Long-Term Results of Radiation Prophylaxis for Heterotopic Ossification in the Temporomandibular Joint

Purpose: To assess the long-term efficacy and toxicity of radiation therapy (RT) for postoperative prophylaxis of recurrent heterotopic ossification (HO) in the temporomandibular joint (TMJ). Patients and Methods: Twelve patients (18 joints) with bony ankylosis of the TMJ from HO were referred to undergo RT after arthrotomy with osseous recontouring, gap arthroplasty, or costochondral grafting. Treatment consisted of 10 Gy in 5 daily fractions to a field encompassing the TMJ with an adequate margin. RT was initiated 1 to 3 days postoperatively. Response to therapy was assessed by routine x-ray films obtained preoperatively, immediately postoperatively, and at follow-up by use of the Turlington-Durr grading system. Treatment efficacy was defined as freedom from HO re-formation requiring further surgical intervention. Efficacy and toxicity data were obtained from review of the medical records and were augmented by telephone interview of patients when possible (6 patients, all with follow-up >16 years). Efficacy rates by patient were estimated by the Kaplan-Meier method. Results: The median follow-up after RT was 16.4 years (range, 2.5-19.2 years). Symptomatic re-formation of HO requiring further surgery occurred in 5 patients (7 joints). Treatment efficacy rates were 71% (95% confidence interval [CI], 44-99) at 5 years and 48% (95% CI, 15-80) at 10 years. Of the 6 patients contacted regarding late toxicity, 2 had clinical xerostomia (grade 1, CTCAE v3.0) attributable to RT; no other late RT-related toxicities were noted. None of the 12 patients had malignancy attributable to RT. Conclusions: Postoperative RT prevented re-formation of TMJ HO in 50% of treated patients long term. Late toxicities from RT were mild and infrequent.