Comparison of the temporary diagnostic relief of transforaminal epidural steroid injection approaches: conventional versus posterolateral technique

Abstract

Background and purpose: Conventional transforaminal epidural steroid injection (TFESI) has several problems. The purpose of this study was to compare the temporary diagnostic relief and advantages of TFESI performed using the conventional and posterolateral approaches.

Methods: From August to December 2004, 187 patients received TFESI for lumbar radicular pain. A total of 108 patients (65 women, 43 men; mean age, 56 years) fulfilled the inclusion criteria. In essence, the needle target point was the "safe triangle," but if there was a possibility that the needle could penetrate the nerve root or that the injectate could contact spinal nerve, posterolateral TFESI was used as an alternative. Image analyses of needle positions and chart reviews were performed. Logistic regression analysis and t test were used for statistical analysis.

Results: Of the 108 patients, 75 (69.4%) showed an improvement at 2 weeks after TFESI. In 46 patients (42.6%), the needle was located in the posterolateral epidural space, and 33 (71.7%) of those experienced pain relief. Of the 62 patients in whom the needle was located in the anterior epidural position, 42 (68%) experienced pain relief. There was a significant reduction in pain sense for the posterolateral approach (P < .05). However, no statistical difference was found between the 2 approaches and temporary diagnostic relief, and no correlation was found between the other variables tested and temporary diagnostic relief (P > .05).

Conclusion: Our findings suggest that the posterolateral approach is an alternative method for TFESI in cases where needle tip positioning in the anterior epidural space is difficult.

Fig 1.

Schematic description of the “safe triangle” for the conventional TFESI technique. The triangle is composed of a roof made up by the pedicle, a tangential base corresponding to the exiting nerve root, and the lateral border of the vertebral body. ST, safe triangle.

Fig 2.

Schematic description of the conventional and posterolateral TFESI techniques. In oblique view (A), the needle tip is located in the safe triangle using the conventional technique, and the median inferior margin of pedicle with posterolateral approach. The needle appears end-on in this view. Lateral view (B) shows the needle located in the anterior and superior aspect of a nerve root using the conventional technique and at the posterior aspect using the posterolateral technique. C, conventional TFESI; PL, posterolateral TFESI.

Fig 3.

Bar graph showing the number of patients with respect to temporary diagnostic relief according to the 5-point patient outcome scale when interviewed 2 weeks after TFESI. G0 = 0 (aggravated), G1 = 1 (stationary), G2 = 2 (improved), G3 = 3 (much improved), G4 = 4 (no residual symptom).

Fig 4.

A 68-year-old female patient with chronic pain of the anterior aspect of the right leg and a tingling sensation in the L4 dermatome. MR imaging (not shown) showed degenerative spondylolisthesis at the L3/4 level with foraminal stenosis. There was no pain relief in follow-up of 2 weeks after a conventional transforaminal epidural steroid injection (TFESI) at the L3 level.

Fig 5.

A 26-year-old female patient with acute onset radiculopathy in the L3 dermatome. A left paracentral disk protrusion was observed at the L3/4 level in MR images (not shown). A lateral fluoroscopic view showing the needle tip positioned in the posterior aspect of the neural foramen and contrast filling into the posterolateral epidural space. The patient had no pain 2 weeks after posterolateral TFESI of L3.