Pooja kaloniya

48/2009

TEMPOROMANDIBULAR JOINT

THE TEMPOROMANDIBULAR JOINT IS ALSO KNOWN AS THE CRANIOMANDIBULAR JOINT or BILATERAL DIARTHROIDIAL.

IT IS THE ARTICULATION BETWEEN THE SQUAMOUS PART OF THE TEMPORAL BONE AND THE HEAD OF THE MANDIBULAR CONDYLE.

IT IS ALSO CONSIDERED AS COMPLEX JOINT BECAUSE IT INVOLVES TWO SEPARTE SYNOVIAL JOINT, IN WHICH THERE IS A PRESENCE OF INTRACAPSULAR DISC OR MENISCUS.

ANATOMY

THE TMJ ARTICULATION CONSIST OF:GLENOID FOSSAARTICULAR

EMINENCECONDLYESEPARATING DISCJOINT FIBROUS

CAPSULEEXTRACAPSULAR

LIGAMENTS

ARTICULATORY SYSTEMCOMPRISES OF

Temporomandibular joint

Masticatory and accessory muscles

Occlusion of teeth

The function is governed by sensory and motor branches of the third division of trigeminal nerve.

MANDIBULAR FOSSA(GLENOID) IT HAS AN ANTERIOR ARTICULAR AREA BY THE

INFERIOR ASPECT OF TEMPORAL SQUAMA. THE FOSSA IS LINED BY A DENSE AVASCULAR

FIBROCARTILAGE.

ARTICULAR EMINENCE IT SEPARATES THE ARTICULAR SURFACE OF THE

FOSSA LATERALLY FROM THE TYMPANIC PLATE. THE EMINENCE IS COVERED BY DENSE, COMPCT,

FIBROUS TISSUE THAT CONSISTS PRIMARILY OF COLLEGEN WITH AFEW FINE ELASTIC FIBERS

TMJ CAPSULE IT IS A THIN SLEEVE OF FIBROUS TISSUE INVESTING

THE JOINT COMPLETY IT IS A FUNNEL SHAPED CAPSULE,WHICH BLENDS

WITH THE PERIOSTEUM OF THE MANDIBULAR NECK AND ENVELOPS THE MENISCUS

IT REINFORCE THE TMJ CAPSULE IT EXTENDS DOWNWARD & BACKWARD FROM THE

ARTICULAR EMINENCE TO THE EXTERNAL AND POSTERIOR SIDE OF THE CONDYLAR NECK

ITS POSTERIOR FIBER ARE UNITED WITH THE CAPSULAR FIBERS

THIS LIGAMENT IS COMPOSED OF COLLAGENOUS FIBERS THAT HAVE SEPIFIC LENGTH AND POOR ABILITY TO STRETCH, HENCE IT MAINTAINS THE INTEGRITY AND LIMITS THE MOVEMENT OF TMJ

IT MAINLY LIMITS THE ANTERIOR EXCURSION OF THE JAW AS WELLAS PREVENTS POSTERIOR DISLOCATON , ALSO CALLED CHECK LIGAMENT.

TEMPOROMANDIBULAR LIGAMENTS

SPHENOMANDIBULAR LIGAMENT A FLAT BAND

ARISING FROM THE APHENOID SPINE AND PETROTYMPANIC FISSURE, RUNS DOWNWARDS AND MEDIAL TO THE TMJ

INTERNAL MAXILLARY ARTERY AND AURICULOTEMPORAL NERVE LIES B/W IT AND MANDIBULAR NECK

STYLOMANDIBULAR LIGAMENTIT IS DENCE THICK BAND OF THE DEEP CERVICIVAL FASIA EXTENDING FROM THE STYLOID PROCESS TO THE MANDIBULAR ANGLE.

THE MENISCUS DIVIDES THE TWO ARTICULAR SPACE INTO TWO COMPARTMENT LOWER OR INFERIOR COMPARTMENT- condylodiscal

complex b/w the condyle and the disc UPPER OR SUPERIOR COMPARTMENT – b/w disc and the

glenoid fossa.The disc is biconcave in the sagital section.The superior surface is concavoconvex to match the

anatomy of the glenoid fossa.The inferior surface is concave to fit over condylar headThe disc blends medially and laterally with the capsule,

which is attached to the medial and lateral poles of the condyle.

Anteriorly the disc is attached to the articular eminence above & to the articular margin of the condyle below.

Posteriorly disc is attached to the posterior wall of glenoid fossa

ARTIULAR DISC/ MENISCUS

The disc is a meshwork of firmly woven avascular fibrous connective tissue & it is also noninnervated with possible exceptions around its periphery.

These collagen fibers impart flexibility to the disc.

The disc is designed to transmit the forces generated through the condyle to the articular eminence.

It promotes lubrication energy absorption and joint range of motion. It acts as a main shock absorber enabling the articulating bones to move against each other with minimum friction and heat production.

Disc has Avery little potential for repair after inult.

Lateral aspect is supplied by superfical temporal branch of the external caroid artery.

Rich vascular supply to the deep and posterior aspect of retrodiscal capsular part by deep auricular, posterior auricular & masseteric branches of the internal maxillary artery

Vascular supply to the lateral pterygoid muscle also supplies to the head of the condyle by penetration of numerous nutrient foramina vessels

Blood supply

THE MANDIBULAR NERVE, THE THIRD DIVISION OF THE FIFTH CRANIAL NERVE INNERVATES THE JAW JOINTS:-The largest is the

auriculotemporal nerve which supplies the posterior, medial and lateral part of the joint

Masseteric nerveA branch from the

posterior deep temporal nerve, supply the anterior parts of the joint

Nerve supply

The movements of tmj are manifold. It is ginglimus diarthroidai type of joint, as it sis capable of rotating around more than one axis and is capable of translatory movement.

MUSCLE FUNCTION- The functions of the muscles of mastication in jaw movement are coordinated and balanced by normal muscle tone.

The muscle of mastication (medial and lateral pterigoid,masseter, buccinator, mylohyoid, temporalis & anterior belly of the digastric) are assisted by the suprahyoid and digastric muscle.

MOVEMENTS

JAW OPENING It is dominated by daigastric muscle contraction, which depress the body of the mandible. This action is assisted by the suprahyoid, sternohyoid and geniohyoid muscles.

JAW CLOSURE It is accomplished by the simultaneous contraction of the masseter, medial pterigoid muscles.

PROTRUSIVE MOVEMENT It requires equal simultaneous contracture of lateral and medial pterygoid muscle.

RETRUSION It is brought about by posterior fibers of temporalis muscles, assisted by middle and deep parts of the masseter, digastric and geniohyoid muscles.

LATERAL MOVEMENT These are carried out by unilateral contracture of medial and lateral pterygoid of each side acting alternatively.

TEMPOROMANDIBULAR JOINT DISORDERS CLASSIFICATION

Intra –articular origin or intrinsic disorderExtra –articular origin or extrinsic disorder

MASTICATORY MUSCLE DISORDERProtective muscle splintingMasticatory muscle inflamationMasticatory muscle spasm

PROBLEMS DAT RESULT FROM EXTRINSIC TRAUMATraumatic arthritisFractureInternal disc derangementTendonitisContracture of elevator muscle

DISORDER DUE TO EXTRINSIC FACTORS

TRAUMADislocation, subluxationHaemarthrosisIntracapsular fracture, extracapsular fracture

INTERNAL DISC DISPLACEMENTAnterior disc displacement with reductionAnterior disc displacement without reduction

ARTHRITISOsteoarthritisRheumatoid arthritisJuvenile rheumatoid arthritisInfectious arthritis

DISORDER DUE TO INTRINSIC FACTORS

DEVELOPMENTAL DEFECTSCondylar agenesis or aplasia-

unilateral/bilateral Bifid condyle Condylar hypoplasiaCondylar hyperplasia

ANKYLOSISNEOPLASM

Benign tumoursMalignant tumours

Surgical access to the tmj is an exacting procedure.

Tmj has got close proximity to the main trunk of the facial nerve with its branches in the temporal and

facial areas

It has also got close proximity to the auriculotemporal nerve and the abundant vascular

supply

SURGICAL APPROACHES TO MANDIBULAR

CONDYLE AND ITS NECK

ADVANTAGESUniform predictability of anatomic exposure &

avoidance of a salivary fistula.Negligible hemorrageNo distortion of anatomic landmarks

DISADVANTAGESInfection involving the external auditory canalParesthesis of the external pinnaSmall surgical exposure with poor access and

visibility

POSTAURICULAR APPROACH

POST/ RETRO AURICULAR

ADVANTAGESExcellent cosmesisExcellent lateral and posterior exposure with

intermediate anterior exposureDIADVANTAGES

Limited accessPossibility of meatal stenosis

ENDAURAL APPROACH

ADVANTAGESExcellent cosmesisExcellent visibility and accessibility

DISADVANTAGESClose proximity of the posterior facial vein and

trunk of the facial nerveProximity of the posterior border of the parotid

glandIdeal approach to the condyle neck and ramus

POSTRAMAL(HIND) APPROACH

ADVANTAGESInconspicuous location of the incisionStandard approach to the TMJ

DISADVANTAGESThe dissection follows a route through an area

which is rice in nerve and vascular supply.

BLAIR AND IVY INCISIONTHOMA;S ANGULATED INCISIONAL- KAYAT AND BRAMLEY

PREAURICULAR APPROACH

PREAURICULAR INCISION

Blair’s Inverted Hockey Stick

Incision

Thoma’s Angulated Incision

Dingman’s Incision

Popowich & Crane Incision

PREAURICULAR INCISION

ADVANTAGES OF POPWICH’S MODIFICATIONREDUCTION IN INCIDENCE OF

FACIAL NERVE PALSYDECEASED HAEMORRHAGEIMPROVED VISIBILITY GOOD COSMETIC RESULTSREDUCTION IN TOTAL OPERATION

TIMEAVOIDANCE OF

AURICULOTEMPORAL NERVE ANAESTHESIA

REDUCTION IN POSTOPERATIVE OEDEMA AND DISCOMFORT

POPOWICH INCISION

MANAGEMENT

ANKYLOSIS OF TMJ

It is a greek terminology meaning “STIFF JOINT”

The jaw function gets affected because of immobility of the joint.

Hypomobility to immobility of the joint can lead to inability to open the mouth from partial to complete.

Onset is usually seen before the age of 10 years.

WHAT IS ANKYLOSIS ?

FALSE ANKYLOSIS OR TRUE ANKYLOSISEXTRA –ARTICULAR OR INTRA –ARTICULAR FIBROUS OR BONYUNILATERAL OR BILATERALPARTIAL OR COMPLETE

CLASSIFICATION OF ANKYLOSIS

Trauma- At birth (with forceps)- Haemarthrosis- Blow to the chin (causing

haemarthrosis)- Condylar fracture- congenital

Infections and Inflammatory- Rheumatoid Arthritis- Septic arthritis- Otitis media- Mastoditis- Parotitis- Osteomyelitis- Osteoarthritis- Tonsillitis

Systemic disease- Small pox- Ankylosing spondylitis- Syphilis- Typhoid fever- Scarlet fever

Others- Malignancies- Post radiology- Post surgery- Prolonged trismus

Rare causes- Polyarthritis- measles

AETIOPATHOLOGY

TRAUMA

Extravasation of blood into the joint space

haemarthrosis

Calcificatiion and obliteration of the joint space

Intra-capsular ankylosis Extra-capsular ankylosis

PATHOPHYSIOLOGY

DIAGNOSIS

It depends more upon clinical examination, rather than the diagnostic test.

Restricted or nil oral opening is seen.Patient will complain of difficulty in mastication.Protrusive movements are not possible on the

involved side.Partial mobility or complete immobility of the

condyle is readily noticed.Pain is totally absentIn young patient a nature of facial deformity will

help to differentiate b/w unilateral and bilateral involvement

CLINICAL MANISFESTATIONS

IT VARY ACCORDING TO:Severity of ankylosisTime of onset of ankylosisDuration

EARLY JOINT INVOLVEMENT- less than 15 years: severe facial deformity and loss of function

LATER JOINT INVOLVEMENT- after the age of 15years: facial deformity marginal or nil but functional loss is severe.

Those patient in whom ankylosis develops after full growth completion have no facial deformity.

Obvious facial asymmetryDeviation of the mandible and chin on the affected sideThe chin is receded with hypoplastic mandible on the

affected sideThe appearance of the flatness and elongaltion on the

unaffected sideThe lower border of the mandible onthe affected side hass

a concavity that ends in a well- defined antegonial notchIn unilateral ankylosis some amount of oral opening may

be possible. Interincial opening will vary depending on whether it is fibrous or bony ankylosis

Cross bite may be seenClassic angles malocclusion on the affected side plus

unilateral posterior cross bite on the ipsilateral side seenCondylar movements are absent on the affected side

UNILATERAL ANKYLOSIS

Inability to open the mouth progresses by gradual decrease in interincisal opening. The mandible is symmetrical but micrognathic.The patient develops typical 'bird face' deformity with receding chin.

The neck chin angle may be reduced or almost completely absent

Antegonial notch is well defined bilaterallyClassii malocclusion can be noticedUpper incisors are often protrusive with anterior open

bite.Maxilla may be narrowOral opening will be less than 5mm or many times there is

nil oral openingMultiple carious teeth with bad periodontal health can be

seenSevere malocclusion, crowding can be seen and many

impacted teeth may be found on the x-rays.

BILATERAL ANKYLOSIS

History of trauma, infection, etc Clinical finding Radiographic finding- are important in arriving at a final

daignosis Orthopantomograph- will show both the joints picture

which can be compared in unilateral cases. Lateral oblique view- will give anteroposterior

dimension of the condylar mass. Elongation of coronoid process can be seen.

Cephalometric radiograph- is taken to evaluate the associated skeletal deformities

Posteroanterior radiograph- will reveal the medio lateral extent of the bony mass. It will also highlight the asymmetry in unilateral cases

CT scan- very helpful guide for surgery. Relation to the medial cranial fossa, the anteroposterior width, mediolateral depth can be assessed. Any presence of fractured condylar head on the medial aspect of ramus can be located

DIAGNOSIS

FIBROUS ANKYLOSISReduced JOINT SPACE AND HAZY

APPEARANCE CAN BE SEEN.But, still the normal anatomy of the head and

glenoid fossa can be appreciated.BONY ANKYLOSIS

Complete OBLITERATION OF JOINT SPACE NORMAL TMJ ANATOMY IS DISTORTED.

Deformed condylar head or complete bony consolidation replacing the joint space can be seen.

Elongation of the coronoid process onthe side of hypomobility will be seen.

RADIOGRAPHIC FINDINGS

Normal facial growth and development affected.

Speech impairment.Nutritional impairment.Respiratory distress, especially in bilateral

involvement with severe micrognathia.Malocclusion.Poor oral hygiene.Multiple carious and impacted teeth.

SEQELAE OF UNTREATED ANKYLOSIS

Release of ankylosed mass and creation of a gap to mobilize the joint

Creation of a functional jointTo improve patient's nutritionTo improve patient's oral hygieneTo carry out necessary dental treatmentTo 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.

AIMS AND OBJECTIVE OF SURGERY

Early surgical interventionAggressive resection: a gap of atleast 1- 1.5cm

should be created. Special attention should be given to fusion on the medial of the ramus.

Ipsilateral coronoidectomy and tempralis myotomy: in most of these cases there is always association of elongated coronoid process. After carrying out gap arthoplasty. The coronoidectomy on the same side should be carried out either separately or in combination with the gap arthroplasy cut from the same etraoral incision.

The Internationally Accepted Protocol For The Management Of Tmj Ankylosis By Kaban, Perrot And Fisher In 1990

Lining of the glenoid fossa region with temporalis fascia

Reconstruction of the ramus with a costochondral graft.

Early mobilization and aggressive physiotherapy for the period of at least six months postoperatively

Regular long-term follow-upTo carry to cosmetic Surgery at the later date

when the growth of the patient is completedRelease of the jaw movements is quite

dramatic, upon competion of coronoid rather than release it and allow it to be pulled up superior process is removed, there is potential for reankylosis after reattachment.

Most surgical procedures can be done through a preauricular incision alone.

The popwich's incision is chosen for its obvious advantages

Whenever required additional submandibular incision can be used for fixation of the graft.

 I : condylectomyII : gap arthroplastyIII : interpositional arthroplasty

SURGICAL TECHNIQUES

It is advocated in cases of fibrous ankylosis, where joint space is obliterted with deposition of fibrous bands , but there is not much deformity of the condylar head.

 Radiologically and clinically after surgical exposure one can see the demarcation between the roof of the glenoid fossa and the head of the condyle.

The procedure can be done via preauricular incision

The unilateral condylectomy tends to cause devation of the mandibule towards the operated side on oral opening and if bilateral, anterior open bite will be caused as a result of the loss of the height in the vertical rami.

CONDYLECTOMY

Therefore. When the site of the fused joint is mobilized via condylectomy. Then after recontouring by arthroplasty, an alloplastic material can be used to maintain the joint space, satisfactory occlusion and joint movement.

In the extensive bony ankylosis, a broad,thick area of bone deposition obliterates the entire joint, sigmoid notch and coronoid process

Identification of the previous joint structure is impossible and mobilization at level of joint become difficult

 In this operation the level of section is below that previous joint space

The section consist of two horizontal osteotomy cuts and removal of a bony wedge for creation of a gap between the roof of the glenoid fossa and ramus.

Minimum gap of 1cm is recommended to pervent reankylosis

GAP ARTHROPLASTY

It involves the creation of gap , but in addition a barrier is inserted between the cut bony surfaces to minimize the risk of recurrence and to maintain the vertical height of the ramus

INTERPOSITIONAL ARTHROPLASTY

Tamporalis fascia along with a varying thickness of temporalis muscle may be harvested as an axial flap based on the middle and deep temporal arteries and veins

The dependable blood supply, the proximity to the tmj and the ability to alter the arc of rotation by basing the flap inferiorly or posteriorly, makes this a versitile flap for lining the glenoid fossa.

It is used as an interpositional material after release of ankylosis of tmj.

LINING OF THE GLENOID FOSSA SIDE BY TEMPORALIS MYOFAICIAL FLAP

Basic 3 goals1. To replicate structurally normal joint

anatomy2. To provide functional articulation3. To establish an area , where adaptive growth

can occurs.

INTERPOSITION ARTHROPLASTY USING AUTOGENOUS COSTOCHONDRAL GRAFT

Costochondral graft is harvested through the infra-mammary incision

Either 5th, 6th, or 7th rib is harvested.Costochondral junction of rib is chosen along

with some amount of length of the rib.The length of the total graft will depend on the

height of ramus to be restoredMinimum of 1.5cm of costochondral junction

should be included in the graftThe graft should be fixed on the lateral aspect of

the rammus with the screws.A minimum gap of 0.5 - 1 cm should be kept

between the graft and the glenoid fossa side, so that free movement is possible without any friction

Increased operating timeAdditional surgical siteDonor site morbidityGraft over growthPossible potential for reankylosis

Disadvantages

DURING ANAESTHESIAAs the patient cannot open the mouth, awake

blind intubation has to be done, where patients cooperation is required, which is very difficult to obtain from younger group of patients

Because of small mandible and altered position of the larynx .intubation poses a problem

Aspiration of blood clot tooth or foreign body during extubation as throat cannot be packed prior to surgery

Danger of falling back of tongue and obstructing airway is always there after extubation

COMPLICATIONS DURING TMJ ANKYLOSIS SURGERY

DURING SURGERYHaemorrage due to damage to any of the

superficial temporal vessels, transverse facial artery, inferior alveolar vessel and internal maxillary vessels, pterygoid plexus of veins

Damage to external auditory meatusDamage to zygomatic and temporal branch of

facial nerveDamage to glenoid fossa and thus leading entry

into middle cranial fossaDamage to auriculotemporal nerveDamage to parotid glandDamage to the teeth during opening of the jaws

with jaw stretcherDURING POSTOPERATIVE FOLLOW-UP

InfectionOpen biteRecurrence of ankylosis

An inadequate gap created between the fragments

Missing on the medial condylar stump and leaving it behind

Fracture of the costochondral graftLoosening of the costochondral graft due to

inadequate fixation to the ramusInadequate coverage of the glenoid fossa surfaceInadequate postoperative physiotherapyHigher osteogenic potential and periosteal

osteogenic power may be responsible for high rate of recurrence in children

RECURRENCE OF TMJ ANKYLOSIS

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