The Laryngoscope Lippincott Williams & Wilkins, Inc. © 2004 The American Laryngological, Rhinological and Otological Society, Inc. How I Do It A Targeted Problem and Its Solution Temporary Intermaxillary Fixation using Individualized Acrylic Splints Permits Image–Data-Based Surgery of the Lower Jaw and Oropharynx Ju ¨ rgen Hoffmann, MD, DMD, PhD; Dirk Troitzsch, MS; Carsten Westendorff, MD; Octavio Weinhold, DMD; Siegmar Reinert, MD, DMD, PhD Objectives/Hypothesis: Image– data-based surgical navigation is used as a helpful device in the operating room to localize critical structures with a high degree of accuracy. It also enables physicians to plan therapeutic performance. Because it relies on preoperatively ac- quired computed tomography (CT) or magnetic resonance imaging (MRI) data, there is restricted access for navigation of surgical instruments in areas that show motion uncorrelated with radio- logic data. Thus, in the case of moveable struc- tures, for example the lower jaw, navigational procedures could not yet be applied. Study De- sign: We introduce a new technique using individ- ualized intermaxillary splints that fix the mandi- ble in a reproducible aboccluded position at the time of image-data acquisition and surgery. Meth- ods: Different manufacturing processes were in- vestigated. The feasibility of uni- and bilateral intermaxillary splints was studied under clinical conditions in four patients during different pro- cedures in the mandibular and oropharyngeal re- gions. Results: The manufacturing of the splints showed was easily performed in a short time. With bilateral fixation, there was a high anatomic tar- get precision of 1.6 to 2.3 mm. Conclusions: The use of bilateral intermaxillary splints that fix the patient’s mandible in a reproducible aboccluded position permits an image–data-based navigated surgical approach to the oropharyngeal and man- dibular regions. Key Words: Navigation, image guided surgery, computer assisted surgery, CAS. Laryngoscope, 114:1506 –1509, 2004 INTRODUCTION In modern surgery, image– data-based navigation be- comes increasingly important, particularly with regard to minimally invasive interventions. 1 Providing a continu- ally updated three-dimensional (3D) orientation of surgi- cal instruments in anatomic areas that are not easily accessible by direct visual or endoscopic–inspection- navigated surgery is useful in localizing critical structures with a high degree of accuracy. Invented for the field of stereotactical interventions in neurosurgery, this naviga- tion has recently been introduced to other specialities and is about to be established in head and neck surgery. 2–5 In craniofacial surgery, computer assistance has shown to be helpful (e.g., in the removal of foreign bodies, insertion of dental implants in anatomically complex operation sites, and resection of tumors). 6–9 Furthermore, there is appli- cation in the field of craniofacial malformations and para- nasal sinus surgery. 5,10 Currently, the use of navigation is restricted to ana- tomic regions and structures that do not show motion uncorrelated with preoperatively attained magnetic reso- nance imaging (MRI) or computed tomography (CT) scan data. Referencing of statically indeterminate parts of the body such as the mandible or the oropharyngeal region remains impossible. We introduce a new technique that uses individual- ized intermaxillary splints that fix the mandible in a re- producible aboccluded and adynamic position during image-data acquisition and surgery, permitting a navi- gated surgical approach to the oropharyngeal and man- From the Department of Oral and Maxillofacial Plastic Surgery, Tu ¨ bingen University Hospital, Tu ¨ bingen, Germany. Editor’s Note: This Manuscript was accepted for publication Febru- ary 3, 2004. Send Correspondence to Dr. Ju ¨ rgen Hoffmann, Department of Oral and Maxillofacial Plastic Surgery, Tu ¨ bingen University Hospital, Osianderstrasse 2– 8, 72076 Tu ¨ bingen, Germany. E-mail: juergen.hoffmann@uni-tuebingen.de Laryngoscope 114: August 2004 Hoffmann et al.: Temporary Intermaxillary Fixation 1506