On the Feasibility of Orbital Apex Surgery with a Concentric Tube Robot

Objective: To assess the feasibility of robotic orbital apex surgery.

Introduction: Concentric tube robots are flexible, needle-diameter robots which have shown great promise for surgical application requiring dexterous tools to be passed into an anatomical space through a natural orifice or small incision.

A concentric tube robot consists of a set of multiple telescoping tubes, made of a highly flexible material such as Nitinol ([Fig. 1]). At least some of these tubes are pre-curved, so that when the tubes are rotated and translated relative to one another, this curvature causes bending and twisting of the collection of tubes. The result is a thin, flexible instrument capable of motion similar to that of a tentacle. Concentric tube robots are thus designed to reach around anatomical obstacles and provide the surgeon with better control over his tools in comparison with conventional rigid tools.

The orbit contains critical structures which the surgeon must be careful to avoid injuring during surgery, including the optic nerve, ophthalmic artery and ocular muscles. Resection of tumors in this space requires great dexterity and cooperation of multiple tools, making it a good candidate for the multi-arm robotic system.

Methods/Materials: We have developed a robotic system for trans-nasal endoscopic surgery which is capable of deploying three flexible arms through a nostril to access the entire skull base to perform cooperative tasks ([Fig. 2]). Arms can be equipped with a variety of tools, such as graspers, curettes, retractors, suction and irrigation, and may be exchanged quickly during a procedure. The surgeon operates this robot via a user interface, analogous to the way the da Vinci system is controlled.

Using a phantom skull and orbital system, a simulated tumor was successfully removed from the orbital apex ([Fig. 3]).

Conclusion: In this study, we have shown the feasibility of performing trans-nasal endoscopic orbital apex surgery of a simulated tumor using the concentric tube robotic system.

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No conflict of interest has been declared by the author(s).