Evaluating the effectiveness of interlaminar epidural steroid injections for cervical radiculopathy using PROMIS as an outcome measure

Background: Cervical interlaminar epidural steroid injections (CIESI) are frequently used to treat cervical radiculopathy due to cervical nerve root impingement.

Objective: The purpose of this study was to evaluate the therapeutic effect of CIESI for patients with cervical radiculopathy.

Methods: We conducted a retrospective review of consecutive adult patients with cervical radicular pain and corroborative cervical spondylotic foraminal stenosis on MRI that failed at least 6 weeks of conservative management consisting of medication and physical rehabilitation seen at a multidisciplinary, tertiary academic spine center. Patient Reported Outcome Measurement Information System (PROMIS) domains of Physical Function (PF) v1.2/v2.0 and Pain Interference (PI) v1.1 were collected at all patient visits. Scores were recorded at baseline, 3-months, 6-months and 12-months post-procedure. Statistical analysis comparing baseline scores with follow-up postprocedural PROMIS scores was performed. The percentage of patients reporting improvement greater than the minimal clinically important difference (MCID) was calculated for responders and for the worst case scenario.

Results: 179 patients met inclusion criteria. PROMIS PI at 3-, 6-, and 12-month follow-up statistically improved by 1.5 (95 % confidence interval [CI] 1.4-1.6; p = 0.02), 1.5 (95 % CI 1.4-1.6; p = 0.03) and 1.7 (95 % CI 1.6-1.8; p = 0.4), respectively. Follow-up PROMIS PF at 3-month follow-up improved by 1.6 (95 % CI 1.5-1.7; p = 0.04) but did not significantly differ at 6- or 12-month follow-up. The percentage of patients that exceeded MCID thresholds of clinical significance was 44 % (95 % CI 36%-53 %) at 3-months, 49 % (95 % CI 39%-59 %) at 6-months, and 54 % (95 % CI 41%-66 %) at 12-months. Worst case scenario analysis demonstrated that 32 % (95 % CI 36%-53 %) of patients exceeded the MCID thresholds at 3-months, 31 % (95 % CI 24%-37 %) at 6-months, and 21 % (95 % CI 15%-27 %) at 12-months.

Discussion/conclusions: Our study demonstrated that CIESI leads to an improvement in function and pain for patients with cervical radiculopathy. This study was limited by retrospective design, loss to follow-up, and variation in steroids used.