Mandibular fracture- diagnosis

Mandibular fracture

1. MANDIBULAR FRACTURES

2. Classification

3. DIAGNOSIS Patient History Clinical Examination Radiographic examination

4. Patient History Type of trauma- Magnitude and direction of the force Change in occlusion Paresthesia or anesthesia of the lip and chin.

5. Clinical Examination – Extra oral Indirect signs Swelling Ecchymosis Erythema Abrasion Laceration Facial deformity Paraesthesia or anaesthesia on one or both side of mandible – inferior alveolar nerve injury Step deformity, crepitus, bone tenderness Inablity to occlude teeth

6. Clinical Examination – Intra oral Coleman’s sign: lingual haemotoma Buccal and lingual sulci – echymosis Step defect in occlusion or alveolus– laceration of overlying mucos and gingival tear. Change of occlusion Mobility Pain, tenderness or limitation in movement

7. Area specific clinical features Fracture at angle Step deformity at last molar tooth Premature dental contact – inablity to close mouth – anterior open bite Unilateral – bilateral angle fracture Ipsilateral – unilateral angle fracture Trismus Retrognathic occlusion and flattened appearance on both surface

8. Fracture of Body Slight displacement – derangement of occlusion Flattened appearance on lateral side Impingement of airways – mylohyoid, digastric or omohyoid pull the fragments posteriorly

9. Fracture of symphysis and parasymphysis Missed – when occlusion is not disturbed Only lingual haematoma (Coleman sign) and bone tenderness is the sign Posterior openbite Posterior crossbite – midline symphysis fracture Retruded chin Severe concussion, loss of tongue control and obstruction of airway

10. Radiographic examination Periapical view Non-displaced linear fracture of body Alveolar process Dental trauma Occlusal view Medial and lateral position of body fracture Anterior posterior displacement of symphysis

11. Panoramic radiographs Most informative Advantages Visualize entire mandible Low dose of radiation Patient education is easy Short time(3-4 min) and can be taken closed mouth. Disadvantages Patient to be upright – impractical for severely traumatized patient Difficult to appreciate: Buccolingual bone displacement or medial condylar displacement Final details are lacking

12. Reverse Towne’s radiograph Ideal for showing lateral or medial condylar displacement Lateral oblique view Fracture of ramus Angle and posterior body

13. Posterior-anterior view Medial or lateral displacement of fracture of ramus, angle, condyle, body and symphysis. Midline or symphyseal fracture well visualised

14. CT scan 3D reconstruction helps understanding degree of displacement as well as reveal fractures not evident in OPG.

15. CBCT or medical CT scans Lesser radiation exposure Better imaging quality Higher sensitivity in identification of fractures Decreased interpretation error Possible in the non ambulatory patient

16. Radiographic Evaluation Ideally need 2 radiographic views of the fracture that are oriented 90’ from one another to properly work up fractures Panoramic and Towne’s CT axial and coronal cuts Single view can lead to misdiagnosis and complications with treatment.

17. TREATMENT PLANNING

18. Sequence of Fracture Repair In 50% patients - more than 1 mandibular fracture. Least displaced mandibular fracture is treated first. The reduction of a tooth-bearing fragment performed first enhance the accuracy of reduction decrease the length of surgery facilitate restoration of the preinjury occlusion result in fewer complications.

19. Treatment objectives Obtain stable occlusion. Establish a full range of mandibular excursive movements. Minimize deviation of the mandible. Produce a pain-free articular apparatus at rest and during function. Avoid internal derangement of the temporomandibular joint Avoid the long-term complication of growth disturbance

20. TREATMENT OPTIONS closed Reduction

21. Closed reduction: indications Favourable fracture Grossly comminuted fracture Severely atrophic mandible Lack of soft tissue overlying fracture site Children – developing dentition Infected fracture Condylar fracture: non displaced

22. Intermaxillary mandibular fixation Indications Favourable fractures. Healthy dentition with sufficient teeth to obtain a stable occlusion Comminuted fractures with multiple small bone fragments that could become displaced with periodontal stripping Patient is compliant and is amenable to immobilization of the jaw for 2 to 6 weeks

23. Erich arch bars using circum-dental wires. Occlusion Interarch wires or elastics

24. Advantages Ease of application Low cost Minimize the distraction of bone at the healing site Maintain intact periosteum over bone Restore normal occlusion Disadvantages: Increase surgical time Require a second procedure to remove the arch bars Only semirigid fixation Risk to surgeon from penetration injuries caused by circumdental and IMF wires Promote poor oral hygiene Pain from loose circumdental wires Delayed healing due to loose IMF wires

25. IMF Self-tapping screws Placed in sound bone in the anterior and posterior vestibular regions Provide a bone anchor for elastics or wires for IMF when establishing and/or maintaining the patient’s occlusion

26. Indications: Pediatric patients with developing tooth buds and lack of dental anchorage. Circum-mandibular wires placed proximal and distal to the fracture and, and then secured to the maxillary skeletal fixation with connector wires. 4 to 6- weeks of stabilization. Minimally displaced mandibular fractures in the tooth-bearing area

27. Advantages Ease of application Decrease in surgical time Low risk of inadvertent skin puncture Stable anchorage promoting realignment of the occlusion Do not loosen with time Promote better oral hygiene Suitable when dentition has been heavily restored with crown and bridge restorations Easy to remove Disadvantages: Risk of tooth-root damage Cannot be used to splint dental alveolar fractures or stabilize loose teeth Maxilla needs to be intact Soft-tissue burying of screw heads in the anterior vestibule Require sound bone stock clear of tooth roots Orthodontic movement of teeth or cracking of enamel where it crosses the incisal tip

28. Contraindications to IMF include: Noncompliant patient Alcoholic patient Seizure disorders Severe pulmonary dysfunction Intellectual disability Psychosis Poor nutrition Pregnancy Patient with multiple system injuries

29. External fixation Rarely used. Nonhealing infected body fracture that requires stabilization. Temporary stabilization before definitive fixation

30. Treatment options Open reduction

31. Open reduction: Indication Complex facial fracture Unfavourable fracture: symphysis, body or angle Displaced bilateral condylar fracture Delayed presentation Malunited mandibular fractures Edentulous mandibular or maxilla Medically compromised patient – severe seizure disorder, psychiatric or neurologic problem

32. Open reduction Controlled reduction R igid fixation. No maxillomandibular fixation, and allows return to early function

33. Approaches for Open reduction Sypmhysis and parasymphysis : intra-oral vestibular approach

34. Stepwise incision through the mucosa first, followed by the incision through the muscles and the periosteum. Two-layer wound closure for muscle and mucosa .

35. Intra-oral- transbuccal incision For body and angle fracture of mandible. Medial to buccal fat pad and lateral to temporalis muscle.

36. Extra-oral submandibular – Risdon incision For body and angle fracture of mandible. Also known as Transcervical access of the submandibular standard approach.

37. Sharp dissection stepwise through skin, platysma, and superficial cervical fascia. Ligation of the facial vein and/or artery. The bone surface is reached in a layer underneath the superior cervical fascia.

38. Internal fixation Healing time is directly related to the size of the gap between bone and interfragment motion. Two goals of rigid internal fixation are to stabilize bone fragments to minimize movement To have smallest gap possible between fracture margins

39. Miniplates along the lines of osteosynthesis

40. For a body fracture, Champy’s technique places a single plate in the zone of tension. In symphysis 2 plates are used, separated by 4 to 5 mm, to neutralize the moments of torsion. Bend the plates so they lie passively on bone before monocortical screws. When there is lack of bony contact following fracture reduction because of bone loss or there is significant comminution- rigid plates along inferior border of mandible using bicortical screws.

41. If the plate is not passively adapted to the underlying bone the engaging of the screw will create pressure that displaces the fracture, resulting in a poor reduction and malocclusion. the bone underlying the plate can resorb and the fixation can become loose before adequate fracture healing. Locking plates and screws

42. Lag screws Body fracture in a sagittal plane with splitting of the buccal and lingual cortices, 2 or 3 lag screws Counteract moments of torsion in the symphysis

43. Transosseous wiring Several weeks of postoperative inter- maxillary fixation Higher incidence of post treatment infection.

44. MANAGEMENT OF FRACTURES OF THE EDENTULOUS MANDIBLE Less than 1% to 5% of all mandibular fractures. Greatest alveolar bone resorption - body. Most common site of fracture

45. Treatment of choice Clinician’s prior experience

46. Closed reduction options Isolated mandibular fixation using the patient’s complete lower denture with circum- mandibular wires to stabilize the fracture Customized gunning splints External pin fixation

47. Complications

48. Hemorrhage Soft tissue damage Floor of mouth and neck spaces

49. Facial nerve injury Palsy/ paralysis

50. Infection Fractures involving tooth-bearing Preoperative and perioperative Incidence of infection in patients with compound fractures mandible - 50%. Tobacco and alcohol use are risk factors.

51. Avascular necrosis, osteitis, osteomyelitis Periosteal and medullary blood supply

52. Temporomandibular joint ankylosis Stiffness, pain, limitation in movement Aseptic necrosis of articular surfaces. Bony proliferation and scarring Fibro-osseus ankylosis Management: Replacement of condylar head with costal chondral graft/ alloplastic TM joint replacement

53. Nonunion of the Mandible Incidence 2%–32%. Most common site- body. Predisposing factors Multiple fracture sites Delayed treatment Inadequate reduction Inadequate fixation Noncompliance of the patient (premature release of IMF, poor oral hygiene) Alcohol or drug abuse (poor nutrition) Systemic disease (diabetes) Misdiagnosis

54. Treatment of non union: Stabilization of the mandible with either internal or external rigid fixation, with a bone graft if a bony defect has developed.

55. Neurosensory changes Prevalence of postinjury/pretreatment inferior alveolar nerve (IAN) injury- 5.7% to 58.5%. The prevalence of IAN neurosensory deficit after fracture treatment- 0.4% to 91.3% Risk factors for worsening A fracture displaced 5 mm or greater – 6x A normal preoperative neurosensory score – 25x Open reduction/internal fixation – 40x