Which patient factors predict poor outcomes or higher complication risk after ESIs?
Executive summary
Epidural steroid injection (ESI) outcomes are influenced by a mix of psychosocial, clinical and anatomical factors: preexisting psychological distress or depression, longer symptom chronicity, and underlying pathology such as lumbar spinal stenosis predict poorer clinical benefit, while certain procedural and anatomical variables (cervical/thoracic level, injection approach, steroid formulation) are associated with higher risk of serious spinal adverse events; overall complication rates are low but serious harms, though uncommon, cluster by level and technique [1] [2] [3] [4] [5] [6].
1. Psychological state drives response — distress and depression forecast worse outcomes
Multiple studies and reviews find that higher preprocedure psychological distress and depressive symptoms are associated with worse absolute patient‑reported outcomes and higher disability after ESI, and screening for psychological distress can help identify patients less likely to derive meaningful benefit [1] [2] [7].
2. Chronicity of radiculopathy blunts benefit — longer symptom duration predicts poorer effect
Evidence and expert summaries report that chronic radiculopathy is generally less responsive to ESIs than more acute complaints, with chronicity offered as a plausible explanation for variable and often short‑lived benefit in the literature [3] [8].
3. Pathology matters — spinal stenosis and low‑grade nerve compression alter outcomes
Subgroup analyses and trials indicate that patients with lumbar spinal stenosis tend to get less improvement from ESIs and in some cohorts experienced no outcome benefit compared with non‑ESI care, whereas disc‑related radiculopathy (herniation) can be more amenable to short‑term relief; overall, systematic reviews stress persistent uncertainty and heterogeneity in which pathologies predict durable success [4] [9] [10].
4. Objective tests and biomarkers show promise but are not yet definitive predictors
Imaging grading of nerve‑root compression and laboratory signals such as elevated interferon‑gamma from epidural lavage have been proposed as predictive tools for short‑term pain reduction after ESI, but the current evidence is limited and conflicting, requiring larger validation studies before routine clinical use [11].
5. Age, opioids, insurance and satisfaction — sociodemographic signals with mixed implications
Older patients often report greater satisfaction with ESIs in observational data, while preinjection opioid use and payer status (Medicare vs private insurance) have been linked to differences in postprocedure satisfaction and outcomes in some studies; these associations may reflect underlying disease severity, expectations or access rather than causal effects of age or insurance per se [12].
6. Complication risk concentrates by spinal level and technique — cervical/thoracic injections and certain approaches carry higher SSAE risk
Large administrative analyses show that serious spinal adverse events (SSAE) are more likely after cervical or thoracic ESIs than lumbar/sacral injections, and unadjusted event rates vary by injection approach and corticosteroid formulation; fluoroscopically guided ESIs generally show low rates of minor complications (typically transient increases in pain), but measurement limits, low event counts and coding limitations leave residual uncertainty about patient‑level modifiers of risk [5] [6] [13].
7. What the evidence cannot yet say with confidence
Systematic reviews and recent multicenter studies emphasize that despite many studies, reliable, consistent prognostic factors for ESI success are few; confounding, heterogeneous definitions of “success,” variable follow‑up intervals and limited adjustment for procedural choices mean that many putative predictors remain provisional and context‑dependent [10] [14] [9].