Computer assisted positioning of the proximal segment after sagittal split osteotomy of the mandible: Preclinical investigation of a novel electromagnetic navigation system.
BACKGROUND
Modifications of the temporomandibular joint position after mandible osteotomy are reluctantly accepted in orthognathic surgery. To tackle this problem, we developed a new navigation system using miniaturized electromagnetic sensors. Our imageless navigation approach is therefore optimized to avoid complications of previously proposed optical approaches such as the interference with established surgical procedures and the line of sight problem.


METHODS
High oblique sagittal split osteotomies were performed on 6 plastic skull mandibles in a laboratory under conditions comparable to the operating theatre. The subsequent condyle reposition was guided by an intuitive user interface and performed by electromagnetic navigation. To prove the suitability and accuracy of this novel approach for condyle navigation, the positions of 3 titanium marker screws placed on each of the proximal segments were compared using pre- and postoperative Cone Beam Computed Tomography (CBCT) imaging.


RESULTS
Guided by the electromagnetic navigation system, positioning of the condyles was highly accurate in all dimensions. Translational discrepancies up to 0,65 mm and rotations up to 0,38° in mean could be measured postoperatively. There were no statistically significant differences between navigation results and CBCT measurements.


CONCLUSIONS
The intuitive user interface provides a simple way to precisely restore the initial position and orientation of the proximal mandibular segments. Our electromagnetic navigation system therefore yields a promising approach for orthognathic surgery applications.
Department of Medical Biometry and Informatics (Chair: Meinhard Kieser MSc, PhD), University Hospital Heidelberg, Germany. Electronic address: Igor.Nova@med.uni-heidelberg.de.
Igor
I
Nova
Department of Medical Biometry and Informatics (Chair: Meinhard Kieser MSc, PhD), University Hospital Heidelberg, Germany.
Sebastian
S
Kallus
Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
Moritz
M
Berger
Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
Oliver
O
Ristow
Department of Medical Biometry and Informatics (Chair: Meinhard Kieser MSc, PhD), University Hospital Heidelberg, Germany.
Urs
U
Eisenmann
Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
Christian
C
Freudlsperger
Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
Jürgen
J
Hoffmann
Department of Medical Biometry and Informatics (Chair: Meinhard Kieser MSc, PhD), University Hospital Heidelberg, Germany.
Hartmut
H
Dickhaus
D054893:Cone-Beam Computed Tomography; D055590:Electromagnetic Phenomena; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000601:surgery; D059229:Osteotomy, Sagittal Split Ramus / Q000295:instrumentation / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*
Computer assisted surgery; Electromagnetic tracking; Intraoperative navigation; Orthognathic surgery