Modification of Laser Alignment of Cranial X-Rays Intraoperatively

1. This presentation will probably involve audience discussion, which will create action items. Use PowerPoint to keep track of these action items during your presentation • In Slide Show, click on the right mouse button • Select “Meeting Minder” • Select the “Action Items” tab • Type in action items as they come up • Click OK to dismiss this box • This will automatically create an Action Item slide at the end of your presentation with your points entered. Modification of Laser Alignment of Cranial X-Rays Intraoperatively Pamela Tebebi Peter Konrad, MD, Ph.D (Advisor)

2. Functional Stereotactic Neurosurgery • Stereotaxy is technique used in surgery for directing an electrode to a specific locus in the brain • Intracerebral site is selected for destruction, stimulation, or physiological monitoring • Diseases associated: movement disorders (including Parkinson's Disease, tremor, and torticollis), epilepsy, pain and spasticity

3. Deep Brain Stimulation (DBS) for Movement Disorders • A surgical procedure whereby electrodes are permanently implanted in particular parts of the brain and continuous stimulation administered by a small electric unit (generator) that is implanted under the skin of the chest • Goals of DBS are to improve the control of movement on the side opposite the stimulator by modifying the brain cells in area of interest • Depending on the type of movement disorder, this may result in loss of tremor, loss of rigidity, loss of dyskinesia or dystonia • Risk of DBS • Most serious is bleeding into the brain causing headache, paralysis, coma, or death • Infection (10%) • Malfunction of stimulator • Movement of the electrode

4. Current Device for DBS • Many surgeon use CRW frame • Stereotactic frame is fixed in the skull and the stimulating electrode is driven through a burrhole • Can only be aligned once • Does not provide an accurate X-ray laser sighting alignment system for the comparison of the electrode stimulation site to the final site of the implant so as to verify that the implant is at the designated site Cosman-Roberts-Wells (CRW) apparatus; Photo from R. Galloway, R Maciunas. Stereotactic Neurosurery. Biomedical Engineering, Vol 18(3), 1990.

5. New Technology in DBS: mT Platform System • Developed by Frederick Haer & Co. (FHC), Inc (specialize in metal and glass microelectrode, needles and instrumentation for cellular research) • microTargeting Platform System requires no stereotactic frame or image guidance system • Vanderbilt is the first and only institution in the nation testing the device microTargeting (mT Platform) Platform System; Photo provided by FHC

6. New Technology in DBS: mT Platform System • mT Platform is design from importing CT and MR scans of the head into the mT Platform Planning and Design Software • Software allows neurosurgeon to design custom fixture based on the target, entry, references points, and etc. • Software virtually build the Platform in place on patient, including trajectory and target microTargeting (mT Platform) ; Photos provided by FHC

7. New Technology in DBS: mT Platform System • If virtual representation is satisfactory, data file is send to FHC for fabrication of Platform • No method for alignment • Does not provide an accurate X-ray laser sighting alignment system for the comparison of the electrode stimulation site to the final site of the implant so as to verify that the implant is at the designated site microTargeting (mT Platform) Platform System; Photo provided by FHC

8. Project Goal • Design an accurate sighting system by means of laser sighting alignment for intraoperative X-rays taken of brain stimulator implants

9. Proposed Alignment Device • Mount an aiming tube to a rectangular platform that is attached to a leg on mT Platform • Aiming tube is parallel to mid-sagittal plane • Center of tube is normal to mid-sagittal plane

10. Problem & Soloution to Proposed Alignment Device • PROBLEM: Too expensive for FHC to modify the software interface to allow attachment of alignment device to leg • Legs are based on a component that is loaded once and copied to other two position • Changing one leg would result in complete redesign • SOLUTION by FHC: Modify software to create a component for second hub

11. Alignment Device • Requires modification of the mT Platform • Requires modification of of the software model file written by FHC • Modification is less expensive • Both hubs point to the target site, and hub with tube is parallel to mid-sagittal plane Image provided by FHC

12. Alignment Device : components Image provided by FHC Aiming tube for X-ray with cross hair on both ends is attached to second hub Image provided by FHC mT Platform with second hub on the fixture

13. Alignment Device • Fixture has its mounting • surface surface parallel to the • mid-sagittal plane • Fixture has its center on a line • normal to the mid-sagittal • plane and extending from the • target point • Allows for a sagittal view • through the aiming tube Image provided by FHC

14. Alignment Device • When cross hairs at the ends of the tube are in line in the image, C-arm is aligned with predicted target point • Beam of the C-arm passes through the tube pointed at target point • All calculations and localization is done by mT Platform Planning and Design Software with out neurosurgeon having to align tube Image provided by FHC

15. Sample X-ray Image Stimulating electrode Implantationsite Stimulation site Stimulation site Implantation site

16. Tolerance • Target site area: 4X6mm • Allowable distance implant can be from site of stimulation: 0.5mm • If implant is placed more than 0.5mm from targeted stimulation result in no stimulation or undesirable side effects

17. Technology: Alignment Device • First of its kind; ~48 procedures/year • Vanderbilt University is the first institution to consider this new approach • Helpful tool for neurosurgeon; feel more comfortable about accurately placing the stimulating implants • X-ray is useful in lawsuits and beneficial to insurance company to verify correct placement of implant to stimulation site by neurosurgeon

18. Market Size • Neurosurgery: -tool for neurosurgeon • Medical and Research Institution: -prevent lawsuits -receive better insurance coverage

19. Device Status • Prototype model will be provided by FHC • Once completed the alignment device will be tested on patients here at Vanderbilt

20. Acknowledgements • Peter Konrad, MD, Ph.D (Vanderbilt University) • Ron Franklin, Senior Engineer (Frederick Haer & Co.) • Chris Koa, MD, Ph.D (Vanderbilt University) • Robert Galloway, Ph.D (Vanderbilt University) • John Song, MD (Vanderbilt University)

21. References • Surgery for Deep Brain Stimulation, Anderson MA, RN. Vanderbilt University Medical Center, Jan 2002. (pamphlet) • microTargeting Platform System incorporating STarFix guidance. User Manual A989-02, FHC, Inc, 2001. • Galloway RL, Cleary K, Peter T. Image Guided Procedures 2001 A Snapshot View. July 31 2001. • Galloway RL, Macinus RJ. Stereotactic Neurosurgery. Biomedical Engineering, Vol. 18(3), pp. 181-205, 1990. • Stereotactic Neurosurgery. Concepts in Neurosurgery. Heilbrum MP, Ed., Baltimore: William & Wilkins, Vol. 2., 1988. • Movement Disorder Surgery. Progress in Neurological Surgery. Lozano AM, Ed., New York: Karger, Vol. 15, 2000. • Shrivastava, RK, Germano IM. Deep Brain Stimulation for the Treatment of Parkinson’s Disease. Contemporary Neurosurgery, Vol.. 23(16), Aug 15, 2001.