Evaluation of transforaminal epidural steroid injections for discogenic axial lumbosacral back pain utilizing PROMIS as an outcome measure.

Background Context: Discogenic lumbosacral back pain continues to present a challenging clinical entity with limited, controversial therapeutic options. No study to date has evaluated the efficacy of fluoroscopically guided transforaminal epidural steroid injections (TFESI) in a homogenous patient population with axial lumbosacral back pain from discogenic pathology utilizing strict, explicitly clinical and radiographic criteria. Additionally, there is a paucity of published data utilizing Patient Reported Outcome Measurement Information System (PROMIS) scores as an outcome measure for interventional spine procedures.

Purpose: Evaluate the therapeutic effect of TFESIs in a specific subset of patients with discogenic axial lumbosacral back pain. Investigate PROMIS as an outcome measure for interventional spine procedures targeting focal degenerative spinal pathology.

Study Design/setting: Retrospective review of patients presenting to a multidisciplinary, tertiary academic spine center.

Patient Sample: Three thousand eight hundred eighty-one patients were screened for inclusion. A total of 26 patients with discogenic axial low back, based on strict clinical and radiographic criteria, underwent TFESIs. All patients had axial low back pain without radicular pain, ≥3 clinical features of discogenic pain, corroborative radiographic features of active discogenic pathology on lumbar spine magnetic resonance imaging without confounding spinal pathology.

Outcome Measures: PROMIS Pain Interference (PI) v1.1, PROMIS Physical Function (PF) v1.2/v2.0, and PROMIS Depression (D) v1.0 outcome scores were collected at baseline and postprocedure follow-up.

Methods: Query of an institutional, patient reported outcome database and subsequent retrospective review of electronic medical records was performed. Statistical analysis comparing baseline and postprocedural PROMIS outcome scores and correlation between these instruments was performed. Additionally, an exploratory investigation of minimal clinically important difference achievement rates was performed.

Results: Analysis determined a statistically significant improvement in PROMIS PI (p=.017, 95% CI=-8.02 to -1.82) and PROMIS PF (p=.003, 95% CI=0.91-8.72) scores after treatment with TFESIs. At post treatment time points, TFESI had medium effect size on pain (d=0.55) and function (d=0.59). Change in PROMIS D scores (p=.488, 95% CI -1.74-3.54; d=.08) did not demonstrate statistical significance. Pearson correlation demonstrated a moderate negative correlation (r=-0.544, p=.004) between PROMIS PF with PROMIS PI. Correlation between PROMIS PF (r=-0.239, p=.24) and PROMIS PI (r=0.198, p=.33) with PROMIS D was not significant. Fourteen (53.8%) and 9 (34.6%) subjects achieved minimum clinically important difference (MCID) for PROMIS PI and PROMIS PF, respectively. Nine subjects (34.6%) achieved MCID for PROMIS D despite not otherwise reaching statistical significance otherwise.

Conclusions: Utilizing PROMIS as an outcome measure, discogenic axial lumbosacral back pain patients appear to benefit from TFESI in terms of pain and physical function. This study contributes to the growing body of literature utilizing PROMIS scores in patients with clinical sequelae of degenerative spinal pathology; however, prospective studies are needed.