The efficacy of silver-embedded polypropylene-grafted polyethylene glycol-coated ventricular catheters on prevention of shunt catheter infection in rats.

PURPOSE: Catheter-related infection is a major complication of ventriculoperitoneal shunt in children. The aim of this study is to determine inflammatory response and the efficacy of polypropylene-grafted polyethylene glycol (PP-g-PEG) copolymer and silver nanoparticle-embedded PP-g-PEG (Ag-PP-g-PEG) polymer-coated ventricular catheters on the prevention of catheter-related infections on a new experimental model of ventriculoperitoneal shunt in rats. METHODS: Thirty six Wistar albino rats were divided into six groups: group 1, unprocessed sterile silicone catheter-embedded group; group 2, sterile PP-g-PEG-coated catheter group; group 3, sterile Ag-PP-g-PEG-coated catheter group; group 4, infected unprocessed catheter group; group 5, infected PP-g-PEG-coated catheter group; and group 6, infected Ag-PP-g-PEG-coated catheter group, respectively. In all groups, 1-cm piece of designated catheters were placed into the cisterna magna. In groups 4, 5, and 6, all rats were infected with 0.2 mL of 10 × 10(6) colony forming units (CFU)/mL Staphylococcus epidermidis colonies before the catheters were placed. Thirty days after implantation, bacterial colonization in cerebrospinal fluid and on catheter pieces with inflammatory reaction in the brain parenchyma was analyzed quantitatively. RESULTS: Sterile and infected Ag-PP-g-PEG-covered groups revealed significantly lower bacteria colony count on the catheter surface (ANOVA, 0 ± 0, p < 0.001; 1.08 ± 0.18, p < 0.05, respectively). There was moderate inflammatory response in the parenchyma in group 4, but in groups 5 and 6, it was similar to that of the sterile group (ANOVA, 16.33 ± 3.02, p < 0.001; 4.00 ± 0.68, p < 0.001, respectively). CONCLUSIONS: The PP-g-PEG, especially Ag-PP-g-PEG polymer-coated ventricular catheters are more effective in preventing the catheter-related infection and created the least inflammatory reaction in the periventricular parenchyma.

Bilateral middle cerebral artery aneurysms: a comparative study of unilateral and bilateral approaches.

The best surgical method for the treatment of patients with bilateral middle cerebral artery (bMCA) aneurysms has not been fully determined yet. The main purpose of this study is to compare the surgical results of unilateral and bilateral approaches to bMCA aneurysms including mean operation time, mean hospital stay, and mean cost, in the experience of the same neurosurgical team. Between January 2001 and June 2010, 22 patients with bMCA aneurysms were surgically treated in our institution. In 12 cases (54.5 %), ipsilateral and contralateral MCA aneurysms were successfully clipped via unilateral approach. In the remaining 10 cases, bilateral approach was necessary because of some technical difficulties. Although the surgical results were almost the same, mean operation time and mean hospital stay were, respectively, 46 and 37 % shorter and mean cost per person was 23 % lower for the patients in the unilateral group. In addition, the severity of brain edema, total length of the contralateral (A1+M1) segment, and the configuration of contralateral aneurysm were found to be the determinant parameters affecting the feasibility of the unilateral approach. To our knowledge, this is the first study in the literature that compares the clinical outcomes of unilateral and bilateral approaches to bMCA aneurysms. The results of surgery for both approaches are almost the same. However, the unilateral approach has certain advantages compared to the bilateral approach. Therefore, the unilateral approach may be a good alternative in surgical management of patients with bMCA aneurysms in selected cases and the abovementioned parameters can help the neurosurgeon in patient selection.

Comparison of intrathecal cilostazol and nimodipine treatments in subarachnoid hemorrhage: an experimental study in rabbits.

OBJECTIVE: intrathecal administration of calcium channel antagonists has been proposed to reduce cerebral vasospasm (CVS) in animal subarachnoid hemorrhage (SAH) models. Also, delayed CVS treatment model with oral administration of cilostazol can be seen in the literature. METHODS: in this study, 25 male New Zealand white rabbits were randomly assigned to five groups: control, SAH only, SAH/nimodipine, SAH/cilostazol, SAH/vehicle. The animals' basilar arteries were sectioned from four separate zones and four sections were obtained from each rabbit. Basilar artery luminal section areas were measured by using SPOT for windows Version 4.1 computer program. RESULTS: basilar artery luminal section areas in SAH/ nimodipine and SAH/ cilostazol groups were significantly higher than SAH only group (P < 0.05). CONCLUSION: phosphodiesterase 3 inhibitor cilostazol has vasodilatory effects without affecting cerebral blood flow. Nimodipine is a calcium channel blocker and is still used in vasospasm therapy either oral or intravenously. This study demonstrates that prophylactic bolus intrathecal administration of either cilostazol or nimodipine equally prevents SAH-associated CVS in an animal model. We therefore propose that cilostazol is a candidate for clinical trials in the treatment of delayed vasospasm.

Effects of intramuscular parecoxib administration on vasospasm in an experimental subarachnoid hemorrhage model.

AIM: We examined whether intramuscular parecoxib administration has a preventive or therapeutic effect on vasospasm following experimental subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: Twenty New Zealand White Rabbits were assigned randomly to one of four groups. Animals in Group I were not subjected to SAH (control group). Animals in all other groups were subjected to SAH. Animals in Group II received no treatment after SAH induction (SAH group). Animals in Group III received intramuscular parecoxib (diluted with saline) injection at 6 and at 30 hours after SAH (treatment group). Animals in Group IV received only intramuscular saline injection at 6 and at 30 hours after SAH (vehicle group). Animals were euthanized by perfusion and fixation 48 hours after SAH induction. Basilar artery cross-sectional areas and wall thicknesses were measured. Statistical comparisons were performed using Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Basilar artery cross-sectional areas in the treatment group were significantly higher than in the SAH or vehicle group (p<.05). Basilar artery wall thickness in the treatment group was significantly smaller than in the SAH or vehicle group (p<.05). CONCLUSION: Our study revealed that intramuscular administration of parecoxib significantly attenuates vasospasm following experimental SAH.

Aspiration or capsule excision? Analysis of treatment results for brain abscesses at single institute.

AIM: Aspiration of the abscess cavity versus excision of capsule are still in debate for the capsulated, large, superficially located abscesses. MATERIAL AND METHODS: Twenty patients who had large, solitary, capsulated, and superficially located lobar abscesses were analyzed retrospectively to compare the efficiency of two different surgical approaches and their impact on postoperative antibiotic use and the length of hospital stay. RESULTS: Nine patients underwent the capsule excision and 11 patients had the aspiration of their abscesses. There were no differences in terms of age, sex, location of abscesses, and radiographic features. There were 3 residual/recurrence in the aspiration group, who needed a second aspiration whereas; no residual/recurrence was observed in the excision group. Postoperative utilization of antibiotics was significantly less in the excision group (Mean: 26.7 days in the excision group vs. 46.6 days in aspiration group). Length of hospital stay for the purpose of iv antibiotic administration was significantly shorter in the excision group in close correlation with iv antibiotic use. CONCLUSION: Our study demonstrated that excision of abscess capsule was superior to aspiration in terms of efficiency of surgical intervention and postoperative cost of the treatment in a highly selected group of brain abscesses.

The effects of intravenous cilostazol and nimodipine on cerebral vasospasm after subarachnoid hemorrhage in an experimental rabbit model.

AIM: Our aim in this study was to investigate the efficacy of intravenous administration of cilostazol and compare these effects with intravenous usage of nimodipine in subarachnoid hemorrhage model. MATERIAL AND METHODS: Twenty-five male New Zealand White rabbits were assigned randomly to 1 of 5 groups. Animals in group 1 (n=5) served as controls, group 2 (n=5) was the SAH-only group, group 3 (n=5) was treated with intravenous 10 mg/kg cilostazol, group 4 (n=5) was treated with 0.05 mg/kg intravenous nimodipine, and group 5 (n=5) served as the vehicle group and treated with a mixture of dimethyl sulfoxide and phosphate buffer solution. Basilar arteries were removed from the brain stems and analyzed. The vessels were measured using computer-assisted morphometry (SPOT for Windows Version 4.1). Statistical comparisons were performed using the Kruskall-Wallis and Mann-Whitney U tests. RESULTS: Basilar artery wall thicknesses in group 3 and 4 were smaller than the group 2 and this was statistically significant at p < 0.05. The mean arterial cross-sectional areas in group 3 and 4 were higher than group 2 and this was also statistically significant at p < 0.05. CONCLUSION: Our results demonstrate that intravenous administration of both cilostazol and nimodipine significantly attenuates cerebral vasospasm after SAH.

Distal anterior choroidal artery aneurysms.

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.

Thalamomesencephalic ossified cavernoma presenting with Holmes' tremor.

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.

Effect of erythropoietin on brain tissue after experimental head trauma in rats.

BACKGROUND: The purpose of this study was to investigate the effect of EPO on LPO, on ultrastructural findings, and on antiapoptotic bcl-2 and survivin gene expressions after TBI. The authors also compared the activity of EPO with that of MPSS. METHODS: Wistar rats were divided into 6 groups: sham-operated, control, moderate TBI-alone (300 g/cm), TBI + EPO-treated (1000 IU/kg), TBI + MPSS-treated (30 mg/kg), and TBI + vehicle-treated (0.4 mL albumin solution) groups. RESULTS: Compared with the levels in control and sham-operated animals, LPO was significantly elevated in rats in the trauma-alone group. The administration of EPO and MPSS significantly decreased the LPO levels (P < .05). Trauma also increases the antiapoptotic bcl-2 gene expression significantly at 24 hours postinjury (P < .05), but it has no effect on survivin expression. The EPO and MPSS treatments caused significant elevation in both gene expressions (P < .05). It is also showed that MPSS has more protective effect than EPO on brain ultrastructure, especially on the structure of small- (P < .05) and medium-sized myelinated axons, after TBI. CONCLUSIONS: EPO has protective effects after moderate TBI, and this effect seems better than MPSS on antiapoptotic gene expression and LPO. The protection of cerebral subcellular organelles after traumatic injury is more prominent in MPSS-treated animals than EPO-treated animals quantitatively. This experimental study indicates that the benefits of EPO in the management of TBI have promising results and prompts further studies on the difference between EPO and MPSS in histopathological findings at the subcellular level.

Effect of raloxifene on cerebral vasospasm following experimental subarachnoid hemorrhage in rats.

The effect of raloxifene on cerebral vasospasm following experimental subarachnoid hemorrhage (SAH) was investigated in a rat model. Seven groups of seven rats underwent no SAH, no treatment; SAH only; SAH plus vehicle; SAH plus 3 days intraperitoneal raloxifene treatment; SAH plus 4 days intraperitoneal raloxifene treatment; SAH plus 3 days intrathecal raloxifene treatment; and SAH plus 4 days intrathecal raloxifene treatment. The basilar artery cross-sectional areas were measured at 72 or 96 hours following SAH. The results showed raloxifene decreased SAH-induced cerebral vasospasm in all treatment groups, and suggested no difference between intraperitoneal and intrathecal application, or between 3 days and 4 days of raloxifene treatment. The present study demonstrates that raloxifene is a potential therapeutic agent against cerebral vasospasm after SAH.

Comparative dural closure techniques: a safety study in rats.

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.

Multiple aneurysms of the anterior communicating artery: radiological and surgical difficulties.

OBJECT: Multiple aneurysms of the anterior communicating artery (ACoA) occur rarely and have not been well investigated previously. The authors report on a consecutive series of six patients who each harbored multiple ACoA aneurysms. The radiological and surgical difficulties encountered in treating these complex and uncommon aneurysms are described and the pertinent literature is reviewed. METHODS: Between October 1996 and August 2003, the authors surgically treated 146 patients with ACoA aneurysms. Six (4.1%) of these patients harbored multiple aneurysms of the ACoA. Four of these patients were men and two were women; their ages ranged from 36 to 72 years. Five patients had two aneurysms and one patient had three. All underwent surgery performed using the pterional approach. The clinical presentations, angiograms, intraoperative difficulties, and surgical results were retrospectively analyzed. All patients had premorbid hypertension. In two cases, the aneurysms were initially misdiagnosed as a single complex aneurysm based on routine cerebral angiograms, but special angiographic views demonstrated double aneurysms. In one case, multiple ACoA aneurysms could be identified using three-dimensional (3D) computerized tomography (CT) angiography. The size of the ACoA aneurysms ranged from 3 to 12 mm (mean 5.3 mm). A total of 13 ACoA aneurysms were successfully occluded in the six patients. Four patients were discharged in good condition, and two patients died. CONCLUSIONS: Although multiple ACoA aneurysms are quite rare, the following points should be kept in mind. (1) In bilobular ACoA aneurysms, special angiographic projections and 3D CT angiography or 3D digital subtraction angiography should also be performed to obtain a correct diagnosis. The differentiation of two aneurysms from a bilobular aneurysm during the preoperative period is important for surgical planning. (2) Angiographically, detection of the ruptured aneurysm is often difficult. (3) Resection of the gyrus rectus is necessary to obtain a good operative exposure. 4) Clip selection and sequencing are important. Straight clips with short blades should be preferred to avoid narrowing of the surgeon's view and a collision between the clips.

Rare cause of subarachnoid hemorrhage: spinal meningeal carcinomatosis. Case report.

Subarachnoid hemorrhage (SAH) of spinal origin is a rare entity accounting for approximately 1% of all cases of SAH. Its most frequent causes are trauma and vascular malformations. Although primary spinal tumors, especially ependymomas, are also relatively common causes, SAH secondary to a metastatic spinal tumor arising from outside the central nervous system is an extremely rare condition; only one case has been reported in the literature. The authors present a case of spinal meningeal carcinomatosis secondary to cutaneous malignant melanoma in which the patient presented with only symptoms of SAH. Although very rare, this case underscores several factors. 1) Spinal SAH due to spinal metastases should be considered in the differential diagnosis of patients with previously known malignancy. 2) Spinal SAH may manifest without paraparesis or sensory deficit. 3) Magnetic resonance imaging of the spinal cord may be important to determine the source of SAH in patients in whom four-vessel cerebral angiography demonstrates no abnormal findings.

Proposed classification of segments of the internal carotid artery: anatomical study with angiographical interpretation.

The nomenclature and borders of the segments of the internal carotid artery (ICA) remain confusing. A classification of segments of the ICA is proposed based on constant anatomical structures, such as the carotid foramen and canal, the petrous bone, the petrolingual ligament (PLL), and the proximal and distal dural rings. The bilateral ICAs were dissected in 15 cadaveric head specimens using different neurosurgical approaches. The bilateral lacerum foramina were studied in five dry skulls. The bilateral segments of the ICA were also examined on carotid angiograms of 10 normal patients and another with the ophthalmic artery originating from the intracavernous portion of the ICA. The present classification divides the ICA into five segments in the direction of the blood flow. The cervical segment is extradural and extracranial, the petrous segment is extradural and intraosseous, the cavernous segment is interdural and intracavernous, the clinoidal segment is interdural and paracavernous, and the cisternal segment is intradural and intracisternal. The ICA did not pass through the lacerum foramen in any specimen. In all specimens, 1/8 to 5/8 of the lacerum foramen was under the deep dural layer of the cavernous sinus. The term 'lacerum segment' as used previously and called the 'trigeminal segment' by us cannot be justified. The PLL is the posterolateral border of the cavernous sinus and the lacerum and trigeminal segments should be included in the cavernous and petrous segments. The ophthalmic artery may originate from the clinoidal ICA, from the cavernous ICA, or from the middle meningeal artery. Instead of using the term 'ophthalmic segment,' the term 'cisternal segment' should be used for the anatomically distinct ICA in the subarachnoid space. This classification should be minimally affected by anatomical variations.

Treatment of internal carotid artery aneurysms with a covered stent: experience in 24 patients with mid-term follow-up results.

BACKGROUND AND PURPOSE: We present our preliminary experience, including mid-term angiographic and clinical follow-up results, with an alternative technique for the endovascular treatment of intracranial aneurysms in a series of patients. This new method, previously described in anecdotal case reports, consists of endovascular deployment of an artificial vessel graft (stent graft or covered stent) in the parent vessel to exclude the intracranial aneurysm sac from circulation. METHODS: Twenty-five internal carotid artery (ICA) aneurysms in 24 patients were successfully treated by using a Jostent coronary stent graft deployed in the parent artery across the aneurysm neck. All except four aneurysms were extradural, located in the petrous or cavernous portion of the ICA. The four intradural aneurysms were located in the carotico-ophthalmic region. Seventeen aneurysms in 16 patients occurred posttraumatically, secondary to motor vehicle accidents or surgical injury. RESULTS: Twenty-three aneurysms were immediately excluded from circulation after stent graft placement. In two aneurysms, a slow contrast material filling (endoleak) into the aneurysm cavity was observed immediately after treatment. One was thrombosed, as shown by late control angiography; in the other one, a second larger bare stent was used to appose the stent graft's distal end to the ICA wall, thus sealing the endoleak into the distal graft. No technical adverse event, including vessel dissection, vessel perforation, or thromboembolism, occurred with or without clinical consequence. No mortality or morbidity developed during or after the procedure, including the follow-up period. Two-year control angiography in one patient, 1.5-year control angiography in two patients, 1-year control angiography in six patients, and 6-month control angiography in 12 patients were performed, revealing reconstruction of the ICA with no aneurysm recanalization. All symptoms resolved after treatment in the patients who had initially presented with mass effect. CONCLUSION: Initial anatomic, clinical and mid-term follow-up results in this small series of patients are encouraging. This technique has been proved to have potential in the reconstructive treatment of intracranial aneurysms. Further research and development are needed to optimize the stent graft technology for the cerebrovascular system.

Radiation-induced malignant triton tumor associated with severe spinal cord compression. Case report and review of the literature.

Malignant triton tumor (MTT) is a variant of malignant peripheral nerve sheath tumors. The authors report a case of radiation-induced MTT in a patient with severe cervicothoracic cord compression and review the related literature. This 36-year-old man presented with pain and weakness in his left arm. His medical history was significant for a biopsy procedure involving the sampling of an aneurysmal bone cyst located at T1-3 near the left lung apex; this was performed 6 years prior to presentation and was followed by radiotherapy. Neurological examination demonstrated radicular findings involving the left C-8 and T-1 nerve roots. Neuroimaging studies revealed a large mass lesion extending from C-6 to T-2 along the vertebral column, invading the upper thoracic cavity and the adjacent lung apex, and infiltrating the paravertebral muscles. A subtotal resection was performed, but the tumor regrew extensively within a short time. It invaded the spinal canal and caused significant cord compression. The patient underwent surgery two more times for tumor debulking and to relieve progressive airway and spinal canal compromise. He eventually became quadriplegic, however, and died 13 months after diagnosis of MTT. This is the seventh case of radiation-induced MTT and the fifth of MTT with spinal canal involvement to be reported in the literature.

Acute parotitis following sitting position neurosurgical procedures: review of five cases.

Acute bacterial parotitis subsequent to major abdominal surgery is well documented, reportedly occurring in as many as 0.1% of patients. Postoperative parotitis has been reported between 1 to 15 weeks after surgery, commonly appearing within 2 weeks of the procedure. However, postoperative parotitis has not been reported previously after neurosurgical procedures. The authors report five cases of postoperative parotitis after neurosurgical operations in the sitting position with mild flexion and rotation of the head. This group of patients accounted for 0.16% of all craniotomy and 1.9% of all sitting position neurosurgical procedures performed in the authors' institution from 1996 through 2001. Neck flexion and head tilt in the sitting position might have an influence on acute parotitis. The authors found that the side of the parotitis was on the opposite side of the head rotation. Dehydration therapy may also be a contributing factor. The objective of this paper is to state that parotitis is a possible complication in neurosurgical patients operated on in sitting position and to discuss its pathophysiology and treatment options.

Spinal dural arteriovenous fistula and venous aneurysm: an unusual association.

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.

Intracavernous granular cell tumor.

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.

The trigeminal nerve and ganglion: an anatomical, histological, and radiological study addressing the transtrigeminal approach.

BACKGROUND: The transtrigeminal route with splitting of the trigeminal ganglion (TG) is a skull base approach used to expose the posteromedial part of the cavernous sinus (CS), the base of the TG, and the petrolingual ligament (PLL). METHODS: To verify the transtrigeminal approach (TTA), the 3 divisions of the trigeminal nerve (TN), the so-called TG, and the trigeminal root were analyzed anatomically, histologically, and radiologically. The anatomic study was performed bilaterally in 5 cadaveric head specimens. For the histologic study, 6 TN specimens removed from cadavers were used. In addition, the radiologic demonstration of the TN and its so-called ganglion was performed on 5 cases by magnetic resonance imaging (MRI) scan. RESULTS: The TN is composed of linear, crossing, and connecting rootlets. These 3 types of rootlets indicate a plexiform constitution rather than a ganglion even though there are ganglionic cells. Consequently, the term "trigeminal plexus" may be preferred to describe this network. In our new proposed classification, the segments of the TN can be divided into 6 portions according to their relationship with the brainstem, the cisterns, and the bone structures. The first 3 segments before separating into 3 divisions are (1) pontine, (2) cisternal (preganglionic or preplexal), (3) gasserian (ganglionic or plexal). The last 3 segments after the division are (4) preforamino-fissural (postganglionic or postplexal), (5) foramino-fissural, and (6) extracranial (postforamino-fissural). A loose connective tissue along the rootlets of the maxillary and the mandibular divisions of the TN at the gasserian (ganglionic or plexal) segment enabled us to split the so-called "trigeminal ganglion" or "gasserian ganglion" to perform the TTA. CONCLUSION: The TTA is possible, useful, and necessary in selected cases with invasion of the posteromedial part of the CS.