Considerations for the Use of Alloplastic Temporomandibular Joint Replacement in Irradiated Patients: Report of an Off-Label Indication

Abstract

Background: Custom-made alloplastic temporomandibular joint replacement (ATMJR) is not validated in irradiated patients. However, in specific situations, after previous reconstructive surgical failures, the authors hypothesized the role of a customized ATMJR after radiotherapy.

Methods: A 65-year-old male patient was referred to Instituto Português da Face-Lisbon, Portugal-after failed attempts of mandibular reconstruction secondary to oral carcinoma resection and partial hemi-mandibulectomy plus radiotherapy of 60 total Grays. Primary reconstruction was performed with fibula free flap. Due to failure, secondary reconstructions were performed with osteosynthesis plate without success. The patient was unable to have adequate mastication and deglutition due to a severe crossbite. The authors treated the patient with an extended customized alloplastic temporomandibular joint replacement (F0M2).

Results: With 3 years of follow-up, the patient showed an improvement in masticatory function, mandibular motion, pain levels, and overall quality of life. No complications were observed related to ATMJR.

Conclusions: The presented case described how ATMJR, although not a validated option after radiotherapy, can be considered to restore functionality in complex cases with bone and soft tissues problems.

Keywords: adjuvant radiotherapy; free tissue flaps; head and neck neoplasms; temporomandibular joint; total joint replacement.

Figure 1

Preoperative clinical examination: (A) frontal view of the patient in rest position showing right hemifacial deformity; (B) frontal view of the patient during maximum mouth opening presenting right sever mandibular deviation; (C) left side maximum mouth opening; (D) right side maximum mouth opening, showing severe fibrosis in the right mandibular angle, submandibular and neck region.

Figure 2

Preoperative occlusion: severe cross-bite with deviation of the interincisal dental midline to the right side.

Figure 3

Preoperative 3D CT scan reconstruction showing preoperative malocclusion and the bone defect: (A) left-side view; (B) coronal view, with severe deviation to the right side; (C) right-side view, displaying the amount of bone missing from the different previous surgery.

Figure 4

Virtual surgical planning and custom-made temporomandibular joint prosthesis manufacturing: (A,B) coronal and right-side view of the preoperative CT scan 3D-reconstructed model in current malocclusion; (C,D) coronal and right-side view of the 3D model in planned transferred occlusion, with planned bone removal: condyle and coronoid process; (E,F) frontal and right-side view of the 3D-printed model with planning marks before prosthesis simulation model elaboration; (G,H) frontal and right-side view of the 3D-printed model with prosthesis plastic simulation model; (I,J) frontal and right-side view of the 3D-printed model with final version of the manufactured prosthesis: attention was made in the development of a smoothed mandibular angle. Red arrows in I-J indicate the details for screw.

Figure 5

Main surgical steps: (A) patient positioned in occlusion with inter-maxillary fixation; (B) dissection conducted from the submental area to the preauricular region by blunt tools (gauze showing the connection); (C) passage and fixation of the mandibular component in the partially fixed fossa component; (D) after confirmation of the correct condyle/fossa relation, fixation with all screws of all the elements.

Figure 6

Preoperative and postoperative 3D CT scan comparison: (A,B) coronal view comparison of the preoperative and postoperative CT scan 3D reconstruction, showing the large bone defect filled by the prosthesis positioning and facial harmonization; (C,D) right-side view of the preoperative and postoperative CT scan 3D reconstruction showing prosthesis profile and bettering in occlusion.

Figure 7

Postoperative phase: (A) postoperative occlusion, showing improvement in interincisal dental midline and resolution of the crossbite (B).

Figure 8

The 3-year-follow-up CT scan: (A) detail of the appropriate fitting of the alloplastic fossa to the temporal bone in coronal view; (B) three-quarter right view of the CT scan 3D reconstruction, showing stability of the obtained result.