A Comparative Study of the Static Histomorphometry and Marrow Content of Human Vertebral and Iliac Crest Trabecular Bone

Introduction: Cancellous bone architecture is an important determinant of bone strength. The iliac crest marrow is a gold standard graft during discectomy and spinal fusion procedures but is associated with donor site morbidity. Aim of the Work: In a trial to find an alternative, the aim of this work was to compare the structure andhistomorphometric measurements of the vertebral and iliac bones and assess their bone marrow cellular content and osteogenic potential. Methods: Vertebral body bone specimens were taken from four human subjects and specimens of iliac crest bone were obtained from five human subjects scheduled for surgery after taking their consent. Histomorphometric measurements were done in every specimen using decalcified and undecalcified sections. Osteogenic potential of the marrow progenitor cells was estimated by immunohistochemical detection of alkaline phosphatase expression. Results: Both vertebral body and iliac crest were seen consisting of branching and anastomosing trabeculae covered by cortical bone. However, the trabecular thickness and trabecular separation were significantly higher in the vertebral body than in the iliac crest. Moreover, the osteoid thickness and eroded surface were significantly greater in the vertebral body indicating more turning over activity as compared to iliac crest. The marrow content of nucleated cells was highly significant higher in vertebral body than that of the iliac crest. In addition, the osteogenic potential of the marrow progenitor cells showed no significant difference between vertebral body marrow and that of iliac crest. Conclusion: Static histomorphometric measurements of vertebral body differ from that of iliac crest. Meanwhile, vertebral bone marrow is rich in progenitor cells and its osteogenic potential is nearly the same as that of iliac crest, so vertebral marrow could be considered a suitable candidate for marrow graft supplementation in spinal fusion procedures.