Iliac Crest Bone Flap

Abstract

The possibility to transfer bone blocks of the ileum as parts of composite flaps from the groin donor site was described in anatomical studies by Taylor and Watson in 1978 [531]. These authors used this flap pedicled on the superficial circumflex iliac artery (SCIA) for reconstruction of compound defects of the lower leg. Whereas the blood supply of the SCIA was excellent to the skin, the bone blocks of the iliac crest were only perfused marginally by these vessels. Other vascular pedicles around the hip, such as the ascending branch of the circumflex femoral artery or the superior gluteal artery, were also used for microvascular transfer of composite flaps containing bone from the iliac crest [28, 230]. Although the vascular anatomy of the groin region, which was the first donor site for free flaps [15], was already investigated by Taylor and Daniel in 1973 [529], it took until 1979, when Taylor et al. [531] and Sanders and Mayou [454] described the first transfer of the iliac crest bone, using the deep circumflex iliac artery (DCIA) as the vascular pedicle. Both groups independently identified the DCIA to be the main nutrient vessel of the whole ileum. Since these first reports, the iliac crest proved to be a useful and reliable donor site, which, due to its anatomical shape, is ideally suited for the harvest of bone flaps to reconstruct defects of up to half a mandible [4, 40, 41, 112, 131, 146, 255, 256, 427, 524, 525, 553, 554]. Because of the high amount of bone available, endosseous dental implants can be inserted without problems, making the iliac crest the donor site of the first choice for functional masticatory reconstruction of the mandible and maxilla [427]. Sanders and Mayou also have shown that the DCIA provides blood supply to the overlying skin of the iliac crest by myocutaneous vessels [454]; thus, a skin paddle from the groin region can additionally be included and used for extraoral or intraoral reconstruction [255, 427, 553, 554]. Other flaps, such as the anterolateral thigh flap has been additionally transferred together with the iliac crest [293] to extend the skin territory for soft tissue reconstruction, performing additional anastomoses at the descending branch of the circumflex femoral artery. Because of the bulk and the limited maneuverability of the iliac crest skin paddle. Urken and coworkers introduced the inclusion of the internal oblique muscle into the iliac osteomyocutaneous flap [550, 553, 554]. He proposed to use this flat and flexible muscle for intraoral lining instead of the voluminous skin paddle. Although it was shown by Ramasastry et al. already in 1984 [417], that the internal oblique muscle is safely perfused by the ascending branch of the DCIA, thus offering the possibility to build a vascularised myo-osseous iliac flap pedicled on the DCIA, the internal oblique muscle was only used as an isolated muscle flap until Urken’s description. Apart from the decreased bulk, covering the iliac crest with the internal oblique muscle is advantageous for prosthetic rehabilitation following the insertion of endosseous dental implants. Due to the secondary atrophy of the muscle, a tight and flat residual tissue, similar to that of the attached gingiva will develop, allowing for good hygiene and loadability around the implants. The iliac crest internal oblique flap also has proven to be useful in covering skull base defects and to reconstruct the hard palate.