Open Joint Surgery - ankylosis Flashcards
Complications
- Bleeding from STA, Internal maxillary artery, pterygoid plexus, middle meningeal artery, internal carotid artery
- Facial nerve palsy
- Auriculotemporal nerve injury, Freys syndrome
- Perforation into middle cranial fossa
- Perforation or laceration or injury to EAC
- Hemotympanum
- Infection
- Malocclusion d/t inadequate ramus height
- Material or equipment failure or breakage
- Reankylosis due to heterotopic bone formation
Types of open joint surgery
Discoplasty Discectomy Capsulorraphy Lateral pterygoid myotomy Temporalis myotomy Eminectomy AE augmentation (Dautrey/ Le Clerc) Condylectomy Condylotomy Excision of tumor Gap arthroplasty with grafts Distraction osteogenesis of condyle ramus unit Tmj recons with autografts Tmj recons with alloplasts
Surgical approach - preauricular approach
- Skin along tragal line
- Subcut tissue
- Temporoparietal fascia above ZA level (STV above TPF, ATN below TPF)
SMAS below ZA level - Dissection along Superficial layer of temporalis fascia (cephalad) and avascular plane along cartilage of EAC (caudal)
- Incision of superficial layer of TF
- Fat tissue
- Deep layer of TF
- At root of zygomatic arch down to periosteum
- Lateral capsule of tmj
Causes of ankylosis
Infection: otitis media, septic arthritis
Inflammatory: RA, Ankylosing spondylitis
Trauma: condylar fracture, hemarthrosis, previous open tmj surgery
Causes of ankylosis in kids
Trauma - fracture bleeding intracapsular, hemarthrosis, malunion (immobilisation), continuous function that acts like distraction
Infection - otitis media
Classifications or types of ankylosis
Sawhney
- Fibrous adhesions
- Bony fusion at lateral, no fusion on medial surface
- Bony bridge between ascending ramus & zygomatic arch
- Complete replacement of bone between ramus and skull base
He et al
- Fibrous union without bony component
- Bony ankylosis in lateral joint with >50% still intact
- Bony ankylosis in lateral joint with <50% intact
- Complete bony ankylosis
Treatment of ankylosis
Ankylosis release
By condylectomy
Gap arthroplasty: 1-2cm with interpositional graft like temporalis fascia / dermal graft / alloplastic (metal - titanium pin to prevent growth of bone at the condyle; or non metal - textile terylene? The one used for closing septal defect)
Costochondral graft - have potential to grow
Total joint replacement
- more n more ppl take it as a first option
- success rate is good
- may use fat graft to cover the metal to prevent ingrowth of bone in between the metal
Important to remove periosteum to prevent the stimualtion of bone growth N especially removing the medial side which is More difficult technically
How to chose different recons options of grafts
Interpositional arthroplasty options:
Temporalis fascia
Temporalis muscle —-> local pedicled flap with easy access, no second surgical site morbidity. Disadv flap can scar contracture.
Dermis - good coverage of overlying bone, low risk of donor site morbidity, Disadv epidermoid cyst.
Auricular cartilage - mimics disc. Easy technique. Low risk at donor site. Disadv, can tear or perforate. Has tendency to transform into osseous.
Reconstructive options In paeds: Costochondral graft Distraction osteogenesis In Adults: Costochondral graft Chondroosseous illiac graft Alloplastic total joint replacement
Preauricular incision
Preauricular incision
Important structure to avoid - eac
Incise thru skin
Use rednal to dissect and find eac
Go away from eac
Use diathermy tru subcut tissue
Find the sta and stv (when u dissect the artery/vein, the rednal goes parallet to the vessels to expose it
And then can go under it so its exposed
“Be more gentle to the vessels” - mike et al
Use artery forcep x2. Tip of the artery has to face together like this / \
Tie the vessel - hand tie 4/0 for smaller vessel (practice pls)
The sta and stv is aboce the fascia. Find the fascia. Incise the fascia
Dissect fascia parallel to the direction of the facial nerve
Once down to muscle, cut it
Down to bone
Retract flap using PE. Use zygomatic arch as reference. Retract all the way anterior exposing the art eminence
Expose the capsule and the normal ramus down to the sigmoid notch (carefuul of the maxillary artery at the sigmoid notch area)
Becos were doing gap arthroplasty. 1.5-2cm of the ramus needs to be cut out.
Incise the ankylotic capsule/fibrotic tissue with diathermy to allow better expsoure
Cut the ankylosis with bur 021
Exposw down the ramus 2cm from fossa
Once removed the ankylosis
Deep down is the lateral pterygoid muscle.
Describe the tx treatment algorithm for adult TMJ ankylosis based on Kaban protocol.
- Aggressive excision of the fibrous or bony union.
- Gap apthroplasty - min of 2.5-3.5cm gap
- Ipsilateral coronoidectomy
- Contralatrtal coronoidectomy
- Interpositional grafting (temporalos ms, fascia, fat, auricular cartilage, dermis)
- Reconstruction with CCG, chondro-osseous iliac bone graft, alloplastic total joint prosthesis
- Aggressive postop physiotherapy
Kaban protocol for pediatric ankylosis
- Aggressive excision of fibrous or bony fusion (gap arthroplasty)
- Ipsilateral coronoidectomy
- Contralateral coronoidectomy (if MMO<35mm)
- Lining of joint with temporalis fascia/ms or disc (if salvageable)
- Reconstruction of ramus-condyle unit (DO or CCG)
- if DO - immediate early mobilization postop
- if CCG - MMF not more than 10 days - Aggressive postop physiotherapy
What are pseudo ankylosis
Depressing zygomatic arch fracture Dislocated ZMC fracture Coronoid hyperplasia Myositis ossificans Temporalis ms scarring
Total joint replacement
Components consist of the condyle and the fossa
Requires 20mm vertical dimension for the component
2 types:
- Ready made stock prosthesis which allows one stage procedure
- Custom prosthesis. Requires 2 stage. Resection. And then CT Scan for custom joint fabrication. Recons.
Causes of failure of tmj prosthesis
Hardware
- breakage of hardware components
- loosening or displacement of hardware
- wearing through of the fossa material
- fixation failure
- prosthesis does not fit
Biologic
- infection
- immune mediated (allergy to nikel/titanium, foreign body reaction)
Operative
- bleeding from STA, IMA, pterygoid venous plexus, ICA, middle meningeal artery
- otologic complication (injury to the external auditory canal/cartilage, hemotympanum)
- nerve injury (ATN, temporal/zygomatic branch of facial nerve)
- intracranial injury (glenoid fossa thickness 0.9mm)
- malocclusion due to improper height of the ramus
Complications of tmj open surgery
8 groups of complications
- Vascular injury (STA, IMA, Masseteric art, Pterygoid VP, ICA, MMA)
- Nerve injury (ATN - Freys syndrome, facial nerve)
- Otologic complication (perforation of EAC, hemotympanum)
- Infection
- Failure of hardware
- Intracranial injury (perforation into cranial vault)
- Malocclusion (d/t loss of ramus height, intra art swelling)
- Heterotopic bone formation - reankylosis
