An evaluation of contrast dispersal pattern on preganglionic epidural injection through trans-lateral recess approach in patients with lumbosacral radiculopathy

Purpose To evaluate the accessibility of the preganglionic epidural space in patients with lumbosacral radiculopathy treated with epidural steroid injection (ESI) through trans-lateral recess (TLR) approach. Methods From September 2016 to December 2016, we enrolled 50 consecutive preganglionic ESI through TLR approach for 38 patients with lumbosacral radiculopathy at or below L4 territory. Fifteen of patients were diagnosed with lumbar disc herniation and 23 with lumbar spinal stenosis. TLR epidural injection was performed with 20-G Tuohy needles. To achieve proper final needle placement (i.e., in the axillary portion between the exiting and transversing nerve roots), the needle direction was set laterally from the center of the infra-adjacent spinous process to the medial wall of the corresponding pedicle and superiorly from the distal tip of infra-adjacent spinous process to the corresponding vertebral foramen. Finally, 1 mL of contrast was injected to assess the epidurographic pattern. Results All patients achieved filling of the dorsal and ventral epidural space. Rostral spreading along the exiting nerve root to the foramen of target segment was present in 48/50 (96%) patients and caudal spreading along the transversing nerve root to the foramen of lower segment in 45/50 (90%) patients. No intravascular injection or dural puncture-related neural complications were observed. Conclusions When delivered using the TLR approach, epidural injections result in excellent drug spread within the preganglionic area (i.e., ventral epidural contrast filling and periradicular infiltration of exiting and transversing nerve roots). As noted previously that higher rates of pre-ganglionic epidural infiltration might be led to improvements in clinical pain and disability, epidural injections delivered using the TLR approach are expected to complement existing epidural modalities. Graphical abstract These slides can be retrieved under Electronic Supplementary Material.