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Table 1 Characteristics about efficacy and safety of included studies

From: Efficacy and safety of pulsed radiofrequency as a method of dorsal root ganglia stimulation for treatment of non-neuropathic pain: a systematic review

Author and year/Study design (Cochrane handbook and study authors)Interventions prior to PRF treatmentNumber of participants (for each pain condition treated)Follow-upOutcome measuresResults: efficacy for pain intensityConclusion statement about efficacyResults: serious adverse eventsResults: any other safety dataConclusion statement about safety
Low back pain (LBP)
Holanda 2016 [14]
RCT / pilot study
No other interventionPRF treatment group n = 11;
lidocaine injection group n = 7;
laser irradiation treatment group n = 10
5 min and 1 month1. Lumbar pain intensity by VAS presented as percentage of relative difference
2. Chronic LBP relief by PRS
PRF group:
VAS relative difference at 5 min: 62.5%
VAS relative difference at 1 month: 20%
Lidocaine injection group: VAS relative difference at 5 min: 100%
VAS relative difference at 1 month: 62.5%
Laser treatment group:
VAS relative difference at 5 min: 100%
VAS relative difference at 1 month: 55%
Positive conclusiveNo SAEs occurredSome patients experienced only mild discomfort during procedureNot reported
Lee 2018 [15]
RCT / randomized, prospective, and comparative study
Diagnostic block + PRF group received diagnostic block with 1 ml of 2% bupivacaine and 1 ml of 2% triamcinolone.Diagnostic block + PRF group (n = 30);
PRF group (n = 30)
2 weeks, 1, 3 and 6 months1. Pain intensity by NRS
2. Functional disabilities by ODI
Diagnostic block + PRF group:
Baseline NRS: 8 (range 5–9);
NRS at 2 weeks: 2 (range 1–7);
NRS at 1 month: 2 (range 1–8);
NRS at 3 months: 3 (range 1–8);
NRS at 6 months: 4 (range 1–8).
PRF alone group:
Baseline NRS: 7.5 range (3–10);
NRS at 2 weeks: 2 (range 1–9);
NRS at 1 month: 2 (range 1–9);
NRS at 3 months: 3 (range 1–9);
NRS at 6 months: 4 (range 1–9).
P values comparison between groups:
NRS at 2 weeks: P = 0.302
NRS at 1 month: P = 0.690
NRS at 3 moths: P = 0.957
NRS at 6 months: P = 0.673
Positive inconclusiveNot reportedNot reportedNot reported
Yang 2010 [16]
RCS / in vivo clinical trial
No other interventionPaMNI system n = 16;
conventional fluoroscopy n = 13
1 month1. Pain intensity by VASPaMNI group:
Baseline VAS: 5.8 (±2.3);
VAS at 1 month: 4.1 (±2.1).
P = 0.005.
Fluoroscopy group:
Baseline VAS: 6.5 (±2.2);
VAS at 1 month: 5.3 (±2.8).
P = 0.067.
No statistical difference between groups at 1 month (P = 0.238).
Positive conclusiveNot reportedNot reportedNot reported
Hsu 2017 [17]
BA / retrospective study
No other intervention841 week after the treatment and at 3, 6, 9, 12 months and yearly postoperatively (for 3 years in total)1. Pain intensity by VAS
2. Functional disabilities by ODI
Analysis of VAS scores for pain indicated significant reductions of low back pain during the 3-year follow-up for patients with all 4 types of lumbar lordosis.Positive conclusiveNo SAEs occurredCerebral spinal fluid leaking from the cannulas of two patients while the needle was being directed toward the DRG. This leakage ceased immediately after adjusting the location of the needle tip.Specific adverse events mention, no overall conclusion about safety
Tsou 2010 [18]
BA / not stated
No other interventionGroup A (CLBP without lower-limb pain) n = 49;
Group B (CLBP with lower-limb pain) n = 78
From 1 week up to 3 years post-operatively1. Pain intensity by VAS
2. Adverse events
Group A, L2 treatment:
≥50% VAS improvement:
at 1 week: 25/49 (51.02%);
at 3 months: 27/49 (55.1%);
at 1 year 20/45 (44.44%).
Group B, L2 treatment:
≥50% VAS improvement:
at 1 week: 34/78 (43.59%);
at 3 months: 37/78 (47.44%);
at 1 year: 34/74 (45.95%).
Positive conclusiveNo SAEs occurredNo obvious complications were observedPositive conclusive
Postsurgical pain
Albayrak 2017 [19]
PCS / retrospective study of prospectively collected
data
In the PRF group participants received prognostic diagnostic block prior to involvement.PRF group (TENS + exercise + PRF) n = 22;
TENS group (TENS + exercise) n = 17
15 days and 1-month post treatment and following last control examination. The mean follow-up time was 253.8 ± 109 days; for TENS group: 217 ± 114 days and for PRF group: 282.2 ± 97 days1. Pain intensity by VAS
2. Degree of neuropathic pain reduction by DN4
3. Change in knee flexion by ROM
4. Functional status by WOMAC
5. Patient satisfaction
Success was defined as at least 50% reduction to the VAS (activity, rest, night)
PRF group activity:
baseline VAS: 6.6 (±1.5);
VAS at 15 days: 3 (±1.4);
VAS at 1 month: 3.9 (±2);
VAS at last control: 3.5 (±2.4).
PRF group rest:
baseline VAS: 4.3 (±1.7);
VAS at 15 days: 1.8 (±0.9);
VAS at 1 month: 2.6 (±1.5);
VAS at last control: 2 (±1.6).
PRF group night:
baseline VAS: 3.8 (±2.2);
VAS at 15 days: 1.5 (±1.1);
VAS at 1 month: 2.1 (±1.4);
VAS at last control: 1.7 (±1.4).
TENS group activity:
baseline VAS: 5.9 (±1.9);
VAS at 15 days: 3.8 (±2.2);
VAS at 1 month: 4.3 (±2.2);
VAS at last control: 4.4 (±2.1).
TENS group rest:
baseline VAS: 5 (±2.4);
VAS at 15 days: 2.6 (±2.4);
VAS at 1 month: 3.4 (±2.5);
VAS at last control: 2.8 (±2.1).
TENS group night:
baseline VAS: 4.3 (±2.6);
VAS at 15 days: 2.1 (±2.7);
VAS at 1 month: 2.7 (±2.6);
VAS at last control: 2.6 (±1).
Significant difference achieved in an improvement of at least 50% on the VAS scores at activity following the last control examination between the two groups (P = 0.006), but not on the VAS scores at rest and night (P > 0.05).
Positive conclusiveNo SAEs occurredNo complications were observedNot reported
Cohen 2006 [20]
RCS / retrospective data analysis
No other interventionPRF DRG group n = 13;
PRF ICN group n = 15;
MM group n = 21
6 weeks, 3 months1. Pain intensity by VAS
2. Answers to 2 questions evaluating patient satisfaction and functional improvement
Successful was defined as ≥50% pain reduction on VAS and affirmative answer to 2 questions
No separate VAS scores shown in manuscript, success was achieved as follows.:
PRF DRG group:
6 weeks: 61.5%
3 months: 53.8%
PRF ICN group:
6 weeks: 21.4%
3 months: 6.7%
MM group:
6 weeks: 27.3%
3 months: 19.9%
Effect did not reach statistical significance at 6 weeks (P = 0.12).
At 3 months, success rate for PRF DRG group was significantly greater than for those patients treated with PRF ICN (P = 0.01), and approached significance when compared with MM (P = 0.06).
Positive conclusiveSmall incidental pneumothorax was found during a routine scan of the lung fields after PRF DRG. This patient was not symptomatic and was treated conservatively with observation.No other complications occurredNot reported
Fam 2018 [21]
BA / single arm intervention study
Steroid injections with 1 ml of bupivacaine 0.25% and 1 ml of dexamethasone 4 mg in a total volume of 2 ml immediately after PRF procedure.n = 1001 week, 1, 3 and 6 months1. Pain intensity by VAS
2. Quality of life by QOLS
3. Change in use of pain medication
4. Adverse effects
5. Patient satisfaction
Baseline VAS: 7.48 ± 1.46 (median: 8);
VAS at 1 week: 5.01 ± 2.61 (median: 5) (P = 0.032344);
VAS at 1 month: 3.26 ± 2.37 (median: 3) (P < 0.0001);
VAS at 3 months: 4.44 ± 2.8 (median: 4) (P = 0.00139);
VAS at 6 months: 4.7 ± 2.88 (median: 4) (P = 0.0057).
Positive inconclusiveNo SAEs occurredPain at the needling site, fever of unknown etiology at the night of intervention, mild to moderate elevation of glucose level in portion of diabetic participantsPositive inconclusive
Pain associated with herpes zoster
Kim 2017 [6]
RCS / retrospective cohort study
No other interventionPRF group n = 20;
continuous epidural group (ropivacaine) n = 22
1, 3 and 6 months1. Pain intensity by NRS
2. Dose of anticonvulsants and analgesics
PRF group:
baseline NRS: 6.30 ± 0.98
Continuous epidural group:
baseline NRS: 6.73 ± 0.88
NRS values were significantly lower in PRF group from 1  to 3 months and 6 months after the procedure (P = 0.029) than those in continuous epidural group.
Positive conclusiveNo SAEs occurred1 patient complained of pain at the procedure site, and it improved within few daysNot reported
Cervicogenic headache
van Zundert 2003 [22]
BA / clinical audit
Diagnostic block prior to involvement.
Participants with > 50% pain relief received PRF.
n = 142 months and 6 months after the last patient were included. Mean follow-up was 19.4 months (±8.9 months), maximum 2.5 years.1.Satisfactory pain relief (GPE: defined as a score of 6 or 7 points on the Likert scale; at least 50% pain relief
2. Duration of the effect
3. Other treatments
4. Change in use of pain medication
Data about pain relief (GPE):
9/14 patients (64%) reported successful pain reduction (6 or 7 points on the GPE Likert scale).
Positive conclusiveNo SAEs occurredNo other complications observedPositive conclusive
Zhang 2011 [23]
CR/CR
Diagnostic blocks with 1.5% lidocaine.
Positive response was considered as 90% pain relief lasting for 30 min.
n = 26 months1. Pain intensity by NRSPatient 1:
Baseline NRS: 5;
NRS at 6 months: 0.
Patient 2:
Baseline NRS: 4;
NRS at 6 months: 0.
Positive inconclusiveNo significant complications occurredNo significant complications occurredNot reported
Complex regional pain syndrome
Albayrak 2016 [24]
CR / CS
No other interventionn = 21 and 3 days after PRF, 2 and 5 or 10 months (different last follow-up time point for 2 patients)1. Pain intensity by VAS
2. ROM degree
Patient 1:
Baseline VAS during movement: 80;
VAS at 3 days: 30;
VAS at 2 and 10 months: 20.
Patient 2:
Baseline VAS during movement: 100;
VAS at 3 days: 30;
VAS at 2 months: 20;
VAS at 5 months: 10.
Positive inconclusiveNo SAEs occurredNo complications were observedNot reported
Apiliogullari 2015 [25]
CR / CR
No other interventionn = 11 day after treatment (2 weeks after first PRF the treatment was repeated), 6 months1. Pain intensity by VASBaseline VAS: 100;
VAS at 1 day (PRF on L5): 50;
VAS at 2 weeks (after repeated PRF on L4): 10.
The patient had symptoms relief for over 6 months.
Positive inconclusiveNo SAEs occurredNo significant complications occurredNot reported
Intractable vertebral metastatic pain
Arai 2015 [26]
CS / CR
No other interventionn = 150, 1, 7, 21, 28, 35 and 42 days1. Pain intensity by NRS at rest and while movingNRS at rest:
baseline NRS: from 1 to 4 (median 3);
NRS at day 1: median 2;
NRS at day 7: median 1;
NRS at day 21: median 1.
Significant decrease in 3 weeks (P < 0.0001).
NRS while moving:
baseline NRS from 5 to 10 (median 8);
NRS at day 1: median 4;
NRS at day 7: median 4;
NRS at day 21: median 3.
Significant decrease in 3 weeks (P < 0.0001).
Positive conclusiveNo SAEs occurredNo other complications occurredNot reported
Chronic scrotal and inguinal pain
Hofmeester 2013 [27]
CR / CR
Diagnostic block with 1 ml of levobupivacaine 0.25%n = 112 months1. Pain intensity by VASBaseline VAS scores: 7–8;
VAS initially after intervention: 4;
VAS at 12 months: 0–1.
Positive conclusiveNot reportedNot reportedNot reported
Occipital radiating pain in rheumatoid arthritis
Lee 2015 [28]
CR / CR
Diagnostic block with 0.3 ml of 0.75% levobupivacaine and 1 mg triamcinolonen = 16 months1. Pain intensity by VASBaseline VAS: 10;
VAS at 6 months: 0.
Positive conclusiveNot reportedNot reportedNot reported
Chronic migraine
Li 2018 [29]
CR / CR
Diagnostic block with 1 ml of 2% lidocainen = 11 year1. Pain intensity by VASBaseline VAS: 8;
VAS at 1 year: complete pain relief.
Positive inconclusiveNot reportedNot reportedNot reported
  1. Abbreviations: BA before and after, CR case report, CS case series, CLBP chronic low back pain, DRG dorsal root ganglion, GPE global perceived effect, ICN intercostal nerves, MM medical management, NRS numerical rating scale, ODI Oswestry disability index, PaMNI system patient-mount navigated intervention, PRF pulsed radiofrequency, PRS pain relief scale QOLS quality of life scale, RCS retrospective cohort study, ROM range of motion, TENS transcutaneous electrical nerve stimulation, SAEs serious adverse events, VAS visual analogue scale, WOMAC functional status by Western Ontario and McMaster universities osteoarthritis index