor presenting with periventricular extension and multifocal lesion formation. The periventricular extension might be a feature of PXAs and APXAs. However, suspected periventricular spread on imaging in past cases of PXAs and APXAs might instead represent the malignant transformation of these tumors to glioblastoma-like high-grade tumors, which often show SCGBM-like histological patterns.

Mechanical thrombectomy has been proposed to expand the treatment time window and enhance revascularization. However, it is unclear whether its use can be extended to patients with occlusions in acute aortic dissection, especially the thoracic aorta. A 55-year-old man underwent graft replacement for acute aortic dissection type A. On postoperative day 2, he developed stroke and computed tomography showed occlusion of the right middle cerebral artery. Mechanical thrombectomy was performed by transbrachial approach. Although successful recanalization was achieved, he suffered hemorrhagic stroke. Since there is no other effective treatment and the neurologic outcome with conservative management is poor, we consider mechanical thrombectomy to be a viable therapeutic option for the treatment of postoperative stroke in patients with acute aortic dissection type A. However, further study is warranted regarding the safety of this technique.

Endoscopic treatment for chronic subdural hematoma (CSDH) has been reported, but endoscopic findings of CSDH have not been thoroughly investigated. This study aimed to elucidate the relationship between endoscopic findings and CSDH recurrence. Furthermore, it examined the association between Nagahori’s histopathological staging of CSDH and outer membrane color. Here, we retrospectively analyzed the operative videos of 70 patients with CSDH. The endoscopic findings were investigated, and their correlations with CSDH recurrence, the reduction ratio of the midline shift, and hematoma thickness on day 30 after the operation were analyzed. The outer membrane was white in 21 cases, yellow in 25 cases, and red in 24 cases. CSDH recurred in three (4.2%) patients, all of whom had a white outer membrane (adjusted odds ratio, 18; 95% confidence interval, 1.6–20.6; P = 0.007). The other endoscopic findings were not significantly related to CSDH recurrence, extent of the reduction ratio of the midline shift, or hematoma thickness. The outer membrane colors of white, red, yellow, and white almost corresponded to the histopathological staging from type I to IV in order. Our findings suggest that a white outer membrane is a risk factor for recurrence; these colors may represent the extent of inflammation related to the evolution of CSDH estimated from the histopathological findings.

Background: Evaluating muscle mass and function among stroke patients is important. However, evaluating muscle volume and function is not easy due to the disturbances of consciousness and paresis. Temporal muscle thickness (TMT) has been introduced as a novel surrogate marker for muscle mass, function, and nutritional status. We herein performed a narrative literature review on temporal muscle and stroke to understand the current meaning of TMT in clinical stroke practice. Methods: The search was performed in PubMed, last updated in October 2021. Reports on temporal muscle morphomics and stroke-related diseases or clinical entities were collected. Results: Four studies reported on TMT and subarachnoid hemorrhage, two studies on intracerebral hemorrhage, two studies on ischemic stroke, two studies on standard TMT values, and two studies on nutritional status. TMT was reported as a prognostic factor for several diseases, a surrogate marker for skeletal muscle mass, and an indicator of nutritional status. Computed tomography, magnetic resonance imaging, and ultrasonography were used to measure TMT. Conclusions: TMT is gradually being used as a prognostic factor for stroke or a surrogate marker for skeletal muscle mass and nutritional status. The establishment of standard methods to measure TMT and large prospective studies to further investigate the relationship between TMT and diseases are needed.

These data present the 141 intracranial arterial branches' visibilities near the 72 cerebral aneurysms in postoperative 58 patients treated with titanium or cobalt-chromium-nickel-molybdenum (CCNM) alloy clips. The visibilities were evaluated using time-of-flight magnetic resonance angiography (TOF-MRA), pointwise encoding time reduction with radial acquisition (PETRA)-MRA, which uses MRA with ultrashort echo time (UTE-MRA) and subtraction technique between saturated and non-saturated images, and three-dimensional computed tomography angiography (3DCTA). We retrospectively acquired the data from the medical records of Suwa Red Cross Hospital. Each method's appearance was compared, and associations between visibility on PETRA-MRA, arterial diameter, clip numbers, clip shapes, clip materials, and amounts of hematoma were summarized. Our article on PETRA-MRA's usefulness for proximal and branched arteries evaluation after cerebral aneurysm clipping [1] was based on these data. This dataset would be useful for reference value for other neurosurgeons or radiologists for further analysis on PETRA-MRA and another UTE-MRA like SILENT-MRA after cerebral aneurysm clipping.

We report cases of acute subdural hematoma (ASDH) treated by endoscopic hematoma removal with a small craniotomy under local anesthesia. From 2015 to 2019, we retrospectively analyzed 15 ASDH patients who were 70 years or older and met our criteria for endoscopic treatment: (1) comorbidities indicated risks associated with a large craniotomy under general anesthesia; (2) decompressive craniectomy was unlikely; and (3) an enlarging hematoma was absent. We also performed a case-control study using the inverse probability weighting method to compare the 15 patients to 20 ASDH patients who were 70 years or older, met criteria (2) and (3), and were treated by craniotomy between 2012 and 2019. Among the 15 ASDH patients, the median age was 86 (range, 70-101) years, and fall was the common cause. The median Glasgow Coma Scale score on admission, operative time, stay time in the operation room, and bleeding amount were 8 (6-15), 91 (48-156) min, 120 (80-205) min, and 20 (5-400) mL, respectively. The extraction rates of all the hematomas exceeded 90%. No patients required conversion to craniotomy under general anesthesia. Three patients had favorable outcomes, and five died. The comparison with craniotomy revealed that the endoscopic procedure reduced the intraoperative bleeding amount, operative time, and stay time in the operation room (p

Objectives Endoscopic hematoma removal is widely performed for the treatment of intracerebral hemorrhage. We investigated the factors related to the prognosis of intracerebral hemorrhage after endoscopic hematoma removal. Materials and methods From 2013 to 2019, we retrospectively analyzed 75 consecutive patients with hypertensive intracerebral hemorrhage who underwent endoscopic hematoma removal. Their characteristics, including neurological symptoms, laboratory data, and radiological findings were investigated using univariate and multivariate analysis. Complications during hospitalization, Glasgow Coma Scale (GCS) score on day 7, and modified Rankin Scale (mRS) score at 6 months were considered as treatment outcomes. Results The mean age of the patients (33 women, 42 men) was 71.8 (36–95) years. Mean GCS scores at admission and on day 7 were 10.3 ± 3.2 and 11.7 ± 3.8, respectively. The mean mRS score at 6 months was 3.8 ± 1.6, and poor outcome (mRS score ranging from 3 to 6 at 6 months) in 53 patients. Rebleeding occurred in 4 patients, and other complications in 15 patients. Multivariate analysis revealed that older age, hematoma in the basal ganglia, lower total protein level, higher glucose level, and absence of neuronavigation were associated with poor outcomes. Of the 75 patients, 9 had cerebellar hemorrhages, and they had relatively favorable outcomes compared to those with supratentorial hemorrhages. Conclusion Several factors were related to the prognosis of intracerebral hemorrhage after endoscopic hematoma removal. Lower total protein level at admission and absence of neuronavigation were novel factors related to poor outcomes of endoscopic hematoma removal for intracerebral hemorrhage.

Contrast-enhanced computed tomography angiography is usually valuable for the evaluation of clipped cerebral aneurysm, but it has side effects of contrast medium. Time-of-flight magnetic resonance angiography (MRA) is a non-invasive and fast method. However, clip-induced artifact limits assessment of the artery in the vicinity of a clip. MRA with ultrashort echo time (TE) reduces metal artifact. We use MAGNETOM Aera 1.5T (SIEMENS, München, Germany) and perform pointwise encoding time reduction with radial acquisition (PETRA)-MRA using ultrashort TE for the assessment of the cerebral aneurysm after clipping. We, herein, presented two representative cases with a clipped aneurysm which could be evaluated by PETRA- MRA. Especially in one of them, the neck remnant was revealed by PETRA-MRA. PETRA-MRA can reduce the time and the invasiveness and may be helpful for the usual follow-up of the clipped aneurysm with the development of MRA technology in the future.

Background Hemodynamic factors, especially wall shear stress (WSS), are generally thought to play an important role in intracranial aneurysm (IA) formation. IAs frequently occur at bifurcation apices, where the vessels are exposed to the impact of WSS. Objective To elucidate the relationship between bifurcation geometry and WSS for IA formation. Methods Twenty-one bifurcation models varying in branch angles and branch diameters were made with 3-dimensional computer-aided design software. In all models, the value of maximum WSS (WSSMAX), the area of high WSS (AREA), and the magnitude of wall shear force over AREA ($| {{{\vec{F}}_w}} |$) were investigated by the steady-flow simulation of computational fluid dynamics. Results On the basis of statistical analysis, WSSMAX tended to be high when the bifurcation angle and/or branch diameter was small. AREA and $| {{{\vec{F}}_w}} |$ significantly increase as the bifurcation and/or the branch angle became larger. Conclusion The magnitude of WSS strongly correlated with bifurcation geometry. In addition to high WSS, AREA and $| {{{\vec{F}}_w}} |$ were thought to affect IA formation. Observed bifurcation geometry may predict IA formation. Large branch angles and small branch may increase the risk of IA formation.

Among pituitary adenomas, which are relatively common brain tumors, elements of ectopic, thyroid-stimulating hormone (TSH) secretion, and intratumoral calcification are unusual. Here, we present an extremely rare case of a calcified ectopic TSH-secreting pituitary adenoma arising from the pars tuberalis mimicking craniopharyngioma based on neuroimaging findings. To our knowledge, this is the first case report of calcified ectopic TSH-secreting pituitary adenoma without symptoms of excessive thyroid hormone secretion.

This data informs about the characteristics of elderly patients over 75 with subarachnoid hemorrhage whose World Federation of Neurosurgical Societies (WFNS) grade were I to III. We retrospectively collected data from medical records in our hospital regarding physiological symptoms, laboratory data, radiological data on admission, and outcomes at discharge. Our article entitled “Clinical characteristics of aneurysmal subarachnoid hemorrhage in the elderly over 75; would temporal muscle be a potential prognostic factor as an indicator of sarcopenia? [1]” was based on this data. Remarkably, this is the first dataset on temporal muscle thickness/area and other characteristics of elderly patients over 75 with subarachnoid hemorrhage whose WFNS grade were I to III. Temporal muscle thickness and area were large in the elderly patients with SAH whose outcome were favorable.

Objectives Age of patients with subarachnoid hemorrhage (SAH) is increasing. It is challenging to decide whether to perform aneurysm treatment and to predict their prognosis. We assumed that elderly patients with SAH who do not suffer from sarcopenia tend to have good outcomes. Temporal muscle thickness (TMT) and area (TMA) are useful indicators of sarcopenia. We investigated the clinical characteristics, including temporal muscle, in SAH patients over 75 years old. Patients and methods We retrospectively analyzed 49 SAH patients over 75 years old from 2014 to 2018, who accounted for 37% of the patients in all age group. The correlations between the clinical variables and the modified Rankin Scale (mRS) at discharge were analyzed. Results Of the all 49 SAH patients over 75 years old, premorbid mRS, WFNS grade, lymphocyte, aneurysm size, TMT, TMA, showed significant correlations with mRS at discharge. Men and the absence of hydrocephalus were correlated with favorable outcomes. Thirteen of the 24 patients over 75 years old whose WFNS grade were I to III but also who underwent aneurysm treatment had favorable outcomes (mRS 0–2), and their standardized TMT divided by height, by weight, and TMA divided by weight were significantly larger than that with poor outcomes. Conclusion Aneurysm intervention should be considered when patients over 75 years old do not suffer from sarcopenia. Temporal muscle would indicate premorbid mRS and be potentially useful to decide surgical indication and to predict outcome after aneurysm treatment in the elderly.

Background: Reliable prediction models of intracerebral hemorrhage (ICH) outcomes are needed for decision-making of the treatment. Statistically making such prediction models needs a large number of samples and time-consuming statistical analysis. Deep learning (DL), one of the artificial intelligence, is attractive, but there were no reports on DL-based functional outcome prediction models for ICH outcomes after surgery. We herein made a functional outcome prediction model using DLframework, Prediction One (Sony Network Communications Inc., Tokyo, Japan), and compared it to original ICH score, ICH Grading Scale, and FUNC score. Methods: We used 140 consecutive hypertensive ICH patients’ data in our hospital between 2012 and 2019. All patients were surgically treated. Modified Rankin Scale 0–3 at 6 months was defined as a favorable outcome. We randomly divided them into 100 patients training dataset and 40 patients validation dataset. Prediction One made the prediction model using the training dataset with 5-fold cross-validation. We calculated area under the curves (AUCs) regarding the outcome using the DL-based model, ICH score, ICH Grading Scale, and FUNC score. The AUCs were compared. Results: The model made by Prediction One using 64 variables had AUC of 0.997 in the training dataset and that of 0.884 in the validation dataset. These AUCs were superior to those derived from ICH score, ICH Grading Scale, and FUNC score. Conclusion: We easily and quickly made prediction models using Prediction One, even with a small single-center dataset. The accuracy of the DL-based model was superior to those of previous statistically calculated models.

Background: Skeletal muscle mass is an important factor for various diseases’ outcomes. As for its indicators, temporal muscle thickness (TMT) and temporal muscle area (TMA) on the head computed tomography are useful, and TMT and TMA were reported as potential prognostic factors for aneurysmal subarachnoid hemorrhage (SAH). We examined the clinical characteristics, including TMT and TMA, of SAH patients aged 75 or younger. Methods: We retrospectively investigated 127 SAH patients with all World Federation of Neurosurgical Societies (WFNS) grades and treated by clipping between 2009 and 2019. Clinical outcome was measured with the modified Rankin Scale (mRS) at 6 months, with favorable outcome defined as mRS 0–2. The associations between the clinical variables and the outcomes were analyzed. Results: The mean age was 60.6 (32–74) years, and 65% were women. The mean ± standard deviation of WFNS grade was 2.8 ± 1.4. TMT and TMA were larger in the favorable outcome group than the poor one. Multivariate analysis revealed that age, smoking, WFNS grade, and TMT or TMA were associated with favorable outcome. Receiver operating characteristic analysis found that the threshold of TMT was 4.9 mm in female and 6.7 mm in male, and that of TMA was 193 mm2 in female and 333 mm2 in male. Conclusion: The odds ratios for TMT and TMA related to clinical outcome were lower than for smoking and WFNS grade; however, on multivariate analysis they remained independent prognostic factors in SAH patients aged 75 or younger treated by clipping. Further studies are needed to confirm these findings.

These data present the characteristics of 148 intracerebral hemorrhage (ICH) patients surgically treated. We retrospectively collected data from the medical records of Suwa Red Cross Hospital, including neurological and physiological symptoms, laboratory data, radiological data on admission, complication rate, Glasgow Coma Scale scores on admission or postoperative day 7, and modified Rankin Scale scores at 6 months. Our two articles on the endoscopic hematoma removal and craniotomy for ICH were based on these data [ 1 , 2 ]. This dataset includes detailed laboratory data and radiological features, and it would be useful for reference value for other neurosurgeons or further analysis.

Background Revascularization of posterior circulation is essential in patients with severe bilateral vertebral artery (VA) stenosis despite administering maximal medical treatment, due to the high mortality of posterior circulation stroke. Case description We present a 69-year-old man with bilateral severe VA stenosis at the origins, treated with occipital artery (OA)-distal VA anastomosis. Conclusion Endovascular treatment and other surgical treatments, such as bypass grafting, are effective, but OA-VA anastomosis is a safe and effective procedure for revascularization of the posterior circulation.

A 67-year-old female with hypertension and impaired glucose tolerance was admitted to our hospital because of a typical acromegalic appearance, including large, thickened bulky hands and feet, and a large prominent forehead and tongue. She did not have a Cushingoid appearance, such as a moon-face, buffalo hump, purple striae or central obesity. The laboratory data revealed a serum GH level of 4.6 ng/mL and serum insulin-like growth factor-1 level of 811 ng/mL. The oral glucose tolerance test showed no suppression of the GH values. An endocrine examination showed a lack of circadian rhythmicity of ACTH and cortisol. Cortisol was not suppressed by a low dose of dexamethasone during the suppression test, but was suppressed by a high dose of dexamethasone. A radiological study revealed two isolated adenomas in the pituitary and a left adrenal tumor. These findings strongly suggested a diagnosis of acromegaly with subclinical Cushing's disease and a left adrenal incidentaloma. Transsphenoidal surgery was performed. Hematoxylin and eosin staining showed that the left and right pituitary adenomas were composed of basophilic and acidophilic cells, respectively. Immunohistochemical staining showed the left adenoma to be positive for ACTH and negative for GH. In contrast, the right adenoma was GH-positive and ACTH-negative. This is a rare case of independent double pituitary adenomas with distinct hormonal features. We also provide a review of the previously reported cases of double pituitary adenomas and discuss the etiology of these tumors.

Object The aim of this study was to evaluate cerebral aneurysm clips, and to know in more detail the characteristics of currently available clips in the 3-T magnetic field. Methods According to the protocol recommended by the American Society for Testing and Materials (ASTM), the authors conducted quantitative evaluation for displacement force and qualitative evaluation for torque in 52 aneurysm clips and 48 samples of raw materials in the 3-T environment. Results The largest displacement force occurred near the bore opening, and the force was directed to the isocenter. Deflection angles of all objects in this study were within 45°. The translational force in the peripheral position in the bore was larger than that in the center, and the translational force in the magnetic field was proportional to the weight of the objects. The proportion coefficients varied depending on the metallic materials. In the titanium alloy, the deflection angle was also detected to be approximately 2°, although no response was observed in titanium in a previous report. This behavior was similar to that of the Elgiloy and Phynox materials in the 1.5-T environment. No difference was observed among the groups of shapes (straight, bent, and fenestrated). The amount of torque that occurred was dependent on the clip's or material's loop and bent shape. The torque on the titanium was perpendicular to the torque on the other materials (which was perpendicular to the magnetic field). Conclusions Care must be taken with patients near the bore opening while moving them to the center of the magnet's bore on the MR imaging table. Although all the clips examined in this study met the ASTM requirements, the titanium alloy clips are preferable in the 3-T environment for safety's sake. Suitably sized clips should be selected for the aneurysm size, because the translational force increases proportionally to the object's weight.

The purpose of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured anterior (dorsal) paraclinoid aneurysms. Anterior paraclinoid aneurysms are defined as aneurysms arising from the anterolateral wall of the proximal internal carotid artery without any relationship to an arterial branch. Between 1991 and 2008, a total of 159 patients with 169 paraclinoid aneurysms were treated at the Shinshu University Hospital and its affiliated hospitals. A retrospective analysis was carried out using charts, operation records, operation videos, and neuroimagings. Twenty six patients had anterior paraclinoid aneurysm. Six patients presented with SAH. Three aneurysms were saccular and the others were blister-like aneurysms based on operative findings. Neck laceration or premature rupture frequently happened during the clipping surgery even though the aneurysm was saccular type. The treatment of a ruptured anterior paraclinoid aneurysm is quite difficult. Trapping and bypass would be recommended for such fragile aneurysms., Article, NEUROSURGICAL REVIEW. 34(1):49-54 (2011)

OBJECTIVE: We sought to investigate the three-dimensional structure of the white matter of the brain by means of the fiber-dissection technique and diffusion-tensor magnetic resonance imaging to assess the usefulness of the combination of both techniques, compare their results, and review the potential functional role of fiber tracts. METHODS: Fifteen formalin-fixed human hemispheres were dissected according to Klingler’s fiber-dissection technique with the aid of 6 to 40 magnification. Threedimensional anatomic images were created with the use of specific software. Two hundred patients with neurological symptoms and five healthy volunteers were studied with diffusion-tensor magnetic resonance imaging (3 T) and tractographic reconstruction. RESULTS: The most important association, projection, and commissural fasciculi were identified anatomically and radiologically. Analysis of their localization, configuration, and trajectory was enhanced by the combination of both techniques. Threedimensional anatomic reconstructions provided a better perception of the spatial relationships among the white matter tracts. Tractographic reconstructions allowed for inspection of the relationships between the tracts as well as between the tracts and the intracerebral lesions. The combination of topographical anatomic studies of human fiber tracts and neuroanatomic research in experimental animals, with data from the clinicoradiological analysis of human white matter lesions and intraoperative subcortical stimulation, aided in establishing the potential functional role of the tracts. CONCLUSION: The fiber-dissection and diffusion-tensor magnetic resonance imaging techniques are reciprocally enriched not only in their application to the study of the complex intrinsic architecture of the brain, but also in their practical use for diagnosis and surgical planning.

Object The goal in this study was to examine the microsurgical and tractographic anatomy of the claustrum and its projection fibers, and to analyze the functional and surgical implications of the findings. Methods Fifteen formalin-fixed human brain hemispheres were dissected using the Klingler fiber dissection technique, with the aid of an operating microscope at × 6–40 magnification. Magnetic resonance imaging studies of 5 normal brains were analyzed using diffusion tensor (DT) imaging–based tractography software. Results Both the claustrum and external capsule have 2 parts: dorsal and ventral. The dorsal part of the external capsule is mainly composed of the claustrocortical fibers that converge into the gray matter of the dorsal claustrum. Results of the tractography studies coincided with the fiber dissection findings and showed that the claustrocortical fibers connect the claustrum with the superior frontal, precentral, postcentral, and posterior parietal cortices, and are topographically organized. The ventral part of the external capsule is formed by the uncinate and inferior occipitofrontal fascicles, which traverse the ventral part of the claustrum, connecting the orbitofrontal and prefrontal cortex with the amygdaloid, temporal, and occipital cortices. The relationship between the insular surface and the underlying fiber tracts, and between the medial lower surface of the claustrum and the lateral lenticulostriate arteries is described. Conclusions The combination of the fiber dissection technique and DT imaging–based tractography supports the presence of the claustrocortical system as an integrative network in humans and offers the potential to aid in understanding the diffusion of gliomas in the insula and other areas of the brain.

OBJECTIVE: Burn injuries associated with excessive heating of medical metallic devices have been reported, but a definite mechanism for magnetic resonance imaging-induced heating remains unresolved. The aim of this study is to evaluate temperature elevation of metallic wires, aneurysm clips, and clips attached to metallic wires under 3.0-T magnetic resonance imaging. METHODS: The temperature of the metallic wires, the aneurysm clips, and the clips attached to the metallic wires was measured with a fiber optic thermometer sensor system. RESULTS: Although the specific absorption rate was less than that observed during standard use, the temperature rapidly increased in the metallic wire. Furthermore, temperature elevation was observed when the clips were attached to metallic wires. On the other hand, not all clips showed obvious temperature elevation when they were placed alone in a 3.0-T magnetic resonance imaging environment. CONCLUSION: Aneurysm clips, when placed alone in a 3.0-T magnetic resonance imaging environment, are confirmed to be safe during temperature elevation.

Objective The course of the lesser petrosal nerve is not well understood and may be confused with the course of the greater petrosal nerve during middle fossa surgery. The objective was to examine the course of the lesser petrosal nerve along the floor of the middle cranial fossa from the region of the geniculate ganglion to its outlet from the skull base. There are no studies focused on the course of this nerve in relationship to the floor of the middle cranial fossa. Methods Twenty middle fossae from adult cadaveric specimens were examined using 3 to 40x magnification. Results The lesser petrosal nerve was partially exposed on the floor of the middle fossa without drilling in 75% of the middle fossae and totally covered by thin bone in 25%. It crossed the floor anterior to the greater petrosal nerve and exited the middle fossa through the canaliculus innominatus in 14 cases, foramen spinosum in 3 cases, and the sphenopetrosal suture in 3 cases. The course of the lesser petrosal nerve has been shown in textbooks to be parallel to the greater petrosal nerve. However, the lesser and greater petrosal nerves diverged in the area medial to the geniculate ganglion in 90% of middle fossae with the angle of divergence averaging 11.6 degrees. The course of the lesser petrosal nerve was divided into three patterns based on the site of confluence of the three bundles of fibers forming the nerve. Conclusion The relationships of the lesser petrosal nerve in the middle cranial fossa have been described. An understanding of these relationships will reduce the likelihood of it being confused with the greater petrosal nerve during surgical approaches to the middle fossa.

OBJECTIVE: The goal was to develop an interactive three-dimensional (3-D) computerized anatomic model of the skull base for teaching microneurosurgical anatomy and for operative planning. METHODS: The 3-D model was constructed using commercially available software (Maya 6.0 Unlimited; Alias Systems Corp., Delaware, MD), a personal computer, four cranial specimens, and six dry bones. Photographs from at least two angles of the superior and lateral views were imported to the 3-D software. Many photographs were needed to produce the model in anatomically complex areas. Careful dissection was needed to expose important structures in the two views. Landmarks, including foramen, bone, and dura mater, were used as reference points. RESULTS: The 3-D model of the skull base and related structures was constructed using more than 300,000 remodeled polygons. The model can be viewed from any angle. It can be rotated 360 degrees in any plane using any structure as the focal point of rotation. The model can be reduced or enlarged using the zoom function. Variable transparencies could be assigned to any structures so that the structures at any level can be seen. Anatomic labels can be attached to the structures in the 3-D model for educational purposes. CONCLUSION: This computer-generated 3-D model can be observed and studied repeatedly without the time limitations and stresses imposed by surgery. This model may offer the potential to create interactive surgical exercises useful in evaluating multiple surgical routes to specific target areas in the skull base.

This study was designed to clarify the various factors associated with the poor prognosis of the dorsal aneurysm of the internal carotid artery. Three hundred sixty-five aneurysms diagnosed by angiography were registered from 171 institutes in Japan by questionnaire between January 2001 and December 2003. The average age at diagnosis was 53.8 years among 105 men and 233 women patients. Sixty-eight aneurysms were located in C1, 74 in C1-2 and 213 in C2. Three hundred thirty-nine aneurysms obtained Glasgow outcome score (GOS) of all 365 aneurysms were extracted and classified into group A (Good Recovery (GR), Moderate Disability (MD)) and group B (Severe Disability (SD), Vegetative State (VS), Dead (D)) for analysing various factors. Poor prognostic factors were assessed by single variate analysis. Significant prognostic factors are rupture as onset (Odds ratio [OR] 9.9850), intraoperative bleeding (OR 6.3979), postoperative regrowth of the aneurysm (OR 5.8586), preoperative rebleeding (OR 5.1278), postoperative bleeding (OR 4.6397), Hunt-Kosnik grade greater than 3 (OR 4.5247), suspicion of dissecting aneurysm on angiogram (OR 3.5023), World Federation of Neurosurgical Societies (WFNS) grade greater than 3 (OR 3.2734), diagnosis as dissection in the operative field (OR 3.2296), thin aneurysm neck (OR 3.0252), thin aneurysm dome (OR 2.8794), temporary occlusion of the cervical carotid artery (OR 2.8667), and Fisher group greater than 3 (OR 2.3564). No significant differences were observed in the history, including hypertension, age, sex, size of an aneurysm dome and neck, presence of other aneurysms for the poor outcome. Observation therapy, i.e., no treatment, was correlated with poor outcome. Any perioperative bleedings strongly correlated with poor outcome. We should pay more attention to patients with a regrowing, thin walled aneurysm than to those with a larger aneurysm. Since the conservative treatment does not result in the good outcome, we need to treat those patients in the early stage.

We report five patients with odontoid invagination, in which the odontoid process bulges upward into the foramen magnum and compresses the brainstem without deformity of the occipital bone. Two patients had a craniovertebral abnormality associated with Chiari malformation without instability of the craniovertebral junction (stable odontoid invagination). The other three patients had dislocation of the craniovertebral junction due to iatrogenic destruction of the occipital condyle, rheumatoid arthritis or an anomaly of C2 (unstable odontoid invagination). Patients with stable odontoid invagination underwent a transoral odontoidectomy followed by occipitocervical fixation. Those with unstable odontoid invagination underwent cervical traction followed by posterior fixation in reducible cases, while in irreducible cases odontoidectomy with subsequent occipitocervical fixation was performed. Decompression of the neuraxis together with symptomatic improvement was achieved in all patients and none became unstable or developed new symptoms during follow-up ranging from 3 to 15 years.

Background As far as we know, 6 cases of extracranial (including craniocervical junction) intradural aneurysms of the posterior inferior cerebellar artery have been previously reported. However, preoperative detailed evaluation of the origin site and a course of the posterior inferior cerebellar artery by means of angiography were not reported in previous papers. Case description We report a rare case of aneurysm of the posterior inferior cerebellar artery, which originated extradurally from the right vertebral artery. A 69-year-old woman experienced a sudden headache 16 years ago and a computed tomography scan showed a subarachnoid hemorrhage around the midbrain. Four-vessel cerebral angiography, however, failed to disclose a source of the hemorrhage. Magnetic resonance angiography incidentally revealed an aneurysm at the craniocervical junction 16 years after the subarachnoid hemorrhage. The aneurysm was exposed and clipped via a suboccipital route. At surgery, it was of no use to apply a temporary clip on the intradural segment of the vertebral artery, because the posterior inferior cerebellar artery was found to enter the intradural space separately from the vertebral artery. The blood flow to such an aneurysm cannot be stopped with this procedure. Conclusion Careful neuroimaging study is essential for the accurate diagnosis and successful treatment of such a rare aneurysm.

The NeuRobot, telecontrolled micromanipulator system, having a rigid neuroendoscope and three robot arms, has been developed for less invasive and telecontrolled neurosurgery. It has a capability of sophisticated surgical procedures through a small window of 10-mm width. In this paper, bipolar coagulator system, sterilization, and experience of clinical application are reported. The NeuRobot will become a promising neurosurgical tool for less invasive neurosurgery.

✓ Three-dimensional (3D) neuroimages are generally considered useful for neurosurgical practice. Nevertheless, neuroimaging modalities such as 3D digital subtraction angiography and 3D computerized tomography angiography are still insufficient because the resulting images fail to delineate neural structures. Complex neurosurgical procedures are mostly performed in the cerebrospinal fluid (CSF) space of the basal cistern, where vessels and neural structures are present along with the lesion. The magnetic resonance (MR) imaging—derived 3D constructive interference in steady-state (CISS) imaging displays the margin between the CSF and neural structures, vessels, and dura mater in detail, in a two-dimensional fashion. The authors know that volume-rendered 3D CISS images would be more useful for surgery than conventional ones. Although the usefulness of “virtual MR image endoscopy” was reported previously, the endoscopic view is different from the operative field because of the perspective being emphasized. Therefore, to simulate surgical views, the authors made 3D neuroimages from a 3D CISS MR sequence by using an advanced computer workstation. After generating volume images, a cutting method was used in the desired plane to visualize the lesion with reference to a multiplanar reformatted image. The authors call these “real” 3D CISS images, and they are more comparable to the operative field. This newly developed method of producing a real 3D CISS image was used in 30 cases and contributed to the understanding of the relationship between a lesion and surrounding structures before attempting neurosurgical procedures, with minimal invasiveness to the patient.

Object. Surgical cure can be achieved in pituitary adenomas when they are completely removed. It is controversial whether postoperative radiation therapy should be given to prevent recurrence, and whether an early reoperation should be performed for residual adenomas, because we have little information about the natural history of postoperative residual adenomas. Methods. The residual tumor volume was serially measured in 40 nonfunctioning pituitary adenomas (NFPAs) and the tumor volume doubling time (TVDT) was calculated. Correlations between the patients' age, tumor volume, log TVDT, and MIB-1 index were examined. Other factors including the patient's sex, cavernous sinus (CS) invasion by the tumor, or presence of an intratumoral cyst were analyzed to assess their influence on the TVDT. Values are expressed as the means ± standard deviations. Thirty-eight adenomas increased in volume and two decreased during a follow-up period ranging from 4 to 141 months (mean 52.5 months). Exponentially linear tumor growth was observed in the 38 growing adenomas regardless of the residual tumor volume, with the TVDT ranging from 506 to 5378 days (mean 1836 days). The patients' age was 57.1 ± 15.7 years (range 15–79 years), the tumor volume at the beginning of the magnetic resonance imaging observation period was 2.5 ± 2.2 cm3 (range 0.07–14.5 cm3), and the MIB-1 index was 0.73 ± 0.68% (range 0.1–2.9%). There was a correlation between the log TVDT and patient age (R = 0.73), an inverse correlation between the log TVDT and MIB-1 index (r = −0.49), and an inverse correlation between the MIB-1 index and patient age (r = −0.61). A significant difference (p = 0.0001) was noted between the TVDT (1106 days) in the 19 patients younger than 61 years of age and the TVDT (2566 days) in the 19 patients who were 61 years of age or older. There was also a significant difference (p = 0.0002) between the age (50.8 ± 15.3 years) of the patients with rapidly growing tumors (TVDT < 1836 days, 24 patients) and the age (69.1 ± 7.6 years) of the patients with slowly growing tumors (TVDT > 1836 days, 14 patients). Other factors including the patients' sex, CS invasion, and intratumoral cyst formation did not affect the TVDT of residual NFPAs. Conclusions. The tumor growth rate of residual NFPAs is strongly influenced by the patient's age. The TVDT in elderly patients is much longer than that previously reported. Treatment strategies that take into consideration the natural history of residual adenomas should be established especially in the elderly population.

OBJECTIVE AND IMPORTANCE Precise preoperative evaluation is especially important when internal carotid artery aneurysms in the paraclinoid region are clipped, because these vascular structures are located in close proximity to various important structures such as the optic nerve and anterior clinoid process. We report a new method for “simultaneously” describing the interrelationships among the aneurysm, internal carotid artery, optic nerve, and bony structures with three-dimensional contrast medium-enhanced computed tomographic (3-D CMECT) cisternography. METHODS Informed consent was obtained from the patient. An 8-ml injection of iotrolan (Isovist; Schering, Berlin, Germany) (240 mg I/ml) was administered into the lumbar intrathecal space. A computed tomographic scan of the head was obtained 2 hours later with a multislice Asteion computed tomographic scanner (Toshiba, Inc., Tokyo, Japan). An Alatoview workstation (Silicon Graphics, Mountain View, CA) was used to reconstruct the three-dimensional images. RESULTS These images, as generated by 3-D CMECT cisternography, were found to accurately demonstrate the interrelationships of the internal carotid artery, aneurysm, and surrounding structures preoperatively. The findings obtained from these images proved to be quite similar to the intraoperative findings. 3-D CMECT cisternography clarified whether the paraclinoid aneurysm was intradural or extradural. CONCLUSION 3-D CMECT cisternography was found to provide a useful means for preoperative evaluation of lesions in the paraclinoid area.

Objective Microneurosurgery can be performed less invasively with the recent advances in neuronavigation and neuroendoscopy. For even less invasive microneurosurgery, we have developed a telecontrolled micromanipulator system. Methods The NeuRobot telecontrolled micromanipulator system was developed. With the use of this system, surgical simulations were performed with a human cadaveric head. Results The system consists of four main parts, i.e., a micromanipulator (slave manipulator), a manipulator-supporting device, an operation-input device (master manipulator), and a three-dimensional display monitor. Three 1-mm forceps and a three-dimensional endoscope, which could be remotely controlled with three degrees of freedom (rotation, neck swinging, and forward/backward motion), were installed in the slave manipulator. All surgical procedures were accurately performed with this system. Conclusion The use of telecontrolled manipulator systems in neurosurgery is very promising, and we are convinced that this system will facilitate more accurate, less invasive microneurosurgery. The details of the NeuRobot system and preliminary results are presented.

Background Many approaches for clipping anterior communicating artery (ACoA) aneurysms are reported in the literature. We describe here a new approach called "low anterior interhemispheric approach" for clipping of ACoA aneurysms. Materials and methods A low anterior interhemispheric approach utilizing a unilateral frontal craniotomy flap with minimal unilateral frontal lobe retraction was used in treating four patients harboring an unruptured ACoA aneurysm. The approach axis is directed to the ACoA area itself with minimal exposure to the anterior cerebral vessels. Findings In all patients, complete neck clipping was possible with minimal brain retraction, without vascular damage and preserved olfaction. Interpretation This approach is preferred on anatomical grounds for cases of unruptured small and medium sized ACoA aneurysms projecting anteriorly or posteriorly because the anterior communicating artery complex area can be fully visualized with minimal manipulation of the frontal lobes and anterior cerebral arteries.