TMJ ankylosis

History-

Humphry- 1^st to do mandibular condylectomy for TMJ ankylosis , 1864

Esmarch- pseudo-arthrosis, 1855

Murphy-1914, interpositioning of flap of fat and temporal fascia to maintain pseudoarthrosis.

Pickerill- 1942, cartilage graft for TMJ reconstruction

Stuteville- established- condyle as growth center of mandible.

Ankylosis def.- stiffness of joint as a result of disease process with fibrous or bon fusion across the joint.

TMJ ankylosis- condylar head fuses with glenoid fossa

ANATOMY-

Type of joint- Diarthodial, Ginglymus (hinge), synovial joint

Movement- rotational and translatory

Articulation- mandibular condyle with squamous portion of temporal bone (glenoid fossa)

Blood supply of mandible- inferior alveolar artery and muscle and gingival attachments.

Glenoid fossa –

Anterior articular surface formed by inferior aspect of temporal squama.

Surface – smooth, oval & deeply hollowed out.

Roof of glenoid fossa forms the partition of middle cranial fossa and TMJ.

Fossa is lined by fibrocartilage.

Posterior wall of glenoid fossa – formed by squamo-tympanic fissure – separates it from tympanic plate.

Glenoid fossa is the cranial component of TMJ.

Its limit –

Anteriorly – articular eminence or tubercle.

Posteriorly – a small conical postglenoid tubercle.

(Articular eminence – a small prominence on ZA

Postglenoid tubercle – separates articular surface of fossa laterally from the tympanic plate – tympanic plate separates TMJ from bony part of EAM.)

TMJ articular surface-

Lined with fibrocartilage (avascular fibrous tissue with cartilage)

(TMJ is a synovial joint, but has fibrocartilage lining, while other synovial joint has hyaline cartilage as lining)

Articular disk or meniscus-

It separates TMJ into two spaces-

Upper joint- 1ml volume– extends from glenoid fossa to articular eminence.

Lower joint- 0.5ml volume– begins above the insertion of the lateral pterygoid and then spreads out over the condyle.

Articular disk has two bands for attachments-

Anterior band – is thick and narrow- attaches –

Superiorly –to articular eminence and superior belly of lateral pterygoid

Inferiorly – to condyle (though synovial membrane) along attachment of lateral pterygoid.

Posterior band- it is wide and thick – a Bilamellar structure- highly innervated and vascular.

Upper layer- attaches to – tympanic plates of temporal bone

Lower layer- attaches to – posterior meniscus to neck of condyle.

A third intermediate zone is also described – its thinnest part – gives meniscus flexibility and ability to alter shape under pressure.

Histologically – Disc is meshwork of firmly woven avascular fibrous connective tissue. It is non-innervated.

Disc –

Promotes lubrication

Energy absorption

Joint range of motion

Main shock absorber

Has very little potential for repair after insult

Movements in joint-[HITS]

Hinge movement- Inferior joint space

Translational movement- Superior joint space

Condyle-

Shape- elliptical/oval (broad laterally and narrow medially)

Size- 20mm- medial to lateral (13-25mm)

10mm- AP diameter (6-16mm)

Two condyles of a patient can be asymmetrical.

Surface is mostly convex superiorly (58%) – but can be flat, pointed, angular, round, bulbous.

Articular surface is covered with dense fibrous connective tissue.

This is thickest – anteriorly and superior surface.

The hyaline cartilage is the head of condyle is the growth center of the condylar process.

TMJ capsule –

Thin, Funnel-shaped, Blends with periosteum of mandibular neck

Attachment –

Superiorly –

Anteriorly – to anterior border of articular eminence.

Posteriorly – to lip of squamotympanic fissure & anterior surface of postglenoid process.

To the circumference of the cranial articulating surface

Inferiorly –

To neck of condyle both lateral and medial side.

Capsule is fibrous having a synovial lining on inside.

(Fibrous capsule- attaches to – Zygomatic arch -above & Condyle- below)

Capsule is reinforced- medially and laterally by temporomandibular ligaments.

Ligaments –

Lateral or temporomandibular ligament –

Extends downwards and backwards – from articular eminence to external and posterior side of condylar neck.

Its posterior fibers unites with capsular fibers.

Made of collagenous fibers – have poor ability to stretch à hence maintains integrity and limits movement of TMJ à called ‘check-rein’ ligament

Prevents – Anterior excursion of jaw & Posterior dislocation.

Accessory ligament –

Makes no contribution to joint activity.

These are –

Sphenomandibular

Stylomandibular

Sphenomandibular ligament –

Arising from sphenoid spine and pterygoid fissure

Runs downward and medial to the TMJ

Gets inserted on lingula of mandible.

Its remnant of Meckel’s cartilage

It’s an important landmark – internal maxillary artery and auricotemporal nerve lies b/w it and mandibular neck.

Stylomandibular ligament –

Dense thick band of deep cervical fascia.

Runs from styloid process to mandibular angle.

Blood supply of TMJ-

Superficial temporal vessels and massetric artery branches through sigmoid notch of mandible.

Nerve supply of TMJ –

CN V3 branches –

Largest branch – auricotemporal n – supplies the posterior, medial, lateral part of the joint

Masseteric nerve

Branch of posterior deep temporal nerve – supplies anterior part of joint.

Mean distances-

Outer aspect of zygomatic arch (ZA) to middle meningeal artery – 31mm

MMA to height of glenoid fossa (HGF) – 2.4mm

ZA to carotid artery – 37.5 mm

ZA to IJV – 38.3 mm

Outer aspect of ZA to CN V3 – 35mm

HGF to CN V3 – 9.2mm

Vessels–

Excessive bleeding during TMJ resection – MC related to IMA (internal maxillary artery)

Anterior tympanic artery is intimately related to retroauricular region- supplies posterior part of TMJ.

Retrodiscal venous plexus (pterygoid venous plexus) – venous space in retromandibular space.

Mandible movements and muscles:

Protusion or elevation-

Masseter

Temporalis

Medial pterygoid

Lateral pterygoid- superior portion in elevation

Depressor or retractor-

Geniohyoid

Anterior belly of diagastric – main

Suprahyoid

Sternohyoid

Geniohyoid

Lateral pterygoid – inferior portion in depression

Masseter – elevation and protrusion

Medial pterygoid – protrusion and elevation. U/L movement – mediotrusion

Tempolaris –

Anterior fibers – elevation

Middle fibers – elevation and retrusion

Posterior fibers – retrusion

Lateral pterygoid-

Inferior portion- attaches to neck of condyle à produces movement of the joint – mouth opening and protrusion

Superior portion- attaches to fibrous capsule and meniscus of TMJà stabilizes meniscus during movement of mandible.

At rest condyle articulates with intermediate zone of disc.

Mouth opening – condyle disc complex translates down the articular eminence and then disc rotates posteriorly on condyle.

Superior retrodiscal tissue – limits the forward sliding of disc.

Mouth opening is initiated by – superior head of lateral pterygoid.

Mouth closure – each head glides back and hinges on its disc.

The initial 20-25° of mouth opening is pure Hinge movement. Beyond this condyle translates forwards and rest of the movement occur.

[Depression – Diagastric][Protrusion – Pterygoids][Elevator – Temple & mass – Tempolaris and Masseter][Superior lateral pterygoid- originates from Sphenoid greater wing]

TMJ and its characteristic features –

Articular cartilage – covered by avascular fibrocartilage (not hyaline).
Right and left movements are coupled through mandible
Mandible is stabilized by three functionally linked articulation – 2 TMJs and the dentition. Problem in any of the three will affect mandible movement.
Multiple muscle involved in movement – requires delicate neuromuscular balance
TMJ is the only joint that has rigid endpoint of closure (as a consequence of teeth contacting).
The joint function as a regional adaptive growth center for the growth and development of the mandible and middle third of face (in response to changes in the “functional matrix” of surrounding mastectomy muscle and other sift tissue).

TMJ ankylosis-

Classifications-

Complete/partial

True/pseudo

Bony/fibrous/fibroosseous

Intra-articular/extra-articular

Unilateral/bilateral

Topazian classification:

Type 1

Fibrous adhesion in or around the joint

Restricted condyle gliding

Type 2

Formation of bony bridges between the condyle and glenoid fossa

Type 3

Condylar neck is ankylosed to the fossa completely

CP Sawhney classification-

Type 1	Fibrous adhesions all around the joint making any movement impossible Condylar head- flattened or deformed lies closely approximated to the articular surface.
Type 2	Bony fusion of the head to the outer edge of the articular surface either anteriorly or posteriorly but only to a small area Condylar head- misshaped or flattened but was still distinguishable Deeper to it the articular surface and the articular disk were undamaged
Type 3	Bony block seen to bridge across the ramus of mandible and the zygomatic arch. Condylar head displaced and atrophic lying free or fused Upper articular surface and articular disk of the deeper aspect intact
Type 4	Bony block wide and deep and extends between ramus and upper articular surface, completely replacing the architecture of joint

Type 4 is the MC type.

El- Haki & Metwalli, 2002

A1- fibrous ankylosis with or without bony fusion

A2 – Bony fusion <50%

A3 – Bony fusion >50%

A4 – complete fusion

Etiology-

Consolidation and fibro-osseous restructuring of a hemarthosis.

Hemarthosis itself may have many cause.

Trauma-

Trauma results in ankylosis- 29-100% cases.

Condylar neck fracture is the MC cause.

Factors leading to ankylosis-

Age-Younger age group

Higher osteogenic potential

Rapid repair

Articular capsule not well developed- easier condylar displacement out of fossa- damage to disk

Anatomically different condyle in children—condyle neck is wide and condylar head has blunt anatomyàmore chances of comminuted fracture. More frequent medial displacement of condylar head – more chance of glenoid fossa fracture.

Prolonged period of self- immobilization

Severity of trauma
Site of fracture
Intracapsular fracture à greater risk of ankylosis
Condyle in children poorly tolerates crishing injury directed along its long axis—resulting in burst fracture- severe hemarthosis with multiple osteogenic fragments
Duration of immobilization
Articular disk

Torn or displaced meniscus – provide direct contact b/w a comminuted fracture and glenoid fossa- key factor in developing ankylosis.

Infection-

Septic arthritis- organisms- Neisseria Gonococcus, staphylococcus, streptococcus, hemophilus.

Predisposing factors (for infection):

Blunt trauma, Previous joint disease, Burn wound to region, Systemic/autoimmune disease- RA, Reiter’s, alcohol abuse, hypogammaglobulinemia, Drugs- steroids, immunosuppressant, STDs

Routes:

Hematogenous

Contiguous – from middle ear

Direct- arthroscopy, arthrocentesis, injection in the area, acupuncture

Previous TMJ surgery-

Discoplasty, Dissectomy, High condylar shave procedure, Failed alloplastic material

Orthognathic surgery:

Fibrous ankylosis- following prolonged MMF

Extra-articular ankylosis:

Jacob’s disease- osteochondroma of the coronoid process à subsequent fusion to the base of the zygoma

Ankylosis can occur in non-articular site.

Other causes-

Forceps delivery- a trauma to TMJ.

Congenital –

Fusion of maxilla-mandible (extra-articular)

Intra-articular

Clinical features:

Trismus- is the functional characteristics. The cause of trismus can be many.

Effects-

Direct on mandible
Indirect (secondary effect)

Maxilla (No place to grow because of hypoplastic mandible)

Soft tissue-

Shortened pterygo-masseteric sling

Shortened ligament attaching mandible to skull base

Hypertrophy of – tempolaris, coronoid process, suprahyoid muscle

Narrowing of oropharyngeal airways

Narrowing of space between mandibular angles

Facial features–

Facial deformity is severe if ankylosis occurs before 15yrs of age.

Unilateral ankylosis-

Deviation of chin and mandible towards affected side
U/L vertical deficiency (of ramus) on affected side
Roundness and fullness of face on affected side,
Flatness and elongation of face on opposite side.
Concave mandible that ends up in well-defined “antegonial notch”
Class II angle malocclusion on affected side + U/L posterior cross bite on affected side.
Absent condylar movement on affected side
Occlusion cant with deviation of maxilla and mandibular midline towards affected side.

Bilateral ankylosis-

Retrognathic/micrognathic mandible (which is symmetrical)
Neck chin angle (cervicomental angle) – reduced or almost completely absent.
Bilateral well-defined antegonial notch
Class II malocclusion
Anterior open bite with protrusive upper incisors
Oral opening ↓↓ (<5mm)
Multiple dental caries
Severe malocclusion crowding and impacted tooth
Convex facial profile
Short hypo-mental distance with tight suprahyoid musculature
“Bird-face” deformity (Ande-Gump deformity)- Vogelgesicht
Markedly elongated coronoid process

Obstructive sleep apnea can occur- due to oropharyngeal airways narrowing

Narrowing can occur in-

Cephalocaudal direction- due to shortening of mandibular rami

Transverse – reduced space b/w angle of mandible

Antero-posterior diameter- hypoplastic (↓ed) body.

Key difference b/w intra-articular vs extra-articular

Intra-articular- translational movement – ↓ed or absent

Extra-articular- translational movement- not as limited.

Rotational movement- affected in both

Diagnosis-

History – of trauma or infection
Clinical findings
Radiology

Orthopentagraph (OPG)-

Easy, quick, shows adjacent areas.

Blind area of OPG – angle (blinded by cervical shadow) & symphysis (pharyngeal shadow)

Presence of antegonial notch

Antegonial notch- develops- secondary to contraction of depressor muscle and their action against elevator muscles

Prominent and elongated cornoid process

Shallow sigmoid notch

Cephalometric studies– lateral and antero-paoterior. Required for aesthetic correction.

CT scan-

Very helpful. 3-4 mm cuts are obtained. Evaluates- medial extent of bone mass, Density of bone mass, Thickness of temporal bone

Typical appearance of ankylotic joint is – “mushroom- shaped”

CT scan can also- differentiate any extra-articular contribution to ankylosis.

Minimum 3 slides needed to diagnose

3D-CT –

Allows measurements. Allows subtraction CT

Cone beam CT- CBCT-

Small area of CT. Low radiation dose. Smaller equipment. Small cuts are used 1-2mm.

Provides multiplanar and reformational and 3D images

X-ray-

Fibrous ankylosis- reduced joint space and hazy

Bony ankylosis-

Complete obliteration of joint space
Distorted TMJ anatomy
Deformed condylar head
Complete bony consolidation
Elongation of coronoid process

Sequel of untreated ankylosis-

Facial growth and development affected
Speech impairment
Nutritional impairment
Poor oral hygiene – multiple caries and impacted tooth
Malocclusion
Respiratory distress

Aims and objective of surgery

Restore mouth opening
Restore joint function
Allow for condylar growth
Correct facial profile
Relieve upper airway obstruction
Prevent recurrence

Surgical strategies depend upon-

Age of onset of ankylosis
Extent of ankylosis
U/L or B/L involvement
Associated facial deformity

Surgical technique-

Various technique has been used- but, basically three strategies-

)Condylectomy, 2). Gap arthroplasty, 3). Interpositional arthroplasty.

Surgical approach

Incisions:

Postauricular-

Incision- Behind the external ear in the crease near superior aspect of external pinna and extended to tip of mastoid.

Advantage-good cosmesis

Disadvantage- several

Small exposure- poor access and poor exposure, Stenosis of EAM (external auditory meatus), Infection of external auditory canal, Chondritis, Paraethesia, Deformity of pinna

Endaural approach (Lamport)

Incision- short facial incision with extension into EAM

Begins just above zygomatic arch, extends downwards and backwards into intercartilaginous cleft b/w helix and tragus and then extends inwards along the roof of EAM for approx. 1cm.

Advantage- cosmesis

Disadvantage- Limited access, Meatal stenosis, Chondritis

Submandibular (Risdon’s)-

Incision- 1 cm below and parallel to lower border of mandible going slightly behind

Disadvantage-poor access to condylar head

Used for-approach to neck of condyle and ramus

Post-ramal (Hind) approach-

Indicated for surgery involving condylar neck and ramus

Incision- 1cm behind ramus, extends 1 cm below ear lobe to angle of mandible

Advantage- cosmesis, Excellent visibility and accessibility

Steps-

Incise parotidomasseteric fascia –>Avoid injuring to facial vein and facial n.

Expose posterior border of ramus –>Incise pterygomasseteric sling (PMS) at the angle

Reflect masseter and parotid glands –> Condylar neck is now exposed.

After procedure PMS is re-approximated.

Preauricular (Dingman’s) approach –

Most basic and standard approach to TMJ
Described by Dingman in 1951

Incision – at the junction of the facial skin with the helix of the ear.

Incision from – helix to the upper border of the tragus.

Modifications of preauricular incision –

Blair and Ivy – “Inverted hockey stick” incision ove the zygomatic arch.
Thema – angulated vertical incision.
Al-Kayat & Bramley, 1979 –

Preauricular approach with temporal extension over zygomatic arch considering the main branches of vessels and veins in vicinity.

Facial and main trunk – 1.5cm -2.8 cm below the lower border of EAM.

Temporal branch – 0.8cm – 3.5cm anterior to anterior border of EAM.

Popwich and Crane modification of Al-Kayat & Bramley –

Incision is longer and wider than conventional.

Skin incision is “question mark”. Begins about pinnas length away from ear.

Curves, backwards and downwards well posterior to main branch of temporal vessel. Till it meets upper attachment of ear.

Rest of incision is same.

Advantage –

Decreased facial nerve palsy.

Provision of donor site for temporal fascia

Decreased hemorrhage (avascular plane of dissection)

Improved visibility and easier identification of facial planes.

Reduction and post-op edema and discomfort.

Good cosmesis.

Reduction in operative time.

Avoidance of auricotemporal nerve aneasthesia or paraethesia.

Coronal approach –

Hemicoronoal (U/L incision)

Bicoronal (B/L incision)

Incisions particularly useful for TMJ ankylosis surgery –

1). Dingman’s and its modification, 2). Risdon, 3). Combined approach – Dingman + Risdon, preauricular + coronal (Poswillo, 1974)

Internationally accepted protocols –

Kaban, Perrot, Fischer, 1990

Early surgical intervention
Aggressive resection of bony or fibrous ankylotic segment – gap of at least 1-1.5cm should be created
Ipsilateral coronoidectomy and tempolaris myotomy –
1. Coronoid process cut from the level of sigmoid notch till the anterior border or ramus
2. Tempolaris muscle attachment are severed by carrying out tempolaris myotomy à check intraoral opening – if >35mm à no need for C/L procedure. If opening <35mm àthen C/L coronoidectomy and tempolaris myotomy (this can be done by intraoral incision).
Lining of glenoid fossa region with tempolaris
Reconstruction of ramus with costochondral graft.
Early mobilization and aggressive physiotherapy for at least 6months period post-op.
Regular long term follow up
Cosmetic surgery later on when patient grows.

Coronoidectomy – Important to excise rather than just release à otherwise reankylosis will occur.

Temporalis myofascial flap for Lining of glenoid fossa – based on middle and deep temporal arteries. This flap is a versatile flap for glenoid fossa lining because of –

Robust blood supply
Proximity to TMJ
ability to alter arc of rotation by basing the flap inferiorly or posteriorly
Vague simulation of disc.

El- Sheikh, 1999- Cardinal principles –

Radical resection of ankylosed mass via wide surgical exposure
Release of pterygo-masseteric muscle sling with resection of condylar process
Restoration of vertical ramal height and condylar head by a costochondral graft
Simultaneous correction of jaw bone deformities at the same time as release of ankylosis
Careful selection of patient – who can comply for at least 1 year of follow up.

MC cause of reankylosis –Incomplete removal of the bony or fibrous mass (esp. from medial aspect of joint).

Surgeries –

Gap Arthroplasty (GA) –

Resection –

First described by Abbe, 1880. Recurrence – 14-100%. Minimum extent of width of bone resection – At least 1cm. The procedure causes – gleno-mandibular dysjunction

Laser & arthroscopy –

Ho:YAG laser can be used to debride fibrous ankylosis through arthroscopy creating a pseudo-arthrosis below the mass.

Described by Salins.

Made subcondylar fracture below the ankylosed mass à through post-op physiotherapy creates a pseudo-arthrosis – resulting in mouth opening.

It does not resects the ankylosed mass.

Interpositioning arthroplasty (IA) –

Various grafts has been used for lining the joint after resection of ankylotic mass.

Glovine, 1898- first used the tempolaris myofascial flap (TMF) for orbital reconstruction.

Topazian, 1966 – compared GA and IA in favor of IA.

Other autogenous interposition grafts –

Dermal graft, Masseter muscle graft, Auricular cartilage, Fascia lata, FTG

Alloplastic material –

Proplast/Teflon, Polyethylene, Christensen metallic fossa implant, Silastic sheets, Acrylic marbles

Modification of TMF –

Feinberg & Larsen – described full thickness, pedicled, tempolaris muscle-pericranial flap that includes periosteum along with muscle.

Pogrel Kaban – flap includes fascia alone or with muscle and is inferiorly rotated over the arch into the joint space.

Omura & Fujito – Folded the flap over itself making fascia face both condylar surface and glenoid fossa and thus reducing the functional friction.

Routes of placing TMF –

Tunnel under zygomatic arch (ZA)
Osteomatize the ZA
Thinning of ZA & pass under it
Over the ZA

CCG (costochondral graft)–

Harvested either from 5^th, 6^th rib.

Costochondral junction of rib is chosen along with some length of rib.

Length of total graft will depend on the height of ramus to be restored.

A minimum of 1.5cm of costochondral junction should be included in the graft.

Fixation to lateral aspect of ramus with screws or interosseous wire.

Reconstruction of resected joint –

Goals –

Reestablish joint function
Reestablish vertical height of the ramus and occlusion
Provide growth potential in children

Autogenous grafting –

Costochondral graft (CCG) –

First described by Gillies- 1920

Ware & Brown – promoted its use as potential growth center for the mandibular joint.

CCG is forerunner in autogenous graft choice –

Easily adaptable to the site. Remodels over time. Less donor site morbidity

Infection are rare. Harvested rib generally regenerates.

Anatomical similarity to the mandible condyle. Regenerative and growth potential both at host & donor site. Ease in training and adapting the graft.

Disadvantage –

The cost & time for preparation are considerable

Unpredictable growth pattern – progressive dental midline shift, occlusion changes, chin deviation, enlargement of the graft itself.

CCG should be at least 0.5cm to 2cm to diminish the chance of all graft converting to bone.

A minimum gap of 0.5cm to 1cm should be there b/w graft and glenoid fossa so that free movement is possible.

Other autogenous materials –

Metatarsal, Sternoclavicular joint, Fibula, Iliac crest, Ankylotic mass itself after contouring, Free vascularized whole joint transplant to 2^nd toe, Preserved costal cartilage

Alloplastic materials –

Advantage –

Ability to begin physiotherapy almost immediately after the surgery.

Avoidance of second surgical site

Ability to mimic normal anatomy

Rationale to use alloplastic Vs autograft –

Placing an autogenous tissue into an area where reactive or hypertrophic bone already formed once is not a good idea.

Previously operated joints has compromised vascular bed that will not take up autogenous tissue predictably

Relatively contraindication for allograft use –

Age
Uncontrolled systemic disease eg. DM
Active infection at implant site
Allergy to implant material

Disadvantages –

Cost of device
Material wear & tear
Questionable long term stability
Lack of growth potential

Total joint prosthesis –

CAD-CAM design are useful.

Distraction –

McCarthy first used distraction technique for mandibular lengthening in microsomia. Papageorge & Apostolicis then used this for TMJ ankylosis

Distractor placed along – ascending ramus and inferior border. A reverse corticotomy performed through sigmoid notch.

Simultaneous arthroplasty is done.

Complications –

During anesthesia –

Difficult intubation and risk a/w it.

During surgery –

Hemorrhage – sources –
1. Superficial temporal vessels
2. Transverse facial a
3. Inferior alveolar vessels
4. Internal maxillary vessels
5. Pterygoid plexus of vein
Damage to EAM
Damage to Zygomatic and temporal branch of facial nerve
Damage to Glenoid fossa à leading to perforation of middle cranial fossa
Damage to auricotemporal nerve
Damage to parotid gland
Damage to teeth during jaw opening with stretcher

Post-operative –

Infection
Open bite
Re-ankylosis
Unpredictable growth of costochondral graft
Fracture of graft at costochondral junction à remove cartilage and reshaping the bony part.

Frey’s syndrome –

Pain in auricotemporal region. Gustatory swaeting and occasional erythema. Flushing on the affected side.

Treatment –

Topical agents – Antiperspirants – only for mild symptoms. Anticholinergic – topical glycopyrrolate

Radiation therapy – Dose of 50Gy is used. For very symptomatic patient when other forms of treatment fails.

Surgical procedure –

Skin incision – for localized and small areas

Auricotemporal nerve resection. Tympanic neurectomy. Botulinum toxin A injection

Recurrence of ankylosis –

Causes –

Inadequate gap b/w the fragments
Missing on medial condylar stump and leaving it behind
Fracture of costochondral graft
Loosening of costochondral graft due to inadequate fixation
Inadequate coverage of glenoid fossa
Inadequate post-operative physiotherapy

Two most dreaded complications of TMJ surgery –

Perforation into middle cranial fossa
Severe bleeding from the medial infra-temporal fossa

Dural exposure through glenoid fossa à if Dural tear present à neurosurgical consult

Internal maxillary artery tear à Embolization.

Steps of surgery –

Safe and secure airways or tracheostomy under GA
Gap arthroplasty – with 1.5 – 2.0 cm gap

Tempolaris fascia flap – interposition in the gap

Costochondral graft placed through Risdon’s incision. CCG fixed with two 2mm diameter and 8-10mm length screw.

I/L or C/L coronoidectomy or both if intraoral mouth opening <35mm

Extended sliding genioplasty to correct retruded chin

Consent –

For GA. For Tracheostomy. For CCG

Incision – Skin – as planned (preauricular with hemicoronal extension)

S/C tissue –> incision stops at level of tempolaris fascia

Blunt stripping with back of scalpel sweeping forward, inferiorly up to inferior point of helical attachment.

Root of zygomatic arch palpated – on which a vertical incision is placed down to the bone. Upper limit of incision is carried up to 2 cm above ZA angulated forward at 45°.

Periosteal dissector is used to tunnel the periosteum over the ZA and anteriorly retracted -> exposing the ankylotic mass.

Periosteum over the ramus is bluntly divided to expose the ankylosed mass up to the anterior border of ramus and coronoid if present separately.

Deeper dissection should not be extended below the inferior limit of the bony EAM (to prevent injury to facial nerve).

Ankylotic mass dissected with a cutting burr.

Initially – inferior cut is placed and completed with an osteotome.

Superior cut usually follows cleavage b/w the supposed glenoid fossa and condyle or a horizontal cut.

In dense ankylosis- 1.5 cm osteotomies are performed in layers to avoid arteriovenous anatomy medial to mandible.

Bleeding at this level is due to –

1). Inferior alveolar vessel, 2). Pterygoid plexus, 3). Middle meningeal vessels

And rarely from internal maxillary a. Pressure and cautery will control bleeding.

Mandible is now opened to achieve 35-40 mm mouth opening –> if not achieved –>C/L coronoidectomy

Coronoid, if identified, separately, is usually hypertrophied and is excised through same incision.

Temporoparietal flap – 2 cm in width, dissected about 6 cm superior to ZA. This flap is freed up to 1 cm from ZA (5 x 2 cm flap) and tucked into gap arthroplasty (sutured to remnant of pterygoid muscle or to medial of ramus).

Harvest of CCG –

5^th or 6^th rib. Subperiosteal elevation. 4cm of rib with 5mm of cartilaginous cap.

Chest wound closed in layers. Harvested graft placed lateral to ramus of mandible through Risdon incision.

CCG is secured with two 2mm screws of 8-10mm length.

Advancement genioplasty –

Extended genioplasty is done making bone cut inferior to the mental nerve on either side.

Osteotomy is completed using 2mm burr. Osteomized chin is pulled forward and overlapped on body of mandible anteriorly

Total joint replacement technique –

CAD-CAM generated custom made TMJ condyle and fossa prosthesis.

Endaural (Lamport’s) with hockey stick extension.

Ankylotic mass is exposed.

A Steiger burr is used to perform gap arthroplasty & a condylectomy and ankylotic mass removed.

A sialistic block is then contoured and placed in the gap as a temporary spacer.

IMF is done. Pt is discharged.

CT scan done –> CT scan sent to company for manufacturing prosthesis – after CT, IMF can be removed.

2^nd stage of surgery –

IMF given – Gap arthroplasty exposed à sialistic spacer removed à I/L coronoidectomy done à prosthesis fitted & fixed (with 2mm screw) à IMF released.

Additional procedure if desired range of motion not achieved à C/L coronoidectomy à B/L masseteric myotomy.

F/b post-op radiation –> 10Gy in 5 fraction.

TMJ disorders –

Intra-articular or intrinsic

Extra-articular or extrinsic

Extrinsic factors –

Masticatory muscle disorder –

Protective muscle splinting

MPD (masticatory muscle spasm) syndrome

Myositis

Extrinsic trauma –

Fracture, Traumatic arthritis, Myositis, myospasm, Tendonitis, Myofibrotic contracture

Causes of trismus –

Infection –
1. Acute – odontogenic, or
  1. Around the joint
2. Chronic – tubercular osteomyelitis of ramus/body
Trauma –
1. Fracture ZA – impinging on coronoid
2. Fracture mandible – pain and tenderness or muscel spasm
Inflammation – myositis or muscular atrphy
Myositis ossificans
Tetany
Tetanus
Neurological disorder – epilepsy, brain tumor, bulbar paralysis
Psychosomatic trismus
Drug induced – strychnine
Mechanical blockage – elongation, exostosis, osteoma, osteochondroma
Extrarticular fibrosis
Iatrogenic – hematoma in medial pterygoid (following needle puncture) à leading to fibrosis

Intrinsic factors –

Trauma – dislocation, subluxation, intracapsular fracture, extracapsular fracture, hemarthrosis
Internal disc displacement
Arthritis – OA, RA, JRA, infectious arthritis
Developmental defects –
1. Agenesis/ aplasia of condyle – B/L or U/L
2. Hyperplasia/hypoplasia of condyle
3. Bifid condyle
Ankylosis
Neoplasm

Dislocation, Subluxation, hypermobility of TMJ –

Excursion of condylar head –> normally just under the apices of articular eminence (in some individuals till anterior slope of articular eminence) –> beyond this point is abnormal.

Mandibular dislocation is uncommon in comparison to other joints in body.

Dislocation can be –

Unilateral or Bilateral

Acute (Luxation) or Chronic recurrent (habitual) – subluxation or Long standing

Acute dislocation –

Extrinsic or iatrogenic

Intrinsic or self-inducing forces

Extrinsic or iatrogenic causes –

Blow to chin (while mouth open)

Injudicious use of mouth gag during anesthesia

Excessive pressure on mandible

Intrinsic or self-inducing forces –

Excessive yawning, Vomiting

Singing/blowing wind instruments/laughing loudly

Excessive opening during eating

Hysterical fits

Predisposing factors –

Laxity of ligaments, capsule
Abnormal skeletal form
Previous injuries
Ehler-Danlos Syndrome
Epilepsy
Parkinsons

Clinical factors –

U/L –

Difficulty mastication and swallowing. Profuse drooling of saliva

Deviation of chin to opposite side

Lateral cross and open bite on C/L side

B/L –

Inability to close mouth. Pain, excessive salivation, difficulty speaking

Protruding chin. Anterior open bite

Management –

Assurance. Pain killers. Sedatives.

Pressure and massage of area.

Manipulation – downward force–> and then backward force.

Patient kept on semisolid diet

Long standing dislocation – when dislocation longer than one month.

Chronic recurrent or habitual dislocation or subluxation –

Triad of –

Ligamentous and capsular flaccidity

Eminential erosion

Flattening

Management –

IMF for 3-4 weeks

Sclerosing agents in joint space –> fibrosis

Surgical options –

Capsule tightening procedure
Creation of mechanical obstacle or block
Creation of new muscle balance
Removal of mechanical obstacle
LeClerck’ procedure – ZA fractured to create eminence
Glenotemporal osteotomy – eminence augmentation

Capsule tightening procedure –

Capsulorrhaphy – shortening the capsule and resuture
Placement of vertical incision – in the capsule and drawing it tight by overlapping the edge and suturing
Reinforcement of the joint capsule – by turning down a strip of temporal fascia and suturing to capsule

Creation of mechanical obstacle –

Eminence osteotomy and turning down in front of condylar head – Lindermann
Mayor- eminence grafting – Bone grafting (taken from zygoma) over the eminence to increase the size and height.
Silastic block or Vitallium mesh implant to add to height of eminence
Dautry – zzygomatic arch osteotomy and depressing it in front og condylar head to prevent abnormal forward translation
Findlay – “L-shpaed” pins anchored in the zygomatic process of temporal bone and projecting it anterior to condyle.
Creation of mechanical obstacle – has certain disadvantage – not used frequently.

Direct restrain of condyle – Questionable results

Tempolaris fascia turned down and sutured to lateral surface of articular capsule.
Piece of fascia lata – threaded through hole in the ZA and then second hole in condyle and then tighten it until half of pre-operative opening existed.

Creation of new muscle balance –

After making vertical intraoral incision –

Tempolaris fascia and periosteum divided – from the tip of coronoid to retromolar area.

At and below the coronoid tip – masseter muscle is also partly elevated from the lateral surface of ramus.

Wound then closed horizontally –> fibrosis –> restricts oral opening.

Medial pterygoid myotomy procedure

Removal of mechanical obstacle –

Removal of torn meniscus or meniscectomy – became popular à but lots of side effects.
High condylectomy –
1. Excision of the superior portion of condylar head above the attachment of the lateral pterygoid.
2. This shortened head has now less chance of locking
Eminectomy –
1. Myrhang, 1951
2. Eminectomy allows condylar head to move freely forward and backwards.

Indications –

Recurrent episodes of dislocation
Chronic hypermobility a/e severe pain
Irreversible TMJ pain a/w clicking or grating

Eminectomy –

Simple to perform. Can be performed under local anaethesia.

Joint cavity not opened – avoids injury to meniscus and capsule

Steps –

Skin incision – small horizontal incision over the ZA in the region of articular eminence in front of tragus.

Articular eminence is located ⁓1.5 cm anterior to EAM.

Eminence is then exposed with T-incision, the horizontal portion being over and parallel to ZA and vertical portion extending to the apex of the eminence.

Periosteum reflected to expose entire lateral portion of the eminence.

Series of burr hole then created at the base of eminence in a line parallel to ZA

Burr is directed downwards @ 10° to horizontal plane.

These burrs are then connected with fissure burr.

Eminence is then sectioned and separated.

Base is then smoothened.

(Foramen spinosum is just mesial to articular eminence. It contains MMA (middle meningeal artery) – may be source of major hemorrhage after eminectomy).

Area is thoroughly irrigated – wound closed in layers.

Pressure bandage given for 48-72 hrs.