COMMENTARY
Jeffrey C. Wang, MD, Santa Monica, CA
The authors of this study present some very new and inter-
esting information regarding the ability of fibrin glue to limit
the amount of bone formation associated with a recombinant
growth factor. With increasing clinical experience and basic
knowledge of the characteristics of spinal fusion with re-
combinant growth factors, there is a concern that exuberant
bone formation may lead to nerve compression or bone for-
mation in undesirable areas. The results of this study by Patel
et al. suggest that the placement of fibrin glue into the inter-
transverse process area may serve as a barrier which pro-
hibits the formation of bone. While the results of this study
are very interesting, the reader is urged to understand this
experimental model so that an inappropriate conclusion or
translation into the human does not ensue.
It is important to realize that one is not typically trying to
block bone formation in the area of the intertransverse pro-
cesses. In fact, the historical or gold standard is an intertrans-
verse process fusion and this is the most desirable area for
bone formation. The product used in this report is unlikely
to ever be used in this location to prevent ectopic bone forma-
tion. Instead, this product may be used to try to block exuber-
ant bone formation emanating from this area, and this study
does not provide any data that this will result with the allow-
ance of bone formation along the transverse processes. In
fact, the results of this study may imply that it should not
be used in this area because it may inhibit spinal fusion.
If bone formation does occur in the course of a standard
intertransverse process fusion, this study does not demon-
strate that this product, if placed along the dura, will limit
the bone from growing and compressing the neurological
structures. The product may inhibit bone growth alto-
gether, but may not limit bone formation once allowed
to form. This is a very important conclusion that must
be understood.
This study provides valuable information; however, fur-
ther characterization of this interactive process must be
understood in order to determine definitively whether this
can prevent bone formation in the epidural space. Patel
and colleagues have added to our knowledge base in the
area of spinal fusion with growth factors. However, further
study is necessary to fully define the proper use and inter-
action of this fibrin product to limit the use of bone forma-
tion with the recombinant bone factors. I congratulate the
authors for this study and urge them to continue their
research in a more clinically applicable model so that we
can gain this information.
doi:10.1016/j.spinee.2006.01.001
404 V.V. Patel et al. / The Spine Journal 6 (2006) 397–404