The Impact of Central and Foraminal Stenosis Severity on the Need for Surgery After Epidural Steroid Injection.

STUDY

DESIGN

Retrospective Cohort Study.

OBJECTIVE

This study aimed to identify radiographic and patient-dependent factors that predict failure of epidural steroid injection (ESI) management, leading to subsequent surgical management in patients with lumbar stenosis.

SUMMARY OF BACKGROUND DATA: Lumbar stenosis is a common cause of radiculopathy and neurogenic claudication, and ESIs are a mainstay of conservative care. However, the benefits of ESIs are debated, and limited evidence exists on how stenosis characteristics correlate with the need for eventual surgery post-ESI.

METHODS

Adult patients (N=581) who received ESIs for lumbar radiculopathy or spinal stenosis between 2018 and 2021 were retrospectively identified. Subsequent lumbar spine surgery within two years of the first ESI was the primary outcome. Central and foraminal stenosis were graded using preoperative MRIs according to the Guen and Lee classification systems, respectively. Pre- and post-injection pain scores were collected. Multivariate logistic regression was used to determine significant independent predictors of subsequent surgery, accounting for age, body mass index (BMI), diabetes, Charlson Comorbidity Index (CCI), total number of ESIs, central stenosis, and foraminal stenosis.

RESULTS

Significant predictors of needing surgery within two years of the first ESI were age (OR 0.96; P<0.001), BMI (OR 0.96; 95% CI [0.92, 1.00], P=0.046), diabetes (OR 2.55, 95% CI [1.31, 4.96], P=0.010), total number of ESIs received (OR 1.83, 95% CI [1.46, 2.29], P<0.001), and foraminal stenosis severity (OR 2.50, 95% CI [1.79, 3.49], P<0.001). Central stenosis severity was not a significant predictor of surgery following ESI.

CONCLUSIONS

In patients treated with initial ESI, foraminal stenosis severity predicted the need for subsequent lumbar spine surgery. Additionally, age, BMI, diabetes, and cumulative number of ESIs were identified as independent predictors of surgery. These findings may assist physicians in counseling patients about the progression of their lumbar stenosis and in predicting the need for future surgery.

LEVEL OF EVIDENCE: III.