Publications by authors named "Tsunemaro Koyama"

Lumbar interbody fusion is a widely accepted surgical procedure for patients with lumbar degenerative spondylolisthesis and lumbar spinal instability in the active age group. However, in elderly patients, it is often questionable whether it is truly necessary to construct rigid fixation for a short period of time. In recent years, we have been occasionally performing posterior dynamic stabilization in elderly patients with such lumbar disorders.

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A 29-year-old man presented with an intramedullary schwannoma of the conus medullaris manifesting as an 8-month history of mild bladder dysfunction, sexual impotence, and paresthesia in the buttocks. Subtotal removal of the lesion was achieved, as part of the tumor showed dense adhesion to the rostral neural tissue, with only postoperative transient deterioration of bladder dysfunction. Intramedullary schwannoma, especially involving the conus medullaris and the proximal spinal cord, is relatively rare and the pathogenesis and pathophysiology are unclear.

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A woman in her early twenties presented with cerebellar tonsillar herniation with syrinx in the cervicothoracic spinal cord manifesting as postural headache after suffering trauma to the hip. She was treated under a diagnosis of traumatic intracranial hypotension. Cranial magnetic resonance (MR) imaging demonstrated tonsillar herniation to the upper rim of the C1 lamina, associated with effacement of the basal cisterns and flattening of the pons against the clivus, sagging of the optic chiasm, and protrusion of the pituitary gland into the suprasellar cistern.

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Objective: Spinal nerve sheath tumors arise from the spinal nerve root and grow along it. There are two sites at which the growth of a tumor is restricted: the dural aperture for the spinal nerve root and the intervertebral foramen. This article describes the growth pattern of a spinal nerve sheath tumor along the spinal nerve root at various spinal levels.

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Background: Intracranial varices are rare and most are associated with vein of Galen arteriovenous malformations (AVM) or fistulas (AVF).

Description: A 43-year-old left-handed man presented with right hemihypesthesia and spastic gait. Neuroradiological examination revealed a spinal AVF and a giant intracerebral varix associated with a high-flow pial AVF.

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The authors report 2 cases of primary spinal intramedullary lymphoma and review all previously reported magnetic resonance imaging findings on this disease. The most common finding was a solid and homogeneously enhanced mass that was hyperintense on T2-weighted images, without associated syringomyelia. In a few cases, swelling of the spinal cord was minimal.

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