Study Comparing Conventional, Burst and High Frequency (HF) Spinal Cord Stimulation (SCS) in Refractory Failed Back Surgery Syndrome (FBSS) Patients After a 32-contact Surgical Lead Implantation

Prospective, Randomized Study Comparing Conventional, Burst And High Frequency (HF) Spinal Cord Stimulation (SCS) in Refractory Failed Back Surgery Syndrome (FBSS) Patients After a 32-contact Surgical Lead Implantation

Chronic Back and/or Leg Pain (CBLP) after spinal surgical procedures, a condition commonly labelled Failed Back Surgery Syndrome (FBSS), affects between 15% and 40% of patients after a spine surgery. Treatment of this chronic condition by further operation or medical management has a heavy financial impact on health care systems.

Many studies have demonstrated the efficacy and economic value of Spinal Cord Stimulation (SCS) for chronic neuropathic pain, and randomized controlled trials (RCTs) have shown SCS to be a clinically effective adjunct to medical management. SCS has the advantages of being reversible and less invasive than surgery and may cause fewer issues over time than long-term pharmacological treatments.

Despite variable levels of success in the literature, approximately 30-55% of the patients treated with traditional SCS for neuropathic pain disorders will not receive adequate long term pain relief. Therefore, technical SCS system refinements, as well as new techniques have emerged.

Two new stimulation waveforms based on traditional SCS technology have appeared to further optimize the outcome for specific painful conditions;

• Burst stimulation mode: which generates constant-current stimuli with 5 spikes at 500 Hz per burst and pulse width and interspike intervals of 1 ms.
• High-frequency stimulation (from 1 to 10 kHz) mode.

Several studies have demonstrated the potential interest of these 2 new waveforms to treat FBSS patients compared to traditional SCS.

The Precision Spectra™ system allows MultiWave Technology by offering a broad spectrum of waveform options (from Tonic Conventional Stimulation (TCS), BURST stimulation to High Frequency stimulation (HF)).

To date, literature data comparing these 3 stimulation patterns is lacking but it is suggested the pain relief in some of non-responsive patients can be "recaptured" by increasing the SCS frequency to 500 Hz by BURST stimulation or beyond by HF stimulation. It seems important to conduct RCT in crossover, thanks to the new Precision SCS Stimulator, to compare the effects of these 3 different SCS modalities in FBSS patients and to determine which concept is the most effective in terms of pain reduction and energy consumption.

Inclusion Criteria:

• Age ≥ 18 years or ≤ 80 years.
• Subject has FBSS and does not require further surgery. For the purposes of this study, FBSS is defined as persistent or recurrent low back and leg pain of at least 6 months duration following at least one decompression and/or fusion procedure.
• Subject has persistent low back and leg pain despite other treatment modalities (pharmacological, surgical, physical, or psychological therapies) that have been tried and did not prove satisfactory or are unsuitable or contraindicated for the subject.
• Average global pain is ≥ 50 mm as assessed by the baseline VAS.
• With significant back, with mean intensity on a back pain VAS ≥ 50 mm (mean daily VAS score calculated on 5 consecutive days).
• Meeting the criteria for spinal cord stimulation test according to HAS guidelines (multidisciplinary consultation, psychological assessment, etc.).
• Subject is a candidate for SCS.
• Absence of active psychosis or history of serious psychotic illness requiring hospitalisation.
• Understands and accepts the constraints of the study.
• Free subject, not under temporary or permanent guardianship and not subject to subordination.
• Patients covered by French national health insurance.
• Patients who have given their written consent to the study after having received clear information.

Exclusion Criteria:

• Age < 18 years or > 80 years
• Subject is or has been treated with SCS, subcutaneous or peripheral nerve stimulation, an intrathecal drug delivery system, requires back surgery at the location related to his/her original back pain complaint or experimental therapies.
• Cause of low back pain accessible to etiological "mechanical" surgical treatment (discogenic low back pain, vertebral instability, spinal deformity, etc.).
• Subject had most recent back surgery less than 6 months ago.
• Presenting a surgical, anaesthetic or psychiatric contraindication to implantation of a spinal cord stimulation system.
• Based on the opinion of the principal or sub-investigator, the subject is unable to operate the SCS equipment.
• Subject has a life expectancy of less than 24 months beyond study enrolment.
• Absence of signature of the informed consent form.
• Patients not covered by French national health insurance.
• Subjects requiring closer protection, i.e. minors, pregnant women, nursing mothers, subjects deprived of their freedom by a court or administrative decision, subjects admitted to a health or social welfare establishment, major subjects under legal protection, and finally patients in an emergency setting.
• Pregnant women, nursing mothers, women of childbearing potential not using effective contraception (hormonal/barrier: oral, parenteral, percutaneous, implantable, intrauterine device, or surgical: tubal ligation, hysterectomy, total ovariectomy).