Article
Magnetic guided neuronavigation in transsphenoidal surgery of sellar and parasellar tumors
Magnetisch geführte Neuronavigation in der transsphenoidalen Chirurgie sellärer und parasellärer Tumore
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Authors
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C. Schichor
- Neurochirurgische Klinik der Ludwig-Maximilians-Universität München, Klinikum Großhadern, München
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J. Witte
- Brainlab AG Heimstetten
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K. Schöller
- Neurochirurgische Klinik der Ludwig-Maximilians-Universität München, Klinikum Großhadern, München
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P. Tanner
- Neurochirurgische Klinik der Ludwig-Maximilians-Universität München, Klinikum Großhadern, München
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R. Goldbrunner
- Neurochirurgische Klinik der Ludwig-Maximilians-Universität München, Klinikum Großhadern, München
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J.-C. Tonn
- Neurochirurgische Klinik der Ludwig-Maximilians-Universität München, Klinikum Großhadern, München
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E. Uhl.
- Neurochirurgische Klinik der Ludwig-Maximilians-Universität München, Klinikum Großhadern, München
| Published: | May 4, 2005 |
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Outline
Text
Objective
Complications of transsphenoidal surgery include anterior pituitary insufficiency, diabetes insipidus and cerebrospinal fluid fistulas. Rarely, injuries to carotid artery, sinus confluens or hypothalamic structures are reported. Integration of neuronavigation in transsphenoidal surgery should avoid misdirection. Disadvantages of current optical tracking systems are the so-called „line-of-sight“ problem, since optical sensors can get hidden by drapes or by the surgical microscope and rigid pin-fixation of the patient`s head. Aim of this study was to evaluate the potential to avoid these problems and the accuracy of a newly developed magnetic tracking system. The pointer of the system is a flexible stylet whose distal tip is tracked. Rigid pin-fixation of the patients head was unnecessary as an magnetic reference-sensor was fixed on the patient´s head.
Methods
The sensor of the flexible stylet, placed at the tip of the instrument, was tracked by a 3D magnetic system (based on a Kolibri® (Brainlab AG, Munich) Image Guidance System). The accuracy of the magnetic tracking system was controlled by bony landmarks that could be easily recognized visually or radiologically. 15 patients with tumours of the pituitary gland were included. Possible intraoperative magnetic fields and metallic instruments were tested for their influence on the navigation system.
Results
In cadaver tests, the accuracy of the system was similar to optical tracking systems (which only track the proximal end of the probe). But tracking the sensor at the tip of the flexible instrument also enabled the system to guide anatomical points which would not have been assessed by rigid optical tracking systems. The influence of magnetic fields and metallic instruments in the operating theatre was low and could be easily avoided. In 12 patients with pituitary tumors the accuracy of the neuronavigation was estimated below 5mm. During the developmental phase of the system, in 3 patients accuracy was worse than 5mm. In all patients, whose heads were not fixed in a rigid mayfield pin fixation, accuracy of the registration was maintained.
Conclusions
Magnetic tracking of the tip of the stylet is a reliable method, applied during endonasal transsphenoidal surgery. The magnetic guided Neuronavigation is a valuable addition to the armamentarium of navigational systems existing so far.
