The changes in thermographic pattern were studied, in patients with persistent back and leg pain after surgery, to validate its significance in evaluating the clinical status following percutaneous radiofrequency (PRF) lesioning on dorsal root ganglion. A total of 90 patients with persistent back and leg (52 males, 38 females, mean age 46.2 years) with more than 6 months of duration following lumbar surgeries were enrolled into study. Thermography was performed before and after PRF procedures. PRF procedures were percutaneously done with C-arm guidance and adjustments from physiologic monitoring. Assessments included the clinical symptoms, signs and changes of thermographic pattern before and after PRF procedure. Minimal follow up period was 6 months. All patients tolerated the RF procedures without complications. Thermographic findings before procedures were agreeable to clinical and radiographic findings in 81(90%) of patients. PRF procedure provided substantial improvement of pain (>50% pain reduction) in 69(76.7%) and 63(70%) at 1 and 6 months following procedures. Thermographic findings in 80(88.9%) of these patients seemed to correlate with clinical improvement. However, 12 patients (13.3%) showed no significant thermographic changes despite clinical improvement. Clinical factors that were not statistically significant but were related to better outcome were younger age, unilateral pain, no significant dysesthesia, less number of operations, no instrumentation. Results of this study indicate that thermography may have a specific role in evaluating these patients, especially when comparing with clinical status.