Radiological Outcomes of PEEK Versus Rigid Rod Stabilization in Lumbar Spinal Stenosis Surgery: The Role of...

Background/Objectives: Lumbar spondylosis is a degenerative disorder that may require decompression and stabilization surgery. Rigid titanium rods provide strong fixation, whereas polyetheretherketone (PEEK) rods have been proposed to offer a more flexible load distribution profile. This study compared the radiological outcomes after PEEK versus rigid rod stabilization and evaluated whether the preoperative degenerative findings contributed independently to the postoperative adjacent segment radiological status. Methods: A retrospective cohort of 106 patients undergoing lumbar decompression and posterior stabilization (2020-2025) was analyzed. Rod allocation followed routine clinical practice rather than randomization. Radiological parameters (foraminal area, canal diameter, disc height, and facet volume) were measured preoperatively and at one year postoperatively. Baseline-adjusted ANCOVA models with HC3 robust inference compared PEEK and rigid rods across the two-, three-, and four-segment constructs. Additional models assessed the independent effects of preoperative facet effusion and Modic changes. Results: PEEK rods were associated with the statistically reliable preservation of spinal canal diameter, foraminal area, disc height (particularly in the three- and four-segment constructs), and reduced facet joint volume increase compared with rigid rods after multiple-comparison correction. The findings for the two-segment constructs were less consistent and partly influence-sensitive. Preoperative facet effusion and Modic changes showed no statistically reliable independent association with postoperative radiological outcomes after adjustment. Conclusions: PEEK rod systems were associated with favorable baseline-adjusted radiological preservation patterns, especially in long-segment stabilization. These findings should be interpreted as radiological associations rather than proof of clinical superiority or causal reduction in adjacent segment disease, because rod allocation was nonrandom and clinical, and fusion-related outcomes were not assessed.