Background: Successful arthrodesis in challenging clinical scenarios
is facilitated when the site is augmented with autograft bone. The iliac crest
has long been the preferred source of autograft material, but graft harvest is
associated with frequent complications and pain. Connective tissue progenitor
cells aspirated from the iliac crest and concentrated with allograft matrix
and demineralized bone matrix provide a promising alternative to traditional
autograft harvest. The vertebral body, an even larger reservoir of
myeloproliferative cells, should provide progenitor cell concentrations
similar to those of the iliac crest.
Methods: Twenty-one adults (eleven men and ten women with a mean age
of 59 ± 14 years) undergoing posterior lumbar arthrodesis and pedicle
screw instrumentation underwent transpedicular aspiration of connective tissue
progenitor cells. Aspirates were obtained from two depths within the vertebral
body and were quantified relative to matched, bilateral aspirates from the
iliac crest that were obtained from the same patient at the same time.
Histochemical analysis was used to determine the prevalence of vertebral
progenitor cells relative to the depth of aspiration, the vertebral level,
age, and gender, as compared with the iliac crest standard. The cell count,
progenitor cell concentration (cells/cc marrow), and progenitor cell
prevalence (cells/million cells) were calculated.
Results: Aspirates of vertebral marrow demonstrated comparable or
greater concentrations of progenitor cells compared with matched controls from
the iliac crest. Progenitor cell concentrations were consistently higher than
matched controls from the iliac crest (p = 0.05). The concentration of
osteogenic progenitor cells was, on the average, 71% higher in the vertebral
aspirates than in the paired iliac crest samples (p = 0.05). With the numbers
available, there were no significant differences relative to vertebral body
level, the side aspirated, the depth of aspiration, or gender. An age-related
decline in cellularity was suggested for the iliac crest aspirates.
Conclusions: The vertebral body is a suitable site for aspiration of
bone marrow for graft augmentation during spinal arthrodesis.