Inadvertent Intrafacet Injection during Lumbar Interlaminar Epidural Steroid Injection: A Comparison of CT Fluoroscopic and Conventional Fluoroscopic Guidance

Abstract

BACKGROUND AND PURPOSE: Inadvertent intrafacet injection can occur during interlaminar epidural steroid injection, resulting in a false-positive loss of resistance and nontarget injection of medication. The purpose of this investigation was to compare the observed rates of this phenomenon during lumbar interlaminar epidural steroid injection performed by using conventional fluoroscopic and CT fluoroscopic guidance.

Case series of fluoroscopic findings and 3D reconstruction of human spinal MRIs of the space of Okada

“…Higher‐quality CT and MRIs have been obtained (Kim et al, 2018; Lehman et al, 2015; Reina et al, 2016), but the exact description of the space remained unclear. CT guidance (Kranz et al, 2017; Lehman et al, 2015; Murthy et al, 2011) allowed researchers to view the spread of the injected solution and details of the vertebrae, but it did not provide details of the retrodural spaces. Our 3D model, however, uses a configuration that enables us to perform 3D reconstruction to accurately identify the boundaries of all of the soft‐tissue structures related to the space of Okada by intentionally modifying the standard voxel shape to an isometric voxel shape.…”

“…False-positive rates of loss of resistance were as high as 25 to 30% when using air-filled syringes to enter the epidural space for an interlaminar epidural steroid injection (Tran et al, 2016). Furthermore, the space of Okada has been demonstrated in 80% of the population at the cervical spine with arthrograms (Okada, 1981), whereas it was estimated to be present at the lumbar area in 7.5% of the population (Kranz et al, 2017). The question that remains to be answered by further research is whether some of these failures of epidural blocks could be attributed to unrecognized entry into the retrodural space of Okada and whether it is possible to place an epidural catheter into this space.…”

“…Later, this space was demonstrated radiologically in the lumbar spine as well, although in fewer cases (Lehman, Murthy, Diehn, Verdoorn, & Maus, 2015). The reported occurrence depended on the sensitivity of the imaging technique (Kranz, Joshi, Roy, Choudhury, & Amrhein, 2017); it was demonstrated in 0.6 to 1.2% of cases when conventional fluoroscopy was used and in 7.5% of cases when computed tomography (CT) fluoroscopic guidance was used (Kranz et al, 2017).…”

Direct Visualization of Cervical Interlaminar Epidural Injections Using Sonography

“…False-positive LOR occurs in 29.4% of patients who undergo CEDI under conventional fluoroscopic guidance [ 7 ]. The retrodural space of Okada is a potential space dorsal to the ligamentum flavum that allows communication between the bilateral facet joints and interspinous bursa [ 8 , 21 , 22 ]. In the current study, the space of Okada on the ligamentum flavum was visible using US ( Figure 5 , Video S3 ).…”

The retrodural space of Okada and its relevance to CT guided intervention

“…While well described in the cervical spine, 3 the retrodural space has also been demonstratedalbeit less frequentlyin the lumbar spine. 4,5 The retrodural space extends from the foramen magnum cranially to the sacrococcygeal membrane inferiorly, bounded laterally by the facet joint capsules and articular facets, anteriorly by the ligamentum flavum and posteriorly by the interspinous ligament and spinous process (Fig. 1).…”