Download - 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
TMJ PathophysiologyOsteoarthritis
Intermediate Stage- Increased degradation exceeds limited
synthesis- Progressive degradation and loss of structure
Clinical features
Pain
Limitation of opening
Joint noise
Arthroscopic findings
Advanced fibrillation
Thinning of articular cartilage
Disk displacement
Joint stenosis
TMJ PathophysiologyOsteoarthritis
Late Stage- Degradation of articular surfaces
Arthroscopic findings
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)
Arthroscopy Technique
Arthroscopy Technique
- 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
Arthroscopic Maneuvers
radiofrequency
fibrillations
Ablationlaser
Arthroscopic Maneuvers
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