Analysis of the effect on costochondral graft for TMJ ankylosis with jaw deformities in pediatrics

ObjectivesTo evaluate the effects of costochondral grafting (CCG) used for temporomandibular joint ankylosis (TMJA) in growing patients.Materials and methodsPediatric patients with TMJA treated by CCG from 2010.5 to 2021.7 were included in the study. CT scans were performed before and after operations with at least 1 year follow-up. The height of the mandibular ramus, menton deviation or retraction, osteotomy gap, etc. were measured by ProPlan CMF1.4 software. CCG growth, resorption, and relapse were evaluated and analyzed with influencing factors such as age, ostectomy gap, etc. by generalized estimating equation.ResultsThere were 24 patients (29 joints) with an average age of 6.30 +/- 3.13 years in the study. After operation, the mandibular ramus was elongated by 5.97 +/- 3.53 mm. Mandibular deviation or retrusion was corrected by 4.82 +/- 2.84 mm and 3.76 +/- 2.97 mm respectively. After a mean follow-up of 38.91 +/- 29.20 months, 58.62% CCG grew (4.18 +/- 7.70 mm), 20.69% absorbed (2.23 +/- 1.16 mm), and 20.69% re-ankylosed. The re-ankylosis was negatively correlated with the osteotomy gap (OR:0.348,0.172-0.702 95%CI, critical value = 6.10 mm). CCG resorption was positively correlated with the distance of CCG ramus elongation (OR:3.353,1.173-9.586 95%CI, critical value = 7.40 mm).ConclusionsAn adequate osteotomy gap and CCG ramus elongation distance are the key factors for successful treatment of TMJA with jaw deformities in growing patients.Clinical relevanceTMJA affects mouth opening and jaw development in pediatric patients. The most common autogenous bone graft for pediatric patients is CCG due to its growth potential, convenient access and easy contouring. Also, it can simultaneously reconstruct the TMJ and improve jaw deformity by lengthening the mandibular ramus. But the growth of CCG is unpredictable. In this study, we explored several factors that may affect the absorption and re-ankylosis of CCG, expecting to provide several suggestions to improve future CCG treatment.