ABSTRACT
Objective:To investigate the safety and feasibility of modified pararectus abdominis approach in the anterior plate fixation of sacral fractures.Methods:In 5 fresh adult cadavers (3 males and 2 females), gross anatomy was performed on one pelvic side using a modified pararectus abdominis approach to clarify the anatomical structures around the approach. On the other side of the pelvis, the anterior structures of the sacrum were exposed in simulated anterior plate fixation of sacral fracture via the modified pararectus abdominis approach. The exposed anatomic range of the approach, and the locations and courses of lumbosacral trunk nerve and iliac vessels were observed and recorded.Results:(1) The modified pararectus abdominis approach exposed the whole S1 vertebral body from the sacroiliac joint to the medial side, the L5 vertebral body cephalally, the S1 foramina in the true pelvis, and the same structures laterally as a traditional pararectus abdominis approach did. (2) Via the modified pararectus abdominis approach, exploration and decompression of the lumbosacral plexus (from L4 to S1) (including S1 foraminoplasty) were performed under direct vision to decompress the nerve entrapment from anterior compressed fracture fragments and hyperplastic callus. (3) There was a safe surgical area in anterior L5 and S1 where a plate could be safely fixed to the S1 vertebral body. (4) Since the maximum vertical distance from the lumbosacral trunk nerve lifted above the periost to the sacral ala was 1.4 cm (range, from 1.2 to 1.5 cm), a plate could be safely placed from the subperiosteum to the S1 vertebral body to fix the fracture.Conclusions:The modified pararectus abdominis approach is safe and feasible for exploration and decompression of lumbosacral nerves in the anterior sacral region (from L4 to S1) because it has significant advantages in vision and operation. It also broadens the range of anterior sacral plate fixation because a sacral fracture displacement can be reduced under direct vision and a plate can be fixated to the S1 vertebral body along the alae sacralis and across the sacroiliac joint to the iliac bone.