Updating Superficial Siderosis of the Central Nervous System: Bleeding of a Dorsal Osteophyte into the Subarachnoid Space from a Perforating Artery

Superficial siderosis of the central nervous system (SSCNS) is an uncommon and often unrecognized disorder that results from recurrent and persistent bleeding into the subarachnoid space. Currently, there is no effective treatment for SSCNS. The identification and surgical resolution of the cause of bleeding remains the most reliable method of treatment, but the cause of bleeding is often not apparent. The identified sources of recurrent bleeding have typically included neoplasms, vascular malformations, brachial plexus or nerve root injury or avulsion, and previous head and spinal surgery. An association between recurrent bleeding in the CNS and dural abnormalities in the spine has recently been suggested. Dural tears have been identified in relation to a protruding disc or osteophyte. Also in these patients, the exact mechanism of bleeding remains unknown because of a lack of objective surgical data, even in patients who undergo neurosurgical procedures.The present case concerns a 48-year-old man who presented with longstanding symptoms of mild hearing loss and mild gait ataxia. A diagnosis of SSCNS was made in light of the patient's history and the findings on physical examination, imaging, and laboratory testing. MRI and CT detected a small calcific osteophyte in the anterior epidural space of T8-9. The patient underwent surgical removal of the bone spur and dural tear repair. During the surgery, the authors detected a perforating artery, which was on the osteophyte, that was bleeding into the subarachnoid space. This case shows a possible mechanism of chronic bleeding from an osteophyte into the subarachnoid space. In the literature currently available, a perforating artery on an osteophyte bleeding into the subarachnoid space has never been described in SSCNS.