Medical Policy: 07.01.78
Original Effective Date: October 2018
Reviewed: October 2018
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This Medical Policy document describes the status of medical technology at the time the document was developed. Since that time, new technology may have emerged or new medical literature may have been published. This Medical Policy will be reviewed regularly and be updated as scientific and medical literature becomes available.
Implantable peripheral nerve stimulation for chronic pain of peripheral nerve origin is a type of neuromodulation therapy that involves the surgical implantation of electrodes that target peripheral nerves considered to be the origin of pain. This procedure differs from other forms of peripheral nerve stimulation, because of the origin of pain is from a peripheral nerve and the electrical impulses are delivered to the nerve versus surrounding tissues or the spine.
Implantable peripheral nerve stimulation varies from other electrical stimulation therapies:
Chronic pain originating in peripheral nerves has very variable presentation, and often unclear etiology and as a result treatment is challenging. First-line pain management typically involves pharmacotherapy (NSAIDs, steroids, anti-depressants) and physical therapy. However, many patients do not achieve sufficient relief. Second and third-line options include therapeutic injections (epidural steroid injections, nerve blocks, trigger point injections), intrathecal drug pumps to deliver drugs directly to nerve centers and neurostimulation with electric pulses to override pain signals. Implantable peripheral nerve stimulation is being utilized for management of chronic pain of peripheral origin to treat upper/lower limb pain, entrapment syndromes, intercostal neuralgias and other peripheral injuries or diseases.
As with other types of implantable nerve stimulation, implantation of the peripheral nerve stimulator is typically a two-step process. Initially, the electrode is temporarily implanted allowing a trial period of stimulation typically up to a week. The temporary electrode is connected to an external power source that the patient controls. Once treatment effectiveness is confirmed, defined as at least 50% reduction in pain, the permanent placement of electrode are implanted which is connected either to an implanted pulse generator or the implanted electrode responds to a wireless system using an external radiofrequency transmitter.
Evidence reviews assess the clinical evidence to determine whether the use of technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function – including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcomes is a balance of benefits and harms.
To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative treatments at a comparable intensity. The quality and credibility of the evidence depend on the study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances non-randomized studies may be adequate.
The principal outcomes associated with the treatment of pain due to any cause includes: relief of pain, improved function and improved quality of life. Relief of pain can be a subjective outcome associated with a placebo effect (improvement of the patient’s condition simply because the person has the expectation that the treatment they are receiving might be helpful). Therefore, data from adequately powered, blinded, randomized controlled trials (RCTs) are required to determine if an implanted peripheral nerve stimulation system for chronic pain of peripheral nerve origin provides management changes and improves net health outcomes. Studies should also compare peripheral nerve stimulation with other neurostimulation such as spinal cord stimulation and alternative treatments with long term outcomes to assess safety and effectiveness.
There were no systematic reviews identified.
The majority of the literature related to implantable peripheral nerve stimulation for various conditions (e.g. treatment of hemiplegic shoulder pain; peripheral neuropathic pain; intercostal neuralgia; back pain; neck pain; occipital neuralgia; postherpetic neuralgia; and trigeminal neuralgia/trigeminal neuropathic pain) is case series. While case series are appropriate for introducing novel interventions, they have inherent limitations. Results may be generalized, there are no controls, outcomes are not blinded, assessor bias cannot be ruled out, no comparative information to alternative treatments and no long term follow-up. These case series may show promising results, however, to be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative treatment(s) at a comparable intensity with long term follow-up to verify safety and efficacy.
In 2012, Silberstein et. al. published a randomized, controlled, double-blinded multicenter study on the safety and efficacy of peripheral nerve stimulation (PNS) of the occipital nerves for the management of chronic migraine in 157 patients. The patients were randomized to active treatment (n=105) or sham treatment (n=52). The primary endpoint was a difference in the percentage of responders (defined as patients that achieved a ≥50% reduction in mean daily visual analog scale scores) in each group at 12 weeks. There was not a significant difference in the percentage of responders in the Active compared with the Control group (95% lower confidence bound (LCB) of -0.06; p = 0.55). However, there was a significant difference in the percentage of patients that achieved a 30% reduction (p = 0.01). Importantly, compared with sham-treated patients, there were also significant differences in reduction of number of headache days (Active Group = 6.1, baseline = 22.4; Control Group = 3.0, baseline = 20.1; p = 0.008), migraine-related disability (p = 0.001) and direct reports of pain relief (p = 0.001). The most common adverse event was persistent implant site pain. The authors concluded, although this study failed to meet its primary endpoint, this is the first large scale study of (PNS) of the occipital nerves in chronic migraine patients that showed significant reductions in pain, headache days, and migraine-related disability. Additional controlled studies are warranted in this highly disabled patient population with a large unmet medical need.
In 2016, Deer et. al. published a prospective, multicenter, randomized, double-blinded, partial crossover study to assess the safety and efficacy of the StimRouter neuromodulation system in the treatment of 94 patients with chronic pain of peripheral nerve origin. After IRB approval, patients were enrolled, implanted, and then followed for three months to assess efficacy and one year for safety based on Food and Drug Administration guidance. The patients were randomized to the treatment StimRouter group (45) or the control group (n=49). The primary efficacy endpoint, three months after randomization to treatment, demonstrated that patients receiving active stimulation achieved a statistically significantly higher response rate of 38% vs. the 10% rate found in the Control group (p = 0.0048). Improvement in pain was statistically significant between the randomized groups, with the Treatment group achieving a mean pain reduction of 27.2% from Baseline to Month 3 compared to a 2.3% reduction in the Control group (p < 0.0001). During the partial crossover period, patients again demonstrated statistically significant improvement in pain relief with active stimulation compared to baseline. Further, the treatment group had significantly better improvement than the control group in secondary measures including but not limited to quality of life and satisfaction. Safety, assessed throughout the trial and with follow-up to one year, demonstrated no serious adverse events related to the device. All device-related adverse events were minor and self-limiting. However, the results need confirmation in additional randomized controlled trials (RCTs) with longer follow-up to draw conclusions. Studies should also compare StimRouter with other peripheral nerve stimulation systems such as spinal cord stimulation and alternative treatments.
A prospective, multi-center, single-arm study that will include 50 participants to assess StimRouter’s effectiveness for treating severe intractable chronic shoulder pain subsequent to stroke. The primary endpoint will be a clinically relevant pain reduction (30%) in pain score at 3 months after initiating stimulation in at least 50% of patients with no increase in pain medication. Expected completion September of 2019 (NCT03093935). This study will not provide the data needed to confirm efficacy and safety because it has no control group, and chronic pain waxes and wanes over time, pain is a subjective measure, and single-arm study design will have a high risk of bias so that results cannot be reliably attributed to the intervention.
In 2010, Deer et. al. published the results of prospective, single-center, open-label trial in which eight patients with carpal tunnel syndrome were evaluated for pain relief from the StimRouter. Primary endpoints were successful implantation near the target peripheral nerve and safety. All 8 patients were implanted temporarily at the median nerve in at least one arm and 2 patients were implanted bilaterally, with 10 implants total. Each implant was considered a separate "patient." For 5 days, all patients received 6 hours of daily transdermal electrical stimulation targeting the median nerve. Pain was measured at baseline, during implant, and after explant. Two patients experienced clinically meaningful (>or=30%) pain reduction throughout the entire 5-day treatment period. Apparent carryover effect in pain reduction also was observed after daily stimulation. After explant, pain returned to baseline, increasing 36.8% to 45.6% relative to average reduced pain with daily stimulation. No significant or unexpected adverse events occurred. The authors concluded temporary implant of the StimRouter device resulted in both pain reduction and reduced use of oral opioid pain medication during the 5 day stimulation period. The results suggest that permanent implant of the StimRouter System may be safe and effective for treating chronic peripheral neuoropathic pain. Limitation of this study includes small sample size and no long term follow-up after StimRouter explant.
Based on review of the peer reviewed medical literature the evidence is limited to two randomized controlled trials, nonrandomized trial, and case series that suggests implantable peripheral nerve stimulation is safe and works as intended to treat chronic pain of peripheral nerve origin. However, results need confirmation in additional randomized controlled trials (RCTs) with longer follow-up to draw conclusions on safety and efficacy. Further studies should also compare implantable peripheral nerve stimulation with other neuromostimulation therapy such as spinal cord stimulation and alternative treatments. There are no evidence based clinical practice guidelines that recommend the use of implantable peripheral nerve stimulation for the treatment of chronic pain of peripheral nerve origin. The evidence is insufficient to determine the effects of this technology on net health outcomes.
There are no evidence based clinical practice guidelines that recommend the use of implanted peripheral nerve stimulation for the treatment of pain of peripheral nerve origin.
In February 2015 the U.S. Food and Drug Administration (FDA) granted 510(k) marketing clearance for the StimRouter Neuromodulation System (Bioness, Inc., Valencia, CA). The StimRouter Neuromodulation System is indicated for pain management in adults who have severe intractable pain of peripheral nerve origin, as an adjunct to other modes of therapy (e.g. medications). The StimRouter is not intended to treat pain in the craniofacial region.
In March 2016 the U.S. Food and Drug Administration (FDA) granted 510(k) marketing clearance for the StimQ Peripheral Nerve Stimulator (PNS) System (Stimwave LLC, Pompano Beach, FL). The StimQ Peripheral Nerve Stimulator (PNS) System is indicated for pain management in adults who have severe intractable chronic pain of peripheral nerve origin, as the sole mitigating agent, or as an adjunct to other modes of therapy used in a multidisciplinary approach. The therapy utilizes pulsed electrical current to create an electrical energy field that acts on peripheral nerves in the limbs and torso to alter transmission of pain signals to the brain. The StimQ PNS system is not intended to treat pain in the craniofacial region. The StimQ Trial Lead Kit is only used in conjunction with the StimQ Stimulator Receiver Kit. The trial devices are solely used for trial stimulation (no longer than 30 days) to determine efficacy before recommendation for a permanent (long term) device.
In August 2017, the U.S. Food and Drug Administration (FDA) granted 510(k) marketing clearance for StimQ wireless peripheral nerve stimulator system. This device can be placed minimally-invasive, provides pain relief by delivering small pulses of energy to electrodes placed at a peripheral nerve enabling the brain to remap the pain signals. The implant is powered by a small external unit.
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Implantable peripheral nerve stimulation to include temporary and permanent placement for the management of chronic pain of peripheral origin is investigational for all indications including but not limited to the following:
Based on review of the peer reviewed medical literature the evidence is limited to two randomized controlled trials, nonrandomized trial, and case series that suggests implantable peripheral nerve stimulation is safe and works as intended to treat chronic pain of peripheral nerve origin. However, results need confirmation in additional randomized controlled trials (RCTs) with longer follow-up to draw conclusions on safety and efficacy. Further studies should also compare implantable peripheral nerve stimulation with other neuromodulation therapy such as spinal cord stimulation and alternative treatments. There are no evidence based clinical practice guidelines that recommend the use of implantable peripheral nerve stimulation for the treatment of chronic pain of peripheral nerve origin. The evidence is insufficient to determine the effects of this technology on net health outcomes.
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