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Objective: To study the safety and accuracy of ventriculostomy by neurosurgical trainees., Methods: Initial computed tomographic studies of 346 consecutive patients who underwent bedside ventriculostomy were reviewed retrospectively. Diagnosis, catheter tip location, midline shift, and procedural complications were tabulated. To analyze catheter placement, we used a new grading system: Grade 1, optimal placement in the ipsilateral frontal horn or third ventricle; Grade 2, functional placement in the contralateral lateral ventricle or noneloquent cortex; and Grade 3, suboptimal placement in the eloquent cortex or nontarget cerebrospinal fluid space, with or without functional drainage. Statistical analysis was performed using Fisher's exact test and a weighted kappa coefficient., Results: Diagnoses included the following: subarachnoid hemorrhage, n = 153 (44%); trauma, n = 64 (18%); intracerebral hemorrhage/intraventricular hemorrhage, n = 63 (18%); and other, n = 66 (20%). There were 266 (77%) Grade 1, 34 (10%) Grade 2, and 46 (13%) Grade 3 catheter placements. Hemorrhagic complications occurred in 17 (5%). Four patients (1.2%) were symptomatic, with two (0.6%) requiring surgery. Inter- and intraobserver agreement was almost perfect (kappa = 0.846 and 0.922, respectively) as applied to our grading system. Rates of suboptimal placement were highest in patients with midline shift (P = 0.059) and trauma (P = 0.0001). Rates of optimal placement were highest in patients with subarachnoid hemorrhage (P = 0.003) and when the catheter was placed ipsilateral to the side of midline shift (P = 0.063). Neither the resident's training experience nor the side of placement seemed to affect accuracy., Conclusion: Bedside ventriculostomy is a safe and accurate procedure for intracranial pressure monitoring and cerebrospinal fluid drainage.

Objective: The duration of fluoroscopy exposure is routinely recorded as part of endovascular procedures. However, to better relate the duration of exposure to actual doses of surface and intracranial radiation, we compared surface doses during endovascular procedures with intracranial doses in a cadaver model exposed to lateral fluoroscopy., Methods: Optically stimulated luminescence dosimeter chips (Landauer, Glenwood, IL) were used to measure the cranial surface dose of three consecutive patients undergoing endovascular procedures. Bitemporal craniotomies were performed on a cadaver. Dosimeter chips were placed on both the ipsilateral and contralateral skin and meningeal surfaces, and the cadaver was exposed to lateral fluoroscopy. Finally, to assess mean fluoroscopy times in patients undergoing embolization procedures, the operative notes of 100 consecutive patients were reviewed., Results: Three patients undergoing endovascular treatment received peak doses of 0.24, 0.31, and 1.38 Gy, respectively. In the cadaver, the peak surface dose recorded after 120 minutes of exposure was 1.71 Gy. The cranium and scalp absorbed or reflected 29% of the surface dose. Time in minutes of fluoroscopy was found to correlate with surface dose (R2 = 0.925)., Conclusion: Our data show that radiation exposure during endovascular treatment can reach clinically significant levels. The surface doses recorded during this study were comparable to the mean dose of 1.5 Gy estimated by others to increase the relative risk of inducing meningiomas, gliomas, and nerve sheath tumors. Pending long-term follow-up of patients exposed to endovascular procedures, consent for possible long-term sequelae of radiation may be warranted.

Objective: We examined the surgical approaches used at a single institution to treat petroclival meningioma and evaluated changes in method utilization over time., Methods: Craniotomies performed to treat petroclival meningioma between September of 1994 and July of 2005 were examined retrospectively. We reviewed 46 patients (mean follow-up, 3.6 yr). Techniques included combined petrosal or transcochlear approaches (15% of patients), retrosigmoid craniotomies with or without some degree of petrosectomy (59% of patients), orbitozygomatic craniotomies (7% of patients), and combined orbitozygomatic-retrosigmoid approaches (19% of patients). In 18 patients, the tumor extended supratentorially. Overall, the rate of gross total resection was 43%. Seven patients demonstrated progression over a mean of 5.9 years. No patients died. At 36 months, the progression-free survival rate for patients treated without petrosal approaches was 96%. Of 14 patients treated with stereotactic radiosurgery, none developed progression., Conclusion: Over the study period, a diminishing proportion of patients with petroclival meningioma were treated using petrosal approaches. Utilization of the orbitozygomatic and retrosigmoid approaches alone or in combination provided a viable alternative to petrosal approaches for treatment of petroclival meningioma. Regardless of approach, progression-free survival rates were excellent over short-term follow-up period.

Objective: To describe an alternative method of clip reconstruction and wrapping of fusiform aneurysms that provides structural support for the reconstructed parent artery or residual aneurysm., Clinical Presentation: A 57-year-old woman with an unruptured distal middle cerebral artery fusiform aneurysm underwent surgical treatment via a pterional craniotomy., Technique: A right-angled titanium clip was used to obliterate the aneurysm and to clip reconstruct the parent vessel, which was composed of a single inflow and outflow vessel. After the aneurysm was decompressed with a fine-gauge needle, the remnant/parent artery was wrapped with a thin layer of muslin gauze followed by circumferential application of the Gore-tex (W.L. Gore and Associates, Inc., Flagstaff, AZ) sling. Finally, a second right-angled aneurysm clip was applied to the free ends of the sling immediately adjacent to the parent vessel while the sling was cinched against the parent vessel. This maneuver allowed the Gore-tex material to buttress the reconstructed vessel circumferentially., Conclusion: Clip reconstruction with a Gore-tex sling preserves the parent vessel and simultaneously buttresses the reconstructed vessel wall with radial forces provided by the Gore-tex material. This method is a novel alternative to conventional methods for the treatment of fusiform aneurysms.

Because radiographic visualization of a pituitary microadenoma is frequently difficult, we hypothesized that microadenomas associated with Cushing's disease may be better resolved and localized via acquisition with 3-Tesla (3T) compared with standard 1.5-Tesla (1.5T) magnetic resonance imaging (MRI). Five patients (four females, one male; age range, 14 to 50 years old) with endocrine and clinical confirmation of Cushing's disease underwent 1.5T and 3T MRI and corticotropin-releasing hormone stimulation/inferior petrosal sinus sampling (IPSS) as part of their preoperative evaluation. All patients underwent a transnasal trans-sphenoidal pituitary adenomectomy. In two cases, tumor could not be localized on either 1.5T or 3T MRI on the initial radiologist's review. In two other cases, the 1.5T images delineated the tumor location, but it was more clearly defined on 3T MRI. In a fifth case, the 1.5T MRI showed a probable right-sided adenoma. However, on both 3T MRI and at surgical exploration the tumor was localized on the left side. Therefore, in three of five cases, 3T MRI either more clearly defined tumors seen on 1.5T MRI or predicted the location of tumor contrary to the 1.5T images. IPSS identified the correct side of the tumor in two patients, an incorrect location in two patients, and was indeterminate in one patient. In certain cases 3T MRI is a new tool that may ameliorate imaging difficulties associated with adrenocorticotrophic hormone-secreting pituitary adenomas. Its role in the diagnostic evaluation of Cushing's disease will be better defined with further experience.

Objective: To determine the safety and efficacy of preoperative embolization of central nervous system tumors with n-butyl cyanoacrylate (NBCA) liquid adhesive., Methods: Over a 6-year period, 35 consecutive patients (12 women, 23 men; mean age, 42 yr; range, 6 mo-75 yr) with a central nervous system tumor underwent preoperative embolization with NBCA. Tumor type, location, endovascular and surgical treatment, percent of tumor embolization, estimated blood loss, and neurological deficits related to embolization were evaluated retrospectively., Results: One hundred feeding arteries were embolized (mean, 3 vessels/patient). In only one (3%) case was a normal artery inadvertently occluded by the embolization. During the follow-up period, the resulting neurological deficit resolved completely. There were no neurological deficits or inadvertent embolization events in the remaining 34 cases. The mean percent of tumor embolized was 68%, but this did not significantly correlate with operative blood loss (Pearson's correlation coefficient, r = 0.049)., Conclusion: In experienced hands, central nervous system tumors can be embolized with NBCA liquid adhesive with a high degree of safety and efficacy. We think that adroit embolization technique with NBCA and other embolisates should be part of the contemporary neuroendovascular armamentarium.

Objective: To stratify the risk of embolization during the treatment of cerebral arteriovenous malformations (AVMs) by grade and to assess its impact on the overall treatment risk., Methods: Patients with cerebral AVMs treated with embolization between 1995 and 2004 were retrospectively reviewed. Age, sex, AVM grade, location of lesion, number and location of embolized arteries, and number of embolization sessions were analyzed with respect to neurological or vascular complications after embolization., Results: Embolization was performed in 153 patients: 508 vessels were embolized during 203 sessions (mean, 3.3 vessels per patient). The mean angiographic and clinical follow-up periods were 1.7 and 2.1 years, respectively (range, 3-60 mo). The periprocedural morbidity and mortality rate was 11.8%, but at the last follow-up examination, only 2% of survivors were significantly disabled (modified Rankin score > 2). One (0.7%) patient died, and 17 patients experienced unexpected neurological deficits immediately after embolization. Five of these patients demonstrated near or total recovery during follow-up. The number of branches embolized was the only variable significantly related to neurological deficit (P < 0.017). The long-term rates of neurological deficits after embolization were 0, 5, 7, 10, and 18%, respectively, for AVM Grades I through V. Among 114 patients who underwent preoperative embolization, follow-up deficit rates of Grades I through V were 0, 5, 6, 6, and 25%, respectively. Long-term permanent deficits from embolization occurred in 8.6% of patients., Conclusion: Endovascular treatment carries a procedural risk related to AVM grade and number of branches treated. This risk should be weighed carefully in the context of overall treatment morbidity and mortality.

Objective and Importance: Distal coil migration is a rare but hazardous complication of aneurysm coil embolization. Various microsnare devices have been developed to address this problem. We describe the surgical management of a case in which microsnare retrieval failed., Clinical Presentation: A 34-year-old woman presented with subarachnoid hemorrhage. Magnetic resonance imaging, computed tomography angiography, and conventional angiography showed an approximately 2.5-mm ophthalmic artery aneurysm. Using balloon remodeling, a 2 x 4-cm coil was deployed into the aneurysm fundus. While the coil pusher was being removed after deployment, the microcatheter advanced abruptly into the aneurysm. The coil mass was dislodged and migrated into the angular branch of the middle cerebral artery. Contrast extravasation was noted during attempted retrieval with a microsnare device., Technique: Computed tomographic scans showed a subarachnoid hemorrhage in the territory of the left frontotemporal operculum. A left modified orbitozygomatic approach was performed. The coil mass was removed from the angular artery and a thromboembolectomy was performed. The artery was repaired and the pseudoaneurysm was clip ligated. The ophthalmic artery aneurysm was clip ligated. The patient recovered without deficits., Conclusion: Distal coil migration and arterial perforation can be treated surgically with a good clinical outcome.

Objective: Olfaction is often sacrificed to gain access to the cranial base in anterior craniofacial surgery. We describe the long-term results of olfactory function in patients who underwent anterior craniofacial surgery and a cribriform plate osteotomy to preserve olfaction., Methods: Between 1992 and 2004, 28 patients underwent 29 cribriform plate osteotomies in an attempt to preserve olfaction during anterior craniofacial surgery performed through modified extended transbasal approaches. Patients' charts and office notes were reviewed retrospectively. Formal olfactory testing was available in 5 patients, but most data were based on patients' subjective reports of olfaction. Olfactory preservation was defined by the subjective ability to detect fumes such as coffee, chocolate, roses, and orange juice regardless of the intensity of the sensation. Follow-up was based on phone calls to patients., Results: Four patients were lost to follow-up and excluded. Therefore, follow-up was available in 24 patients after 25 procedures. On the basis of patients' subjective reports, olfaction was spared in 22 patients after 23 procedures (92%) and was confirmed objectively in the five patients formally tested. After surgery, only two patients were anosmic., Conclusion: Olfaction can be preserved in selected patients undergoing anterior craniofacial surgery. At least 1 cm of nasal mucosa should remain attached to the cribriform plate, which can be achieved by including the nasal bone in the osteotomy of the orbital bar. A medial orbital canthopexy is therefore necessary after these procedures.

Recurrent aneurysms of the anterior circulation that are distal to the anterior communicating artery (ACoA) but proximal to the callosomarginal-pericallosal bifurcation can pose a treatment challenge. The authors present one such case, in which the patient was treated with pericallosal artery-pericallosal artery (PerA-PerA) side-to-side bypass, followed by endovascular obliteration of the proximal A2 parent vessel. This patient, in whom an ACoA aneurysm had been treated with clip ligation 5 years previously, presented with a new, mid-A2, right-sided aneurysm with the outflow artery arising from the dome of the lesion. The treatment plan included two steps: an interhemispheric transcallosal approach for PerA-PerA side-to-side anastomosis; and endovascular coil embolization of the right A2 branch feeding the aneurysm. Postprocedure angiography demonstrated no ipsilateral aneurysm filling and excellent bilateral distal outflow from the anterior cerebral artery (ACA). The use of PerA-PerA side-to-side bypass for the treatment of an ACA aneurysm, followed by parent vessel occlusion, offers an elegant solution for the treatment of A2 aneurysms that are not amenable to stand-alone clip ligation or coil occlusion. Such combined methods are invaluable in the management of complex cerebral aneurysms.