Clinical and Radiological Predictors of Response to Lumbar Transforaminal Epidural Steroid Injection at 3 Months: A Retrospective Study

Background: Transforaminal epidural steroid injection (TFESI) is commonly used to relieve pain due to intervertebral disc displacements (IDD). Poorly defined selection criteria lead to post procedure dissatisfaction among patients. We aimed to find clinical and magnetic resonance imaging (MRI) predictors for pain relief at 3 months following a TFESI. Poorly defined selection criteria lead to post procedure dissatisfaction among patients.

Methods: A retrospective study of 116 patients who had undergone TFESI. Predictors used were - age, duration of symptoms, body mass index, neuropathic character of pain, dermatomal distribution of pain, claudication distance, response to anti-neuropathic medication and extent of nerve root compromise in MRI as per Pfirmann criteria. A relief of 50% or more at the end of 3 months was considered the criterion for significant pain relief from TFESI.

Results: At 3 months, 72% (84/116) had significant pain relief. Dermatomal distribution of pain (73%) and neurogenic claudication (71%) were the most prevalent clinical features. Dermatomal distribution of leg pain, responsiveness to anti-neuropathic medications and a Pfirmann grade 2/3 in MRI were the most important predictors with an odds ratio (OR) of 12.1,  ​< ​0.001, OR 6.4,  ​= ​0.002 and OR 3.1,  ​= ​0.056, respectively. The model was statistically significant χ (3, N ​= ​116) ​= ​43.43, 0.001 and explained 52% variance in the outcome. The model correctly predicted the outcome 85% times.

Conclusions: If a patient has leg pain which is dermatomal in distribution, responds to anti-neuropathic medications and has Pfirmann grade 2/3 in MRI, then chances of more than 50% relief persisting at 3 months after TFESI are significantly better.