The trajectory characteristics and clinical significance of the left-sided lumbar segmental artery: a prospective cross-sectional radio-anatomical study

Abstract

Background: Vascular injury to the lumbar segmental arteries is a devastating complication in minimally invasive lumbar interbody fusion. Previous studies on the anatomy of the lumbar segmental arteries are limited. This prospective cross-sectional study aims to quantitatively describe the brief trajectory of the lumbar segmental arteries on the left side (SegAL) and to discuss its clinical significance.Methods: One hundred and two asymptomatic volunteers were prospectively enrolled and underwent computed tomography angiography (CTA). Anatomical parameters including the existence rate, relative positions and directions of SegAL were measured. Mann-Whitney U tests were performed, and statistical significance was set at P<0.05.Results: A total of 404 lumbar SegAL were identified. The SegAL of L1, L2 and L3 were identified in all subjects while the L4 SegAL were absent in 9 of 102 (8.8%) and the L5 SegAL were absent in 97 of 102 (95.1%) volunteers. In 25 of 97 (25.8%) volunteers without the L5 SegAL, the branches of the L4 SegAL ran along the disks. Meanwhile, the branches of L3 intersecting over the intervertebral discs (IVD) were found in 8 of 9 (88.9%) subjects without the L4 SegAL and in 4 of 93 (4.3%) subjects with L4 SegAL. The branch angles between the L1, L2 SegAL and the aorta were significantly acute (P<0.05). The L3 SegAL ran approximately vertically with the aorta while the branch angles of the L4 SegAL were significantly blunt (P<0.05). according to the distances measured, on the anterior vertebral walls, the SegAL of L1 and L2 were significantly closer to the inferior vertebral walls than the SegAL of L3 and L4, while on the posterior vertebral walls, the L3 and L4 SegAL were significantly closer to the inferior walls.Conclusions: Arterial branches may course over the L3-4 and L4-5 IVD spaces and the branches over the L3-4 disks are more likely to be present when L4 segmental arteries are absent, thus posing potential risks of arterial complications. Because of the SegAL adjacent to the disks, the risk of arterial injury may be higher anteriorly at L1 and L2 and higher posteriorly at L3 and L4.

Biomechanical evaluation of a novel anatomical plate for oblique lumbar interbody fusion compared with various fixations: a finite element analysis

“…Thus, the plate length should be limited according to the vascular intervals between the segmental arteries. Our previous study used computed tomography angiography and acquired precise and comprehensive parameters of the segmental arteries (11). We found that the L5 segmental artery was absent in most people, and thus the length of the plates used for L4-5 OLIF could be designed more flexibly.…”

“…To address these issues, the authors completed a series of anatomical studies to acquire the anatomical parameters associated with the plate design for OLIF (11,12). Based on these parameters, we attempted to develop novel and safe lateral plates with an anatomical design.…”

“…An additional contralateral translaminar facet screw (outer diameters: 3.5 mm) was inserted from the contralateral aspect of the spinous process and then crossed the center of the facet joints and reached the base of the transverse process of the inferior vertebra; (V) two-screw lateral plate (TSLP): a cage (40×18×12 mm 3 ) was implanted with a conventional lateral plate (28×10×6.5 mm 3 ) fixed with two screws (length: 25 mm, outer diameters: 5.5 mm); (VI) anatomical lateral plate (ALP): according to previous research and our anatomical studies, we designed two ALPs for OLIF at L2-3 (length: 27 mm, width: 15 mm, height: 6 mm) and L4-5 (length: 35 mm, width: 12 mm, height: 6 mm) (Figure 2). The length of the plates depended on the distances between the adjacent lumbar segmental arteries to avoid arterial injury (11). The width was limited according to the surgical corridor (see Table S1).…”

Some considerations before the clinical application of the novel anatomical plate for oblique lumbar interbody fusion

“…We sincerely thank Dr. Pu and his colleagues for their interest and constructive comments on our article. In that paper, novel and safe anatomical lateral plates (ALP) with an anatomical design based on the parameters acquired in our previous studies were developed ( 1 , 2 ). The initial design was introduced and its biomechanical performance was verified with the comparison of various internal fixations.…”