Spinal cord stimulation (SCS) is one of the most commonly undertaken neuromodulatory surgery techniques in the treatment of neuropathic pain. The indication for SCS is an ineffective conservative treatment of chronic pain syndromes. The effectiveness of SCS in the case of neuropathic pain is high. The positive result of SCS treatment is the reduction of previous painful symptoms by min. 50% and / or a reduction in the amount of taken analgesics and an improvement in the quality of life including sleep quality. Long-term studies estimate that in a properly selected group of patients more than 50% of patients achieve pain reduction by the required 50% and about 60% - 70% have an improvement in the quality of life and a reduction of pain.

The efficacy of SCS in different modes of stimulation is evaluated. Patients receive four different types of stimulation for 2-week period - not knowing what kind of stimulation it is. It is said that in one type of stimulation they would feel parestesias and in other three they would not. Patients are not informed that beside tonic, burst and high frequency stimulation, the fourth is an off stimulation to check for placebo effect. The test is double-blinded

Patients with FBSS and CRPS are evaluated for VAS,, dissability scale, Quality of Life (QoL), sleep disorders and mental disorders.

All patients undergo percutaneus (1 or 2) 8-contact SCS electrode implantation with trial.

All patients are blindly randomized to tonic or burst or high frequency or off stimulation. After 2-week period each participant is adequately switched to another type of stimulation for next 2 weeks. Alltogether crossover takes 8 weeks: four 2-week periods of tonic, burst, HF and off stimulation. At the end of trial period patients are subjected to the mode of stimulation which is the most efficent. The final 2-week stimulation is performed with final renewed evaluation for VAS, amount of taken medications, dissability scale, Quality of Life (QoL), sleep disorders and mental disorders. Follow-up observation will last up to 12 months.

Inclusion Criteria:

1. FBSS, CRPS patients with neuropathic and mixed pain in low-back and/or legs refractory to conservative therapy
2. Chronic pain as a result of FBSS that exists for at least 6 months
3. ≥ 18 years of age
4. Written consent of the patient to participate in study procedures.

Exclusion Criteria:

1. Active malignancy
2. Addiction to any of the following: drugs, alcohol and/or medication
3. Evidence of an active disruptive psychiatric disorder or other known condition significant enough to impact perception of pain, compliance to intervention and/or ability to evaluate treatment outcome as determined by investigator
4. Local infection or other skin disorder at site of surgical incision
5. Pregnancy