An automated robotic approach with redundant navigation for minimal invasive extended transsphenoidal skull base surgery.

BACKGROUND: The aim of this work was to determine the feasibility of a robotic-assisted and fully automated approach to the sphenoid sinus. An image-guided robotic system was designed to address potential human errors in performing transsphenoidal sinus surgery by combining the reproducible accuracy of a robotic system with standard computer navigation. METHODS: A six-degrees of freedom robotic assistance system and an opto-electrical navigation system were combined for image-guided assistance with redundantly controlled robotics. Newly designed endoscopic instruments for robotic surgery have been developed and are described. Telemanipulatory, as well as fully automated procedures, were tested on cadaveric heads as part of a preclinical trial. RESULTS: A fully automated sphenoidotomy as well as a telemanipulatory sphenoidectomy were performed successfully on cadaveric heads. Intraoperative performance, accuracy assessment studies, as well as possible sources of stereotactic offsets are described. The mean measured robotic reproducibility accuracy was 0.056 mm (range: 0.02 - 0.14 mm) and the mean overall navigated robotic accuracy, including all transformation and registration errors was 1.53 mm (range: 1.13 - 1.89 mm) respectively. CONCLUSION: A system for robot-guided surgery in combination with redundant navigational control was developed. It allows highly accurate maneuvers, performed either in a telemanipulation mode as master-slave system or in a fully automated fashion. A sphenoidectomy on cadaveric heads was performed in both telemanipulation and fully automated modes. The overall intraoperative accuracy was in the range of the resolution of the CT images and stereotactic offsets were caused mainly due to deflections of the endoscopic operating instrument.

Increased safety in robotic paranasal sinus and skull base surgery with redundant navigation and automated registration.

We present an advanced version of our robotic setup for paranasal sinus surgery that was developed at the Department of Otorhinolaryngology, Head and Neck Surgery in Erlangen, Germany. The system was interconnected with a redundant navigation system for increasing intraoperative safety while performing telemanipulatory as well as fully automated maneuvers.In contrast to the previous "all in one" version, we built a modular three component setup. The basic feature of the computer navigation system is the "CAPPA ENT" station. The system references by automatically detecting a referencing frame mounted on a non-invasive upper jaw mouthpiece. Software components of both systems, navigation and robotics were combined on one user interface. Accuracy as well as clinical applicability studies were carried out. For better surveillance and increased safety, we decided to evaluate the robots reproducibility errors and overall stereotactic accuracy by means of redundant navigational control on a phantom model for paranasal sinus and skull base surgery. Multiple measurements from 14 CT-markers were taken representing different surgical approaches.A modular setup was designed and was deemed feasible in its size and weight dimensions as well as its maneuvrability for application in a routine operating room environment. The navigational feedback is integrated in real time in the robots user interface. In case of blocked visibility to the Dynamic Referencing Frame the robot powers down and activates the force torque sensor, thus softening all articulating joints. We found only adequate accuracies in pinpointing a specific CT-marker both in telemanipulatory and fully automated maneuvers. No significant offsets were observed evaluating accuracies for different surgical approaches.By using redundant navigation feedback, we were able to add another safety feature, the "loss of control" function, which shuts down any robotic action. However, no increase of the absolute accuracy was observed by adding this feature. We conclude that redundant navigational control does not make the robot more accurate, but it adds a potent safety feature to the system.