Symposia

Symposium: Critical Evaluation of Rigid Fixation (cont’d)

Complications and Limitations Roger A. West, DMD, Seattle, WA

Rigid internal fixation in orthognathic surgery was introduced over a decade ago. However, limitations of the technique remain to be defined. Therefore, complications are inevitable. These will be discussed and solutions suggested. Limitations

Biomechanics Holding Power Biocompatability Passive Stabilization

Biological Considerations Bone Healing-“Primary” vs. “Gap Healing” Muscle Adaptation and Articular Cartilage

Complications Neurological

Marginal Mandibular Branch of Facial Nerve Inferior Alveolar Nerve

Temporomandibular Joint Proximal Fragment Control

Orientation of Proximal Fragment Reproducability of Centric Relation

Immobilization/Combined Rigid Internal Fixation and Intermaxillary Fixation

Meniscal Dysfunction Occlusion/Relapse

Maxilla Mandible

Infection Short term Long term

Current Research in Rigid Fixation Scott B. Boyd, DDS, PhD, Detroit, MI

This presentation will critically evaluate current basic research on rigid fixation related to bone healing and biomaterials and clinical investigations studying treat- ment outcome in the oral and maxillofacial surgery patient.

The technique of rigid fixation is currently applied to a variety of surgical problems in the oral and maxillofacial region including congenital, developmental and acquired defects. This presentation will critically evaluate current basic science literature related to bone healing and biomaterials and clinical investigations studying treat- ment outcome following the use of rigid fixation. Maxillofacial Trauma and Reconstructive Surgery

Materials and Instrumentation Treatment Outcome

Infection and Healing Temporomandibular Joint Function Malocclusion Mandibular Mobility and Muscle Function

Orthognathic and Craniofacial Surgery Instrumentation and Technique Treatment Outcome

Dentoskeletal Stability Subsequent Facial Growth Neurosensory Alterations Muscular Adaptation Temporomandibular Joint Function

References

Nishioka, G.J., Zysset, M.K., VanSickels, J.E.: Neurosensory distur- bance with rigid fixation of the bilateral sagittal split osteotomy. J Oral Maxillofac Surg 45:20-26, 1987

Raveh, J., Vuillemin, T., Ladrach, K., Roux, M., Sutter, F.: Plate osteosynthesis of 367 mandibular fractures. J Cranio-Max--Fat Surg 15~244-253, 1987

VanSickels, J.E., Larsen, A.J., Thrash, W.J.: Relapse after rigid fixation of mandibular avancement. J Oral Maxillofac Surg 44:698-702, 1986

Future Needs and Research Bruce N. Epker, DDS, MDS, PhD, Fort Worth, TX

When seeking solutions to existing shortcomings of our treatment methods, there is often cyclical enthusiasm that relates to untested new methods. Generally, with time and scientific evaluation of these “new methods”, they assume an appropriate position in our armamentarium. For this to occur it is required that we critically evaluate multiple aspects of the treatment methods and compare them to the accepted standards, This presentation will identify those areas of biological and applied clinical research which must be pursued in order for “rigid fixation” to take its rightful place in our armamentarium. Biological Research Needs

Are There Differences in How Bone Heals (primary vs. secondary) in Both the Maxilla and Mandibular with “Rigid Fixation” vs. Conventional Fixa- tion

What are the Biomechanical (loading strength) differ- ences at Various Time Intervals with “Rigid Fixation” vs. Conventional Fixation

How Long are the Screws and Plates Currently Uti- lized Actually Stable

Applied Clinical Research Needs Long Term Stability

Especially Related to Idiopathic Condylar Resorption Neurosensory Effects Condyle Positional Changes Adaptation Potential of TMJs Cost Variables to Patient Total Treatment Time

Post-operative Orthodontics These Data Can Lead to the Development of Specific

Relative Indications and Contraindications for “Rigid Fixation” versus Conventional Fixation and Direct Future Specific Arenas for Improve- ment

16 AAOMS l 1989