RADIATION TREATMENT OF HETEROTOPIC BONE-FORMATION IN THE TEMPOROMANDIBULAR-JOINT ARTICULATION

Purpose: The efficacy and toxicity of radiation therapy used for preve nting re-formation of heterotopic bone involving the temporomandibular joint are assessed. Methods and Materials: Ten patients (15 TMJs) wit h bony ankylosis of the TMJ were referred after reconstruction with co stochondral graft, gap arthroplasty, or debridement of heterotopic bon e. Treatment consisting of 10 Gy was delivered early postoperatively t o a field encompassing the TMJ with adequate margin. Response to thera py was assessed by comparison of routine roentgenograms obtained preop eratively, immediately postoperatively, and at last follow-up; the Tur lington-Durr grading system was used. Median duration of postoperative follow-up was 19 months. Results: Radiation therapy prevented ectopic bone re-formation in 10 (69%) of 15 TMJs with prior bony ankylosis. O f the 15 TMJs, 13 (87%) had improvement in their Turlington-Durr score s compared with the preoperative scores. Development of ectopic bone f ormation was prevented in 9 (90%) of 10 TMJs rendered Turlington-Durr grade 0 postoperatively. Eight of the 10 patients have remained asympt omatic. Treatment was well tolerated. The only complication experience d was parotitis in three patients. Conclusion: Radiation therapy is us eful for prevention of heterotopic bone redevelopment after TMJ operat ion. We recommend 10 Gy in 5 fractions beginning early postoperatively for high-risk patients. This strategy appears beneficial in this youn g patient population, who suffer significant pain and functional impai rment in the TMJ articulation.