Comparison between the outer table and intracortical methods of obtaining autogenous bone graft from the iliac crest

A prospective study in two groups of patients selected randomly.

To determine whether keeping the outer and inner cortices of the ilium intact, while obtaining bone graft, would result in reduced postoperative bleeding and less postoperative pain.

Donor site complications after harvesting bone from the iliac crest are frequent. They comprise pain and bleeding related to the large bone exposed, injuries to the cluneal nerve, and sacroiliac instability.

Sixty patients who were admitted for elective fusion of lumbar segments were included in the study. In half of them, the iliac bone graft was taken in the outer Table method (group A), which included the outer cortex and the cancellous bone beneath, and in the remaining 30 patients only the cancellous bone from between the cortices was collected (group B). The amount of bone harvested, and the time taken to obtain it, were measured, as was the blood volume in the drains. At fixed intervals after surgery and up to 2 years thereafter, the patients were asked to grade the severity of pain in their back and at the donor site.

Two years after surgery, 22% of the patients in group A and 17% of the patients in group B reported to have significant pain at the donor site. This difference was not found to be statistically significant, nor was the postoperative bleeding. The average amount of bone harvested in group A was 36 grams compared with 25.7 grams in group B, taking 14 minutes and 20.3 minutes, respectively, to harvest it. These differences were found to be statistically significant.

Preserving the iliac cortices, while obtaining bone graft, does not reduce the postoperative bleeding or the severity of pain at the donor site. In the intraosseous method, less bone is harvested and longer duration of surgery is required, compared with that of the outer Table method.