Loosening of screws is rare- ↓ incidence of inflammatory complications More stable fixation than non locking plates (due to internal & external fixation) 4/21/2013 FAMUREWA & OLADEJO 39INSTRUMENTATION Reduction forceps Towel clip type Bone holding clamps Reduction/Compression forceps Plate holding forceps Screw driver ± holding sleeve (hexa, cruciform, phillip) Plate benders Bending irons Bending pliers (flat, pronged, side bender) Plate cutters Templates 4/21/2013 FAMUREWA & OLADEJO 41A typical system comprises of: Plates of different thicknesses, shapes and lengths Screws of different shaft diameters and lengths There are usually instruments to match different components of each system It is thus a precision driven art.
4/21/2013 FAMUREWA & OLADEJO 46Microplates – 1mm screws Miniplates May be regular or 3D Profiles usually 1-1.3mm 2.0mm used in mandible 1.3, 1.5,mm used in middle and upper third May accommodate locking mechanism in plates (small, medium, large, extra large profile mandibular plates) Come in different shapes and lengths May also come as meshes 4/21/2013 FAMUREWA & OLADEJO 47Compression plates They make use of bicortical screws Usually have at least a pair of eccentric holes The eccentric holes may be located on one side or both sides of the plate There are basically two types: Regular EDCP 4/21/2013 FAMUREWA & OLADEJO 48Reconstruction plates They are usually thicker for load bearing purposes May use locking or non-locking screws May have compression holes Can vary in thickness from 2mm and above Are used in defect bridging, comminuted fractures, weak bones (e.g. traditional techniques for the treatment of mandible fractures. 4/21/2013 FAMUREWA & OLADEJO 87CONCLUSION ORIF has become the gold standard of trauma care.
Gap healing seen in stable & quiet gap(Bone healing 2.
Secondary(indirect) bone healing- seen in non rigid internal fixation; mobile, wide gap btw # segments.
Limited vascular supply Insufficient bone quality or quality Has 1.5mm and 2.0mm systems May be from PGA, PDLL etc Manipulation is with heat (water bath or hot air) 4/21/2013 FAMUREWA & OLADEJO 56Surgical Approaches Use of existing laceration Intraoral Makes use of a vestibular incision With appropriate instruments and skill, can be used from symphysis to condyle. 4/21/2013 FAMUREWA & OLADEJO 88References Peterson’s Principles of Oral & Maxillofacial Surgery 2 nd Edition.
Use of transbuccal instruments, special contra-angled instruments and endoscope may be necessary in posterior regions. Treatment considerations for comminuted mandibular fractures. Atlas of Craniomaxillofacial Fixation Atlas of Craniomaxillofacial Osteosynthesis : Micoplates , Miniplates and Screws AO/ASIF Foundation online resources- AO Foundation website.4/21/2013 FAMUREWA & OLADEJO 10MATERIALS Reasons for metallic plates removal Patient’s wish Symptomatic implants Infection Foreign body response/reaction Wound dehiscence Implant extrusion/palpability/visibility Implant fracture Plate migration Thermal sensitivity Craniofacial growth disturbance in children Pain Radiological artefacts 4/21/2013 FAMUREWA & OLADEJO 11MATERIALS Metabolism of biodegradable implants: Hydrolysis→ short chained fragments→ phagocytosis(macrophages PMNs)→Lactate(monomers)→Pyruvate(gluconeogenesis &/or Kreb’s cycle)→ CO₂ H₂O Excretion- urine, faeces, expired air.Degradation time depends on - temperature, p H, presence of water, mechanical strain on implant, polymer configuration 4/21/2013 FAMUREWA & OLADEJO 13BIOMECHANICS Physiologically muscle functions produce tension @ the upper border & compression @ the lower border of the mandible.Gilmer(1881) - two posts adjacent to fracture line & lacing their ends with wire.Carl Hansmann(1852-1917) - pioneered plate fixation of fractures in 1886.This requires solid bony fragment on each side of # to bear some of the loads Examples of load-sharing fixation device- miniplate, lag screw and compression plates 4/21/2013 FAMUREWA & OLADEJO 31Compression vs Non compression plates Bone plates are either compression or non compression plates Compression is obtained by tightening screws down a ramped hole design. The compression holes are drilled eccentrically to allow for compression.Typically, the holes on either side of the fractures are designated for compression screw placement.Non rigid fixation- any technique of osteosynthesis that does not satisfy various definitions of rigid fixation.4/21/2013 FAMUREWA & OLADEJO 23Bone healing Primary(direct) bone healing In direct bone healing: No callus is formed Healing is by Haversian remodelling only- in contact healing(seen in rigid fixation).3D plates and plates with angles are frequently utilised Other plates in mandibular modules may be used 4/21/2013 FAMUREWA & OLADEJO 66RECONSTRUCTION Plates may be used to retain bone graft or flap Recon plates which may be locking or non locking are used Locking plates are preferred They require at least 3 screws on either side for adequate stability. Invited review: small versus large plate fixation of mandibular fractures. Condylar pieces are available for replacement 4/21/2013 FAMUREWA & OLADEJO 67Local Experience??? J Craniomaxillofac Trauma 1999;5(3):33-9; discussion 40.