TMJ Surgery Flashcards
Which diseases can occur in the TMJ?
TMJ dysfunction
Jaw dislocation
Osteo-arthritis
Rheumatoid arthritis
Chondromatosis
Foreign body granuloma
Infection
Traumatic damage
Radiation damage
Ankylosis
Tumours
Which factors are involved in the aetiology of TMD?
Macrotrauma- one sudden incident of direct mechanical trauma
Microtrauma- repetitive overloading of TMJ (related to stress, clenching, bruxism)
Anatomy- class II jaw relation
Occlusal factors- deep bite, disharmony, lack of teeth
What are the symptoms of TMD?
Pain- muscular, capsular, intra-capsular (inside disc)
Reduced mobility- limited opening
Clicking/crepitus
Locking
What are the different parts of the articular disc?
Front- attached to lateral pterygoid (pulls on disc anteriorly)
Bilaminar zone (prevents disc from getting detached from TMJ)
-> collagen fibres
-> part is attached to posterior of condyle and part is attached to posterior of eminence (pulls back into place)
Disc is thin in the middle and can get perforated
What can happen to the bilaminar zone as a result of TMD?
Over time bilaminar zone collagen fibres lose elasticity and lose recoil ability following clenching (derangement of the joint)
How can the Lateral pterygoid be palpated?
Palpate behind tuberosity (lateral surface of lateral pterygoid plate)
-> if this is sore it suggests spasm of the muscle due to clenching, grinding, bruxism
What is meant by internal derangement of TMJ? What causes it?
Pathological mismatch between capacity of TMJ and excessive function
-> Excessive lateral loading on surface of the condyle- disc can become completely anteriorly dislocated (cannot be brought back by bilaminar zone)
What is meant by anterior dislocation of the TMJ with reduction? (initial)
Patient opens with a click (sore)- bilaminar zone is able to bring disc back
What is meant by anterior dislocation without reduction? (if untreated)
Bilaminar zone is unable to bring disc back (no/less pain but cannot open mouth widely)
What are the options for conservative management of TMD?
Counselling- stress causing grinding
Pain management - painkillers, anti-inflammatory like ibuprofen (treat cause not symptoms)
Joint rest- avoiding chewing hard foods (but chew on both sides), limit mouth opening (support chin with hand)
Physio- relax spasming muscles through stretching, using heat
Restoring occlusal stability- if high tooth or filling
Bite appliance
What are the functions of bite raising appliances when treating TMJ)
Eliminates occlusal interference
Works as habit breaker against grinding
Opens mouth slightly (prevents condyle moving up and back at area of bilaminar zone which is usually most inflamed
-> reduced loading on TMJ
What is the issue with treatment of anterior dislocation without reduction?
It will require surgery
Which special investigations can be used to aid your diagnosis of TMD
OPT
Arthrography/arthroscopy
MRI (magnetic resonance imaging)
How is arthrography of TMJ carried out? What can be seen?
Inject radiopaque material (lipidome) into TMJ and take image
-> Visualise superior and inferior compartments (split by disc)
-> You would see the meniscus of disc sitting in front of condyle (normally- would be at centre of condyle)
Why is MRI helpful in diagnosis of TMD?
Shows how lateral pterygoid is attached to the disc
-> You can see if it is dislocated
What does arthroscopy allow?
It allows us to look inside joint space, particularly the superior compartment of TMJ (scope does not get into inferior)
-> we can check shape, perforation, for damage/inflammation
Which procedures can be done using an arthroscope?
Biopsy
Lysis & lavage- remove exudate
Disc reduction – release, cautery, suturing
Removal of loose bodies
Eminectomy
Which medicaments are used in Arthrocentesis?
Hyaluronic acid
Steroid
Ringer-lactate solution
What is the function of arthrocentesis?
Increases lubrication within joint
What are the potential complications of arthroscopic procedures in the TMJ?
Iatrogenic scuffing
Broken instruments
Middle ear perforation
Glenoid fossa perforation
Extravasation
Haemorrhage
Haemarthrosis
Damage to Vn & VIIn
Infection
Dysocclusion
Laceration of EAM
Perforation of tympanic membrane
Why surgical procedures can be carried out to help fix TMD?
Disc plication
Eminectomy
High condylar shave
Condylotomy
Meniscectomy
Condylectomy
Reconstructive procedures
What is a meniscectomy?
Complete removal of disc
What is disc plication?
Moving disc to where it should be?
How is disc plication carried out?
From a pre-auricular approach- cut skin, cut temporalis muscle/fascia, visualise zygomatic arch, grab anteriorly dislocated disc and stitch in place using black silk (non-resorbable)
When is disc plication considered?
Only after conservative management, arthroscopy and arthrocentesis
When is an eminectomy/condylectomy carried out?
If eminence or condyle is pronounced and causes obstruction of the disc returning to position
What are the indications for TMJ reconstruction?
Joint destruction- Trauma, Infection, Tumours, Previous surgery, Radiation
Ankylosis
Developmental deformity
Tumours – usually slow growing eg.
(i) Giant cell lesions
(ii) Fibro-osseous lesions
(iii) Myxomas
What is the issue with ankylosis of the TMJ?
Patient cannot open at all
What are the classifications of TMJ ankylosis?
Type I – Flattening deformity of condyle, little joint space & extensive fibrous adhesions.
Type II – Bony fusion at outer edge of articular surface
Type III – Marked fusion bone between upper part of ramus of mandible & zygomatic arch.
TypeIV – Entire joint replaced by mass of bone
What are the options when reconstructing the TMJ
Replace condyle- using graft from costo-chondral surface of rib
Using Bi Protheses- component 1 replaces fossa/eminence and component 2 replaces condyle
Which nerve can be damage in the pre-auricular approach?
Facial nerve
