The effectiveness of a pulsed radiofrequency treatment on radicular neuropathic pain.

Chronic radicular neuropathic pain originating from lumbar or sacral nerve root is a common neuropathic pain and in some cases diffult to treat. Currently PRF is applied on the DRG to patients with refractory radicular neuropathic pain. The effectiveness of a PRF treatment is currently determined by a VAS score. A VAS score is subjective. A more subjective measurement of pain is desired, this can be by means of electric quantitative sensory testing (eQST). The aim of the research is to study the effectiveness of PRF treatment on radicular neuropathic pain and to study if the eQST is more accurate and reliable than the VAS score.

8 weeks after the PRF treatment we expect that the electric quantitative sensory testing (eQST) values are higher compared to the eQST values before the PRF treatment. This means that patients can tolerate a higher stimulation threshold. The difference in eQST values between the eQST before treatment en 8 week after treatment, will be higher compared to the difference in eQST values for the shamtreatment where only lidocaine is injected.

The eQST and VAS score will be performed after the diagnostic block. When the diagnostic block is positive (> 50% pain reduction), the patient will be randomised for or the lidocaine treatment or the PRF treatment. Before the treatment the eQST will be performed. The patient handed in the pain detect questionnaire, VAS score, RAND-36 questionnaire and HADS questionnaire. Furthermore the medication use will be noted.
After the treatment the VAS score and eQST will be performed.

After 1 week, 8 weeks, half year and a year after the treatment the patient handed in pain detect questionnaire, VAS score, RAND-36 questionnaire, medication use and the eQST will be performed. 1 week after the treatment the patient does not handed in the RAND-36 questionnaire.

The intervention which will be studied is Pulsed radiofrequency treatment (PRF) on the dorsal root ganglion (DRG) by patients with radicular neuropathic patients. PRF uses radiofrequency current in short (20 ms), high-voltage bursts; the “silent” phase (480 ms) of PRF allows time for heat elimination, generally keeping the target tissue below 42° C for 120 seconds. During the PRF treatment lidocaine will be injected.



The control intervention which will be studied is lidocaine treatment. During this treament lidocaine will be injected. It will be performed as same as the PRF treament whitout the radiofrequency current.



The effectiveness will be determined by electric quantitative sensory testing (eQST).
sQST consisted of determining thresholds to transcutaneous constant current electric stimulation. eQST values will be determined before PRF/sham treatment, after treatment, 1 week, 8 weeks, half year and a year after treatment.