Does Anteroposterior Cage Position and Screw Orientation Influence Clinical/Radiographic Outcomes and Complications After Oblique Lumbar Interbody Fusion with Lateral Plate Fixation?

The objective of this study was to evaluate the influence of cage anteroposterior position and angulation, as well as plate and screw trajectory, in oblique lumbar interbody fusion with lateral plate fixation, on clinical and radiographic outcomes along with associated perioperative complications. A total of 47 patients undergoing OLIF-LP surgery were enrolled. Cases were divided into the anterior position group (APG) or the posterior position group (PPG) based on whether the cage was positioned anterior or posterior to the midline. Data were collected preoperatively and at 3 days, 3 months, and 12 months postoperatively. Radiographic parameters measured included LL, FSL, DH, and FH. Implant-related measurements comprised cage-device angle (CDA), superior screw to endplate angle (SSEA), and inferior screw to endplate angle (ISEA). Clinical outcomes included Back-VAS, Leg-VAS, ODI scores, and perioperative complications, to evaluate the impact of cage position on radiographic and clinical outcomes at different time points. No significant differences were found in clinical outcomes between the groups at any point. Radiographically, the APG showed greater improvement in FSL than the PPG (4.37±3.56° vs. 1.75±3.16°, p=0.012). The APG also had greater loss of FH during follow-up (p=0.024). Thigh/inguinal numbness was the most common complication (38.3%), and was more frequent in the PPG. SSEA positively correlated with FSL at final follow-up (r=0.408, p=0.004). When employing a lateral plate for fixation in OLIF, an anteriorly positioned cage yields superior improvement in FSL, whereas posterior placement more effectively maintains FH, albeit with an increased risk of perioperative neurological complications. Moreover, a larger SSEA was positively associated with improvement in long-term FSL.