We performed a systematic review of the literature to determine the safety and efficacy of bone morphogenetic protein (BMP) compared with bone graft when used specifically for revision spinal fusion surgery secondary to pseudarthrosis. The MEDLINE, EMBASE and Cochrane Library databases were searched using defined search terms. The primary outcome measure was spinal fusion, assessed as success or failure in accordance with radiograph, MRI or CT scan review at 24-month follow-up. The secondary outcome measure was time to fusion.Objectives
Methods
In patients with osteoporosis there is always
a strong possibility that pedicle screws will loosen. This makes
it difficult to select the appropriate osteoporotic patient for
a spinal fusion. The purpose of this study was to determine the
correlation between bone mineral density (BMD) and the magnitude
of torque required to insert a pedicle screw. To accomplish this,
181 patients with degenerative disease of the lumbar spine were
studied prospectively. Each underwent dual-energy x-ray absorptiometry
(DEXA) and intra-operative measurement of the torque required to
insert each pedicle screw. The levels of torque generated in patients
with osteoporosis and osteopenia were significantly lower than those
achieved in normal patients. Positive correlations were observed between
BMD and T-value at the instrumented lumbar vertebrae, mean BMD and
mean T-value of the lumbar vertebrae, and mean BMD and mean T-value
of the proximal femur. The predictive torque (Nm) generated during pedicle
screw insertion was [-0.127 + 1.62 × (BMD at the corresponding lumbar
vertebrae)], as measured by linear regression analysis. The positive
correlation between BMD and the maximum torque required to insert
a pedicle screw suggests that pre-operative assessment of BMD may
be useful in determining the ultimate strength of fixation of a
device, as well as the number of levels that need to be fixed with
pedicle screws in patients who are suspected of having osteoporosis.
