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59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

01. - 04.06.2008, Würzburg

Clinical use of an electromagnetic frameless stereotactic system for neuroendoscopic procedures

Meeting Abstract

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  • corresponding author L. Benvenuti - Department of Neurosurgery, Livorno City Hospital, Livorno, Italy
  • N. Desogus - Department of Neurosurgery, Livorno City Hospital, Livorno, Italy
  • R. Gagliardi - Department of Neurosurgery, Livorno City Hospital, Livorno, Italy

Deutsche Gesellschaft für Neurochirurgie. Società Italiana di Neurochirurgia. 59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch). Würzburg, 01.-04.06.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocDI.05.05

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Veröffentlicht: 30. Mai 2008

© 2008 Benvenuti et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen ( Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.



Objective: Frameless neuronavigation has been increasingly used in several neuroendoscopic procedures. Nevertheless the simultaneous use of neuronavigation and neuroendoscopy has been restricted as a result of the rigid cranial fixation and the other recognized limits of the optical tracking technology. In this study we assessed the clinical usefulness of an electromagnetic tracking system (Stealth Station® AxiEMTM, Medtronic, Louisville, CO) in a series of neuroendoscopic procedures.

Methods: The electromagnetic field referencing and tracking system was used in 34 consecutive patients who underwent neuroendoscopic procedures: 8 intraventricular and 26 transsphenoidal endoscopic procedures. Preoperative imaging consisted of computed tomography, magnetic resonance imaging or both. The system was evaluated with respect to its accuracy, reliability and usefulness. The accuracy was assessed by comparing the computer-estimated error with the real estimated error measured on the patient’s anatomy. Interference with standard operating room equipment was evaluated.

Results: Calculated accuracy (root mean square) was 1.3±0.7 mm. The accuracy was maintained throughout all the surgical procedures, using standard surgical tools. Interference from metal objects in the magnetic field was seen rarely, though all procedures were successfully carried out. The EM system improved the accuracy of the transsphenoidal endoscopic approach and resulted particularly useful in orientating surgeon during complex surgical procedures, with special reference to recurrent pituitary adenomas and abnormal anatomic situations. The EM tracking was helpful in entering small ventricles or in approaching the third ventricle when the foramen of Monro was narrow, while it was superfluous in standard ventricular anatomies.

The system provides a “pinless” solution for image-guided surgery and allows for truly dynamic and flexible patient positioning during the procedure; the “clear line of vision” between frame and cameras is no more required; the tracking device (EM stylet) is flexible and very thin, thus it does not conflict anytime with the endoscope and instruments can easily reach deep seated structures; the set up process is simple and non significantly time-consuming in the pre-operative phase.

Conclusions: The EM system overcomes the limits of the optical system by offering a comparable accuracy. In our experience this new technology enables easy and accurate performance of complex endoscopic procedures and expands the possibility of a simultaneous use of neuronavigation and neuroendoscopy.