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Background: Midbrain cavernoma associated with Holmes' tremor is a rare entity. Although there have been 4 other cases of Holmes' tremor caused by a cavernoma, this is the first case that was cured by surgical removal of the cavernoma. In addition, heavy ossification and Holmes tremor as a clinical presentation are 2 unusual features of the cavernoma. Possible mechanisms of these very rare entities are discussed in relation to the present report and relevant literature is reviewed., Case Description: We present a case of 60-year-old woman with heavily ossified cavernoma of the thalamomesencephalic junction with neuroimaging and histologic features. The only manifestation was Holmes' tremor. The patient was operated on via posterior interhemispheric approach while in the sitting position. After the arachnoid folds of the quadrigeminal cistern were opened, the thin neural tissue on the surface of the dorsal midbrain was incised and the lesion was visualized and totally removed as a single piece. The tremor was almost completely suppressed., Conclusion: Ossified cavernoma is a rare entity but has a characteristic MRI appearance. It should be considered in the differential diagnosis of intracerebral hypointense lesions on both T1- and T2-weighted MR images because they are potentially curable by surgical removal.

Background: Distal AChoA aneurysms are quite rare. Only 12 operated cases have been reported in the English medical literature. Treatment of these aneurysms is also difficult because of their deep location, small size, and angioarchitecture., Methods: The authors report 2 additional patients with aneurysms, arising from the distal AChoA and located within the temporal horn of the lateral ventricle. In the first patient, the aneurysm could also be visualized with CTA, which is the first demonstration in the literature., Results: The aneurysms were explored and resected via a transtemporal/ventricular approach in both patients. One patient was discharged as neurologically intact and the other died because of severe vasospasm., Conclusions: The conclusions drawn from our experience and a comprehensive review of the literature include the following: (1) A distal AChoA aneurysm should be considered in patients with isolated medial temporal intracerebral hematoma with intraventricular extension. (2) These aneurysms are frequently very small (<5 mm). Therefore, they cannot be detected on initial angiograms in some cases. (3) These small aneurysms cannot be usually clipped without sacrificing the parent artery. (4) Sacrificing distal AChoA (beyond the plexal point) does not usually cause any neurological deficit, but, whenever possible, this artery should be preserved.

Background: Some neurosurgical procedures have high morbidity and mortality rates due to cerebrospinal fluid (CSF) fistula development, particularly when dural defects are in relatively inaccessible areas or surrounded by friable dura. We used a rat model to test 4 different dural closure techniques to determine which one was significantly superior for achieving a watertight dural closure with minimal harm to brain tissue., Methods: The rats were randomly divided into 2 groups. The first group (group A, n = 40) was used to test the strength of the adhesivity for CSF leakage. Histopathologic studies were used to evaluate the granulation tissue between the dura and dural graft. Effects on the brain tissue were studied in the second group (group B, n = 40) where lipid peroxidation was determined. These 2 groups consisted of 5 subgroups: control, methyl metacrylate, n-butyl cyanoacrylate, fibrin glue, and CO(2) laser., Results: Methyl metacrylate and CO(2) laser techniques were inadequate for stopping dural leakage and had harmful effects on brain tissue. Cerebrospinal fluid leak was observed only in 1 rat in the n-butyl cyanoacrylate subgroup and this result was statistically significant (P = .0005), but lipid peroxidation levels for this material showed that it was not safe for dural closure in case it leaked through the dural defect. The lipid peroxidation levels of the fibrin glue subgroup were not statistically significantly different from the control group (P = .440)., Conclusions: Fibrin glue was the safest material with a CSF leakage risk that was higher than n-butyl cyanoacrylate (25% vs 12.5%) but acceptable. This study showed no relationship between the CSF leak and histopathologic findings for sealant properties of the tissue adhesives.

Background: Granular cell tumors in the central nervous system are quite rare. To date, only 6 cases of granular cell tumor arising from cranial nerves have been reported in the literature. To the best of our knowledge, we present the first case of a predominant intracavernous granular-cell tumor arising from oculomotor nerve., Case Presentation: A 42-year-old man presented with third-nerve paresis and decreased visual acuity on the left side. Magnetic resonance imaging showed a mainly intracavernous mass partially extending to the superior orbital fissure and entrance of the optic canal. Using a pterional craniotomy, the tumor was removed from within the cavernous sinus via combined superior and lateral intradural approach, and optic nerve was also decompressed. Histologically, the tumor was diagnosed as a granular cell tumor., Conclusions: Although it is quite rare, granular cell tumor should be included into the differential diagnosis of intracavernous masses because surgical treatment is curative.

Objective: Although spinal intradural arteriovenous malformations have frequently been associated with venous aneurysms, spinal dural arteriovenous fistulas typically are not. We describe a case of conus medullaris compression by a large saccular venous aneurysm of a spinal dural arteriovenous fistula. As these lesions are slow-flow arteriovenous shunts, development of a venous aneurysm is an unexpected condition. Pathogenesis of these aneurysms is briefly discussed., Methods: A 61-year-old man presented with progressive spastic paraparesis of 1-year duration. Spinal magnetic resonance (MR) suggested abnormal serpiginous vessels and a partially thrombosed aneurysm at the level of conus medullaris. Spinal angiography was performed but some lower thoracal and upper lumbar segments could not be catheterized because of severe atherosclerosis. As a result, vascular anomaly could not be demonstrated angiographically, but surgical exploration was found to be necessary because of positive clinical and MR findings., Results: An arteriovenous fistula that entered the spinal canal beneath the L1 pedicle on the left was identified. It was easily coagulated and cut. The partially thrombosed aneurysm within the conus medullaris was also resected., Conclusions: Our case illustrates two important points related to patients harboring spinal dural arteriovenous fistulas (AVF): First, clinical suspicion and MR findings are important in diagnosis of these lesions and surgical exploration is indicated despite negative or nondiagnostic angiographic results in such cases. Second, venous aneurysms may be associated with spinal dural AVFs, and although spinal dural AVFs are low-flow lesions, the development of the venous aneurysm is probably a result of high venous pressure.

Background: Spinal dural and intradural arteriovenous fistulas (AVFs) have been the subject of numerous reports but purely epidural AVFs causing venous congestion within the spinal cord are rare., Case Description: We describe a patient with an exclusively epidural arteriovenous fistula and congestive myelopathy. There are three interesting features of this case as described below: 1) The presence of a purely epidural AVF of the cranio-cervical junction. According to our knowledge this is the first case of an AVF in this location. 2) The lesion was angiographically occult. This was probably because of the extremely slow flow of the fistula. 3) Despite the negative angiograms, exploratory surgery was conducted because of positive clinical and MR findings., Conclusions: Epidural AVF/AVM of the foramen magnum should be considered in the differential diagnosis in patients with chronic myelopathy, even if cranial and spinal angiograms are negative. In these cases, we recommend that if clinical and radiological investigations strongly suggest the presence of an arteriovenous fistula, surgical exploration should be performed.

Background: Intracranial aneurysms and systemic arterial hypertension coexist in a high percentage of patients. The relationship between intracranial aneurysms and hypertension is poorly defined., Methods: Therefore, we reviewed the role of hypertension in the pathogenesis of saccular aneurysms as previously reported in clinical, experimental, and autopsy studies., Results: Among 24 relevant clinical and/or autopsy studies, the mean incidence of pre-existing hypertension was 43.5% in aneurysm patients compared to 24.4% in the normal population. Although definitive evidence is lacking, data from multiple types of investigations indicate that systemic arterial hypertension creates a greater risk for the development of intracranial aneurysms than previously believed. The underlying pathophysiological mechanism(s) are also poorly defined., Conclusions: We propose a unifying hypothesis: Endothelial injury, occlusion of the vasa vasorum, and disruption of the synthesis of collagen and elastin are likely the most important factors in initiating the development of aneurysms. Chronic hypertension potentially affects all of these factors. Consequently, chronic hypertension may cause intimal thickening, necrosis of the tunica media, changes in the compositional matrix, and degeneration of the internal elastic lamina to develop in the arterial wall. These structural changes could cause a focal weakening in the arterial wall with resultant bulging. This theory accounts for the high incidence of intracranial aneurysms in the absence of any known associated hereditary or connective-tissue disease. Nor does it exclude the possibility of other etiological factors. From the perspective of prevention, however, it offers clear opportunities for prophylaxis.

Background: An extremely rare case of intracranial aneurysm associated with catecholamine-secreting carotid body tumor is presented., Case Description: A 64-year-old woman suffering from hypertensive attacks was admitted first to the Otolaryngology Department with a neck swelling. Right common carotid angiography revealed a hypervascular mass at the carotid bifurcation. On the same angiogram a middle cerebral artery aneurysm was discovered incidentally and the patient was referred to the Neurosurgical Department. Because of her history the tumor was considered to be endocrinologically active and the patient underwent alpha- and beta-blockade to protect intraoperative cardiovascular instability. Despite all precautions, during the operation hypertensive crises developed and the aneurysm was clipped with difficulty., Conclusion: Perioperative management designed to avoid complications in treating this rare association is discussed. Although this is the first reported case of an intracranial aneurysm associated with a functional carotid body tumor, a possible etiopathogenesis of the relationship between the aneurysm and hypertensive attacks due to an acute catecholamine-discharging tumor is presented.

Objective: A case of postoperative tension pneumocephalus after low basilar trunk aneurysm clipping is presented. To our knowledge, this is the first case of isolated prepontine tension pneumocephalus., Background: A 63-year-old woman was admitted for repair of a basilar aneurysm that had caused a subarachnoid hemorrhage. She was cooperative and partially oriented. According to Hunt & Hess classification, she was considered Grade III., Method: The aneurysm was clipped, using a right lateral suboccipital craniectomy with the patient in the sitting position. In the early postoperative period, she had no new neurological deficit. However, 2 hours later the patient became lethargic and unresponsive to verbal commands. Emergency CT scan revealed an isolated prepontine tension pneumocephalus with prominent posterior displacement of the pons. She was immediately taken back to surgery. Upon incision of the dura mater, air could be heard escaping under pressure from the posterior fossa cavity. The clip was in its proper position and all arteries were patent. Spontaneous respiration and pupil reflexes returned soon after surgery, but she remained unconscious and died 3 days later., Conclusion: We believe that this death was directly attributable to the tension pneumocephalus and the distortion of the pons. Postoperative prepontine tension pneumocephalus, although this is an extremely rare condition, should be considered if a patient deteriorates after basilar aneurysm surgery in the sitting position.

Background: Distal anterior cerebral artery aneurysms are rare and compose about 4.5% of all intracranial aneurysms. They generally arise at the bifurcation of the pericallosal and callosomarginal arteries. Their surgical approach is different from those of other anterior circulation aneurysms. These aneurysms present some special difficulties for neurosurgeons, including narrow exposure in the interhemispheric fissure, dense adhesions between the cingulate gyri, difficulty in controlling the parent artery, and the association of multiple aneurysms and vascular anomalies., Methods: Between January 1975 and May 1996, 14 cases of saccular aneurysms of the distal anterior cerebral artery were operated at the University of Hacettepe. The clinical presentations, neuroradiological findings, and operative approaches of these aneurysms were analyzed. In addition, the clinical series and isolated case reports in the English literature were also extensively reviewed., Results: The incidence of the aneurysms in this location was 2.8% of a total of 494 surgically treated cases in our center. Of 14 patients, eight were women and six were men. Multiple aneurysms were found in five patients (35%). All patients were operated via the interhemispheric route. Thirteen patients had good outcome and one patient died., Conclusions: We believe that all difficulties related to distal anterior cerebral artery aneurysms can be minimized with sufficient knowledge of microsurgery and surgical anatomy, using microtechniques and experience.

Endovascular therapy for cerebral arteriovenous malformations, although generally accepted to be a safe procedure, is not without risks. We present a patient with a 20 cm free segment of a catheter in the anterior circulation as a complication of embolization. This is a very rare complication. To our knowledge, only six cases have been reported in the literature. We believe this to be the first reported case of this complication treated surgically via craniotomy and arteriotomy.

Background: Pulmonary embolism continues to be a frequent cause of morbidity and mortality in neurosurgical practice. This study was designed to investigate the presence of signs and/or symptoms helpful for an early diagnosis of pulmonary embolism and to evaluate the safety of heparin treatment in neurosurgical patients., Method: We retrospectively reviewed 37 patients with pulmonary embolism among 6081 operated patients within the past 8 years at the Department of Neurosurgery, University of Hacettepe., Results: The overall incidence of pulmonary embolism was 0.42% and the mortality rate was 59.4%. The patients with cerebrovascular lesions had a significantly higher risk of pulmonary embolism compared with other neurosurgical pathologies. All patients were treated with heparin and subsequent oral warfarin therapy. None had intracranial or intraspinal bleeding while receiving anticoagulant therapy., Conclusions: This study demonstrates that pulmonary embolism has a high mortality rate and heparin therapy can be used safely and without fear of intracranial or intraspinal bleeding.

Aneurysmal bone cyst rarely affects the skull. We report two cases of aneurysmal bone cyst of the frontal bone. One of the cases is associated with pregnancy. The association of pregnancy with aneurysmal bone cyst and enlargement of the aneurysmal bone cyst during the pregnancy have been discussed.