The Incidence of Intradiscal, Intrathecal, and Intravascular Flow During the Performance of Retrodiscal (Infraneural) Approach for Lumbar Transforaminal Epidural Steroid Injections.

BACKGROUND

Lumbar transforaminal epidural steroid injections (TFESIs) are often used in the treatment of radicular pain. In light of safety concerns, many practitioners have proposed adopting the retrodiscal (infraneural) approach with the needle tip positioned into Kambin's triangle. With this technique, the needle may inadvertently be directed too far ventrally and enter the intervertebral disc. In addition, the risk of subarachnoid or subdural extra-arachnoid injection may be higher with this technique as well.

OBJECTIVE

To determine the incidence of inadvertent intradiscal, intrathecal, and vascular injections during the performance of retrodiscal TFESI.

STUDY DESIGN

Retrospective review

METHODS

Retrospective review of all retrodiscal approach TFESIs performed from July 2012 to August 2014 by two of the authors (DL and SH).

RESULTS

A total of 257 retrodiscal transforaminal injections were performed. There were no neurologic complications. There were no cases of discitis. Inadvertent intradiscal injections occurred in 12/257 injections, 4.7% (95% CI 2.1-7.3%). Intrathecal injections occurred in 8/257 injections, 3.1% (95% CI 0.99- 5.23%). Three were subarachnoid (SA), four were subdural extra-arachnoid (SDXA), and one was both SA and SDXA. Vascular injections occurred in 17/257, 6.6% (95% CI 3.6-9.6%).

CONCLUSION

This retrospective review demonstrates that a relatively high rate of inadvertent intradiscal injections occurs in the performance of the retrodiscal approach for TFESI. This has significant implications in terms of the potential risk of disc injury induced by the needle puncture. The high incidence of intrathecal injections may also be of great concern depending upon the injectate delivered.