Incidence of inadvertent intra-articular lumbar facet joint injection during fluoroscopically guided interlaminar epidural steroid injection

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

OBJECTIVE

We sometimes encounter unintentional flow of contrast into the facet joints during cervical interlaminar epidural injection, which leads to false-positive epidural injection. The purposes of this study were to evaluate the rate of facet flow of contrast and to investigate various factors associated with injection into the space of Okada during fluoroscopy-guided cervical interlaminar epidural injection.

SETTING AND SUBJECTS

Images from consecutive cases of fluoroscopy-guided cervical interlaminar epidural injection performed at a single institution between July 2015 and July 2018 were obtained and reviewed.

METHODS

Cases of epidural injection were classified as either facet flow or no facet flow. Multivariate logistic regression was used to identify the predictive factors of unintended injection into the Okada space.

RESULTS

A total of 2,006 cases were included. Intra-articular flow was identified in 6.0% of cases (121/2,006). All cases of flow of contrast into the facet joints were recognized, and appropriate epidurograms were obtained during the procedures. The highest rate of unintended facet flow of the contrast (10.1%, 44/436) occurred at C5-6. Cervical interlaminar epidural injection at C5-6 and above (adjusted odds ratio [aOR] = 1.929, P = 0.001) and the paramidline approach for epidural injection (aOR = 2.427, P < 0.001) were associated with injection into the space of Okada.

CONCLUSIONS

We detected injection into the space of Okada during fluoroscopy-guided cervical interlaminar epidural injection in 6.0% of procedures. Cervical interlaminar epidural injection at C5-6 and above and the paramidline approach for epidural injection were positive predictors of unintentional facet flow of the contrast.

Unintentional lumbar facet joint injection guided by fluoroscopy during interlaminar epidural steroid injection: a retrospective analysis

Background

An epidural steroid injection (ESI) is a commonly administered procedure in pain clinics. An unintentional lumbar facet joint injection during interlaminar ESI was reported in a previous study, but there has not been much research on the characteristics of an unintentional lumbar facet joint injection. This study illustrated the imaging features of an unintentional lumbar facet joint injection during an interlaminar ESI and analyzed characteristics of patients who underwent this injection.

Methods

From December 2015 to May 2017, we performed 662 lumbar ESIs and we identified 24 cases (21 patients) that underwent a lumbar facet joint injection. We gathered data contrast pattern, needle approach levels and directions, injected facet joint levels and directions, presence of lumbar spine disease as seen on magnetic resonance images (MRI), and histories of lumbar spine surgeries.

Results

The contrast pattern in the facet joint has a sigmoid or ovoid contrast pattern confined to the vicinity of the facet joint. The incidence of unintentional lumbar facet joint injection was 3.6%. The mean age was 68.47 years. Among these 21 patients, 14 (66.7%) were injected in the facet joint ipsilaterally to the needle approach. Among the 20 patients who received MRI, all (100%) had central stenosis and 15 patients (75%) had severe stenosis.

Conclusions

When the operator performs an interlaminar ESI on patients with central spinal stenosis, the contrast pattern on the fluoroscopy during interlaminar ESI should be carefully examined to distinguish between the epidural space and facet joint.

Spinal Injections for Pain Management

Image-guided spinal injection is commonly performed in symptomatic patients to decrease pain severity, confirm the pain generator, and delay or avoid surgery. This article focuses on the radiologist as spine interventionist and addresses the following four topics relevant to the radiologist who performs corticosteroid injections for pain management: (a) the rationale behind corticosteroid injection, (b) the interaction with patients, (c) the role of imaging in procedural selection and planning, and (d) the pearls and pitfalls of fluoroscopically guided injections. Factors that contribute to the success of a pain management service include communication skills and risk mitigation. A critical factor is the correlation of clinical symptoms with magnetic resonance (MR) imaging findings. Radiologists can leverage their training in MR image interpretation to distinguish active pain generators in the spine from incidental abnormalities. Knowledge of fluoroscopic anatomy and patterns of contrast material flow guide the planning and execution of safe and effective needle placement. ^© RSNA, 2016 Online supplemental material is available for this article.

Fluoroscopically Guided Epidural Injections of the Cervical and Lumbar Spine

Advances in imaging and the development of injection techniques have enabled spinal intervention to become an important tool in managing chronic spinal pain. Epidural steroid injection (ESI) is one of the most widely used spinal interventions; it directly delivers drugs into the epidural space to relieve pain originating from degenerative spine disorders-central canal stenoses and neural foraminal stenoses-or disk herniations. Knowledge of the normal anatomy of the epidural space is essential to perform an effective and safe ESI and to recognize possible complications. Although computed tomographic (CT) or combined CT-fluoroscopic guidance has been increasingly used in ESI, conventional fluoroscopic guidance is generally performed. In ESI, drugs are delivered into the epidural space by interlaminar or transforaminal routes in the cervical spine or by interlaminar, transforaminal, or caudal routes in the lumbar spine. Epidurography is usually performed before drug delivery to verify the proper position of the needle in the epidural space. A small amount of contrast agent is injected with fluoroscopic guidance. Familiarity with the findings on a typical "true" epidurogram (demonstrating correct needle placement in the epidural space) permits proper performance of ESI. Findings on "false" epidurograms (demonstrating incorrect needle placement) include muscular staining and evidence of intravascular injection, inadvertent facet joint injection, dural puncture, subdural injection, and intraneural or intradiscal injection. ^©RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on December 22, 2016.

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

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.

MATERIALS AND METHODS

We retrospectively reviewed 349 lumbar interlaminar epidural steroid injections performed by using conventional fluoroscopy or CT fluoroscopic guidance to determine the observed rates of inadvertent intrafacet injection with each technique. Cases of inadvertent intrafacet injection were classified as either recognized or unrecognized by the proceduralist at the time of the procedure. Multivariate logistic regression was used to determine the independent effect of imaging guidance technique, age, and sex.

RESULTS

The rate of inadvertent intrafacet injection was observed to be 7.5% in the CT fluoroscopic group and 0.75% in the conventional fluoroscopy group. All 16 cases identified from CT fluoroscopic procedures were recognized during the procedure; the single case identified from conventional fluoroscopy procedures was not recognized prospectively. The type of imaging guidance showed a statistically significant effect on the detection of the phenomenon (OR for conventional fluoroscopy versus CT fluoroscopy = 0.10, P = .03) that was independent of differences in age or sex.

CONCLUSIONS

Inadvertent intrafacet injection is identified during CT fluoroscopic-guided interlaminar epidural steroid injection at a rate that is 10-fold greater than the same procedure performed under conventional fluoroscopy guidance.

Fluoroscopically guided lumbar facet joint injection using an interlaminar approach and loss of resistance technique

PURPOSE

To describe a new technique for performing fluoroscopically guided lumbar facet joint injections using an interlaminar approach and loss-of-resistance technique and to report the initial success rate of this technique in a small series of patients.

MATERIALS AND METHODS

The institutional radiology database was retrospectively reviewed to identify patients who underwent fluoroscopically guided lumbar facet joint injections. Between 1 May 2014 and 31 October 2015, one radiologist attempted fluoroscopically guided lumbar facet joint injections using an interlaminar approach and loss-of-resistance technique in ten severely osteoarthritic facet joints (4 patients). Patient demographics, facet joint side and level, and whether or not an intra-articular facet joint injection was achieved were recorded.

RESULTS

Intra-articular injection was achieved using the interlaminar approach and loss-of-resistance technique in five facet joints.

CONCLUSION

Fluoroscopically guided lumbar facet joint injection using an interlaminar approach and loss-of-resistance technique is an alternative approach to a direct posterior facet joint injection and may be particularly useful for severely osteoarthritic facet joints, where bulky osteophytes and/or extreme curvature of the joints in the transverse plane threaten to preclude direct posterior access to the joints.