Iliac crest bone graft. Osteotome versus saw.

The strength of saw-harvested vs. osteotome-harvested Smith-Robinson iliac crest grafts from five fresh frozen cadavers was compared. Matched pairs of grafts were harvested, one with a saw and the other with an osteotome from equivalent locations on the two iliac crests of each pelvis. Grafts were tested to failure in axial compression, and load-displacement curves were recorded for each test. Yield load and displacement, ultimate load, and stiffness were calculated, and statistical analysis was performed with the Student t test and three-way analysis of variance. Evaluation of the 66 pairs of grafts revealed that saw-harvested grafts were consistently stronger than were matched grafts harvested with an osteotome. The middle third of the iliac crest produced significantly stronger grafts, and those harvested from younger donors were significantly stronger than those obtained from older donors. Of even greater clinical relevance, saw-harvested grafts were stiffer than osteotome-harvested grafts. Based on these findings, it is recommended that iliac crest grafts harvested for spine fusion be obtained with an oscillating saw rather than with an osteotome.