"The future of surgery is not about blood and guts; the future of surgery is about bits and bytes.”
/Dr. Richard Satava/

Friday, June 13, 2008

The Eye Robot

One of the advanced stage research projects in the lab is the Eye Robot. This robot has a similar structure than the Stead-Hand Robot, using an X-Y-Z linear base stage and a 3 DOF upper stage the realize the motion around a Remote Center Point (RCM). The main purpose is retina surgery. In many cases, physicians have to cannulate a microvessel (down to 100 um in size) to resolve a plaque or for other resons. This is very challenging with free hand due to the physiological tremor, even under the used microscope. With the robot, the surgeon first defines the RCM (the penetration point through the iris), and the robot will only allow motions where the needle does not leave the RCM, therefore does not damage the iris any further. The surgeon holds the needle mounted to the tip of the robot that uses cooperative control (based on force sensing) to follow the desired motions. The results can be seen through a binocular (3D) digital microscope.
At this stage of the research, several volunteers were involved to test their ability with and without the robot. We had to cannulate vessels of a chicken embrio (in a 6-8 days egg) that has a similar vessel structure than the human retina. The task was not easy at all, especially without the robot, as you had to keep the needle in the vessel for 60 s. (To monitor this, air was blown through the needle; if you did it wrong, bubbles apperaed all around the scene.) The experiment justified that people without any specific training were already capable of taking advantage of the robot. The next step is to do the same experiment with surgeons.

Wednesday, June 4, 2008

Diploma thesis

I have not posted in a long while, but I had a good reason for that: I was busy with my diploma thesis (for MS BME). It contains the up-to-date results of our research; therefore some readers might be interested in it. I made it available here.
The diploma thesis consists of five major parts. Chapter 1 gives an introduction to surgical robotics, reviewing the basic definitions and classification principles of the area. It features an extensive list of past and present neurosurgical systems based on my literature research. The most important systems are presented in detail. Chapter 2 introduces the JHU neurosurgical robot system I have been working on, giving a detailed description of the components, their capabilities and the software environment. Besides testing the existing system and learning about it, my task was from the very beginning to identify the main sources of errors in the setup, and individually find solutions fixing and improving them. Chapter 3 contains the list of errors and sources of problems identified allowing further development of the system. Major sources of errors are inspected individually, and measurements are documented. Chapter 4 contains the theoretical and numerical results of my project, introducing and evaluating the developed solutions for the improvement of robot calibration, control precision and adaptation to the changing operating room (OR) environment. Finally, the conclusion and future directions of the work can be found at the end. The research continues with the aim of producing a clinically validated surgical instrument with serious market potential.