Minimally invasive bone harvesting tools

The most readily available source for autologous bone graft used in spinal fusion (the gold standard) is the iliac crest. However, the open surgical a pproach for harvesting corticocancellous iliac bone is associated with a ma rked increase in morbidity. This study suggests two alternatives to the tra ditional open harvesting procedure. For anterior interbody fusion procedure s using a cage, the autologous bone is harvested regionally from a neighbor ing vertebral body. Alternatively, using minimally invasive techniques, a c ustom bone graft harvester with a flexible tube and cutting tip allows harv esting of autologous bone from a single entry point at the iliac crest. The effect on the mechanical strength of a lumbar vertebra of removing a cylin drical regional bone graft was studied in a cadaveric model. The bone defec t was Filled using three different filler materials: a porous tricalcium ph osphate plug, a porous tantalum plug, and a self-setting calcium phosphate cement. After plug removal, the vertebral body's strength in flexion/compre ssion loading was reduced significantly, but could be restored to at least intact values with any of the three filler materials. The minimally invasiv e bone graft harvester was tested in three cadaveric pelves. With the cutti ng tip being guided within the cortical boundaries of the pelvis, cancellou s bone volumes of 10-20 cc could be harvested from each iliac bone. Regiona l bone graft harvest in anterior spine surgery is suggested to be anatomica lly safe and biomechanically acceptable. Any of the three filler materials can restore the vertebral body's mechanical strength, but the filler's long -term resorption/remodeling or osteointegration behavior is unknown. The mi nimally invasive bone graft harvester is a novel tool, which performed sati sfactorily under laboratory conditions, but clinical results are still miss ing.