A common-path optical coherence tomography distance-sensor based surface tracking and motion compensation hand-held microsurgical tool Kang Zhang a , Peter Gehlbach b , and Jin U. Kang a a Department of Electrical and Computer Engineering, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD, 21218 USA b Wilmer Eye Institute, The Johns Hopkins School of Medicine, 1550 Orleans Street, Baltimore, MD 21231 USA kzhang8@jhu.edu ABSTRACT Microsurgery requires constant attention to the involuntary motion due to physiological tremors. In this work, we demonstrated a simple and compact hand-held microsurgical tool capable of surface tracking and motion compensation based on common-path optical coherence tomography (CP-OCT) distance-sensor to improve the accuracy and safety of microsurgery. This tool is miniaturized into a 15mm-diameter plastic syringe and capable of surface tracking at less than 5 micrometer resolution. A phantom made with Intralipid layers is used to simulate a real tissue surface and a single-fiber integrated micro-dissector works as a surgical tip to perform tracking and accurate incision on the phantom surface. The micro-incision depth is evaluated after each operation through a fast 3D scanning by the Fourier domain OCT system. The results using the surface tracking and motion compensation tool show significant improvement compared to the results by free-hand. Keywords: Common-path optical coherence tomography, surface tracking, motion compensation, microsurgical tool 1. INTRODUCTION Microsurgery requires constant attention to and compensation for involuntary patient motion due to physiological processes such as breathing and cardiac pulsation, as well as the motion due to surgeon hand tremor. The resulting involuntary distance changes between the surgical tool and surgical tissue surface, although usually in the order of a few hundreds of micrometer at less than 5Hz, may cause serious error due to the scale of microsurgery. The “tool- tissue” relative motion is especially critical in the case of surface operations such as retina vitreous surgery and cerebral cortex neurosurgery where the fragile tissue’s axial involuntary motion is a primary concern that requires high dexterity and constant attention from experienced surgeons. Several hand tremor and motion compensation systems have been developed based on complex mechanical modules including robotics and electromagnetic motion sensors 1,2 , which basically uses accelerometers to sense the hand tremor and then uses micro actuators for active compensation. However, these systems lack direct sensing of the exact distance between surgical tip and target which eventually affects the quality of microsurgery. In this work, we have developed a simple and compact hand-held microsurgical tool capable of surface tracking and motion compensation based on common-path optical coherence tomography (CP-OCT) distance-sensor to improve the accuracy and safety of microsurgery. Our system uses a single fiber probe as a CP-OCT distance-sensor and a high-speed piezo-electric micro linear motor for the 1-D actuation. The distance between the tool tip and the surgical target surface is determined from the OCT signal by an automatic edge-searching algorithm. The micro linear motor is controlled by the computer according to the feedback from CP-OCT distance-sensor. In the current stage, our CP- OCT microsurgical tool is miniaturized into a 15mm-diameter plastic syringe and capable of surface tracking at less than 5 micrometer resolution. A phantom made with Intralipid layer is used to simulate a real tissue surface and a single-fiber integrated micro-dissector works as a surgical tip to perform tracking and accurate incision on the Optical Fibers, Sensors, and Devices for Biomedical Diagnostics and Treatment XI, edited by Israel Gannot, Proc. of SPIE Vol. 7894, 78940G · © 2011 SPIE · CCC code: 1605-7422/11/$18 · doi: 10.1117/12.874193 Proc. of SPIE Vol. 7894 78940G-1 Downloaded from SPIE Digital Library on 04 Mar 2011 to 128.220.160.6. Terms of Use: http://spiedl.org/terms