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Posterior Spinal Fusion Rates When Augmented with Bone Morphogenetic Proteins 2008

General Spine

Marc P Underhill, MD,
Joseph Craig, MD, ChB, ASSR Member

Scientific Paper


To determine the efficacy of bone morphogenetic proteins used in combination with posterior spinal fusions and their ability to influence the rate of complete fusion, as determined by radiographic analysis.The study retrospectively evaluated radiographic outcomes of 63 patients whom underwent posterior spinal fusions coupled with the use of bone morphogenetic proteins, by one orthopedic spinal surgeon to determine their fusion rates.

Methods & Materials

The study reviewed post operative imaging of 83 patients who underwent posterior spinal fusions with the aid of bone morphogenetic proteins performed by a single senior staff orthopedic spinal surgeon between the years of 2003-2006. Imaging including primarily AP and Lateral radiographs, as well as CT and MRI were reviews by a second year radiology resident and a fellowship trained, senior staff musculoskeletal radiologist.

Of the 83 patients 20 were excluded for reasons ranging from lack of follow up imaging to prior spinal fusion. The remaining 63, 23 males ( ages ranging 34-75, mean 55.4 years) and 40 females (ages ranging 34-84, mean 63 years) were evaluated as to whether complete fusion (all levels involved with symmetric involvement), partial fusion (single side all levels and portions of the opposite side), or pseudoarthrosis was the outcome. The average time to complete fusion was obtained, as well as the average time to unilateral fusion, i.e. the individual sides including those fused sides in the partial fusion group. These groups were further broken down and evaluated by the number of levels of fusion.


Of the 63 patients only 2 (3%)cases resulted in pseudoarthrosis. 49/63 (78%) completely fused with an average post operative time of 306.2 days. 12/63 (19%) resulted in partial fusion. The average time to total fusion by level was as follows: 2 level fusion (4/10 cases) complete at 183 days, 3 level fusion (17/21 cases) complete at 268 days, 4 level fusion (12/12 cases) complete at 400 days, 5 level fusion (9/10 cases) complete at 294 days, 6 level fusion (4/6 cases) complete at 392 days, 7 level fusion (3/3 cases) complete at 171 days, and complete fusion (0/1) was not obtained with 8 level fusion.


1.Fusion of the posterior spine is best evaluated on the AP film of the lumbar spine.
2.BMP is useful in aiding posterior fusion of the spine.
3.As the number of levels increase, the average time to fusion also increases.


1.)Underhill, Marc, M.D.
Radiology Resident Henry Ford Health Systems
2.)Craig, Joseph, M.D., Ch B
Senior Staff Musculoskeletal Radiologist Henry Ford Health Systems

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