Search

Background: Seizures as the unique initial manifestation of unruptured intracranial aneurysms have rarely been documented and not systematically described until now., Objective: The purpose of this large retrospective analysis was to focus on the incidence of primary epileptogenic aneurysms and the influence of treatment on epilepsy., Methods: Within a 16-year period, 347 unruptured aneurysms were surgically treated at centers in Munich (1992-2002) and Düsseldorf (2003-2008), Germany. Of this patient population, 9 patients presented exclusively with epileptic seizures or epileptic equivalents. In 3 of them, a high-lying internal carotid artery aneurysm was diagnosed that was buried in the parahippocampal gyrus. In 4 patients, a middle cerebral artery aneurysm also created contact with the mediotemporal lobe adjacent to the parahippocampal gyrus. An anterior communicating artery aneurysm and a pericallosal artery aneurysm were diagnosed in 2 additional patients. Two patients with a middle cerebral artery aneurysm were initially incompletely occluded with Guglielmi detachable coils and continued to have epilepsy after the intervention. In all but 1 patient, the aneurysms were clipped and completely removed., Results: In all 8 patients operated on, there was no sign of hemorrhage intraoperatively but cortical gliosis was seen around the dome of the aneurysm. In all cases, the aneurysm and the surrounding gliosis, if existent, were surgically removed. Freedom from seizures without medication resulted for all patients after microsurgery., Discussion: Seizures as a presenting symptom of unruptured intracranial aneurysms are rare. There seems to be a preponderance of aneurysms anatomically related to the temporomedial region. Elimination of the aneurysm and perifocal gliosis provides the possibility of a cure for the epilepsy.

Objective: A spinal perimedullary arteriovenous fistula (PMAVF) is a direct fistula of one or more spinal arteries into the perimedullary venous network with reversed venous flow and subsequent venous congestion of the spinal cord. The therapeutic goal of surgery is to normalize the venous drainage by obliterating the fistula. Strictly ventral lesions typically require an anterior approach to ensure adequate exposure of the fistula as well and the preservation of the physiological blood supply to the spinal cord., Clinical Presentation: We present a case of a ventral PMAVF at the level of T10 with feeders from the anterior spinal artery, caudally draining veins on the ventral spinal cord, and a dilated transmedullary vein filling cranially draining veins on the dorsal aspect of the spinal cord., Technique: The dilated transmedullary vein was approached by a laminectomy. The vein was coagulated, and the gliotic channel was used to approach the ventral fistula site from the dorsal surface of the spinal cord. Complete obliteration of the fistula was achieved, and the preoperative neurological deficit improved., Conclusion: We conclude that transmedullarly draining veins offers a possible dorsal approach for the occlusion of some ventral PMAVFs, thus avoiding more complex anterior approaches to the ventral spinal cord.

Objective: The tentorial notch can be contained within a transversal line made in front of the cerebral peduncles and another line through the posterior border of the quadrigeminal plate into the anterior, middle and posterior parts. Different approaches to the tentorial incisura have been established. The subtemporal approach represents one of those options. Since morphometrical analyses of this approach in this region have not yet been performed, the aim of the present study was to measure the surgical corridor along these borders., Methods: Fifty-three magnetization prepared rapid acquisition gradient echo-sequences of individual brains without pathological lesions were analyzed. For this study, an axial section along the pontomesencephalic sulcus and two coronal sections along the above-described borders were measured using a program specially written by one of the coauthors to obtain various parameters. A triangle circumscribing the surgical corridor was delimited by exactly defined anatomic landmarks for the coronal section, and the depths of the temporal lobe at the incisural borders were measured for the axial section., Results: Various data are given concerning the surgical corridor of a subtemporal approach to the tentorial incisura. The different shapes of this corridor to the incisural region were recorded. According to our measurements, four different types of the temporal lobe could be differentiated., Conclusion: Knowledge of these distances and various contours of the path is crucial to avoid brain damage during retraction or manipulation. The curvature of the floor of the middle cranial fossa is highly variable and thus determines the surgical path chosen.

Objective: This is the first description of a severe and sometimes fatal complication after uneventful intracranial surgery. The clinical presentation and imaging features mimic those of global cerebral hypoxia. Extensive investigations were performed to discover the pathogenesis., Methods: Seventeen cases of pseudohypoxic brain swelling (PHBS) were collected from our institution and from various other neurosurgical departments and were studied for common features. PHBS can occur in a mild, moderate, or severe degree. It is characterized by a very early postoperative onset of clinical deterioration (clouded or lost consciousness and pupillary abnormalities), in association with typical bilateral computed tomographic or magnetic resonance imaging changes (hypodensities or altered intensities in the basal ganglia and/or thalamus). The following variables were considered: age, primary pathological lesion and intracranial location, previous cranial surgery, anesthetic risk, type of anesthesia, approach and duration of surgery, intraoperative observations, technical monitoring results, and blood gas analyses. The results of postoperative computed tomography and various other imaging studies, intracranial pressure measurements, transcranial Doppler sonography, toxicological analyses, brain and muscle biopsies, and autopsies were also considered in the investigation. Several countermeasures were instituted and evaluated., Results: Anoxemic and ischemic hypoxia was excluded as a cause of PHBS. No evidence was found for inhibition of the respiratory chain, mitochondriopathy, poisoning, or adverse effects of drugs., Conclusion: Indications of intracranial hypotension, induced by suction drainage, being the main pathomechanism of PHBS are discussed. A serious warning is issued regarding the use of suction drainage after intracranial surgery.

Objective: The present study was undertaken to describe the clinical and prospective neuropsychological results for our group of 30 patients who were treated using a transcallosal interforniceal-transforaminal microsurgical approach., Methods: The transcallosal interforniceal and transcallosal-transforaminal approaches were used to treat 30 patients with space-occupying lesions located in the anterior part of the third ventricle. We used a modified anterior transcallosal microsurgical approach, as described recently. The patients underwent extensive, pre- and postoperative, prospective neuropsychological testing, using a specially designed test battery., Results: Twenty-three of 30 patients (77%) experienced excellent clinical outcomes (Glasgow Outcome Scale Grade V). The surgical procedures described in this report did not themselves impair attentional function. In both the early and late postoperative neuropsychological testing sessions, deficits in verbal memory were only rarely observed and were not noted to be correlated with the surgical procedures. The most relevant neuropsychological results for individual patients are reported in detail., Conclusion: The approach described here can be successfully used for the resection of various space-occupying lesions in the anterior part of the third ventricle. The anatomic landmarks we recently defined and described (for example, the midline vessel on the trunk of the corpus callosum, to direct the callosotomy) guide the surgical path. Furthermore, we recommend the use of neuropsychological test batteries for both scientific and rehabilitative purposes.

Objective: The ability to visualize median-sagittal brain structures by magnetic resonance imaging (MRI) improves the planning for surgical removal of lesions located in and around the third ventricle. The transcallosal approach is the most appropriate path to the anterior part of the third ventricle. The present study was undertaken to obtain normative morphometric data, derived from sagittal MRI scans, which are necessary for operation planning that takes into account the surgical microanatomy and landmarks encountered during this approach., Methods: The morphometric evaluation was performed on 72 median-sagittal MRI scans. The surface landmarks for the corridor were the two points, P5 and P7, located 5 and 7 cm anterior to the central sulcus, respectively. With these two points on the cortical surface as references, a variety of measurements were made to provide quantitative information about distances between brain structures encountered during the surgical approach. In addition, various parameters were determined to characterize the different shapes of the fornix and the different types of forniceal insertion., Results: The following measurements (means) were obtained: 1) the distance between P5/P7 and the cingulate sulcus was 25.76 mm (range, 17.113-42.73 mm) with reference to P5, and 25.41 mm (range, 12.91-36.29 mm) with reference to P7; 2) the distance between the cingulate sulcus and the corpus callosum was 12.91 mm (range, 7.19-22.60 mm) with reference to P5, and 12.92 mm (range, 6.75-23.37 mm) with reference to P7; 3) the height of the corpus callosum was 6.22 mm (range, 3.07-9.00 mm) with reference to P5, and 6.92 mm (range, 3.50-13.57 mm) with reference to P7; 4) the distance between the anterior commissure and the foramen of Monro was 6.78 mm (range, 1.86-14.57 mm), independent of P5 and P7; 5) the distance between the lower margin of the corpus callosum and the upper insertion point of the fornix was 12.44 mm (range, 2.71-26.13 mm) with reference to P5, and 13.34 mm (range, 3.74-27.58 mm) with reference to P7; 6) the distance between the lower margin of the corpus callosum and the lower insertion point of the fornix was 18.08 mm (range, 9.47-29.71 mm) with reference to P5, and 18.58 mm (range, 10.48-30.40 mm) with reference to P7; and 7) the distance between the lower margin of the corpus callosum and the anterior commissure was 23.46 mm (range, 11.98-32.70 mm) with reference to P5, and 22.89 mm (range, 11.05-33.04 mm) with reference to P7. Four different insertion types between the fornix and the corpus callosum were noted and classified., Conclusion: Morphometric data concerning the surrounding structures of the third ventricle have received very little attention in the literature. This morphometric study permitted definition of the surgical corridor to the third ventricle by preserving important anatomic structures such as the motor strip, genu of the corpus callosum, forniceal commissure (hippocampal commissure), anterior commissure, and forniceal columns. The detailed morphometric data obtained on median-sagittal MRI scans of the brain structures involved in the transcallosal interforniceal and/or transcallosal transforaminal approach allow for exact planning of the surgical approach.

Objective: The ability to visualize median-sagittal brain structures by magnetic resonance imaging improves planning for surgery to treat lesions of the third ventricle. The most appropriate path to the third ventricle is the transcallosal approach. The present study was undertaken to describe the surgical anatomy and landmarks encountered during this approach., Methods: The transcallosal-interforniceal approach was undertaken in 30 formalin-fixed brains using an operating microscope. The surface landmarks for the approach pathway were the two points, P5 and P7, located 5 and 7 cm anterior to the central sulcus, respectively. Using these two points on the cortical surface as references, a variety of measurements were made to provide quantitative information about distances between brain structures that are encountered during the surgical approach. Measurements that were made include the following: 1) the distance between P5 and the cingulate sulcus, 2) the distance between the cingulate sulcus and the corpus callosum, 3) the height of the corpus callosum, 4) the distance between the anterior commissure and the foramen of Monro, and 5) the distance between the lower margin of the corpus callosum and the fornix., Results: Mean values for these key measurements were as follows: 1) 23.96 mm (range, 15.0-32.0 mm); 2) 13.50 mm (range, 8.0-20.0 mm) with reference to P5 and 12.73 mm (range, 16.0-18.0 mm) with reference to P7; 3) 6.12 mm (range, 4.0-8.0 mm) with reference to P5 and 6.60 mm (range, 4.0-9.0 mm) with reference to P7; 4) 4.96 mm (range, 2.5-10.0 mm), independent of P5 and P7; and 5) 8.46 mm (range, 3.0-16.0 mm) with reference to P5 and 11.04 mm (range, 6.0-22.0 mm) with reference to P7., Conclusion: The detailed quantitative information obtained in this study about the interforniceal approach permitted definition of surgical approach pathways that preserve important anatomic structures, such as the motor strip, genu of the corpus callosum, fornical commissure (hippocampal commissure), anterior commissure, and fornical columns. The approach through this surgical corridor can easily be planned and performed in individual cases using median-sagittal magnetic resonance imaging scans.

Objective and Importance: Endodermal cysts are rare lesions that primarily affect the spinal cord. Only a few reports have been published that describe intracranial endodermal cysts, and, in most of the cases, the cysts were located in the posterior fossa. To our knowledge, there have been no reports of endodermal cysts of the third ventricle., Clinical Presentation: A symptomatic endodermal cyst of the third ventricle in a 28-year-old man is presented. The patient demonstrated signs of increased intracranial pressure and reported a progressive loss of vision in his right eye. Neuroradiological imaging revealed obstructive hydrocephalus and a lesion inside the third ventricle measuring 1.2 cm in diameter and occluding the interventricular foramen., Intervention: The cyst was successfully removed via a transcallosal-transforaminal approach. Postoperatively, the patient developed bifrontal effusions for some days. Hydrocephalus was diminished, but his vision had only slightly improved., Conclusion: To our knowledge, this is the first published report of an endodermal cyst occurring in the third ventricle, and represents a further example of the broad spectrum of lesions affecting that location.