Optimal Site for Bone Graft Harvesting from the Iliac Bone Poster No.: P-0095 Congress: ESSR 2015 Type: Scientific Poster Authors: B. Batohi 1, A. Isaac 1, J. Edwin 1, A. Hussain 1, J. Kumaraguru 1, L. M. Meacock 1, R. Powell 2, D. A. Elias 1, J. Compson 1 ; 1 London/UK, 2 Exeter/UK Keywords: DOI: Bones, CT, Surgery, Grafts 10.1594/essr2015/P-0095 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 14
Purpose Cancellous and corticocancellous bone graft is commonly retrieved from a site just posterior to the anterior superior iliac spine (ASIS) or just anterior to the posterior superior iliac spine (PSIS). Studies have shown harvest volumes from the ASIS are 13cm 3 and of the PSIS 30cm 3 on average 1. Occasionally larger volumes are required depending on the indication for harvesting. Orthopaedic surgeons often use a site approximately 10mm inferior to the iliac tubercle, to obtain grafts of varying types and quantity. The iliac tubercle (Fig 1) is a bony prominence arising from the iliac crest just posterior to the ASIS. The iliac ridge is a ridge of bone extending vertically along the lateral iliac bone from the iliac tubercle down to the acetabulum. The iliac tubercle and adjacent ridge are easily palpable and approached laterally. In some patients the iliac tubercle however is not palpable and an understanding of its relationship to the ASIS and PSIS would be of value. The aim of this study was to identify whether the site 10mm inferior to the iliac tubercle is the widest point along the iliac ridge from which bone could be harvested. The relationship of the iliac tubercle to the ASIS and PSIS was also evaluated. Page 2 of 14
Images for this section: Fig. 1: Iliac tubercle (arrow) and iliac ridge (arrowheads) on 3D surface reconstruction of the bony pelvis. King's College Hospital - London/UK Page 3 of 14
Methods and Materials The study included 20 CTs performed on adults aged 17-60 years old who had a CT of the pelvis performed as part of a major trauma CT protocol. Patients with acute or previous pelvic bony trauma, surgery, or significant congenital anomalies were excluded from the study. The 2mm axial bone reconstructions from each CT were manipulated on a workstation (Advantage windows, GE). A 3D surface reconstruction of the bony pelvis was used to identify the iliac tubercle (Fig 1). Using the workstation software, the identified location of the iliac tubercle was then transferred onto the corresponding axial images (Fig 2). A site along the iliac ridge 10mm (i.e. 5 slices) inferior to the iliac tubercle was then identified (Fig 3). The width of the widest portion of cancellous bone at this level was measured perpendicular to the axis of the bone from endosteal surface to endosteal surface (Fig 4). If there was a wider point along the iliac ridge inferior to this, it was also measured (Fig 5). The distance from this widest point to the iliac tubercle was determined by calculating the difference in the number of 2mm slices between the iliac tubercle and the slice with the widest point along the iliac ridge. The images were then reformatted to the original sagittal and coronal planes. The anterosuperior distance from ASIS to the iliac tubercle (Fig 6) and the PSIS to the iliac tubercle were measured (Fig 7). This study was conducted as an observational study with two observers independently recording measurements for each case. Intraobserver variability was calculated to determine the reliability of the data collected. The data was tested for normality using Shapiro Wilk's test and mean and median 95% confidence intervals were determined. Page 4 of 14
Images for this section: Fig. 2: Axial image of the iliac tubercle (arrow). King's College Hospital - London/UK Page 5 of 14
Fig. 3: Axial image showing a site along the iliac ridge 10mm inferior to the iliac tubercle. King's College Hospital - London/UK Page 6 of 14
Fig. 4: Axial image showing measurement of the width of the widest portion of cancellous bone at 10mm inferior to the iliac tubercle. King's College Hospital - London/UK Page 7 of 14
Fig. 5: Axial image showing the iliac ridge (arrow) which was assessment for a wider part of cancellous bone King's College Hospital - London/UK Page 8 of 14
Fig. 6: Sagittal reformat showing anterosuperior distance from the ASIS (arrow) to level of the iliac tubercle. King's College Hospital - London/UK Page 9 of 14
Fig. 7: Sagittal reformat showing measurement from the PSIS (arrow) to the level of the iliac tubercle. King's College Hospital - London/UK Page 10 of 14
Results 20 patients were included in this study. The age range was from 17-58 years old with a mean of 35.7 years. There were 6 female and 14 male patients. Measurements were taken from the right side of the pelvis apart from 5 cases where the right side was obscured due to artifact from something outside the patient. Measurements of distance from the iliac tubercle to the widest point on the iliac ridge: Reader 1 Reader 2 Mean 11.7mm 11.4mm Standard deviation 1.6mm 2.1mm Minimum 10mm 10mm Maximum 14mm 16mm Lower endpoint of 95% confidence interval 10.9mm 10.4mm Upper endpoint of 95% confidence interval 12.5mm 12.4mm There was no statistical difference between the two readers with a p-value of 0.5906. Measurements of distance from the iliac tubercle to the ASIS: Reader 1 Reader 2 Mean 56.3mm 59.8mm Standard deviation 11.0mm 8.9mm Minimum 39.7mm 42.7mm Maximum 74.1mm 73.4mm Lower endpoint of 95% confidence interval 51.1mm 55.6mm Upper endpoint of 95% confidence interval 61.4mm 64.0mm There was a statistical significance between the two readers in these measurements with p=0.0082. Measurements of distance from the iliac tubercle to the PSIS: Page 11 of 14
Reader 1 Reader 2 Mean 100.8mm 97.0mm Standard deviation 10.3mm 10.1mm Minimum 81.8mm 76.0mm Maximum 123.1mm 121.4mm Lower endpoint of 95% confidence interval 96.0mm 92.2mm Upper endpoint of 95% confidence interval 105.7mm 101.7mm There was no statistical difference between the two readers with a p-value of 0.0688 Page 12 of 14
Conclusion The study demonstrates that in our study group of CTs the widest point along the iliac ridge lies on average 11.5mm inferior to the iliac tubercle, with a range of 10-16mm. This information supports the current local orthopaedic practice of harvesting bone graft from 10mm below the iliac tubercle and suggests that a slightly more inferior (approx. 2mm) location may also be utilized. In patients with no palpable iliac tubercle, the widest point along the iliac ridge can be approximated 56-60mm posterosuperior to the ASIS and 97-101mm anterior to the PSIS. This study should advance the surgical approach to bone graft harvesting by improving the understanding of the anatomy of this site on the pelvis, thereby reducing complications and maximising bone graft yield. Page 13 of 14
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