Radiographic anatomical analysis of the pelvic Teepee view / 中国骨伤

<p><b>OBJECTIVES</b>To research radiographic anatomy of the main structure of the pelvic Teepee view, including its azimuth direction and view anatomy structure.</p><p><b>METHODS</b>From June 2013 to June 2014 adult pelvic CT examination results were filtered, excluding skeletal deformities and pelvic osseous destruction caused by tumors, trauma, etc. The data of 2.0 mm contiguous CT scan of 9 adults' intact pelves was,selected and input into Mimics 10.01 involving 7 males and 2 females with an average age of (41.2±10.3) years old. Utilizing the software, the 3D CT reconstructions of the pelves were completed. Setting the transparency being high,the pelvic 3D reconstructions were manipulated from the pelvic anteroposterior view to the combined obturator oblique outlet view and fine-tuned till the regular Teepee-or teardrop-shaped appearance emerges. Cutting tools of the software were at the moment applied to separate the "Teepee" from the main pelvis for each reconstruction. Then the "Teepee" and the rest (main) part of the pelvis were displayed in different color to facilitate the analysis on the Teepee, iliac-oblique, and anteroposterior views.</p><p><b>RESULTS</b>The "Teepee" started from the posterolateral aspect of the anterior inferior iliac spine and finished at the cortex between the posterior superior iliac spine and the posterior inferior iliac spine in a direction of being from caudal-anterior-lateral to cranial-posterior-medial. The radiographic anatomical composition of the "Teepee" contained one tip, one base,and two aspects. With the inner and outer iliac tables being the inner and outer aspects of the "Teepee", the tip is consequently formed by their intersection. The base is imaged from the cortex of the greater sciatic notch. The medial-inferior-posterior portion of the "Teepee" contains a small part of sacroiliac joint and its corresponding side of bone of the sacrum.</p><p><b>CONCLUSIONS</b>The "Teepee" is a zone of ample osseous structures of the pelvis, aside from a small medial-inferior-posterior portion, the main zone of which can be accepted as a safe osseous zone for the anchor of implants stabilizing certain pelvic and acetabular fracture patterns. The Teepee view can be utilized as guidance for the safe percutaneous insertion of such implants.</p>

Influence of the included angle between anterior aspects of S2 and S1 vertebral bodies on pelvic inlet imaging in mid-line sagittal plane / 中国骨伤

<p><b>OBJECTIVE</b>To analyze the influence of included angle between the anterior aspects of S2 and S vertebral bodies on pelvic inlet imaging in the pelvic midline sagittal plane.</p><p><b>METHODS</b>Totally 58 axial pelvic CT scans were chosen as study objects including 43 males and 15 females,with an average age of 40.7 years old (ranged,18 to 68 years old). The angles between the anterior aspects of S2 and S1, vertebral bodies and the horizontal plane on midline sagittal CT reconstruction were measured to simulate the optimal S2 and S1 inlet angles. The included angle between the anterior aspects of S2 and S1 vertebral bodies was calculated by subtrocting the S1,inlet angle from the S2 inlet angle defined as a base number. Then, the impact of the calculated included angles on the pelvic inlet imaging was analyzed. Results:The S2 inlet angles averaged (30.5±6.5) degrees; the S inlet angles averaged (25.7±5.9) degrees. The difference between them was significant (t=3.35, P=0.001). Ten patients had zero angle between the anterior aspects of S2 and S1 vertebral bodies; 14 patients had negative angle, averaged-(8.9±8.1) degrees; 34 patients had positive angle,averaged (11.8+6.4) degrees.</p><p><b>CONCLUSION</b>The difference of included angle between the anterior aspects of S2 and S1 vertebral bodies leads to the difference between S1 inlet view and S2 inlet view in most cases, complicating the pelvic inlet imaging,and affecting the reliability of the application of pelvic inlet view. Utilizing the angles measured on the preoperative midlihe sagittal CT reconstruction to obatin the patient-customized S1 and S2 inlet views could accurately guide the S1 and S2 iliosacral screw insertion.</p>