Just say no … to MRI for sciatica follow-up

MRI spine imaging, perhaps the poster child for overuse, has the dubious distinction of a top five spot on the internal medicine and family medicine lists of most commonly overused tests. Research published March 14 in the New England Journal of Medicine adds fuel to the fire. MRI performed at one-year follow-up in patients treated for sciatica is not linked with improved outcomes, according to the study. An accompanying editorial dubbed follow-up spine imaging for sciatica a “red herring.”

In a previous study, Abdelilah el Barzouhi, MD, and colleagues reported on the results of a trial comparing early surgery for patients with sciatica and a strategy of prolonged conservative care with surgery if needed. The current study addressed MRI findings at one-year and their correlation with clinical outcomes.

MRI findings and sciatica symptoms often don’t sync. Previous research has indicated that MRI shows disk herniation in 20 to 76 percent of asymptomatic patients.

The Sciatica Trial follow-up focused on 131 patients assigned to early surgery and 136 to prolonged conservative care. Patients underwent MRI at baseline and one year after randomization.

Three readers evaluated images for disk contour and presence of herniation, and they scored characteristics of disk herniation. For one-year outcomes, the researchers defined a favorable outcome as complete or nearly complete absence of symptoms based on patient responses to a seven-point Likert scale.

A total of 84 percent of patients reported a favorable outcome at one year. However, patients’ perceptions were not in accordance with imaging findings. Disk herniation was shown in 35 percent of patients with a favorable outcome and 33 percent of those with an unfavorable outcome. Among patients with disk herniation at one-year, 85 percent reported a favorable outcome, compared with 83 percent with no herniation at one year.

“Therefore, patients asking for reimaging because of persistent or recurrent symptoms should be informed about the difficulty of MRI interpretation after a first episode of acute sciatica,” wrote el Barzouhi et al. “Our results show that clinicians should not automatically ascribe recurrent or persistent symptoms to visible scar formation on MRI.”

The researchers called for additional studies to determine the value of MRI in clinical decision making among this population.

The study provides information that can help physicians avoid MRI of patients with persistent sciatica, a situation in which imaging is unlikely to be useful, R.A. Deyo, MD, MPH, from the departments of family medicine, medicine, and public health and preventive medicine at Oregon Health and Science University in Portland, offered in an accompanying editorial. Deyo suggested radiologists add information regarding the variability of findings among normal patients to imaging reports.