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An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
Transsacral versus modified pelvic landmarks for percutaneous iliosacral screw placement--a computed tomographic
C S Day1, M J Prayson, T E Shuler
1Department of Orthopaedic Surgery, University of Pittsburgh Physicians, Pennsylvania, USA.
American Journal of Orthopedics (Belle Mead, N.J.)
|September 30, 2000
Summary
The modified oblique technique offers greater accuracy for iliosacral screw placement compared to the traditional transsacral method. This improves safety and reliability in stabilizing sacroiliac joint injuries and sacral fractures.
Area of Science:
- Orthopedic Surgery
- Anatomy
- Radiology
Background:
- Iliosacral screw (IS) placement for sacroiliac joint stabilization typically uses the alar roots of the first sacral body.
- The traditional transsacral method aligns screws horizontally, while a modified oblique technique directs them inferiorly-superiorly and posteriorly-anteriorly.
Purpose of the Study:
- To define S-1 segment boundaries for both IS placement methods using 3-D CT scans.
- To evaluate and compare the accuracy of transsacral versus modified oblique IS placement in cadavers.
Main Methods:
- Analysis of 40 pelvic CT scans to determine S-1 segment dimensions for both techniques.
- Percutaneous IS placement in 10 cadaveric pelves using both transsacral and modified oblique landmarks, followed by CT confirmation.
Main Results:
- Modified oblique technique showed significantly larger anterior/posterior (18.0 mm) and superior/inferior (26.2 mm) measurements compared to transsacral (10.9 mm and 18.0 mm).
- Transsacral placement had 22.5% inadequate anterior/posterior dimensions (<7.3 mm) and 10% inadequate superior/inferior dimensions (<14.6 mm).
- In cadavers, 3 of 5 transsacral placements were errant, risking neurovascular complications, while all 5 modified oblique placements were accurate within the S-1 segment.
Conclusions:
- The modified oblique technique provides superior accuracy and reliability for percutaneous iliosacral screw placement.
- Modified oblique pelvic landmarks are recommended for percutaneous iliosacral screw stabilization of the posterior pelvis.
