Local and systemic factors associated with quantitative stiffness of carotid plaque.

PURPOSE: Plaque stiffness in carotid artery stenosis is a clinically important factor involved in the development of stroke and surgical complications. The purpose of this study was to clarify which local and systemic factors are associated with the quantitatively measured stiffness of plaque. METHODS: The subjects were 104 consecutive patients who underwent carotid endarterectomy at our institution. To measure quantitative stiffness of plaque, we used an industrial hard meter in the operating room within 1 h after removal of plaque. Local factors related to carotid plaque hardness were evaluated, including maximum intima-media thickness (max IMT), degree of stenosis using the European Carotid Surgery Trial (ECST), presence of ulceration or calcification, and echo brightness on preoperative carotid ultrasound. The degree of stenosis was also evaluated using the North American Symptomatic Carotid Endarterectomy Trial method in digital subtraction angiography. Age, sex, and presence or absence of hypertension, diabetes, and dyslipidemia (low-density lipoprotein cholesterol and triglyceride [TG] levels) served as systemic factors and were compared with the quantitative stiffness of carotid plaque. RESULTS: In multivariate analysis, ECST stenosis degree, calcification, and IMT max as local factors affected plaque stiffness. As a systemic factor, plaque stiffness was statistically significantly negatively correlated with TG values in multivariate analysis (p < 0.05). CONCLUSION: The quantitative stiffness of the plaque was negatively correlated with TG levels as a systemic factor in addition to local factors. This might suggest that reducing high TG levels is associated with plaque stabilization.

Differentiation between Anterior and Posterior Roots Using Compound Muscle Action Potential in Intradural Extramedullary Spinal Tumor Surgery.

This study aims to determine the cutoff values for the compound muscle action potential (CMAP) stimulus in anatomically identified anterior (motor nerve) and posterior roots (sensory nerve) during cervical intradural extramedullary tumor surgery. The connection between CMAP data from nerve roots and postoperative neurological symptoms in thoracolumbar tumors was compared with data from cervical lesions. The participants of the study included 22 patients with intradural extramedullary spinal tumors (116 nerve roots). The lowest stimulation intensity to the nerve root at which muscle contraction occurs was defined as the minimal activation intensity (MAI) in the CMAP. In cervical tumors, the MAI was measured after differentiating between the anterior and posterior roots based on the anatomical placement of the dentate ligament and nerve roots. The MAIs for 20 anterior roots in eight cervical tumors were between 0.1 and 0.3 mA, whereas those for 19 posterior roots were between 0.4 and 2.0 mA. The cutoff was <0.4 mA for both the anterior and posterior roots, and sensitivity and specificity were both 100%. In thoracolumbar tumors, the nerve root was severed in 12 of 14 cases. All MAIs were determined to be at the dorsal roots as their scores were higher than the cutoff and did not indicate motor deficits. The MAIs of the anatomically identified anterior and posterior root CMAPs were found to have a cutoff value of <0.4 mA in the cervical lesions. Similar MAI cutoffs were also applicable to thoracolumbar lesions. Thus, CMAP may be useful in detecting anterior and posterior roots in spinal tumor surgery.

Relationship Between Quantitative Tumor Consistency and Pathological Factors in Intracranial Meningioma.

BACKGROUND: The consistency of intracranial meningiomas is an important clinical factor because it affects the success of surgical resection. This study aimed at identifying and quantitatively measuring pathological factors that contribute to the consistency of meningiomas. Furthermore, we investigated the relationship between these factors and preoperative neuroradiological imaging. METHODS: We analyzed 42 intracranial meningioma specimens, which had been removed at our institution between October 2012 and March 2018. Consistency was measured quantitatively after resection using an industrial stiffness meter. For pathological evaluation, we quantitatively measured the collagen-fiber content through binarization of images of Azan-Mallory-stained section. We assessed calcification and necrosis semi-quantitatively using images acquired of Hematoxylin and Eosin stained samples. The relationship between collagen-fiber content rate and imaging findings was examined. RESULTS: The content of collagen fibers significantly positively correlated with meningioma consistency (p < 0.0001). Collagen-fiber content was significantly higher in low- and iso-intensity regions compared with high-intensity regions on the magnetic resonance T2-weighted images (p = 0.0148 and p = 0.0394, respectively). Calcification and necrosis showed no correlation with tumor consistency. CONCLUSIONS: The quantitative hardness of intracranial meningiomas positively correlated with collagen-fiber content; thus, the amount of collagen fibers may be a factor that determines the hardness of intracranial meningiomas. Our results demonstrate that T2-weighted images reflect the collagen-fiber content and are useful for estimating tumor consistency preoperatively and non-invasively.

Brain Diseases and Fall-Related Surgery in Older Persons.

BACKGROUND: It is known that age-related brain symptoms (gait difficulty and dementia) increase the likelihood of fall-related surgery. In contrast, it is not known which types of brain disease underlie such symptoms most. OBJECTIVE: The aim of this study was to correlate brain diseases with the types of surgeries performed at our hospital for patients who had fallen. METHODS: This was a retrospective study at a multifaculty university hospital in Japan, with a 12-month recruiting period, a follow-up period of 3.0 ± 2.5 weeks, and ≥1×/week visits. We assembled a neurogeriatric team to diagnose brain diseases with the use of brain imaging to the extent possible and correlated the diagnoses with types of fall-related surgery. RESULTS: Fall-related surgery was conducted by the orthopedics (OP) and neurosurgery (NS) faculties (total n = 124) at a ratio of about 2 to 1. The underlying brain diseases differed by faculty; for OP, surgery was most commonly performed in patients with a combination of white matter disease (WMD) and Alzheimer's disease (AD) (79%) followed by dementia with Lewy bodies. In contrast, for NS, the most common surgery was for patients with alcoholism (50%) followed by a combination of WMD and AD. CONCLUSION: Fall-related surgery was performed by the OP and NS faculties at a 2 to 1 ratio. The major underlying brain diseases were a combination of WMD and AD (79%) for OP and alcoholism (50%) for NS.

Repeated intracranial empyema following cranioplasty in a patient with atopic dermatitis: a case report.

BACKGROUND: Atopic dermatitis is a chronic inflammatory skin disease associated with pruritus. Skin affected by atopic dermatitis not only shows a high percentage of Staphylococcus aureus colonization, but corneal barrier dysfunction is also known to occur. It is considered a risk factor for bacterial infections in various areas of the body. However, the relationship between atopic dermatitis and bacterial infection following neurological surgery has not yet been reported. Here, we present a case of atopic dermatitis in which the surgical site became infected twice and finally resolved only after the atopic dermatitis was treated. CASE PRESENTATION: A 50-year-old Japanese woman with atopic dermatitis underwent cerebral aneurysm clipping to prevent impending rupture. Postoperatively, she developed repeated epidural empyema following titanium cranioplasty. As a result of atopic dermatitis treatment with oral antiallergy medicines and external heparinoids, postoperative infection was suppressed by using an absorbable plastic plate for cranioplasty. The patient's postoperative course was uneventful for 16 months. CONCLUSIONS: Atopic dermatitis is likely to cause surgical-site infection in neurosurgical procedures, and the use of a metal implant could promote the development of surgical-site infection in patients with dermatitis.

Utility of Schwann/2E and Sox10 in distinguishing CD57-negative olfactory groove schwannoma from olfactory ensheathing cell tumor: A case report and review of the literature.

We herein report a patient who was diagnosed as having olfactory groove schwannoma (OGS) which was negative for CD57 (Leu7) but positive for Schwann/2E and Sox10. A 13-year-old female with a chief complaint of headache was referred to our department due to a tumor lesion in the anterior skull base identified by magnetic resonance imaging (MRI). At the first visit, she did not exhibit altered consciousness, motor palsy, anosmia, seizures, or café au lait spots. On contrast-enhanced computed tomography (CT), a heterogeneously enhanced tumor, 50 × 45 × 50 mm in size, was observed at the anterior skull base. The left cribriform plate was thinner on bone window CT. The tumor exhibited strong, heterogeneous gadolinium enhancement on MRI as well. Slight tumor staining was observed by angiography of the left internal carotid artery but not the left external carotid artery. The patient was preoperatively diagnosed as having meningioma and underwent gross tumor resection via the basal interhemispheric approach. The tumor was strongly positive for S-100 protein and negative for epithelial membrane antigen and CD57 by immunostaining. The tumor was positive for both Schwann/2E and Sox10, which aided in the differential diagnosis between OGSs and olfactory ensheathing cell (OEC) tumors, and the definitive diagnosis was OGS. The assessment of immunoreactivities for Schwann/2E and Sox10 might be necessary to differentiate CD57-negative Schwannomas from OEC tumors.

Comparison of quantitative measurements of central nervous system tumour consistency and the associated preoperative imaging findings.

Purpose: Central nervous system (CNS) tumour consistency is one of the factors determining the difficulty of surgery for such lesions. We measured the consistency of surgically excised CNS tumour specimens using a hardness meter. The purpose of this study was to identify imaging parameters that reflect tumour consistency by comparing preoperative imaging findings with CNS tumour consistency measurements. Material and methods: Of 175 consecutive patients with CNS tumours who underwent surgery at our hospital between October 2012 and October 2018, 127 were included in this study (those whose specimens were difficult to measure were excluded). CNS tumour consistency was measured immediately after surgical excision using a hardness meter and compared with preoperative T1-weighted, T2-weighted (T2WI), fluid attenuated inversion recovery (FLAIR), diffusion-weighted imaging, gadolinium-enhanced magnetic resonance imaging, plain computed tomography (CT), and contrast-enhanced CT findings. Tumour consistency was also subjectively classified by the surgeon into soft, hard, or very hard. Results: The intracranial meningiomas were harder than the metastatic tumours and gliomas (p = 0.03 and p = 0.03, respectively). Among the intracranial meningiomas, the tumours that exhibited high intensity on T2WI were softer than those that displayed isointensity or low intensity (p < 0.001 and p < 0.001, respectively), and the isointense tumours were softer than the low intensity tumours (p = 0.02). Among the metastatic tumours, the tumours that exhibited high intensity on T2WI were softer than those that displayed isointensity or low intensity (p < 0.001 and p < 0.001, respectively). Among the intracranial meningiomas and metastatic tumours, significant correlations were detected between the T2WI findings and subjective tumour consistency according to the surgeon or quantitative tumour consistency (p = 0.01 and p = 0.03, respectively). Conclusions: The preoperative T2WI findings of intracranial meningiomas and metastatic tumours were significantly correlated with quantitatively measured tumour consistency and subjectively evaluated tumour consistency. Therefore, we concluded that T2WI findings are useful for preoperatively predicting the consistency of such tumours.

Three-Dimensional Printed Model for Surgical Simulation of Combined Transpetrosal Approach.

BACKGROUND: The combined transpetrosal approach is a complicated skull base surgery with a high degree of difficulty. Herein, we made a 3-dimensional (3D) printed petrous bone with color-coded anatomic sites and evaluated its usefulness as a model to practice drilling associated with combined transpetrosal surgery. METHODS: To design a 3D model of the petrous bone, we chose a representative epidermoid petroclival tumor case who underwent combined transpetrosal surgery at our hospital. A 3D image of the petrous bone embedded with color-coded anatomic sites, including cranial nerves, brainstem, and internal carotid and vertebrobasilar arteries, was created based on preoperative computed tomography scan, magnetic resonance, and digital subtraction angiography images and was then 3D printed. Thirteen neurosurgeons from our department evaluated the anatomic reproducibility and estimated distance between each anatomic site of the 3D image and model and the usefulness of the model for drilling practice. RESULTS: The anatomic reproducibility of both the 3D image and model was high, and the 3D model was considered good for drilling practice (P < 0.05). The error in the estimated distance between anatomic sites in the 3D model was significantly smaller than that of the 3D image (P < 0.0001). CONCLUSIONS: These results indicate that our 3D printed model is very useful for practice with craniotomy and petrosectomy drilling, necessary in the combined transpetrosal approach.

[Diffuse Astrocytoma with Pilomyxoid Features Presenting as Intratumoral Hemorrhage:A Case Report].

Hemorrhagic low-grade glioma(LGG)without malignant transformation is rare, accounting for less than 1% of cases. To the best of our knowledge, hemorrhagic LGG with an arteriovenous(AV)shunt has not been reported. We report the case of 17-year-old man with LGG with an AV shunt. He presented to our hospital with seizure. Computed tomography(CT)demonstrated a hypodense lesion with mass effect in the right frontal lobe. T1-weighted images(WI)and T2WI on magnetic resonance imaging(MRI)revealed acute-onset hemorrhage in the right frontal lobe. Furthermore, a ring-enhancing lesion was noted on gadolinium(Gd)-DTPA T1WI, and an AV shunt was found in the same region on angiography. Gross total tumor resection was performed. The pathological diagnosis was diffuse astrocytoma with pilomyxoid features(WHO grade II). Without adjuvant therapy, no residual tumor was found on MRI at the 6-year follow-up examination. We treated a case of hemorrhagic LGG with an AV shunt. Intratumoral hemorrhage in LGG may occur and should be considered for the differential diagnosis.

[Acute Changes in the Computed Tomography Findings of Mucocele Combined with Pituitary Adenoma:A Case Report].

INTRODUCTION: We report a rare case in which a pituitary tumor co-occurred with a giant mucocele. The mucocele's computed tomography(CT)values fell markedly when it collapsed, and we report the associated considerations. CASE: This case involved a 42-year-old male patient. For 20 years, his visual acuity had progressively declined, and it suddenly rapidly worsened over a month. Cranial CT revealed a massive tumor in the sphenoid sinus and a pituitary tumor. A region of high absorption extended from the paranasal sinus to the skull base. Two days after the patient's initial presentation, he experienced a sudden loss of vision. Therefore, we performed an urgent re-examination. The CT value of the paranasal lesion was found to have sharply declined. The sinus lesion was diagnosed as a mucocele. Emergent endoscopic surgery was performed. Actinomyces meyeri was detected in the samples cultures. DISCUSSION: The causes of mucocele exhibiting abnormally high signal intensity on CT include the accumulation of hemosiderin due to repeated bleeding in the cyst. Furthermore, we inferred that the Actinomyces meyeri had been taking up metallic elements in vivo for a long time. The marked reduction in the lesion's CT value was considered to have been due to the destruction of the mucocele. The contents of the mucocele flowed out and were replaced with newly produced mucus, which exhibits low absorption values. CONCLUSION: We treated a patient with a giant mucocele involving distraction of the frontal base and a pituitary adenoma. In such cases, surgery should be performed when visual acuity deteriorates suddenly.

[A Case of Male Breast Cancer with Brain Metastasis 24 Years after a Mastectomy].

Male breast cancer accounts for less than 1.0% of all breast cancer cases, and its brain metastasis is very rare. We encountered a male patient in whom brain metastasis occurred more than 20 years after the development of breast cancer. The patient was a 78-year-old male who underwent surgery for right breast cancer 24 years ago. Nausea and anorexia had appeared 2 months earlier, and the patient was referred to our department because a brain tumor was suspected on MRI. A 4×4-cm tumorous lesion was observed in the right temporal lobe, and it was heterogeneously enhanced with gadolinium. Suspecting a metastatic brain tumor, tumor resection with craniotomy was performed. Through pathological examination, the patient was diagnosed with brain metastasis of the breast cancer. Whole-brain irradiation was additionally performed. The patient recovered smoothly without neurological deficit and was discharged. No intracranial recurrence was noted on follow-up imaging, but the general condition aggravated, and the patient died after 13 months. Breast cancer in males may metastasize to the brain after a prolonged period in rare cases, for which follow-up examinations by imaging may be necessary.

Acute contrecoup epidural hematoma that developed without skull fracture in two adults: two case reports.

BACKGROUND: The incidence of acute epidural hematoma not accompanied by fracture is low, and it mostly occurs right below the impact point in children. Acute epidural hematoma on the contralateral side of the impact point without fracture is very rare. CASE PRESENTATION: Case 1: a 52-year-old Japanese woman fell and was bruised in the left occipital region, and acute epidural hematoma developed in the right frontal region. No fracture line was observed in the right frontal region on head computed tomography or during surgery, and the source of bleeding was the middle meningeal artery. Case 2: a 56-year-old Japanese man fell down the stairs and was bruised in the right occipital region, and acute epidural hematoma developed in the right occipital supra- and infratentorial regions and left frontal region. Separation of the lambdoid suture was noted in the right occipital region, but no fracture line was present in the left frontal region on either head computed tomography or during surgery, and the source of bleeding was the middle meningeal artery. CONCLUSIONS: Two rare cases of frontal contrecoup acute epidural hematoma without facture near the hematoma were reported. It is possible that the dura mater detaches from the inner surface of the skull due to cavitation theory-related negative pressure and blood vessels in the dura mater are damaged, causing contrecoup acute epidural hematoma even though no fracture occurs, for which careful course observation is necessary.

Clinical Characteristics of Subarachnoid Hemorrhage with an Intracerebral Hematoma and Prognostic Factors.

BACKGROUND: Subarachnoid hemorrhage (SAH) with an intracerebral hematoma (ICH) shows an unfavorable prognosis. In the present study, we examined the characteristics of SAH with ICH and its prognosis. METHODS: Subjects comprised 218 patients with SAH who underwent surgery between January 2007 and December 2015. We compared age, sex, the location of the aneurysm, treatment procedures, medical history (hypertension, diabetes, and heart disease), the Glasgow Coma Scale (GCS) score on admission, rerupture rate, hydrocephalus, the diameter of the aneurysm, cerebral vasospasm, perioperative cardiopulmonary complications, and the Glasgow Outcome Scale (GOS) score after 2 months between patients with SAH with and without ICH. The interval from the onset of SAH until surgery, the location of ICH, and hematoma volume were investigated as prognostic factors for SAH with ICH. RESULTS: Among all subjects, 82 had SAH with ICH. GCS scores on admission were poorer in patients with SAH with ICH than in those without ICH (P < .001), and middle cerebral artery aneurysms were more likely to form hematomas (P < .001). GOS scores after 2 months were also poorer in patients with SAH with ICH (P < .01). The size of aneurysms was larger in the 82 patients with SAH with ICH than in those without ICH (P < .001), and the rerupture rate was higher (P < .001). The unfavorable prognosis of patients with SAH with ICH was associated with age and GCS score on admission. CONCLUSIONS: A young age and a favorable GCS score on admission may be associated with a favorable prognosis for patients with SAH with ICH, and SAH with ICH may easily rerupture.

Operative simulation of anterior clinoidectomy using a rapid prototyping model molded by a three-dimensional printer.

BACKGROUND: As the anatomical three-dimensional (3D) positional relationship around the anterior clinoid process (ACP) is complex, experience of many surgeries is necessary to understand anterior clinoidectomy (AC). We prepared a 3D synthetic image from computed tomographic angiography (CTA) and magnetic resonance imaging (MRI) data and a rapid prototyping (RP) model from the imaging data using a 3D printer. The objective of this study was to evaluate anatomical reproduction of the 3D synthetic image and intraosseous region after AC in the RP model. In addition, the usefulness of the RP model for operative simulation was investigated. METHODS: The subjects were 51 patients who were examined by CTA and MRI before surgery. The size of the ACP, thickness and length of the optic nerve and artery, and intraosseous length after AC were measured in the 3D synthetic image and RP model, and reproducibility in the RP model was evaluated. In addition, 10 neurosurgeons performed AC in the completed RP models to investigate their usefulness for operative simulation. RESULTS: The RP model reproduced the region in the vicinity of the ACP in the 3D synthetic image, including the intraosseous region, at a high accuracy. In addition, drilling of the RP model was a useful operative simulation method of AC. CONCLUSIONS: The RP model of the vicinity of ACP, prepared using a 3D printer, showed favorable anatomical reproducibility, including reproduction of the intraosseous region. In addition, it was concluded that this RP model is useful as a surgical education tool for drilling.

Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenitis) with atypical encephalitis and painful testitis: a case report.

BACKGROUND: Kikuchi-Fujimoto disease is a self-limited clinicopathologic entity that is increasingly recognized worldwide. Kikuchi-Fujimoto disease is characterized by cervical lymphadenopathy occurring in young adults. Neurologic involvement is rare, and testitis directly caused by Kikuchi-Fujimoto disease has not yet been reported. CASE PRESENTATION: A 19-year-old man was brought to our clinic with complaints of fever, headache, fatigue, and left lower quadrant pain that had persisted for 3 weeks. On physical examination, painful cervical lymphadenopathies were observed. Meningitis was suspected based on a cerebrospinal fluid examination, and left-sided orchitis was diagnosed based on findings from magnetic resonance imaging and ultrasonography. However, neither antibiotics nor antiviral drugs were effective in treating the patient's symptoms. On the 20th day of hospitalization, the patient experienced a loss of consciousness, and brain T2-weighted magnetic resonance imaging showed asymmetrical, high-signal intensities in both basal nuclei and the left temporal lobe. Encephalitis was suspected, and the patient was treated with intravenous prednisolone pulse therapy (1 g/day) for 3 days and intravenous immunoglobulin therapy for 5 days. A left cervical lymph node biopsy showed apoptotic necrosis in paracortical and cortical areas with an abundance of macrophages and large lymphoid cells, which had irregular nuclei suggestive of Kikuchi-Fujimoto disease; the pathological findings from a brain biopsy were the same as those of the cervical lymph node biopsy. The encephalitis and cervical lymphadenopathies followed a benign course, as did the testitis. CONCLUSIONS: This is the first report of Kikuchi-Fujimoto disease involving painful testitis and pathologically proven asymmetrical brain regions. Kikuchi-Fujimoto disease should be included in the differential diagnosis when a patient presents with encephalitis, testitis, and fever of unknown origin.

Comparison between Quantitative Stiffness Measurements and Ultrasonographic Findings of Fresh Carotid Plaques.

Using a stiffness meter, we quantitatively measured the stiffness of fresh plaques that had been excised by carotid endarterectomy. The objective of this study was to clarify the correlation between plaque stiffness and pre-operative carotid ultrasonographic findings, and predict the stiffness of plaques before surgery by comparison with the stiffness of common items. The study population comprised 44 patients (44 lesions) who had undergone carotid endarterectomy at our institution between December 2009 and October 2014. The stiffness of excised fresh plaques was measured using a stiffness meter and compared with the pre-operative echographic findings for the plaques and the stiffness of selected foods and common items. The mean stiffness value for all plaques was 4.52 ± 3.30 MPa (mean ± standard deviation). The plaques exhibiting calcification were significantly harder (p = 0.001). On classification of lesions on the basis of echographic findings, plaque hardness was in the order low-echoic (15 lesions) < iso-echoic (20 lesions) < high-echoic (9 lesions) (p = 0.02). The stiffness of the low-echoic group was equivalent to that of tofu or sliced cheese, whereas the plaques in the iso- and high-echoic groups exhibited stiffness similar to that of ham and a plastic eraser, respectively. A significant correlation was observed between the quantitative stiffness values of carotid plaques and their brightness on carotid ultrasonography. Using these data, operators might be able to predict plaque stiffness from pre-operative echographic findings. In addition, it might be useful for operators to compare such quantitative stiffness measurements with stiffness data for foods and common items to gain an understanding of the state of the target plaque before treatment.

[A Rare Case of Metastatic Brain Tumors in the Bilateral Cerebellopontine Angles].

We encountered a rare case of metastatic brain tumors in the bilateral cerebellopontine angles. The patient was a 61-year-old man, who visited an otorhinolaryngology clinic with complaints of rapidly progressing bilateral hearing impairment and facial palsy. The patient was referred to our hospital because tumorous lesions were suspected in the bilateral cerebellopontine angles on brain magnetic resonance imaging. Regarding tumor markers, the patient's cancer antigen 19-9 and carcinoembryonic antigen levels were high, which suggested metastasis. However, no abnormal findings other than abdominal lymph node enlargement were detected on whole-body examination, and no primary lesion was identified. The tumor in the right cerebellopontine angle was excised using the lateral suboccipital approach and subjected to pathological examination. It was diagnosed as an adenocarcinoma; thus, both lesions were considered brain metastases from a malignant abdominal tumor, and radiochemotherapy was administered to the patient. Unfortunately, the patient died after 89 days of treatment, and a pathological autopsy revealed that the primary lesion was a common bile duct tumor. No dural metastasis was noted in the brain or spinal cord; however, tumors were detected in the epiarachnoid space during surgery. Metastasis to the bilateral cerebellopontine angles occurred in the same period, which was indicative of ascending metastasis through the vertebrobasilar artery. Hence, we suggest that progressive bilateral hearing impairment and facial palsy were a consequence of brain tumors that had metastasized bilaterally to the cerebellopontine angles.

A neurosurgical simulation of skull base tumors using a 3D printed rapid prototyping model containing mesh structures.

BACKGROUND: Deep regions are not visible in three-dimensional (3D) printed rapid prototyping (RP) models prepared from opaque materials, which is not the case with translucent images. The objectives of this study were to develop an RP model in which a skull base tumor was simulated using mesh, and to investigate its usefulness for surgical simulations by evaluating the visibility of its deep regions. METHODS: A 3D printer that employs binder jetting and is mainly used to prepare plaster models was used. RP models containing a solid tumor, no tumor, and a mesh tumor were prepared based on computed tomography, magnetic resonance imaging, and angiographic data for four cases of petroclival tumor. Twelve neurosurgeons graded the three types of RP model into the following four categories: 'clearly visible,' 'visible,' 'difficult to see,' and 'invisible,' based on the visibility of the internal carotid artery, basilar artery, and brain stem through a craniotomy performed via the combined transpetrosal approach. In addition, the 3D positional relationships between these structures and the tumor were assessed. RESULTS: The internal carotid artery, basilar artery, and brain stem and the positional relationships of these structures with the tumor were significantly more visible in the RP models with mesh tumors than in the RP models with solid or no tumors. CONCLUSIONS: The deep regions of PR models containing mesh skull base tumors were easy to visualize. This 3D printing-based method might be applicable to various surgical simulations.

Anatomical Reproducibility of a Head Model Molded by a Three-dimensional Printer.

We prepared rapid prototyping models of heads with unruptured cerebral aneurysm based on image data of computed tomography angiography (CTA) using a three-dimensional (3D) printer. The objective of this study was to evaluate the anatomical reproducibility and accuracy of these models by comparison with the CTA images on a monitor. The subjects were 22 patients with unruptured cerebral aneurysm who underwent preoperative CTA. Reproducibility of the microsurgical anatomy of skull bone and arteries, the length and thickness of the main arteries, and the size of cerebral aneurysm were compared between the CTA image and rapid prototyping model. The microsurgical anatomy and arteries were favorably reproduced, apart from a few minute regions, in the rapid prototyping models. No significant difference was noted in the measured lengths of the main arteries between the CTA image and rapid prototyping model, but errors were noted in their thickness (p < 0.001). A significant difference was also noted in the longitudinal diameter of the cerebral aneurysm (p < 0.01). Regarding the CTA image as the gold standard, reproducibility of the microsurgical anatomy of skull bone and main arteries was favorable in the rapid prototyping models prepared using a 3D printer. It was concluded that these models are useful tools for neurosurgical simulation. The thickness of the main arteries and size of cerebral aneurysm should be comprehensively judged including other neuroimaging in consideration of errors.

Hydroperoxide in internal jugular venous blood reflects occurrence of subarachnoid hemorrhage-induced delayed cerebral vasospasm.

BACKGROUND: To investigate the association between subarachnoid hemorrhage-induced delayed cerebral vasospasm (DCVS) and oxidative stress, an oxidation product, hydroperoxide, was measured in 3 specimens: peripheral arterial blood, cerebrospinal fluid (CSF), and internal jugular venous blood (IJVB). METHODS: Hydroperoxide was measured using the diacron reactive oxygen metabolites (d-ROMs) test. The hydroperoxide levels were evaluated based on the rate of change in the d-ROMs test value on day 6 relative with that on day 3 (d-ROMs change rate). RESULTS: The subjects were 20 patients. The d-ROMs change rate in IJVB was significantly higher in patients with DCVS on day 6 than in those without it (P < .01). When the patients were classified into the following 3 groups: Group A (no DCVS occurred throughout the clinical course); Group B (DCVS occurred, but no cerebral infarction [CI] was induced); and Group C (DCVS occurred and caused CI), the d-ROMs change rate in IJVB was the highest in Group C, followed by Group B then A (P < .01). The d-ROMs change rates in peripheral arterial blood and CSF were not related to the development of DCVS. CONCLUSIONS: It was concluded that the more severe DCVS occurs and is more likely to progress to CI as the IJVB hydroperoxide level rises early after the development of subarachnoid hemorrhage.