Objectives: To determine the effect of indomethacin on the prevention of heterotopic ossification (HO) following spinal cord injury (SCI).

Setting: County Hospital, Miami, Florida, USA.

Methods: Sixteen patients were treated with slow-release indomethacin 75 mg daily and 17 patients received placebo for a period of 3 weeks. Prevention was started 21±14 days after SCI. In both groups of patients there was similar age of the patients as well as the level of SCI and ASIA impairment scale. Two methods were used to diagnose HO, bone scintigraphy and radiographic examination. Bone scintigraphy with technetium labeled methylene-diphosphonate was used for diagnosis of early stage, while radiography was used for diagnosis of late stage of HO development.

Results: A significantly lower incidence of early HO was found in the indomethacin group (25%) than in the placebo group (65%; P< 0.001). Similarly there was a significant reduction of late HO in the indomethacin group (12.5%) as compared to the placebo group (41%; P< 0.001).

Conclusion: Our data suggest that indomethacin used during the first 2 months after SCI is effective in prevention of HO in a significant number of patients.