Surgical treatment of tentorial dural arteriovenous fistulae located around the tentorial incisura

Tentorial dural arteriovenous fistulae (DAVF) are relatively uncommon and are the most dangerous type of DAVF. Because of a high incidence of hemorrhage and subsequent neurological deficits, treatment is mandatory. A consecutive series of nine surgically treated patients with symptomatic tentorial DAVF were analyzed in this study. All lesions were located around the tentorial incisura and were treated microsurgically using a subtemporal approach in eight cases and a supracerebellar approach in one case. The dural bases of the lesions were located adjacent to the tentorial edge in six patients and the tentorial apex in three patients. Complete obliteration was achieved in all treated tentorial DAVF. In one patient, the torcular fistula remained untreated without cortical venous reflux. Postoperative asymptomatic temporal lobe hemorrhage was diagnosed in one patient with a tentorial apex DAVF; however, no new neurological symptoms were present after surgical treatment. The subtemporal approach for unilateral tentorial DAVF is a favorable and direct approach for the highly skilled surgeon. Perimesencephalic venous dilatation or varix is an important finding on MRI to help localize tentorial DAVF in the tentorial edge or ape

Surgical resection of pediatric skull base meningiomas

Purpose: Meningiomas in children are rare, especially those located at the skull base. In this study, we report our experience of meningioma surgery in the pediatric population and compare our findings of skull base (SB) versus non-skull base (NSB) meningiomas. Methods: From our database of 724 surgically treated meningioma patients at the University Hospital, Zurich between 1995 and 2010, 12 patients under 18years of age were identified. Data for those patients was retrospectively collected through chart review. A descriptive comparison between SB and NSB meningiomas was undertaken to determine statistical significance. Results: In all 12 children (seven males, five females; mean age 12.2 ± 4.3years), surgical removal of the meningioma was performed microsurgically with a mean follow-up of 53months (range 12-137months). Of the 12 tumors, six were located in the SB and six in the NSB. Comparing SB to NSB lesions, the mean age was 11 ± 3.8 versus 14 ± 4.6years, male/female gender distribution was 5:1 compared to 1:5, mean tumor size was 7.5 ± 6.2 versus 26 ± 15.8cm2 (p = 0.03), and mean surgery time was 347 versus 214min. While WHO grade was similar for both groups, the Simpson grade revealed more extensive resection for NSB meningiomas. The Glasgow Outcome Scale at last follow-up was favorable for both groups. Conclusions: Meningioma surgery was safe with favorable outcomes. SB meningiomas were significantly smaller in size, were less likely to undergo complete resection, and had a predilection for younger, male patient

Resection of pediatric intracerebral tumors with the aid of intraoperative real-time 3-D ultrasound

Purpose: Intraoperative ultrasound (IOUS) has become a useful tool employed daily in neurosurgical procedures. In pediatric patients, IOUS offers a radiation-free and safe imaging method. This study aimed to evaluate the use of a new real-time 3-D IOUS technique (RT-3-D IOUS) in our pediatric patient cohort. Material and methods: Over 24months, RT-3-D IOUS was performed in 22 pediatric patients (8 girls and 14 boys) with various brain tumors. These lesions were localized by a standard navigation system followed by analyses before, intermittently during, and after neurosurgical resection using the iU22 ultrasound system (Philips, Bothell, USA) connected to the RT-3-D probe (X7-2). Results: In all 22 patients, real-time 3-D ultrasound images of the lesions could be obtained during neurosurgical resection. Based on this imaging method, rapid orientation in the surgical field and the approach for the resection could be planned for all patients. In 18 patients (82%), RT-3-D IOUS revealed a gross total resection with a favorable neurological outcome. Conclusion: RT-3-D IOUS provides the surgeon with advanced orientation at the tumor site via immediate live two-plane imaging. However, navigation systems have yet to be combined with RT-3-D IOUS. This combination would further improve intraoperative localizatio

Intraoperative low-field MR-guided frameless stereotactic biopsy for intracerebral lesions

Background: To present our intraoperative low-field magnetic resonance imaging (ioMRI) technique for stereotactic brain biopsy in various intracerebral lesions. Method: Seventy-eight consecutive patients underwent stereotactic biopsies with the PoleStar N-20/N-30 ioMRI system and data were evaluated retrospectively. Biopsy technique included ioMRI before surgery, followed by insertion of the biopsy cannula in the lesion, and ioMRI before and after biopsy. Statistical analysis was performed to compare subgroups using Excel and SPSS statistic software. Results: In all patients, stereotactic biopsy was possible, with a mean intraoperative surgery time of 86.2 ± 28.6min and a mean hospital stay of 11.6 ± 4.6days. In 97.4% (n = 76), histology was conclusive, representing 58 brain tumors and 18 other pathologies. Five patients were biopsied previously without conclusive diagnosis, and all biopsies were conclusive this time. Mean cross-sectional lesion size in MRI T1 with contrast (n = 64) was 6.9 ± 5.7cm2, and in lesions without T1 contrast enhancement (n = 14), T2 mean cross-sectional lesion size was 5.5 ± 3.9cm2. Mean distance from the cortex surface to the lesion was 3.4 ± 1.2cm. One patient suffered from a postoperative wound dehiscence; neither clinically or radiologically significant hemorrhage after surgery, nor intraoperative complications occurred. Conclusions: Low-field ioMR-guided frameless stereotactic biopsy accurately diagnosed different intracerebral lesions without major complications for the patients, and within an acceptable surgery time and hospital stay. In repeated non-conclusive biopsies in particular, low-field ioMRI offers a technique for arriving at a diagnosi

Neurosurgical education in Europe and the United States of America

Training in neurological surgery is one of the most competitive and demanding specializations in medicine. It therefore demands careful planning in both the scientific and clinical neurosurgery arena to finally turn out physicians that can be clinically sound and scientifically competitive. National and international training and career options are pointed out, based on the available relevant literature, with the objective of comparing the neurosurgical training in Europe and the USA. Despite clear European Association of Neurosurgical Societies guidelines, every country in Europe maintains its own board requirements, which is reflected in an institutional curriculum that is specific to the professional society of that particular country. In contrast, the residency program in the USA is required to comply with the Accreditation Council for Graduate Medical Education guidelines. Rather similar guidelines exist for the education of neurosurgical residents in the USA and Europe; their translation into the practical hospital setting and the resulting clinical lifestyle of a resident diverges enormously. Since neurosurgical education remains heterogeneous worldwide, we argue that a more standardized curriculum across different nations would greatly facilitate the interaction of different centers, allow a direct comparison of available services, and support the exchange of vital information for quality control and future improvements. Furthermore, the exchange of residents between different training centers may improve education by increasing their knowledge base, both technically as well as intellectuall

Intra-operative high frequency ultrasound improves surgery of intramedullary cavernous malformations

Intra-operative ultrasound (ioUS) is a very useful tool in surgery of spinal lesions. Here we focus on modern ioUS to analyze its use for localisation, visualisation and resection control in intramedullary cavernous malformations (IMCM). A series of 35 consecutive intradural lesions were operated in our hospital in a time period of 24months using modern ioUS with a high frequency 7-15MHz transducer and a true real time 3D transducer (both Phillips iU 22 ultrasound system). Six of those cases were treated with the admitting diagnosis of a deep IMCM (two cervical, four thoracic lesions). IoUS images were performed before and after the IMCM resection. Pre-operative and early postoperative MRI images were performed in all patients. In all six IMCM cases a complete removal of the lesion was achieved microsurgically resulting in an improved neurological status of all patients. High frequency ioUS emerged to be a very useful tool during surgery for localization and visualization. Excellent resection control by ultrasound was possible in three cases. Minor resolution of true real time 3D ioUS decreases the actual advantage of simultaneous reconstruction in two planes. High frequency ioUS is the best choice for intra-operative imaging in deep IMCM to localize and to visualize the lesion and to plan the perfect surgical approach. Additionally, high frequency ioUS is suitable for intra-operative resection control of the lesion in selected IMCM case

Bringing high-grade arteriovenous malformations under control: clinical outcomes following multimodality treatment in children.

OBJECTIVE:Brain arteriovenous malformations (AVMs) consist of dysplastic blood vessels with direct arteriovenous shunts that can hemorrhage spontaneously. In children, a higher lifetime hemorrhage risk must be balanced with treatment-related morbidity. The authors describe a collaborative, multimodal strategy resulting in effective and safe treatment of pediatric AVMs. METHODS:A retrospective analysis of a prospectively maintained database was performed in children with treated and nontreated pediatric AVMs at the University of California, San Francisco, from 1998 to 2017. Inclusion criteria were age ≤ 18 years at time of diagnosis and an AVM confirmed by a catheter angiogram. RESULTS:The authors evaluated 189 pediatric patients with AVMs over the study period, including 119 ruptured (63%) and 70 unruptured (37%) AVMs. The mean age at diagnosis was 11.6 ± 4.3 years. With respect to Spetzler-Martin (SM) grade, there were 38 (20.1%) grade I, 40 (21.2%) grade II, 62 (32.8%) grade III, 40 (21.2%) grade IV, and 9 (4.8%) grade V lesions. Six patients were managed conservatively, and 183 patients underwent treatment, including 120 resections, 82 stereotactic radiosurgery (SRS), and 37 endovascular embolizations. Forty-four of 49 (89.8%) high-grade AVMs (SM grade IV or V) were treated. Multiple treatment modalities were used in 29.5% of low-grade and 27.3% of high-grade AVMs. Complete angiographic obliteration was obtained in 73.4% of low-grade lesions (SM grade I-III) and in 45.2% of high-grade lesions. A periprocedural stroke occurred in a single patient (0.5%), and there was 1 treatment-related death. The mean clinical follow-up for the cohort was 4.1 ± 4.6 years, and 96.6% and 84.3% of patients neurologically improved or remained unchanged in the ruptured and unruptured AVM groups following treatment, respectively. There were 16 bleeding events following initiation of AVM treatment (annual rate: 0.02 events per person-year). CONCLUSIONS:Coordinated multidisciplinary evaluation and individualized planning can result in safe and effective treatment of children with AVMs. In particular, it is possible to treat the majority of high-grade AVMs with an acceptable safety profile. Judicious use of multimodality therapy should be limited to appropriately selected patients after thorough team-based discussions to avoid additive morbidity. Future multicenter studies are required to better design predictive models to aid with patient selection for multimodal pediatric care, especially with high-grade AVMs

Brainstem cavernoma surgery with the support of pre- and postoperative diffusion tensor imaging: initial experiences and clinical course of 23 patients

The spatial complexity of highly vulnerable structures makes surgical resection of brainstem cavernomas (BSC) a challenging procedure. Diffusion tensor imaging (DTI) allows for the visualization of white matter tracts and enables a better understanding of the anatomical location of corticospinal and sensory tracts before and after surgery.We investigated the feasibility and clinical usefulness of DTI-based fiber tractography in patients with BSC.Pre- and postoperative DTI visualization of corticospinal and sensory tracts were retrospectively analyzed in 23 individuals with BSC. Preoperative and postoperative DTI-fiber accuracy were associated to the neurological findings. Preoperatively, the corticospinal tracts were visualized in 90% of the cases and the sensory tracts were visualized in 74% of the cases. Postoperatively, the corticospinal tracts were visualized in 97% of the cases and the sensory tracts could be visualized in 80% of the cases. In all cases, the BSC had caused displacement, thinning, or interruption of the fiber tracts to various degrees. Tract visualization was associated with pre- and postoperative neurological findings. Postoperative damage of the corticospinal tracts was observed in two patients. On follow-up, the Patzold Rating (PR) improved in 19 out of 23 patients (83%, p = 0.0002).This study confirms that DTI tractography allows accurate and detailed white matter tract visualization in the brainstem, even when an intraaxial lesion affects this structure. Furthermore, visualizing the tracts adjacent to the lesion adds to our understanding of the distorted intrinsic brainstem anatomy and it may assists in planning the surgical approach in specific cases