Anterior Osteophytes at L3-L4 as a Primary Predictor of Adjacent Segment Degeneration After Lumbar Instrumented Fusion.

Abstract

Introduction: Degenerative lumbar spine disorder (DLSD) is a significant public health concern, presenting with low back pain, radicular leg pain, and reduced quality of life. Although conservative management is the first-line treatment, some patients require surgery due to persistent symptoms or progressive neurological deficits. Lumbar instrumented fusion is a commonly performed procedure for DLSD. Adjacent segment degeneration (ASD) is a frequent complication after spinal fusion, occurring at either the cranial or caudal side of the fusion mass. While the role of spinopelvic parameters in ASD is well recognized, radiological predictors for poor outcomes and complications remain less understood. This study aimed to identify preoperative radiological predictors of ASD in patients who underwent short-segment decompression and fusion for DLSD.

Materials and methods: We cross-sectionally evaluated radiological data of the patients who underwent short-segment decompression and spinal fusion for DLSD at a tertiary spine clinic between 2013 and 2023.

Results: In 209 patients, 31.6% (n = 66) developed radiological signs of ASD. Multivariable analysis revealed that the presence of anterior osteophytes at the L3-L4 level was a significant predictor of ASD (odds ratio [OR] = 3.528) in the overall cohort. When stratified by upper and lower fusion ends, anterior osteophytes at L3-L4 level (OR = 3.912-4.663) and intrafacet vacuum phenomenon at L2-L3 level (OR = 4.269-5.962) were positive predictors, while Modic changes at L4-L5 (OR = 0.284) and fatty infiltration in the multifidus muscle at L2-L3 (OR = 0.462) were negative predictors of ASD.

Conclusion: Preoperative anterior osteophytes at L3-L4 level were the strongest predictors of ASD following short-segment lumbar decompression and fusion. According to our results patients with Modic changes at lower levels and less fatty infiltration in the multifidus at upper lumbar levels were better candidates for lumbar decompression and fusion since they were less likely to develop ASD following surgery. These findings may aid clinicians in surgical planning and postoperative follow-up of patients with DLSD.