Ansgar Berlis

A Novel, Self-Expanding, Nitinol Stent in Medically Refractory Intracranial Atherosclerotic Stenoses: The Wingspan Study

Background and Purpose— The purpose of this study was to assess the safety and performance of the Wingspan stent system and Gateway percutaneous transluminal angioplasty balloon catheter in the treatment of high-grade, intracranial atherosclerotic lesions in patients who had failed medical therapy. Methods— In this prospective, multicenter, single-arm study, medically refractory patients with a modified Rankin score ≤3 and recurrent symptoms attributable to angiographically demonstrated intracranial stenosis ≥50% in a vessel 2.5 to 4.5 mm in diameter were enrolled. Intracranial lesions were predilated with an undersized Gateway balloon catheter to 80% of the native vessel diameter, followed by deployment of the self-expanding Wingspan stent to facilitate further remodeling of the atherosclerotic plaque and to maintain vessel patency. Neurologic examinations and angiograms were performed at 6 months after the procedure. Results— Among the 45 patients enrolled, the degree of stenosis was reduced from a baseline of 74.9±9.8% to 31.9±13.6% after stenting and 28±23.2% at the 6-month follow-up. The 30-day composite ipsilateral stroke/death rate was 4.5% (2/44); at the 6-month follow-up, the ipsilateral stroke/death rate was 7.0%, the rate for all strokes was 9.7%, and all-cause mortality was 2.3%. Physician-reported follow-up in 43 patients (average of 13 months) conducted outside the study protocol (not adjudicated by the clinical event committee) reported 1 additional ipsilateral stroke. Conclusions— In medically refractory patients with high-grade intracranial atherosclerotic stenoses, a new treatment paradigm involving predilation with an undersized Gateway percutaneous transluminal angioplasty balloon catheter and placement of a self-expanding Wingspan stent system appears to be safe, may facilitate remodeling, and may contribute to favorable angiographic outcomes.

Mechanical Thrombolysis in Acute Ischemic Stroke With Endovascular Photoacoustic Recanalization

Background and Purpose— We present the results of endovascular photoacoustic recanalization (EPAR) treatment for acute ischemic stroke from the Safety and Performance Study at 6 centers in Europe and North America. The objectives of mechanical thrombolysis are rapid vessel recanalization and minimal use of chemical thrombolysis. Methods— This study was a prospective, nonrandomized study. The National Institutes of Health Stroke Scale (NIHSS) score and the modified Rankin Scale (mRS) score were recorded before treatment. The presence of recanalization was assessed by angiography. To measure outcome, follow-up examinations were performed at 24 hours, 7 days, and 30 days after stroke onset. Results— Thirty-four patients (median NIHSS 19) were enrolled. Ten patients had internal carotid artery occlusion, 12 patients had middle cerebral artery occlusion, 11 patients had vertebrobasilar occlusion, and 1 patient had posterior cerebral artery occlusion. The overall recanalization rate was 41.1% (14/34). Complete EPAR treatment was possible in 18 patients (median NIHSS 18), with vessel recanalization in 11 patients (61.1%) after EPAR. The average lasing time was 9.65 minutes. Incomplete EPAR treatment (16/34, median NIHSS 19) was defined as intention to treat with EPAR and that the EPAR microcatheter entered the patient. Additional treatment with intraarterial application of rTPA occurred in 13 patients. An adverse event associated with use of the device occurred in 1 patient. Symptomatic hemorrhages occurred in 2 patients (5.9%). The mortality rate was 38.2%. Conclusions— This study demonstrates the safety and technical feasibility of EPAR. This new technique may provide another treatment option in the therapeutic armamentarium for patients with acute ischemic stroke.

Nuclear Factor I X Deficiency Causes Brain Malformation and Severe Skeletal Defects

ABSTRACT The transcription factor family of nuclear factor I (NFI) proteins is encoded by four closely related genes: Nfia, Nfib, Nfic, and Nfix. A potential role for NFI proteins in regulating developmental processes has been implicated by their specific expression pattern during embryonic development and by analysis of NFI-deficient mice. It was shown that loss of NFIA results in hydrocephalus and agenesis of the corpus callosum and that NFIB deficiency leads to neurological defects and to severe lung hypoplasia, whereas Nfic knockout mice exhibit specific tooth defects. Here we report the knockout analysis of the fourth and last member of this gene family, Nfix. Loss of NFIX is postnatally lethal and leads to hydrocephalus and to a partial agenesis of the corpus callosum. Furthermore, NFIX-deficient mice develop a deformation of the spine, which is due to a delay in ossification of vertebral bodies and a progressive degeneration of intervertebral disks. Impaired endochondral ossification and decreased mineralization were also observed in femoral sections of Nfix−/− mice. Consistent with the defects in bone ossification we could show that the expression level of tetranectin, a plasminogen-binding protein involved in mineralization, is specifically downregulated in bones of NFIX-deficient mice.

Clinical Features of Paraganglioma Syndromes

Head and neck paragangliomas (HNPs) and pheochromocytomas are rare tumors. Sporadic and hereditary forms are recognized. Four different paraganglioma syndromes (PGLs 1-4) have been described: PGL 1 is associated with mutations of the succinate dehydrogenase (SDH) subunit D (SDHD) gene; PGL 3 is caused by SDHC gene mutations; PGL 4 is caused by SDHB gene mutations; the susceptibility gene for PGL 2 is unknown. The objective of this study is to review distinct clinical features of the different PGLs. An international registry for HNPs was founded in Freiburg, Germany, in 2000. The data presented in this article have been acquired from registered HNP patients who have been screened for mutations of the genes SDHB, SDHC, and SDHD. Approximately 30% of apparent sporadic HNPs are caused by a germline mutation in one of these genes. Patients with PGL 1 or 4 have a very high lifetime risk of developing HNPs as well as thoracic and abdominal pheochromocytomas. Compared with sporadic HNPs, tumors developing in SDHB, SDHC, and SDHD mutation carriers arise at a significantly younger age. The SDHB mutations are associated with a high percentage of malignant paraganglionic tumors. We recommend molecular genetic screening of all HNP patients for SDHB, SDHC, and SDHD gene mutations. Mutation carriers must be screened for paraganglial tumors in the head, neck, thorax, and abdomen. Appropriately timed surgical intervention will minimize disease-specific morbidity and mortality. Lifelong follow-up is mandatory.

Neurosurgical Interventions in Children with Maroteaux-Lamy Syndrome

This paper reports the case of a 14-year-old child with Maroteaux-Lamy syndrome (mucopolysaccharidosis type 6) who was treated consecutively for compressive damage of the optic nerves, hydrocephalus communicans and progressive spastic tetraparesis within 2 years. The clinical course of the patient is presented and the pathophysiologic mechanisms of disease progression in patients with Maroteux-Lamy syndrome are discussed and reviewed.

MRI of active otosclerosis

Abstract Our aim was to determine whether MRI reliably shows pathology in patients with active otosclerosis (otospongiosis). We studied five patients with clinical and audiometric signs of this disorder and positive findings on high-resolution CT and tympanocochlear scintigraphy. Contrast enhancement of otospongiotic lesions was found in all affected ears, and could be topographically related to demineralised otospongiotic foci on CT. In lesions in the lateral wall of the labyrinth MRI sometimes showed the pathology better than CT, where partial-volume effects could be troublesome.

Selective involvement of the globus pallidus and dentate nucleus in succinic semialdehyde dehydrogenase deficiency

Abstract. MRI findings in a 12-year-old boy with succinic semialdehyde dehydrogenase (SSADH) deficiency are described. SSADH deficiency is a rare neurometabolic disorder of GABA catabolism. The clinical diagnosis is difficult and the disease is underdiagnosed. MRI showed an unusual pattern with hyperintense signal in the globus pallidus and cerebellar dentate nucleus in T2-weighted images. The remaining basal ganglia and white matter were normal. This is the second report showing this particular pattern of pallidal-dentate nucleus involvement, which might be suggestive for SSADH deficiency.

POLY-LACTIC-ACID COATING FOR ENDOVASCULAR STENTS : PRELIMINARY RESULTS IN CANINE EXPERIMENTAL ARTERIOVENOUS FISTULAE

RATIONALE AND OBJECTIVES The authors evaluate polylactic-acid (PLA) as a coating of vascular endoprostheses in the treatment of experimental arteriovenous fistulae (AVF) in a canine model. METHODS Bilateral carotid external jugular AVF were created in five adult dogs. Seven PLA-coated nitinol stents were placed using a transfemoral approach to cover five AVF. Contralateral controls remained untreated. Angiography was performed immediately after stent placement and at weeks 1 and 3, as well as at months 3, 6, and 9. All grafts were removed and underwent histologic examination. RESULTS In two cases, the occlusion of the AVF was successful, but misplacement of stents occurred in three cases, which showed occlusion of the parent vessel between week 1 and month 3. One thrombembolic stent occlusion was evident during angiographic control. One vessel occlusion was disclosed distal to the stented arterial segment. Histologic examination revealed a mild inflammatory reaction with the presence of macrophages. However, there was no foreign-body reaction of fragmentation of the vessel wall. CONCLUSIONS Histologic examination revealed good biocompatibility of PLA, which is a well-known biodegradable material. Elastic mismatch of the nonelastic coating and the self-expandable nitinol stent led to misplacement, whereas vessel occlusion was probably due to PLA filaments fraying into the vessel lumen. Using a different textile structure, PLA might be a material suitable for coated stents.

Characterization of hemangioblastomas of spinal nerves

OBJECTIVE:Hemangioblastoma is classified as a benign tumor of the central nervous system. Peripheral nervous system hemangioblastomas to date have been described only in a few case reports. Experience in treating patients with these rare lesions, which harbor diagnostic and therapeutic pitfalls, is limited. METHODS:To characterize these lesions better, we reviewed our hemangioblastoma database for patients who underwent surgery for extradural hemangioblastoma of the spinal nerve. RESULTS:Between 1983 and 2003, six patients underwent surgery for spinal nerve hemangioblastomas at our institution. These tumors occurred in 2% of all patients with hemangioblastomas of the central nervous system, or 6% of all patients with spinal hemangioblastomas. The occurrence did not differ in von Hippel-Lindau disease cases versus sporadic cases. Radiographically, the tumors easily could be mistaken for schwannomas or metastases; however, they did have some typical features. If a hemangioblastoma was not suspected primarily, profuse bleeding could complicate surgery. Most of the tumors arose from the dorsal sensory fascicles. The vascular supply was from extradural circulation. In general, the surgical outcome of these lesions was good, and permanent neurological deficit was rare. However, local recurrence was observed in three of six patients. CONCLUSION:These tumors harbor diagnostic and therapeutic pitfalls. In general, the tumors are surgically more challenging, and clinically significant bleeding as well as local tumor recurrence is more common than in intradural hemangioblastomas, mostly because of the frequency of incorrect initial radiographic diagnosis. We suggest that because of the surgical consequences, hemangioblastoma should always be considered to be an important radiological differential diagnosis for nerve sheath tumors. Angiography can bring clarification to ambiguous cases.

Benefits and limitations of image guidance in the surgical treatment of intracranial dural arteriovenous fistulas.

SummaryBackground. Despite major advances in endovascular embolization techniques, microsurgical resection remains a reliable and effective treatment modality for dural arteriovenous fistulas (DAVF). However, intraoperative detection of these lesions and identification of feeding arteries and draining veins can be challenging. In a series of 6 patients who were not candidates for definitive treatment by endovascular embolization we evaluated the benefits and limitations of computer-assisted image guidance for surgical ablation of DAVF. Methods. Of the 6 patients, 5 presented with haemorrhage and one with seizures. Diagnosis of DAVF was made by conventional angiography and dynamic contrast enhanced MR angiography (CE-MRA). All patients were surgically treated with the assistance of a 3D high resolution T1-weighted MR data set and time-of-flight MR angiography (MRA) obtained for neuronavigation. Registration was based on cranial fiducials and image-guided surgery was performed with the navigation system. Findings. Four of the 6 patients suffered from DAVF draining into the superior sagittal sinus, one fistula drained into paracavernous veins adjacent to the superior petrosal sinus and one patient had a pial fistula draining in the straight sinus. DAVF diagnosed with conventional angiography could be located on CE-MRA and MRA prior to surgery. MRI and MRA images were combined on the neuronavigation workstation and DAVF were located intraoperatively by using a tracking device. In 4 out of 6 cases neuronavigation was used for direct intraoperative identification of DAVF. Brain shift prevented direct tracking of pathological vessels in the other 2 cases, where navigation could only be used to assist craniotomy. Microsurgical dissection and coagulation of the fistulas led to complete cure in all patients as confirmed by angiography. Conclusions. Neuronavigation may be used as an additional tool for microsurgical treatment of DAVF. However, in this small series of 6 cases, surgical procedures have not been substantially altered by the use of the neuronavigation system. Image guidance has been beneficial for the location of small, superficially located DAVF, whereas a navigated approach to deep-seated lesions was less accurate due to the familiar problem of brain shift and brain retraction during surgery.