Anatomical Location of the Bowel in Different Surgical Positions: Implications for Lateral Access in Prone Single-Position Surgery.

Abstract

Study design: Radiographic analysis.

Objective: Evaluate the anatomical relationships of the bowel to the lateral surgical corridor and the spine in various surgical positions.

Summary of background data: Retroperitoneal transpsoas lateral lumbar interbody fusion (LLIF) may be performed with patients in the prone position, allowing for lateral and posterior approaches to the spine without repositioning the patient. Few, if any, studies discuss changes of the bowel position during these procedures.

Methods: Ten healthy volunteers underwent MRI in 3 positions: supine, prone with hips extended (prone-extension), and right lateral decubitus (left side up) with hips flexed (lateral decubitus-flexion). Anatomical relationships of the bowel to fixed spinal landmarks were assessed at L1-5, and the changes among participants' positions were compared.

Results: Anterior bowel movement was noted with prone-extension (range: 0.32-1.39 cm) and lateral decubitus-flexion (range: 0.97-2.18 cm) positioning compared with supine positioning. Significant anterior movement of the bowel was observed at L1-2 (P=0.03) and L2-3 (P=0.04) disc levels in participants in the prone position and at L2-3 (P=0.002) and L3-4 (P=0.01) in those in the lateral position when compared with those in the supine position. No differences in bowel movement were found for prone and lateral positioning. The percentages of participants with bowels located in the operative corridor were similar among the surgical positions (all P>0.07). 3D volumetric analysis showed that the magnitude of these changes was greatest for the upper left colon.

Conclusions: The results showed that the bowel was positioned anteriorly at L1-5 disc levels when participants were in prone-extension and lateral decubitus-flexion positions compared with the supine position. Overall, the magnitude of bowel positional change was small and variable. These findings suggest that the bowel does not fall away from the surgical corridor when performing retroperitoneal access for single-position prone surgery compared with the lateral decubitus-flexion position.