Table 3 Correlations between age, clinical, imaging and laboratory characteristics of the included patients, and both NRS and FRI 6 months after radiofrequency

Age

0.140

0.333

0.008

0.954

Duration of pain in months

0.438

0.001*

0.611

< 0.001*

Number of prolapsed discs

-0.194

0.176

-0.147

0.308

NRS before radiofrequency

0.299

0.035*

0.366

0.009*

FRI before radiofrequency

0.014

0.922

0.241

0.092

BDNF serum level before radiofrequency in ng/ml

-0.324

0.022*

-0.291

0.041*

S100B serum level before radiofrequency in ng/ml

0.499

< 0.001*

0.469

0.001*