Response to Preoperative Steroid Injections Can Predict Early Outcomes in Patients Undergoing Fusion for Degenerative Spondylolisthesis.

Abstract

Retrospective cohort study. To determine whether response to preoperative steroid injection is associated with postoperative outcomes in patients undergoing lumbar fusion for degenerative spondylolisthesis (DS). While injections are common practice in conservative management for DS, it remains unclear whether a positive response to injections is associated with clinical outcomes after surgical intervention. A retrospective review of prospectively collected data was performed on adults undergoing primary lumbar fusion for DS from 2013-2021. Patients were grouped into control (no preoperative injection) and injection cohorts as well as positive versus no response to injections. Demographics, visual analog scale (VAS) back and leg scores, PROMIS Physical Function (PF), PROMIS Pain Interference (PI), and Oswestry Disability Index (ODI) were collected. Injection success was defined as ≥50% pain reduction. Surgical response was assessed using minimal clinically important difference thresholds. Baseline characteristics were compared using Student t tests, and linear regression evaluated associations between injection response and postoperative outcomes. Among 148 patients undergoing posterolateral instrumented fusion, 105 (70.9%) achieved ≥50% symptom relief after injection. Baseline outcome measures did not differ between cohorts (P >0.05). The overall cohort demonstrated significant postoperative improvement in PROMIS PF, PROMIS PI, ODI, and VAS scores at all time points (all P <0.05). Positive injection response was independently associated with greater improvement in ODI at 1 year (β=14.0, P=0.023) and higher PROMIS PF at all time points except 3 months. No significant associations were observed for VAS back, VAS leg, or PROMIS PI. Most patients with DS experience symptomatic relief from injections, and postoperative outcomes improve regardless of injection response. However, a positive injection response is associated with greater improvement in disability and physical function following fusion, which may aid preoperative counseling and shared decision-making. III.