Study reference

Study characteristics

Patient characteristics

Intervention (I)

Comparison / control (C)

Follow-up

Outcome measures and effect size

Comments

Van Zundert, 2007

Type of study:

RCT

Setting and country:

Patients that were referred to the pain centers of the University Hospital Maastricht, Maastricht, The Netherlands; Ziekenhuis Oost-Limburg, Genk, Belgium, and Catharina Hospital, Eindhoven, The Netherlands, were screened for inclusion.

Funding and conflicts of interest:

None declared.

Inclusion criteria:

- Neck pain radiating over the posterior shoulder area to the arm for >6 months.

- Conventional therapy, including medication, physical therapy, and transcutaneous electrical nerve stimulation, was not effective.

- Symptoms should suggest involvement of the cervical spinal nerve and be perceived along the affected nerve root.

- Positive Spurling test.

- Average pain intensity (VAS) > 35.

Exclusion criteria:

- Age <20 years or >75 years.

- History of cancer.

- Fractures of the cervical vertebrae.

- Myelopathy.

- Previous cervical fusion or laminectomy.

- Systemic diseases or connective tissue diseases.

- Diabetes mellitus.

- Coagulation disorders and use of anticoagulants.

- Multiple sclerosis.

- Pregnancy.

- Shoulder pathology.

- Presence of a cardiac pacemaker or spinal cord stimulator.

- Previous RF or PRF treatment of the cervical DRG.

N total at baseline:

I: 11

C: 12

Important prognostic factors:

Age ± SD:

I: 42 ± 12.2

C: 52.9 ± 11.9

Sex (%male):

I: 46%

C: 42%

Groups comparable at baseline? No, patients in the control group were older and started with a higher VAS score.

Describe intervention:

PRF treatment

- Stimulation was started at 50 Hz to obtain a sensory stimulation threshold.

- The PRF current was applied during 120 s from the lesion generator.

Describe control:

Sham treatment during which the identification of the target point, electrode placement, and the sensory stimulation was performed in the same way as for the patients in the intervention group.

Length of follow-up:

6 months

Loss-to-follow-up:

Intervention: none before 3 months

Reasons: -

Control: 1 before 3 months

Reasons: surgical treatment

Incomplete outcome data:

Not reported, except loss-to-follow-up as above.

Outcome measures and effect size:

Pain

Defined as a 20-points reduction in pain intensity measured by VAS after 3 months

I: 82% (9/11)

C: 25% (3/12)

Patient satisfaction

Defined as at least 50% pain improvement of the GPE

4 weeks

I: 64% (7/11)

C: 42% (5/12)

3 months

I: 82% (9/11)

C: 33% (4/12)

6 months

I: 64% (7/11)

C: 17% (2/12)

Complications

Defined as the number of participants that reported side effects or complications over the study period

I: 0

C: 0

Medication use

Defined as the change in intake of pain medication from baseline to 3 months

Higher

I: 9.1% (1/11)

C: 41.7% (5/12)

Equal

I: 36.4% (4/11)

C: 25.0% (3/12)

Lower

I: 54.5% (6/11)

C: 33.3% (4/12)

Functioning

SF-36, defined as the mean difference (SD) at 3 months

Physical functioning

I: 9.0 (16.6)

C: 6.9 (15.0)

Social functioning

I: 12.5 (28.0)

C: -1.0 (28.4)

Quality of life

Euroqol, defined as the mean difference (SD) at 3 months

I: 12.6 (19.7)

C: 4.7 (30.8)

SF-36, defined as the mean difference (SD) at 3 months

Physical role restriction

I: 23.5 (48.6)

C: 24.3 (26.9)

Emotional role restriction

I: 24.2 (36.8)

C: 0.0 (53.7)

Mental health

I: 6.9 (12.9)

C: 0.3 (22.2)

Vitality

I: 17.3 (17.1)

C: 2.1 (16.0)

Pain

I: 9.8 (20.5)

C: 9.3 (25.8)

General health

I: 4.1 (10.0)

C: 2.3 (19.0)

Cervical surgery

Defined as the number of participants that were referred for neck surgery

I: 9% (1/11)

C: 25% (3/12)

Authors conclusion:

PRF treatment of the cervical dorsal root ganglion might provide pain relief for a limited number of patients with chronic cervical radicular pain.

Limitations:

- Difference in baseline demographic characteristics.

- Low inclusion rate, resulting in not enough power for different parameters.

Lee, 2016

Type of study:

RCT

Setting and country:

Department of Physical Medicine & Rehabilitation,

Dongsan Medical Center, Keimyung University

School of Medicine, Daegu, Korea,

Department of

Physical Medicine & Rehabilitation, Yeungnam

University School of Medicine, Daegu, Korea.

Funding and conflicts of interest:

The study was supported by the 2015 Yeungnam University Research Grant. The authors had no potential conflicts of interest to disclose.

Inclusion criteria:

- Age between 20 and 70 years.

- Presentation with symptomatic cervical or lumbar radicular pain.

- Imaging findings of a cervical or lumbar intervertebral disc pathology compatible with pain symptoms.

- Severe cervical or lumbar radicular pain than cervical or lumbar axial pain.

- Presentation with a VAS of >4 and an ODI or Neck Disability Index of >30% after first TFESI.

Exclusion criteria:

- Severe allergy to injectants.

- History of spine surgery.

- Spinal instability.

- Spinal stenosis or degenerative spondylolisthesis.

- Infection on the spine.

- Tumor or tumor metastasis in the involved spinal area.

- Pregnancy.

N total at baseline:

I: 19

C: 19

Important prognostic factors:

Age ± SD:

I: 54.3 ± 12.1

C: 50.8 ± 12.7

Sex (%male):

I: 16%

C: 58%

Groups comparable at baseline? No, percentage male differed between the two groups.

Describe intervention:

PRF therapy:

- The catheter needle was inserted, and a sensory stimulation test was carried out using an RF generator.

- Treatment was administered at 5 Hz and a 5 ms pulsed width for 240 seconds at 45V.

Describe control:

Transforaminal epidural steroid injection:

- Patients received 2 mL of 0.125% bupivacaine mixed with 5 mg dexamethasone.

Length of follow-up:

3 months

Loss-to-follow-up:

Total: 6

Reasons: drop-out (n=5), flare up pain (n=1).

Incomplete outcome data:

Not reported, except loss-to-follow-up as above.

Outcome measures and effect size:

Pain

Defined as pain intensities, assessed by VAS, mean (SD)

Pre-treatment

I: 5.3 (1.2)

C: 4.9 (0.8)

2 weeks

I: 4.2 (1.3)

C: 3.6 (1.2)

4 weeks

I: 3.3 (1.1)

C: 2.8 (1.3)

8 weeks

I: 2.4 (0.9)

C: 2.5 (2.1)

3 months

I: 2.0 (0.8)

C: 2.4 (2.3)

Complications

I: 5.3% (1/19)

C: 0% (0/19)

Functioning

Defined as functional disabilities associated with cervical radicular pain, assessed by NDI, mean (SD)

Pre-treatment

I: 38.7 (8.3)

C: 39.1 (11.6)

2 weeks

I: 28.3 (14.7)

C: 28.6 (9.7)

4 weeks

I: 22.2 (11.6)

C: 19.4 (11.2)

8 weeks

I: 17.6 (6.8)

C: 18.8 (15.7)

3 months

I: 14.0 (7.0)

C: 17.0 (14.3)

Authors conclusion:

PRF treatment can be considered as a useful option for the control of radicular pain that helps reduce or avoid the possible adverse effects of TFESI.

Limitations:

- Small sample size

Other remarks:

Subgroup analyses for cervical radicular patients are available.

Halim, 2017

Type of study:

RCT

Setting and country:

Anna Hospital, Geldrop, The Netherlands, Radboud UMC Medical Center, Nijmegen, The Netherlands.

Funding and conflicts of interest:

No funding reported. The institution one author works for receives study grants from Cotera Inc and Zimmer Biomet Inc, and he is a consultant for Zimmer Biomet, but this is unrelated to the current study.

Inclusion criteria:

- Patients with a contained, single-level cervical disk herniation diagnosed on recent MRI (<4 weeks) who failed conservative treatment.

- Presentation with a 100 mm VAS of >50 mm with or without neck pain corresponding to the herniated level.

- Disk height over 50% of adjacent level.

Exclusion criteria:

- Patients who did not respond to a diagnostic nerve block placed with local anesthetic at the level identified with history taking and MRI.

- Extruded disk fragmentation.

- Cervical spondylolisthesis.

- Spinal canal stenosis.

- Previous surgery at the index cervical disk herniation level.

N total at baseline:

I: 17

C: 17

Important prognostic factors:

Age ± SD:

I: 49.5

C: 52.4

Sex (%male):

I: 53%

C: 41%

Groups comparable at baseline? Yes.

Describe intervention:

PRF treatment:

- A 45 V, 2 Hz (20 ms) PRF stimulus was applied for 6 minutes.

Describe control:

Percutaneous nucleoplasty treatment

Length of follow-up:

3 months

Loss-to-follow-up:

Intervention: 7

Reasons: no reason provided

Control: 3

Reasons: no reason provided

Incomplete outcome data:

No other than loss-to-follow-up reported above.

Outcome measures and effect size:

Pain

Baseline

I: 69.5

C: 71.0

1 month

I: 41.0

C: 29.3

2 months

I: 38.0

C: 31.5

3 months

I: 35.5

C: 27.6

Patient satisfaction

1 month

I: 52.8

C: 68.9

2 months

I: 60.9

C: 67.8

3 months

I: 63.5

C: 58.4

Complications

I: 18% (3/17)

C: 18% (3/17)

Functioning

Baseline

I: 19.4

C: 21.1

1 month

I: 14.9

C: 15.9

2 months

I: 12.2

C: 12.3

3 months

I: 10.8

C: 11.1

Authors conclusion:

Both PRF and PCN treatment show significant pain improvement in patients with contained cervical disk herniation, but none of the treatments is superior to the other. Both treatment options are shown to be effective and safe for use in clinical practice.

Limitations:

- Comparison of two active treatments.

- Limited follow-up of 3 months.

- Small sample size.

Wang, 2016

Type of study:

Randomized comparative study

Setting and country:

Pain Management Department of Shenzhen Nanshan Hospital in China.

Funding and conflicts of interest:

No conflicts of interest to declare. Nothing is mentioned about funding.

Inclusion criteria:

- Age >20 years

- Males and females

- Moderate to severe chronic cervical radicular pain (NRS > 5)

- Resistance to conservative management

- No indication for open surgical intervention

- MRI evidence of nerve root compression

- Absence of progressive motor deficit

Exclusion criteria:

- Uncorrected coagulopathy

- Infection

- Cervical myelopathy

- Malignancy

- Bilateral or more than one level radicular pain

- Previous cervical fusion or laminectomy

- Significant psychopathology

N total at baseline:

I: 20

C: 21

Important prognostic factors:

Age ± SD:

I: 58.4 ± 16.2

C: 59.0 ± 13.8

Sex (%male):

I: 55%

C: 43%

Groups comparable at baseline? Yes.

Describe intervention:

PRF treatment:

- At 42 degrees Celsius, the PRF stimulus was applied for 4 minutes, and then radiculography was carried out.

Describe control:

The control (CNRB) group received a mixture of 1 mL corticosteroids containing 5 mg betamethasone dipropionate and 2 mg betamethasone disodium phosphate, 1 mL 0.9% NaCl, and 1 mL of 2% lidocaine after radiculography.

Length of follow-up:

6 months

Loss-to-follow-up:

Intervention: 1

Reasons: NR

Control: 2

Reasons: NR

Incomplete outcome data:

Not reported, except loss-to-follow-up as above.

Outcome measures and effect size:

Patient satisfaction

Defined as rates of positive GPE (+2 or +3)

1 week

I: 20% (4/20)

C: 23.8% (5/21)

1 month

I: 40% (8/20)

C: 14.3% (3/21)

3 months

I: 5.3% (1/19)

C: 14.3% (3/21)

6 months

I: 10.5% (2/19)

C: 5.3% (1/19)

Complications

Defined as the number of patients with complications

I: 0

C: 0

Authors conclusion:

Combining PRF and CNRB achieved superior outcomes to those accomplished by either CNRB or PRF alone.

Limitations:

- Small sample size

- Short follow-up to determine long-term effects

Chalermkitpanit, 2023

Type of study:

RCT

Setting and country:

King Chulalongkorn Memorial Hospital

(KCMH), Bangkok, Thailand

Funding and conflicts of interest:

The study was funded by a grant from Ratchadapisek-sompotch Fund, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. The authors had no potential conflicts of interest to disclose.

Inclusion criteria:

- Age between 30-80 years.

- Diagnosis of cervical spondylosis with radicular pain by an orthopaedic surgeon and a pain specialist.

- Clinical examination compatible with MRI.

- Moderate to severe cervical radicular pain rated by a NRS at least 4 out of 10.

- Chronic pain >3 months despite conservative treatment.

Exclusion criteria:

- Cervical radiculopathy with progressive weakness.

- Radicular pain secondary to spinal tumor.

- Patients with cardiac device implantation.

- Ongoing local infection at the injection area or systemic infection.

- Patients with bleeding disorders.

- History of allergy to study medications.

N total at baseline:

I: 20

C: 21

Important prognostic factors:

Age ± SD:

I: 48.9 ± 15.8

C: 56.3 ± 14.6

Sex (%male):

I: 40%

C: 38%

Groups comparable at baseline? Yes.

Describe intervention:

PRF treatment:

- Treatment was done for 4 minutes following a positive sensory stimulation between 0.3 and 0.5 volts. After the PRF treatment, 1.5 mL of 2% lidocaine with 10 mg of dexamethasone was injected.

Describe control:

Steroid treatment:

- A short bevel stimulating 22G-needle was placed and the sensory stimulation was confirmed. Then the same injectate was administered.

Length of follow-up:

9 months

Loss-to-follow-up:

Intervention: 1

Reasons: not reported.

Control: -

Reasons: -

Incomplete outcome data:

No other than loss-to-follow-up reported above.

Outcome measures and effect size:

Pain

NRS, mean (SD)

I: 2.8 (2.7)

C: 5.5 (2.6)

Functioning

NDI, mean differences between PRF and steroid group

3 months: 23.0 (95%CI 9.6 to -36.4)

6 months: 23.8 (95%CI 4.2 to 43.3)

Authors conclusion:

PRF treatment exhibited a neuromodulation effect and is shown to be effective for patients with cervical radicular pain.

Limitations:

- Small sample size.

Study reference

(first author, publication year)

Was the allocation sequence adequately generated?

Was the allocation adequately concealed?

Blinding: Was knowledge of the allocated

interventions adequately prevented? Were patients/healthcare providers/data collectors/outcome assessors/data analysts blinded?

Was loss to follow-up (missing outcome data) infrequent?

Are reports of the study free of selective outcome reporting?

Was the study apparently free of other problems that could put it at a risk of bias?

Overall risk of bias

If applicable/necessary, per outcome measure

Van Zundert, 2007

Definitely yes

Reason: A computer-generated randomization list was used.

Definitely yes

Reason: Independent observer provided the treating physician with a sealed envelope numbered in advance, which was opened in the operating room.

Definitely yes

Reason: Patients, independent observer, data manager and neurologist were blinded. The healthcare provider was not blinded.

Definitely yes

Reason: Only one (8%) participant was lost to follow-up before three months from the control group for a valid reason (surgery).

Probably yes

Reason: No registration in register of clinical trials mentioned, but no reason to doubt that the report is free of selective outcome reporting.

Definitely no

Reason:

- Differences in baseline demographic characteristics.

- Underpowering for different parameters, due to the low number of included participants.

Some concerns (underpowering due to small sample size)

Lee, 2016

Unknown

Unknown

Unknown

Probably no

Reason: five patients (12%) were lost to follow-up (no reason reported) and one patient dropped out due to a pain flare-up.

Probably yes

Reason: No registration in register of clinical trials known. Study protocol has been written but is not available.

Probably yes

Reason:

- Small sample size.

Some concerns (information is missing)

Halim, 2017

Unknown

Unknown

Unknown

Definitely no

Reason: three patients (15%) were lost to follow-up from PCN group (no reason reported), and seven (29%) patients were lost to follow-up from PRF group (no reason reported).

Probably no

Reason: No registration in register of clinical trials mentioned. Some outcomes mentioned in the methods section are not reported in the results section.

Probably yes

Reason:

- Small sample size.

High

Wang, 2016

Definitely no

Reason: Patients were randomized according to the last number of their medical record number, which was generated by two research fellows.

Definitely no

Reason: The same research fellows assigned participants to interventions.

Definitely no

Reason: Data collectors (two nurses) were the only ones blinded.

Probably yes

Reason: two patients (10%) were lost to follow-up from CNRB group (no reason), and one patient (5%) was lost to follow-up from PRF group (no reason).

Probably yes

Reason: No registration in register of clinical trials known. Study protocol has been written but is not available.

Probably yes

Reason:

- Small sample size.

High

Chalermkitpanit, 2023

Unknown

Unknown

Probably yes

Reason: Double-blinded RCT; patients and pain assessors were blinded.

Probably yes

Reason: Only one (5%) participant was lost to follow-up at 1 month, but no reason was reported.

Probably yes

Reason: No registration in register of clinical trials mentioned, but no reason to doubt that the report is free of selective outcome reporting.

Probably yes

Reason:

- Small sample size.

Some concerns (information is missing)