The treatment of chronic back pain with sciatica is still an unsolved therapeutic challenge. Percutaneous minimally invasive neurolysis according to the Racz technique is increasingly applied and discussed controversially. So far there is no prospective randomized controlled study for evaluation of a possible treatment effect. In a prospective pilot study, 25 patients with monosegmental radiculopathy of the lumbar spine were treated with minimally invasive percutaneous epidural neurolysis according to Racz's technique. They all suffered from chronic disc herniations or failed back syndromes after surgery, all with radiculopathy. The average age of the patients was 51+/-16 years, the average duration of the symptoms was 28 months. Twelve weeks after the procedure patients had significant clinical improvement. The Oswestry score increased from 64+/-17 to 22+/-12 points. Subjective pain sensation according to the McNab score showed improvement too. None of the patients had worsening of the situation compared to preoperative findings. No clinically relevant complications were observed. The results are being used to design a clinical trial in accordance with good clinical practice guidelines to analyze the therapeutic efficacy of the procedure. The described technique is still a clinically experimental procedure. However, due to a low probability of side effects and due to the good results reported so far by most authors, the Racz catheter technique may be applied in certain patients with chronic radiculopathy refractory to conservative treatment.