De Ridder 2013.

Study characteristics
Methods	Study design: randomised controlled trial Study grouping: cross‐over Analysis: not described Sample size calculation: not described Study design: a randomised placebo‐controlled trial; tonic versus burst versus sham immediate‐term outcomes Trial aim: to find out whether SCS is indeed capable of suppressing neuropathic limb pain in a placebo‐controlled way Trial duration: conducted from 1 January 2011 until 30 September 2011. 1 week with burst mode, 1 week in tonic mode, and 1 week with placebo
Participants	Baseline characteristics Overall Age: mean (SD) = 54.0 years (8.6) Sex: female = 11 (73%), male = 4 (27%) Pain duration: not reported Baseline back pain score: mean (0‐10) = 7.35 (2.49) Baseline function score: not reported QOL score: not reported Baseline leg pain score: mean (0‐10) = 7.50 (1.63) Work status: not measured Pain medication use: not measured Healthcare use: not measured Number of participants: 15 Diagnostic criteria: "who presented to the BRAI2N neuro‐modulation clinic were eligible for SCS according to the Belgian requirements for the reimbursement for SCS, which states that the patient has to be medically intractable to opioids and antiepileptic drugs. All patients were selected by the first author, and after a multidisciplinary discussion with a specialized pain physician, a psychological and psychiatric evaluation was performed to rule out psychogenic pain as well as other psychiatric morbidity contraindicating an implant." Socioeconomic status: not measured Inclusion criteria: extracted from clinicaltrials.gov/ct2/show/record/NCT01486108. able to provide informed consent to participate in the study; between the age of 18 and 75; has FBSS; has a simulator implanted at the dorsal column spinal cord powered by an EON/EON Mini internal pulse generator; medication has remained stable for at least 4 weeks prior to baseline data collection; agrees not to add or increase medication throughout the randomisation trial period of the study; willing to cooperate with the study requirements including compliance with the treatment regimen and completion of all office visits. Exclusion criteria: "A patient will be excluded from participation in this study if they meet any one of the following criteria": current evidence of any psychiatric disorder; history of life‐threatening severe illness or is suffering from severe chronic disease other than the indication for the study; history of substance abuse or substance dependency in the past 6 months prior to baseline data collection; currently participating in another clinical study; has a demand‐type cardiac pacemaker, an infusion pump, or any other implantable neurostimulator device except for the spinal cord stimulator under study; not willing to maintain current medication regimen; female candidates of child bearing potential who are pregnant (confirmed by positive urine/blood pregnancy test), not using adequate contraception as determined by the investigator, or nursing (lactating) a child. Pretreatment: n/a (cross‐over) Minimum pain intensity: not stated, only that "Belgian requirements for the reimbursement for SCS, which states that the patient has to be medically intractable to opioids and antiepileptic drugs." Number of participants: 15 Source of participants: Antwerp University Hospital. "All patients were selected by the first author, and after a multidisciplinary discussion with a specialized pain physician, a psychological and psychiatric evaluation was performed to rule out psychogenic pain as well as other psychiatric morbidity contraindicating an implant. After authorization by the psychologist and psychiatrist, an implant was offered to the patient"; presented to the BRAI2N neuro‐modulation clinic
Interventions	Placebo Frequency: zero amplitude (IPG not discharging) Stimulator type: stimulation was performed with a nonsterile EON IPG System (St. Jude Medical) via externalised extension wires Lead number and type: Lamitrode tripole, 88, penta, 44 Manufacturer: St Jude Medical Description: placebo stimulation was performed in the following way: burst stimulation was applied on the predefined electrode contacts until the participant experienced paraesthesia. Subsequently the stimulator intensity was decreased exactly like in burst programming but continued until zero amplitude Burst or tonic stimulation: not applicable Duration: 1 week Co‐interventions: not reported Conventional spinal cord stimulation Frequency: classical tonic stimulation (40 Hz or 50 Hz) Stimulator type: stimulation was performed with a nonsterile EON IPG System (St. Jude Medical) via externalised extension wires Lead number and type: Lamitrode tripole, 88, penta, 44 Manufacturer: St Jude Medical Description: stimulation intensity for tonic and burst mode during randomised stimulation was selected on the basis of the maximal pain suppression as determined by the participant Burst or tonic stimulation: tonic Duration: 1 week Co‐interventions: not reported Burst spinal cord stimulation Frequency: "Burst stimulation consists of intermittent packets of closely spaced, high‐frequency stimuli, for instance, 40‐Hz burst mode with five spikes at 500 Hz per burst, with a pulse width of 1 ms [1000 µs] and 1‐ms interspike intervals delivered in constant current mode. The cumulative charge of the five 1‐ms spikes is balanced during 5 ms after the spikes, which differentiates it from high‐frequency clustered firing, in which each pulse is immediately charge balanced" Stimulator type: EON IPG System (St Jude Medical) Lead number and type: Lamitrode tripole, 88, penta, 44 Manufacturer: St Jude Medical Description: "The stimulation intensity for tonic and burst mode during randomized stimulation was selected on the basis of the maximal pain suppression as determined by the patient. The burst mode was programmed by use of a custom‐made software and programming device. Typically, burst stimulation is characterized by a lower amplitude but larger pulse width, which results in a similar energy delivery per pulse. In burst mode, the amplitude was increased up to the moment that paraesthesias were elicited. Subsequently, the amplitude was decreased to a level below paraesthesia threshold." Burst or tonic stimulation: burst Duration: 1 week Co‐interventions: not reported
Outcomes	Outcomes measured at one week (immediate‐term outcome) Outcomes included in review Back pain intensity (100 mm VAS) Leg pain intensity (100 mm VAS); both measured at immediate outcome time points Outcomes excluded from review 100 mm VAS for "general pain", worst pain, least pain during past week Preoccupation with or attention to pain (Pain vigilance and awareness questionnaire) Paraesthesias caused by the stimulation Electroencephalogram and source localisation
Identification	Sponsorship source: none stated Country: Belgium Setting: Neuromodulation clinic; approved by the Antwerp University Hospital Institutional review board Comments: "Conflict of interest statement: Dr. De Ridder has obtained a patent for burst stimulation. The remaining authors have no conflicts of interest." Author's name: Dirk De Ridder Institution: Department of Surgical Sciences, Section of Neurosurgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand Email: dirk.deridder@otago.ac.nz Address: Department of Surgical Sciences, Section of Neurosurgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand Start date ‐ End date: conducted from 1 January 2011 until 30 September 2011 Trial registration: registered at ClinicalTrials.gov (NCT01486108).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: report states that study is randomised, but provides no detail on method of sequence generation.
Allocation concealment (selection bias)	Unclear risk	Comment: no mention of allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: differences in paraesthesia tonic vs placebo but not burst vs placebo. Participants able to identify when active treatment being received.
Blinding of outcome assessment (detection bias) Self‐reported outcomes	High risk	Comment: subjective measures of paraesthesia reported by participants. Participants able to identify when active treatment being received.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "All 15 patients were included in the study" Comment: all participants recruited completed the study.
Selective reporting (reporting bias)	Low risk	Comment: outcomes appear to reflect what is reported in trial registry.
Other bias	High risk	Comment: no mention of dealing with period and carry‐over effects and no methods employed to mitigate for these factors.