This section describes efficacy outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.
4.1 A randomised controlled trial of 28 patients treated by percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) of the intervertebral disc nucleus (n=13) or sham (n=15) reported treatment success (defined as a 2‑point reduction on a visual analogue scale [VAS] and pain reduction of 50% or more on a 7‑point global perceived effect scale ranging from much worse [−3] to total pain relief [+3]) in 1 patient in the PIRFT group and in none in the sham group, 12 months after the procedure (no significant difference between groups).
4.2 A case series of 76 patients treated by pulsed radiofrequency reported good clinical success (defined as 50% or more pain reduction on a 10‑point numeric rating scale) in 38% (29/76) of patients at 3 months. It reported moderate clinical success (defined as a minimum of 2 points reduction in pain intensity) in 30% (23/76) of patients at 3 months. Pulsed radiofrequency had no effect on pain symptoms in 29% (22/76) of patients at 3 months. In the group who had 50% or more pain reduction at 3 months, 79% (23/29) of patients still had this effect at 12‑month follow‑up. The remaining 21% (6/29) reported pain that was the same as at baseline (before the procedure). The same study reported treatment failure (defined as conversion to surgery) in 3% (2/76) of patients at 12‑month follow‑up.
4.3 The randomised controlled trial of 28 patients treated by PIRFT or sham reported mean changes in pain VAS scores from baseline to 8 weeks of −0.61 in the PIRFT group and −1.14 in the sham group (VAS measured for 4 days and minimum and maximum scores recorded; difference between groups not significant). A randomised trial of 37 patients treated by PIRFT for 120 seconds (group A, n=19) or PIRFT for 360 seconds (group B, n=18) reported significant differences between mean pain scores before the procedure (± standard deviation; SD) and mean pain scores at 1 month in both groups, measured by VAS. The mean pain scores were 6.73±1.55 compared against 3.36±0.89 for group A and 6.27±1.31 compared against 3.33±0.97 for group B; p<0.05 for the difference compared against pre‑treatment scores. It reported no significant differences from pre‑treatment scores at 2-, 3- and 6‑month follow‑up in either group.
4.4 A non‑randomised trial of 31 patients treated by pulsed radiofrequency (n=15) or intradiscal electrothermal therapy (IDET, n=16) reported mean numerical rating scores for pain of 7.2 at baseline and 2.5 at 6‑month follow‑up in the pulsed radiofrequency group and 7.5 at baseline and 1.7 at 6 months in the IDET group (significant improvements within groups, p<0.01). No significant differences in mean numerical rating scale scores were observed between the groups at 6‑month follow‑up.
4.5 The randomised controlled trial of 28 patients treated by PIRFT or sham reported mean changes in function scores of −2.62 (measured using the Oswestry disability scale [ODS]; from 0 to 100 with lower scores indicating less disability) in the PIRFT group and −4.93 in the sham group at 8 weeks (p value for the difference between groups was not significant, and no significance test was reported for within group changes). The randomised trial of 37 patients comparing PIRFT for 120 seconds against PIRFT for 360 seconds reported significant differences between mean ODS scores before the treatment and at 1 month (±SD) in both groups (42±9% compared against 26±11% for 120 seconds and 42±10% compared against 24±12% for 360 seconds, p<0.05 for both groups). There were no significant differences at 6 months in either group. The non‑randomised trial of 31 patients treated by pulsed radiofrequency or IDET reported Roland Morris disability questionnaire scores (RMDQS; from 0 to 18, with lower scores indicating less disability). In the pulsed radiofrequency group, the reported RMDQS was 10.8 at baseline and 2.3 at 6 months after the procedure. In the IDET group the reported RMDQS was 10.4 at baseline and 2.8 at 6 months (significant improvements within both groups, p<0.01). There were no significant differences in RMDQS between groups at 6‑month follow‑up (p>0.05).
4.6 A case series of 8 patients treated by pulsed radiofrequency reported that all patients had stopped their regular pain medication after the procedure (no further details provided).
4.7 The specialist advisers listed key efficacy outcomes as reduction of back and leg pain, global improvement, reduction in disability, and work and domestic productivity.