ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

OBJECTIVEComputer-assisted frameless navigation techniques are used in many centers for intracranial neurosurgical procedures. In this study, we assessed the accuracy and the clinical usefulness of a frameless system based on the optical digitizer in a variety of intracranial procedures.METHODSThe optical digitizer (StealthStation, Sofamor Danek, Memphis, TN) was used to perform 170 neurosurgical operations. Its accuracy was judged before and after each operation by comparing the computer-estimated error with the real estimated error measured on the patient’s anatomy. Several objective factors were evaluated to assess the clinical usefulness of the optical digitizer. For craniotomies, the intraoperative extent of resection based on computer-generated images was compared with that on postoperative images, and the length of hospital stay of patients undergoing frameless procedures was compared with that of patients undergoing conventional procedures. For needle biopsies, clinical usefulness was based on the rate of success in establishing a histological diagnosis.RESULTSThe optical digitizer was accurate to within 2 mm for all procedures. The computer-estimated error was not significantly different from the real estimated error. The intraoperative extent of resection was accurate in 58 of 60 tumor resection patients, as confirmed on postoperative images. Patients undergoing frameless procedures had a significantly shorter hospital stay than those undergoing conventional procedures (7.5 ± 1 versus 10.8 ± 1.3 d,P< 0.05). All biopsies were diagnostic.CONCLUSIONThe optical digitizer is an accurate frameless device that offers clinical benefits. These include precise surgical resection, decreased hospitalization time, and accurate tissue diagnosis.

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

OBJECTIVETo evaluate the utility of performing transsphenoidal surgery with computer-assisted image guidance.METHODSThirty-seven patients underwent transsphenoidal surgery in which a frameless stereotactic system was used to confirm the trajectory to the sella and to locate the anatomic midline. This technique was compared with our standard method of using an image intensifier to confirm the approach (n = 43). The numbers of complications associated with the approach, the times required to set up and perform each operation, and the average costs for each group were compared.RESULTSThere were no complications attributable to inaccurate localization from the neuronavigational system. Additional setup time was necessary to calibrate and register the system; this represented a mean of 17 minutes in transsphenoidal procedures performed for the first time (n = 30), whereas reoperations required an average of 22 minutes (n = 7) (P< 0.05). The operative times, defined as time from incision to closure, were not statistically different (P= 0.38). To reduce assistant variation, a subset of this group in which the same assistant was used (n = 18) was analyzed. The additional setup time was reduced to a mean of 12 minutes (P< 0.05). The total case times were actually reduced in this group (127 versus 133 min), but this was not statistically significant (P= 0.75). Fluoroscopy was not required when frameless stereotaxy was used. The cost savings were partially offset by the cost of the preoperative computed tomographic study necessary for fiducial registration and the additional cost of setup time in the operating room. When all factors were analyzed, an additional cost to the patient of $318.00 was noted. The image guidance in axial, coronal, and sagittal planes provided by frameless stereotaxy was subjectively beneficial; it increased our confidence with the approach to the sella and intraoperative localization and was particularly helpful in reoperations where standard anatomic landmarks were distorted.CONCLUSIONFrameless stereotaxy is a technology that provides continuous, three-dimensional information for localization and surgical trajectory to the surgeon and can be applied to transsphenoidal surgery with minimal additional cost and time requirements.

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

OBJECTIVEThe reintroduction of pallidotomy for the treatment of Parkinson’s disease (PD) has generated various opinions regarding the ideal anatomic or physiological location of the target within the globus pallidus. The role of microelectrode recording guidance in pallidotomy for the treatment of advanced PD is presently under debate. The purpose of this study was twofold. The first goal was to determine the degree of accuracy in the targeting of the globus pallidus internus (GPi) with magnetic resonance imaging (MRI), by comparing these results with the final placement of the thermolytic lesions (as defined by electrophysiological assessment). The second goal was to ascertain the somatotopic arrangement of the GPi in PD.METHODSThe analysis involved 50 patients with PD who underwent microrecording-guided pallidotomy. The theoretical coordinates for lesioning were calculated after definition of the intercommissural line by MRI. The actual placement of the lesions was determined after mapping of the GPi by microrecording, using stimulation to identify the sensorimotor region and its somatotopic organization.RESULTSIn most cases, the lesions were placed posterior and lateral to the targets chosen by MRI. Mapping by microrecording revealed differences of 2.3 ± 1.55 mm and 3 ± 1.9 mm in the mediolateral and anteroposterior coordinates, respectively. The actual lesion overlapped the theoretical target for only 45% of the patients. The somatotopic organization of the GPi was analyzed. Most of the units with sensorimotor activity or tremor-related activity were in the lateral portion of the nucleus. Upper limb and axial units were in the most lateral region and mainly in the ventral one-third of the nucleus. Lower limb responses were recorded mainly in the dorsal one-third of the nucleus. Tremor-related cells were found throughout the sensorimotor region of the nucleus.CONCLUSIONThese results indicate that lesion targeting based on MRI alone is not sufficiently accurate to guarantee placement of the lesion in the sensorimotor region of the GPi.

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

OBJECTIVETo determine whether magnetic resonance imaging (MRI), compared with computed tomography (CT), provides consistent and accurate target localization for ventrolateral thalamotomy and posteroventral pallidotomy.METHODSFor 93 procedures (78 pallidotomies and 15 thalamotomies) in 83 patients, coordinates for the anterior commissure, posterior commissure, and stereotactic target were calculated from MRI- and CT-derived images and compared.RESULTSThe mean differences for the target were −0.41 mm on thexaxis (P< 0.001), 0.06 mm on theyaxis (P= 0.412), and −0.34 mm on thezaxis (P< 0.01). The mean absolute differences were 0.53 mm on thexaxis (median, 0.50 mm; range, 0.00–2.00 mm), 0.46 mm on theyaxis (median, 0.50 mm; range, 0.00–2.00 mm), and 0.78 mm on thezaxis (median, 0.50 mm; range, 0.00–6.00 mm). The mean three-dimensional distance between MRI- and CT-derived coordinates for the anterior commissure was 1.65 mm, with a distance of more than 4 mm in two cases (2%). The mean three-dimensional distance for the posterior commissure was 1.65 mm, with a distance of more than 4 mm in two cases (2%). The mean three-dimensional distance for the target was 1.25 mm (median, 1.14 mm; range, 0.00–6.27 mm), with a distance of more than 4 mm in one case (1%).CONCLUSIONStatistically significant but relatively small differences between MRI- and CT-derived target coordinates were found. In some cases (approximately 2% of this series), the differences between MRI- and CT-derived coordinates may be relatively large (greater than 4 mm and up to 8 mm). However, given the superior anatomic resolution of MRI and the nature of the stereotactic procedures under consideration, we conclude that MRI, when validated within an institution, may be used alone for target localization in pallidotomy and thalamotomy.

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

OBJECTIVEWe present two cases of common carotid artery occlusion that were treated by vascular reconstruction using the transverse cervical artery.METHODSTwo patients with common carotid artery occlusion presented with transient ischemic attacks resulting from decreased cerebral blood flow on the affected side. Both patients underwent vascular reconstruction using the transverse cervical artery. The transverse cervical artery was anastomosed to the ipsilateral external carotid artery at its origin, as a pedicle graft. A superficial temporal artery-middle cerebral artery anastomosis was then performed.RESULTSThe postoperative courses were uneventful. The transverse cervical artery bypass grafts were patent, and cerebral blood flow increased to normal levels.CONCLUSIONTransverse cervical artery grafting provides a less tedious alternative to saphenous vein interposition grafting for revascularization of the internal carotid artery domain.

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

OBJECTIVECorpus callosotomy is a surgical option for medically uncontrolled generalized epilepsy in appropriate patients. Because numerous complications related to open callosotomy are still reported, we performed radiosurgical corpus callosotomy with the gamma knife.METHODSBetween October 1992 and June 1995, three patients underwent stereotactic radiosurgery to ablate the anterior third of the corpus callosum. The patients had intractable epilepsy: two had Lennox-Gastaut syndrome, and one had multifocal epilepsy with atonic, tonicoclonic, and atypical absence seizures. The history of seizures ranged from 20 to 37 years’ duration. Stereotactic radiosurgery was performed with a cobalt-60 gamma knife using a 4-mm collimator, targeted to the rostrum, genu, and anterior third of body of the corpus callosum. Two patients were treated once with 150 and 160 Gy at maximum, respectively, and one patient was treated in two stages with 50 Gy and then 170 Gy at maximum.RESULTSThe severity and frequency of seizures were significantly reduced in all three patients. The types of seizures associated with the most improved outcome were atonic and generalized tonicoclonic seizures. The mean follow-up period was 38 months. Hospitalization required for this procedure was 3 days. No complications related to irradiation were recorded except transient headache in one patient.CONCLUSIONThe outcomes suggest that radiosurgical corpus callosotomy may be a promising alternative treatment to open callosotomy.

ISSN:0148-396X    

出版商:OVID    

年代:1999

数据来源: OVID