Fate of Costochondral Graft in Temporomandibular Joint Reconstruction: A Histological Study

Alloplastic TMJ replacement in the skeletally immature patient - A systematic review

This study assessed the current evidence for the use of TMJR reconstruction in skeletally immature patients. A systematic review was conducted according to PRISMA guidelines. An electronic search in PubMed and Embase was performed. Meta-analysis randomized controlled trials (RCTs), cohort studies, observational studies, case series, and case reports were eligible for inclusion. Case reports were also included due to the limited number of publications identified with the predefined terms. Exclusion criteria were: (1) studies written in a language other than English; (2) full-text unavailability (i.e., posters and conference abstracts). The selected studies were assessed for risk of bias. A meta-analysis was not performed as it necessitates a substantial between-study design homogeneity; hence, a descriptive synthesis of data was performed. There were 9 TMJR device reconstruction studies involving 14 subjects 13 years of age or younger. Follow-up ranged from 7 months to 120 months. All papers reported significant decrease in pain and improvement of diet. All prostheses were functional. No material failures of the prosthesis components were observed. The mandible continued to show limited growth following TMJR and most of the cases required no secondary or revision surgery even when the patient reached skeletal maturity. This systematic review had some limitations. The studies included had a low level of evidence and a high risk of bias. Most of the studies had a small patient sample, and no study had a control group. The literature reviewed supports the use of TMJR devices in the restoration of mandibular function and form in skeletally immature patients.

Custom Alloplastic Temporomandibular Joint Reconstruction: Expanding Reconstructive Horizons

Custom alloplastic temporomandibular joint (TMJ) reconstruction has been well established for the management of end-stage TMJ disease. However, its use in congenital TMJ deformities is limited. Here, the authors present initial outcomes of skeletally mature patients who underwent custom alloplastic TMJ reconstruction and simultaneous orthognathic surgery.A retrospective case series of patients who underwent custom alloplastic TMJ reconstruction concurrent with orthognathic surgery between 2014 and 2019 was completed. Functional, aesthetic and orthodontic outcomes as well as complications were recorded.Seven TMJs in 5 skeletally mature patients (4 female, 1 male, ages 16-30) (2 bilateral, 3 unilateral) were replaced. All but 1 patient had previous attempts at reconstructive surgery with poor results. All cases were prepared using virtual surgical planning and underwent concomitant maxillomandibular orthognathic surgery. All patients demonstrated improved post-operative occlusions. Four of 5 patients achieved >30 millimeters of post-operative MIO. Complications included ear canal perforation and facial nerve dysfunction.There were no infections or other implant-related complications. Mean follow up was 2 years and 15 days. Alloplastic TMJ reconstruction at the time of skeletal maturity for patients with congenital mandibular TMJ defects is an alternative to existing management options. Further long-term prospective outcomes studies are ongoing.

Biomechanical analysis of costochondral graft fracture in temporomandibular joint replacement

This study is the first attempt to explore the reason of costochondral graft fracture after lengthy mandible advancement and bilateral coronoidectomy by combining finite element analysis and mechanical test. Eleven groups of models were established to simulate costochondral graft reconstruction in different degrees of mandible advancement, ranging from 0 to 20 mm, in 2 mm increment. Force and stress distribution in the rib-cartilage area were analyzed by finite element analysis. Mechanical test was used to evaluate the resistance of the rib-cartilage complex. Results showed a sharp increase in horizontal force between 8 and 10 mm mandible advancement, from 26.7 to 196.7 N in the left side, and continue increased after 10 mm, which was beyond bone-cartilage junction resistance according to mechanical test. Therefore, we concluded that bilateral reconstruction with coronoidectomy for lengthy mandible advancement (≥ 10 mm) may lead to prominent increase in shear force and result in a costal-cartilage junction fracture, in this situation, alloplastic prosthesis could be a better choice. We also suggested that coronoidectomy should be carefully considered unless necessary.