John N. Kent1 and Christopher J. Haggerty2
1Department of Oral and Maxillofacial Surgery, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
2Private Practice, Lakewood Oral and Maxillofacial Surgery Specialists, Lees Summit; and Department of Oral and Maxillofacial Surgery, University of Missouri–Kansas City, Kansas City, Missouri, USA
A means of reconstructing acquired and congenital temporomandibular joint (TMJ) abnormalities.
- Reconstruction of defects resulting from acquired joint abnormalities (primary fibrous and bony ankylosis, infection, osteoarthritis, idiopathic condylar resorption, rheumatic diseases, neoplasms, and posttraumatic deformities)
- Reconstruction of defects resulting from congenital joint abnormalities caused by malformations of the structures of the first and second branchial arches (hemi-facial microsomia, Goldenhar syndrome [oculo-auriculo-vertebral syndrome], otomandibular dysostosis, and lateral facial dysplasia)
- Failure of components of alloplastic joint prosthesis, if scar bed is not excessive
- When reconstruction with an alloplastic prosthesis is cost-prohibitive
- Severe occlusal discrepancies involving the TMJ and associated structures that are not amendable to conventional orthognathic surgery
- Children without the complete eruption of the primary dentition
- Multiple operated joints
- Active infection
- Psychiatric disorders
- Medically compromised individuals: the very elderly, those with uncontrolled systemic diseases (chronic obstructive pulmonary disease, unstable cardiovascular issues, and poorly controlled diabetes), and those with drug and/or alcohol addiction
- Patients unable or unwilling to perform recommended postoperative physical therapy and cooperate with rehabilitation protocols
- Intravenous antibiotics, steroids, and antisialogues are given preoperatively. The patient is positioned supine on the operating room table and nasally intubated. Short-acting paralytics are used in order to test for branches of the facial nerve during the procedure. Separate intraoral and facial–chest instrument tray setups are created. Protective draping and/or redraping and prepping are always recommended throughout the procedure to avoid cross-contamination between the mouth and face–chest when going back and forth between sterile and nonsterile (oral) environments.
- A throat pack is placed within the posterior oropharynx. If orthodontic appliances are not in place, mandibular and maxillary Erich arch bars are placed, but maxillomandibular fixation (MMF) is not initiated.
- The patient is prepped in a sterile fashion. The oral cavity is prepped with Betadine paint (Betadine scrub is not recommended for mucous membranes application), and a sterile gauze is placed between the dentition and the internal surface of the lips to prevent the contamination of the extraoral field with saliva. The external auditory canals are prepped with Betadine paint, and an antibiotic impregnated ear wick is placed within the external auditory canals bilaterally. The remainder of the facial skeleton is prepped with Betadine paint from the scalp to the clavicles. The patient is draped to allow for exposure of bilateral pre-auricular and retromandibular incisions (even if only anticipating ipsilateral surgery) and the oral cavity.
- The head is turned 45° to the contralateral side. The affected joint is approached via a combined pre-auricular and modified-retromandibular approach (refer to Chapter 32). A nerve stimulator is used to test for branches of the facial nerve.
- A gap arthroplasty is performed from the glenoid fossa to the sigmoid notch. Diseased or deformed bone, scar tissue, and/or the involved condyle is removed, leaving a gap of approximately 15–20 mm from the ascending ramus osteotomy to the glenoid fossa. An ipsilateral coronoidectomy is performed. On occasion, if the patient has appreciable lateral pterygoid muscle function, the anterior aspect of the mandibular condyle with lateral pterygoid muscle attachment can be placed beneath the sigmoid notch area with a bone screw to preserve a portion of the lateral pterygoid function.
The glenoid fossa is smoothed or reshaped (Figure 33.6 [all figures cited in this list appear in Case Report 33.1]), and, if present, the native disc is preserved.
- After completion of the gap arthroplasty, the oral cavity is entered and mandibular movement is assessed to confirm unrestricted function. If mandibular movement is less than 35 mm, the gap arthroplasty site is inspected for interferences. Areas of scar tissue are removed from the ascending ramus, lateral and medial surfaces, and inferior border of the mandible. If interferences are identified on the contralateral side, a contralateral coronoidectomy should be performed. If contralateral interferences are present after coronoidectomy, contralateral open arthroplasty should be considered.
- After obtaining and confirming adequate mandibular movement, the patient is placed into MMF, the oral gauze located between the dentition and the internal surfaces of the lips is replaced, the patient is reprepped and draped extraorally with betadine paint, and the surgeon’s gloves are changed to prevent contamination of the extraoral surgical sites with oral microbes.
- The autogenous graft is harvested after the gap arthroplasty is completed and all interferences are addressed (Figure 33.7).
For costochondral grafts (CCGs), the cartilage head is reshaped to mimic a condylar head and to seat ideally within the glenoid fossa (Figure 33.8). Five to ten millimeters of cartilage are preserved at the rib– cartilage junction. The CCG should fit passively along the lateral surface of the ascending ramus while the CCG’s cartilaginous cap is seated within the glenoid fossa (Figure 33.10).
- In order to maximize CCG contact with the lateral ascending ramus, autogenous interpositional grafting may need to be performed between the CCG and the lateral a/>