SPECT identifies patients best suited for facet injections

Bone scintigraphy can pick the right candidates for a specific type of low back pain treatment, according to a study in the February issue of Radiology. The SPECT-based imaging strategy may lead to significant cost savings.

"Bone SPECT can help identify the patients with low back pain who would benefit from facet joint injections," said principal investigator Dr. Spiros G. Pneumaticos, an assistant professor of orthopedic surgery at Baylor College of Medicine in Houston.

Patients with negative bone SPECT should be spared this treatment, he said.

Chronic low back pain tops the ranking of work-related disability ailments and contributes largely to job-related absenteeism in the U.S., according to the National Institute of Neurological Disorders and Stroke. Degenerative changes in the spine often cause the condition, which is commonly treated by steroid and anesthetic injections to the facet joints of the spine.

SPECT pinpoints abnormal cell activity in the spine, which helps nuclear medicine physicians identify the culprits for patients' symptoms.

Pneumaticos and colleagues studied 47 patients with low back pain who were scheduled for facet joint injection. Patients were randomly divided into two groups: one that underwent bone SPECT prior to injection (A) and another that did not (B). Patients showing positive SPECT results underwent focalized treatment in the lumbar spine area highlighted by scintigraphy (subgroup A1). Patients showing no facet joint abnormality on SPECT (A2) as well as those in group B received injections as indicated by the referring physicians.

Patients in subgroup A1 showed a significantly higher reduction in pain than the other patients after one month of treatment. Only 27 facets in this subgroup required injection compared with the 60 facets the referring physicians recommended. The overall Medicare cost reduction per patient was $326.

"Facet joint injection can be a good short-term treatment alternative in some patients, but these injections don't help all patients, are relatively expensive, and can cause complications," Pneumaticos said.

Physicians have had no reliable way until now to determine which patients will actually benefit from these injections. The study showed that patients respond well to treatment when injected at the site of abnormalities seen on SPECT. Conversely, patients with a negative SPECT have a much smaller chance of improving, he said.

"This study shows that a relatively simple test can help identify patients who will benefit. This helps avoid the use of facet injections in patients who would not benefit or could possibly be hurt by the procedure," he said.

For more information from the Diagnostic Imaging archives:

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Functional MRI zeroes in on back pain