Recurrent Tmj Dislocation 4m243n

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 chewingexcessive 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, RTA TMJ dx – osteoarthrosis, int.t derangement Hypermobility assoc. with systemic dx e.g Ehler’s Danlos syndrome, CT disorders Malocclusion- Angles class 2 div 1

AETIOLOGY Occlusal disharmony- long term over-closure foll. Edentulism, cos of alveolar bone resorption Ill-fitting denture Psychogenic & 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 ts, 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 exists Acute, 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 subluxation Type2 – 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 methods Bimanual reduction with or without anxiolytics &/or LA, GA. Rest jaw 2-3wks Slow elastic traction with Erich pattern arch bars & post bite plane. Rest jaw for 2-3 weeks Chemical capsulorrhaphy using Na psylliate (Schultz 1949) 0.5% 1ml soln of Na tetradecyl sulphate(STD) 3X 26wk interval  causes pericapsular fibrosis which limit CH excursion Injection of autologous blood into the t

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 & calvarium Calvarial 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 arch  Mayer (1933)  Leclerc & Girard (1943) vertical osteotomy  Dautrey & Gosserez (1964) post. slanting osteotomy • Elimination of dislocation by removal of AE (Myrrhaug (1951)- px continues to dislocate but reduction by px is automatic & painlesscondylectomy(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