Fig. 3.

Clinical studies on CPSS treatment. Recent clinical studies of CPSS were categorized according to the proposed algorithm and the levels of evidence. These studies were mainly randomized controlled clinical trials over the past 20 years, excluding those using the combined treatment and studies classified as Level V evidence. CPSS, chronic pain after spine surgery; LDH, lumbar disc herniation; CFT, cognitive functional therapy; MBRS, mindfulness-based stress reduction; NSAID, nonsteroidal anti-inflammatory drugs; SCS, spinal cord stimulation; HF-SCS, high-frequency 10 ​kHz SCS; DRGS, dorsal root ganglion stimulation; IDDS, intrathecal drug delivery system; MDT, microdiscectomy [[60], [61], [62], [63], [64], [65], [66], [67], [68], [69]].