The iliac pillar - Definition of an osseous fixation pathway for internal and external fixation
Orthop Traumatol Surg Res . 2020 Jun 19;S1877-0568(20)30167-5. doi: 10.1016/j.otsr.2020.04.009. Online ahead of print.
Alexander von Glinsk, Sven Frieler, Ronen Blecher, Kajsa Mayo, Cara Beth Lee, Emre Yilmaz, Jens R Chapman, Rod J Oskouian, Shane Tubbs, Thomas A Schildhauer
Abstract
Background: Increasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium.
Hypothesis: We aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries.
Methods: Twenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 female, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: Location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition we measured the width of the different bone layers.
Results: The mean length of the hourglass shaped iliac pillar was 107.04mm with a mean width of 17.0mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o'clock. The smallest mean diameter of the cancellous bone was 7.5mm±2.0.
Conclusion: The iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway.
Level of evidence: Anatomical descriptive study.
Keywords: Crest pin; External fixation; Iliac crest; Iliac pillar; Pelvic ring fractures.
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