Superficial siderosis: bleeding from the bone marrow after laminectomy for spinal tumor removal.

Superficial siderosis of the CNS is a rare disease characterized by the deposition of hemosiderin in the subpial layers of the CNS as the result of chronic subarachnoid bleeding. The arrest of bleeding is important for preventing the progression of this disease; however, the exact source of bleeding remains unknown in most cases because of a lack of objective surgical data. The authors of this report have described a unique case of superficial siderosis following cervical laminectomy and autograft fusion for the removal of a spinal schwannoma; the bleeding source was verified by intraoperative and histopathological findings. The patient exhibited no obvious neurological deficits, such as hearing loss or cerebellar ataxia, when the superficial siderosis was diagnosed, although there were the social impairments associated with schizophrenia. During repair surgery, the bleeding source was revealed as the bone marrow vasculature of the remaining vertebral arch, and not the fragile vessels at the dural defect or the residual tumor. Chronic bleeding was stopped before the onset of irreversible neurological deficits in this case. Bone marrow exposed to the intrathecal space may represent a chronic bleeding source in patients with superficial siderosis following CNS surgery including laminectomy or craniotomy. The following recommendations have been proposed for superficial siderosis of the CNS from both a preventative and a therapeutic perspective: 1) During CNS surgery, neurosurgeons should make every effort to prevent exposing bone marrow to the intrathecal space to avoid the risk of chronic subarachnoid bleeding. 2) In the case of a large dural defect and pseudomeningocele following CNS surgery, bone marrow around the dural defect should be considered as the bleeding source of superficial siderosis, and such cases should undergo revision surgery before the progression of this disease.