Anatomic parameters of the sacral lamina for osteosynthesis in transverse sacral fractures

摘要

Purpose To analyze the morphometric parameters of the dorsal sacral lamina and pedicles to determine if there is adequate bony architecture to support plate osteosynthesis. Methods Two reviewers performed measurements on 98 randomly selected high-resolution CT scans of the pelvis to quantify the bony anatomy of?the sacral lamina. Measurements included the depths of the lamina at each sacral?level, the trajectory and depth of the sacral pedicles from the sacral lamina, and the width of the sacral canal. A bone mineral density analysis was performed on the sacral lamina using Hounsfield units (HU) and compared to the L1 and S1 vertebral bodies. Results The sacral lamina were found to form peaks and troughs which we refered to as major and minor sections.?On?average, the?thickness?was >?4?mm at all major screw starting points, indicating adequate geometry for screw fixation. The sacral pedicle depths were 27, 18, 16, and 14?mm at S2–S5, respectively. The average angulation from midline of this screw path directed laterally to avoid the sacral canal was 20°, 17°, 8°, and ??8° for the S2–5 pedicles, respectively. Average sacral canal diameter was 11?mm for S2 and 8?mm for S3–5. The sacral lamina had an average bone mineral density of 635 HU, which was significantly different from the density of the L5 (220 HU) and S1 (165 HU) vertebral bodies ( p ?