Robert L. Galloway - US grants

The objective of this project is to test and refine a device to assist a surgeon in locating a target of interest as defined from pre-operative medical images. The method, an outgrowth of stereotactic surgery, combines recent advances in medical imaging, high precision position sensing, robotics and computer technology to provide the surgeon with an interactive display of the present position of a surgical instrument on the pre- operative images. Once the device has been calibrated and its accuracy defined and validated, the device can be used to: 1) guide the surgeon directly to the target point, minimizing the size of the total resection, 2) guide the surgeon to objects, such as tumor margins, which may be defined on CT or MR images but be visually indistinguishable from normal tissue, 3) guide the placement of brachytherapy radiation sources for optimum dose distribution, 4) steer laser resection and 5), guide electrode and biosensor placement. If successful, the arm should incorporate the stereotactic advantage of accurate registration of image and physical space without the requirements of present frame-based systems.

9703714 Galloway The objective of this research is the development of a process for merging Interactive, Image-Guided Surgery (IIGS) with Minimally Invasive Surgery (MIS). The IIGS is the display of present surgical position and trajectory on preoperatively obtained tomographic images. The MIS is a technique by which surgical exposures and damage to healthy tissues are reduced by the use of endoscopes to allow surgical visualization through small openings in the skin. These two techniques are complementary, MIS presents high magnification, real-time imaging at the cost of a small depth of field and surface-only imaging, while IIGS provides a wide field of view with three-dimensional information but uses images which do not reflect anatomic changes since their acquisition. By using the proposed merging process, both the tomographic information and the video input will appear on the same computer screen allowing the surgeon to use each imaging modality for its strength and mitigating the disadvantages of each. The combination of these techniques would be accomplished in three steps: (1) the creation of a device which allows the determination of the visualization geometry of the endoscope and the tracking of that geometry in three-dimensional physical space, (2) the design, programming and testing of software to allow the display of high throughout image formation, and (3) the development of alternatives to conventional IIGS display modes to allow flexibility depending on the nature of the surgical situation. This process could result in improved outcomes as measured by more complete resections and reduced damage to healthy tissue. ***

DESCRIPTION (provided by applicant): Minimally-invasive endoscopic techniques are the standard of care in many specialties. Surgical endoscopy has allowed small incisions to replace large radical surgical approaches, resulting in improved outcomes and reduced operating times. Image guidance, the next technological advancement, provides intra- operative confirmation of surgical anatomy, and also reduces operative time and cost. Image guidance improves surgical performance by precisely mapping surgical anatomy to pre-operative images. Real time overlay of surgical tools onto pre-operative images allows for improved targeting of surgical coordinates. The anatomic constraints of many body cavities, particularly those filled with fat, have limited application of these technologies. Image guidance will facilitate the solution of minimally-invasive flexible endoscopy. Real time display of surgical position is accomplished by measuring and then registering, image space and surgical space. With image guidance we will be able to safely reach remote surgical targets. Traditional image guidance maps rigid tools onto pre-operative images. Many body areas are not well accessed with rigid instruments but could be reached with a flexible endoscope. A tracked flexible endoscope would benefit a wide spectrum of medical and surgical disciplines. An endoscope shows a clear, but myopic, image of the area immediately in front of the camera - it gives no information regarding relative spatial or anatomic relationships. We plan to solve the myopia problem and provide the needed information of where the endoscope is and what it is looking at. This technology will allow for direct treatment of remote targets, best reached with a flexible endoscope. We propose a minimally invasive, image guided endoscopic approach to a surgical target in a fat filled cavity. In order to determine the potential of translating this technology for patient care, we will 1) determine the Target Registration Error and 2) compare performance of image guided endoscopy to non-image guided endoscopy in a surgical model of orbital endoscopy (outcome measures include total time of surgery, time to the optic nerve target, and accuracy of target localization). With the experiments proposed in this study, we will allow for imaged guided flexible endoscopic treatments. PUBLIC HEALTH RELEVANCE: The proposed image-guided flexible endoscope will allow for minimally invasive surgical and medical interventions. Development of this new technology is particularly relevant to the emerging concepts of smaller surgical wounds with less disruption of native anatomy. Access to remote locations will allow for a treatment paradigm shift in many medical disciplines.