====== Epidural venous plexus ======

The [[epidural]] venous plexus is a network of interconnecting [[vein]]s located in the anterior epidural space, in the outermost part of the [[spinal canal]]. It runs from the [[skull base]] to the [[sacrum]]. It is surrounded by very little fat, although the levels increase towards the lower levels of the [[spine]].
----
Superficial [[siderosis]] of the [[central nervous system]] is a rare intractable [[disease]] induced by chronic [[subarachnoid hemorrhage]]. Neurological deficits, such as [[cerebellar ataxia]] and hearing difficulties, gradually progress if left undiagnosed. [[Hemosiderin]] deposition is irreversible because standard medical treatment has not yet been established. Interventions at the source of bleeding may be the key to a preferable outcome of treatment for chronic subarachnoid hemorrhage; however, the source is not clear in many cases.

Among the consecutive cases diagnosed with a spontaneous cerebrospinal fluid (CSF) leak, cases of superficial siderosis associated with a Cerebrospinal fluid fistula due to a ventral dural defect were retrospectively analyzed.

Among 77 cases of a Cerebrospinal fluid fistula, 7 cases (9%) of superficial siderosis were identified (median age of 59 years, male, 4 cases). Defects were diagnosed on 1-mm sliced fast imaging employing steady-state acquisition MRI (n = 5), conventional myelographic CT (n = 1), or dynamic myelographic CT (n = 1) at high thoracic levels (T1-T4). All defects were repaired by direct neurosurgery. During surgery, continuous bleeding from the [[epidural vein]]s of the vertebral [[epidural venous plexus]] was identified as the source of [[subarachnoid hemorrhage]]. Epidural CSF pulsations through the defect prevented [[clot]] formation by the epidural veins. Dural repair stopped free communication between the subarachnoid and [[epidural space]]s, leading to the disappearance of chronic subarachnoid hemorrhage.

Bleeding from the [[epidural venous plexus]] may be the cause of [[superficial siderosis]] associated with ventral [[dural defect]]s. Neurosurgical [[repair]] may stop the progression of this condition
((Takai K, Taniguchi M. Superficial siderosis of the central nervous system associated with ventral [[dural defect]]s: bleeding from the epidural venous plexus. J Neurol. 2021 Apr;268(4):1491-1494. doi: 10.1007/s00415-020-10319-2. Epub 2021 Jan 3. PMID: 33389031.)).