Study: Fibronectin-aggrecan complex may predict lumbar steroid injection results

ORLANDO, Fla. — The presence of fibronectin-aggrecan complex may be able to predict how a patient will respond to an epidural steroid injection performed to treat lumbar disc herniations, according to study results.

In the two patient groups studied, researchers found the presence of fibronectin-aggrecan complex (FAC) affected the improvement of pain scores and Oswestry Disability Index (ODI) scores after a lumbar epidural injection done for lumbar herniation, according to Lisa Huynh, MD.

Huynh received the Best Fellow Abstract Award at the International Spine Intervention Society Annual Meeting, held, for the study.

“Based on this study, we found there was a greater improvement in the NPRS [Numeric Pain Rating Scale] score and ODI score at 6 weeks post epidural injection for the FAC positive group when compared with the FAC negative group,” Huynh said in her presentation. “While there was not a statistically significant improvement in the NPRS score, we still found that presence of FAC in the disc samples of patients with radiculopathy was associated with improvement in disability following epidural steroid injection.”

Complaint: Lumbar radicular pain

Huynh and colleagues conducted a prospective consecutive cohort study which included 63 patients who complained of lumbar radicular pain, who had positive physical exam findings, including sensory deficits in particular nerve roots, and who had an MRI that confirmed the presence of disc herniation that was consistent with the physical exam. They excluded from the study anyone who had a negative MRI, an epidural steroid injection within the last 3 months or the presence of any “red flags” among other individuals who were unsuited for the study.

The patients ranged in age from 20 years to 70 years old; the average age was 43 years; 56% men and 44% women.

Physicians used fluoroscopic guidance and a caudal approach and performed physiologic saline epidural lavage. The lavage sample was collected prior to steroid administration, Huynh said. Baseline ODI and NPRS scores were obtained for each patient in the study at the outset, as well as at 6 weeks after epidural steroid injection.

Groups’ results differed

When Huynh discussed the findings at the meeting, she said, “The ODI score, what we saw in the FAC positive group, there was a 20-point mean improvement compared to the FAC negative group, which was only an 8-point improvement. In the NPRS scale, there was a 40% improvement in the FAC group as compared to only 15% in the FAC negative group.”

However, “There was not a significant improvement in scores when we used both of these as our primary outcomes,” she said.

When Huynh and colleagues further analyzed the results and looked solely at the ODI results, in which a 15 point improvement represented success, they noticed a statistically significant improvement in the ODI score, she said.

“Protein biomarkers such as the fibronectin-aggrecan complex may be an effective predictor of response to epidural steroid injections. FAC has been previously shown to predict successful response to ESI (epidural steroid injection). In our study, we found while FAC did not predict pain outcomes after ESI, it predicted disability outcomes. Further studies are needed to elucidate the role of inflammatory biomarkers,” Huynh told Spine Surgery Today. – by Robert Linnehan

Reference:

Huynh L. Does fibronectin-aggrecan complex predict response to epidural steroid injection? Presented at: International Spine Intervention Society Annual Meeting; July 30-Aug. 3, 2014; Orlando, Fla.

For more information:

Lisa Huynh, MD, can be reached at Stanford Interventional Spine Center, 450 Broadway St. Pavilion C, Redwood City, CA 94063; email: lisahyn@gmail.com.

Disclosure: Huynh has no relevant financial disclosures.