Design and Development of a Robotic System for Pediatric Neurosurgery.

The advent of Minimal Invasive Surgery (MIS), a relatively modern method for performing surgeries, laid the grounds for robotic assistance in surgical procedures. Unlike conventional or open surgery, MIS uses long and slender surgical tools passed into the human body through small openings called incision points. The surgeons operate these tools from outside of the patient’s body by viewing the video feedback of an endoscopic camera inserted into the patient’s body. The most evident benefits of the MIS are reduced blood loss, lessened postoperative morbidity, shorter hospital stay, and slashed cost of healthcare. It is common to use MIS for various surgical procedures such as Laparoscopy, Nephrectomy, Orthopedics, Cardiology and Thoracic, and Neurosurgical procedures. In some procedures, such as Cholecystectomy, laparoscopy is considered the gold standard. The first robotic surgery was recorded more than three decades ago, and meanwhile, there was tremendous growth in surgical robotics in general. Surprisingly, neurosurgical robots developed at a slower pace. One reason behind this is the complex and delicate structure of the brain compared to other anatomical regions of human body which demands more sophisticated and miniaturized robotic tools. However, research on neurosurgical robots has gained pace during the last decade, and newly developed systems have started establishing their versatility, stability, dexterity, and potential to provide haptic feedback. Current neurosurgical robotic systems have contributed to enhancement of the quality of the surgery by minimizing registration errors and to acquiring spatial information. Nevertheless, all this advancement did not address the delicacy of neurosurgery in neonatal and infants. This thesis addresses the research gap mentioned above by developing a new neurosurgical robotic system for newborns and infants. Due to the absence of such a robotic system, surgeons have to perform these complex, delicate and time- consuming procedures manually. The challenges in performing these procedures include the requirement of multiple hands (to perform the surgery) in a confined space, inefficient sleeve holder, and the need for fine motor skills to perform delicate motions. To address these challenges, we have developed a robotic system that can assist surgeons in performing neonatal neurosurgeries. In this study, we presented a novel surgical robotic platform to assist surgeons in neuroendoscopy in infants. The design requirements of the robotic system were primarily obtained from observing the neuroendoscopic procedures. Subsequently, the acquired requirements were discussed with the team of neurosurgeons. Consequently, we agreed upon set of the requirements that the robotic system has to fulfil. The requirements were; establishing the remote center of motion (RCM) at the point of intervention and motorized manipulation (orientation, insertion, and inter-operative adjustment) of the end effector. The ranges of design requirement parameters were calculated using the real-life MRI of a baby. The MRI was later converted to a CAD model. The CAD model helped us in deriving the kinematic structure of the robotic system. We have realized that we needed a cartesian coordinate motion system to fix the RCM on a given point. However, a spherical motion system is required to cater to a (quasi) spherical workspace. We have used servo motors for the actuation of the joints and to have the required accuracy and repeatability. The actuated six degrees of freedom (DOFs) of the system replaced multiple hands in the workspace with a rigid support and a fine positioning system. The new robotic system can orient, insert, and hold the surgical sleeve at any point assigned by the surgeon. The robotic system has been designed to work seamlessly with intra-operative neuronavigation as required during the surgery. All system requirements have been tested through simulation and physical experiments. Kinematic analysis was performed to ensure that the robotic system meets the workspace and surgical tool’s reachability requirements. In addition, dynamic analysis was carried out to ensure the remote center of motion (RCM), decoupling of all the DOFs. These requirements were also validated through experiments with the new robotic system. After the developing of the robotic system, rigorous experiments were performed under the guidelines for determining the accuracy and repeatability of numerically controlled axes. The spherical motion system achieved the repeatability of 0.47, 0.141, and 405 for yaw, pitch, and translation respectively. In the future, the robotic system can be modified for haptic and force feedback. In addition, new control strategies could be developed to calculate and simulate the tool trajectory using the data from pre-operative MRI.