Usefulness of posterolateral transforaminal approach in lumbar radicular pain

Abstract

Objective: To compare the short-term effects and advantages of transforaminal epidural steroid injection (TFESI) performed using the conventional (CL) and posterolateral (PL) approaches.

Method: Fifty patients with lumbar radicular pain from lumbar spinal stenosis and herniated lumbar disc were enrolled. Subjects were randomly assigned to one of two groups (CL or PL group). All procedures were performed using a C-arm (KMC 950, KOMED, Kwangju, Kyunggi, Korea). We compared the frequency of complications during the procedure and the effects of the pain block between the two groups at 2, 4, and 12 weeks after the procedure.

Results: There were no significant differences in the demographic data, initial VNS (Visual numeric scale), or ODI (Oswestry disability index) between the CL group (n=26) and the PL group (n=24). There was no statistically significant difference in the outcome measures (VNS and ODI) between the groups at 2, 4, or 12 weeks. Symptoms of nerve root irritation occurred in 1 case of the CL group and in 7 cases of the PL group (p<0.05). Pricking of spinal nerve during the procedure and transient weakness after the procedure occurred in 6 cases and 3 cases, respectively in the CL group, but did not occur in the PL group.

Conclusion: Our findings suggest that the posterolateral approach represents an alternative TFESI method in cases with difficult needle tip positioning in the anterior epidural space, and could lower the risk of target nerve root irritation and nerve penetration.

Keywords: Conventional; Injection; Posterolateral; Transforaminal.

Fig. 1

(A) Anterior-posterior view of the lumbar spine, with superimposed line (1) bisecting the pedicle. This line was drawn halfway between the farthest medial (2) and farthest lateral (3) points on the pedicle. (B) Lateral view of the lumbar spine, with the quadrant system superimposed. First, a line was drawn tangent to the curve of the spine at the level of interest along the posterior vertebral line. (1) A second line (2) was drawn parallel to a this at the posterior margin of the foramen. Next, 2 lines perpendicular to lines 1 and 2 were drawn at the superior and inferior margins of the foramen (3 and 4, respectively). Finally, line (5) was drawn bisecting 1 and 2, and likewise line (6) bisecting 3 and 4. This divided the foramen into 4 quadrants. Arrow: needle position.

Fig. 2

C-arm guided posterolateral approach. (A) AP fluoroscopic image confirms needle position just farthest inferior-lateral of pedicle. (B) Lateral view shows the needle located in the posterior and superior of the intervertebral foramen. (C) Needle was placed adjacent to the L4 nerve root. Contrast injection observed with AP view confirms epiradicular location of the needle's tip with contrast tracking along the nerve as well as entering the epidural space locally.

Fig. 3

Comparative response from VNS preinjection, 2 weeks, 1 month, 3 months for conventional approach and posterolateral approach. ^*Statistically significant at p<0.05 within groups.

Fig. 4

Comparative response from ODI preinjection, 2 weeks, 1 month, 3 months for conventional approach and posterolateral approach. ^*Statistically significant at p<0.05 within groups.