Efficacy of Radiofrequency Neurotomy in Chronic Low Back Pain: A Systematic Review and Meta-Analysis

Figures & data

Table 1 Sources of Risk of Bias and Cochrane Review Rating System

Bias Domain	Source of Bias		Possible Answers
Selection	(1) Was the method of randomization adequate?	A random (unpredictable) assignment sequence. Examples of adequate methods are coin toss (for studies with 2 groups), rolling a dice (for studies with 2 or more groups), drawing of balls of different colors, drawing of ballots with the study group labels from a dark bag, computer-generated random sequence, preordered sealed envelopes, sequentially ordered vials, telephone call to a central office, and preordered list of treatment assignments.	Yes/No/Unsure
		Examples of inadequate methods are: alternation, birth date, social insurance/security number, date in which they are invited to participate in the study, and hospital registration number.
Selection	(2) Was the treatment allocation concealed?	Assignment generated by an independent person not responsible for determining the eligibility of the patients. This person has no information about the persons included in the trial and has no influence on the assignment sequence or on the decision about eligibility of the patient.	Yes/No/Unsure
Performance	(3) Was the patient blinded to the intervention?	Index and control groups are indistinguishable for the patients or if the success of blinding was tested among the patients and it was successful.	Yes/No/Unsure
Performance	(4) Was the care provider blinded to the intervention?	Index and control groups are indistinguishable for the care providers or if the success of blinding was tested among the care providers and it was successful.	Yes/No/Unsure
Detection	(5) Was the outcome assessor blinded to the intervention?	Adequacy of blinding should be assessed for each primary outcome separately. This item should be scored “yes” if the success of blinding was tested among the outcome assessors and it was successful or:	Yes/No/Unsure
		● For patient-reported outcomes in which the patient is the outcome assessor (eg, pain, disability): the blinding procedure is adequate for outcome assessors if participant blinding is scored “yes”
		● For outcome criteria assessed during scheduled visit and that supposes a contact between participants and outcome assessors (eg, clinical examination): the blinding procedure is adequate if patients are blinded, and the treatment or adverse effects of the treatment cannot be noticed during clinical examination
		● For outcome criteria that do not suppose a contact with participants (eg, radiography, magnetic resonance imaging): the blinding procedure is adequate if the treatment or adverse effects of the treatment cannot be noticed when assessing the main outcome
		● For outcome criteria that are clinical or therapeutic events that will be determined by the interaction between patients and care providers (eg, cointerventions, hospitalization length, treatment failure), in which the care provider is the outcome assessor: the blinding procedure is adequate for outcome assessors if item “4” (caregivers) is scored “yes”
		● For outcome criteria that are assessed from data of the medical forms: the blinding procedure is adequate if the treatment or adverse effects of the treatment cannot be noticed on the extracted data
Attrition	(6) Was the drop-out rate described and acceptable?	The number of participants who were included in the study but did not complete the observation period or were not included in the analysis must be described and reasons given. If the percentage of withdrawals and drop-outs does not exceed 20% for short-term follow-up and 30% for long-term follow-up and does not lead to substantial bias a “yes” is scored (N.B. these percentages are arbitrary, not supported by literature).	Yes/No/Unsure
Attrition	(7) Were all randomized participants analyzed in the group to which they were allocated?	All randomized patients are reported/analyzed in the group they were allocated to by randomization for the most important moments of effect measurement (minus missing values) irrespective of noncompliance and cointerventions.	Yes/No/Unsure
Reporting	(8) Are reports of the study free of suggestion of selective outcome reporting?	All the results from all prespecified outcomes have been adequately reported in the published report of the trial. This information is either obtained by comparing the protocol and the report, or in the absence of the protocol, assessing that the published report includes enough information to make this judgment.	Yes/No/Unsure
Selection	(9) Were the groups similar at baseline regarding the most important prognostic indicators?	Groups have to be similar at baseline regarding demographic factors, duration and severity of complaints, percentage of patients with neurological symptoms, and value of main outcome measure(s).	Yes/No/Unsure
Performance	(10) Were cointerventions avoided or similar?	If there were no cointerventions or they were similar between the index and control groups.	Yes/No/Unsure
Performance	(11) Was the compliance acceptable in all groups?	The reviewer determines if the compliance with the interventions is acceptable, based on the reported intensity, duration, number and frequency of sessions for both the index intervention and control intervention(s). For example, physiotherapy treatment is usually administered for several sessions; therefore it is necessary to assess how many sessions each patient attended. For single-session interventions (eg, surgery), this item is irrelevant.	Yes/No/Unsure
Detection	(12) Was the timing of the outcome assessment similar in all groups?	Timing of outcome assessment should be identical for all intervention groups and for all primary outcome measures.	Yes/No/Unsure
Other	(13) Are other sources of potential bias unlikely?	Other types of biases. For example:	Yes/No/Unsure
		● When the outcome measures were not valid. There should be evidence from a previous or present scientific study that the primary outcome can be considered valid in the context of the present. ● Industry-sponsored trials. The conflict of interest (COI) statement should explicitly state that the researchers have had full possession of the trial process from planning to reporting without funders with potential COI having any possibility to interfere in the process. If, for example, the statistical analyses have been done by a funder with a potential COI, usually “unsure” is scored.

Notes: Adapted and modified from: Furlan AD, Malmivaara A, Chou R, et al; Editorial Board of the Cochrane Back, Neck Group. 2015 Updated method guideline for systematic reviews in the Cochrane Back and Neck Group. Spine (Phila Pa 1976). 2015;40(21):1660–1673. With permission from the American Society of Interventional Pain Physicians.⁵³

Table 2 Item Checklist for Assessment of Randomized Controlled Trials of IPM Techniques Utilizing IPM – QRB

		Scoring
I.	TRIAL DESIGN AND GUIDANCE REPORTING
1.	CONSORT or SPIRIT
	Trial designed and reported without any guidance	0
	Trial designed and reported utilizing minimum criteria other than CONSORT or SPIRIT criteria or trial was conducted prior to 2005	1
	Trial implies it was based on CONSORT or SPIRIT without clear description with moderately significant criteria for randomized trials or the trial was conducted before 2005	2
	Explicit use of CONSORT or SPIRIT with identification of criteria or trial conducted with high level reporting and criteria or conducted before 2005	3
II.	DESIGN FACTORS
2.	Type and Design of Trial
	Poorly designed control group (quasi selection, convenient sampling)	0
	Proper active-control or sham procedure with injection of active agent	2
	Proper placebo control (no active solutions into active structures)	3
3.	Setting/Physician
	General setting with no specialty affiliation and general physician	0
	Specialty of anesthesia/PMR/neurology/radiology/ortho, etc.	1
	Interventional pain management with interventional pain management physician	2
4.	Imaging
	Blind procedures	0
	Ultrasound	1
	CT	2
	Fluoro	3
5.	Sample Size
	Less than 50 participants in the study without appropriate sample size determination	0
	Sample size calculation with less than 25 patients in each group	1
	Appropriate sample size calculation with at least 25 patients in each group	2
	Appropriate sample size calculation with 50 patients in each group	3
6.	Statistical Methodology
	None or inappropriate	0
	Appropriate	1
III.	PATIENT FACTORS
7.	Inclusiveness of Population
7a.	For epidural procedures:
	Poorly identified mixed population	0
	Clearly identified mixed population	1
	Disorders specific trials (ie, well-defined spinal stenosis and disc herniation, disorder specific, disc herniation or spinal stenosis or post surgery syndrome)	2
7b.	For facet or sacroiliac joint interventions:
	No diagnostic blocks	0
	Selection with single diagnostic blocks	1
	Selection with placebo or dual diagnostic blocks	2
8.	Duration of Pain
	<3 months	0
	3–6 months	1
	> 6 months	2
9.	Previous Treatments
	Conservative management including drug therapy, exercise therapy, physical therapy, etc.
	Were not utilized	0
	Were utilized sporadically in some patients	1
	Were utilized in all patients	2
10.	Duration of Follow-up with Appropriate Interventions
	Less than 3 months or 12 weeks for epidural or facet joint procedures, etc. and 6 months for intradiscal procedures and implantables	0
	3–6 months for epidural or facet joint procedures, etc., or 1 year for intradiscal procedures or implantables	1
	6–17 months for epidurals or facet joint procedures, etc., and 2 years or longer for discal procedures and implantables	2
	18 months or longer for epidurals and facet joint procedures, etc., or 5 years or longer for discal procedures and implantables	3
IV.	OUTCOMES
11.	Outcomes Assessment Criteria for Significant Improvement
	No descriptions of outcomes OR <20% change in pain rating or functional status	0
	Pain rating with a decrease of 2 or more points or more than 20% reduction OR functional status improvement of more than 20%	1
	Pain rating with decrease of ≥2 points AND ≥20% change or functional status improvement of ≥20%	2
	Pain rating with a decrease of 3 or more points or more than 50% reduction OR functional status improvement with a 50% or 40% reduction in disability score	2
	Significant improvement with pain and function ≥50% or 3 points and 40% reduction in disability scores	4
12.	Analysis of all Randomized Participants in the Groups
	Not performed	0
	Performed without intent-to-treat analysis without inclusion of all randomized participants	1
	All participants included with or without intent-to-treat analysis	2
13.	Description of Drop-Out Rate
	No description of dropouts, despite reporting of incomplete data or ≥20% withdrawal	0
	Less than 20% withdrawal in 1 year in any group	1
	Less than 30% withdrawal at 2 years in any group	2
14.	Similarity of Groups at Baseline for Important Prognostic Indicators
	Groups dissimilar with significant influence on outcomes with or without appropriate randomization and allocation	0
	Groups dissimilar without influence on outcomes despite appropriate randomization and allocation	1
	Groups similar with appropriate randomization and allocation	2
15.	Role of Co-Interventions
	Co-interventions were provided but were not similar in the majority of participants	0
	No co-interventions or similar co-interventions were provided in the majority of the participants	1
V.	Randomization
16.	Method of Randomization
	Quasi randomized or poorly randomized or not described	0
	Adequate randomization (coin toss, drawing of balls of different colors, drawing of ballots)	1
	High quality randomization (Computer generated random sequence, pre-ordered sealed envelopes, sequentially ordered vials, telephone call, pre-ordered list of treatment assignments, etc)	2
VI.	ALLOCATION CONCEALMENT
17.	Concealed Treatment Allocation
	Poor concealment of allocation (open enrollment) or inadequate description of concealment	0
	Concealment of allocation with borderline or good description of the process with probability of failure of concealment	1
	High-quality concealment with strict controls (independent assignment without influence on the assignment sequence)	2
VII.	BLINDING
18.	Patient Blinding
	Patients not blinded	0
	Patients blinded adequately	1
19.	Care Provider Blinding
	Care provider not blinded	0
	Care provider blinded adequately	1
20.	Outcome Assessor Blinding
	Outcome assessor not blinded or was able to identify the groups	0
	Performed by a blinded independent assessor with inability to identify the assignment-based provider intervention (ie, subcutaneous injection, intramuscular distant injection, difference in preparation or equipment use, numbness and weakness, etc.)	1
VIII.	CONFLICTS OF INTEREST
21.	Funding and Sponsorship
	Trial included industry employees	−3
	Industry employees involved; high levels of funding with remunerations by industry or an organization funded with conflicts	−3
	Industry or organizational funding with reimbursement of expenses with some involvement	0
	Industry or organization funding of expenses without involvement	1
	Funding by internal resources only with supporting entity unrelated to industry	2
	Governmental funding without conflict such as NIH, NHS, AHRQ	3
22.	Conflicts of Interest
	None disclosed with potential implied conflict	0
	Marginally disclosed with potential conflict	1
	Well disclosed with minor conflicts	2
	Well disclosed with no conflicts	3
	Hidden conflicts with poor disclosure	–1
	Misleading disclosure with conflicts	–2
	Major impact related to conflicts	–3
TOTAL		48

Notes: Source: Manchikanti L, Hirsch JA, Cohen SP, et al. Assessment of methodologic quality of randomized trials of interventional techniques: Development of an interventional pain management specific instrument. Pain Physician. 2014;17(3):E263-E290.⁵⁴

Table 3 Qualitative Modified Approach to Grading of Evidence of Therapeutic Effectiveness Studies

Level I	Strong	Evidence obtained from multiple relevant high-quality randomized controlled trials
Level II	Moderate	Evidence obtained from at least one relevant high-quality randomized controlled trial or multiple relevant moderate or low-quality randomized controlled trials
Level III	Fair	Evidence obtained from at least one relevant moderate or low-quality randomized trial or Evidence obtained from at least one relevant high-quality non-randomized trial or observational study with multiple moderate or low-quality observational studies
Level IV	Limited	Evidence obtained from multiple moderate or low-quality relevant observational studies
Level V	Consensus based	Opinion or consensus of large group of clinicians and/or scientists

Notes: Modified from: Manchikanti L, Falco FJE, Benyamin RM, Kaye AD, Boswell MV, Hirsch JA. A modified approach to grading of evidence. Pain Physician. 2014;17(3):E319-E325.⁵⁵.

Figure 1 Flow diagram illustrating the results of literature search conducted to evaluate lumbar radiofrequency thermoneurolysis.

Table 4 Methodological Quality Assessment of Randomized Trials of Lumbar Facet Joint Radiofrequency Thermoneurolysis Utilizing Cochrane Review Criteria⁵³

	Juch et al^Citation61	Nath et al^Citation65	Tekin et al^Citation67	van Wijk et al^Citation68	van Kleef et al^Citation69	Çetin & Yektaş^Citation56	Lakemeier et al^Citation59
Randomization adequate	Y	Y	Y	Y	Y	Y	Y
Concealed treatment allocation	N	Y	Y	Y	Y	Y	Y
Patient blinded	N	Y	Y	Y	Y	Y	Y
Care provider blinded	N	Y	Y	Y	Y	N	N
Outcome assessor blinded	N	Y	Y	Y	Y	Y	N
Drop-out rate described	N	Y	Y	Y	Y	Y	Y
All randomized participants analyzed in the group	N	Y	Y	Y	Y	Y	Y
Reports of the study free of suggestion of selective outcome reporting	N	Y	Y	Y	Y	Y	Y
Groups similar at baseline regarding most important prognostic indicators	Y	Y	Y	Y	Y	Y	Y
Co-intervention avoided or similar in all groups	Y	Y	Y	Y	Y	Y	Y
Compliance acceptable in all groups	Y	Y	Y	Y	Y	Y	N
Time of outcome assessment in all groups similar	Y	Y	Y	Y	Y	Y	Y
Are other sources of potential bias not likely	Y	Y	U	Y	Y	Y	U
SCORE	6/13	13/13	12/13	13/13	13/13	12/13	9/13
	Dobrogowski et al^Citation60	McCormick et al^Citation62	Moon et al^Citation63	Moussa & Khedr^Citation64	Song et al^Citation66
Randomization adequate	Y	Y	Y	Y	U
Concealed treatment allocation	U	Y	Y	Y	U
Patient blinded	Y	Y	Y	Y	N
Care provider blinded	Y	N	Y	N	N
Outcome assessor blinded	U	Y	Y	Y	Y
Drop-out rate described	Y	Y	Y	Y	N
All randomized participants analyzed in the group	Y	Y	N	U	U
Reports of the study free of suggestion of selective outcome reporting	Y	Y	Y	Y	Y
Groups similar at baseline regarding most important prognostic indicators	Y	Y	Y	Y	Y
Co-intervention avoided or similar in all groups	Y	Y	Y	Y	N
Compliance acceptable in all groups	Y	Y	N	U	Y
Time of outcome assessment in all groups similar	Y	Y	N	Y	Y
Are other sources of potential bias not likely	U	U	U	Y	Y
SCORE	10/13	11/13	9/13	10/13	6/13

Abbreviations: Y, yes; N, no; U, unclear.

Table 5 Methodologic Quality Assessment of Randomized Trials of Lumbar Facet Joint Radiofrequency Thermoneurolysis Utilizing IPM – QRB Criteria⁵⁴

		Juch et al^Citation61	Nath et al^Citation65	Tekin et al^Citation67	van Wijk et al^Citation68	van Kleef et al^Citation69	Çetin & Yektaş^Citation56	Lakemeier et al^Citation59	Dobrogowski et al^Citation60
I.	TRIAL DESIGN AND GUIDANCE REPORTING
1.	CONSORT or SPIRIT	2	3	2	2	2	2	2	2
II.	DESIGN FACTORS
2.	Type and Design of Trial	2	2	2	2	2	2	2	3
3.	Setting/Physician	2	2	2	2	1	2	1	2
4.	Imaging	3	3	3	3	3	3	3	3
5.	Sample Size	2	3	2	2	2	2	2	1
6.	Statistical Methodology	1	1	1	1	1	1	1	1
III.	PATIENT FACTORS
7.	Inclusiveness of Population	2	1	2	2	1	2	1	1
8.	Duration of Pain	2	0	2	2	2	2	2	2
9.	Previous Treatments	1	0	1	2	2	2	2	2
10.	Duration of Follow-up with Appropriate Interventions	1	0	1	1	2	3	2	2
IV.	OUTCOMES
11.	Outcomes Assessment Criteria for Significant Improvement	1	0	1	2	2	2	2	2
12.	Analysis of all Randomized Participants in the Groups	0	2	0	0	2	2	2	1
13.	Description of Drop-Out Rate	0	2	0	2	2	2	2	1
14.	Similarity of Groups at Baseline for Important Prognostic Indicators	2	2	2	2	2	2	2	2
15.	Role of Co-Interventions	1	1	1	1	1	1	1	1
V.	RANDOMIZATION
16.	Method of Randomization	2	2	2	2	2	2	2	2
VI.	ALLOCATION CONCEALMENT
17.	Concealed Treatment Allocation	0	0	0	2	2	2	2	2
VII.	BLINDING
18.	Patient Blinding	0	0	0	1	1	1	1	1
19.	Care Provider Blinding	0	0	0	1	0	1	0	0
20.	Outcome Assessor Blinding	0	0	0	1	0	1	0	1
VIII.	CONFLICTS OF INTEREST
21.	Funding and Sponsorship	2	2	2	2	2	2	2	2
22.	Conflicts of Interest	0	2	0	3	3	0	3	3
TOTAL		26	28	26	38	37	39	37	37
					McCormick et al^Citation62		Moon et al^Citation63	Moussa & Khedr^Citation64	Song et al^Citation66
I.	TRIAL DESIGN AND GUIDANCE REPORTING
1.	CONSORT or SPIRIT				2		2	2	2
II.	DESIGN FACTORS
2.	Type and Design of Trial				3		2	3	2
3.	Setting/Physician				2		2	1	1
4.	Imaging				3		3	3	3
5.	Sample Size				1		2	2	0
6.	Statistical Methodology				1		1	1	1
III.	PATIENT FACTORS
7.	Inclusiveness of Population				1		2	2	2
8.	Duration of Pain				2		2	2	1
9.	Previous Treatments				2		2	2	2
10.	Duration of Follow-up with Appropriate Interventions				2		1	3	3
IV.	OUTCOMES
11.	Outcomes Assessment Criteria for Significant Improvement				2		2	2	2
12.	Analysis of all Randomized Participants in the Groups				1		0	1	0
13.	Description of Drop Out Rate				1		2	2	0
14.	Similarity of Groups at Baseline for Important Prognostic Indicators				2		2	2	2
15.	Role of Co-Interventions				1		1	1	1
V.	RANDOMIZATION
16.	Method of Randomization				2		2	2	0
VI.	ALLOCATION CONCEALMENT
17.	Concealed Treatment Allocation				2		2	2	0
VII.	BLINDING
18.	Patient Blinding				1		1	1	0
19.	Care Provider Blinding				0		1	0	0
20.	Outcome Assessor Blinding				1		1	1	1
VIII.	CONFLICTS OF INTEREST
21.	Funding and Sponsorship				2		2	3	3
22.	Conflicts of Interest				3		3	3	3
TOTAL					37		41	41	29

Table 6 Study Characteristics of Randomized Controlled Trials Assessing Lumbar Radiofrequency Neurotomy

Study Study Characteristic Methodological Quality Scoring	Number of Patients & Selection Criteria	Control	Interventions	Outcome Measures	Time of Measurement	Results	Strengths	Weaknesses	Conclusions
Juch et al,^Citation61 2017 MINT randomized, non-blinded, pragmatic clinical trial Quality Scores: Cochrane = 6/13 IPM-QRB = 26/48	A total of 251 patients were randomized into facet trial with 126 patients in the control group receiving exercise program as randomized. 125 patients were randomized to intervention group.	Patients randomized to control group received exercise program as randomized.	Patients in the intervention group, radiofrequency ablation after testing positive with at least 50% relief with a single block of facet joint nerves with pain reduction within 30 to 90 minutes after the block. Radiofrequency neurotomy was performed with a conventional radiofrequency ablation procedure with a 22 gauge electrode. Co-interventions except standardized exercise program were not allowed for 3 months. Over-the-counter analgesics were allowed.	NRS, global perceived recovery, Oswestry Disability Index, EuroQol 5D Health Questionnaire, Rand-36, West Haven-Yale Multidimensional Pain Inventory	3, 6, 9, 12 months	There was no significant difference between radiofrequency ablation group compared to exercise program group in the control.	A large randomized clinical trial	There are numerous weaknesses in this trial. Inappropriate selection criteria with 50% relief for a few hours which is not recommended by any guidelines. Not a blinded procedure. The electrode was too thin with exposed tip may or may not be over the nerve utilizing a perpendicular placement of the electrode. Outcome measures were inappropriate. This study received extensive correspondence and negative comments all over for its defective design and performance.	A poorly designed and performed trial showing negative results.
Nath et al,^Citation65 2008 Randomized, double-blind, sham control trial Quality Scores: Cochrane = 13/13 IPM-QRB = 28/48	40 patients with chronic low back pain for at least 2 years with 80% relief of low back pain after controlled medial branch blocks. The patients were randomized into an active and a control group.	Sham control with placement of the needles with injection of local anesthetic without radiofrequency neurotomy.	The 20 patients in the active group received conventional lumbar facet joint radiofrequency neurolysis at 85°C for 60 seconds. The 20 patients in the control group received sham treatment without radiofrequency neurolysis of the lumbar facet joints.	NRS, global functional improvement, reduced opioid intake, employment status.	6 months	Significant reduction not only in back, and leg pain; functional improvement; opioid reduction; and employment status in the active group compared to the control group.	Randomized, double-blind trial after the diagnosis of facet joint pain with triple diagnostic blocks	Short-term follow-up with small number of patients	Efficacy of radiofrequency neurotomy was shown compared to local anesthetic injection and sham lesioning.
Tekin et al,^Citation67 2007 Randomized, active and sham, double-blind controlled trial Quality Scores: Cochrane = 12/13 IPM-QRB = 26/48	60 patients with chronic low back pain randomized into 3 groups with 20 patients in each group. Single diagnostic block of facet joint nerves with 0.3 mL of lidocaine 2% with 50% or greater relief.	Sham control with local anesthetic injection	Either pulsed radiofrequency (42°C for 4 minutes) or conventional radiofrequency neurotomy (80°C for 90 seconds) in 20 patients in each group.	VAS and ODI	3, 6, and 12 months	VAS and ODI scores decreased in all groups from 3 procedural levels. Decrease in pain scores was maintained in the conventional radiofrequency group at 6 months and one year. However, in pulsed radiofrequency group, the improvement was significant only at 6 months, but not one year.	Randomized, double-blind, controlled trial comparing control, pulsed radiofrequency, and conventional radiofrequency neurotomy. Authors also utilized a parallel needle placement approach	Small sample size with a single block and 50% relief as inclusion criteria. Authors did not report significant improvement percentages.	Efficacy with conventional radiofrequency neurotomy up to one year, whereas efficacy with local anesthetic block with sham control radiofrequency neurotomy and pulsed radiofrequency neurotomy at 6 months only.
van Wijk et al,^Citation68 2005 Randomized, double-blind, sham control trial Quality Scores: Cochrane = 13/13 IPM-QRB = 38/48	81 patients with chronic low back pain were evaluated with radiofrequency neurotomy with 41 patients in the control group with at least 50% relief for 30 minutes with a single block with intraarticular injection of 0.5 mL lidocaine 2%.	Sham lesion procedure after local anesthetic injection	40 patients received conventional radiofrequency lesioning at 80°C for 60 seconds and 41 patients received sham lesioning.	Pain relief, physical activities, analgesic intake, GPE, Short-form-36, quality of life measures	3 months	GPE improved after radiofrequency facet joint denervation. The Visual Analog Scale in both groups improved. The combined outcome measures showed no difference between radiofrequency facet joint denervation (27.5% vs 29.3% success rate).	Double-blind, sham control, randomized trial	Poor selection with a single diagnostic block of 50% pain reduction even though 17.5% of the patients were tested positive. Further, authors described that the needle was positioned parallel; however, the radiographic figures illustrate the needle was being positioned perpendicularly rather than parallel to the nerve.	Lack of efficacy with methodologic deficiencies and a short-term follow-up.
Van Kleef et al,^Citation69 1999 Randomized, double-blind, sham control trial Quality Scores: Cochrane = 13/13 IPM-QRB = 37/48	31 patients with a history of at least one year of chronic low back pain randomly assigned to one of 2 treatment groups. Single diagnostic block with 50% relief.	Sham control of radiofrequency after local anesthetic injection in 16 patients	The 15 patients in the conventional radiofrequency treatment group received an 80° C radiofrequency lesion for 60 seconds.	VAS, pain scores, GPE, ODI	3, 6, and 12 months	After 3, 6, and 12 months, the number of successes in the lesion and sham groups was 9 of 15 (60%) and 4 of 16 (25%), 7 of 15 (47%) and 3 of 16 (19%), and 7 of 15 (47%) and 2 of 16 (13%) respectively. There was a statistically significant difference.	Double-blind, randomized, sham controlled trial	A single block with a small sample with inclusion criteria of 50% pain relief to enter the study. The study has been criticized that electrodes were placed at an angle to the target nerve, instead of parallel.	Efficacy shown in a small sample with a single diagnostic block
Çetin & Yektaş,^Citation56 2018 Randomized, double-blind, active-controlled trial Quality Scores: Cochrane = _12/13 IPM-QRB = 39/48	118 patients were randomized to Group 1 to receive pulsed radiofrequency and Group 2 with 45 patients receiving conventional radiofrequency.	Pulsed radiofrequency was performed at 42° for 30 minutes. Bupivacaine was injected prior to the procedure and following the procedure, 2 mg of methylprednisolone was injected through RF needle at each level in both groups.	Conventional radiofrequency ablation was performed at 80° for 90 seconds. Bupivacaine was injected prior to the procedure and following the procedure, 2 mg of methylprednisolone was injected through RF needle at each level in both groups.	VAS, Odom criteria	1, 3, 6 months, 1 year, 2 years	Conventional radiofrequency ablation provided significantly better relief at 6 months, one year, and 2 years.	Randomized, double-blind control trial	Active control trials	This trial shows excellent outcomes with conventional radiofrequency neurotomy over a period of 2 years.
Lakemeier et al,^Citation59 2013 Randomized, double-blind, active controlled trial Quality Scores: Cochrane = 9/13 IPM-QRB = 37/48	56 patients were randomized into 2 groups with 29 patients receiving intraarticular steroid injections and 27 patients receiving radiofrequency denervation after the diagnosis was made with intraarticular injection of local anesthetic with a single block with pain reduction of at least 50%.	Intraarticular injection of local anesthetic and steroid	Radiofrequency neurotomy for 90 seconds at 80°C	Roland-Morris questionnaire, VAS, ODI, analgesic intake	6 months	Pain relief and functional improvement were observed in both groups. There were no significant differences between the 2 groups for pain relief and functional status improvement.	Lack of placebo group. Relatively short-term follow-up.	Randomized, double-blind trial with single diagnostic block with intraarticular injection	Both groups showed improvement. Effectiveness at 6 months in both groups with intraarticular injection or radiofrequency neurotomy.
Dobrogowski et al,^Citation60 2005 Randomized, active control trial Quality Scores: Cochrane = 10/13 IPM-QRB = 37/48	45 consecutive patients with chronic low back pain judged to be positive with significant relief with 2 controlled diagnostic blocks	Injection of saline in patients after conventional radiofrequency (85° for 60 seconds) neurotomy to evaluate postoperative pain	Conventional radiofrequency neurotomy at 85°C for 60 seconds, followed by injection of either methylprednisolone or pentoxifylline	VAS, minimum of 50% reduction of pain intensity, patient satisfaction score	One, 3, 6, and 12 months	≥ 50% reduction of pain intensity was observed in 66% of the patients 12 months later. There was no difference in the long-term outcomes.	Randomized, active control trial	Very small study with highly defined inclusion criteria evaluating effectiveness of radiofrequency neurotomy and postoperative pain.	Radiofrequency neurotomy effective with or without steroid injection after neurolysis.
McCormick et al,^Citation62 2019 Randomized, single blinded, controlled trial. Quality Scores: Cochrane = 11/13 IPM-QRB = 37 /48	43 patients were randomized to two groups, 21 received cooled radiofrequency ablation while 22 received traditional radiofrequency ablation of medial branch nerve. Patients who had at least 75% pain relief on a diagnostic block were included in study.	Received traditional percutaneous radiofrequency ablation of medial branch nerve.	Received cooled percutaneous radiofrequency ablation of medial branch nerve.	Primary outcome: ≥50% NRS reduction at 6 months. Secondary outcomes: NRS, ODI and patient global impression of change.	6 months	A ≥50% decrease in NRS was observed in 52% (95% CI 31% to 74%) and 44% (95% CI 22% to 69%) in the cooled RFA and traditional RFA respectively with no significant difference between the groups (p=0.75).	Randomized, single blinded.	Relatively small sample size, up to 7% participants outcomes were not reported. Followed only for 6 months. Not a double blinded study.	Study showed both cooled radiofrequency ablation and traditional radiofrequency ablation had over 50% success rates in reducing pain and improving function at 6 months. However, there was no significant difference between the groups.
Moon et al,^Citation63 2013 Randomized, active control, comparative analysis Quality Scores: Cochrane = 9/13 IPM-QRB = 41/48	82 patients were included with low back pain with 41 patients in each group either with a parallel placement of the needle or perpendicular placement of the needle. Concordant pain relief of >50% after a comparative local anesthetic block.	An active control trial with needle placement with perpendicular approach.	41 patients in each group were treated with radiofrequency (80°C for 90 seconds) after appropriate diagnosis of facet joint pain with dual diagnostic blocks with 50% relief as the criterion standard. The needle was positioned either utilizing a discal or perpendicular approach or utilizing a tunnel vision approach with parallel placement of the needle.	NRS, ODI	One month and 6 months	Patients in both groups showed a statistically significant reduction in NRS and Oswestry Disability Index scores from baseline to that of the scores at one and 6 months (all P < 0.0001, Bonferroni corrected).	Randomized, double-blind, controlled trial. The major strength is that authors have proven that parallel approach may not be the best as has been described. Diagnosis of facet joint pain by dual blocks.	Active controlled trial without placebo group. Short-term follow-up.	Positive results in an active controlled trial, in a relatively short-term follow-up of 6 months, with positioning of the needle either with distal approach (perpendicular placement or tunnel vision) with parallel placement of the needle with some superiority with perpendicular approach. This trial abates any criticism of needle positioning one way or the other and the traditional needle positioning appears to be superior to parallel needle placement.
Moussa and Khedr,^Citation64 2016 Randomized, double-blind, active-controlled trial Quality Scores: Cochrane = 10/13 IPM-QRB = 41/48	120 patients were randomized to three groups of 40 each. First group received percutaneous radiofrequency coagulation of the facet joint capsule, second group underwent percutaneous denervation of the medical dorsal branch and the third wash sham group. Patients with chronic low back pain for over one year duration despite of at least three months of conservative management and who achieved near complete pain reduction after two diagnostic blocks.	Sham lesion procedure after local anesthetic injection	One group received percutaneous radiofrequency coagulation of facet joint capsule and the second group underwent percutaneous denervation of the medial dorsal branch.	Several outcome measures were measured VAS, ODI, and GPE. However the primary outcome was determined by a predefined multidimensional COM at one year follow-up.	3, 6, 12, 24, and 36 months.	Success measured by COM at 1 year in the radiofrequency coagulation of joint capsule, denervation of medial dorsal branch and sham groups were 67.5%, 57.5% and 10% respective which was statistically significant (p=0.038).	Randomized double blinded. All the interventional procedures were done by one neurosurgeon reducing potential operator-dependent confounding. patients diagnosed with facet joint pain by dual blocks.	Relatively small sample size, average. 8, 13 and 20% patients lost to follow up at 1, 2 and 3 years respectively.	Study showed that both radiofrequency coagulation of facet joint capsule and medial branch nerve significantly improved pain in chronic low back pain patients at one year compared to the sham group. However, these benefits were seen at 2 and 3 years follow-up for group in which the facet joint capsule was targeted but diminished in the group in which medial branch nerve was targeted.
Song et al,^Citation66 2019 Randomized, single-blind (investigator), active-controlled trial Quality Scores: Cochrane = 6/13 IPM-QRB = 29/48	40 patients were randomized to two groups of 20 each. One group received Radiofrequency neurotomy while the other group underwent endoscopic neurotomy. Patients who had at least 3 months of chronic low back pain and showed at least 80% pain relief following a single diagnostic block.	The control group underwent endoscopic neurotomy of lumbar medial branch nerve.	The intervention group underwent fluoroscopy assisted radiofrequency neurotomy of lumbar medial branch nerve.	VAS and ODI scores were measured.	3weeks, 6 months, 1 and 2 years.	Radiofrequency group showed significant effectiveness at 3 weeks, 6 months, and 1 year but not significantly effective at 2 years. Endoscopy group showed significantly effective at even at 2 years but the efficacy declined. There was no significant difference between the groups at 3 weeks after the procedure however, at 6 months and longer the endoscopy group showed significantly better outcomes.	Randomized, investigator blinded study.	Very small sample size, single blinded (investigator only), single center, and patients medication and physiotherapy were not taken into account. Single diagnostic block was used for diagnosis.	Both radiofrequency neurotomy and endoscopic neurotomy of the medial branch nerve were effective but endoscopic neurotomy has better and longer lasting outcomes.

Abbreviations: VAS, Visual Analog Scale; ODI, Oswestry Disability Index; RF, radiofrequency; NRS, Numeric rating scale; GPE, global perceived effect; COM, combined outcome measure; IPM-QRB, interventional pain management techniques- quality appraisal of reliability and risk of bias assessment.

Table 7 Effectiveness of Lumbar Radiofrequency in Facet Joint Pain

Study Study Characteristic Methodological Quality Scoring	Patients	Interventions	Pain Relief and Function			Results			Comments
			3 Mos.	6 Mos.	12 Mos.	Short-Term ≤ 6 Mos.	Long-Term
							> 6 Mos.	≥ 1 Year
Juch et al,^Citation61 2017 MINT randomized, non-blinded, pragmatic clinical trial Quality Scores: Cochrane = 6/13 IPM-QRB = 26/48	A total of 251 patients were randomized into facet trial with 126 patients in the control group receiving exercise program as randomized. 125 patients were randomized to intervention group.	Patients in the intervention group, radiofrequency ablation after testing positive with at least 50% relief with a single block of facet joint nerves with pain reduction within 30 to 90 minutes after the block. Radiofrequency neurotomy was performed with a conventional radiofrequency ablation procedure with a 22 gauge electrode.	NSD	NSD	NSD	N	N	N	Lack of effectiveness
Nath et al,^Citation65 2008 RA, DB, Sham control Quality Scores: Cochrane = 13/13 IPM-QRB = 28/48	40	Radiofrequency = 20 Sham = 20	NA	Significant proportion of patients in interventional group	NA	P for radiofrequency N for sham or active	P for radiofrequency N for sham or active	NA	Effective for short-term and long-term
Tekin et al,^Citation67 2007 RA, AC and sham, DB Quality Scores: Cochrane = 12/13 IPM-QRB = 26/48	60	CRF = 20 PRF = 20 Control = 20	NA	SI with CRF	SI with CRF	NA	P for radiofrequency N for sham	P for radiofrequency N for sham	Effective for long-term improvement
van Wijk et al,^Citation68 2005 RA, DB, Sham control Quality Scores: Cochrane = 13/13 IPM-QRB = 38/48	81	Radiofrequency = 40 Sham = 41	27.5% vs 29.3%	27.5% vs 29.3%	27.5% vs 29.3%	N	N	N	Lack of effectiveness with short- and long-term
Dobrogowski et al,^Citation60 2005 RA, AC Quality Scores: Cochrane = 10/13 IPM-QRB = 37/48	45	CRF	NA	60%	NA	NA	P	NA	Short-term effectiveness
van Kleef et al,^Citation69 1999 RA, DB, sham control Quality Scores: Cochrane = 13/13 IPM-QRB = 37/48	31	Radiofrequency = 15 Sham = 16	60% vs 25%	47% vs 19%	47% vs 13%	P for radiofrequency N for sham or active	P for radiofrequency N for sham	P for radiofrequency N for sham	Effectiveness with short- and long-term
Moon et al,^Citation63 2013 Prospective, RA, comparative study Quality Scores: Cochrane = 9/13 IPM-QRB = 41/48	Total = 82 Tunnel vision approach group – 41 patients included and 34 patients analyzed.	Radiofrequency neurotomy distal approach	SI in both groups	SI in both groups	NA	P	P	NA	Short-term effectiveness
Lakemeier et al,^Citation59 2013 RA, DB Quality Scores: Cochrane = 9/13 IPM-QRB = 37/48	Total = 56 Steroid group = 29 patients Radiofrequency group = 27 patients	Intraarticular lumbar facet joint steroid injections compared to lumbar facet joint radiofrequency denervation	NA	SI in both groups	NA	P	P	NA	Short -term effectiveness
Çetin & Yektaş,^Citation56 2018 Randomized, double-blind, controlled trial Quality Scores: Cochrane = 12/13 IPM-QRB = 39/48	118 patients were randomized to Group 1 to receive pulsed radiofrequency and Group 2 with 45 patients receiving conventional radiofrequency.	Pulsed radiofrequency vs conventional radiofrequency	SI	SI	SI	P	P	P	Positive trial for CRF for short and long-term effectiveness
McCormick et al,^Citation62 2019 Randomized, single-blind, comparative study Quality score: Cochrane = 11/13 IPM-QRB = 37/48	43	MBN cooled RFA = 21 MBN traditional RFA = 22	NA	SI in both groups	NA	P	NA	NA	Both effective for short term. No significant difference between the groups
Moussa & Khedr,^Citation64 2016 Randomized, double blind, controlled trial, sham control Quality score: Cochrane = 10/13 IPM-QRB = 41/48	120	Radio frequency coagulation of facet joint capsule = 40 Radio frequency denervation of medial dorsal branch =40 Sham = 40	SI in all three groups	SI in two groups except sham group	SI in two groups except sham group	P	P	P	Both intervention groups effective for short term and long term
Song et al,^Citation66 2019 Randomized, unblinded, comparative study Quality score: Cochrane = 6/13 IPM-QRB = 29/48	40	Radiofrequency neurotomy = 20 Endoscopic neurotomy = 20 of lumbar medial branch	SI in both the groups	SI in both the groups	SI in both the groups	P	P	P	Both groups effective for up to one year. The radiofrequency group lost effectiveness at 2 years

Abbreviations: RA, randomized; DB, double-blind; AC, active control; ST, steroid; LA, local anesthetic; SAL, saline; SI, significant improvement; NSD, no significant difference; NE, not effective; CRFA, radiofrequency Ablation; P, positive; N, negative; NA, not applicable, MBN, medial branch nerve; IPM-QRB, interventional pain management techniques- quality appraisal of reliability and risk of bias assessment.

Figure 2 (A) Conventional dual-arm meta-analysis of pain relief of radiofrequency neurotomy vs sham control group at 6-month follow-up. (B) Conventional dual-arm meta-analysis of pain relief of radiofrequency neurotomy vs sham control group at 12-month follow-up.

Figure 3 (A) Conventional dual-arm meta-analysis of pain relief of radiofrequency neurotomy of active control trials at 6 -month follow-up. (B) Conventional dual-arm meta-analysis of pain relief of radiofrequency neurotomy of active control trials at 12-month follow-up.

Figure 4 (A) Conventional dual-arm meta-analysis of functional status (ODI) of radiofrequency neurotomy vs sham control group at 6-month follow-up. (B) Conventional dual-arm meta-analysis of functional status (ODI) of radiofrequency neurotomy vs sham control group at 12-month follow-up.

Figure 5 (A) Single arm meta-analysis of pain relief of radiofrequency neurotomy at baseline vs at 6-month follow-up of active-controlled trials. (B) Single arm meta-analysis of pain relief of radiofrequency neurotomy at baseline vs at 12-month follow-up of active control trials.

Figure 6 (A) Single-arm meta-analysis of functional status (ODI) of radiofrequency neurotomy at 6-month follow-up in sham control trials. (B) Single-arm meta-analysis of functional status (ODI) of radiofrequency neurotomy at 12 month follow-up in sham control trials.

Furlan AD, Malmivaara A, Chou R, et al; Editorial Board of the Cochrane Back, Neck Group. 2015 updated method guideline for systematic reviews in the Cochrane back and neck group. Spine (Phila Pa 1976). 2015;40(21):1660–1673. doi:10.1097/BRS.0000000000001061.

 PubMed Web of Science ®Google Scholar

Manchikanti L, Hirsch JA, Cohen SP, et al. Assessment of methodologic quality of randomized trials of interventional techniques: development of an interventional pain management specific instrument. Pain Physician. 2014;17(3):E263–E290. doi:10.36076/ppj.2014/17/E263

 PubMed Web of Science ®Google Scholar

Manchikanti L, Falco FJE, Benyamin RM, Kaye AD, Boswell MV, Hirsch JA. A modified approach to grading of evidence. Pain Physician. 2014;17(3):E319–E325. doi:10.36076/ppj.2014/17/E319

 PubMed Web of Science ®Google Scholar

Juch JNS, Maas ET, Ostelo RWJG, et al. Effect of radiofrequency denervation on pain intensity among patients with chronic low back pain: the mint randomized clinical trials. JAMA. 2017;318(1):68–81.

 PubMed Web of Science ®Google Scholar

Nath S, Nath CA, Pettersson K. Percutaneous lumbar zygapophysial (facet) joint neurotomy using radiofrequency current, in the management of chronic low back pain: a randomized double-blind trial. Spine (Phila Pa 1976). 2008;33(12):1291–1297; discussion 1298. doi:10.1097/BRS.0b013e31817329f0

 Web of Science ®Google Scholar

Tekin I, Mirzai H, Ok G, Erbuyun K, Vatansever D. A comparison of conventional and pulsed radiofrequency denervation in the treatment of chronic facet joint pain. Clin J Pain. 2007;23(6):524–529. doi:10.1097/AJP.0b013e318074c99c

 PubMed Web of Science ®Google Scholar

van Wijk RMAW, Geurts JWM, Wynne HJ, et al. Radiofrequency denervation of lumbar facet joints in the treatment of chronic low back pain: a randomized, double-blind, sham lesion-controlled trial. Clin J Pain. 2005;21(4):335–344. doi:10.1097/01.ajp.0000120792.69705.c9

 PubMed Web of Science ®Google Scholar

van Kleef M, Barendse GA, Kessels A, Voets HM, Weber WE, de Lange S. Randomized trial of radiofrequency lumbar facet denervation for chronic low back pain. Spine (Phila Pa 1976). 1999;24(18):1937–1942. doi:10.1097/00007632-199909150-00013

 Web of Science ®Google Scholar

Çetin A, Yektaş A. Evaluation of the short- and long-term effectiveness of pulsed radiofrequency and conventional radiofrequency performed for medial branch block in patients with lumbar facet joint pain. Pain Res Manag. 2018;43(2):76–80.

 Google Scholar

Lakemeier S, Lind M, Schultz W, et al. A comparison of intraarticular lumbar facet joint steroid injections and lumbar facet joint radiofrequency denervation in the treatment of low back pain: a randomized, controlled, double-blind trial. Anesth Analg. 2013;117(1):228–235. doi:10.1213/ANE.0b013e3182910c4d

 PubMed Web of Science ®Google Scholar

Dobrogowski J, Wrzosek A, Wordliczek J. Radiofrequency denervation with or without addition of pentoxifylline or methylprednisolone for chronic lumbar zygapophysial joint pain. Pharmacol Rep. 2005;57(4):475–480.

 Web of Science ®Google Scholar

McCormick ZL, Choi H, Reddy R, et al. Randomized prospective trial of cooled versus traditional radiofrequency ablation of the medial branch nerves for the treatment of lumbar facet joint pain. Reg Anesth Pain Med. 2019;44(3):389–397. doi:10.1136/rapm-2018-000035

 PubMed Web of Science ®Google Scholar

Moon JY, Lee PB, Kim YC, Choi SP, Sim WS. An alternative distal approach for the lumbar medial branch radiofrequency denervation: a prospective randomized comparative study. Anesth Analg. 2013;116(5):1133–1140. doi:10.1213/ANE.0b013e31828b35fe

 Web of Science ®Google Scholar

Moussa WMM, Khedr W. Percutaneous radiofrequency facet capsule denervation as an alternative target in lumbar facet syndrome. Clin Neurol Neurosurg. 2016;150:96–104. doi:10.1016/j.clineuro.2016.09.004

 PubMed Web of Science ®Google Scholar

Song K, Li Z, Shuang F, et al. Comparison of the effectiveness of radiofrequency neurotomy and endoscopic neurotomy of lumbar medial branch for facetogenic chronic low back pain: a randomized controlled trial. World Neurosurg. 2019;126:e109–e115. doi:10.1016/j.wneu.2019.01.251

 PubMed Web of Science ®Google Scholar