Microsurgical treatment of cranial and spinal dural arteriovenous fistulas for acute occlusion: a single institution's experience.

OBJECTIVES: To determine the success rate of primary microsurgical treatment of both cranial and spinal dural arteriovenous fistulas (cdAVFs and sdAVFs). METHODS: Data of 40 consecutive patients (mean age, 64.5 years; range, 35-88 years) who underwent microsurgical treatment for a diagnosed cdAVF/sdAVF at a single academic institution were retrospectively obtained. General patient information, such as age on the day of surgery and sex, patient charts, admission protocols, operating reports, and discharge protocols were reviewed. Outcomes, including modified Rankin Scale (mRS) scores and the rate of complete occlusion confirmed by a postoperative angiography were analyzed. RESULTS: The overall post-treatment occlusion rate was 100% in sdAVFs and 92% in cdAVFs. The most common presentation of cdAVFs was intracerebral hemorrhage (67%), followed by headache (53%) and vertigo (33%). The main symptoms of sdAVFs were sensory deficits, paresis, gait abnormalities, and incontinence. Additional endovascular treatment after primary surgery was needed in seven (47%) patients with cdAVF and one patient (4%) with sdAVF. All sdAVFs were classified as Cognard grade V, while six (40%) cdAVFs were Cognard grade III, eight (54%) were grade IV and one (6%) was grade V. Complications included cerebrospinal fluid (CSF) fistulas, CSF circulation disorders, meningitis, and epidural and intracerebral hemorrhages. Furthermore, sdAVF showed higher rates of clinical improvement than cdAVF (56% vs. 47%). DISCUSSION: Microsurgery resulted in complete occlusion in most cases of sdAVFs. However, additional endovascular treatment was necessary in nearly 50% of patients with cdAVF. Therefore, combined treatment in cranial cdAVF seems to be the desired strategy.

FRED Flow Diverter: A Study on Safety and Efficacy in a Consecutive Group of 50 Patients.

BACKGROUND AND PURPOSE: Endovascular flow diverters are increasingly used for the treatment of cerebral aneurysms. We assessed the safety and efficacy of the Flow-Redirection Endoluminal Device (FRED) in a consecutive series of 50 patients. MATERIALS AND METHODS: Inclusion criteria were wide-neck, blister-like, or fusiform/dissecting aneurysms independent of size, treated with the FRED between February 2014 and May 2015. Assessment criteria were aneurysm occlusion, manifest ischemic stroke, bleeding, or death. The occlusion rate was assessed at 3 months with flat panel CT and at 6 months with DSA by using the Raymond classification and the O'Kelly-Marotta grading scale. RESULTS: Fifty patients with 52 aneurysms were treated with 54 FREDs; 20 patients were treated with the FRED and coils. Aneurysm size ranged from 2.0 to 18.5 mm. Deployment of the FRED was successful in all cases. There were no device-associated complications. One patient developed mild stroke symptoms that fully receded within days. There have been no late-term complications so far and no treatment-related mortality. Initial follow-up at 3 months showed complete occlusion in 72.3% of the overall study group, Six-month follow-up showed total and remnant-neck occlusion in 87.2% of patients, distributed over 81.5% of the FRED-only cases and 95.0% of the cases with combined treatment. CONCLUSIONS: The FRED flow diverter is a safe device for the treatment of cerebral aneurysms of various types. Our data reveal high occlusion rates at 3 and 6 months, comparable with those in other flow diverters. Long-term occlusion rates are expected.

Motives for sports participation as predictions of self-reported outcomes after anterior cruciate ligament injury of the knee.

Aim of the study was to access how individual's motives for participation in sports impact on self-reported outcomes 2 years after an anterior cruciate ligament injury. Based on a longitudinal cohort study, this secondary analysis present data from the Knee Anterior Cruciate Ligament, Nonsurgical versus Surgical Treatment (KANON) study, a randomized controlled trial. At baseline, 121 patients recorded in an initial questionnaire that their motives for sports participation fell into four categories: achievement, health, social integration, or fun and well-being. These four categories were used as variables in the analyses. All 121 subjects completed the 2-year follow-up. The largest improvement was seen in the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale sports and recreation function, with an effect size of 2.43. KOOS sports and recreation function was also the subscale score best predicted by the motives for sports participation. Baseline motives achievement and fun and well-being predicted worse levels of pain and function 2 years after the injury, even after adjusting for age, gender, treatment and baseline scores. Psychological aspects, such as motives for participation in sport, can be factors in predicting of patient-reported outcomes 2 years after injury. Evaluating motives for sports participation may help predict the outcome 2 years after ACL injury.

Optimized angiographic CT using intravenous contrast injection: a noninvasive imaging option for the follow-up of coiled aneurysms?

BACKGROUND AND PURPOSE: Because recanalization of coiled cerebral aneurysms is reported to occur, follow-up imaging is mandatory, ideally noninvasively. Our study aimed to evaluate the accuracy of an optimized angiographic CT by using intravenous contrast material injection in the assessment of coiled cerebral aneurysms, compared with MR angiography and digital subtraction angiography, the criterion standard. MATERIALS AND METHODS: We included 69 patients with 76 coiled cerebral aneurysms. In each patient, we performed an angiographic CT with intravenous contrast material injection with a dual rotational acquisition, a time-of-flight MR angiography, and a DSA. The angiographic CT with intravenous contrast material injection data was postprocessed by using newly implemented reconstructions modes and a dual-volume technique. An aneurysm occlusion rate was assessed in angiographic CT with intravenous contrast material injection and MRA; remnants were measured and correlated with DSA, respectively. RESULTS: Twenty-eight remnants were revealed by DSA with a mean size of 3.1 × 3.1 mm. Angiographic CT with intravenous contrast material injection demonstrated a sensitivity of 93% and a specificity of 96% in remnant detection. MRA showed almost identical accuracy (sensitivity of 93%, specificity of 100%). Assessment of remnant size by angiographic CT with intravenous contrast material injection and by MRA revealed a high significant correlation with DSA, respectively (P < .001). CONCLUSIONS: Optimized angiographic CT with intravenous contrast material injection and MRA demonstrated accuracy comparable with that of DSA in the follow-up of coiled aneurysms, respectively. The assessment of remnant size showed a high correlation with DSA for both techniques. Due to the lack of radiation exposure, MRA seems to be the preferred technique. However, angiographic CT with intravenous contrast material injection can be considered a reliable, noninvasive alternative in patients with MR imaging contraindications or in cases of compromising artifacts due to metal implants (ie, clips).

Does work-site physical activity improve self-reported psychosocial workplace factors and job satisfaction? A randomized controlled intervention study.

PURPOSE: To investigate whether a work-site strength-training program has a positive effect on self-reported psychosocial workplace factors and job satisfaction. METHODS: We conducted a randomized controlled trial among laboratory technicians implementing neck and shoulder exercises for pain relief, with 199 participants in the training group and 228 in the control group. Influence at work, sense of community, time pressure, and job satisfaction were measured with the Copenhagen Psychosocial Questionnaire at baseline and post-intervention after 20 weeks. RESULTS: There was no statistically significant change in any of the four variables in the training group from baseline to follow-up (all p ≥ 0.39). When we used MANOVA to test for between-group effects over time, we did not find any statistically significant result (all p > 0.14). CONCLUSIONS: This study does not provide evidence for an effect of a work-site strength-training program on self-reported psychosocial workplace factors and job satisfaction.

Successful talent development in track and field: considering the role of environment.

Track and field includes a number of high-intensity disciplines with many demanding practices and represents a motivational challenge for talented athletes aiming to make a successful transition to the senior elite level. Based on a holistic ecological approach, this study presents an analysis of a particular athletic talent development environment, the IFK Växjö track and field club, and examines key factors behind its successful history of creating top-level athletes. The research takes the form of a case study. Data were collected from multiple perspectives (in-depth interviews with administrators, coaches and athletes), from multiple situations (observation of training, competitions and meetings) and from the analysis of documents. The environment was characterized by a high degree of cohesion, by the organization of athletes and coaches into groups and teams, and by the important role given to elite athletes. A strong organizational culture, characterized by values of open co-operation, by a focus on performance process and by a whole-person approach, provided an important basis for the environment's success. The holistic ecological approach encourages practitioners to broaden their focus beyond the individual in their efforts to help talented junior athletes make a successful transition to the elite senior level.

Surgical target selection in cerebral glioma surgery: linking methionine (MET) PET image fusion and neuronavigation.

OBJECTIVE: The objective of this study was to investigate the histological correlate of (11)C-methionine (MET) PET uptake of brain gliomas by image fusion for navigated surgery. METHODS: Twenty-seven patients (18 male, 9 female; mean age 42 years; range 11-77 years; 8 low-grade and 11 high-grade astrocytomas or mixed gliomas, 8 oligodendrogliomas) underwent MET PET studies preoperatively. RESULTS: MET PET tumor uptake was detected in 26 of 27 patients (96.3%). The quantitative MET tumor standardized uptake value (SUV) ratio was significantly higher in malignant gliomas and oligodendrogliomas than in low-grade gliomas (2.76/2.62 vs. 1.67, p=0.03). Generally, qualitative visual grading of MET uptake revealed 2 main patterns: focal MET uptake in 12 and uniform global MET uptake in 11 patients. Focal uptake corresponded to malignant glioma histology in 66.7%, and uniform global uptake to oligodendroglial histology in 72.7%. In oligodendrogliomas, global MET uptake constituted 81.5% (range 53.8-135%) of the MRI T(1) tumor volume on average and was limited to the MRI FLAIR tumor volume in 86% (7/8) of patients. Tissue samples of focal MET uptake areas correlated with histological anaplasia in 66.6% (8/12 glioma patients), although 62.5% (5/8 patients) lacked MRI contrast enhancement. CONCLUSION: MET PET image fusion may facilitate the targeting of anaplastic foci in homogeneous MRI non-enhancing gliomas for biopsy, may identify oligodendroglial histology preoperatively as well as characterize biologically active tumor volumes within MRI T(1)/FLAIR tumor areas of candidate patients for resection.

Evaluation of preoperative high magnetic field motor functional MRI (3 Tesla) in glioma patients by navigated electrocortical stimulation and postoperative outcome.

OBJECTIVES: The validity of 3 Tesla motor functional magnetic resonance imaging (fMRI) in patients with gliomas involving the primary motor cortex was investigated by intraoperative navigated motor cortex stimulation (MCS). METHODS: Twenty two patients (10 males, 12 females, mean age 39 years, range 10-65 years) underwent preoperative fMRI studies, performing motor tasks including hand, foot, and mouth movements. A recently developed high field clinical fMRI technique was used to generate pre-surgical maps of functional high risk areas defining a motor focus. Motor foci were tested for validity by intraoperative motor cortex stimulation (MCS) employing image fusion and neuronavigation. Clinical outcome was assessed using the Modified Rankin Scale. RESULTS: FMRI motor foci were successfully detected in all patients preoperatively. In 17 of 22 patients (77.3%), a successful stimulation of the primary motor cortex was possible. All 17 correlated patients showed 100% agreement on MCS and fMRI motor focus within 10 mm. Technical problems during stimulation occurred in three patients (13.6%), no motor response was elicited in two (9.1%), and MCS induced seizures occurred in three (13.6%). Combined fMRI and MCS mapping results allowed large resections in 20 patients (91%) (gross total in nine (41%), subtotal in 11 (50%)) and biopsy in two patients (9%). Pathology revealed seven low grade and 15 high grade gliomas. Mild to moderate transient neurological deterioration occurred in six patients, and a severe hemiparesis in one. All patients recovered within 3 months (31.8% transient, 0% permanent morbidity). CONCLUSIONS: The validation of clinically optimised high magnetic field motor fMRI confirms high reliability as a preoperative and intraoperative adjunct in glioma patients selected for surgery within or adjacent to the motor cortex.

Epidural metastasis of a glioblastoma after stereotactic biopsy: case report.

Tumor seeding along the biopsy tract is a rare complication in stereotactic biopsy. We present the unique case of a 42-year-old male with epidural tumor seeding along the needle tract after computer tomography-guided stereotactic biopsy of a glioblastoma in the right basal ganglia. Three months after the biopsy and one week following fractionated radiation therapy, the patient died of brain edema and cardiac dilatation. Besides further tumor growth at the primary site, autopsy revealed a right frontal epidural, nodular metastatic tumor at the site of dura incision of the stereotactic biopsy. Histological examination showed a glioblastoma that spread epidurally along the needle tract. This is the first report of an epidural intracranial implantation metastasis of a glioblastoma after stereotactic biopsy.

Gamma knife radiosurgery of recurrent central neurocytomas: a preliminary report.

OBJECTIVES: A series of three recurrent central neurocytomas treated by gamma knife radiosurgery (GKRS), which were initially totally resected, are described. Up to now, no reports exist on this treatment modality for this rare tumour entity. METHODS: Three male patients, aged between 20 and 25 years, presented with large intraventricular tumours. Total tumour removal was achieved by a single surgical procedure (one patient) or two operations (two patients). Neuropathological investigation showed a central neurocytoma, immunohistochemically all three tumours expressed a neuronal antigenic profile typical for neurocytomas, and the MIB-1 proliferation index ranged from 2.4% to 8.7%. Each patient experienced a tumour recurrence after 5 to 6 years. The recurrence was multifocal in two and a singular tumour mass in one patient. Gamma knife radiosurgery was performed. The tumours were enclosed within the 30% to 60% isodoseline, and delivered a tumour marginal dose of 9.6 to 16 Gy. During the follow up period, the patients were tested clinically and the volume of the tumours was measured on MRI. RESULTS: Within follow up periods of 1 to 5 years, control MRI showed a significant decrease of the tumour mass in all cases. None of the patients developed new neurological symptoms after GKRS. Two patients returned to work in their previous employment, whereas one patient remained permanently disabled due to a pre-existing visual impairment and abducens palsy. CONCLUSION: GKRS proved to be a useful tool in the treatment of recurrent central neurocytomas. Tumour control and even tumour shrinkage can be achieved with a single procedure and a low risk of morbidity.

Gamma knife radiosurgery of skull base meningiomas.

BACKGROUND: The standard surgical treatment of meningiomas is total resection of the tumour. The complete removal of skull base meningiomas can be difficult because of the proximity of cranial nerves. Stereotactic radiosurgery (SRS) is an effective therapy, either for adjuvant treatment in case of subtotal or partial tumour resection, or as solitary treatment in asymptomatic meningiomas. METHOD: Between September 1992 and October 1995. SRS using the Leksell Gamma Knife was performed on 46 patients (f:m 35:15), ranging in age from 35 to 81 years, with skull base meningiomas at the Neurosurgical Department of the University of Vienna. According to the indication of gamma knife radiosurgery (GKRS) the patients (n = 46) were divided into two subgroups. Group I (combined procedure: subtotal resection followed by GKRS as a planned procedure or because of a recurrent meningioma), group II (GKRS as the primary treatment). Histological examination of tumour tissue was available for 31 patients (67%) after surgery covering 25 benign (81%) and 6 malignant (19%) meningioma subtypes. FINDINGS: The overall tumour control rate after a mean follow-up period of 48 months (ranging from 36 to 76 months) was 96% (97.5% in benign and 83% in malignant meningiomas). Group I displayed a 96.7% tumour control rate, followed by group II with 93.3% respectively. Neurological follow-up showed an improvement in 33% stable clinical course in 58%) and a persistent deterioration of clinical symptoms in 9%. Remarkable neurological improvement after GKRS was observed in group II (47%), whereas in group I (26%) the amelioration of symptoms was less pronounced. INTERPRETATION: GKRS in meningiomas is a safe and effective treatment. A good tumour control and low morbidity rate was achieved in both groups (I, II) of our series, either as a primary or adjunctive therapeutic approach. The planned combination of microsurgery and GKRS extends the therapeutic spectrum in the treatment of meningiomas. Reduction of tumour volume, increasing the distance to the optical pathways and the knowledge of the actual growing tendency by histological evaluation of the tumour minimises the risk of morbidity and local regrowth. Small and sharply demarcated tumours are in general ideal candidates for single high dose-GKRS, even after failed surgery and radiation therapy, and in special cases also in larger tumour sizes with an adapted/reduced margin dose.

Evaluation of big endothelin-1 concentrations in serum and ventricular cerebrospinal fluid after early surgical compared with nonsurgical management of ruptured intracranial aneurysms.

OBJECT: Whereas the removal of subarachnoid blood is possible during early-stage aneurysm surgery, this cannot be achieved in aneurysms treated by endovascular means. The levels of potential spasmogens in the cerebrospinal fluid (CSF) in patients receiving endovascular treatment might therefore be higher, with the potential for more severe post-subarachnoid hemorrhage (SAH) vasospasm. METHODS: Serum and CSF concentrations of big endothelin (ET)-1 were serially measured in patients with SAH receiving one of the following treatments: 1) early (within 72 hours of SAH) aneurysm surgical treatment (15 patients), 2) early endovascular treatment (17 patients), or 3) no intervention in the acute phase (12 patients). In patients suffering delayed infarctions higher levels of big ET-1 CSF were demonstrated than in those without infarctions (p = 0.01). In patients in whom surgery was performed in the acute phase lower big ET-1 CSF concentrations were demonstrated than in those who received embolization treatment or no treatment (p = 0.02). Subgroup analysis demonstrated that in patients receiving early endovascular treatment, higher big ET-1 CSF concentrations were revealed than in those undergoing early aneurysm surgery; this was true for patients with (microsurgerytreated, 1.84 +/- 0.83 pg/ml; and embolization-treated 2.19 +/- 0.54 pg/ml) and without (microsurgery-treated 1.76 +/- 0.61 pg/ml; and embolization-treated 2.01 +/- 0.48 pg/ml) delayed infarctions. CONCLUSIONS: Among patients with SAH who received treatment during the acute phase, those undergoing early aneurysm surgery were shown to have lower big ET-1 CSF levels than those receiving embolization and no treatment (that is, the nonsurgical treatment groups). The clinical significance of this finding remains to be established in future clinical trials, because in the present study the trend toward lower levels of big ET-1 CSF in the microsurgically treated group was not paralleled by a lower delayed stroke rate or an improvement in neurological outcome.

Multiple spinal "miliary" hemangioblastomas in von Hippel-Lindau (vHL) disease without cerebellar involvement. A case report and review of the literature.

We report on a 57-year-old male presenting with radicular pain in the nerve roots of L5 and S1 on the right side and dysuria. Magnetic resonance imaging (MRI) of the lumbar spine showed multiple (up to 20) small, intradural enhancing nodules attached to the cauda equina down to the sacrum, the largest 1 cm in diameter at the level Th12/L1 compressing the conus. Additionally, small nodules in the cervico-thoracal region adjacent to the cord, but no cerebellar or cerebral abnormalities, were detected in a consecutive MRI of the remaining neuroaxis. The histology of a resected lesion at Th12/L1 revealed hemangioblastoma of the reticular type. Together with a history of left eye enucleation performed 17 years ago for angiomatosis of the retina and the immunohistochemical detection of von Hippel-Lindau (vHL) protein within the removed spinal hemangioblastoma, a diagnosis of vHL disease was established. Family history and screening for visceral manifestations of vHL disease were negative. In contrast to cerebellar or solitary spinal hemangioblastomas, multiple spinal hemangioblastomas without cerebellar involvement in vHL represent unusual manifestations. Unlike the case for solitary lesions in non-syndromic patients, a surgical cure does not seem feasible in this case. The role of treatment modalities is discussed.

Expression of BCL-2 oncoprotein on tumor cells and tumor-infiltrating lymphocytes (TIL) in meningiomas.

The Expression of the antiapoptotic oncoprotein BCL-2 and its correlation to tumor grade in 62 meningiomas (48 classic, 9 atypical, and 5 anaplastic) using single and double immunohistochemistry was investigated. BCL-2 expression was found in two different cell populations identified as lymphocytes (BCL-2+CD3+) and tumor cells (BCL+/CD3-). Tumor-infiltrating lymphocytes (TIL) (CD3+) were found within classic (9.5% of cells), atypical (2.4% of cells), and anaplastic (1.8% of cells) meningiomas. In classic meningiomas, 66.5% of TIL were BCL-2-positive, in atypical meningiomas 79.2%, and in anaplastic meningiomas 37.9%. In 33 (68.8%) of the classic meningiomas, medium to high counts of BCL-2+ tumor cells were detected. Atypical meningiomas showed nearly equal percentages of high (two patients), medium (five patients), and low (two patients) BCL-2+ tumor cell counts, whereas anaplastic meningiomas showed only medium (two patients) and low (three patients) BCL-2 tumor cell counts or were BCL-2-negative (one patient). In summary, a significant inverse correlation between the number of BCL-2-positive tumor cells and tumor grade in meningiomas was found. These findings support the hypothesis of cell survival prolongation by the antiapoptotic ability of BCL-2 proto-oncogenes and demonstrate the prognostic relevance of BCL-2 immunoreactivity in meningiomas.

Image-guided neurosurgery comparing a pointer device system with a navigating microscope: a retrospective analysis of 208 cases.

A retrospective analysis of neuronavigation procedures performed at the Vienna Neurosurgical Clinic was undertaken to elucidate the advantages of 2 technically different navigation systems in clinical use. In a 30-month period, 208 frameless stereotactic procedures were performed using a stereotactic microscope (MKM System, Zeiss; 92 procedures in 87 patients; 47 female, 40 male; mean age, 46 yrs) and a light emitting diode (LED) based pointer navigation device (Easy Guide Neuro (EGN), Philips; 116 procedures in 114 patients; 63 female, 51 male; mean age 46.4 yrs). The navigating microscope was exclusively used for cranial navigation, the pointer device system in 107 cases for cranial and in 9 cases for spinal navigation. Procedures were CCT-guided in 109 cases, MRI-guided in 95, and both CT/MRI guided in 4 cases. Skin fiducials were used in all these procedures. The MKM system provided coordinate-based navigation, similar to frame systems. This allowed surgical planning and performance using stereotactic coordinates for target calculation. Additionally, tumor volumes were defined by contours and projected into the ocular of the microscope, allowing guidance during targeting and resection of lesions. Both of these features proved beneficial in tumor surgery (60.8% MKM cases), cavernoma surgery (21.8% MKM cases), and epilepsy surgery (14.1% MKM cases). In contrast to the microscope, the pointer navigation system could be employed for intuitive correlation of image points with points of interest in the operating field by using a LED-equipped pointer device. This permitted image guidance during a wide spectrum of neurosurgical procedures, in tumor surgery (68.1% EGN cases), cavernoma surgery (5.1% EGN cases), epilepsy surgery (14.1% EGN cases), vascular surgery (3.4% EGN cases), spinal surgery (7.8% EGN cases), and guidance for burr holes and drainages (6.9% EGN cases), without calculating stereotactic coordinates. This analysis showed clear differences in the application of the two systems and may facilitate the decision as to which system best meets the individual demands of a neurosurgical department.

Frameless stereotactic lesion contour-guided surgery using a computer-navigated microscope.

BACKGROUND: The Zeiss MKM System is a recently developed computerized operating microscope for image-guided neurosurgery. The clinical advantages, reliability, accuracy, and limitations of this technique were investigated. METHODS: Since February 1995, 78 consecutive frameless stereotactic image-guided procedures were performed in 73 patients (30 males, 43 females; mean age, 46.9 years; range, 16-77 years) for tumor surgery (50/64.1%), cavernoma removal (16/20.5%), and functional procedures (12/15.4%). Skin markers (74 cases) or bone markers (4 cases) and a standard imaging protocol (2-mm cranial computed tomography (CCT) in 59 cases/1.5-mm magnetic resonance imaging (MRI) in 19 cases) were used. RESULTS: The main advantages were pre-operative skin incision, craniotomy and corticotomy planning, and determination of lesion boundaries. Useful registration and system reliability were noted in 97% (76/78) of the procedures. A significant improvement in registration accuracy was observed over the test period from a mean of 4.8 mm (SD = 3.36; Cases 1-25) to a mean of 2.2 mm (SD = 0.86; Cases 26-78). This resulted in an improvement in application accuracy from <5 mm in 71% (Cases 1-25) to <2 mm in 95% (Cases 26-78) of cases, and the accuracy led to successful localization of the lesion in every case. Accuracy was reliable at the beginning of every procedure, but degraded to values >5 mm by the end of the procedure in 29% (22/78) of cases. MRI cases achieved higher application accuracy values (2.1 mm mean) than CT cases (3.7 mm mean). CONCLUSIONS: The system offers a reliable alternative to frame-assisted stereotactic craniotomies in lesion targeting, but would need an intraoperative image update for resection guidance.

Frameless stereotactic-directed tissue sampling during surgery of suspected low-grade gliomas to avoid histological undergrading.

Detection of anaplastic tumor foci for precise grading of gliomas is crucial for prognostic assessment and appropriate postoperative treatment planning. To avoided undergrading in large suspected low-grade gliomas, we employed frameless sterotaxy during open surgery for tissue sampling of radiologically suspected anaplastic foci. In nine patients (mean age 44 years, range 10-67) with large supratentorial suspected low-grade gliomas (32.4 ccm mean vol, range 17.9-68.6 ccm) with small contrast enhancing areas (7.7% mean of total volume, range 0.7-15.3%), a neuronavigation system with a pointer device (Easy Guide System Philips) or a navigating microscope (MKM System Zeiss) was used to target small enhancing tumor parts for cytological investigation during open surgery. Consecutive cytological smears revealed anaplastic tumor foci in all patients, correlating with neuroradiologically demonstrated small contrast enhancing areas, although biopsies from all other tumor parts showed low-grade tumors. Final neuropathological diagnosis confirmed anaplasia within the neuroradiologically suspected low-grade gliomas in all patients (2 grade IV, 5 WHO grade III and 2 grade II-III tumors, WHO classification). In our experience frameless stereotactic-directed intraoperative tissue sampling during open surgery of large suspected low-grade gliomas helps to identify small anaplastic areas in mostly large low-grade tumors, and therefore, permits optimum planning of postoperative treatment.

Xanthogranuloma of the anterior skull base: a case report.

A case of a xanthogranuloma arising in the anterior skull base involving the bone of the left orbital roof, the dura mater, and the periorbit is presented. The lesion was completely removed by a supraorbital "eyebrow" skin incision using frameless stereotactic image guidance. A reconstruction of the orbital roof was performed using a titanium mesh graft. The neuropathological investigation revealed all the characteristics of a xanthogranuloma. Intracranially, xanthogranulomas appear as rare tumors of the dura or choroid plexus, usually arising in association with histocytosis X or familial hyperlipoproteinemia. One case not associated with these diseases is discussed.

Frameless stereotactic guided neurosurgery: clinical experience with an infrared based pointer device navigation system.

An infrared based frameless stereotactic navigation device (Easy Guide Neuro) was investigated for its clinical applicability, registration/application accuracy and limitations in a standard operating room set-up. In a five-month period 40 frameless stereotactic procedures (23 female, 17 male, mean age 46.4, yrs range 10-83) including 36 craniotomies and 4 spinal surgery procedures were performed. Image registration, data transfer and operation planning using skin fixed fiducials (between 5-10, mean 6.6) and CCT in 12 patients/MRI in 28 patients, generally was done the day before surgery. Clinical applicability was proven in all procedures with an additional time for pre-operative imaging and system application in the OR of 50 min mean (35-120 range). A useful registration was achieved in 39/40 patients (97.5%) with a registration accuracy of 3.4 mm (range 1.8-6.7) for brain surgery cases and 14.4 mm (6.8-25) for spine cases. This resulted in intra-operative application accuracy values for brain surgery of 4.2 mm mean (range 1-12). Enhanced registration/application accuracy values over the test period from 4.2/3.8 mm mean (Cases 1-20) up to 3.2/2 mm mean (Cases 21-40) was observed. In spinal surgery an application accuracy of 11.3 mm mean (range 5-20) was found. An intra-operative re-calibration because of system-head drift was necessary in none of the patients, nevertheless, application accuracy degradation due to brain shift was detected in every case. In conclusion, the system allowed a time sufficient accurate frameless intra-operative localisation guidance in cavernoma, meningioma, glioma, and brain metastasis surgery. In spinal surgery, the application accuracy exceeded clinical usefulness due to high registration inaccuracy using skin markers.