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In this contribution, a medical software system for volumetric analysis of different cerebral pathologies in magnetic resonance imaging (MRI) data is presented. The software system is based on a semi-automatic segmentation algorithm and helps to overcome the time-consuming process of volume determination during monitoring of a patient. After imaging, the parameter settings-including a seed point-are set up in the system and an automatic segmentation is performed by a novel graph-based approach. Manually reviewing the result leads to reseeding, adding seed points or an automatic surface mesh generation. The mesh is saved for monitoring the patient and for comparisons with follow-up scans. Based on the mesh, the system performs a voxelization and volume calculation, which leads to diagnosis and therefore further treatment decisions. The overall system has been tested with different cerebral pathologies-glioblastoma multiforme, pituitary adenomas and cerebral aneurysms- and evaluated against manual expert segmentations using the Dice Similarity Coefficient (DSC). Additionally, intra-physician segmentations have been performed to provide a quality measure for the presented system.

Deep brain stimulation (DBS) has been recognized as an efficacious treatment for movement disorders. Its beneficial effects however may be lost due to skin complications such as erosions or infections over the implanted foreign material. We sought to document skin complications in the entire Parkinson’s disease patient population who received a DBS system at the Marburg/Kassel implantation centre since the start of our DBS program in January 2002 to analyze frequency, time course, and possible risk factors. We investigated 85 consecutive patients with Parkinson’s disease (PD) from a single center/single surgeon DBS series for the occurrence of skin complications and analyzed localization, time course, and possible risk factors. Mean follow-up was 3 years (range 1-7 years). In total, 21/85 patients (24.7%) suffered a total of 30 single skin complications. Sixty percent of all incidents occurred within the first post-operative year. Forty percent of all incidents occurred later than the first year following primary implantation. Complications involved the burr hole cap in 37%, the course of the cables in 33%, and the impulse generator (IPG) site in 30%. Six of 21 patients suffered recurring skin complications. Eight patients permanently lost their DBS system. Factor analysis for age, gender, disease duration, disease severity, the incidence of hypertension or diabetes as well as a 2-day period with externalized electrodes for continuous test stimulation did not have any statistically significant impact on skin complications. We conclude that (1) PD patients have a risk for skin complications after DBS as long as the system remains in situ and (2) there are at present no identifiable risk factors for skin complications after DBS, other than PD itself.

Background Endoscopic third ventriculostomy (ETV) is the treatment of choice for obstructive hydrocephalus. In some cases a reclosure of the ventriculostoma occurs. This could be caused by different reasons, such as operative technique, size of the stoma, scarring, or a persisting Liliequist membrane. Methods The databases of the Neurosurgical Department of the Philipps University Marburg and the International Neuroscience Institute Hannover have been explored. The medical reports of patients who suffered from hydrocephalus and were treated with ETV between 1990 and 2010 were reviewed, with special consideration of a nonpatent ventriculostoma and a repeated ETV. Results Of 148 patients with ETV, we had 14 patients in whom the stoma was not patent. In 8 of those, we performed a successful second ventriculostomy. Five patients were treated with application of a ventriculoperitoneal shunt. One patient died of an acute obstructive hydrocephalus due to the closure of the ventriculostoma. The success rate of repeat ETV has been 87.5%. Conclusions In cases of secondary closure of the stoma after ETV, an endoscopic reventriculostomy is recommended using the same operative approach and should be taken into consideration before the application of a cerebrospinal fluid diversion system.

According to their strategic location, intraaxial lesions of the foramen magnum may cause severe symptoms. The primary goal of surgery is to decompress the lower brain stem and upper cervical cord without additionally impairing the neurological function, or, as in vascular lesions, to eliminate the risk of recurrent bleeding. Secondary goals of surgery are to preserve the atlanto-occipital stability, to minimize traumatization of various muscles in the craniovertebral region, to preserve the sigmoid sinus and jugular bulb and to avoid air embolism or excessive venous bleeding during surgery. The most common intraaxial lesions encountered at the level of the foramen magnum are cavernous malformations, gliomas, ependymomas, and hemangioblastomas. They are located either in the medulla oblongata (up to the pontomedullary junction) or within the cervical cord at the level of C1. These lesions may be located either totally intraaxially, with or without contact to the surface of the brain stem or spinal cord, or, in other instances, they may be partially exophytic (1). Moreover, from the surgical point of view, particularly in terms of accessibility, lesions located in the dorsal and lateral region of the brain stem and spinal cord significantly differ from those located anteriorly or anterolaterally. Hemangioblastomas may sometimes involve the proximal intradural vertebral artery and its branches.

The region of the craniocervical junction is the site of various pathological lesions. Due to the complex topographical anatomy, performing surgery within this area requires great experience and knowledge in both spinal and skull-base anatomy. The most frequent tumors located within the craniocervical junction area are meningiomas. These lesions may occur in a great variety of appearances in terms of histological type, size, extension, insertion, vascularity, invasiveness, involvement of the vertebral artery, and growth pattern. Accordingly, the surgical removal of such tumors must be adequately adapted to all these variations. Apart from meningiomas, we have also treated a number of other lesions within this area such as neurinomas, ependymomas, hemangioblastomas, etc.

In this paper, a segmentation method for spherically-and elliptically-shaped objects is presented. It utilizes a user-defined seed point to set up a directed 3D graph. The nodes of the 3D graph are obtained by sampling along rays that are sent through the surface points of a polyhedron. Additionally, several arcs and a parameter constrain the set of possible segmentations and enforce smoothness. After the graph has been constructed, the minimal cost closed set on the graph is computed via a polynomial time s-t cut, creating an optimal segmentation of the object. The presented method has been evaluated on 50 Magnetic Resonance Imaging (MRI) data sets with World Health Organization (WHO) grade IV gliomas (glioblastoma multiforme). The ground truth of the tumor boundaries were manually extracted by three clinical experts (neurological surgeons) with several years (> 6) of experience in resection of gliomas and afterwards compared with the automatic segmentation results of the proposed scheme yielding an average Dice Similarity Coefficient (DSC) of 80.37±8.93%. However, no segmentation method provides a perfect result, so additional editing on some slices was required, but these edits could be achieved quickly because the automatic segmentation provides a border that fits mostly to the desired contour. Furthermore, the manual segmentation by neurological surgeons took 2-32 minutes (mean: 8 minutes), in contrast to the automatic segmentation with our implementation that took less than 5 seconds.

Objectives Recently, neurosurgeons have increasingly faced small intracerebral lesions in asymptomatic or minimally symptomatic patients. Here, we evaluated a series of four patients with nearly asymptomatic intraventricular tumors close to the corpus callosum that had been treated with the aid of an image-guided transcallosal approach. Patients and methods Four consecutive patients suffering from left intra- and paraventricular tumors were operated on via a contralateral interhemispheric transcallosal approach with the aid of neuronavigation. Our image-guided system directed: (1) the skin incision, (2) the interhemispheric dissection, and (3) the incision of the corpus callosum. Results Using the image-guided contralateral interhemispheric transcallosal approach to the left ventricle all lesions have been completely resected without the risk of damage to the dominant hemisphere. The callosal incision was kept as limited as possible (1.2–2.1 cm) depending on the size of the tumor. No postoperative neurological or neuropsychological deficit was observed in our series. Conclusion Neuronavigation facilitates a safe and targeted contralateral interhemispheric transcallosal approach to the dominant hemisphere's lateral ventricle. Our technique minimizes the risk of damage to the dominant hemisphere and requires only a limited opening of the corpus callosum, which might decrease the risk of neuropsychological morbidity.

Dural arteriovenous fistulas located in the vicinity of the jugular foramen are complex vascular malformations and belong to the most challenging skull base lesions to treat. The authors comprehensively analyze multiple features in a series of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb. Four patients who underwent surgery via the transcondylar approach to treat dural arteriovenous fistulas around the jugular foramen were retrospectively reviewed. Previously, endovascular treatment was attempted in all patients. The success of the surgical treatment was examined with postoperative angiography. Complete obliteration of the dural arteriovenous fistulas (DAVFs) was achieved in three patients, and significant flow reduction in one individual. All patients had a good postoperative outcome, and only one experienced mild hypoglossal nerve palsy. Despite extensive bone drilling, an occipitocervical fusion was necessary in only one patient with bilateral lesions. The use of an individually tailored transcondylar approach to treat dural arteriovenous fistulas at the region of the jugular foramen is most effective. This approach allows for complete obliteration of the connecting arterial feeders, and removal of bony structures containing pathological vessels.

Deep brain stimulation of the subthalamic nucleus is an important treatment option for advanced stages of idiopathic Parkinson's disease, leading to significant improvement of motor symptoms in suited patients. Hardware-related complications such as technical malfunction, skin erosion, and infections however cause patient discomfort and additional expense. The patient presented here suffered a putrid infection of the impulse generator site following only local dental treatment of apical parodontitis. Therefore, prophylactic systemic antibiotic treatment is recommended for patients with implanted deep brain stimulation devices in case of operations, dental procedures, or infectious disease.

Objective The purpose of this article is to focus for the first time on the operative management of a direct vertebral artery (VA)-posterior inferior cerebellar artery (PICA) end-to-end anastomosis in a partially thrombosed giant VA-PICA-complex aneurysm and to underline its usefulness as an additional treatment option. Methods The operative technique of a direct VA-PICA end-to-end anatomosis is described in detail. The VA was entering the large aneurysm sack. Distally, the PICA originated from the aneurysm sack-VA-complex. The donor and recipient vessel were cut close to the aneurysm. Whereas the VA was cut in a straight manner, the PICA was cut at an oblique 45-degree angle to enlarge the vascular end diameter. Vessel ends were flushed with heparinized saline and sutured. The thrombotic material inside the aneurysm sack was removed and the distal VA clipped, leaving the anterior spinal artery and brainstem perforators free. Results The patient regained consciousness without additional morbidity. Magnetic resonance imaging scans revealed a completely decompressed brainstem without infarction. The postoperative angiograms demonstrated a good filling of the anastomosed PICA. Conclusion Despite the caliber mistmatch of these two vessels the direct VA-PICA end-to-end anastomosis provides an accurate alternative in addition to other anastomoses and bypass techniques, when donor and recipient vessels are suitable and medullary perforators do not have to be disrupted.