ANATOMIC CONSIDERATIONS FOR POSTERIOR ILIAC BONE HARVESTING

Study Design. This study analyzed bony features of the posterior ilium and relevant vital structures using cadavers and dry ilium specimens. Objectives. To determine quantitatively the safety zone of the poster ior ilium and relevant vital structures with regard to bone graft harv esting. Summary of Background Data. The most frequently used site for bone graft harvesting is the posterior ilium. However, complications r elated to posterior iliac bone harvesting, such as donor site pain, ne urovascular injury, instability of the sacroiliac joint, and herniatio n of abdominal contents, are still major concerns. Very little researc h with regard to the quantitative study of the posterior ilium has bee n reported. Methods. Six cadavers (four male, two female) were used fo r the first part of this study. The posterior superior iliac spine was determined as a reference land-mark. The distances from the posterior superior iliac spine to the superior cluneal nerves, the gluteal line , and the superior gluteal vessels were measured. The second part of t he study involved 30 adult, dry iliac bony specimens. The posterior il iac region (extra-articular portion) was divided into three zones, and the corresponding dimensions of these zones were measured. Results. T he average distances from the posterior superior iliac spine to the su perior cluneal nerves, gluteal line, and superior gluteal vessels were 68.8, 26.6, and 62.4 mm, respectively. The average width, height, and maximum thickness for Zone 1 were 34, 27.8, and 17.1 mm, respectively ; the measurements for Zone 2 were 16.5, 31.8, and 14.2 mm, respective ly. The average height for Zone 3 was 20.4 mm, and the average maximum thickness was 16.8 mm. Conclusions. The ideal area of the posterior i lium for bone graft harvesting was found in Zone 1. Zones 2 or 3 may b e considered if a greater quantity of cancellous bone graft is require d; however, the risk of injury to the sacroiliac joint and superior gl uteal vessels in these zones is increased.