Application of electromagnetic technology to neuronavigation: a revolution in image-guided neurosurgery Technical note
ABSTRACT The authors investigated the practicality of electromagnetic neuronavigation in routine clinical use, and determined the applications for which it is at the advantage compared with other systems.
A magnetic field is generated encompassing the surgical volume. Devices containing miniaturized coils can be located within the field. The authors report on their experience in 150 cases performed with this technology.
Electromagnetic neuronavigation was performed in 44 endoscopies, 42 ventriculoperitoneal shunt insertions for slit ventricles, 21 routine shunt insertions, 6 complex shunt insertions, 14 external ventricular drain placements for traumatic brain injury, 5 awake craniotomies, 5 Ommaya reservoir placements, and for 13 other indications. Satisfactory positioning of ventricular catheters was achieved in all cases. No particular changes to the operating theater set-up were required, and no significant interference from ferromagnetic instruments was experienced. Neurophysiological monitoring was not affected, nor did it affect electromagnetic guidance.
Neuronavigation enables safe, accurate surgery, and may ultimately reduce complications and improve outcome. Electromagnetic technology allows frameless, pinless, image-guided surgery, and can be used in all procedures for which neuronavigation is appropriate. This technology was found to be particularly advantageous compared with other technologies in cases in which freedom of head movement was helpful. Electromagnetic neuronavigation was therefore well suited to CSF diversion procedures, awake craniotomies, and cases in which rigid head fixation was undesirable, such as in neonates. This technology extends the application of neuronavigation to routine shunt placement and ventricular catheter placement in patients with traumatic brain injury.
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ABSTRACT: Introduction. Posterior stabilization of the spine is a standard procedure in spinal surgery. In addition to the standard techniques, several new techniques have been developed. The objective of this cadaveric study was to examine the accuracy of a new electromagnetic navigation system for instrumentation of pedicle screws in the spine. Material and Method. Forty-eight pedicle screws were inserted in the thoracic spine of human cadavers using EMF navigation and instruments developed especially for electromagnetic navigation. The screw position was assessed postoperatively by a CT scan. Results. The screws were classified into 3 groups: grade 1 = ideal position; grade 2 = cortical penetration <2 mm; grade 3 = cortical penetration ≥2 mm. The initial evaluation of the system showed satisfied positioning for the thoracic spine; 37 of 48 screws (77.1%, 95% confidence interval [62.7%, 88%]) were classified as group 1 or 2. Discussion. The screw placement was satisfactory. The initial results show that there is room for improvement with some changes needed. The ease of use and short setup times should be pointed out. Instrumentation is achieved without restricting the operator's mobility during navigation. Conclusion. The results indicate a good placement technique for pedicle screws. Big advantages are the easy handling of the system.BioMed Research International 02/2015; 2015:183586. DOI:10.1155/2015/183586 · 2.71 Impact Factor
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ABSTRACT: Placement accuracy of ventriculostomy catheters is reported in a wide and variable range. Development of an efficient image-guidance system may improve physician performance and patient safety. We evaluate the prototype of Smart Stylet, a new electromagnetic image-guidance system for use during bedside ventriculostomy. Accuracy of the Smart Stylet system was assessed. System operators were evaluated for their ability to successfully target the ipsilateral frontal horn in a phantom model. Target registration error across 15 intracranial targets ranged from 1.3 to 4.6 mm (mean 3.1 mm). Using Smart Stylet guidance, a test operator successfully passed a ventriculostomy catheter to a shifted ipsilateral frontal horn 20/20 (100%) times from the frontal approach in a skull phantom. Without Smart Stylet guidance, the operator was successful 4/10 (40%) times from the right frontal approach and 6/10 (60%) times from the left frontal approach. In a separate experiment, resident operators were successful 2/4 (50%) times when targeting the shifted ipsilateral frontal horn with Smart Stylet guidance and 0/4 (0%) times without image guidance using a skull phantom. Smart Stylet may improve the ability to successfully target the ventricles during frontal ventriculostomy. © 2015 S. Karger AG, Basel.Stereotactic and Functional Neurosurgery 01/2015; 93(1):50-8. DOI:10.1159/000368906 · 1.48 Impact Factor
Article: Advanced Cranial Navigation[Show abstract] [Hide abstract]
ABSTRACT: BACKGROUND: Cranial surgical navigation is most commonly performed by registration with fiducial markers, optic tracking, and intermittent pointer-based application. OBJECTIVE: To assess the accuracy and applicability of an advanced cranial navigation setup. METHODS: Continuous electromagnetic instrument navigation was used in 136 neurosurgical cases with a standard navigation system. A phantom head in an intraoperative magnetic resonance imaging environment was used to compare the accuracy of the advanced and standard navigation setups. RESULTS: A navigated suction device was used in 71 cases of intracranial tumor surgery and 46 cases of endoscopic transsphenoidal surgery. The ventriculoscope was navigated in 6 cases and the stereotactic biopsy needle in 4 cases. Electromagnetic tracking was used for catheter placement in 9 cases. The learning curve comprised 6 of the 136 cases during the first month of application. No significant difference was observed at the intracranial target points between the standard navigation setup using optic tracking, fiducial marker registration, and pointer and the advanced navigation setup with electromagnetic tracking, surface-based registration, and navigation of a field-detecting stylet in a standard metal suction tube when performed outside the 5-G line of the 3.0-T intraoperative magnetic resonance imaging. CONCLUSION: Continuous instrument navigation is the prerequisite for seamless integration of navigation systems into the neurosurgical operating workflow. Our data confirm that the application of preoperative imaging, surface-merge registration, and continuous electromagnetic tip-tracked instrument navigation may provide such integration without a significant reduction in accuracy compared with standard navigation. ABBREVIATIONS: EM, electromagnetic iMRI, intraoperative magnetic resonance imaging RMSE, root mean square errorNeurosurgery 01/2013; 72:A43-A53. DOI:10.1227/NEU.0b013e3182750c03 · 3.03 Impact Factor