mandibular osteosynthesis

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INTRODUCTION Osteosynthesis (internal fixation) refers to placement of wires, screws, plates, rods, pins & other hardware directly to the bones to help stabilize a fracture. Mechanical devices- wires, rods, pins, screws and plates. 4/21/2013 FAMUREWA & OLADEJO 3


INDICATIONS Trauma- facial bone fracture Orthognathic surgery Reconstruction of craniofacial deformities Reconstruction of bony defects 2 ͦ to ablative tumour surgery. Augmentation of atrophic mandible in the elderly Iatrogenic -2 ͦ to anterior/lateral mandibulotomy 4/21/2013 FAMUREWA & OLADEJO 4


HISTORY Hippocrates(460-375 BC) - use of gold wires, linen thread & strips of leather for treating mandibular fractures. Gilmer(1881) - two posts adjacent to fracture line & lacing their ends with wire. Carl Hansmann(1852-1917) - pioneered plate fixation of fractures in 1886. William Halsted - improved on Hansmann’s work around 1893; subcutaneous screw implantation rather than percutaneous approach. 4/21/2013 FAMUREWA & OLADEJO 5


HISTORY Robert Danis(1880-1969) - He described the concept of primary fracture healing with peripheral callus formation. First to use compression plate in 1949; dubbed the father of modern osteosynthesis. AO/ASIF - was formed by General Surgeons, Orthopaedic Surgeons & scientists in 1958 4/21/2013 FAMUREWA & OLADEJO 6


HISTORY Luhr H.G - In 1968 used compression plates & self tapping screws for treating mandibular fractures Cock H.P.(1969) - used titanium plate for mandibular reconstruction after tumour ablation Michelet et al (1973) - advocated use of non compression plates & monocortical screws in mgt of mandibular fractures Maxime Champy & co(1976 vs 1978 )-Ideal line of osteosynthesis of mandible. Resorbable plates & screws introduced in 1990s. 4/21/2013 FAMUREWA & OLADEJO 7


MATERIALS Metallic and Resorbable (biodegradable) osteosynthetic devices. 1.Metallic Stainless steel Vitallium - trade name for alloy of chromium, cobalt & molybdenium Titanium 4/21/2013 FAMUREWA & OLADEJO 8


MATERIALS Stainless steel-has been abandoned due to corrosion & potential toxicity Vitallium- used by Luhr plate system Tensile strenght ↑ than titanium Biocompatible but does not osteointegrate 4/21/2013 FAMUREWA & OLADEJO 9


MATERIALS Titanium Ti-6Al-4V= 6% Aluminium+ 4% Vanadium Ti-6Al-7Nb= 6% Aluminium+ 7% Niobium Best corrosion resistance Biocompatible Osteointegrate In comparison with the other materials, offers least interference with MRI. 4/21/2013 FAMUREWA & OLADEJO 10


MATERIALS 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 11


MATERIALS Resorbable materials Polylactic acid(PLA) Polyglycolic acid(PGA) Polydioxanone (PDA) Copoloymers e.g PLLA+PDLA; PLLA + PGA(Lacto Sorb) 4/21/2013 FAMUREWA & OLADEJO 12


MATERIALS 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, pH, presence of water, mechanical strain on implant, polymer configuration 4/21/2013 FAMUREWA & OLADEJO 13


BIOMECHANICS Physiologically muscle functions produce tension @ the upper border & compression @ the lower border of the mandible. Torsional(twisting) force is generated in anterior mandible 4/21/2013 FAMUREWA & OLADEJO 14


BIOMECHANICS Tension zone- area on mandible where the muscle of mastication distract the fracture segments. Compression zone - area on mandible where the muscle of mastication appose the fracture segments Neutral(transition) zone- area of zero force btw compression & tension zones. 4/21/2013 FAMUREWA & OLADEJO 15




Biomechanics 4/21/2013 FAMUREWA & OLADEJO 17


Biomechanics Ideal osteosynthesis line of mandible(Champy’s) 4/21/2013 FAMUREWA & OLADEJO 18


Principles AO/ASIF Biomechanical principles of fracture mgt(1950s): Accurate anatomical reduction Atraumatic operative technique preserving bone & soft tissues vitality Rigid internal fixation that produces a mechanically stable skeletal unit Avoidance of soft tissue damage & “fracture dx” by allowing early, active pain-free mobilization of the skeletal unit 4/21/2013 FAMUREWA & OLADEJO 19


Principles AO/ASIF Biomechanical principles of fracture mgt In 1994, the 3 rd principle was changed to FUNCTIONALLY STABLE FIXATION. 4/21/2013 FAMUREWA & OLADEJO 20


CONCEPTS Rigid internal fixation & Non rigid fixation Load-bearing & load-sharing fixation Compression & Non compression plates osteosynthesis Locking & Non locking plate-screw system 4/21/2013 FAMUREWA & OLADEJO 21

Rigid internal fixation-definitions:

Rigid internal fixation-definitions Any form of bone fixation in which otherwise deforming biomechanical forces are either countered or used to advantage to stabilize the fracture fragments & to permit to permit loading of the bone so far as to permit active motion(Allgower & Spiegel 1979). 4/21/2013 FAMUREWA & OLADEJO 22

Rigid internal fixation-definition:

Rigid internal fixation-definition Any form of fixation applied directly to the bones which is strong enough to prevent interfragmentary motion across the fracture when actively using the skeletal structure(Ellis 1993). Non rigid fixation- any technique of osteosynthesis that does not satisfy various definitions of rigid fixation. 4/21/2013 FAMUREWA & OLADEJO 23

Rigid vs non rigid fixation:

Rigid vs non rigid fixation Examples of rigid fixation: Compression plates Two lag screws Reconstruction plates(with min of 3 screws across #). 4/21/2013 FAMUREWA & OLADEJO 24

Bone healing :

Bone 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). Gap healing seen in stable & quiet gap(>200µm) –bridged by lamellar bone followed by Haversian remodelling. 4/21/2013 FAMUREWA & OLADEJO 25

Contact(a) & Gap(b) healing:

Contact(a) & Gap(b) healing 4/21/2013 FAMUREWA & OLADEJO 26

Bone healing:

Bone healing 2.Secondary(indirect) bone healing- seen in non rigid internal fixation; mobile, wide gap btw # segments. There is formation of periosteal callus- to “immobilize” the segment Bone healing proceed from haematoma collection to differentiation of fibrous tissue to osseous tissue 4/21/2013 FAMUREWA & OLADEJO 27

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Load-bearing vs load-sharing fixation:

Load-bearing vs load-sharing fixation Load-bearing fixation is a device that is of a sufficient strength & rigidity that it can bear the entire load applied to the mandible during function. Indications for load-bearing fixation: Comminuted mandibular # Continuity defect of the mandible # of the atrophic edentulous mandible Reconstruction plate –example of device 4/21/2013 FAMUREWA & OLADEJO 29

Load-bearing fixation:

Load-bearing fixation 4/21/2013 FAMUREWA & OLADEJO 30

Load-sharing fixation:

Load-sharing fixation Load-sharing fixation is any fixation that is of insufficient stability to bear all of the functional loads applied across the # by the masticatory system. 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 31

Load-sharing fixation:

Load-sharing fixation 4/21/2013 FAMUREWA & OLADEJO 32

Compression vs Non compression plates:

Compression vs Non compression plates Bone plates are either compression or non compression plates Compression is obtained by tightening screws down a ramped hole design. This is the spherical gliding principle. 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. 4/21/2013 FAMUREWA & OLADEJO 33

compression plates:

compression plates 4/21/2013 FAMUREWA & OLADEJO 34

Compression vs Non compression plates:

Compression vs Non compression plates Compression plates offer rigid fixation. Has higher risk if not performed perfectly Makes use of bicortical screws Not commonly in use Demerits- bulky, not malleable, gap in lingual plate if overbent 4/21/2013 FAMUREWA & OLADEJO 35

Locking vs non locking plates :

Locking vs non locking plates Conventional plates are non locking(to the screws). Locking plates systems have threaded plate holes that engages(locks) head screws during insertion. 4/21/2013 FAMUREWA & OLADEJO 36

Locking plate system:

Locking plate system 4/21/2013 FAMUREWA & OLADEJO 37

Locking plate system:

Locking plate system Locking plates 2.0 are available in four thickness(with/ without centre space): Small profile Medium profile Large profile Extra-large profile 4/21/2013 FAMUREWA & OLADEJO 38

Locking plates system:

Locking plates system Merits: No precise adaptation to bone is needed Do not disturb cortical plate perfusion(no contact with the bone). 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 39




INSTRUMENTATION 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 41


INSTRUMENTATION (CONTINUED) Drilling machine Drill bits Drill guides (neutral or eccentric) Depth guages Tap Transbuccal instruments (trocar + cannula, guide, retractor) 4/21/2013 FAMUREWA & OLADEJO 42

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PLATE SYSTEMS Synthes Biomet Lorenz KLS Martins Trimed Others Luhr, Leibinger etc 4/21/2013 FAMUREWA & OLADEJO 45

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A 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 46

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Microplates – 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 47

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Compression 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 48

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Reconstruction 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. edentulous jaws) Plates not as thick as 3mm are not recommended for defect bridging May use 2.4, 2.7 or 3.0mm screws depending on system. UFP (Universal Fracture Plate) 2.4mm Thorp system: hollow screws Lag Screws 4/21/2013 FAMUREWA & OLADEJO 49



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Compression plate:

Compression plate 4/21/2013 FAMUREWA & OLADEJO 54


EMERGENCY SCREWS 1.0- 1.2 1.3- 1.7 1.5- 2.0 2.0- 2.4 2.4- 2.7 2.7- 3.0 4/21/2013 FAMUREWA & OLADEJO 55

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Resorbable Fixation System Not really intended for use in the mandible Not for load bearing Use of the Resorbable Fixation system is contraindicated in the presence of: Active or Latent infections. 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 56

Surgical Approaches:

Surgical Approaches Use of existing laceration Intraoral Makes use of a vestibular incision With appropriate instruments and skill, can be used from symphysis to condyle. Use of transbuccal instruments, special contra-angled instruments and endoscope may be necessary in posterior regions. Extraoral Reserved for cases not treatable by intraoral access 4/21/2013 FAMUREWA & OLADEJO 57

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Submental Simple or extended Submandibular Retromandibular Preauricular Facelift/ Rhytidectomy Others 4/21/2013 FAMUREWA & OLADEJO 60

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SYMPHYSIS and PARA~ 2 lag screws/ lag technique A lag screw and a miniplate Archbar and lower border plate 2 miniplates Reconstruction plate (preferably locking) 3D plates 4/21/2013 FAMUREWA & OLADEJO 62


BODY Lag screws One miniplate Two plates One large plate (recon. Plate) 3D plates 4/21/2013 FAMUREWA & OLADEJO 63


ANGLE AND RAMUS Single miniplate Oblique ridge Buccal surface Two miniplates 3D plates Reconstruction plate 4/21/2013 FAMUREWA & OLADEJO 64


CONDYLE Ideally, two miniplates should be applied in a triangular fashion with one plate below the sigmoid notch and one plate along the posterior border. Single DCP Single large profile 2.0 mand plate 3D plate 4/21/2013 FAMUREWA & OLADEJO 65


ORTHOGNATIC SURGERY Different plate systems are available for orthognathic surgeries. 3D plates and plates with angles are frequently utilised Other plates in mandibular modules may be used 4/21/2013 FAMUREWA & OLADEJO 66


RECONSTRUCTION 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. Condylar pieces are available for replacement 4/21/2013 FAMUREWA & OLADEJO 67


LIMITATION Paediatric population Growth disturbance Permanent teeth buds 4/21/2013 FAMUREWA & OLADEJO 68


COMPLICATIONS Nonunion Malocclusion/ malunion Infection Fixation failure Nerve injuries Root injuries 4/21/2013 FAMUREWA & OLADEJO 69

Local Experience???:

Local Experience??? We have applied osteosynthesis principles in both fracture mgt and post tumour ablation reconstructive surgeries. Miniplates, Recon plates(locking& nonlocking) Challenges Cost Ready availability Inadequate armamentarium Theatre space Plate removal??? 4/21/2013 FAMUREWA & OLADEJO 70

Parasymphyseal fracture:

Parasymphyseal fracture 4/21/2013 FAMUREWA & OLADEJO 71

Parasymphyseal fracture:

Parasymphyseal fracture 4/21/2013 FAMUREWA & OLADEJO 72

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Angle fracture:

Angle fracture 4/21/2013 FAMUREWA & OLADEJO 80

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Defect bridging:

Defect bridging 4/21/2013 FAMUREWA & OLADEJO 83

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Primary reconstruction:

Primary reconstruction 4/21/2013 FAMUREWA & OLADEJO 85


QUESTIONS Is MMF necessary for plate application? It is generally necessary but Dimitroulis reported in JOMS (2002) that it is not necessary for angle fracture with good expertise. MMF vs ORIF 4/21/2013 FAMUREWA & OLADEJO 86

PowerPoint Presentation:

1. Dimitroulis G. Management of fractured mandibles without the use of intermaxillary wire fixation. J Oral Maxillofac Surg 2002;60(12):1435-8; discussion 39. 2. Uglesic V, Virag M, Aljinovic N, Macan D. Evaluation of mandibular fracture treatment. J Craniomaxillofac Surg 1993;21(6):251-7. 3. Alpert B, Engelstad M, Kushner GM. Invited review: small versus large plate fixation of mandibular fractures. J Craniomaxillofac Trauma 1999;5(3):33-9; discussion 40. 4. Ehrenfeld M, Roser M, Hagenmaier C, Mast G. [Treatment of mandibular fractures with different fixation techniques--results of a prospective fracture study]. Fortschr Kiefer Gesichtschir 1996;41:67-71. 5. Ellis E, 3rd, Muniz O, Anand K. Treatment considerations for comminuted mandibular fractures. J Oral Maxillofac Surg 2003;61(8):861-70. 6. Hoffman WY, Barton RM, Price M, Mathes SJ. Rigid internal fixation vs. traditional techniques for the treatment of mandible fractures. J Trauma 1990;30(8):1032-5; discussion 35-6. 4/21/2013 FAMUREWA & OLADEJO 87


CONCLUSION ORIF has become the gold standard of trauma care. Several advances have been made in implant science and instrumentation. However, cost still remains a serious challenge Incorrectly applied implants can also cause more harm than good. 4/21/2013 FAMUREWA & OLADEJO 88

References :

References Peterson’s Principles of Oral & Maxillofacial Surgery 2 nd Edition. Atlas of Craniomaxillofacial Fixation Atlas of Craniomaxillofacial Osteosynthesis : Micoplates , Miniplates and Screws AO/ASIF Foundation online resources- AO Foundation website. BIOMET Microfixation 4/21/2013 FAMUREWA & OLADEJO 89

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