Use of an Oblique Obturator Radiograph in Aspiration at Anterior Iliac Crest

Nonunion of fractures and avascular necrosis of the femoral head remain challenging and clinically important problems in orthopedic surgery. The gold standard for bone grafting is autologous bone harvested from the iliac crest. However, significant donor site pain and morbidity have been reported by many authors, with rates as high as 30%.^1--8 Recently, surgeons have sought new strategies to optimize bone repair, including the use of bone marrow stem cells. Bone marrow stem cells have the potential to aid in the development and regeneration of tissues, including bone.⁹ As a result, the use of autologous bone marrow aspirate for bone grafting has been advocated as a means to provide an osteogenic cell source.¹⁰

The most commonly used sites of bone marrow aspiration include the posterior and the anterior iliac crest. Hernigou et al¹¹ found no substantial difference in the number of available progenitor cells between the anterior and posterior iliac crests, which makes either surgical technique clinically viable. The authors describe a method used to obtain bone marrow aspirate by 2 surgeons who worked simultaneously on an anterior iliac crest. In this technique, the trocar is pushed in by hand approximately 6 cm into the iliac crest and withdrawn 1 cm toward the surface through the same insertion site. This technique requires multiple perforations of the iliac crest and uses small (4 mL) volumes of aspirate to reduce peripheral blood.

Kitchel et al⁴ described anterior and posterior approaches for aspiration. Their anterior approach is similar to the approach used by Hernigou et al.¹¹ For the posterior approach, the initial trajectory of the aspiration needle is approximately 40° lateral from the parasagittal plane and 35° to 40° inferior from the transverse plane. The aspiration needle can be advanced approximately 5 to 7 cm parallel to the line of the iliac crest. The needle must be removed and redirected in a different path to harvest additional marrow.

Although the procedures of these aspirations are usually regarded as being of low risk, they should not be thought of as being risk free.^5,12--16 Using the current approaches, it is possible to puncture the anterior cluneal and sacral nerves and vessels if the trocar does not remain in line with the edge...