✓ A case of internal carotid artery dissection is presented. It was diagnosed by computerized tomography (CT) and confirmed by angiography. The typical clinical presentation and radiographic evaluation are briefly reviewed. High-resolution CT scanning with intravenous contrast enhancement is a valuable diagnostic aid in the diagnosis of this entity.
David J. Lubbers and Thomas A. Tomsick
Adam I. Lewis, Thomas A. Tomsick and John M. Tew Jr.
✓ The clinical, anatomical, and radiological features of nine cases of tentorial dural arteriovenous malformations (AVM's) are presented, and 45 reported cases are reviewed. Unlike dural AVM's of the transverse sigmoid and cavernous sinuses that usually have a benign natural history, dural AVM's of the tentorium typically present with hemorrhage or progressive neurological deficit. In this series, patients ranged in age from 52 to 72 years and included five men and four women. These patients presented with subarachnoid hemorrhage, parenchymal hemorrhage, brainstem dysfunction, cerebellar signs, and obstructive hydrocephalus. Malformations were fed principally by the meningohypophyseal trunk, branches of the middle meningeal artery, and the occipital artery. Venous drainage was uniform through the cortical veins (predominantly the mesencephalic, petrosal, and cerebellar veins). Eight of the nine patients had an associated venous aneurysm(s); two had more than one venous aneurysm, and two patients had a vein of Galen aneurysm associated with the tentorial dural AVM. Eight of nine patients improved after treatment, including four patients with complete obliteration of the dural AVM. Based on our experience, we have developed a treatment protocol for tentorial dural AVM's that uses transarterial embolization followed by direct microsurgery or stereotactic radiation. These therapies, applied in a staged manner, have proven safe and relatively effective for the treatment of dural AVM's.
Humberto J. Perata, Thomas A. Tomsick and John M. Tew Jr.
✓ The association between arteriovenous malformations (AVM's) and aneurysms is well documented in the literature. However, a specific type of aneurysm, termed a “pedicle” aneurysm, has received little attention despite its role as a primary source of hemorrhage. The authors report four recent cases of patients with cerebral AVM's who bled from aneurysms arising from the midportion of AVM-feeding artery pedicles. Angiography, computerized tomography, and magnetic resonance imaging confirmed the origin of the hemorrhage from the pedicle aneurysm in each case. Because pedicle aneurysms are at risk for recurrent rupture, they represent an important subclassification of aneurysms associated with AVM's. The authors have expanded the previous classification systems for aneurysms associated with AVM's to include pedicle aneurysms; this classification is based on the location of the aneurysm and its relationship to the malformation. Complete documentation of such aneurysms as the potential source of hemorrhage is recommended, and prompt intervention by embolization and/or surgical resection is indicated for this dangerous aneurysm associated with cerebral AVM's.
Hwa-Shain Yeh, Thomas A. Tomsick and John M. Tew Jr.
✓ Three cases of ruptured aneurysm of the distal posterior inferior cerebellar artery (PICA) presenting with isolated intraventricular hematoma are reported. All of the aneurysms originated from the lateral medullary segment of the PICA and ruptured into the lateral recess of the fourth ventricle. The diagnosis of distal PICA aneurysm should be considered if isolated intraventricular hematoma is found without obvious parenchymal hemorrhage or subarachnoid blood in the basal cisterns. Complete vertebral arteriography is a requisite for the recognition of this condition. The outcome in patients with these aneurysms should be good if surgical repair is performed before rebleeding occurs.
Eric W. Neils, Robert Lukin, Thomas A. Tomsick and John M. Tew
✓ The authors present two cases of herpes simplex encephalitis (HSE) in which computerized tomography (CT) scanning and magnetic resonance imaging (MRI) were performed. They also review the literature on the use of these imaging modalities in cases of HSE. The striking changes noted in these cases on T2-weighted magnetic resonance images in comparison to the CT findings suggest that MRI will help speed recognition of nonhemorrhagic HSE abnormalities.
Adam I. Lewis, Thomas A. Tomsick, John M. Tew Jr. and Michael A. Lawless
✓ Transarterial embolization of direct carotid—cavernous fistulas (CCFs) using detachable balloons is the best initial option for occlusion of the fistula and preservation of the internal carotid artery. However, the long-term safety and efficacy of this treatment is unknown. The authors reviewed the long-term outcome of 87 patients with 88 direct CCFs occluded by detachable balloons. Clinical follow up was obtained in 48 (83%) of 58 patients treated with latex balloons (mean follow-up period 10 years, range 5.9–15.5 years) and 28 (97%) of 29 patients treated with silicone balloons (mean follow-up period 4 years, range 1–6.6 years). Two patients were treated with both balloon types. There were no late recurrent symptoms of cranial bruit, proptosis, chemosis, or arterialized conjunctiva in patients treated with either latex or silicone balloons. Diplopia improved in all patients; however, five patients required shortening of the lateral rectus muscle. Delayed ischemia occurred in three patients: one patient had a transient ischemic episode 5 years after treatment with latex balloons and two patients (85 and 90 years old) who had ruptured spontaneous intracavernous aneurysms suffered cerebral infarctions 6 weeks and 4 months, respectively, after treatment with silicone balloons. There were five deaths in the series unrelated to balloon treatment. These results show that after transarterial embolization of direct CCFs using either silicone or latex detachable balloons, the long-term risks are low for fistula recurrence, symptomatic foreign body reaction, symptomatic pseudoaneurysm formation, and cerebral ischemia.
Frank Eggers, Robert Lukin, A. Alan Chambers, Thomas A. Tomsick and Raymond Sawaya
✓ A case of iatrogenic carotid-cavernous fistula secondary to a Fogarty catheter thrombectomy is presented. The literature and seven previously reported cases are reviewed.
Norberto Andaluz, Thomas A. Tomsick, Jeffrey T. Keller and Mario Zuccarello
✓Given the relatively benign natural history of cavernous carotid artery aneurysms and based on anecdotal reports in the literature of subarachnoid hemorrhage (SAH) or subdural hemorrhage (SDH) from these aneurysms, observation is warranted and typically recommended. In this case report, the authors describe a woman who harbored a partially thrombosed, giant cavernous aneurysm that ruptured after she underwent a balloon occlusion test (BOT) and predominately led to an SDH. The authors believe that this occurrence is the first such report in the English literature. They discuss possible mechanisms for this event and the literature related to SAH or SDH from cavernous aneurysms, including why cavernous aneurysms cause such hemorrhages. The authors also recommend that attention be paid to such lesions regarding the possibility of aneurysmal rupture following a BOT.
Glenn L. Keiper Jr., Jonathan D. Sherman, Thomas A. Tomsick and John M. Tew Jr.
Object. The goal of this study was to document the hazards associated with pseudotumor cerebri resulting from transverse sinus thrombosis after tumor resection. Dural sinus thrombosis is a rare and potentially serious complication of suboccipital craniotomy and translabyrinthine craniectomy. Pseudotumor cerebri may occur when venous hypertension develops secondary to outflow obstruction. Previous research indicates that occlusion of a single transverse sinus is well tolerated when the contralateral sinus remains patent.
Methods. The authors report the results in five of a total of 107 patients who underwent suboccipital craniotomy or translabyrinthine craniectomy for resection of a tumor. Postoperatively, these patients developed headache, visual obscuration, and florid papilledema as a result of increased intracranial pressure (ICP). In each patient, the transverse sinus on the treated side was thrombosed; patency of the contralateral sinus was confirmed on magnetic resonance (MR) imaging. Four patients required lumboperitoneal or ventriculoperitoneal shunts and one required medical treatment for increased ICP. All five patients regained their baseline neurological function after treatment. Techniques used to avoid thrombosis during surgery are discussed.
Conclusions. First, the status of the transverse and sigmoid sinuses should be documented using MR venography before patients undergo posterior fossa surgery. Second, thrombosis of a transverse or sigmoid sinus may not be tolerated even if the sinus is nondominant; vision-threatening pseudotumor cerebri may result. Third, MR venography is a reliable, noninvasive means of evaluating the venous sinuses. Fourth, if the diagnosis is made shortly after thrombosis, then direct endovascular thrombolysis with urokinase may be a therapeutic option. If the presentation is delayed, then ophthalmological complications of pseudotumor cerebri can be avoided by administration of a combination of acetazolamide, dexamethasone, lumbar puncture, and possibly lumboperitoneal shunt placement.