CT a justifiable choice over fluoroscopy for guiding spinal injections

Along with confirming CT as a fast and relatively low-radiation means of guiding epidural steroid injections for pain relief in the spine, researchers in New York City have shown CT guidance similarly safe and speedy for other back-pain interventions like injections to nerve roots and facet joints.

Matthew Lazarus, MD, PhD, of Montefiore Medical Center and colleagues from Albert Einstein College of Medicine published their findings in the May/June edition of Pain Physician.

In introducing their work, the authors note that CT has advantages over conventional fluoroscopy, including improved anatomic localization and use of air for contrast. However, concerns remain over CT possibly bringing higher radiation doses and longer procedure times.

To test the grounding of these concerns, the team reviewed 994 CT-guided spine procedures performed on 699 patients over the course of a year. The interventions included 585 epidural steroid injections, 228 nerve root blocks and 90 facet blocks.

They found that procedure time across all interventions averaged 7:34 ± 5:05, while dose-length product averaged 75 mGy·cm ± 61 and overall effective dose was 1.13 mSv for all procedures.

The authors cite previous studies to show that these times and doses are comparable with spine-pain control procedures guided by conventional fluoroscopy.

Further, they note, their sample sizes for other interventions—lumbar puncture, facet ablation and ganglion block—“demonstrate higher but still acceptable procedure times and radiation dose.”

Also of note, on review of medical records, a high rate of patients turned out to have body mass indexes placing them in the categories of overweight (76 percent) or obese (42 percent), and many had comorbidities such as hypertension (n = 179), diabetes (n = 101) and renal failure (n = 30).

Commenting on this finding, the authors note that CT guidance can be confidently selected for these patients.  

One disadvantage of CT guidance may be its relatively high cost, Lazarus et al. state. CT guidance, they point out, is approximately 0.9 relative value units higher than fluoroscopy. They cite European cost analyses showing CT to be cheaper than MRI guidance for lumbosacral nerve root injection and between ultrasound and MRI guidance for cervical nerve root injection.

“As cost and resources vary by health care facility and geographic location, the scale and potential impact of these differences should be considered in the individualized setting,” the authors write.

They acknowledge as a primary limitation in their study’s design its single-site sample.

“Our findings add to the growing evidence that CT guidance is a safe and effective technique for epidural steroid injection,” Lazarus and colleagues conclude. “These data further demonstrate that other spine intervention procedures can be performed with acceptable procedure time and radiation dose under CT guidance.”