Fusion Rates of Patients Treated with rhBMP-2 - Spine ...
Fusion Rates of Patients Treated with
rhBMP-2 (Infuse) in Primary Multilevel
Posterolateral Lumbar Fusion Surgery
Michael Rivlin; Marjorie M. Mariller, MD, MPH; Chan
Roonprapunt, MD, PhD; Catherine N. Petchprapa, MD; Kevin
Math, MD; Fabien D. Bitan, MD; Andrew M. Casden, MD;
Michael G. Neuwirth, MD; Paul Kuflik, MD, FAAOS
The Spine Institute of New York
at Beth Israel Medical Center
Presented at IMAST 13th Annual Scientific Meeting
• Spinal orthopedic surgery often requires the fusion of
multiple vertebrae in order to ensure fixation of the
• Indication of spinal fusion or arthrodesis are:
– cases that have increased axial instability or deformity that
has a high probability of progressing.
– degenerative disorders of the spine
– curvature deformity
– vertebral fractures
– herniated nucleus pulposus
• Fusion can be achieved using different grafts and
– autologous grafts harvested from the patients iliac crests
– allografts, synthetic materials that enhance bone growth
(often complemented with instrumentation to insure stability)
• The rates of fusion following an instrumented
posterolateral fusion with autograft vary from 43% to
83% and from 66% to 75% for 2-level fusions and 3-
level fusions, respectively.
• To determine the fusion rate of
patients treated with BMP undergoing
multilevel posterolateral lumbar
• Bone Morphogenetic Proteins (BMP) are
cytokines that belong to a family of TGF-beta
superproteins. There are 15 BMPs identified
(BMP-2 is used in the present study).
• BMP functions include:
– the induction of bone and cartilage formation due to
which they were named after
– maturation of osteocytes, chondroblasts, osteoblasts
– implicated in the process of angiogenesis in bone
• Recombinant techniques have enabled
scientists to purify BMP (rhBMP) free
from potentially infectious materials
• It is packaged in a collagen (type I) sponge
containing rhBMP and it is often applied
with fusion cage systems.
• Preparation of the implant is performed
intraoperatively by combining the BMP
infused collagen sponge and the
Mastergraft addedMastergraft added
Radiograph of the prepared implant
Implant to be usedImplant to be used
Rolled into shapeRolled into shape
BMP infused collagen spongeBMP infused collagen sponge
• In a retrospective review of patients operated at
the Spine Institute, we identified 28 patients who
had undergone primary two- or three level lumbar
fusion with rhBMP-2 for degenerative conditions,
such as stenosis, spondylolisthesis, and
degenerative disc disease.
• The cases of tumor, infection, or trauma were
• No patients had iliac bone crest harvested.
• The patients were retrospectively followed up at 3,
6, 12 and when available, 24 months.
• The diagnosis of pseudarthrosis was determined by
plain X-rays and scored by independent radiologists
using the posterior fusion grading system developed
by Lenke et al.
• Fusion was graded on a scale of 1 to 4 Levels -
grade 1 or 2 were considered as fused.
• Fusion was achieved by placing BMP graft over the
lateral recess of the exposed and decompressed
(laminectomy) spine. The graft was placed over the
decorticated bleeding bone.
Grade 1: Bilateral
Grade 2: Unilateral
solid fusion, partial
Grade 3: Partial
graft resorption with
no clear fusion
Grade 4: Bilateral
with no evidence of
Radiographic Criteria for Fusion
• 68% of the patients included in the study
were women. The patients’ mean age was
61 years old (range 33-80). The degenerative
conditions that were treated included
lumbar stenosis (79%), spondylolisthesis
(71%) and degenerative disc disease (32%).
BMI # of Pts. %
Normal 7 25%
Overweight 11 39%
Obese 9 32%
Morbidly obese 1 4%
• All twenty eight patients had undergone a
decompressive laminectomy, and instrumented
posterolateral fusion with BMP placement.
• The average amount of BMP placed was 9.4
micrograms per levels fused.
• Twenty-five patients underwent a 2-level fusion and
three patients underwent a 3-level fusion.
• Local bone was used in half of the patients.
Outcomes # of Pts Mean (95% CI)
Length of surgery (hh:mm) 28 4:10 (3:52-4:28)
EBL (ml) 27 637 (527-747)
Cell saver (ml) 28 114 (71-157)
Hospital stay (days)* 27 6.55 (5.84-7.26)
Complications # of Pts
Infection, return to OR 2
• Two out of the 28 patients received a blood transfusion
(they received one and two units of blood, respectively).
• Preoperative narcotic use was associated with lower
fusion rates (p=0.002); all patients without previous
narcotic use had a solid fusion. There was no
association between the fusion rate and the following
factors: smoking (p=0.107); preOp NSAIDS (p=0.630);
BMI (p= 0.232); and regular consumption of alcohol
• The fusion rate per level was 83% at last
follow-up (mean follow- up period was 12
months). Seventy nine percent of the
patients achieved fusion at all levels. Half
of the failures achieved partial fusion.
• Fusion rates of patients treated with rhBMP-2 in
primary multilevel posterolateral lumbar surgery
were similar to historic fusion rates reported for
multilevel instrumented arthrodesis using
autogenous bone graft. Therefore, rhBMP-2
represents a good option for obtaining successful
multilevel lumbar arthrodesis without the
associated historical graft site morbidity.
• As a future investigation, we plan:
– To measure the clinical and radiological
outcomes of BMP fusion for different surgical
approaches (posterior, anterior, lateral, etc)
– To focus also on the risk factors as
confounders, such as the effect of smoking and
NSAIDs, to observe the effect these play on