Surgically denucleated porcine intervertebral discs (IVD) were
injected with BIOSTAT BIOLOGX Fibrin Sealant (FS), and the in vivo
effects were assessed over time by histological, biochemical, and
The objectives were to test whether the intradiscal injection of FS
stimulates disc healing.
SUMMARY OF BACKGROUND DATA
Disc avascularity prevents the deposition of a provisional fibrin
scaffold that typically facilitates soft tissue repair. Poor disc
wound healing leads to disc damage accumulation and chronic
inflammation characterized by overproduction of proinflammatory
cytokines and proteolytic enzymes.
Four lumbar IVDs from each of 31 Yucatan minipigs were randomized to
untreated controls; degenerative injury (nucleotomy); and nucleotomy
plus FS injection. Animals were killed at 1, 2, 3, 6, and 12 weeks
postsurgery. IVDs were harvested to quantify (1) architecture using
morphological and histological grading; (2) proteoglycan composition
using DMMB assay; (3) cytokine content using ELISA; and (4)
mechanical properties using quantitative pressure/volume
There was progressive invasion of annular tissue into the nucleus of
nucleotomy discs and concomitant reduction in proteoglycan content.
By contrast, FS supplementation inhibited nuclear fibrosis and
facilitated proteoglycan content recovery over time. FS discs
synthesized significantly less TNF-α than degenerate discs
(66% vs. 226%, P < 0.05) and had upregulation of IL-4 (310% vs.
166%) and TGF-β (400% vs. 117%) at 2 to 3 weeks posttreatment.
At the third week postsurgery, the denucleated discs were less stiff
than controls (pressure modulus 779.9 psi vs. 2754.8 psi; P <
0.05) and failed at lower pressures (250.5 psi vs. 492.5 psi; P <
0.05). The stiffness and leakage pressure of the FS-treated discs
recovered to control values after 6 and 12 weeks, respectively.
FS facilitated structural, compositional, and mechanical repair of
the surgically damaged IVD. These FS-derived benefits are likely due
to its conductive scaffold properties and metabolically active
constituents such as thrombin, factor XIII, and aprotinin acetate.