Temporomandibular joint ankylosis and its management

Detailed discussion on diagnosis and management of TMJ ankylosis. Surgical anatomy and applied aspects of TMJ is discussed. Reconstruction of ramus-condyle unit is also discussed. Compications of TMJ surgery are also discussed

1. TMJ ankylosis and its management Presented by: Dr Dibya Falgoon Sarkar 3 rd year Postgraduate student Department of Oral & Maxillofacial Surgery

2. Introduction Temporomandibular joint ankylosis is a pathologic condition where the mandible is fused to the fossa by bony/ fibrotic tissues. ( Movahed R, Mercuri LG. Management of temporomandibular joint ankylosis . Oral and Maxillofacial Surgery Clinics. 2015 Feb 1;27(1):27-35 .) Ankylosis is a Greek word that literally means “stiff joint”. TMJ a nkylosis interferes with: Mastication Speech Oral hygiene Growth & development Ankylosis can be potentially life-threatening when we want to acquire an airway during an emergency.

3. Epidemiology of TMJ ankylosis in India Overall prevalence: 0.46 per 1000 in the 3-15 years’ age group. Age distribution: 3-63 years. Most common age group: 10-15 years. Male : Female: 1:9 Birth/ childhood trauma was the major causative factor. (Gupta VK, Mehrotra D, Malhotra S, Kumar S, Agarwal GG, Pal US. An epidemiological study of temporomandibular joint ankylosis . National journal of maxillofacial surgery. 2012 Jan;3(1):25 .)

4. Etiology of Ankylosis of TMJ Trauma : At birth (forceps delivery) Haemarthrosis Condylar fracture Infections Chronic suppurative otitis media Abscess around joint Osteomyelitis of jaw Actinomycosis Parotitis 3. Inflammation: Rheumatoid arthritis Osteoarthritis Septic arthritis 4. Systemic diseases : Small pox Ankylosis spondylitis Beri beri 5. Other causes: Bifid condyle Prolonged trismus Burns

5. Trauma- The predominant cause of TMJ ankylosis Rowe’s series of 46 cases, out of which 31 resulted from trauma Sada et al study of 146 cases, out of which 58% accounted from trauma Sawhney’s series of 70 cases, out of which 69 were the result of trauma. Factors contributing to ankylosis: Age of patient Site and type of condylar fracture Length of immobilization Damage to the articular disc

6. How trauma leads to TMJ ankylosis

7. Classification of TMJ ankylosis Kazanjian’s classification: Rowe classified TMJ ankylosis according to: Topazian’s classification: True ankylosis False ankylosis When there are fibrous/ osseous adhesions between the surface of the TMJ When the ankylosis is due to other pathologies not directly related to the joint. Location of problem Type of tissues involved Extent of fusion Intra-articular Osseous Complete Extra-articular Fibrous Incomplete Both Type I Type II Type III Affects the condyle only Intermediate type Affects condyle. coronoid and cranial base

8. Sawhney’s grading of TMJ ankylosis (1986) ( Sawhney CP. Bony ankylosis of the temporomandibular joint: follow-up of 70 patients treated with arthroplasty and acrylic spacer interposition. Plastic and reconstructive surgery. 1986 Jan;77(1):29-40 .)

9. History: Accurate history is important to differentiate between true and pseudoankylosis History of trauma directly to the joint or indirectly to the chin History of ear infection History of forceps delivery Extracapsular causes like zygomatic arch fractures, OSMF should be ruled out Clinical examination : Restricted mouth opening with difficulty in mastication and jaw movements. Patients often have associated obstructive sleep apnoea . Patients are often seen with craniofacial syndromes, skeletal deformities and psychological distress. Patients often come with a scar over chin. Diagnosis of TMJ ankylosis

10. Unilateral ankylosis Bilateral ankylosis Obvious facial asymmetry Mandible is symmetrical but micrognatic Deviation of chin to affected side Bird-face deformity Flattening and elongation of unaffected side Retrognathic mandible Well defined antegonial notch Prominent antegonial notch bilaterally Absence of condylar movements on affected side Inability t o open mouth Unilateral posterior cross-bite B/L Class II malocclusion, multiple carious teeth, crowding ± anterior open bite Reduced mouth opening Increased chin throat angle

11. Radiographic investigations Orthopantomograph - will show both the joints which can be compared in unilateral cases Lateral oblique view- will show anteroposterior dimensions of the ankylotic mass. Elongation of coronoid process also seen Posteroanterior view- will show the mediolateral extent of the ankylotic mass and also highlights asymmetry in unilateral cases. Lateral Cephalogram - Helpful to evaluate the associated skeletal deformities. CT scan- Helpful guide as it gives the picture of the ankylotic mass in 3D and its proximity to other anatomical structures.

12. Management of TMJ ankylosis Infancy Childhood (Growing age group) Adults Cause: Agenesis of the TMJ (rare) Birth trauma Infection Cause: Trauma Infection Cause: Trauma Infection Aim of treatment: Restore movement and function Reconstruction may be done later Aim of treatment: Restore movement and function Reconstruction of the TMJ Correction of occlusal and cosmetic deformity: Early teen: Distraction osteogenesis, myofunctional appliance Late teen: Orthognathic surgery, Distraction or both Aim of treatment: Restore movement and function Reconstruction of the TMJ If OSA present, distraction may be done at first followed by release of ankylosis and TMJ reconstruction.

13. Surgical anatomy of Temporomandibular Joint

14. Bony Components Components of TMJ Soft-tissue components Condyle of mandible Articular eminence Glenoid fossa Articular disc Joint capsule Ligaments Muscles

15. Unique features of TMJ Its articular surface covered by fibrocartilage instead of hyaline cartilage. The right and left TMJ form a bicondylar articulation and functions together as one unit. Only joint in human body to have a rigid endpoint of closure that of the teeth making occlusal contact. In contrast to other diarthrodial joints TMJ is last joint to start develop, in about 7th week in utero.

16. Important structures related to TMJ Nerves: Facial nerve Auriculotemporal nerve Inferior alveolar nerve Vascular structures: Middle meningeal artery Internal maxillary artery Superficial temporal artery Masseteric artery

17. Facial Nerve The main trunk of the facial nerve exits from the skull at the stylomastoid foramen. Surgical landmarks for identification of facial nerve: Tragal pointer - The main trunk of the facial nerve is located 1 cm anteroinferior and 1 cm deep to the tip of the tragal cartilage. Digastric ridge- The main trunk is just superior to the attachment of the posterior belly of the digastric muscle to the digastric groove. This landmark also marks the approximate depth of the facial nerve. Tympanomastoid suture line - The nerve lies 6 to 8 mm deep to the inferior end of the tympanomastoid suture line.

18. Facial Nerve Surgical landmarks for identification of facial nerve: Stylomastoid foramen - The base of the styloid process is 5 to 8 mm deep to the tympanomastoid suture line. The facial nerve can be identified as it exits the stylomastoid foramen and passes over the posterolateral aspect of the styloid process. Mastoid - For revision cases, extensive tumors or, as a last resort, a mastoidectomy can be performed to locate the vertical segment of the facial nerve, which can then be followed as it exits the mastoid.

19. Relation of VII nerve with TMJ Approximately 1.3 cm of the facial nerve is visible to surgeon until it divides into temporofacial and cervicofacial branches According to Alkayat & Bramley’s classic article (1979)

20. Radiologic study by Miloro et al

21. Applied Aspects The temporal branch of the facial nerve emerges from the parotid gland and crosses the zygoma under the temporoparietal fascial to innervate the frontalis muscle Postsurgical palsy manifests as an inability to raise the eyebrow, close the eyelid and  ptosis of the brow. Damage to the zygomatic branch results in temporary or permanent paralysis to the orbicularis oculi and may require temporary patching of the eye to prevent corneal desiccation and abrasion.

22. Auriculotemporal Nerve first branch of the mandibular nerve after it exits the foramen ovale . supplies sensation to the skin in the temporal and preauricular region, the anterior external meatus The auriculotemporal nerve provides most of the innervation to the capsule of the temporomandibular joint itself Branch of mandibular nerve, post division Radiographic assessment of the exact course of this nerve through the mandible is necessary if screws will be placed through the ramus as is necessary for prosthetic joint replacement Inferior Alveolar Nerve

23. Vascular anatomy of TMJ Superficial temporal artery and vein: are routinely ligated during preauricular approaches. Internal maxillary artery: is usually not encountered unless a condylectomy is performed. If a condylectomy is performed, Dunn‐ Dautrey retractors are used as the  internal maxillary artery normally runs-approximately 3 mm medial from the midsigmoid notch.

24. Talebzadeh N, Rosenstein TP, Pogrel MA. Anatomy of the structures medial to the temporomandibular joint. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontics. 1999 Dec 1;88(6):674-8.

25. Masseteric artery A careful dissection of 16 intact human cadaveric head specimens was done. The location of the masseteric artery was then determined in relation to 3 points process: 1 ) the anterior-superior aspect of the condylar neck = 10.3 mm; 2 ) the most inferior aspect of the articular tubercle = 11.4 mm; 3 ) the inferior aspect of the sigmoid notch = 3 mm. Journal of Oral and Maxillofacial Surgery. 2009;67 (2) : 369–371

26. Surgical Approaches to TMJ Preauricular : Dingman’s , Blair’s, Thoma’s , Al- kayat and Bramley’s, Popowitch’s P ostauricular Endaural approach Post ramal / Hind’s approach Submandibular/Risdon’s approach Hemicoronal B icoronal

27. Preauricular Approach Basic incision was given by Dingman (1951) Blair & Ivy modification– “Inverted hockey stick “ incision. Facilitate exposure of arch along with condylar area. Thoma in 1958 Angulated vertical incision. -carried out across zygomatic arch infront of ear to avoid main trunk of facial nerve

28. Alkayat and Bramley Modified Preauricular Incision ( Al‐ Kayat A, Bramley P. (1980) A modified preauricular approach to the temporomandibular joint and malar arch. Br J Oral Surg , 17:91 .) 1. Reduced haemorrhage 2. Provision of donor site for temporalis fascia 3. Better cosmetic result 4.Lesser chance of facial nerve injury

29. Facial nerve branches are not damaged

30. Post auricular approach Introduced by Bockenheimer Advantage: Excellent exposure of the entire joint and the ability to camouflage the scar in patients who have a tendency to form keloids . Better posterior exposure of TMJ Disadvantage: Auricular stenosis Should not be used in the presence of joint infection or chronic otitis externa

31. Post-auricular approach

32. Endaural Approach Lempart (1938) Short facial skin incision extending in to ext. auditory meatus Advantage: Excellent cosmetics and posterolateral exposure Disadvantage: Meatal stenosis or chondritis I njury to the branches of the facial nerve Care must be taken not to incise the tragal cartilage because a perichondritis or poor wound healing may result.

33. Post-ramal/ Hind’s Approach E.C Hinds & Girotin (1967) Indications – Condylar neck fractures Condylotomy Vertical ramus osteotomy Incision- 1cm behind ramus of mand. and extends 1cm below the lobe of ear. Advantages: Highly cosmetic, excellent visibility and accessibility. Note: Injury may occur to posterior facial vein and main trunk of facial nerve.

34. Structures encountered during Hind’s approach

35. Combination of Retromandibular + Endaural Approach Indication: For additional access to the temporomandibular joint for open fracture reduction, costochondral grafting, total alloplastic joint reconstruction, or tumor resection. When combining both incisions, the surgeon must leave an intervening bridge of tissue that extends inferiorly at least 3 cm from the lowest point of the bony external auditory canal to protect VII nerve

36. Submandibular Risdon’s Approach Risdon (1934) Mainly used for neck of condyle & ramus region Incision: Placed one‐finger breadth below the angle of the mandible ensuring avoidance of the marginal mandibular nerve

37. Relations of marginal mandibular nerve ( Dingman RO, Grabb WC. Surgical anatomy of the mandibular ramus of the facial nerve based on the dissection of 100 facial halves. Plastic and Reconstructive Surgery. 1962 Mar 1;29(3):266-72 .) The marginal mandi-bular (MMN) branch of the facial nerve, posterior to the facial artery, passed above the inferior border of the mandible in 81% of dissections It ran superficial to the facial vein in 98% cases Damage to MMN: The patient is unable to depress the lower lip and show the mandibular anterior teeth.

38. Surgical techniques Surgical goals for correction of ankylosis : To free up the ankylosis To return the patient to function To reconstruct the joint and restore the vertical height of the ramus To prevent recurrence To restore normal facial growth pattern To improve esthetics and rehabilitate the patient Release of ankylosis is done by 2 methods: Condylectomy : Only the condyle is detached and removed. Osteoarthrotomy (Gap arthroplasty): Excision of the entire joint and/ an adequate amount of bone below the joint.

39. Anaesthesia considerations during TMJ ankylosis surgery Airway often gets compromised in TMJ ankylosis cases Fiberoptic intubation/ elective tracheostomy is preferred. Hypotensive anaesthesia is preferred (Mean intraop arterial pressure: 55-60mm of Hg) Avoid long acting muscle relaxants until access to the mandible is gained. This will help in identification of the facial nerve branches.

40. Condylectomy Condylectomy consists of excision of the condyle only. Indications: Severe osteoarthritis Various other types of arthritis e.g : Rheumatoid arthritis Malunited condylar fractures with limitation of motion and pain during mastication Fibrous ankylosis cases where the articular space has not been completely eliminated. Disadvantages of condylectomy : Loss of vertical height of ramus In bilateral condylectomy cases, there will be anterior open bite In unilateral cases: Deviation of chin to affected side on mouth opening.

41. Osteoarthrotomy (Gap arthroplasty) Creates an anatomical gap in the ankylosed segment to form an artificial joint space. Commonly done in complete ankylosis cases Key points: A gap of about 1-1.5cm is created to and is not interposed with any material. B ony landmarks to be identified: Zygomatic arch first followed by neck of the condyle and sigmoid notch/ anterior border of ascending ramus (if ankylotic mass is large). Dunn retractor may be engaged at the neck of the condyle to protect the surrounding tissues and maxillary artery. Two horizontal bony cuts are made in the most superior aspect of the ramus. Inferior osteotomy cut should be made first followed by the superior cut. Medial portion of ankylotic mass must be completely removed.

42. Complications of Gap arthroplasty: Excessive gap may lead to anterior open bite Reankylosis if physiotherapy is not done postopertively

43. Interpositional arthroplasty Principle: An interpositional material is placed between the bone ends after excision of the ankylotic mass to avoid contact and minimize chances of reankylosis . Interpositional material can be: Autogenous: Temporalis muscle/fascia, costochondral graft, dermis graft, fascia lata , sternoclavicular grafts. Alloplastic: 1. Metallic: Titanium, gold 2. Nonmetallic : Silastic , acrylic, etc. Complications: Second surgical site morbidity Foreign body reactions seen with alloplasts

44. Kaban’s protocol Aggressive excision of the fibrous/ bony ankylotic mass Coronoidectomy on affected side Coronoidectomy on opposite side if steps 1 and 2 do not result in maximum interincisal opening of >35mm Lining of joint with temporalis fascia/ the native disc Condylar reconstruction with either transport distraction osteogenesis/ costochondral graft with rigid fixation Early mobilization; if DO used; if CCG used, early mobilization with minimal intermaxillary fixation (not >10 days) Aggressive physiotherapy Kaban LB, Bouchard C, Troulis MJ. A protocol for management of temporomandibular joint ankylosis in children. Journal of Oral and Maxillofacial Surgery. 2009 Sep 1;67(9):1966-78.

45. Postoperative physiotherapy Physiotherapy is as important as the surgery itself. The patient should be encouraged to start active active exercises as soon as it can be tolerated. Initially: Pressure with finger/ simple finger exercises Later: Ice-cream sticks, tongue blade, Heister’s jaw opener for forceful mouth opening. Medications can be given to relieve pain and enable movements. Heat application to the region prior to exercise permits easy movement to relieve muscle spasm.

46. Reconstruction of Acquired Temporomandibular Joint Defects Factors to be considered during selection of reconstruction technique: Age of the patient Severity of the problem Surgeon’s experience Socioeconomic factors Ability to perform postoperative physiotherapy

47. Costochondral graft Most widely used autogenous graft for TMJ reconstruction Advantages: 1.Most widely used 2. Has a cartilage cap, mimicking both the bone and cartilaginous components 3. Has intrinsic growth potential (Useful in children ) 4. Easy accessibility and adaptation 5. Gross anatomic similarity to the mandibular condyle Limitations: Unpredictable growth Poor bone quality Possible separation of cartilage from bone Possible donor-site complications: pleural tear, pneumothorax, pleural effusion, atelectasis, empyema. Reankylosis : 5-39% of cases

48. Procedure Ideal rib for harvesting: Right sixth rib Reasons for preferring right 6 th rib: Aesthic : Incision can be placed in the inframammary crease Least muscle attachment present compared to other ribs Length is satisfactory Postoperative pain is less likely to be confused with cardiogenic pain

49. Sternoclavicular joint grafts Advantages: Better anatomic and physiologic characteristics than CCG Contains a cartilaginous cap Has the potential for growth (Useful in children ) 5. Probability of regeneration at donor site Limitations: Unacceptable location of surgical scar Donor-site complications: damage to the great vessels, instability of the shoulder, clavicle fracture

50. Iliac crest grafts Anterior iliac crest grafts are preferred as it can be harvested without changing patient position. Advantages: Has a cartilage cap, mimicking both the bone and cartilaginous component Has potential for growth (Useful in children) More suitable for large mandibular defects Limitations: Donor-site complications: altered gait, poor scar/bone contour, herniation of abdominal contents, ilium fracture, peritonitis, retroperitoneal hematoma Second surgical site

51. Coronoid process Many times we perform removal of the elongated coronoid process in TMJ ankylosis . Advantage: Avoidance of secondary surgical site and associated donor complications Less evidence of graft resorption Limitations: Relatively pointed architecture No long-term studies are found No growth center

52. Transport distraction osteogenesis Pre-requisite: Patient must have a large enough residual bone to allow placement of 2 screws to control and transport the DO segment. Advantage: No need for interpositional material No secondary donor site morbidity Patient can function during distraction osteogenesis Simultaneous correction of secondary deformities Limitations: Lengthy procedure Patient cooperation is a must Complications: Failure of hardware Lack of consolidation

53. Vascularized bone grafts Second metatarsophalangeal joint free flap: Advantages: Combination of articular cartilage & bone Fitting anatomy because of small size Has potential for growth Limitations: Donor-site complications: esthetic loss of a toe Simple hinge joint does not follow the same movements as the TMJ (Potter JK, Dierks EJ. Vascularized options for reconstruction of the mandibular condyle. InSeminars in plastic surgery 2008 Aug (Vol. 22, No. 03, pp. 156-160). © Thieme Medical Publishers.)

54. Vascularized bone grafts (Potter JK, Dierks EJ. Vascularized options for reconstruction of the mandibular condyle. InSeminars in plastic surgery 2008 Aug (Vol. 22, No. 03, pp. 156-160). © Thieme Medical Publishers .) Free fibula flap: Not reported for condyle reconstruction in ankylosis cases Potter & Dierks recommend fibula as a good option for defects of mandibular condyle when: W ound beds are compromised Nonvascularized bone grafts are contraindicated. Limitations: Lacks articular cartilage Donor-site complications: ankle stiffness, instability and weakness, numbness of the lateral side of the leg, pedal ischemia, foot edema

55. Vascularised options for reconstruction of Mandibular condyle (Potter JK, Dierks EJ. Vascularized options for reconstruction of the mandibular condyle. InSeminars in plastic surgery 2008 Aug (Vol. 22, No. 03, pp. 156-160). © Thieme Medical Publishers.) Type of defect Description Choice of vascularized graft Class I Defect of the mandibular condyle only. The condylar replacement would articulate against the undersurface of the intact articular disk. Contoured fibular flap Class II Defect of the condyle & the articular disk. A reconstruction of the condyle would articulate against the fibrocartilage lining of the glenoid fossa and articular eminence. Need for simultaneous proximal mandible reconstruction?- Contoured fibular flap with auricular cartilage interposition graft Reconstruction of TMJ structures only?- Second metatarsal transfer Class III Defect that includes the condyle, disk and glenoid fossa of the temporal bone. A reconstruction of the floor of the middle cranial fossa as well as a condylar replacement may be necessary to restore the temporomandibular articulation. Need for simultaneous proximal mandible recon- struction ? Nonvascularized osseous reconstruction of glenoid fossa: interpositional soft tissue graft; contoured fibular flap Second metatarsal transfer with fibular flap - Reconstruction of TMJ structures only? - Second metatarsal transfer

56. Alloplastic reconstruction of TMJ (Quinn PD. Alloplastic reconstruction of the temporomandibular joint. University of Texas at Dallas, Southwestern Medical Center ; 1999) Surgeons often use stereolithographic models for construction of custom-fitted total joint prostheses in a two- staged surgical procedure

57. Alloplastic reconstruction of TMJ (Quinn PD. Alloplastic reconstruction of the temporomandibular joint. University of Texas at Dallas, Southwestern Medical Center ; 1999)

58. Stock prostheses Custom-made Prostheses Make fit Made to fit Lower cost Higher cost Shorter treatment time frames Longer treatment time frames Removal of bone No or minimal removal of bone More difficult to obtain primary stability Easier to obtain primary stability Potential micromovement No micromovement Placement versatility Less placement versatility Potential for longer surgical time Potential for less surgical time Limited use for large defects Excellent for large or difficult anatomic defects

59. Importance of fat graft in prevention of heterotopic bone formation In 1992, Wolford developed the technique of placing autogenous fat grafts around the TMJ prostheses to prevent postsurgical heterotopic bone and fibrosis development. Pedicled buccal fat grafts can also be used. Rationale: To obliterate the dead space around the joint prosthesis, thus preventing the formation and subsequent organization of a blood clot/ hematoma (which calcifies later). (Wolford LM, Karras SC. Autologous fat transplantation around temporomandibular joint total joint prostheses: preliminary treatment outcomes. Journal of oral and maxillofacial surgery. 1997 Mar 1;55(3):245-51 .)

60. Factors which prevent reankylosis Radical resection of the ankylotic mass. Condylar and disc reconstruction. Various studies have proved that restoration of the vertical ramus height by condylar and disc reconstruction with different interpositional materials significantly reduces possibility of recurrence. Ipsilateral and/or contralateral coronoidectomy . These operations are often necessary according to the passive maximal mouth opening intraoperatively because the coronoid process may be too large to affect the mouth opening in long-standing cases. Filling the remaining dead space with buccal fat pad. Hematoma formation and ossification in the dead space of the surgical site may contribute to the re- ankylosis (Wolford et al., 2008). In certain long-standing cases, extended elevation or even cutoff of masseteric muscle is required. Early postoperative exercises and appropriate physiotherapy are critical for preventing reoccurrence of ankylosis .

61. One-stage vs Multistage treatment in TMJ ankylosis Post- ankylotic facial deformities include: Micrognathia , reduced facial height, poor jaw–neck definition, chin shift to the affected side, and occlusal discrepancies. In unilateral cases, a cant of the occlusal plane is frequently observed due to mandibular hypoplasia on the affected side, and hence a secondary ipsilateral vertical deficiency in the maxilla is seen. ( Mehrotra D, Vishwakarma K, Chellapa AL, Mahajan N. Pre-arthroplasty simultaneous maxillomandibular distraction osteogenesis for the correction of post- ankylotic dentofacial deformities. International journal of oral and maxillofacial surgery. 2016 Jul 1;45(7):820-7 .) Correction of TMJ ankylosis and facial deformities can be done in: One-stage surgery provides simultaneous release of ankylosis and correction of skeletal deformities. Multi-staged treatment protocol involves, releasing of ankylosis first . This is followed by orthodontic treatment and correction of secondary deformities at a later stage or vice versa .

62. One-stage vs Multistage treatment in TMJ ankylosis

63. One stage treatment Multi-staged treatment Advantages: Provides more immediate and complete satisfaction to the patients. Psychological benefits Less expensive Advantages: Gives the clinician ample opportunity to monitor relapse or malocclusion development. Provides a more stable postsurgical outcome in the appropriately selected patient population Facilitate early and active postoperative exercise of mouth opening. Useful in obstructive sleep apnoea Disadvantages: Often results in an unstable proximal condylar segment as a remaining problem during the distraction process Intermaxillary fixation is often necessary for bone healing, which hampers mouth opening exercises and increases the incidence of recurrence. Longer operation time. Disadvantages: More prolonged span of treatment period More expensive Zhu S, Wang D, Yin Q, Hu J. Treatment guidelines for temporomandibular joint ankylosis with secondary dentofacial deformities in adults. Journal of Cranio -Maxillofacial Surgery. 2013 Oct 1;41(7):e117-27.

64. One staged treatment

65. Multi-staged treatment

66. Management of TMJ ankylosis in patients with Obstructive Sleep Apnoea (OSA) Many patients present with a triad of TMJ ankylosis , micrognathia and OSA. Incidence of reankylosis due to non-compliance for active jaw physiotherapy has been high in this group of patients with OSA. Reason for higher incidence of reankylosis in this group: Patients generally have severe AHI (>30) and PAS <4mm This leads to a choking sensation due to blockage of the airway during jaw opening exercise which reduces patient compliance Thus, in these patients with reduced PAS, severe AHI and OSA, it is better to perform distraction osteogenesis of the retrognathic mandible at first followed by release of TMJ ankylosis . (Andrade NN, Kalra R, Shetye SP. New protocol to prevent TMJ reankylosis and potentially life threatening complications in triad patients. International journal of oral and maxillofacial surgery. 2012 Dec 1;41(12):1495-500 .)

67. (Andrade NN, Kalra R, Shetye SP. New protocol to prevent TMJ reankylosis and potentially life threatening complications in triad patients. International journal of oral and maxillofacial surgery. 2012 Dec 1;41(12):1495-500 .)

68. Complications of TMJ Surgery During anaesthesia: Difficult intubation due to restricted mouth opening. Aspiration of blood during extubation . We must place a throat pack immediately after releasing the ankylosis . Danger of tongue falling back and obstructing the airway after extubation . We should consider delayed extubation or use oropharyngeal airway. During postop follow up: Infection Open bite Reankylosis Facial nerve palsy Prosthesis failure Graft resorption

69. Complications of TMJ Surgery During surgery: Haemorrhage due to damage to blood vessels: Internal maxillary artery Superficial temporal vessels Inferior alveolar vessels 2. Damage to external auditory meatus 3. Nerve injury: Zygomatic and temporal branches of facial nerve, auriculotemporal nerve 4. Damage to glenoid fossa and accidental entry into the middle cranial fossa.