Formation of Painful Seroma and Edema After the Use of Recombinant Human Bone Morphogenetic Protein-2 in Posterolateral Lumbar Spine Fusions

BACKGROUND: The use of bone morphogenetic proteins for fusion augmentation in spine surgery has increased dramatically in recent years. Information is continually emerging regarding the effectiveness and safety profile of these compounds. OBJECTIVE: We have noted an increased incidence in sterile seroma formation and painful edema after the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) for posterolateral lumbar fusion. We present a retrospective review to determine the incidence of seroma formation and to discuss its clinical implications. METHODS: We retrospectively reviewed the operative reports of patients who underwent posterolateral lumbar fusion with the addition of rhBMP-2. We identified all patients who required surgical exploration of a postoperative sterile seroma. RESULTS: Of the 130 patients who underwent posterolateral lumbar fusion with rhBMP-2, 6 (4.6%) were returned to the operating room for exploration of a sterile seroma. The total amount of rhBMP-2 delivered to the posterolateral space per patient was 2.1 to 14.7 mg (mean, 8.4 mg per patient). The patients were returned to the operating room 5 to 13 days (mean, 7.7 days) after their initial surgery, and infection was ruled out in all cases by intraoperative cultures. CONCLUSION: There seems to be an increased incidence of formation of sterile seroma and painful edema in the lumbar region after posterolateral fusion with rhBMP-2. This report, along with other series highlighting the potential complications of bone morphogenetic proteins, suggests that more caution should be used when these compounds are used. Further studies are required to better define the risks and benefits of using bone morphogenetic proteins for spine surgery.