To determine the efficacy and safety of hyperbaric oxygen therapy (HBO) for overt mandibular osteoradionecrosis. This prospective, multicenter, randomized, double-blind, placebo-controlled trial was conducted at 12 university hospitals. Ambulatory adults with overt osteoradionecrosis of the mandible were assigned to receive 30 HBO exposures preoperatively at 2.4 absolute atmosphere for 90 minutes or a placebo, and 10 additional HBO dives postoperatively or a placebo. The main outcome measure was 1-year recovery rate from osteoradionecrosis. Secondary end points included time to treatment failure, time to pain relief, 1-year mortality rate, and treatment safety. At the time of the second interim analysis, based on the triangular test, the study was stopped for potentially worse outcomes in the HBO arm. A total of 68 patients were enrolled and analyzed. At 1 year, six (19%) of 31 patients had recovered in the HBO arm and 12 (32%) of 37 in the placebo arm (relative risk = 0.60; 95% CI, 0.25 to 1.41; P = .23). Time to treatment failure (hazard ratio = 1.33; 95% CI, 0.68 to 2.60; P = .41) and time to pain relief (hazard ratio = 1.00; 95% CI, 0.52 to 1.89; P = .99) were similar between the two treatment arms. Patients with overt mandibular osteoradionecrosis did not benefit from hyperbaric oxygenation.
