It is difficult to assess the natural history of intracranial vascular malformations because they are varied in nature, they are frequently silent clinically, they are often treated when they are discovered, and untreated lesions are not often followed in an organized way. Capillary telangiectasias are usually occult lesions of no clinical significance. Cavernous hemangiomas may cause seizures and may bleed, but the approximate yearly risks of bleeding and of death have not been determined. Venous angiomas seldom cause symptoms, with the exception that those in the cerebellum seem to have a propensity to bleed. Intracranial dural arteriovenous malformations (AVMs) may bleed and may cause brain injury if there is insufficient outflow into a dural venous sinus. The dural AVMs that drain into the cavernous sinus have a more benign course than those that drain into the transverse or sigmoid sinus. The aneurysm of the vein of Galen presents a different clinical picture and threat to health according to whether the patient is a neonate, an infant, or an older child. The AVM of the brain encountered in the adult usually presents with hemorrhage or seizures. An unruptured AVM has approximately a 2 to 3% risk of bleeding per year, with about a 1% risk of death per year. The mortality rate of the first hemorrhage is about 10%. Among the survivors, there is about a 6% chance of rebleeding during the 1st year and then approximately a 2 to 3% risk of bleeding per year subsequently. The mortality rate associated with a second hemorrhage is about 13%, and for subsequent hemorrhages the mortality is roughly 20%.
Recurrent vascular compression was seldom identified during posterior fossa reexploration for failed MVD in patients with persistent or recurrent TN or HFS. The previously placed Ivalon sponge or Teflon implant was consistently found to be in good position. Partial sensory trigeminal rhizotomy is an often effective alternative in cases of recurrent TN when neurovascular compression is not identified. However, because of the relatively high incidence of complications associated with reexploration, we recommend other ablative or medical treatments for most patients after failed MVD for TN or HFS.
Spontaneous cerebrospinal otorrhea (SCSFO) from tegmen or posterior fossa defects is uncommon. Twenty-nine cases have been detailed in the literature to date. We report an additional four cases from three patients. This group of 33 cases of SCSFO from tegmen or posterior fossa defects is characterized by certain clinical features. These patients are usually older adults (mean age 48 years, range 8 months to 80 years). Aural fullness with a serous appearing middle ear effusion, or clear otorrhea, often subsequent to tube myringotomy, are the usual initial symptoms. Meningitis was the initial manifestation in eight patients (24%), and ultimately occurred in an additional four patients (12%). The pathophysiologic basis for SCSFO from tegmen defects is discussed. Methods for diagnosing and treating CSF otorrhea from tegmen defects are reviewed.
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