Lesions of the lateral skull base in the petrous apex present unique surgical challenges because of the proximity of critical structures, including the inner ear, carotid artery, jugular bulb, facial nerve, lower cranial nerves, dura and brain. Currently, there are few appropriate surgical devices that can reach and remove these lesions, each with their own disadvantages. Here we investigate the feasibility of a dexterous continuum manipulator (DCM) capable of C-& S-shaped bends enabling dissection with remote center of motion (RCM) deep to the intact inner ear. A dedicated borescope channel provides the necessary visualization, while a flexible ring curette pre-shaped with a nitinol strip is designed to work through the instrument lumen for curettage of a cystic lesion. The kinematics of the DCM with the ring curette subject to an RCM constraint are investigated to explore the boundaries of a typical cyst cavity. Experiments in the planar phantom are carried out to validate feasibility, and results show that the proposed solution is practicable, accomplishing 80% and 83% removal of cysts for two kinds of boundaries.