Abstract:Objective To compare and analyze the clinical effects of modified crenel lateral lumbar interbody fusion（CLIF）via psoas major approach and oblique lateral lumbar interbody fusion（OLIF）via intermuscular approach in the treatment of degenerative lumbar spondylolisthesis（DLS）. Methods A prospective randomized controlled study was conducted on 130 patients with DLS admitted to the Shijiazhuang Third Hospital and the Hebei Medical University Third Hospital from June 2018 to April 2022. The patients were randomly divided into the OLIF group（n=65）and the CLIF group（n=65）using a random number table method. The OLIF group was treated with OLIF，and the CLIF group was treated with CLIF. The surgical conditions，postoperative recovery，levels of serum trauma stress factors［β - endorphin（β - EP），prostaglandin E2（PGE2），advanced oxidation protein products（AOPP），malondialdehyde （MDA）］，lumbar imaging parameters（lumbar lordotic angle，intervertebral height），lumbar function［Japanese Orthopaedic Association（JOA）score］，pain level［visual analogue scale（VAS）score］，complication rate，intervertebral fusion rate，fusion device settlement height，and fusion device angle with the coronal plane were compared between the two groups. Results There was no significant difference in operation time，intraoperative blood loss，postoperative ambulation time，postoperative drainage volume，and hospitalization time between the OLIF group and the CLIF group （P>0.05）. The levels of serum β-EP，PGE2，AOPP，and MDA in both groups on postoperative day 3 were higher than those before surgery（P<0.05），and decreased to near the preoperative levels on postoperative day 7. The lumbar lordotic angle and intervertebral height in the OLIF group were higher than those in the CLIF group at 6 and 12 months after surgery（P<0.05）. The JOA scores of the OLIF group were higher than those of the CLIF group at 6 and 12 months after surgery，while the VAS scores were lower than those of the CLIF group（P<0.05）. No complications such as incision infection，cerebrospinal fluid leakage，back pain，and muscle atrophy occurred in either group after surgery.At the last follow-up，the intervertebral fusion rate in the OLIF group（95.16%）was higher than that in the CLIF group（83.61%），and the angle between the fusion device and the coronal plane was smaller than that in the CLIF group（P<0.05）. There was no significant difference in the settlement height of the fusion device between the two groups（P>0.05）. Conclusion Both CLIF and OLIF are safe and effective methods for treating DLS. Among them，OLIF can moreeffectively improve postoperative lumbar function，reduce pain levels，and increase the interbody fusion rate. It also enhances lumbar lordosis angle and intervertebral height，reduces the angle between the fusion device and the coronal plane，and helps maintain lumbar stability.