Hyperbaric oxygen: a means of decreasing ischemic epiphyseal damage in a pediatric rabbit model

The effect of hyperbaric oxygen on epiphyseal ischemia was evaluated using a pediatric rabbit model. Forty-five animals were compared in this study: 23 from a control pilot study and 22 hyperbaric exposed animals. In each animal the right distal femoral and proximal tibial epiphyses were isolated on a popliteal vascular pedicle. The left leg acted as the control. The growth difference between the rabbit's hindlimbs was the means of comparison throughout the groups established. Warm ischemia was induced by applying a vascular clamp to the right popliteal artery for 12 hours (20 animals) and 7 hours (17 animals). The remaining 8 animals underwent a sham operation without interruption of epiphyseal perfusion. On completion of the ischemic period hyperbaric oxygen therapy (HBOT) was performed on 12 12-hour (12h-HBOT) and 10 7-hour (7h-HBOT) animals at 2 atmospheres for 90 minutes twice per day for 4 postoperative days. The animals were killed on either postoperative day 14 or 90. Measurement of longitudinal bone growth was performed on the 90-day animals from serial radiographs at the time of surgery and then at 1 month, 2 months, and 3 months after surgery. There was no significant difference in longitudinal bone growth between the sham-operated and the 7h-HBOT animals at 1, 2, and 3 months. There was a statistically significant difference, however, between the normal growth of the 7h-HBOT group compared with the abnormal growth of the 7-hour, 12-hour, and 12h-HBOT animals. Histology was consistent, with the bone growth data demonstrating relative normalcy of the 7h-HBOT group epiphyseal plates versus severe architectural aberrance and necrosis of the 12h-HBOT group epiphyses. Our experimental data indicate that a clinical trial should be instituted using HBO for pediatric replantation patients when warm ischemia exceeds 7 hours. (J Hand Surg 2000; 25A:159-165.