RECURRENT TMJ DISLOCATION

• OUTLINE Introduction & definition Epidemiology Aetiology Classification Diagnosis Investigation Treatment complication

INTRODUCTION & DEFINITION

• Displacement of condylar head completely out of glenoid fossa; cannot be reduced by patient or

• Complete separation of articular surfaces with fixation of condyle in an abnormal position

• Subluxation with excessive abnormal excursion of CH 2 to flaccidity & laxity of capsule or

• Movt of the CH ant to eminence on wide opening of mouth, can be closed again quite easily [Pogrel 1987] – Habitual luxation

INTRODUCTION & DEFINITION

• Recurrent dislocation xsed by CH sliding over the eminence, catching briefly beyond it & then returns to the fossa [Pogrel 1987]

• Genuine (fixed ) luxation• RD assoc. with neurogenic dislocation

increased tone of masticatory muscles

EPIDEMIOLOGY

• Uncommon condition, occurs in young women

• Common in Yemen b/c of habitual qat chewingexcessive loading of TMJ, diagnosis excursive, masticatory movt to habitual rotational movt osteoarthrosis & atrophy of AE & a shallow GF

AETIOLOGY

Extreme mouth opening- dental & ENT TX, under GA,yawning

Trauma- falls, RTATMJ dx – osteoarthrosis, int.joint

derangementHypermobility assoc. with systemic dx e.g

Ehler’s Danlos syndrome, CT disordersMalocclusion- Angles class 2 div 1

AETIOLOGYOcclusal disharmony- long term over-closure

foll. Edentulism, cos of alveolar bone resorptionIll-fitting denturePsychogenic & neurological disorders e.g

Parkinson’s dx, multiple sclerosis,tardive dyskinesia

Neuroleptic drugs e.g phenothiazine; antiemetic e.g metoclopromide (extrapyramidal effects spasms of jaws & facial muscles

Px with congenitally shallow GF or underdeveloped condyle

DIAGNOSIS

• History of factors causing occlusal disharmony, use of neuroleptic drugs, presence of psychogenic or neurological problems, hyperextension of other joints, familial hx of dislocation

• Examination – check for mandibular prognathism, hollow ant to tragus, palpable CH ant to AE, ant open bite, limited mouth opening, pain in or around TMJ

CLASSIFICATION

• Various existsAcute, chronic & recurrent (Rowe& Killey

1968)Anterior (Heslop 1956)- CH moves ant to

AE; antero- lat variant (moris & Hutton (1957)

Posterior (Helmy 1957)- movt of CH posteriorly, assoc base of skull # or ant wall of bony meatus

CLASSIFICATION

Lateral (Attery & Young 1969)-2 types:Type1 –lateral subluxationType2 – complete dislocation with CH forced laterally & superiorly into temporal fossa ( assoc with parasymphyseal #)

Superior (Zeccha 1977)- displacement of CH into middle cranial fossa ( assoc with # of GF)

INVESTIGATION

• Plain radiographs (TMJ views)– transcraniooblique; reverse towne’s; others: PA ,R & L oblique laterals

• Conventional tomograms– orthopantomogram; plain tomograms (lat)

• Computerized tomograms-3D CT scans• MRI• Ultrasound

TREATMENT-nonsurgical & surgical methods

• Non-surgical methodsBimanual reduction with or without anxiolytics &/or LA, GA. Rest jaw 2-3wksSlow elastic traction with Erich pattern arch bars & post bite plane. Rest jaw for 2-3 weeksChemical capsulorrhaphy using Na psylliate (Schultz 1949) 0.5% 1ml soln of Na tetradecyl sulphate(STD) 3X 2-6wk interval causes pericapsular fibrosis which limit CH excursionInjection of autologous blood into the joint

Injection of botulinium toxin type A

SURGICAL METHODS

• Restitution of ligaments & plication of capsule (surgical capsulorrhaphy). Suture line reinforced by turning down a flap of temporal fascia and securing this to both capsule & ligament

• Limitation of forward movt by ligation of condyle- tying a length of fascia lata or mersilene (Georgiade 1965) both to zygomatic arch & around condylar neck

SURGICAL METHODS• Limitation of forward movt by augmentation of

AE using: bone graft from zygomatic arch, mastoid

process, iliac crest & calvariumCalvarial graft- high quality, low incidence of

resorption, minimal donor site morbidity, etc, contain large amount of bone

Allele graft- L-shaped SS pins (Findlay 1964); vitallium mesh (Howe& Kent 1978); titallium miniplates (silastic implants

SURGICAL METHODS

• Down fracturing of zygomatic archMayer (1933)Leclerc & Girard (1943) vertical osteotomyDautrey & Gosserez (1964) post. slanting

osteotomy• Elimination of dislocation by removal of AE

(Myrrhaug (1951)- px continues to dislocate but reduction by px is automatic & painless-condylectomy(Reidel, condylotomy

SURGICAL METHODS

• Prevention of dislocation by removal of activating muscle

Myotomy- lat pterygoid myotomy+/- discectomy

Temporalis myotomy (Laskin)

COMPLICATIONS

• Relapse / recurrence• Facial nerve palsy• Limited mouth opening• Infection• Pseudoarthrosis• Scar formation