Neuronavigation and complication rate in epilepsy surgery

The role of neuronavigation for complications in temporal lobe epilepsy surgery was evaluated. Thirty-seven patients operated on with neuronavigation (group N: 38 operations; mean age 33.9 years; etiology: cryptogenetic 31, symptomatic 7; lateralization: 22 right, 16 left) and 22 patients operated on without neuronavigation (group NN: 23 operations; mean age 29.7 years; etiology: cryptogenetic 9, symptomatic 14; lateralization: 13 right; 10 left) were analyzed. The minimal follow-up time was 2 years. There was a clear difference in the number of complications (N 7.9%; NN 21.7%), which consisted of hemiparesis (N: 1; NN: 2), cranial nerve palsy (N: 1; NN: 2), aphasia (N: 1; NN: 0), and postoperative infection (N: 0; NN: 1). In addition, there was a reduced need for temporal re-resection after intraoperative electrocorticography (N 30.6%; NN 47.1%). Operation time (N: 239±9.4 min; NN: 208±12.1 min), duration of postoperative in-hospital and in-ICU stay [N: 16.9±1.1 days (1.0±0.0 days); NN: 17.2±2.8 days (1.1±0.1 days)], extension of temporal lobe resection from polar (N: 41.2±1.5 cm; NN: 42.9±3.9 cm), and postoperative seizure frequency reduction (N 90.4%; NN 94.7%) were not different. Because of the trend towards a reduction of complications and re-resections after electrocorticography, the authors recommend neuronavigation despite its higher costs as an additional tool in epilepsy surgery.     

Neuronavigation guided surgery for parenchymal neurocysticercosis in two patients

Summary Neurocysticercosis is a rare disease in the Baltic area while it is common in the endemic regions. Two patients with serologically negative parenchymal neurocysticercosis from our neurosurgical department who underwent extirpation of the cystic lesions with neuronavigation guided surgery are reported in this paper. Though most publications propose medical treatment with albendazole and praziquantel for parenchymal neurocysticercosis, surgery can be an option for diagnosis and treatment in conjunction with cysticidal medication if the diagnosis is unclear particularly in non-endemic areas.     

Neuronavigation and functional MRI for surgery in patients with lesion in eloquent brain areas.

OBJECTIVE: Surgery in patients with lesions in eloquent areas is still a challenge for the neurosurgeon. The aim of surgical interventions should be the radical removal of the lesions with functional preservation. Functional brain imaging methods provide the preoperative demonstration of those brain areas and their relationship to pathologic structures. MATERIAL: Twenty-seven patients with pathologic lesions in or near eloquent regions were investigated with functional magnetic resonance imaging (fMRI). Nineteen patients were neurologically intact preoperatively, and presented only with headache and/or seizure. Eight patients had a minor neurological deficit. Twenty-five patients underwent surgery. Preoperatively a computed tomography (CT) scan or a magnetic resonance imaging procedure with five skin fiducials was performed. The data were transferred to the neuronavigation workstation. The tumour was lined out in colours, and reconstruction in a triplanar format as well as three-dimensionally was implemented. The information from the fMRI concerning the functional areas was transferred into the images manually to account for EPI distortions. Fifteen patients were operated on using the combination fMRI/neuronavigation. Diagnoses included eleven gliomas, two meningeomas, one metastasis and one cavernoma. RESULTS: In seven patients the tumour was removed completely, eight patients had residual tumour, demonstrated by early postoperative MRI. All patients with residual tumour had gliomas that involved functional areas. Postoperatively no patient had an additional neurological deficit. CONCLUSION: Functional MRI provides important additional information in patients with lesions in eloquent brain areas. In combination with neuronavigation this is a very helpful technique for surgical interventions on these patients to reduce morbidity. Nonetheless, there are still open questions concerning accuracy of display of the functional areas and integration into a neuronavigation system.     

Anaesthesia for pituitary surgery

Surgical lesions of the pituitary gland, the majority of which are benign adenomas of the anterior lobe, present a varied and challenging spectrum of peri-operative anaesthetic problems. Successful management is based on a comprehensive understanding of the applied anatomy and physiology of the pituitary gland, the endocrine and neurosurgical consequences of pituitary adenomas and the specific implications of the chosen neurosurgical approach. The majority of pituitary adenomas can be resected adequately by an extracranial trans-sphenoidal approach, although transcranial resection may be necessary if the tumour has a significant suprasellar extension or if the diagnosis is in doubt. In general terms, pituitary surgery demands the same levels of peri-operative care as those required by intracranial surgery.     

Neuronavigation in intraoperative MRI.

OBJECTIVE: We describe the development and implementation of an image-guided surgical system combining the best features of conventional frameless stereotactic systems and the recently developed superconductive vertically configured intraoperative magnetic resonance scanner. The incorporation of intraoperatively updated magnetic resonance imaging (MRI) data sets into the neuronavigation computer overcomes one of the main disadvantages of these systems, i.e., intraoperative brain shift. METHODS: The integrated system consists of a 0.5-T MRI scanner (Signa SP General Electric Medical Systems, Milwaukee, WI), a neuronavigation computer with associated software (OTS Radionics, Burlington, MA), and an emulation program linking the two. The scanner has a 60-cm-wide vertical gap where both imaging and surgery are conducted, in-bore infrared linear cameras and monitors for interactive surgical neuronavigation, and flexible surface coils specially designed for surgery. RESULTS: Phantom studies showed navigational accuracy to be better than that obtained using conventional preoperative images and surface markers for patient registration. Our initial 17 cases using this integrated system comprised 16 craniotomies and one biopsy, and demonstrated decreased operative duration, greater frequency of interactive image guidance utilization, and better assessment of the progress of surgery compared to the cases previously done in the intraoperative MRI. CONCLUSION: This initial study of the addition of frameless stereotactic systems to the basic intraoperative MRI concept has demonstrated its clinical usefulness. The use of the intraoperative MRI greatly reduces the basic weakness of neuronavigation inaccuracy due to target shift. The surgical procedure performed in the imaging volume of the MRI scanner eliminates the problems of patient or scanner transport during the procedure. Immobilization of the patient throughout the procedure eliminated the need for reregistration of the patient, by taking advantage of the fixed camera system in the bore of the MRI system.     

Neuronavigation in third ventricle tumors

The authors present the results of neuronavigation as a help to open neurosurgery for the tumors of the third ventricle. From January, 1995 to August, 1999, six image-guided surgical procedures were performed to remove third ventricle lesions : 4 collo?d cysts, 1 ependymoma, and 1 craniopharyngioma. The operative approach was transcortical in 5 cases, and transcallosal in 1 case. The use of neuronavigation allows a decrease of the surgical trauma during the surgical approach. The procedure secures the neurosurgeon in the choice and execution of his pathway to the target. It becomes however less accurate after opening the ventricle, because of the brainshift induced by the loss of cerebrospinal fluid becomes important. Nevertheless, neuronavigation is useful in the surgery of the third ventricle, especially if it is used with neuroendoscopy.     

Neuronavigation in skull base tumors.

OBJECTIVE: Computer-assisted neuronavigation was used in 87 cases of skull base lesions (SBLs). Preoperative planning and intraoperative identification of anatomic landmarks is especially important in SBLs since it helps to avoid or minimize surgical morbidity and mortality. In this study, we assessed the accuracy and the clinical usefulness of a frameless system based on the optical digitizer in SBLs. PATIENTS AND METHODS: Between April 2000 and March 2003, eighty-seven patients with SBLs were operated on in our department using cranial neuronavigation. A passive-marker-based neuronavigation system was used for intraoperative image guidance. There were 56 women and 31 men. The patient's ages ranged from 4 to 76 years (average: 45.7 year). The locations of the tumors reported in this series were as follows: frontobasal, 24 cases; sellar/parasellar, 32 cases; petroclival, 16 cases; tentorial/subtemporal, 15 cases. RESULTS: The computer-calculated registration accuracy ranged between 0.3 and 1.7 mm (mean, 1.1 mm). Gross total removal of the SBLs was accomplished in 82 out of 87 patients as was confirmed on postoperative CT and MRI scans. The follow-up period ranged from 1 month to 48 months (average: 20.1 months). Overall mortality and severe morbidity (meningitis, permanent cranial nerve deficits, and cerebrospinal fluid fistulae) rates were 4.6 % and 33.3 %, respectively. CONCLUSION: The image-guided surgery is a valuable aid for safe, helpful and complete removal of SBLs of the brain where accurate localization of the lesion is critical. Although our preliminary series is not large, interactive image guidance provides a constant display of surgical instrument position during surgery and its relationship with the SBLs components, surrounding normal brain, and vascular structures, providing valuable guidance to the surgeon during an operation. Our experience with the neuronavigation suggests that image guidance is helpful in this type of lesions, providing better anatomic orientation during skull base surgery, delineating tumor margins and their relation to critical neurovascular structures.     

Microscope and endoscopic pituitary surgery

Having just celebrated the centenary of the first transsphenoidal pituitary operation by (Schloffer in Austria in Beitr Klin Chir 50:767–817, 1906), and this year the quarter centenary of the first published report of a therapeutic use of the neuroendoscope (for colloid cysts of the third ventricle) (Powell et al. in Neurosurgery 13:234–237, 1983), it is time to consider the relative merits of microscopic and endoscopic approaches for pituitary surgery. Although transsphenoidal endoscopic surgery has only been utilised by pioneers such as Jho since the mid-1990s (Jho et al., 1996), there is no doubt that it has already gained an important place in the neurosurgical armamentarium, but there is both confusion and propaganda about which method of surgery has most to offer, and indeed whether or not there is any real difference at all.     

从循证医学看我国导航神经外科的发展

神经导航(包括应用术前影像导航和术中影像导航),经过20多年的发展,已成为微侵袭神经外科中的一个重要组成,它改变了现代神经外科已有的诊断手段先进、颅内病灶定位和切除程度判断落后的情况,它使神经外科手术由主观判断上升为客观验证,手术准确性由厘米级提高到毫米级,从而大大提高了手术的安全性和疗效.本期<中华外科杂志>"导航神经外科"重点专栏,刊登的有关文章均证明此点,反映了我国导航神经外科目前发展的水平和可喜状况.