Answer: Standard incision. The posterior iliac crest is a readily available source of bone graft for posterior arthrodesis of the spine. However, the donor site is frequently a source of morbidity, including infection, hematoma, pain, numbness, and hypersensitivity or irritability of local tissue.

A review of the anatomy of the iliac crest is essential to decrease the associated morbidity. The superior cluneal nerves arise from the first, second, and third lumbar dorsal rami and provide sensation to the region of the posterior iliac crest and the cephalad portion of the buttock. The nerves cross the iliac crest approximately eight centimeters lateral to the midline and seven centimeters cephalad to the posterior superior iliac crest. They pass through the thoracolumbar fascia proximal to the crest and lie in the subcutaneous tissue over the ilium, and they are at risk of being divided or of sustaining a traction injury during procurement of a bone graft when using a standard incision (Fig. 1). In this study, the authors evaluated the use of an incision that is perpendicular to the iliac crest (Fig. 1, modified incision). They found a significant reduction in postoperative pain, numbness, and tenderness in patients when they used the modified incision.

Colterjohn NR and Bednar DA: Procurement of bone graft from the iliac crest. An operative approach with decreased morbidity. J. Bone Joint Surg Am. 1997; 79:756-9.