OBJECTIVE: Endovascular treatment of intracranial aneurysms employing endosaccular coiling can be associated with aneurysm perforation, coil herniation or incomplete obliteration fueling the interest to investigate novel endovascular techniques. We aimed to test a novel embolization material in experimental aneurysms in vitro and in vivo whereby intra-arterially administered magnetic microparticles (MMPs) are navigated into the lumen of vascular aneurysms with assistance from an external magnetic field.
METHODS: MMPs are core-shell particles suspended in saline that have a shell made of a polymeric material and a core made of magnetite (Fe3O4). They have a diameter of 1.4 μm. During MMP administration via a microcatheter, a magnetic field was applied externally to direct the particles with the use of a solid-state neodymium magnet. Experiments were performed in a perfused silicone vessel and aneurysm model to evaluate application techniques and fluid dynamics and in the elastase aneurysm model in rabbits to evaluate in vivo compatibility, including multiorgan histological examinations and long-term stability of aneurysm embolization.
RESULTS: It was possible to steer and hold the MMPs within the aneurismal cavity where they occluded the lumen progressively. After removal of the external magnetic field, the results remained stable in vivo for the remainder of the observational period (30 minutes); after a 12-week observational period, recanalization of the aneurysm occurred.
CONCLUSION: MMPs can be magnetically directed into aneurysms, allowing short-term obliteration. Although the method has yet to show reliable long-term stability, these experiments provide proof of concept, encouraging further investigation of intravascular magnetic compounds.
*Department of Neuroradiology, University Hospital Aachen, Aachen, Germany; ‡Department of Neurology and Clinical Neurophysiology, Campus Benjamin Franklin, Charité-University Medicine Berlin, Berlin, Germany; §Neurosurgical Unit, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom; ¶Department of Radiology and Interventional Radiology, Municipal Hospital of Fulda, Fulda, Germany; ‖Clinic for Neurosurgery, University Hospital Aachen, Aachen, Germany; #Department of Neuropathology, University Hospital Aachen, Aachen, Germany; **Spiegelberg Gmbh & Co. KG, Hamburg, Germany; ‡‡Division of Neuroradiology, Department of Medical Imaging, University of Toronto, Toronto Western Hospital, Toronto, Ontario, Canada
Received, March 3, 2010.
Accepted, October 1, 2010.
Correspondence: Peter J. Kirkpatrick, FRCS (SN), FMedSci, Consultant Neurosurgeon, Box 167, Block A, Level 4, Department of Neurosurgery, Addenbrooke's Hospital, Cambridge, CB2 2QQ, UK. E-mail: firstname.lastname@example.org