Targeted Steroid Injection Via Epidural Catheter vs Standard C7-T1 Approach for Radicular Pain

Avoiding the risks of cervical interlaminar epidural steroid injection, using a targeted epidural catheter.
Avoiding the risks of cervical interlaminar epidural steroid injection, using a targeted epidural catheter.

Results of a randomized trial published in Regional Anesthesia and Pain Medicine show no significant difference in outcomes between a standard cervical interlaminar epidural steroid injection (CIESI) at C7-T1 and CIESI with a targeted epidural catheter for the treatment of cervical radicular pain.1

In treating cervical radicular pain with epidural steroid injection, the transforaminal approach allows direct delivery of the steroid into the nerve root. However, it carries the risk of thromboembolism or injury to the vertebral or radicular artery.2,3 While the CIESI avoids these arteries, it “limits our ability to inject at high levels because the epidural space becomes narrow, such that dural puncture or direct spinal cord trauma are possible consequences,” explained principal investigator Zachary McCormick, MD, an assistant professor of physical medicine and rehabilitation in the department of orthopaedic surgery at the University of California, San Francisco.4,5

The alternate approach of CIESI with epidural catheter advancement to the level and side of pathology “allows for a safe level of access, yet targeted deposition of medication in close proximity to the affected nerve root,” Dr McCormick told Clinical Pain Advisor. “While this technique provides theoretical appeal, its clinical effectiveness had never been compared to the standard C7-T1 CEISI approach.” The current research aimed to compare the 2 techniques in 76 participants (59% female) at an academic pain center.

In this single-blind prospective study, patients with radicular pain at the C4, C5, or C6 level were randomly assigned to 1 of the 2 treatments: targeted CIESI or standard C7-T1 CIESI. Assessments were conducted before the initial injection and at follow-up sessions at 2 weeks and 1, 3, and 6 months, which included the following measures: Numerical Rating Scale (NRS) for pain, Oswestry Neck Disability Index (ONDI), Pain Disability Index (PDI), McGill Pain Questionnaire (MPQ), Patient Global Impression of Change (PGIC), daily morphine equivalents (DME), and Medication Quantification Scale (MQS) III scores. NRS scores at 1 month represented the primary study outcome, while the remaining measures were the secondary outcomes.

Both groups showed significant improvements in pain, function, disability, and medication use, which remained at the 6-month follow-up assessment. No intergroup differences in primary or secondary measures were observed at any of the follow-up intervals. At 1 month, a 50% or greater NRS reduction was found in 72% of the catheter group (95% confidence interval [CI], 57%-87%) and 60% of the no-catheter group (95% CI, 45%-75%).

“While outcomes of the catheter-based approach were superior across nearly all categories of assessment, these differences did not reach a level of statistical significance,” according to Dr McCormick. A larger study would be required to confirm the possible superiority of the cathether-based approach, and further investigation comparing the effectiveness of the 2 techniques for higher-level radicular pain syndromes is needed. While most of the participants had either C5 or C6 radicular pain, he notes that in theory, the “catheter-approach may be more valuable for even higher level pathology, in which the site of inflammation and/or nerve root irritation is further from the site of medication deposition when using the standard C7-T1 approach.”

Summary and Clinical Applicability

In a new study of patients with cervical radicular pain, no significant difference in outcomes was found between a standard cervical interlaminar epidural steroid injection (CIESI) at C7-T1 and CIESI with a targeted epidural catheter.

Limitations and Disclosures

Limitations: The sample's heterogeneity in symptom duration and imaging results may present a limitation, though the differences were not significantly different between groups.

Conflicts of Interest: The authors state that they have no conflicts of interest to report. 

 

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References

  1. McCormick ZL, Nelson A, Bhave M, et al. A prospective randomized comparative trial of targeted steroid injection via epidural catheter versus standard C7-T1 interlaminar approach for the treatment of unilateral cervical radicular pain. Reg Anesth Pain Med. 2017; 42(1):82-89.
  2. Engel A, King W, MacVicar J; Standards Division of the International Spine Intervention Society. The effectiveness and risks of fluoroscopically guided cervical transforaminal injections of steroids: a systematic review with comprehensive analysis of the published data. Pain Med. 2014; 15(3):386-402.
  3. Huntoon MA. Anatomy of the cervical intervertebral foramina: vulnerable arteries and ischemic neurologic injuries after transforaminal epidural injections. Pain. 2005; 117(1-2):104-111.
  4. Hogan QH. Epidural anatomy examined by cryomicrotome section: influence of age, vertebral level, and disease. Reg Anesth. 1996; 21:395-406.
  5. Lirk P, Kolbitsch C, Putz G, et al. Cervical and high thoracic ligamentum flavum frequently fails to fuse in the midline. Anesthesiology. 2003; 99(6):1387-1390.
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