Failed Back Surgery Syndrome: a pilot study of preliminary chronic pain patterns in fMRI data

Abstract

Introduction: Failed Back Surgery Syndrome (FBSS) is a condition of persisting low back pain with or without lumbosacral radiculopathy after 1 or more spine surgeries. Main preoperative risk factors are depression, [than 6 months continuous pain and preexisting neuropathic pain. Spine surgery in chronic low back pain has poor results because of the central sensitization at the level of spinal cord and the ,,pain matrix‘‘of the central nervous system. The main clinical application of pain fMRI would be to contraindicate surgery as a treatment method for patients with altered pain perception and functional brain activity. Cases: To investigate the pain functional consequences, we recorded resting state fMRI followed by block design pain stimulation in FBSS patient with chronic low back pain and neurotypical control who matched in age and sex. Pain stimulus was given via clip compressing distal phalanx of right-hand index finger. The fMRI was performed with GE Optima 450w 1.5 T scanner. fMRI images were analysed with SPM12. We studied the difference in pain activations and resting state between both participants. The threshold for functional activity was selected as 30 voxels (p = 0.001). Pain activations showed differences in FBSS patient: anterior and posterior right insular cortices (IC), both supplementary motor areas (SMA), left primary visual cortex (V1) and both sides of the occipital middle-inferior gyri. Discussion: The diagnostic approach of chronic pain patterns using fMRI could help preventing FBSS. With further larger case–control study research we seek to develop an evident model of chronic pain activation for diagnostic purposes.