Novel Infrared Laser Tissue Fusion Laparoscopic Device Designs using Transparent Materials and Real-time Optical Feedback

Conventional suture ligation of vascular tissues during surgery is time consuming and skill intensive. Alternative techniques require hemostasis through mechanical clips or sutures, which leave foreign objects in the body and disrupt the procedure through the need to exchange instruments. In recent years, energy-based devices, such as ultrasonic (US) and radiofrequency (RF) electrosurgical based technologies, have been used for rapid and efficient blood vessel ligation. These devices expedite numerous labor-intensive surgical procedures (including lobectomy, nephrectomy, gastric bypass, splenectomy, thyroidectomy, hysterectomy, and colectomy). However, both US and RF devices have limitations, including potential for unacceptably large collateral thermal damage zones, with thermal spread averaging greater than 1 mm. This lack of specificity prevents the use of these devices for delicate surgical procedures performed in confined spaces (such as prostatectomy). These device jaws take a long time to cool down to normal body temperature between successive procedures and may also cause thermal damage to healthy tissue through unintended heat conduction from contact with the device jaws.
A novel alternative method using near-infrared (IR) lasers for vessel ligation may eliminate some of these limitations of conventional energy-based devices. In this study, two real-time optical feedback systems are explored along with transparent jaw designs for sealing and bisection of blood vessels. This thesis begins with an introduction and theory of tissue optics followed by the methods used for the study. It describes the use of tissue autofluorescence as a real time optical feedback system. After that, it details the testing and comparison, both experimentally and computationally, of quartz and sapphire optical materials. These materials are transparent and bio-compatible, intended for use in the optical chamber, a critical component of the laparoscopic device jaw. Then, it describes a simultaneous IR laser vessel sealing and bisection study using a quartz optical chamber suitable for integration into a laparoscopic device, and the feasibility of using the optical signal originating from the therapeutic laser and transmitted through the cut vessel, as a closed-loop, optical feedback system for immediately deactivating the IR laser upon successful vessel bisection. The following part discusses future work followed by the summarization of the main accomplishments of this thesis.