Adverse events in patients re-exposed to bone morphogenetic protein for spine surgery

Study Design. Case series from a single spine specialty clinic. Objective. This study analyzed wound related or anaphylactic adverse events in patients re-exposed to rhBMP-2. Summary of Background Data. The use of recombinant bone morphogenetic protein (rhBMP-2) as a bone graft substitute is increasing. There is concern that re-exposing patients to rhBMP-2, might result in a hyper-inflammatory response causing wound problems or an allergic reaction. Methods. Ninety-six patients who had at least 2 spine surgeries using rhBMP-2 (Infuse, Medtronic Sofamor Danek, Memphis, TN) were identified. Anteroposterior surgeries, surgeries for infection and trauma were excluded. Demographic and operative data were collected from review of medical records. Surgeries were classified into primary, revision same approach and revision different approach. Logistic regression was used to control for variables associated with increased risk of complications. Results. During the first exposure there were 90 primary fusions and 6 revisions with 2 wound infections requiring debridements and 9 minor wound problems. During the second exposure there were 25 primary fusions, 50 same approach first revisions, 16 different approach first revisions, 1 same approach second revision and 4 different approach second revisions. There were 5 wound infections, 11 minor wound problems and no allergic reactions. There was no significant difference in the number of complications between the first and second surgeries or between patients who had a second primary surgery, a revision through the same approach or through a different approach. There were no wound problems or allergic reactions among twelve patients who had a third surgery with rhBMP-2. Conclusion. Multiple exposures to rhBMP-2, whether for a second primary surgery, revision through the same approach or revision through a different approach does not increase the risk of a wound infections/problems or result in clinically detectable allergic reactions.