H. Urbach

Tractography of Association Fibers Associated with Language Processing

IntroductionSeveral major association fiber tracts are known to be part of the language processing system. There is evidence that high angular diffusion-based MRI is able to separate these fascicles in a constant way. In this study, we wanted to proof this thesis using a novel whole brain “global tracking” approach and to test for possible lateralization.MethodsGlobal tracking was performed in six healthy right-handed volunteers for the arcuate fascicle (AF), the medial longitudinal fascicle (MdLF), the inferior fronto-occipital fascicle (IFOF), and the inferior longitudinal fascicle (ILF). These fiber tracts were characterized quantitatively using the number of streamlines (SL) and the mean fractional anisotropy (FA).ResultsWe were able to characterize the AF, the MdLF, the IFOF, and the ILF consistently in six healthy volunteers using global tracking. A left-sided dominance (LI > 0.2) for the AF was found in all participants. The MdLF showed a left-sided dominance in four participants (one female, three male). Regarding the FA, no lateralization (LI > 0.2) could be shown in any of the fascicles.ConclusionUsing a novel global tracking algorithm we confirmed that the courses of the primary language processing associated fascicles can consistently be differentiated. Additionally we were able to show a streamline-based left-sided lateralization in the AF of all right-handed healthy subjects.

Surpass Flow Diverter for Treatment of Posterior Circulation Aneurysms

BACKGROUND AND PURPOSE: Flow diverters for the treatment of posterior circulation aneurysms remain controversial. We aimed to identify factors contributing to outcome measures in patients treated with the Surpass flow diverter for aneurysms in this location. MATERIALS AND METHODS: We conducted an observational study of 53 patients who underwent flow-diverter treatment for posterior circulation aneurysms at 15 centers. Key outcome measures were mortality, complete aneurysm occlusion, and modified Rankin Scale score at follow-up. RESULTS: At follow-up (median, 11.3 months; interquartile range, 5.9–12.7 months), 9 patients had died, resulting in an all-cause mortality rate of 17.3% (95% CI, 7%–27.6%); 7 deaths (14%) were directly related to the procedure and none occurred in patients with a baseline mRS score of zero. After adjusting for covariates, a baseline mRS of 3–5 was more significantly (P = .003) associated with a higher hazard ratio for death than a baseline mRS of 0–2 (hazard ratio, 17.11; 95% CI, 2.69–109.02). After adjusting for follow-up duration, a 1-point increase in the baseline mRS was significantly (P < .001) associated with higher values of mRS at follow-up (odds ratio, 2.93; 95% CI, 1.79–4.79). Follow-up angiography in 44 patients (median, 11.3 months; interquartile range, 5.9–12.7 months) showed complete aneurysm occlusion in 29 (66%; 95% CI, 50.1%–79.5%). CONCLUSIONS: Clinical results of flow-diverter treatment of posterior circulation aneurysms depend very much on patient selection. In this study, poorer outcomes were related to the treatment of aneurysms in patients with higher baseline mRS scores. Angiographic results showed a high occlusion rate for this subset of complex aneurysms.

Freiburg Neuropathology Case Conference: A Patient with Chronic Nasal Obstruction

while listening to the patient, it became obvious that he had a nasal speech. Olfactometric testing demonstrated bilateral dysosmia; rhinomanometry showed a pronounced bilateral nasal obstruction. Pure tone audiometry revealed normal hearing results, while tympanometric testing demonstrated negative pressure on both sides. For the treatment of the nasopharyngeal lesion, initially an open approach via palatinal split was planned. Intraoperative examination of the tumor using an angled-view endoscope (30°) led to a modification in the surgical treatment concept. Based on the endoscopic finding that the tumor seemed to be petiolated at the rear pharynx wall, the surgical plan was changed to a transoral-endoscopic approach. Endoscopic transnasal examination showed a brownish mass in the nasopharynx with a plain surface, filling out this space completely (Fig. 1). The mass demonstrated pulsating movements synchronous to the patient’s pulse. Two slim catheters were positioned transnasally under endoscopic control and lead through the mouth. Due to this procedure, the surgeon was enabled to lift the soft palate to gain better transoral access toward the nasopharynx. The transoral-endoscopic approach allowed cautious palpation and movement of the tumor, thereby confirming the adherence of the tumor to the rear pharynx wall only by a broad tissue handle. Adhesions were not found either to the lateral parts or to the cranial part of the tumor. Under endoscopic guidance, the tissue handle was coagulated and successively excised using an especially bent and suction-including bipolar forceps as well as cold instruments. Intraoperatively, the tumor was moderately vascularized, in contrast to preoperative apprehension. Removal of the tumor was achieved in total after meticulous surgical preparation without any major bleeding. Terminal endoscopic examination evaluated a complete ablation of the tumor without any evidence of remaining tumor tissue or bleeding.

Freiburg Neuropathology Case Conference. A Mass Lesion of the Fourth Ventricle

cyst with its shiny white surface and waxen consistency. After incision of the tumor capsule, a tumor debulking was performed and the apex of the tumor was identified and removed to get access to the fourth ventricle. The upper and lateral part of the tumor could be easily dissected from the vermis and the tonsils and luxated downward. The lower part has a broad adhesion to the brainstem and could only be removed with microinstruments stepwise with great caution. As manipulation of the tumor capsule on the brainstem triggered electrophysiologic signals of the cranial nerves X and XII, parts of the capsule were left in place and signals returned to normal baseline. On microscopic inspection, a gross total resection could be achieved. A postoperative computed tomography (CT) confirmed this and showed no indications of bleeding. The patient was transferred to the neurosurgical intensive care unit and was extubated after 2 days when she recovered sufficient caudal cranial nerve function. Clinically, she had dysarthria and showed slightly reduced coughing and swallowing. Due to an intercurrent pneumonia with Escherichia coli, she had to be reintubated and ventilated under intravenous antibiotic treatment for 12 days. Dysarthria and swallowing due to a postoperative palatal palsy significantly improved after extubation under daily logopedic and physiotherapy treatment. The patient recovered well and was ambulatory with stable gait and no ataxia. She could be transferred into neurological rehabilitation in a clinically and neurologically stable condition.

Ruptured Fusiform Aneurysm of the Anterior Spinal Artery

Reports of anterior spinal artery (ASA) aneurysms are sparse in the English literature with only 10 cases of angiographically confirmed ruptured craniocervical ASA aneurysms (Table 1; [1–10]). In this location they usually present with symptoms of intracranial subarachnoid hemorrhage (SAH). There is no general consensus on the optimal treatment strategy of ASA aneurysms. Management carries a significant risk and different strategies (e.g. surgical trapping, resection, endovascular occlusion and conservative wait and see) have been proposed in case reports or mini-series [5, 6, 10]. Flow diverter stents (FDS) are usually used for treatment of large or giant wide-necked sidewall or fusiform aneurysms where the aneurysm is directly covered by the FDS. Here, we describe the successful endovascular treatment of a ruptured fusiform ASA aneurysm by hemodynamic remodeling with a FDS placed in the ipsilateral vertebral artery (VA).

Teaching Neuroimages: “Filling out” in Cavernous Hemangioma of the Cavernous Sinus

Cavernous sinus hemangiomas, which histologically correspond to cavernous (hem)angiomas (cavernomas), are rare benign mesenchymal (extra-axial) neoplasms of the cavernous sinus (female > male, mean age ca. 40–50 years, 3% of suprasellar tumors; [1–4]). Clinical presentation is variable and depends on the size of the tumor. Headache and retrobulbar pain are frequent. Less common symptoms are cranial neuropathies due to intracavernous nerve compression, loss of visual acuity caused by compression of the optic nerve and dizziness, probably related to blood flow impairment within the cavernous sinus and/or carotid artery [1, 3, 4]. Computed tomography (CT) usually reveals erosion and bone remodeling [5], indicating slow progression. This is in contrast to calvarial hemangiomas, which generally display (trabecular) calcifications [6]. The magnetic resonance imaging (MRI) typically shows T1w isointense and T2w hyperintense, strongly contrast-enhancing extraaxial masses [2, 5]. The pivotal sign of cavernous sinus hemangiomas is the edge to center enhancement (“filling in”) in dynamic contrast-enhanced MRI [2, 7]. Due to the strong contrast enhancement the differential diagnoses of cavernous sinus hemangiomas are meningiomas and schwannomas [1, 4].

Freiburg Neuropathology Case Conference: Tumor of the Mesiotemporal Lobe in a Child

An 11-year-old male patient presented after having sustained a seizure after sleep deprivation. The seizure was characterized by a prodromal phase with fixed gaze, loss of consciousness, and tonic-clonic contractions of the extremities. There were no neurological deficits in the clinical examination. Magnetic resonance imaging (MRI) of the central nervous system showed a right mesiotemporal lesion. A temporal craniotomy was performed with the patient under general anesthesia. The tumor was reached and removed through a subtemporal approach. The appearance of the tumor was grayish and firm. The patient had an uneventful postoperative course with no new neurological deficits. The postoperative MRI showed no residual tumor.

Freiburg Neuropathology Case Conference: Tumor Located in the Anterior Portion of the Third Ventricle

A 61-year-old female patient presented at our outpatient clinic with blurred vision and dizziness for the last 5 months. The symptoms were fluctuating, increasing in stress situations. Additionally, the patient noticed impaired concentration as well as mild headache and fatigue symptoms. An ophthalmological examination showed no restrictions in visual acuity or field. There was a singular episode of nausea without vomiting and no other clinical signs of increased intracranial pressure. Magnetic resonance imaging (MRI) showed a tumor of the third ventricle. A stereotactic biopsy was indicated to obtain a histopathological diagnosis. On admission the neurological status of the patient was normal. The preoperative hormone status showed no functional alteration of the pituitary gland, so a perioperative hormone supplementation was not necessary. The stereotactic biopsy was performed through a right frontal approach with the patient under general anesthesia. The operation was uneventful and there were no new neurological deficits after the procedure. A serum control of the hormone status showed stable parameters. The postsurgical course was regular and the patient could be discharged in a stable clinical condition.

Freiburg Neuropathology Case Conference: A Painless Mass Lesion of the Parietal and Occipital Bones

A 54-year-old male patient presented with a painless mass lesion of the parietal and occipital bone. He had realized the presence of the lesion about 15 years earlier. The size of the lesion remained relatively stable for a long period of time and started increasing only 3 years ago. Any neurological disorders, particularly headaches, or seizures were denied and the clinical examination was unremarkable. The lesion presented as a painless solid swelling, the overlying skin was intact and relocatable. The patient was operated on in a prone position with the head orthograde in a Mayfield skull clamp. Using a U-shaped incision around the lesion, skin and galea periosteum were dissected from the lesion, both of which were unremarkable. The whole lesion was depicted up to where apparently normal skull bone was visible, which was confirmed by neuronavigation. Using the template of the cranioplasty implant and neuronavigation the lesion was resected in several parts using a craniotome. The resulting bone edges were unremarkable. Adhesions of the lesion to the dura were separated using sharp dissection, the remaining dura looked inconspicuous. Intradural tumor growth was ruled out using intraoperative ultrasound. A PEEK cranioplasty implant (3di, Jena, Germany) was put in place and fixed with titanium platelets. Postoperative care

Osteophyte piercing of the dura

A 34-year-old man complained of sudden onset of orthostatic headache lasting for 2 weeks. Magnetic resonance imaging (MRI) of the head was normal, the cerebrospinal fluid (CSF) opening pressure was 6cm H20, and the body mass index (BMI) was 22.6kg/m2. Dynamic myelography (Fig. 1a) and computed tomography (CT) myelography (Fig. 1b, c) revealed a CSF leak at the Th2/3 level caused by a 3mm large penetrating osteophyte. Surgical repair (Fig. 1d) with resection of the osteophyte and ligation of the dural tear resulted in complete relief of the patient’s symptoms. Ventral, vertical dural tears are a typical cause of CSF leak-related intracranial hypotension [1]. Fluoroscopy or CT-guided epidural blood patch may lead to substantial improvement but is typically not sufficient to seal the leak and to get the patients free of symptoms [2]. Exact delineation of the dural tear by (repeated) dynamic myelography, dynamic CT myelography or digital subtraction myelography is mandatory. Dural tears are typically located along the lower cervical and thoracic spine [2] and patients have a low BMI [3].