rhBMP-2 in the Reconstruction of Alveolar Clefts as an Alternative to Autologous Grafting
rhBMP-2 in the Reconstruction of Alveolar Clefts as an Alternative to Autologous Grafting
BACKGROUND: Secondary alveolar cleft reconstruction using autologous anterior iliac crest (AIC) is currently the gold standard treatment. Although highly predictable and successful, this additional surgical site is associated with considerable, although rare, donor site morbidities including significant postoperative pain, potential for infection, as well as gait and neurosensory disturbances. In an effort to minimize the morbidities associated with autologous graft surgery, a variety of grafting alternatives have been explored, including the use of recombinant human bone morphogenetic protein (rhBMP-2) on an absorbable collagen sponge (ACS). Bone morphogenetic protein is an osteogenic growth factor essential for embryologic development and formation of the skeleton. Minute quantities of these proteins are contained in the mature skeleton and are involved in bone healing and remodeling throughout life. When administered at a supraphysiologic level, bone morphogenic protein is found to be a potent inducer of de novo bone generation. INFUSE (Medtronic, Minneapolis, MN) is FDA approved for certain spinal fusion and maxillofacial procedures. In recent years, off-label use for alveolar cleft repair in pediatric patients has shown to be an effective and feasible alternative technique in the reconstruction of alveolar cleft defects.
METHODS: A chart review was conducted of 8 patients who underwent secondary alveolar cleft reconstruction using INFUSE (rhBMP-2/ACS) by a single surgeon (DCH). 3 females and 5 males were identified with age at time of treatment ranging from 7 to 13 years and an average age of 9.8 years. Of the 8 patients, 6 had unilateral alveolar cleft defects and 2 had a bilateral defects repaired with a total of 10 sites grafted. Post-operative i-CAT (Imaging Sciences International, LLC, Hatfield, PA) cone beam CT scans were taken at a minimum of six months following grafting procedures to assess success of bone formation at the alveolar cleft. Success was measured by evaluating bone height from nasal floor to alveolar crest, width, bone density using Hounsfield unit (HU), and radiographic evidence of bony continuity.
RESULTS: Reconstruction of alveolar cleft with rhBMP-2 resulted in an average height of 9.05 mm measured from nasal floor to alveolar crest and an average of 4.43 mm in alveolar width. Additionally, the bone density of the grafted sites resulted in an average of 522 Hounsfield unit (HU) compared to 468 Hounsfield unit (HU) of adjacent, non-grafted bone. 8 of 10 graft sites had radiographic evidence of bony continuity.
CONCLUSION: rhBMP-2 appears to be a viable alternative for secondary reconstruction of alveolar clefts. Reconstructive surgery using rhBMP-2 results in decreased operative time as well as elimination of donor site surgery and associated morbidities while achieving acceptable clinical and radiographic results.
References
- Chin M, Ng T, Tom WK, Carstens M. Repair of alveolar clefts with recombinant human bone morphogenetic protein (rhBMP-2) in patients with clefts. J Craniofac Surg. 2005 Sep;16(5):778-89.
- Herford AS, Boyne PJ, Rawson R, Williams RP. Bone morphogenetic protein-induced repair of the premaxillary cleft. J Oral Maxillofac Surg. 2007 Nov;65(11):2136-41.