TMJ Anatomy

Temporomandibular Joint

Temporomandibular Dysfunction

Chief ComplaintSigns and symptoms

PainTMJ

MusclesHeadache or earache

Altered jaw mechanicsLimited range of motion

Joint noiseClickingCrepitus

History of Present Illness

Onset

Duration

Extenuating circumstances

Clinical Examination

Myofascial palpation

MIO and symmetry

Excursion and protrusion

Occlusion

Palpation and auscultation of joint

TMJ AnatomyGinglymoarthroidal joint

- Ginglymoid: hinge movement- Rotation of condyle on disk in

inferior joint space

- Multiple axis translation between condyle-disk complex and

temporal bone

- Load bearing condyles function as fulcrum point for class III lever

- Functional unit requires response in contralateral joint with every

movement on ipsilateral side- Compound synovial joint

TMJ AnatomyGlenoid fossa

- Concave structure lined with thin layer of fibrocartilage (absence of loading)

- Petrotympanic fissure posterior boundaryAttachment of capsule limits boundary of posterior

superior recess of joint cavityChorda tympani nerve courses in medial aspect of

fissure

- Temporal bone (1 – 2 mm thick) separates middle cranial fossa from TMJ

- Spine of sphenoid, sphenomandibular ligament and middle meningeal artery (foramen spinosum) positioned medially

TMJ AnatomyArticular eminence

- Prominent convexity covered with dense, compact connective tissue

- Subjected to loading during function

- Anterior bilaminar zone inserts on

ascending slope of eminence

- Limitation of anterior superior recess of joint

TMJ AnatomyCondyle

- Broad mediolaterally twice that of anteroposterior dimension

- Condylar axis along tubercles runs in posteromedial direction forming obtuse angle

- Articular surface covered with thick layer of fibrocartilage

- Remodeling with excessive loading

Articular Disk- Biconcave avascular fibrocartilage (collagen)- Posterior, intermediate and anterior bands- Divides joint into two compartments allowing

complex movements of rotation and translation

- Functions in load adaptation and fluid distribution

- Attachments:Medial and Lateral: condylar poles

Anterior: capsule and superior head of lateral pterygoid

Posterior: bilaminar zone (retrodiskal tissue)

TMJ AnatomyJoint Spaces

- Superior joint space

Translation between condyle-disk complex and articular eminence

Volume: 1.2 cc

- Inferior joint space

Rotation of condyle

on disk

Volume: 0.9 cc

TMJ Anatomy

Facial nerve- Temporal branch

crosses zygomatic arch: mean 2.0 cm (0.8 – 3.5 cm) anterior to concavity of EAM

- Bifurcation of facial trunk 1.5 – 2.8 cm inferior to bony external auditory canal

-

TMJ Imaging

Arthrography- Position, shape and integrity of disk - Therapeutic dilation

- Accurate in demonstrating displacement - Extinct?

TMJ ImagingCT scan

- Indicated in complex trauma or advanced joint pathology

- Depicts osseous structures with poor disk visualization

- Direct sagittal imaging

- Reformat in different planes and 3D reconstruction

TMJ Imaging

- Direct multiplanar examination of structures

- Delineation of disk morphology and position

- Evaluation of joint inflammation and effusion

- Non-invasive, no ionizing radiation

- Titanium plates and dental implants not prohibitive

Magnetic Resonance Imaging

TMJ ImagingT1 – weighted images- 300 – 600 msec- Morphology (contours,

displacement, deformity)

- Fat highlighted- Bone: cortex – black

T2 – weighted images- 2000 msec- Pathology (effusions, avascular necrosis, etc.)- Water highlighted

TMJ Imaging

Disk displacement (arrows) in sagittal and coronal planes illustrated by MRI

TMJ PathophysiologyEtiology of TMJ disorders

multifactorialDirect mechanical injury- Excessive load can lead to physical disruption of

molecules generating free radicals- Free radical damaging to tissue- Superoxide anion implicated in degradation of

hyaluronic acid

Osteoarthritis- Result of chrondrocyte controlled anabolic and

catabolic processes- Progressive degradation of matrix with accumulation

of inflammatory factors- Initial morphologic changes are subclinical

TMJ PathophysiologyOsteoarthritis

Early Stage- Characterized by increased degradation

exceeding synthesis- Increased metabolic activity in chondrocytes

with disorganized proliferation

Clinical features

Pain

Limitation of opening

Arthroscopic findings

Edematous articular cartilage

Superficial fibrillation

Synovitis

Adhesions


Intermediate Stage- Increased degradation exceeds limited

synthesis- Progressive degradation and loss of structure

Clinical features

Pain

Limitation of opening

Joint noise


Advanced fibrillation

Thinning of articular cartilage

Disk displacement

Joint stenosis


Late Stage- Degradation of articular surfaces


Severe fibrillation

Denudation

Villonodular synovitis

Disk displacement

Disk degeneration or perforation

Joint stenosis

Clinical features

Pain

Limitation of joint movement

Crepitance

Residual Osteoarthritis may have decreased symptoms and

improved motion

TMJ Disorders

Conservative Management

Splint Therapy- Nonsurgical phase III

- Maintenance of occlusal scheme with flat plane acrylic splint to decrease

parafunctional habits and load

- Stabilize TMJ, redistributing occlusal forces,

protecting dentition, decreasing bruxism and reducing pain

Undisputed applications for TMJ Surgery

• Ankylosis

• Growth disorders

• Recurrent subluxation

• Infections

• Neoplasms

• These make up the minority of TMJ cases

Relative Indications for TMJ Surgery

• TMD is refractory to appropriate non-surgical therapies

• TMJ is the source of pain and/or dysfunction that results ina significant impairment to the patient in day to day acitivity– Pain localized to the TMJ

– Pain on loading of the TMJ– Pain on movement in the TMJ– Mechainical interferences in the TMJ

Surgical Procedures for Temporomandibular disorders

• Arthrocentesis and lavage

• Arthroscopy

• Arthrotomy

• Modified condylotomy

• Adjunctive procedures for TMJ– Botox– Coronoidectomy

Arthrocentesis- Minimally invasive, simplest TMJ intervention follows conservative management- Local vs. conscious sedation- Lavage, lysis, manipulation, injection of meds

ArthrocentesisBenefits

- Reduction of joint friction, release of fine adhesions, re-establish range of motion

- Evacuation of debris, chemical mediators of pain and

inflammation- Therapeutic, low

morbidity, cost effective

Indications-Localized joint pain, acute limitation of motion (interincisal and excursion), inflammatory

conditions

- Limited improvement with medical management

Arthrocentesis Technique- Auriculotemporal nerve block

- Needle positioned at 10-2 point anterior to tragus

- Identify arch and periosteum

- Superior joint space confirmed with vacuum after insufflation, return of joint fluid, mandible motion

- Additional port placed immediately anterior

- Lavage joint with 100-200 cc

- Steroid and anesthetic infiltrated

Arthrocentesis Results- Significant reduction in pain and increased

opening in >70% of patients

- Nitzan, et al: 91.8% success rate in treatment of severe, limited range of motion (1991)

- Hosaka, et al: “Outcome of Arthrocentesis for TMJ with Closed Lock at 3-year follow

up.”70% success rate at 3 months and 78.9% at 3 years

- Goudot, et al: 79% improvement in pain; arthroscopy 52% (2000)Functional improvement more significant with

arthroscopy (9.6 ± 5.8mm) vs. 4.3 ± 4.4mm

Arthroscopy

- TMJ arthroscopy first reported in literature (Ohnishi, 1975)

- Arthroscopic anatomy, diagnosis and treatment of locking TMJ (Murakami, 1984)

- Holmlund and Hellsing describe identifiable and repeatable puncture sites (1985)

- McCain and Sanders pioneers in arthroscopic surgical techniques (1985)

Historical Perspective

Arthroscopy Technique

Preoperative Preparation- General anesthesia - nasotracheal intubation

- Exam under anesthesia (palpation)- Elimination of muscle influence permits

evaluation of joint function- Bacitracin impregnated

cotton pellet placed in external auditory meatus

- Prep and sterile Quinn drape

Arthroscopy TechniqueSuperior Joint Space Insufflation

- 18-gauge needle positioned at 10-2 point anterosuperiorly paralleling ear canal

- Contact lateral rim of glenoid fossa, needle guided around rim inferiorly, medial insertion to enter joint space

- Balloon joint space with ≈ 3-5 cc normal saline; aids trocar placement (plunger rebound indicates correct position

and adequate insufflation)

Arthroscopy TechniqueTrocar placement- Cannula and trocar positioned with anterior and

superior vector on lateral zygomatic arch in region of posterior slope of articular eminence

- Tip advanced to bone edge, periosteum scored and inferiorly directed for incising capsule

- Stepping off bone ledge rotating through capsule and advancing into superior joint space

- Puncture into posterior recess entering joint in single pass (multiple lacerations increase postoperative inflammation and morbidity)



- Arthroscope advanced through lateral recess to visualize anterior aspect of articular eminence, anterior disk and anterodiskal tissue- Access to anterior recess provides visualization for

placement of second working port

Arthroscopy TechniqueTriangulation

Working port placed after stab incision at 25-10 point (minimum of 15 mm separation between ports)

Second portal in eminence region placed under direct visualization allows instrumentation of joint contents

Arthroscopy TechniqueInstrumentation

- Blunt trocar, radiofrequencyprobe, motorized shaver, and/or laser utilized

- Treatment of adhesions, pathology, internal derangements and removal of tissues

- Depth roughly 20 – 25 mm from skin to center of joint

- Lavage of joint with irrigation expands joint space, allows visualization during instrumentation and flushes irritants (inflammatory and pain mediators)

Arthroscopic Anatomy

Medial synovial drape- First area examined with

classic gray-white translucent lining

- Vertically running stria provide orientation

- Vascular proliferation during inflammatory states

Arthroscopic AnatomyPterygoid shadow- Purple hue related to presence of pterygoid

muscle beneath thin synovial lining- Medial trough leads from medial synovial

drape anteriorly to pterygoid shadow- Marked erythema in pathologic states

Arthroscopic AnatomyRetrodiskal synovium- Taut tissue when condyle in normal position

and bunched with condylar seating- Oblique protuberance (fibroelastic band)

evident when condyle translated anteriorly

- Hypervascularity and synovial redundancy apparent during inflammatory states- Lateral recess difficult to

inspect secondary to angle of trocar

placement

Arthroscopic AnatomyGlenoid fossa and posterior slope of

eminence- Arthroscope positioned immediately inside of capsule- Fibrocartilage distinctly white and reflective

- Striations in fibrocartilage on posterior slope diminish on thin layer covering glenoid fossa

- Iatrogenic trauma to fibrocartilage may result in degenerative erosions

Arthroscopic AnatomyArticular Disk

- Smooth surface with no dimpling or vascularity

- Retrodiskal flexure at junction of synovium and posterior band

- Manipulation of mandible to evaluate position and

function of disk

- Redundant tissue often evident with displacement

Arthroscopic AnatomyIntermediate zone- Space between posterior slope of eminence

and articular disk- Normal anatomy described as white

fibrocartilage on smooth white disk contour

- Condylar position and displacement of disk alter zone

- Maneuvering through intermediate zone allows visualization of anterior recess

Arthroscopic AnatomyAnterior recess

Arthroscopic ManeuversLysis and Lavage- Most conservative form and gold standard of

arthroscopy- Adhesions released with blunt probes or

instrumentation (radiofrequency or laser)- Confirm disk mobilization depressing

retrodiskal tissues and manipulation of mandible

Arthroscopic Maneuvers

Arthroscopic ManeuversReleasing Procedures


radiofrequency

fibrillations

Ablationlaser


synovitis

disk removal

synovitis

Laser aiming beam

Condylotomy• Condylar sag aids range of

motion and internal derangement

• Complications include malocclusion and sensory

disturbances

Arthrotomy – Total Joint Reconstruction

Arthrotomy – Total Joint Reconstruction

Adjunctive MeasuresDistraction Osteogenesis

Condyle recreated post-condylectomy or

prosthetic joint failure

AURICULAR CARTILAGE

• Witsenburg 1984, Matukas 1990, Kent and Widner 1990

• Somewhat operative technique dependent

• Stabilization varies

• Early complication minimal

• Fun procedure - otoplasty effect

DISC REMOVAL WITH AUTOLOGOUSTEMPORALIS MUSCLE/FASCIA FLAP:

INDICATIONS

• Disc replacement where significant vertical dimension (up to 4-5mm) of the condyle has been lost and lateral pterygoid function of the mandibular condyle has not been compromised

• Patient refuses a graft from an additional donor site

DERMIS GRAFTSClinical-Georgiade 1957, Zetz and Irby

1984, Meyer 1988

• Disc repair

• Disc replacement

• Ankylosis cases - thickness of dermis depends on gap

• With costochondral grafting

• Resembles a disc when used as a patch in perforations

• Reported superior ability to withstand joint loading compared to other tissues

DERMIS GRAFT

De-epithelializing prior to dermis harvest

Dermis in monkey - Tucker

FOSSA - ARCH - EMINENCERECONSTRUCTION

• Large fossa perforation and thinning - cranial, rib

• Large fossa perforation with arch loss - iliac crest, cranial

• May be done with partial/total joint procedures

INDICATIONS• Condylar height loss greater than 7-8 mm• Loss of lateral pterygoid muscle• Trauma• Multiple joint surgery• Advanced rheumatoid-disease and DJD• Ankylosis• Hypoplasia

15YrPostop

TECHMEDICA - TMJ CONCEPTS• Custom CAD/CAM design based on CT,

computer generated plastic model, and surgeon imput

Health & Medicine

TMJ Anatomy