Posterior epidural contrast injection via posterolateral transforaminal approach.

We read the article by Zhu et al (1) regarding an alternative approach for lumbar transforaminal epidural steroid injections. We found that their work was similar to our previously reported article, “Fluoroscopically guided transforaminal epidural dry needling for lumbar spinal stenosis using a specially designed needle” (2). In our article, we introduced a minimally invasive interventional technique using a specially designed needle to treat lumbar spinal stenosis via transforaminal approach. The primary treatment target of our technique was the posterior epidural space. Figure 1 shows our treatment target. Although there were several differences (computed tomography images, needling point, and left-sided approach in ours and magnetic resonance images, injection point, and right-sided approach in theirs), we think basic concepts between the 2 works were similar. We bent the needle 5-30° at a point 2-4 mm from the tip. They used a spinal needle with a pencil tip (a blunted tip) bent 3-5 mm from the tip. We conducted a transforaminal epidural contrast agent injection test using a spinal needle to examine whether the specially designed needle made for our technique effectively reached the posterior epidural space (Fig. 2). We found that when the spinal needle was advanced transforaminally in its original straight form, it was difficult to contact the canal side of the inferior articular process between the facet joint and pedicle and advance further into the anterior epidural space. However, when the tip was curved (Fig. 2A), one could easily contact the canal side of the inferior articular process between the facet joint and pedicle and reach the posterior epidural space (Figs. 2B and 2C). We hope to hear their opinion on what may be similar and what may be different between our approach and theirs.