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 safely zone of the posterior ilium and relevant vital structures with regard to bone graft harvesting.
Summary of background data: The most frequently used site for bone graft harvesting is the posterior ilium. However, complications related to posterior iliac bone harvesting, such as donor site pain, neurovascular injury, instability of the sacroiliac joint, and herniation of abdominal contents, are still major concerns. Very little research with regard to the quantitative study of the posterior ilium has been reported.
Methods: Six cadavers (four male, two female) were used for the first part of this study. The posterior superior iliac spine was determined as a reference landmark. 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 the study involved 30 adult, dry iliac bony specimens. The posterior iliac region (extra-articular portion) was divided into three zones, and the corresponding dimensions of these zones were measured.
Results: The average distances from the posterior superior iliac spine to the superior 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, respectively. The average height for Zone 3 was 20.4 mm, and the average maximum thickness was 16.8mm.
Conclusion: The ideal area of the posterior ilium for bone graft harvesting was found in Zone 1. Zones 2 or 3 may be considered it a greater quantity of cancellous bone graft is required; however, the risk of injury to the sacroiliac joint and superior gluteal vessels in these zones is increased.