Feasibility of L5-S1 oblique lumbar interbody fusion corridor based on lumbar MRI

WU Yu-xuan; BAO Bei-xi; YAN Hui; CHENG Xiao-kang; TANG Jia-guang

doi:10.3969/j.issn.2095-252X.2025.01.004

Abstract：Objective To evaluate and analyze the feasibility of L5-S1 OLIF corridor based on lumbar MRI. Methods 400 axial magnetic resonance images from Sep 2020 to Jun 2023 of the L5-S1 disc level were shortlisted (200 images for male and female each). Measuring DPI,DBI,morphology of iliac vessel,relative position between left psoas and intervertebral disc. Results The surgical corridor between left posas and iliac vessel wasn't observed in 43％ (172/400) of patients (grade 0),while only 8％ (32/400) was observed and suitable for surgery (grade Ⅱ). The average DBI was (26.2±11.7) mm. 75％ (300/400) had a high-rising psoas (AⅡ or higher),while low-rising psoas was 25％ (100/400). 56.8％ (227/400) iliac veins got perivascular adipose tissue below. Conclusions When the surgical segment involves L5-S1,the possibility of OLIF surgery in this segment should be fully evaluated through preoperative imaging examinations. This level is more difficult for surgery than other surgical levels,with lower feasibility ratio,and most of approaches can through the iliac vascular space. However,some patients can still be operated through the psoas iliac vascular space. Surgeons should pay more attention to the assessment of iliac vein mobility during operation as well as the protection of iliac vessels,especially the left common iliac vein,during intraoperative traction to reduce the risk of vascular injury.