This is about mandible fx, treatments, studies

Mandible fx

1. Mandibular Fractures

2. History Earliest known writings on mandibular fractures appeared in 1650 BC by Edwin Smith Papyrus Hippocrates  manual reduction of mandibular fractures Salicetti  First surgeon to recognize the importance of MMF outline in textbook Cyrurgia (1476) Gilmer in US in 1887  reintroduction of concept of interdental wire and basic principles of reduction, stabilization and fixation Miloro , M., Ghali , G. E., Larsen, P. E., & Waite, P. (2004).  Peterson’s principles of oral and maxillofacial surgery.  (4th ed. / editor, Michael Miloro / associate editors, G.E. Ghali , Peter Larsen, Peter Waite.). B C Decker.

3. History continued Major advancements in WWI and WWII Germany 1914  225 beds at Dusseldorf dedicated to treatment of of wounds of face and jaws Charles Valadier 1916 (France)  Established jaw fracture unit at Wimereux Kazanjian 1917 (Western Front)  Combined dental splints with transosseous wires and plaster head caps able to achieve to bony union Harold Gillies (1915)  established first comprehensive maxillofacial unit at Cambridge Hospital Miloro , M., Ghali , G. E., Larsen, P. E., & Waite, P. (2004).  Peterson’s principles of oral and maxillofacial surgery.  (4th ed. / editor, Michael Miloro / associate editors, G.E. Ghali , Peter Larsen, Peter Waite.). B C Decker.

4. Epidemiology Developed vs developing (MVCs) Men vs. Women Men have 4-fold higher incidence of mandibular fracture Shifts within age groups Older women  falls Younger men  sports injuries Overall: Assaults MVCs Falls

5. Anatomic distribution of Mandibular Fractures

6. Biomechanics Compressive and Tensile Zones of the Mandible

7. Biomechanics Punch to parasymphysis /symphyseal region. Compressive strain on buccal aspect; Tensile strength on lingual; Fracture to occur on lingual and propagate to buccal

8. Schools of Thought For Treatment The Splint Age (1866-1918) The Wire Age (1918-1968) Interdental fixation Erich Arch Bars The Metal Plate Age and the Evolution of Modern Systems of Internal Fixation (1968- Present) AO/ASIF: German School of Thought Dynamic compression plating Locking plates Functional Fixation, Michelet and Champy Ideal line of osteosynthesis = max. tensile stress from oblique ridge along base of alveolus to mental foramen Miniplate fixation Miloro , M., Ghali , G. E., Larsen, P. E., & Waite, P. (2004).  Peterson’s principles of oral and maxillofacial surgery.  (4th ed. / editor, Michael Miloro / associate editors, G.E. Ghali , Peter Larsen, Peter Waite.). B C Decker.

9. Operative Management: Goals Restore patient to form and function pre-injury occlusion Achieve osseous union predictably

10. Decision Making: Closed Treatment with MMF vs ORIF Study conducted evaluating a total of 336 patients: 2 groups (MMF vs ORIF) Followed prospectively for 12 months Failed to clear overall benefit of ORIF of moderately displaced fractures over MMF Major limitation: Many patients lost to follow up

11. Decision Making: Closed Treatment with MMF vs ORIF MMF  no debate that it is a safe, reliable, cost-effective treatment modality Must consider other factors: Patient Compliance: Gender, illicit drug use, geographical barriers Degree of displacement MMF can be time-consuming and risk of skin puncture Advent of IMF screws Found to be a safer alternative to wiring methods with a significant reduction in glove perforation rates and decrease in operative time Most recently  Hybrid arch bars Alternative to IMF when cross arch stabilization is indicated

12. Conclusions on Decision-Making In general, Erich arch bars, IMF screws, “hybrid” arch bars, interdental Stout wires, and manual reduction alone all have efficacy for achieving favorable bony union in the ORIF of selected mandible fractures

13. Principles of Rigid Internal Fixation Rigid stability vs functional stability Rigid  no movement Functional  when movement is possible across fracture gap but balanced by external forces Excessive mobility will lead to bone resorption and fibrous union Load-sharing and Load-bearing Sharing  fixation system in conjunction with stabilizing forces provided by anatomic abutment of non-comminuted fracture segments Bearing  functional stability that is provided solely by fixation system

14. Indications of Load-Bearing Fixation vs Load-Sharing Load Bearing Indications Load Sharing Indications Fractures with comminuted segments No comminution Atrophic mandibular fractures No bone defects present Fractures with avulsed or missing segments = continuity defect Intact bone cortices are opposed to another after fracture reduction (bone to bone contact) *Majority of fractures can be managed with load-sharing

15. Teeth in Line of Fracture: To Extract or Not? Evidence suggests that teeth in line fracture may be retained providing that that do not interfere with favorable reduction, stabilization and fixation of the fracture and are not grossly mobile or infected.

16. Isolated Mandibular Symphysis, Parasymphysis and Body Fractures Non-comminuted fractures typically accessed via transoral approach Patients with IMF using arch bars, IMF screws, etc., bone reduction forceps applied to reduce osseous segments in cases of linear fracture Medial pressure applied to the angles in cases comminution or when condyles involved to prevent facial widening

17. Mandibular Angle Fractures Ideal treatment of angle fractures has been controversial Highest complication involves presence of 3 rd molar Treatment options include: Placement of reconstruction plate along inferior border Placement of compression plate along inferior border Placement of ladder plate Placement of miniplate along superior border Placement of miniplates along superior and inferior border

18. Mandibular Angle Fractures Edwards Ellis had a series of clinical papers starting in 1993 evaluating each technique Highest complication rate and most significant type of complications occurred when using two dynamic compression plates (32%) A single, non-compression miniplate placed in Champy style via transoral approach yielded a complication rate of only 2.5%

19. Complications Infection (1%-32%)  most common complication Substance abuse, non-compliance, smoking, significant delay in treatment Study performed by Hurrell et al in 2018 definitive treatment within 3-5 days after trauma has been shown to be optimal in minimizing the rate of infection Evaluated 359 mandibular fractures Assessed wound dehiscence, hardware exposure, local post-operative infection, trismus, nerve damage 0 to 41 days (with average of 5 days)

20. Complications Most infections are polymicrobial Most common: Staphylococcus, alpha- hemolytics Streptococcus, Bacteroides Treatment: Current evidence support IV Unasyn or Cefazolin + Flagyl Clindamycin  debatable  increased resistance Remove hardware Malunion Non-compliance, violations of reduction, stabilization and fixation Tx: Osteotomies generally indicated Nonunion Uncommon Tx: debridement and stabilization and application of rigid internal fixation with reconstruction plate

21. Advancements Intraoperative 3D Imaging Intra-operative CT scanner and 3D C-arm Useful for confirming hardware position and verifying key landmarks 83 patients evaluated using C-arm By using intra-operative C-arm, 4 patients underwent intra-operative revision without complications

22. Advancements Intraoperative Navigation/Surgical Navigation Effective in cases where one side of face is unaffected CT scan can be imported into navigation system and the unaffected side then undergoes an axial flip and virtually mirrored on the pathological side Navigation probe can be placed along the repair throughout the reconstruction Limitations include: Accessibility Not well studied Panfacial traumas 1 mm margin of error in periorbital cases https://www.brainlab.com/webinars/benefits-of-navigation-and-intraoperative-imaging-in-cranio-maxillofacial-surgery/

23. Advancements VSP Advent of VSP has led to more immediate access to stereolithic models and therefore more applications for the trauma surgeon Precision achieved with CAD/CAM technology Plates to be adapted to stereolithic model In house printing avg time 2 hours in recent study by Bergeron et al May 2023 25 models for 16 trauma patients