03/2 Advanced integration of computer aided planning and navigation in cranio-maxillofacial surgery

		Cephalometric feedback during planning of bimaxillary osteotomy. Schematic view showing how a Direct Acoustic Cochlear Stimulator (DACS) system is implanted.

Dedicated computer assistance is realised for a variety of CMF applications, not only covering planning and navigation support for bony manipulation, i.e., osteotomies and fragment relocation, but also taking into consideration the influence that these procedures have on the soft tissue situation. Rapid prototyping techniques as a possibility to allow for hands-on preoperative planning will be analysed.

Currently we are focusing on the surgical treatment of patients with moderate to severe mixed hearing loss (MHL), which is a difficult task. The operative field has limited viewing angles and the implantation can only be undertaken by an experienced otological surgeon. Thus, a wide surgical exposure is required to identify anatomic landmarks to avoid injury to any critical structures. Even though, protection of adjacent facial nerve in otologic surgery is still a constraint for the surgeon. In addition, human limitations in dexterity and tactile sensitivity further complicate and constrain such a microsurgical procedure.

This subproject aims for developing a computer guided, mechatronic assisted navigation system for implantation of hearing aid systems. Natural human limitations in both dexterity and tactile sensitivity will be alleviated by using robotic devices, which offer the possibility of extending human performance to permit fine manipulation tasks that are normally considered difficult or impossible. The constrained operative field with limited viewing angles will be virtually enlarged by using augmented reality visualisation provided by computer navigation. Protection of facial nerve will be improved by constraining the movement of robotic device to a safe zone, which could be a drilling path or an operational region that is well prepared on the volumetric images of the patient by the surgeon pre-operatively and intra-operatively transformed to the patient frame of reference through a registration process.