Fat marrow embolism during intramedullary bone endoscopy: an experimental study in sheep.

We present a study designed to investigate whether the intramedullary bone endoscopy (IBE) procedure within the cavity of an intact long bone will create embolic loads on the lungs similar to that of other orthopedic procedures (e.g., stem implantation in total hip arthroplasty [THA]). In a sheep model, 10 animals underwent the IBE procedure with complete perioperative anesthesiology monitoring. The lungs were harvested postoperatively and examined for fat embolisms. One animal showed evidence of intraoperative fat embolism with temporary increases in mean pulmonary arterial pressure (MPAD) and the mean CO(2)-gradient. The histological examination in this animal revealed fat embolism with a 2% surface area of the investigated fields covered with fat vacuoles. All peri- and postoperative data on the other nine animals were normal. Our findings indicate that, as with other intramedullary manipulation in intact long bones, there is a potential risk for systemic fat excavation during IBE. However, the embolic load is much lower than the rates reported for other orthopedic interventions. Copyright 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.