Comparison of contrast flow and clinical effectiveness between a modified paramedian interlaminar approach and transforaminal approach in cervical epidural steroid injection

Abstract

Background The different methods of cervical epidural injection include the median or paramedian interlaminar (PI) approach and the transforaminal (TF) approach. We hypothesized that the modified PI (mPI) approach could deliver drugs suitably and safely into the anterior epidural space compared with the TF approach. Methods A total of 62 patients were randomized into either the mPI group (n=31) or the TF group (n=31). Contrast to the anterior epidural space (primary outcome, grade 1-3), vascular uptake and discomfort were assessed. Furthermore, pain intensity in the arm and neck [numeric rating scale (NRS)] and the degree of symptoms (5-point Likert scale) before the procedure and 2 weeks, 1 and 3 months following the procedure were compared between two groups. Effectiveness (a secondary outcome) was defined as a ≥50% reduction on the NRS for arm and neck pain and a result of 3 or 4 on the Likert scale at 3 months following the procedure. Results Contrast to the anterior epidural space in the mPI group was significantly greater than that in the TF group (P=0.036). Vascular uptake and discomfort in the mPI group were significantly lower than those in the TF group (P<0.001, respectively). Of the patients in whom the procedure was effective, 24 (77.4%) were from the mPI group and 20 (64.5%) were from the TF group (P=0.263). Conclusion This result suggests that the mPI approach allows for suitable and safe delivery of drugs into the anterior epidural space.