STUDY DESIGN: A retrospective radiological study on vascular anatomy. OBJECTIVE: The aim of this study was to evaluate the anatomical and radiological features of lumbar segmental arteries with respect to the surgical field of the oblique lateral interbody fusion (OLIF) approach by using magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: OLIF surgery restores disc height and enables indirect decompression of narrowed spinal canals through an oblique lateral approach to the spine, by using a specially designed retractor. In a minimal surgical field, injuring segmental arteries can cause massive hemorrhage. METHODS: We reviewed 272 lumbar MRIs. In the sagittal images, the intersection of one-third of the anterior and median lines of the intervertebral disc (IVD) was considered the center of the virtually installed OLIF retractor. The cephalad/caudal distances from the center and branch angles of segmental arteries to the longitudinal axes of the aorta were measured to determine whether the segmental arteries run into the surgical area. Statistical significance was set at P < 0.05. RESULTS: The branch angles of segmental arteries were significantly acute (≤90°) in L1-L3 arteries and significantly blunt (>90°) in L4 and L5 arteries. The average distance to the center of the caudal adjacent IVD was significantly larger, and there were generally low possibilities for the existence of segmental arteries below half of the vertebral height, where the surgeons can install fixation pins with ease and safety. Among the lumbar segmental arteries, L5 showed specific characteristics with significant deviation, a four times (4.1% vs. L1-L3 segmental arteries) higher adjacency rate, and a two-fifth (38.6% vs. 100%) lower existence rate. CONCLUSION: Segmental arteries can be involved in the surgical field of OLIF especially in the lower lumbar spine level of L4 and L5 arteries, which can directly run across IVDs. L5 segmental arteries can also be iliolumbar arteries that have an abnormal trajectory by nature. LEVEL OF EVIDENCE: 4.
STUDY DESIGN: A retrospective radiological study on vascular anatomy. OBJECTIVE: The aim of this study was to evaluate the anatomical and radiological features of lumbar segmental arteries with respect to the surgical field of the oblique lateral interbody fusion (OLIF) approach by using magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: OLIF surgery restores disc height and enables indirect decompression of narrowed spinal canals through an oblique lateral approach to the spine, by using a specially designed retractor. In a minimal surgical field, injuring segmental arteries can cause massive hemorrhage. METHODS: We reviewed 272 lumbar MRIs. In the sagittal images, the intersection of one-third of the anterior and median lines of the intervertebral disc (IVD) was considered the center of the virtually installed OLIF retractor. The cephalad/caudal distances from the center and branch angles of segmental arteries to the longitudinal axes of the aorta were measured to determine whether the segmental arteries run into the surgical area. Statistical significance was set at P < 0.05. RESULTS: The branch angles of segmental arteries were significantly acute (≤90°) in L1-L3 arteries and significantly blunt (>90°) in L4 and L5 arteries. The average distance to the center of the caudal adjacent IVD was significantly larger, and there were generally low possibilities for the existence of segmental arteries below half of the vertebral height, where the surgeons can install fixation pins with ease and safety. Among the lumbar segmental arteries, L5 showed specific characteristics with significant deviation, a four times (4.1% vs. L1-L3 segmental arteries) higher adjacency rate, and a two-fifth (38.6% vs. 100%) lower existence rate. CONCLUSION: Segmental arteries can be involved in the surgical field of OLIF especially in the lower lumbar spine level of L4 and L5 arteries, which can directly run across IVDs. L5 segmental arteries can also be iliolumbar arteries that have an abnormal trajectory by nature. LEVEL OF EVIDENCE: 4.
Authors: André R Pinho; Pedro A Pereira; Maria João Leite; Cristina C Santos; Ricardo P Vaz; M Dulce Madeira Journal: Int J Spine Surg Date: 2022-07-14