follow-up period was 3.5 years (range 1 to 7.5 years). Surgical Technique The current surgical approach used by the neurovascular service emphasizes six fundamental concepts. 1) The preservation of CBF during and after the operation is critical. Therefore, all patients are monitored with intraoperative electroencephalography. 51 Furthermore, patients with large tumors in whom temporary carotid artery occlusion may be required have baseline preocclusion and occlusion xenon-133 ( 133 Xe) CBF studies. 2) Distal exposure of large tumors is obtained by mobilization
Fredric B. Meyer, Thoralf M. Sundt Jr. and Bruce W. Pearson
Jamie J. Van Gompel, Jesus Rubio, Gregory D. Cascino, Gregory A. Worrell and Fredric B. Meyer
outcome of these 2 basic approaches: in cases of temporal lobe cavernomas, does ECoG alter the surgical approach or outcome? Furthermore, in temporal lobe cavernomas, does lesionectomy as opposed to more aggressive therapies (most often formal lobectomies) alter seizure outcome? We have analyzed our experience to answer these questions. Methods Inclusion Criteria The Mayo Clinic medical and surgical index databases were searched from 1971 to July 2006, and 173 surgically removed cavernomas were identified. Among these 173 cases were 105 patients who had
Fredric B. Meyer and Jeffrey N. Bruce
This edition of the Video Supplement entitled “Microsurgery of the Third Ventricle, Pineal Region, and Tentorial Incisura” highlights approaches to accessing the third ventricle for surgical resection of a variety of pathologies. The third ventricle has critical neurovascular anatomy that must always be respected to prevent patient harm. Visualization of critical anatomy in three dimensions from a surgeon' line of sight is important when planning the optimum surgical approach. Some of the keys to safely operating in this region include thoughtful head positioning, limitation of brain retraction, and the use of trajectories which capitalize on CSF cisterns and fissures. Some of the videos included in this volume illustrate standard operations while others depict more unique and innovative approaches that take advantage of these surgical windows. We hope you enjoy the videos included in this supplement.
Cormac O. Maher, James A. Garrity and Fredric B. Meyer
Ventriculoperitoneal (VP) shunts have not been widely used for idiopathic intracranial hypertension (IIH) because of the difficulty of placing a shunt into normal or small-sized ventricles. The authors report their experience with stereotactic placement of VP shunts for IIH.
The authors reviewed the clinical records of all patients in whom stereotaxis was used to guide the placement of a VP shunt for IIH at their institution. All shunts were placed using stereotactic guidance to target the frontal horn of the lateral ventricle. Patients were contacted at a mean postoperative interval of 15.1 months. No patients were lost to follow up.
The authors identified 13 patients who underwent placement of a stereotactically guided VP shunt for IIH over a 6-year period. A trial of either acetazolamide or steroid therapy had failed in all patients. Prior surgical treatments included optic nerve sheath fenestrations in seven patients and cerebrospinal fluid diversionary procedures, other than stereotactic VP shunt procedures, in nine patients. Twelve patients reported excellent or good durable symptomatic relief at the time of follow up. No patient suffered progression of visual deficits. Four patients experienced persistent headaches following the procedure. Three patients required a revision of the VP shunt for technical failure.
Stereotactically guided VP shunt placement is an effective and durable treatment option in many cases of IIH that are refractory to more traditional medical and surgical approaches.
Jamie J. Van Gompel, W. Richard Marsh, Fredric B. Meyer and Gregory A. Worrell
procedure in the literature. 5 , 12 , 20 , 22 This is likely due to the ongoing debate as to the extent of tissue surrounding the cavernoma that needs to be removed to achieve the best outcome for the patient. 2 , 5 , 12 , 19 , 20 , 22 Ultimately, approximately 90% of patients realize a decrease in seizure frequency and 60% to 90% achieve seizure freedom depending on the surgical approach used. 2 , 5 , 7 , 12 , 13 , 15 , 19 , 20 Interestingly, 87% of our survey responders were seizure free, which is imperative when one considers the average follow-up interval of more
Brian A. Iuliano, Robert E. Anderson and Fredric B. Meyer
less cerebral damage than non-interrupted occlusion in a focal ischemic model. J Cereb Blood Flow Metab 13 (Suppl 1): S737, 1993 (Abstract) 39. Sundt TM Jr , Grant WC , Garcia JH : Restoration of middle cerebral artery flow in experimental infarction. J Neurosurg 31 : 311 – 322 , 1969 Sundt TM Jr, Grant WC, Garcia JH: Restoration of middle cerebral artery flow in experimental infarction. J Neurosurg 31: 311–322, 1969 40. Sundt TM Jr , Piepgras DG : Surgical approach to giant intracranial
Marc S. Goldman, Robert E. Anderson and Fredric B. Meyer
monkey. Effect on brain adenosine triphosphate and lactate levels with electrocortico-graphic and pathologic correlation. Circ Res 30: 703–712, 1972 35. Sundt TM Jr , Piepgras DG : Surgical approach to giant intracranial aneurysms. Operative experience with 80 cases. J Neurosurg 51 : 731 – 742 , 1979 Sundt TM Jr, Piepgras DG: Surgical approach to giant intracranial aneurysms. Operative experience with 80 cases. J Neurosurg 51: 731–742, 1979 36. Symon L , Vajda J : Surgical experiences with giant
Fredric B. Meyer, Daniela Lombardi, Bernd Scheithauer and Douglas A. Nichols
subtotal resection or as a primary treatment in the elderly or debilitated patient. A preoperative determination that the tumor is indeed intracavernous is necessary for successful tumor removal; this finding would alter the surgical approach decision in favor of medial sphenoid wing removal. For the more common medial sphenoid wing meningioma, removal of this bone is unnecessary. Therefore, the best diagnostic test for surgical planning is coronal MR imaging. In addition, preoperative angiography with trial balloon occlusion of the internal carotid artery is helpful
Ryan T. Merrell, S. Keith Anderson, Fredric B. Meyer and Daniel H. Lachance
complex partial 3 (12) 12 (23.5) 0.4627 generalized 14 (56) 23 (45.1) partial 8 (32) 16 (31.4) * All values given as number of patients (%) unless otherwise indicated. The surgical approach and the lobar and cortical distributions of tumors were approximately equal between cohorts. Similarly, the types of seizures were equally distributed. Approximately equal percentages of phenytoin- and levetiracetam-treated patients underwent biopsy versus resection (approximately 25% underwent biopsy in both groups vs approximately 75% who underwent
Fredric B. Meyer, Michael J. Ebersold and David F. Reese
case in which the patient died from a perforated duodenal ulcer. Although there are reports of tumor removal by an anterior transoral approach, 29 the surgical approach to all these tumors was from a posterior approach with the patient in a sitting position. Suboccipital craniectomy was then carried out, with removal of the lamina of C-1 and C-2. In 30% of the cases the roots of C-1 and C-2 were sacrificed to afford better exposure. Approximately 5.0% of the surviving patients were known to have died within 3 years of surgery from tumor recurrence. Review of the