Transvenous treatment of CS and transverse/sigmoid sinus AVFs can be effective if all transvenous approaches, including combined surgical/endovascular approaches, are considered.

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This review paper gives an overview and summarizes the different methods of cranioplasty for reconstruction of the bony skull. There are various origins of cranial defects including trauma, tumours, congenital deformities or postoperative defects due to the surgical procedure itself. The overall goal of skull reconstruction is, on the one hand, appropriate closure, and on the other hand, the perfect cosmetic result. The cranioplasty should be safe, fast and easy to handle. Cost-effectiveness of the procedure represents a further important point. To solve these complex and multimodal problems, different techniques and also various materials for the reconstruction are available. This report details the usual procedures for skull reconstruction, as well as the advantages and limitations of the different materials and operative strategies.

The accuracy of image-guided neurosurgery generally suffers from brain deformations due to intraoperative changes. These deformations cause significant changes of the anatomical geometry (organ shape and spatial interorgan relations), thus making intraoperative navigation based on preoperative images error prone. In order to improve the navigation accuracy, we developed a biomechanical model of the human head based on the finite element method, which can be employed for the correction of preoperative images to cope with the deformations occurring during surgical interventions. At the current stage of development, the two-dimensional (2-D) implementation of the model comprises two different materials, though the theory holds for the three-dimensional (3-D) case and is capable of dealing with an arbitrary number of different materials. For the correction of a preoperative image, a set of homologous landmarks must be specified which determine correspondences. These correspondences can be easily integrated into the model and are maintained throughout the computation of the deformation of the preoperative image. The necessary material parameter values have been determined through a comprehensive literature study. Our approach has been tested for the case of synthetic images and yields physically plausible deformation results. Additionally, we carried out registration experiments with a preoperative MR image of the human head and a corresponding postoperative image simulating an intraoperative image. We found that our approach yields good prediction results, even in the case when correspondences are given in a relatively small area of the image only.

MRI is the diagnostic procedure of first choice because of its potential to demonstrate the exact localisation, extent and relationship of the arachnoid cyst to the spinal cord. Cord atrophy secondary to compression can be visualised and used for prediction of neurological outcome. Myelography and CT-Myelography (CTM) are still of diagnostic value since they might demonstrate the communication between the subarachnoid space and the cyst, which is important for surgical planning. The aim of surgical treatment is neural decompression and prevention of refilling of the cyst which is best accomplished by complete resection of the cyst and closure of the communication between cyst and subarachnoid space.

The surgical aim in the treatment of symptomatic lumbar spinal stenosis is the relief of the patient's complaints by an adequate neural decompression. Unilateral laminotomy and bilateral spinal canal decompression represents such a safe, effective and minimally invasive surgical method. This technique has been successfully used in the operative treatment of 29 patients with symptomatic mono- or multisegmental lumbar stenosis. There was no surgically induced neurological deterioration. In one patient, an inadvertent dural tear occurred, and due to unchanged symptoms another patient with a multisegmental stenosis had to be re-operated on at an additional level. Postoperatively, 25 of the 27 patients with neurogenic claudication (93%) demonstrated a marked improvement of the walking distance. The follow-up of 25 patients (mean follow-up time was 18 months) demonstrated an excellent result without pain in 7 patients (28%); a good outcome with mild residual pain, but a normal working capacity in 15 patients (60%); and a fair outcome with unchanged postoperative low-back pain but markedly improved working capacity and walking distance in 3 patients (12%). Postoperative morphometric evaluation as well as the clinical improvement of the patient's symptoms clearly demonstrated that bilateral ligamentectomy and recess decompression were adequately and successfully achieved via unilateral approach.

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A fundamental effort in neurosurgery is to reduce surgical trauma. Microneurosurgical technique combined with precise localization of lesions, can minimize the invasiveness of neurosurgical procedures. This report summarizes the utility of frameless neuronavigator systems and examines their value in reducing operative invasiveness. The basic principle of neuronavigation is the virtual linkage between digitized neuroradiological data and real anatomical structures, allowing an excellent three-dimensional orientation by real-time graphic-anatomic interaction. As frameless graphic interactive neuronavigation is developed further, these devices should become an important component of the modern microneurosurgical armamentarium and reduce surgical morbidity.