Bone Graft Donor Site Pain

· (a – Medtronic Sofamor Danek)

INTRODUCTION: Autogenous iliac crest bone graft has been the gold standard for spine fusion for years. In addition, donor site morbidity has been recognized, but often minimized in discussions with patients because there was not a good alternative. With the emergence of bone graft substitutes such as BMP, this merits re-evaluation. Further, there have been no good comparative studies of the relative morbidity of anterior vs. posterior iliac crest harvest, or the effect of volume of bone graft harvest on morbidity.

MATERIALS AND METHODS: 226 patients in 5 separate prospective, randomized studies comparing rhBMP-2 to autogenous iliac crest bone graft have been studied with the same donor site grading methodology. These studies include 1 level anterior lumbar interbody fusion using the LT cage (134 pts, avg. volume 5 cc); posterior lumbar interbody fusion with Interfix cage (34 pts, avg. volume 5 cc); 2 separate lumbar postero-lateral fusion studies with TSRH (42 pts, avg. volume 20 cc); and 1 anterior cervical diskectomy and fusion using a cervical cage (16 patients, avg. volume 1 cc). In all studies, presence or absence of donor site pain along with a 20-point visual analog pain scale specifically for donor site pain were recorded.

RESULTS: Nearly all patients had immediate donor site pain; 83% had pain at 6 weeks; 56% at 3 months; 43% at 6 months; 35% at 12 months; and 32% at 24 months. No rhBMP-2 patients had iliac crest pain. Composite average donor site pain score at hospital discharge was 13/20; at 6 weeks 7/20; at 3 months 5/20 which remained stable then through 24 months.

CONCLUSIONS: Harvesting bone graft is painful, regardless of the approach. The posterior approach is more painful, regardless of the volume of bone harvested from the posterior crest. Donor site pain decreases over time but the amount seems to plateau at 3 months. The percentage of patients experiencing pain decreases until about 12 months and then seems to remain stable.

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