Bilateral Total Temporomandibular Joint Replacement Utilizing Virtual Surgical Planning and Autologous Fat Grafting: A Step-by-Step Surgical Guide

Author: Dan Hawkins, DMD, Thomas S. Lee, MD

Affiliation:

Department of Oral and Maxillofacial Surgery, University of Pittsburgh (Pittsburgh, PA, USA)

Department of Otolaryngology, Virginia Commonwealth University ( Richmond, Virginia, USA)

Published: 07/21/2026

Abstract

End-stage temporomandibular joint (TMJ) disease presents a complex reconstructive challenge often complicated by severe malocclusion, bony ankylosis, and previous surgical failures. Total joint replacement (TJR) using custom, patient-specific prosthetic devices has emerged as the gold standard for restoring mandibular function, vertical ramus height, and a stable occlusion. This manuscript provides a comprehensive, step-by-step surgical protocol for bilateral TMJ reconstruction based on virtual surgical planning (VSP). We detail the surgical sequence, relevant surgical anatomy, intraoperative maneuvers, and critical surgical pearls designed to maximize functional outcomes while mitigating common complications, such as facial nerve injury, heterotopic bone formation, and occlusal discrepancies.

Introduction and Indications

Alloplastic total joint replacement of the TMJ is indicated for severe structural and functional degradation of the joint apparatus where autologous reconstructive options are contraindicated or unlikely to succeed. The primary clinical indications include:

• Bony or fibrous TMJ ankylosis: Often secondary to trauma, infection, or prior surgeries.
• End-stage degenerative joint disease (DJD): Severe osteoarthritis or osteoarthrosis failing conservative and minimally invasive management.
• Pathology requiring major resection: Benign or malignant tumors involving the condyle or glenoid fossa.
• Inflammatory arthropathies: Rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), or psoriatic arthritis causing progressive joint destruction.
• Idiopathic condylar resorption (ICR): Progressive, often bilateral loss of condylar volume resulting in a retrognathic mandible and an anterior open bite.

When these pathologies present with severe malocclusions, custom TMJ prostheses are uniquely suited to simultaneously reconstruct the joint anatomy and permanently restore a stable, predictable maxillomandibular relationship.

Preoperative Preparation, Patient Positioning, and Draping

Proper surgical preparation and draping provide adequate, uncontaminated exposure of the bilateral preauricular regions, submandibular/retromandibular regions, and the abdominal fat harvest site.

Anesthesia and Positioning

• Intubation: The patient undergoes nasoendotracheal intubation. The tube is carefully secured with tape and oriented away from the facial surgical fields.
• No paralysis: Confirm with the anesthesia team that no long term paralytics are given so that muscle stimulation from facial nerve can be detected.  Short term paralytics given during intubation is acceptable as its effects will wear off. 
• Orientation: The operating table is rotated 90 degrees away from the anesthesia team to allow unhindered bilateral access to the head and neck.
• Patient Stabilization: Both upper extremities are tucked securely at the patient’s sides.

Surgical Field Preparation

• Hair Management: The sideburns and temporal hair adjacent to the planned preauricular incisions are shaved in the preoperative holding area.
• Field Isolation: Silk tape and surgical blue towels are used to reflect and isolate the hair away from the surgical fields.
• Anatomic Marking Tape: Two specific strips of tape are placed on each side:
  1. The first tape delineates the temporal area.
  2. The second tape is placed in the posterior auricular crease, oriented parallel to the posterior border of the sternocleidomastoid (SCM) muscle. 

Pre-Prepping Maxillomandibular Fixation (MMF)

• Non-Sterile Screw Placement: Prior to the formal sterile prep and drape, intermaxillary fixation screws are placed under clean but non-sterile conditions.  MMF wires are not placed until condylectomy is performed to achieve desired occlusion. 
• Trajectory and Placement: Four to six Intermaxillary fixation (IMF) screws are placed transmucosally into the alveolar bone:
  • Posterior Screws: Positioned carefully between the roots of the mandibular and maxillary premolars and molars, avoiding root injury.
  • Anterior Screws: Positioned anteriorly between the central incisors. This strict anterior control is crucial to prevent an inadvertent postoperative anterior open bite.
• Alternative: Hybrid or Erich arch bars can be utilized if prolonged postoperative elastic traction is anticipated (if a patient is prone to dislocation). In this case, four IMF screws are utilized as no prolonged postoperative elastic MMF was required.

Sterile Draping and Field Maintenance

• Pre-incision Antibiotics: IV Cephazolin 1g or clindamycin 600 mg is given 30 minutes to 1 hour preoperatively (Pre-incision).  
• Antiseptic Preparation: The face and neck are prepped with iodine paint. Abdomen is prepped with an alcohol-based chlorhexidine and allowed to dry.
• Salivary Contamination Barrier: An iodophor-impregnated adhesive drape (Ioban) is placed over the mouth and central portion of the face. This isolates oral and salivary secretions from the sterile extraoral wounds.
• Auditory Canal Protection: A sterile cotton ball impregnated with povidone-iodine (Betadine) is placed snugly within the external auditory canal (EAC) to prevent fluid accumulation and cross-contamination.
• Eye Protection: Eyelids are taped closed.  
• Wound Isolation: The bilateral SCM muscles and clavicles must remain visible within the lower boundaries of the neck field. Blue towels are secured tightly to the skin using surgical staples.
• Abdominal Site Isolation: The abdominal harvest site is prepped and isolated with an Ioban drape, marked with a blue towel and clamp, and covered with a split drape for rapid intraoperative identification during the fat grafting phase.

Surgical Anatomy and Facial Nerve Preservation

Avoiding injury to the facial nerve (CN VII) is a principal technical demand of this procedure. Dissection must respect known safe tissue planes based on hard and soft tissue landmarks.

The Main Trunk of CN VII

The main trunk exits the stylomastoid foramen and can be reliably located:

• Approximately 1.0 cm deep and inferior to the tragal pointer.
• Roughly 3.0 mm from the tympanomastoid suture line.
• Approximately 7.0 mm superior to the posterior belly of the digastric muscle.

The Frontal (Temporal) Branch

The frontal branch innervates the frontalis and orbicularis oculi muscles. It travels within the superficial temporal fascia (temporoparietal fascia) and crosses the zygomatic arch along Pitanguy’s Line. This line connects a point 0.5 cm inferior to the tragus to a point 1.5 cm superior-lateral to the tail of the eyebrow. On average, the branch crosses the arch approximately 2.5 cm anterior to the bony EAC, traveling immediately superficial to the periosteum. However, the frontal nerve branch may lie as close as 8.0 mm to the EAC.

Surgical Pearl: To avoid the frontal branch, all vertical incisions and deep cut-downs onto the zygomatic arch must be executed as close to the external auditory canal as possible, minimizing anterior translation of instruments.

Step-by-Step Surgical Technique

1. Preauricular Exposure and Joint Space Entry

• Infiltration: Local anesthesia (e.g., 1% lidocaine with 1:100,000 epinephrine) is injected superficially along the pre-tragal incision line. Deep infiltration into the parotid gland tissue is strictly avoided to maintain the validity of intraoperative facial nerve monitoring.
• Incision: A preauricular skin incision is made using a #15 blade, tailored within a natural skin crease and curving posteriorly behind the tragus to maximize cosmetic concealment.
• Tragal Cartilage Landmark: The dissection proceeds bluntly using sharp scissors to identify the anterior face of the tragal cartilage. This cartilage is a reliable guide: maintaining a tight dissection plane immediately anterior to it leads directly to the TMJ capsule. Avoid dissecting through the tragal cartilage or along the posterior aspect as it will lead you into the external auditory canal instead. 
• Plane of Dissection: Through the preauricular incision, at the level of the zygomatic arch, dissection proceeds deep to the parotid while remaining close to the tragal cartilage to identify the deep temporal fascia. This ensure that the dissection is being performed posterior and superior to the facial nerve branches, specifically the frontal branch.
• Fascial Exposure: A two-surgeon technique (one retracting, one dissecting) is used to expose the superficial layer of the deep temporal fascia. This fascia is a distinct, dense, white, glistening layer located immediately superficial to the temporalis muscle.

Surgical Pearl: Fascial identity can be verified by making a small test incision through it; visualization of the underlying dark red fibers of the temporalis muscle confirms the correct plane. However, unnecessary incision into the muscle should be avoided to prevent significant, bothersome hemorrhage.

• Pocket Connection: The temporal pocket on top of the deep temporal fascia is then connected to the preauricular pocket. A nerve stimulator confirms the absence of neural elements before final tissue bands are divided. A Kitner sponge dissects and cleans the remaining overlying soft tissues off the fascia.
• Arch Cut-down: Blunt dissection exposes the periosteum over the zygomatic arch. A #15 blade incises through the periosteum along the long axis of the arch, directly over bone.
• Subperiosteal Elevation: A periosteal elevator is inserted into the subperiosteal plane. The surgeon rotates their hand downward and inferiorly to elevate the periosteal-fascial flap as a single unit, which carries and protects the frontal branch of the facial nerve. This reveals the lateral capsule of the TMJ in a tunnel-like fashion.
• Hemostasis: To manage the hypervascularity typical of previously operated joints, a neuro-patty soaked in 1:100,000 epinephrine or topical thrombin is placed temporarily into the tunnel.
• Capsular T-Incision: The superior joint space is insufflated with local anesthetic containing epinephrine, which balloons the capsule and confirms entry. A #15 blade makes a horizontal incision into the superior joint space along the arch, followed by a perpendicular vertical incision down the condylar neck (a classic T-incision approach).
• Condylar Head Exposure: Tenacious lateral capsular attachments are reflected cleanly off the condylar bone using a sharp periosteal elevator to expose the structural reference landmarks required for subsequent VSP cutting guides.
• Eminence Preparation: The anterior articular eminence and the glenoid fossa are completely denuded of soft tissue. The TMJ disc—often found chronically displaced anteromedially and structurally degenerated—is identified.

2. Risdon (Submandibular) Approach

• Marking: The inferior border of the mandible, the mastoid tip, and the anterior border of the SCM muscle are palpated and marked.
• Incision: A semi-lunar incision is marked approximately halfway between the angle of the mandible and the SCM muscle. Local anesthetic is infiltrated superficially.
• Platysmal Split: The skin and subcutaneous tissues are incised, and the platysma muscle is sharply divided.  Once you enter subplatysmal tissue plane, be aware of marginal mandibular nerve which can sometimes be present within this region. 
• Avascular Plane Navigation: Dissection proceeds through a relatively avascular plane bounded anteriorly by the tail of the parotid gland and posteriorly by the SCM muscle. This plane guides the surgeon directly to the pterygomasseteric sling at the mandibular angle.
• Sling Division: Electrocautery divides the pterygomasseteric sling down to the raw bone of the mandibular angle.
• Subperiosteal Ramus Elevation: A #9 periosteal elevator sweeps the masseter muscle off the lateral aspect of the mandibular ramus.

Surgical Pearl: During superior elevation along the ramus, the surgeon must remain strictly subperiosteal and avoid drifting too far anteriorly or superiorly into the retromolar region, which risks an inadvertent breach into the oral cavity and subsequent contamination of the hardware space.  Instead, follow the posterior border of mandible towards the condylar neck within the subperiosteal tissue plane. 

• Tunnel Connection: The subperiosteal dissection continues superiorly until it connects directly with the preauricular pocket. Digital palpation with a finger from the opposite hand placed down through the preauricular incision confirms a continuous, clean subperiosteal tunnel along the entire lateral surface of the ramus.

3. Virtual Surgical Planning (VSP) Guided Osteotomies and Resections

• Guide Placement: The custom titanium cutting guide is introduced through the Risdon incision and adapted onto the lateral ramus. It is critical to confirm that the guide sits perfectly flush against the bone with zero soft-tissue entrapment. Seating is verified visually and tactilely via both the Risdon and preauricular exposures.
• Guide Fixation: The guide is rigidly secured to the ramus using temporary fixation screws.
• Predictive Drilling: While the guide is securely adapted, the monocortical predictive screw holes are drilled through the guide sleeves. These holes correspond exactly to the final pre-planned screw positions for the definitive condylar prosthetic component.

• First Osteotomy (Condylar Neck): Under direct visualization through the preauricular window, an oscillating saw or ultrasonic piezo instrument makes the first osteotomy immediately inferior to the condylar head.

Surgical Pearl: The condylar neck can be extremely thin. To avoid catastrophic injury to the maxillary artery, inferior alveolar nerve, or lingual nerve lying immediately medial to the neck, the surgeon should cut only 3/4 of the way through the bone. A T-bar osteotome is then inserted into the kerf and twisted gently to complete the osteotomy via a controlled fracture.

• Condylar Head Removal: The Mobilized condylar head is grasped with a Kocher clamp, and a periosteal elevator releases the remaining fibers of the lateral pterygoid muscle. The specimen is delivered from the field.
• Second Osteotomy (Superior Ramus Cut): The remaining proximal mandibular segment is shifted superiorly. The second osteotomy is performed through the preauricular incision along the superior shelf of the cutting guide to resect the target bridge of bone. Again, the 3/4-depth rule is applied, and a T-bar osteotome completes the fracture.
• Coronoidectomy: The coronoid process is grasped with a Kocher clamp. The temporalis tendon attachment is dense and highly vascular. Electrocautery is used directly on the bone to release the tendon and achieve immediate hemostasis. The coronoid process is removed.
• Disc Excision: The diseased TMJ disc is isolated with a tonsil clamp. Bipolar electrocautery divides its medial attachments and controls the bleeding typical of the retrodiscal tissue. The entire disc is excised.
• Final Fossa Preparation: The glenoid fossa and articular eminence are aggressively cleared of all remaining periosteum and soft tissue attachments to ensure a raw, stable bony bed for the fossa implant.
• Wound Packing and Isolation: The bilateral wounds are packed with neuro-patties soaked in epinephrine or thrombin and temporarily sealed with Tegaderm sheets. This isolates the wounds before any intraoral manipulation occurs.
• Contralateral Resection: Steps 1 through 3 are repeated identically on the contralateral side.

4. Maxillomandibular Fixation (MMF) and Occlusal Realignment

• Isolating the Mouth: A sterile drape is placed over the extraoral fields, exposing only the perioral Ioban barrier. A sterile drape is placed over rest of the field to keep rest of the field sterile except for the mouth.  Sterile instruments are kept separate from the instruments used intraorally.  The Ioban over the lips is sharply incised.  
• The Two-Operator Technique: Two surgical operators enter the oral cavity.
• Occlusal Seating: The mandible is manually manipulated to seat the dentition into the desired occlusion or the pre-planned VSP intermediate occlusal splint.
• Fixation: 24 gauge wires are passed around the pre-placed IMF screws, tensioned tightly using a wire driver, cut, and tucked.

Critical Warning: The patient must be placed into the exact pre-planned VSP occlusion. If the occlusion is inaccurate at this stage, the custom alloplastic hardware will not seat properly on the bone, requiring complete removal of the hardware, re-entry into the mouth, and re-establishment of MMF.

• Resealing and Re-scrubbing: A sterile operator will use Ioban drape to seal off the mouth.  Entire field is once again sterilized using iodine paint.  The non-sterile intraoral operators discard their contaminated outer gowns and gloves, perform a formal re-scrub, and re-enter the sterile extraoral operative fields.  

5. Prosthetic Component Implantation

• Hardware Preparation: The temporary titanium cutting guides are removed from the ramus bilaterally. The custom fossa and condylar prosthetic components are soaked in a sterile 10% Betadine solution.

• Fossa Component Insertion: The custom fossa component (comprising a high-density polyethylene articulating surface bonded to a titanium mesh backing) is introduced through the preauricular incision.
• No-Touch Technique: The implant must never touch the adjacent cutaneous margins during insertion to minimize the risk of bacterial biofilm contamination. The ultra-high-molecular-weight polyethylene articulating surface must not be scratched or grasped with sharp metal instruments; the component is handled strictly by its titanium mesh perimeter.
• Fossa Seating: Through the Risdon incision, a fossa seating tool applies steady superior and posterior pressure to drive the component firmly into its pre-planned anatomical position within the glenoid fossa.
• Fossa Fixation: Screw holes are drilled through the mesh. Standard holes generally accommodate 6.0 mm length screws, corresponding to the green indicator stripe on calibrated drill bits. While a four-screw configuration is structurally ideal, a minimum of three rigidly engaged screws is mandatory for long-term stability.
• Condylar Component Insertion: The titanium condylar ramus component is introduced through the Risdon incision and translated superiorly into the newly secured polyethylene fossa component.
• Coordinated Seating Verification: A second operator monitors the assembly through the preauricular incision to visually confirm that the prosthetic condylar head is perfectly centered and deeply seated within the fossa cup.
• Ramus Adaption: The ramus plate of the component is aligned with the pre-drilled predictive holes on the lateral surface of the ramus. A temporary plate clamp holds the plate flush against the bone.
• Condylar Fixation Sequence: Cortical screws are placed through the plate into the predictive holes.

Surgical Pearl: Do not torque any single screw to maximum tightness initially. Secure all screws to a light “two-finger tightness” to allow the plate to distribute stress evenly across the bone interface. Once all planned screws are successfully engaged, torque them tightly in a sequential pattern. Any remaining un-drilled screw holes in the plate design are then drilled bicortically and filled.

• Contralateral Implantation: The identical protocol is executed to place and secure the contralateral fossa and condylar components.

6. Autologous Abdominal Fat Harvest and Grafting

• Incision and Harvest: Attention is directed to the previously isolated peri-umbilical abdominal site. Local anesthesia is infiltrated, and a #15 blade creates a small cosmetic incision. Dissection proceeds through the subcutaneous tissue. The target fat pad is stabilized with Allis clamps and excised cleanly using cold scissors or electrocautery.
• Dead Space Management: The abdominal donor defect is checked for hemostasis, packed with a temporary hemostatic agent if necessary, and closed in layers using a 3-0 Vicryl suture for the deep fascial layers, 4-0 Vicryl for the subcutaneous tissues, and a running subcuticular suture for the skin.

• Graft Preparation and Placement: The harvested autologous fat graft is divided into two portions. Through the extraoral incisions, the fat is packed tightly around the articulating neck and head of the condylar component and within the margins of the glenoid fossa.

Surgical Pearl: The fat must be packed deeply along the medial aspect of the prosthetic condylar head. The medial raw bony borders of the osteotomy site are the most common sources of undesirable heterotopic bone formation; thorough coverage of this zone (medial to the TMJ hardware) is essential to prevent heterotopic bone formation and subsequent ankylosis.

7. Wound Closure and Postoperative Management

• Layered Extraoral Closure: The preauricular and Risdon wounds are irrigated copiously. Layered closure is executed to eliminate dead space and re-approximate anatomical boundaries:
  • Deep tissue and periosteal layers: 3-0 Vicryl buried sutures.
  • Subcutaneous/Submucosal layers: 4-0 Vicryl sutures.
  • Preauricular Skin: 5-0 Fast-Absorbing Gut sutures placed in an interrupted fashion.
  • Risdon Skin: 5-0 Monofilament nylon or fast-absorbing sutures in a cosmetic fashion.
• Final Occlusal Verification: The team returns to the oral cavity under non-sterile conditions. The MMF wires are cut and completely removed.  IMF screws are left in place for elastic MMF for 2-4 weeks.  The mandible is manually cycled through its range of motion to verify that the dentition returns smoothly and consistently into the ideal, predetermined maximum intercuspation without premature prosthetic contacts.
• Early Function Protocol: The patient is extubated and transferred to the recovery unit. For the first 2 weeks postoperatively, light training elastics are applied to guiding elastics. These elastics guide the mandible into proper occlusion and prevent the patient from translating the prosthetic condyle anteriorly over the eminence component, which risks acute postoperative dislocation.
• Physical Therapy: Aggressive, structured physical therapy must begin within the first 48 to 72 hours postoperatively to prevent intra-articular adhesion formation and maximize long-term mandibular translation and rotation.

Outcomes and Conclusions

The use of virtual surgical planning paired with custom alloplastic joint manufacturing allows for excellent predictability and accuracy in restoring posterior ramus height, establishing an ideal occlusion, and managing complex skeletal deformities.

As demonstrated by Dr. Hawkins, adhering to strict subperiosteal tissue planes, using VSP cutting templates, employing a meticulous “no-touch” technique for hardware insertion, and obliterating peri-prosthetic spaces with autologous fat grafts collectively result in stable outcomes. Patients typically exhibit optimal healing, preservation of facial nerve function, and a significant improvement in maximum incisal opening—progressing from a restricted preoperative opening of less than 20 mm to a functional postoperative range exceeding 40 mm.