Local Administration of Morphine for Analgesia after Iliac Bone Graft Harvest
We appreciate the comments by Dr. Sawyer and would like to address the two issues he has raised. All patients enrolled in our study discontinued the use of nonsteroidal anti-inflammatory drugs (NSAIDs) 7 days before surgery. In addition, patients were excluded from this study if they required long-term (≥ 6 months) preoperative opioids with a history of chronic pain.
The autogenous bone was harvested through a lateral oblique incision just cephalad to the iliac crest using a similar surgical technique described in the literature. 1,2The dissection then proceeded through the subcutaneous tissue down to the level of the iliac crest. After obtaining adequate exposure, an osteotome was used to cut through the crest in a sagittal direction exposing the bone marrow cavity. After bone was collected using curettes, morphine 5 mg in 10 ml normal saline was infiltrated directly into the exposed cancellous bone and bone marrow cavity using a 22-gauge spinal needle. Care was taken not to merely inject the morphine into the local surrounding tissues. The cortical iliac crest was then closed with interrupted suture and the soft tissue was closed in layers.
We believe the analgesic effect observed in our study was probably mediated through local opiate receptors because patients given the same dose of morphine intramuscularly failed to demonstrate any significant analgesic effect compared with saline treatment. Although previously performed in a rat model of bone damage, 3future human studies should also address the local administration of a μ-opioid receptor antagonist to further delineate the role of peripheral morphine for analgesia after iliac bone graft harvest surgery.