Significant differences of brain blood flow in patients with chronic low back pain and acute low back pain detected by brain SPECT

Background: The aim of this study was to examine and compare the areas of brain blood flow in patients with chronic low back pain (CLBP) without structural abnormality and acute low back pain (ALBP) with lumber disc herniation (LDH). Functional neuroimaging studies provide evidence of abnormalities in the regional cerebral blood flow during low back pain. Recent studies have shown that CLBP is associated with plastic, pathophysiological changes in the brain. However, there has been no report yet statistically or by neuro-images on the compared brain single photon-emission computed tomography (SPECT) findings between CLBP and ALBP patients. Methods: The subjects comprised 14 patients, 7 CLBP and 7 ALBP patients. The CLBP group included the patients who had no or minor structural abnormality in the lumbar spine on magnetic resonance imaging (MRI) and met the criteria for a classification of "pain disorder" (chronic) according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision. The ALBP group included the patients who had symptoms within 3 months of onset and LDH revealed by MRI. All patients were assessed using brain SPECT. We then performed a two-tailed view analysis using the easy Z score imaging system, determined the mean Z scores, and performed vBSEE software (Fujifilm RI Pharma, Tokyo, Japan) for both CLBP and ALBP patients. Results: The CLBP group showed significantly reduced blood flow in the bilateral prefrontal cortex of the frontal lobe and increased blood flow in the bilateral posterior lobe of the cerebellum. Conclusions: SPECT images and statistical analyses revealed the brain blood flow alterations in the patients with ALBP and CLBP. These results may suggest that the dysfunction of the prefrontal cortex could lead to the appearance of unconscious pain behavior controlled by the cerebellum in the patients with CLBP.