The rate of head injury is 1.86-6 times higher for snowboarding than for skiing. Detailed data about the usefulness of a helmet or knit cap for protecting against serious head injuries have not been reported. The present study evaluated the use of a helmet or knit cap for preventing head injuries. Questionnaire data were collected from 1,190 consecutive patients in a hospital during the 1999/2000-2002/2003 winter seasons at Uonuma ski resort, Niigata, Japan. Patients were divided into the helmet, knit cap, and no cap groups. Upper technical level was highest and jumping as the cause of injury was most frequent in the helmet group. After adjustment for other confounders, there was a significant negative association between the occurrence of serious head injury during snowboarding and female sex (adjusted odds ratio 0.55, 95% confidence interval 0.421-0.718, p < 0.0001) and a significant positive association between serious head injury and jumping (adjusted odds ratio 2.25, 95% confidence interval 1.48-3.43, p = 0.0001). Among snowboarding maneuvers, only jumping showed a significant negative association between wearing of a helmet or knit cap and the occurrence of serious head injury (p = 0.036). Snowboarders who wear helmets might attempt dangerous maneuvers causing injuries. Wearing of a helmet or knit cap protected against serious head injuries on jumping. Every snowboarder should wear a helmet or knit cap on jumping to prevent head injury.

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Cardiac complication is a leading cause of death in the perioperative period after non-cardiac surgery. The present study retrospectively investigated perioperative cardiac complications after spinal fusion surgery in 901 consecutive adult patients who underwent fusion surgery in the lumbar spine from January 2005 to December 2006. Cardiac complications developed in seven patients (0.8%), four males and three females aged 62 to 75 years (mean 66.6 years), in the perioperative period (myocardial infarction in 6 and angina pectoris in 1). Cardiac complications developed after mini-open transforaminal lumbar interbody fusion in four patients and after anterior lumbar interbody fusion in three. No patient had any symptoms related to cardiac disease before surgery. Common features were age over 60 years, a medical history of hypertension and/or diabetes mellitus, and presence of calcified atherosclerosis of the abdominal aorta and/or common iliac arteries. Five patients improved after conservative medical treatment in an intensive care unit. Percutaneous transluminal coronary angioplasty was performed in one patient and coronary artery bypass graft surgery in one. The possibility of perioperative cardiac complications should be considered before lumbar fusion surgery, especially in elderly patients with hypertension and/or diabetes mellitus, and calcified atherosclerosis of the abdominal aorta and/or common iliac arteries.

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A 52-year-old man presented with an anterior communicating artery aneurysm associated with splitting, penetration, and visual symptoms of the optic nerve and manifesting as sudden onset of severe headache. Angiography disclosed a 10-mm anterior communicating artery aneurysm projecting supero-posteriorly, and operative findings revealed unexpected splitting of the optic nerve. Moreover, the optic nerve was not in direct contact with the aneurysm fundus. Splitting of the optic nerve without the presence of a penetrating aneurysm is extremely rare. The pathogenesis of optic nerve penetration may involve congenital fenestration of the optic nerve.

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A 38-year-old man presented with a dissecting aneurysm of the left proximal posterior inferior cerebellar artery (PICA) manifesting as Wallenberg’s syndrome. The patient was treated by endovascular occlusion of the aneurysm and parent artery. Immediately after the treatment, the PICA territory was supplied by collateral circulation via the ipsilateral anterior inferior cerebellar artery. Seven days later, endogenous revascularization of the distal PICA territory had occurred via collateral circulation from the posterior meningeal artery (PMA). This unusual collateral circulation was thought to occur through a pre-existing anastomotic channel between the primitive vessels of the PICA and the PMA during subclinical hypoperfusion of the distal PICA territory. This unusual case demonstrates the potential for delayed development of collateral circulation from the PMA to the PICA territory.

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A 32-year-old man presented with a primary intraosseous cavernous hemangioma manifesting as a small painless swelling of the right forehead. Radiography revealed a radiolucent osteolytic lesion in the right frontal region. Bone window computed tomography demonstrated a 1.5 cm mass between the outer and inner tables just lateral to the right frontal sinus. The outer and inner tables were thin and partially defective, but without bone fracture. Magnetic resonance imaging revealed a small mass lesion with bone erosion of the posterior table of the frontal bone. Preoperative examination yielded no final diagnosis. En bloc resection was performed. The histological diagnosis was primary intraosseous cavernous hemangioma. Total resection is recommended for definitive diagnosis of intraosseous tumor.

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A 65-year-old man presented with a rare case of cavernous malformation with hemorrhage located within vestibular schwannoma. He had suffered hearing impairment for 20 years, and was admitted to our hospital with vertigo and ataxic gait. Neurological examination revealed hearing loss, facial nerve paresis, and left cerebellar ataxia. Magnetic resonance imaging demonstrated a left vestibular schwannoma 35 mm in diameter, as well as a heterogeneous area associated with hypointense rim within the tumor, indicating intratumoral hemorrhage. Subtotal removal of the tumor together with the fibrously encapsulated hematoma was performed through a left retrosigmoid craniotomy. Histological examination of the surgical specimen revealed cavernous malformation within vestibular schwannoma. Immunohistochemistry for matrix metalloproteinase (MMP)-2 and -9, and tissue inhibitors of metalloproteinase-2 showed strong expression in the endothelial cells of the cavernous malformation, but not in the interstitial structures. His symptoms significantly improved after surgery and he underwent gamma-knife therapy for the residual tumor. Cavernous malformations may show dynamic characteristics such as repeated hemorrhage and de novo formation. MMP-2 and -9, which are implicated in angiogenesis and hemorrhage, may be upregulated in such tumors.

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A 51-year-old woman presented with a rare completely intradural and extramedullary spinal ganglioneuroma associated with multiple hamartoma syndrome and manifesting as complaints of neck pain and dizziness persisting for 8 months. Magnetic resonance imaging of the spinal cord revealed an intradural extramedullary lesion at the C1 level. She underwent right suboccipital craniectomy and C1-2 hemilaminectomy to remove the tumor. Histological examination confirmed ganglioneuroma. She also suffered from multiple facial trichilemmomas, thyroid goiter, multiple polyposis of the gastrointestinal tract, and pulmonary hamartoma indicating multiple hamartoma syndrome. These benign neoplasms were treated conservatively.

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A 68-year-old woman presented with an extremely rare brain abscess associated with old and acute hemorrhages manifesting as gradual onset of symptoms of headache and fever. Magnetic resonance imaging clearly visualized the hemorrhage as heterogeneously hyperintense on diffusion-weighted imaging, concentric hypo-isointense on T₁-weighted imaging, and homogeneously hyperintense with a hypointense rim on T₂^*-weighted imaging. T₁-weighted imaging with contrast medium revealed a well-enhanced cyst wall. In spite of treatment with antibiotics, the neurological status of the patient deteriorated due to expansion of the abscess and perifocal edema. Needle aspiration of the cyst yielded bloody purulent fluid. The magnetic resonance imaging findings indicate that neovascularization of the cyst wall is involved in the mechanism of hemorrhage in brain abscess. Careful follow-up examinations are recommended in patients with brain abscess to detect warning signs of neurological deterioration.

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A 24-year-old man presented with closed-lip schizencephaly around the right central sulcus manifesting as an 11-year history of intractable epilepsy. Mild motor paresis in the left extremities and mental retardation were observed. Tonic posture with bilateral facial tonic contraction was asymmetrical, predominantly in the left extremities. Magnetic resonance imaging demonstrated closed-lip schizencephaly around the right central sulcus. The epileptogenic zone was determined in the supplementary motor area, and premotor and primary sensorimotor cortices using invasive recordings. As the thickened cortex was considered functional, corticectomy of the supplementary motor area and premotor area was performed, preserving the primary sensorimotor area. Histological examination revealed marked cortico-subcortical gliosis, particularly in the medial part of the resection. Asymmetrical tonic postural seizure disappeared completely after surgery. Medically intractable epilepsy with schizencephaly represents a considerable challenge in epilepsy surgery. Partial corticectomy adjacent to the thickened cortex was effective for seizure control in a patient with closed-lip schizencephaly around the central sulcus.

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A simple new method for making a rat post-angioplasty stenosis model was developed using a single-lumen compliant balloon catheter/guidewire system and no special diet. This technique was applied to 10 9-week-old Wistar rats fed a normal diet. The catheter/guidewire system was inserted from the external carotid artery and advanced retrogradely into the common carotid artery. The balloon was inflated six times with rotation through 60°. After angioplasty, the external carotid artery was ligated. Homogeneous stenoses due to intimal hyperplasia were demonstrated in cross sections of all cases. This simple and gentle method allows an easily reproducible post-angioplasty stenosis model.

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