Morphometric Analysis of the Retroperitoneal Vessels With Respect to Lateral Access Surgery in Adult Scoliosis.

Abstract

Cross-sectional study reviewing 62 magnetic resonance imaging or computed tomography scans from consecutive adult patients with scoliotic spinal deformity in the thoracolumbar spine. To investigate the variation in anatomic position of retroperitoneal vessels in relationship to curve direction, location, magnitude, and axial rotation of curves in adult scoliosis. The minimally invasive lateral approach to the thoracolumbar spine avoids manipulation of abdominal and retroperitoneal structures and decreases risk of injury to paraspinal musculature. In adult patients with scoliosis, the varying anatomic relationship between retroperitoneal vessels and intervertebral disk spaces can increase the risk of vascular injury. Axial images were used to measure the anterior-posterior diameter of the inferior vertebral endplate with respect to the disk space perpendicular to the widest length of the disk. The overlap of the retroperitoneal vessels with the endplate were measured at the cephalad end vertebra, apex, and caudad end vertebra of each curve. Overlap and accessible disk space for individual disk spaces were also measured. There was a significant difference in percentage overlap of the apex and cephalad vertebral endplate and inferior vena cava in right versus left-sided curves (P=0.002). Overlap between the inferior vertebral endplate and inferior vena cava at the cephalad, apex, and caudad end of the curve was significantly different between thoracolumbar and lumbar curves (P<0.05). Axial rotation significantly affected vessel overlap at multiple curve locations. There was a statistically significant difference in accessible disk space when approaching the curve from the concavity versus convexity. Overlap between retroperitoneal vessels and inferior vertebral endplates at the disk level in scoliotic spines varies significantly with direction of the curvature, level of the deformity, and degree of axial rotation. There is decreased accessible disk space and increased vessel overlap on the concavity of the curve. Surgeons, as usual, will take an individualized case by case approach to avoid approach-related vascular complications, but the general relationships reported in this study can guide side of approach.