Retropsoas iliac artery: potential cause of complications in lumbar spine surgery

Abstract

This patient presented with low-back pain and unilateral leftsided sciatica, which were attributed to a spondylolisthesis at L4–5 with an associated spinal canal stenosis. The patient was treated with a spinal canal decompression and spondylodesis using the minimally invasive transforaminal lumbar interbody fusion (TLIF)1–3 technique. Pedicle screws were placed bilaterally pecutaneously under fluoroscopic guidance. A muscle-splitting tubular system was used on the left side for spinal canal decompression and transforaminal cage placement. There were no surgical complications. Preoperative MR imaging demonstrated a retropsoas course of the right iliac artery together with a very narrow anatomical relationship to the right L-4 nerve at its exit point from the intervertebral foramen that resulted in a limited nerve displacement (Fig. 1). In this setting the right iliac artery lies caudally and ventrally to the right L-4 transverse process (Fig. 2). This variation, although rare,4,5 can complicate this spondylodesis procedure because the search for the transverse process with the Yamshidi needle to achieve transpedicular insertion is blind and may result in an iliac artery laceration. The risk is accentuated in cases of right-sided sciatica that would necessitate an ipsilateral transmuscular tubular approach. Furthermore, the use of this minimally invasive approach for the treatment of a far-lateral disc herniation should be avoided. In conclusion, the retropsoas iliac artery is a very rare anatomical variation that can complicate lumbar spine surgery, and failure to identify it prior to a minimally invasive procedure may result in disastrous complications.