There has been recent renewed interest in developing robotic technology to assist with transurethral surgery. Some of the earliest research on surgical robotics focused on TURP, with the goal to improve safety and accuracy of prostate resection [39]. HOLEP has recently emerged with excellent outcomes for even huge glands and has shown clinical advantage in a variety of RCTs [40–44]. HOLEP with its clinical advantages, limited dissemination, and steep learning curve might be an ideal procedure for improvements through computer-assisted surgery (CAS) (robotic) technology [45–49]. Thus, we sought to conceptualize, design, and develop a CAS system with the goal of increasing utilization of HOLEP [50].

The overall system design is based on the premise of concentric tubes, which utilize concentrically nested, precurved, elastic Nitinol tubes as the end-effectors. The basic robotic system consists of three main modules: the user interface, the transmission, and the endoscope (Fig. 34.3). The user interface consists of two handles, each with an embedded joystick and trigger. The user interface controls motors responsible for driving the concentric manipulators. Maneuvering the trigger and joysticks produces corresponding fine motions of the concentric tube manipulators. Gross movement of the endoscope is accomplished by using coordinated motions of both hands to manually manipulate the entire unit keeping the surgeon at the field and in control of the system. The device is suspended on a counterbalanced arm to assist the surgeon in supporting the weight of the robot and allow for ease of scope motions while using end-effector controls.

The current endoscope utilized is a continuous flow rigid nephroscope (Storz, Inc.), which was chosen as the offset lens design allows passage of the cannula tools through the working channel. The endoscope contains integrated light sources and optics, a 5 mm working channel through which two concentric tube manipulators are introduced. We have shown that our novel concentric tube endoscopic system is capable of performing complex movements of the end-effectors within a small working space in both phantom and ex-vivo experiments (Mitchell et al. J Endourology, [51]). Our initial work has shown that this robot has the ability to effectively perform tasks that could potentially decrease the technical challenges encountered during laser enucleation of the prostate.

We believe that this type of technology will be valuable for performing and disseminating HOLEP and could have potential to create novel endoscopic instrumentation.

“Steerable” needles come in a variety of designs and configurations and have the potential to alter the “linear path only” approach of current needles [51]. Webster et al. have described a steerable needle configuration based on nested, precurved concentric Nitinol tubes (Fig. 34.4) [52, 53]. As the number of tubes and complexities of the curves and path route increases, the kinematics and control necessitate the use of motorized drive and computer-assisted control (robotics) [54]. Nitinol, the same material used in cardiac stents, provides memory, strength, and flexibility. The computer-controlled robotic system coordinates the linear and rotational motion of all of the tubes and is able to steer the curved needle along specified paths. These needles can be made in a large range of diameters and curvatures. Potential roles for steerable needles in Urologic Surgery include biopsy and ablation delivery to previously unreachable or inaccessible areas combined with precise control and nonlinear path control [55, 56]. The significant customizability of this device is one of its strengths. These robots can carry a wide variety of surgical instruments through their central working channel. Ablation technology or lasers can be delivered through them and forceps or other small tools can be mounted to their tips. Burgner et al. recently described the use of multiple of these concentric tubes as the arms of a miniature tentacle-like surgical robotic device [56].

In Urology and a variety of other surgical fields, these robots offer many potential advantages. Current da Vinci instruments are limited in their size by the underlying wire and pulley architecture (Fig. 34.5). Concentric tube robots have now reached an exciting stage and we are currently using them in laboratory studies in the contexts of biopsy, thermal ablation, as a micro-laparoscopic robotics platform, and to create new types of trans-endoscopic robotic instrumentation.