A Feasibility Study on the use of Concentric Tube Continuum Robots for Endonasal Skull Base Tumor Removal

INTRODUCTION We evaluate the ability of a robotic system with needlediameter, tentacle-like manipulators [1] to remove pituitary tumors endonasally. The robot consists of precurved superelastic tubes that can be axially rotated and telescopically extended to create controllable bending and elongation of the manipulator. Pituitary tumors account for 15-20% of all diagnosed primary brain tumors [2], and 1 in 5 people are likely to have one in their lifetime [2], with 1 in 120 of these growing large enough (>1cm) to require surgery [3]. In contrast to traditional transcranial and transfacial surgical approaches, the endonasal approach results in no disfigurement to the patient; rather than entering through large tunnels bored into the patient’s forehead or cheek, surgical instruments enter through the patient’s nostril(s). However, the endonasal procedure is only deployed in a small fraction of all pituitary tumor cases because of the challenge of manually manipulating multiple straight, rigid instruments through the constrained nostril entry port, while performing complex surgical motions at the skull base. A robotic approach to this procedure has the potential to reduce technical barriers and bring the benefits of endonasal surgery to many more patients. As has been demonstrated in other surgical applications, robots can do this by accurately manipulating small tools (e.g. [4]) and enhancing dexterity (e.g. [5]) in constrained spaces inside the patient. Systems have recently been introduced specifically for middle ear surgery [4] and throat surgery [5], among others. Endonasal surgery is a particularly challenging application for a robotic system, because of the small nostril access port and the dexterity required at the skull base. Some prior results exist on the use of robotic systems to aid in bone drilling to open access paths to the skull base (see e.g. [6]), and to assist in endoscope manipulation [7]. These are complementary to our approach [1], which is deployed after the surgical site is opened.