Next generation sequencing in adult patients with glioblastoma in Switzerland: a multi-centre decision analysis.

BACKGROUND: Glioblastoma is the most common malignant primary brain tumour in adults and driven by various genomic alterations. Next generation sequencing (NGS) provides timely information about the genetic landscape of tumours and might detect targetable mutations. To date, differences exist in the application and NGS assays used as it remains unclear to what extent these variants may affect clinical decision making. In this survey-based study, we investigated the use of NGS in adult patients with glioblastoma in Switzerland. METHODS: All eight primary care centres for Neuro-Oncology in Switzerland participated in this survey. The NGS assays used as well as the criteria for the application of NGS in newly diagnosed glioblastoma were investigated. Decision trees were analysed for consensus and discrepancies using the objective consensus methodology. RESULTS: Seven out of eight centres perform NGS in patients with newly diagnosed glioblastoma using custom made or commercially available assays. The criteria most relevant to decision making were age, suitability of standard treatment and fitness. NGS is most often used in fitter patients under the age of 60 years who are not suitable for standard therapy, while it is rarely performed in patients in poor general health. CONCLUSION: NGS is frequently applied in glioblastomas in adults in Neuro-Oncology centres in Switzerland despite seldom changing the course of treatment to date.

Access to the crista galli and the foramen caecum in nasal dermal sinus cysts - lessons learned in a single tertiary care centre.

OBJECTIVE: Several surgical techniques have been suggested for the treatment of nasal dermal sinus cysts (NDSC). We have used several different techniques and have developed a minimally invasive approach. The aim of this study is to describe the evolution to this approach and compare the results with those achieved with our experience of more traditional techniques. METHODOLOGY/PRINCIPAL: A retrospective data collection of patients with NDSC presenting to our clinic between 1998 and 2012 was performed. We initially performed external approaches as outlined elsewhere. With an increasing number of young children requiring surgery, the technique was modified to a less invasive form. This new approach starts with mobilisation of the pit via a tiny skin incision. An open rhinoplasty approach is used to follow the fistula on the nasal bone. Once the fistula passes underneath the nasal bone, an endoscopic endonasal approach is used. Following the fistula cranially, the area of the foramen caecum can be identified. RESULTS: Twelve out of 15 patients (80%) were treated surgically. The transfacial, coronal subcranial and minimally invasive approach was used in 3 (25%), 4 (33%) and 5 patients (42%), respectively. Radical resection was achieved in all patients. Cosmetic problems were present in all patients undergoing a transfacial and in half of the patients after the coronal subcranial approach. Patients treated by the minimally invasive technique remained without sequelae. CONCLUSION: The minimally invasive approach enables a perfect exposure of the fistula up to the crista galli and provides less morbidity and better cosmetic results than the transfacial and subcranial approach.

Intraoperative high frequency ultrasound in intracerebral high-grade tumors.

PURPOSE: To demonstrate the utility of a new concept of intraoperative use of high frequency ultrasound (hfioUS) in maximizing the extent of resection (EOR) of intracerebral high-grade tumors. MATERIALS AND METHODS: 22 Patients harboring an intracerebral high-grade tumor were retrospectively included in this study (14 primary tumors, 8 metastasis). 14 of them had a perilesional edema equal or greater to lesion volume, 3 had previously received radiotherapy. Following macroscopic tumor debulking, the small (11 × 31 mm) L15 - 7io (Philips, Bothell, USA) high-frequency probe (7 - 15 MHz) was introduced into the resection cavity and its walls were meticulously scanned to search for tumor remnants. Postoperative MR scan was evaluated by a board-certified independent neuroradiologist, who assessed the EOR. RESULTS: Gross total resection was achieved in 21 patients (95.5 %). One patient had a small tumor remnant (6 × 4 × 3 mm) of a very large (80 × 60 × 74 mm) anaplastic astrocytoma, detected in the postoperative MR scan. A permanent postoperative hemiparesis was diagnosed in one patient with a metastasis in the motor area, while the other patients recovered without permanent neurological deficits from the surgery. CONCLUSION: The hfioUS probe allowed in this study a precise detection of the tumor and a detailed discrimination between normal, pathological and edematous tissue in all 22 cases.

Comparison of different reconstruction algorithms for three-dimensional ultrasound imaging in a neurosurgical setting.

BACKGROUND: Freehand three-dimensional ultrasound imaging (3D-US) is increasingly used in image-guided surgery. During image acquisition, a set of B-scans is acquired that is distributed in a non-parallel manner over the area of interest. Reconstructing these images into a regular array allows 3D visualization. However, the reconstruction process may introduce artefacts and may therefore reduce image quality. The aim of the study is to compare different algorithms with respect to image quality and diagnostic value for image guidance in neurosurgery. METHODS: 3D-US data sets were acquired during surgery of various intracerebral lesions using an integrated ultrasound-navigation device. They were stored for post-hoc evaluation. Five different reconstruction algorithms, a standard multiplanar reconstruction with interpolation (MPR), a pixel nearest neighbour method (PNN), a voxel nearest neighbour method (VNN) and two voxel based distance-weighted algorithms (VNN2 and DW) were tested with respect to image quality and artefact formation. The capability of the algorithm to fill gaps within the sample volume was investigated and a clinical evaluation with respect to the diagnostic value of the reconstructed images was performed. RESULTS: MPR was significantly worse than the other algorithms in filling gaps. In an image subtraction test, VNN2 and DW reliably reconstructed images even if large amounts of data were missing. However, the quality of the reconstruction improved, if data acquisition was performed in a structured manner. When evaluating the diagnostic value of reconstructed axial, sagittal and coronal views, VNN2 and DW were judged to be significantly better than MPR and VNN. CONCLUSION: VNN2 and DW could be identified as robust algorithms that generate reconstructed US images with a high diagnostic value. These algorithms improve the utility and reliability of 3D-US imaging during intraoperative navigation.

[Intraoperative neurophysiological monitoring improves outcome in neurosurgery]. / Intraoperatives neurophysiologisches Monitoring verbessert das Outcome in der Neurochirurgie.

Intraoperative Neurophysiological Mo-nitoring (IONM) identifies eloquent areas or nerves fibers during neurosurgical interventions and monitors their function. For several interventions IONM has become mandatory in neurosurgery. IONM increases patient safety during surgery as the risk of neurological deficits is reduced. Safer surgery reduces the time needed for the intervention and thereby reduces risk. IONM contributes to complete resection of tumors, which in turn prolongs patients' survival. Complicated surgical interventions associated with an elevated risk of neurological deficits have only become possible due to IONM. IONM comprises a variety of procedures that are selected for a particular intervention. With appropriate selection of the procedures IONM has been shown to improve neurological and functional outcome after neurosurgical interventions.

Intraoperative angiography for hunterian ligation of a recurrent basilar aneurysm.

Cerebral aneurysms often recur after selective endovascular treatment with detachable coils and are usually treated by recoiling. Sometimes, however, surgical treatment is required, and application of the clip can be difficult. Evacuation of embolic material risks injuring eloquent structures or perforators, especially in the posterior circulation. In such cases parent vessel occlusion for reversal of flow might be an option. If collateral flow is adequate, an additional bypass is not required. When using this technique, known as Hunterian ligation, intraoperative monitoring such as electrophysiological monitoring and intraoperative angiography can be of great help and are advisable. We describe this procedure and related intraoperative considerations in one case report.

Image-guided ultrasonography for recurrent cystic gliomas.

BACKGROUND: Long-term survival of patients with recurrent gliomas depends on the extent of resection. Thus, the desirability of an intra-operative imaging modality that can augment the resection extension without affecting vital surrounding structures is more than obvious. It was the aim of the present study to evaluate a possible benefit of image-guided intra-operative ultrasonography for the surgery of recurrent gliomas. METHOD: The authors performed ultrasonography-assisted image-guided resection of recurrent gliomas in 16 patients. An ultrasound device (IGSonic) was integrated into the VectorVision2 navigation system (BrainLAB, Heimstetten, Germany). The IGSonic Probe 10V5 was connected to the VectorVision Navigation station via an IGSonic Device Box. Following patient registration, MRI based neuronavigation was used to determine the skin incision and the bone flap. Before opening the dura, the underlying structures were explored by ultrasound combined with the corresponding MR images. The navigated ultrasound displayed the sonographic image of the intracranial anatomy on the navigation screen in a composed overlay fashion. FINDINGS: The integration of intra-operative ultrasound into neuronavigation system offered quick and helpful intra-operative images in all 16 procedures. Due to the specific ultrasonic characteristics of the solid and the cystic parts, our technique created highly useful images in 10 patients with cystic recurrences. In these, user friendly images were obtained that were easy to understand even for neurosurgeons without major experience in intra-operative ultrasound. CONCLUSIONS: Neurosonography is a time- and cost-effective technology offering intra-operative imaging. The improved orientation and visualization of tumour remnants, adjacent ventricles, and the enhanced intra- and peri-tumoural vasculature is one of the main advantages of ultrasonography-assisted image-guided surgery, which is most obvious during surgery for cystic gliomas.

Clinical application of neuro-navigation in a series of single burr-hole procedures.

With recent developments in computer technology and the improvement of neuroimaging, modern optical neuro-navigation systems are increasingly being used in neurosurgery. In this study, we present our experience with 51 operations using a frameless optical navigation system in a variety of single burr-hole procedures. The procedures include neuroendoscopic surgery, frameless stereotactic biopsy, cyst aspiration and catheter placement. Both the VectorVision and the VectorVision(2) neuro-navigation systems (BrainLab AG, Munich, Germany) were used. The reliability and accuracy of the neuro-navigation system, postoperative complications and the clinical usefulness of image-guidance were analyzed. The navigation system worked properly in all 51 neurosurgical cases. Exact planning of the approach and determination of the ideal trajectory were possible in all cases. The mean registration error of the system, given as a computer-calculated value, was 2.1 mm (0.4-3.1 mm). Postoperative clinical evaluations and imaging were performed on every patient in order to confirm the success of the surgical procedure. All patients recovered well and without any postoperative complications. We conclude that image guidance in single burr-hole procedures provides a high degree of accuracy in lesion targeting, permits good anatomical orientation and minimizes brain trauma. The navigation system has proven to be a helpful tool since it increases the safety of single burr-hole procedures.