Parivash SN, et al. - Between November 2009 and November 2015, images from cases of cervical interlaminar epidural steroid injection under CT fluoroscopic guidance performed at a single institution were collected and analyzed in order to to evaluate the rate of inadvertent injection into the retrodural space of Okada during CT fluoroscopy–guided interlaminar epidural steroid injection in the cervical spine. During cervical interlaminar epidural steroid injection, a 2.9% rate of unintended injection into the retrodural space of Okada was identified. Findings suggested that these nontarget injections could result in treatment failure in a subset of patients who undergo cervical interlaminar epidural steroid injection if unrecognized.