Incidence of Unintentional Flow of Contrast into the Facet Joints During Fluoroscopy-Guided Cervical Interlaminar Epidural Injections: A Retrospective Cohort Study

Injection into the Space of Okada during Transforaminal Epidural Steroid Injections

OBJECTIVE

Ensuring medication delivery to the epidural space is crucial for effective transforaminal epidural steroid injections, done by injecting a small amount of contrast at final needle position. The purpose of this study is to illustrate the appearance of contrast flow in the retrodural retroligamentous space of Okada during CT- and fluoroscopically-guided cervical and lumbar transforaminal epidural steroid injections.

DESIGN

This retrospective study will utilize a series of cases to demonstrate contrast within the space of Okada during epidural transforaminal steroid injections.

SETTING

Tertiary medical center.

SUBJECTS

Study subjects are adult patients who underwent transforaminal epidural steroid injection at our institution.

METHODS

Cases were identified utilizing a search engine of existing radiology reports at our institution. Epidural steroid injection procedural reports were searched for the terms "Okada" and "retrodural space." Images from the procedure were reviewed by the authors, all proceduralists with dedicated training in spinal injections, to confirm the presence of contrast within the space of Okada.

RESULTS

This case series illustrates six examples of contrast injection into the retrodural space of Okada during cervical and lumbar transforaminal epidural steroid injections.

CONCLUSIONS

Contrast uptake in the retrodural space of Okada may be seen during transforaminal epidural injections. Although relatively uncommon, this is likely underrecognized. It is extremely important that providers who perform transforaminal epidural steroid injections be familiar with this non-epidural contrast flow pattern so that they can adjust needle positioning in order to deliver steroid to the epidural space.