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Background: Symptomatic patients with a brainstem cavernoma are treated surgically with increasing frequency. Generally, the patient's benefit from this difficult surgical intervention is quantified by the assessment of neurological symptoms., Objective: To document the beneficial effect of surgery in a larger patient population by assessing the postoperative quality of life (QoL)., Methods: In a series of 71 surgically treated patients, a detailed neurological status was assessed by Patzold Rating and Karnofsky Performance Status Scale. Patients rated their QoL with the Short Form 36 Health Survey. To document the effect of surgery on QoL, we devised a supplementary questionnaire. The last 24 patients completed Short Form 36 Health Survey pre- and postoperatively., Results: Karnofsky Performance Status Scale improved in 44 of 71 surgical patients (62%), remained unchanged in 19 (27%), and deteriorated in 8 (11%) individuals. Patzold Rating showed a more detailed picture of the neurological symptoms. It correlated significantly with Karnofsky Performance Status Scale, which underscores its usefulness for patients with brainstem lesions. In the Short Form 36 Health Survey score, the Mental Component Summary improved with surgery (paired test, P = .015). In addition, 58 individuals (82%) declared a clear subjective benefit of surgery., Conclusion: The results of this large series support the notion that microsurgical removal of a brainstem cavernoma represents an effective therapy in experienced hands and is generally associated with good clinical outcome, both neurologically and in terms of QoL.

Background: Surgical exposure of intrinsic brainstem lesions through the floor of the 4th ventricle requires precise identification of facial nerve (CN VII) fibers to avoid damage., Objective: To assess the shape, size, and variability of the area where the facial nerve can be stimulated electrophysiologically on the surface of the rhomboid fossa., Methods: Over a period of 18 months, 20 patients were operated on for various brainstem and/or cerebellar lesions. Facial nerve fibers were stimulated to yield compound muscle action potentials (CMAP) in the target muscles. Using the sites of CMAP yield, a detailed functional map of the rhomboid fossa was constructed for each patient., Results: Lesions resected included 14 gliomas, 5 cavernomas, and 1 epidermoid cyst. Of 40 response areas mapped, 19 reached the median sulcus. The distance from the obex to the caudal border of the response area ranged from 8 to 27 mm (median, 17 mm). The rostrocaudal length of the response area ranged from 2 to 15 mm (median, 5 mm)., Conclusion: Facial nerve response areas showed large variability in size and position, even in patients with significant distance between the facial colliculus and underlying pathological lesion. Lesions located close to the facial colliculus markedly distorted the response area. This is the first documentation of variability in the CN VII response area in the rhomboid fossa. Knowledge of this remarkable variability may facilitate the assessment of safe entry zones to the brainstem and may contribute to improved outcome following neurosurgical interventions within this sensitive area of the brain.

Background: Patients with cerebral cavernomas have an estimated risk of the development of epilepsy of 1.5% to 2.4% per patient-year., Objective: To clarify the predictive value of different risk factors for epilepsy in patients with supratentorial cavernomas., Methods: We retrospectively analyzed data of 109 patients with supratentorial cavernomas. The correlation of epilepsy with the variables of single or multiple cavernomas, sex, age, side, cortical involvement, mesiotemporal archicortical vs neocortical involvement, lobar location of neocortical cavernomas, the presence of a hemosiderin rim and of edema, and the maximal diameters of cavernoma, hemosiderin rim, and edema, if present, were calculated using univariate and multivariate penalized likelihood logistic regression models., Results: Cortical involvement was the most relevant risk factor for epilepsy (P < .0001). No patient with a subcortical cavernoma presented with epilepsy. Epilepsy was more common in patients with mesiotemporal archicortical cavernomas than in patients with neocortical cavernomas (P = .02), whereas the lobar location of neocortical cavernomas was not significantly associated with the risk of the development of epilepsy. In the multivariate analysis, a greater diameter of the cavernoma, the absence of edema, and localization in the left hemisphere were also associated with the occurrence of epilepsy (P < .05)., Conclusion: The epileptogenicity of supratentorial cavernomas depends on cortical, especially mesiotemporal archicortical, involvement. Exclusively subcortical cavernomas are highly unlikely to cause epilepsy. This information is helpful in counseling patients with cavernomas regarding their risk of epileptic seizures and in patients with multiple cavernomas and epilepsy to generate a valid hypothesis of which cavernoma may cause epilepsy.

Objective: Microsurgical resection or ventriculoperitoneal shunt placement was for a long time the only means of treatment for patients with colloid cysts. In the past few years, however, endoscopic procedures have gained increasing significance and have been used more widely. Long-term results are now available for the first time, which enabled us to evaluate this method and assess its future relevance., Methods: Twenty patients with symptomatic colloid cysts of the third ventricle have been treated endoscopically in our department during the past 10 years. Retrospective analysis and follow-up of the patients' clinical and radiological outcomes were performed., Results: In the early postoperative period, 18 patients had excellent outcomes, with clinical signs improving immediately. One patient experienced intraoperative hemorrhage followed by temporary postoperative psychosis and IIIrd cranial nerve palsy. Another patient remained shunt-dependent because of aseptic meningitis after the endoscopic procedure. In the long-term follow-up, one patient had to be reoperated to treat cyst recurrence. The operative time was strongly dependent on the cyst material as well as on the surgeon's experience with endoscopic techniques; it varied between 60 and 300 minutes (mean operative time, 200 min). The average hospitalization time was 9 days. Long-term follow-up ranging from 1 to 10 years showed a clear benefit in each patient. In three individuals with pre- and postoperative short-term memory deficits and in one patient who complained of headaches, symptoms resolved gradually during the first few months after surgery. The patient with intraoperative hemorrhage complained of slight permanent short-time memory deficit. The analysis of postoperative computed tomographic and magnetic resonance imaging scans revealed a remaining cyst wall in the majority of patients and an inconsistent decrease in ventricular size. Postoperative cine magnetic resonance imaging studies showed normalization of cerebrospinal fluid flow in 17 patients., Conclusion: Continued improvement of endoscopic techniques and instruments, together with good long-term results in endoscopically treated patients, have established this method as an alternative to microsurgical techniques and might even set a new standard for treatment.

Objective: Surgical treatment of cavernomas arising in the insula is especially challenging because of the proximity to the internal capsule and lenticulostriate arteries. We present our technique of image guidance for operations on insular cavernomas and assess its clinical usefulness., Methods: Between 1997 and 2003, with the guidance of a frameless stereotactic system (BrainLab AG, Munich, Germany), we operated on eight patients who harbored an insular cavernoma. Neuronavigation was used for 1) accurate planning of the craniotomy, 2) identification of the distal sylvian fissure, and, finally, 3) finding the exact site for insular corticotomy. Postoperative clinical and neuroradiological evaluations were performed in each patient., Results: The navigation system worked properly in all eight neurosurgical patients. Exact planning of the approach and determination of the ideal trajectory of dissection toward the cavernoma was possible in every patient. All cavernomas were readily identified and completely removed by use of microsurgical techniques. No surgical complications occurred, and the postoperative course was uneventful in all patients., Conclusion: Image guidance during surgery for insular cavernomas provides high accuracy for lesion targeting and permits excellent anatomic orientation. Accordingly, safe exposure can be obtained because of a tailored dissection of the sylvian fissure and minimal insular corticotomy.

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.

Objective: The combination of classic neuronavigation and intraoperative ultrasound is a recent innovation in image guidance technology. However, this technique requires two hardware components (neuronavigation and an ultrasound system). It was the aim of the study to describe a new simplified technology of a so-called one-platform navigation system developed by our institution in collaboration with the industry and to demonstrate its range of various applications., Methods: An ultrasound device (IGSonic; BrainLAB, Munich, Germany) is integrated into the VectorVision2 navigation system (BrainLAB, Munich, Germany). The IGSonic Probe 10V5 is connected to the VectorVision Navigation station via an IGSonic Device Box. Once the ultrasound probe is calibrated, the navigated ultrasound displays the sonographic image of the intracranial anatomy on the navigation screen in a composed overlay fashion. It might depict vascular structures within the ultrasound plane by a duplex mode. Ultrasound can also be operated independently from navigation., Results: The VectorVision2 system combines intraoperative ultrasound data sets with preoperatively acquired neuronavigation data sets in plug and play fashion. The system provides a cost-effective intraoperative imaging modality that offers a good anatomic orientation by various composite images, including the display of the amount of brain shift. In our institution, the comprehensible interface led to a routine use of the technology by several neurosurgeons who had not been familiar with the ultrasound technology before., Conclusion: The integration of an ultrasound device into an existing navigation system has been successfully developed. The system offers a friendly user interface and cost-effective intraoperative imaging feedback. Although brain shift can be visualized by an image overlay technology as demonstrated by the present system, future developments should aim at fusion techniques of both intra- and preoperative image data sets.

Objective: In previous studies, we documented a marked neoangiogenesis and endothelial proliferation in cerebral arteriovenous malformations (AVMs) that were embolized before surgery compared with those that were not embolized. We hypothesized that embolization caused a local hypoxia that promotes neoangiogenesis as a possible pathomechanism. To support this hypothesis, we now examined the angiogenesis-related proteins in a larger cohort of patients. In addition, we investigated hypoxia-inducible factor-1 alpha as a possible protein operative during neoangiogenesis of cerebral AVMs., Methods: Paraffin-embedded specimens of 56 AVMs obtained from surgical resection and 14 brain tissue controls were immunohistochemically stained with antibodies to proliferating cell nuclear antigen, MIB-1, vascular endothelial growth factor, Flk1, and hypoxia-inducible factor-1 alpha by standard protocols., Results: In AVMs treated with embolization before surgery (n = 35, 63%), the expression of hypoxia-inducible factor-1 alpha (P = 0.0101) and vascular endothelial growth factor (P = 0.0007) was significantly higher (Fisher's exact test) than in patients who did not have previous endovascular treatment. Differences in the expression of Flk-1 (P = 0.0798) and proliferating cell nuclear antigen (P = 0.0423) were in the same direction but were not significant when corrected for multiple testing., Conclusion: Our results provide circumstantial evidence that a partial occlusion of cerebral AVMs might induce local hypoxia-related neoangiogenesis. To support these data, future animal studies should be performed.

Objective: Surgical treatment of cavernomas arising in the insula is especially challenging because of the proximity to the internal capsule and lenticulostriate arteries. We present our technique of image guidance for operations on insular cavernomas and assess its clinical usefulness., Methods: Between 1997 and 2003, with the guidance of a frameless stereotactic system (BrainLab AG, Munich, Germany), we operated on eight patients who harbored an insular cavernoma. Neuronavigation was used for 1) accurate planning of the craniotomy, 2) identification of the distal sylvian fissure, and, finally, 3) finding the exact site for insular corticotomy. Postoperative clinical and neuroradiological evaluations were performed in each patient., Results: The navigation system worked properly in all eight neurosurgical patients. Exact planning of the approach and determination of the ideal trajectory of dissection toward the cavernoma was possible in every patient. All cavernomas were readily identified and completely removed by use of microsurgical techniques. No surgical complications occurred, and the postoperative course was uneventful in all patients., Conclusion: Image guidance during surgery for insular cavernomas provides high accuracy for lesion targeting and permits excellent anatomic orientation. Accordingly, safe exposure can be obtained because of a tailored dissection of the sylvian fissure and minimal insular corticotomy.

Objective: To evaluate technical and methodological aspects of intraoperative spinal digital subtraction angiography (ISDSA) in our clinical practice and to assess its practicability, safety, and accuracy for the surgical treatment of spinal vascular malformations., Methods: Between August 1997 and February 2002, a total of 30 patients were treated either surgically (n = 18) or endovascularly (n = 12) for spinal vascular lesions at our institution. The clinical records of five patients who underwent ISDSA were analyzed retrospectively. The thoracic segment was involved in three patients and the medullary cone in two., Results: ISDSA could be performed in four cases. In one patient, the segmental artery could not be probed sufficiently while the patient was prone. No complications occurred from the application of ISDSA. The method was beneficial for the neurosurgeon in all but one patient because the vascular anatomy of the malformation was shown with respect to the surgical approach, including the nidus, and immediate resection control could be performed before wound closure. The duration of the procedure was prolonged by 45 minutes on average., Conclusion: ISDSA is safe and effective, especially in surgery for complex vascular and recurrent malformations. Benefits to the patient outweigh the additional expense and prolongation of the surgical procedure.

Objective: Microsurgical resection or ventriculoperitoneal shunt placement was for a long time the only means of treatment for patients with colloid cysts. In the past few years, however, endoscopic procedures have gained increasing significance and have been used more widely. Long-term results are now available for the first time, which enabled us to evaluate this method and assess its future relevance., Methods: Twenty patients with symptomatic colloid cysts of the third ventricle have been treated endoscopically in our department during the past 10 years. Retrospective analysis and follow-up of the patients' clinical and radiological outcomes were performed., Results: In the early postoperative period, 18 patients had excellent outcomes, with clinical signs improving immediately. One patient experienced intraoperative hemorrhage followed by temporary postoperative psychosis and IIIrd cranial nerve palsy. Another patient remained shunt-dependent because of aseptic meningitis after the endoscopic procedure. In the long-term follow-up, one patient had to be reoperated to treat cyst recurrence. The operative time was strongly dependent on the cyst material as well as on the surgeon's experience with endoscopic techniques; it varied between 60 and 300 minutes (mean operative time, 200 min). The average hospitalization time was 9 days. Long-term follow-up ranging from 1 to 10 years showed a clear benefit in each patient. In three individuals with pre- and postoperative short-term memory deficits and in one patient who complained of headaches, symptoms resolved gradually during the first few months after surgery. The patient with intraoperative hemorrhage complained of slight permanent short-time memory deficit. The analysis of postoperative computed tomographic and magnetic resonance imaging scans revealed a remaining cyst wall in the majority of patients and an inconsistent decrease in ventricular size. Postoperative cine magnetic resonance imaging studies showed normalization of cerebrospinal fluid flow in 17 patients., Conclusion: Continued improvement of endoscopic techniques and instruments, together with good long-term results in endoscopically treated patients, have established this method as an alternative to microsurgical techniques and might even set a new standard for treatment.

Objective: Hemorrhage control in endoscopic neurosurgery is critical because of the lack of suitable instruments for coagulation. One reason for this problem is that miniaturization of the instruments is still a technical problem. In this article, we present a solution: the use of bipolar microforceps with a small diameter of 1.5 mm., Methods: With the use of modern synthetic and metallic materials, the construction of the bipolar microforceps was designed without the use of mechanical joints. All movable elements are integrated within the instrument shaft. This design provides optimal visibility of the operating field because the sheath has a diameter of only 1.5 mm along its entire length. Therefore, this instrument is compatible with most working channels of neuroendoscopes., Results: The new, joint-free design of the forceps and the electric insulation of the branches were the technical innovations that led to the development of this novel, multipurpose instrument., Conclusion: This new instrument may enhance endoscopic resection and shrinkage of cystic lesions and may offer new possibilities in endoscopic tumor resection and the treatment of hemorrhage.

Objective: The important role played by nitric oxide (NO) in the maintenance of cerebral arterial tone, both in the resting state and after injury, has been demonstrated, but the role of NO in spinal arteries is unknown. The aim of this study was to verify, by topical application of a NO synthase inhibitor in vivo, the hypothesis that NO plays an important role in the maintenance of spinal arteriolar tone., Methods: Closed spinal windows were prepared at the C6 level, for observation of arteriolar reactivity. Male Wistar rats were divided into four groups in the resting state and three groups in the compressed state (which was produced by increasing the intrathecal window pressure). The control group underwent superfusion of artificial cerebrospinal fluid into the spinal window. The nitro-L-arginine-methyl ester (L-NAME) and nitro-D-arginine-methyl ester groups underwent superfusion of the NO synthase inhibitor L-NAME and its inactive enantiomer nitro-d-arginine-methyl ester, respectively. The L-NAME/S-nitroso-acetylpenicillamine (SNAP) group underwent mixed superfusion of L-NAME and the direct NO donor SNAP, for investigation of the effects of an exogenous NO donor., Results: In the resting state, the arterioles constricted significantly in the L-NAME group, compared with values before L-NAME superfusion and those for the other groups. In the L-NAME/SNAP group, the arterioles dilated significantly after SNAP superfusion, compared with values before superfusion and those for the other groups. In the compressed state, the arterioles dilated after compression in all three groups but the dilation was significantly attenuated in the L-NAME group, compared with values for the control and nitro-D-arginine-methyl ester groups., Conclusion: It is suggested that NO plays an important role in the maintenance of spinal arteriolar tone in the resting and compressed states of the spinal cord.

Objective: Monitoring of the oculomotor system during cranial base or brainstem surgery requires extraocular intraorbital insertion of electromyography electrodes. We investigated the use of image-guidance technology for anatomically correct intraorbital electrode placement., Methods: For neuronavigation, an optical tracking system was used in a standard fashion. Needle electrodes were inserted percutaneously into the lateral rectus, inferior rectus, and superior oblique muscle along the axis of a hand-held pointer or by means of an electrode applicator to allow direct tracking with the navigation system. Electromyographic monitoring was performed by multichannel recordings of free running or evoked activity from the selected muscles., Results: We have used this method in 10 patients; 5 had cranial base tumors and 5 underwent operations for brainstem lesions. No additional instruments or resources were required compared with the routine setup, and no intraorbital structures were injured. Successful monitoring of oculomotor, trochlear, or abducent nerve function was possible in each case., Conclusion: This method may have the potential to increase the safety and success rate of intraoperative electro-ophthalmography during microsurgery focused on preservation of neurological function.

Objectives: An in vivo closed spinal window technique in rats was designed for observing the spinal microcirculation, such as the change of vessel diameter, leukocyte adhesion, and red blood cell (RBC) velocity, which has been very rarely examined in vivo in the spinal cord., Methods: We made a very precise closed spinal window with a laminectomy at the C5 level using a dental acrylic resin and a cover glass (7 mm in diameter). Through this closed window, the dorsal surface of the rat cervical cord was observed with a video microscope, and the fluorescent images of rhodamine 6G-labeled leukocytes and fluorescein isothiocyanate-labeled RBCs were recorded and analyzed with a silicon-intensified target tube camera (30 frames/s) and an image-intensified high-speed video camera system (1000 frames/s)., Results: During CO2 inhalation, the pial arterioles responded with vasodilation of 12.4+/-10.4% (P<0.01) in 11 arterioles of seven rats. The adhering leukocytes significantly increased in 41 venular segments of seven rats after superfusion of the neutrophil chemoattractant, N-formyl-methionine-leucine-phenylalanine solution for 15 minutes (P<0.001) but not after superfusion of only artificial cerebrospinal fluid for 15 minutes. During these experiments, no adhering leukocyte was seen in the pial arterioles. Fluorescein isothiocyanate-labeled RBCs look like shooting stars in arterioles with silicon-intensified target tube camera processing at 30 frames per second, but individual fluorescein isothiocyanate-labeled RBCs could be recognized frame by frame with the image-intensified high-speed video camera system. In 13 arterioles of four rats, the RBC velocity was 5.3+/-2.0 mm per second., Conclusion: This closed spinal window technique in rats is available and applicable for the study of the spinal microcirculation, such as the pathophysiology of a secondary injury.

A new experimental model is described that uniquely allows the in vivo observation and quantification of vascular caliber changes on the dorsal surface of the feline spinal cord. The model consists of a rectangular Plexiglas window that is sutured to the lumbar dura and is supported by a special holder. Inlet and outlet tubes attached to the window serve for topical applications of mock cerebrospinal fluid or vasoactive agents to the surface of the cord and for continuous monitoring of intrathecal pressure. Pial vessels below the window were observed at 200-fold magnification with the aid of a microvideo camera. Spinal arterioles reacted to hypercarbia and superfusion with acetylcholine solution in a manner similar to cerebral arterioles. Tests with increased intrathecal pressure showed that the window remained watertight between 25 and 130 mm Hg, with an average leakage pressure of 57.8 +/- 33.5 mm Hg. To promote the use of this model in other laboratories, the authors give a detailed description of the closed spinal window preparation and report their experiences gained from 50 experiments. It is concluded that the closed spinal window is a highly reproducible model, suitable for the study of the feline spinal microcirculation for several hours in vivo.

The authors review their experience with a dorsolateral approach to the anterior rim of the foramen magnum and adjacent region. The operative technique includes exposure of the vertebral artery at C1, partial resection of the occipital condyle and lateral atlantal mass, and extradural drilling of the jugular tubercle. This approach has been applied in six patients who harbored intradural space-occupying lesions located ventral to the lower brain stem. Excision of the neoplasm was virtually total in all but one patient, in whom biopsy was the primary goal of the intervention. No morbidity and no mortality were associated with this approach. The main advantage of the dorsolateral, suboccipital, transcondylar route is the direct view it offers to the anterior rim of the foramen magnum without requiring brain stem retraction.