Peripheral nerve stimulation has been used in the treatment of several chronic pain conditions including pain due to peripheral nerve dysfunctions, complex regional pain syndrome, and cranial neuralgias. It has been shown to be effective for chronic, intractable pain that is refractory to conventional therapies such as physical therapy, medications, transcutaneous electrical stimulations, and nerve blocks. Recently, a new generation of peripheral nerve stimulation devices has been developed; these allow external pulse generators to transmit impulses wirelessly to the implanted electrode, and their implantation is significantly less invasive. In this review, we discuss the history, pathophysiology, indications, implantation process,and outcomes of employing peripheral nerve stimulation to treat chronic pain conditions.
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Power is provided to the implanted wireless lead by external pulse generators that are wearable in belts, fabric, jewelry, etc. This technique eliminates the need for an implantable pulse generator (IPG) and tunneling of the electrodes to the IPG, thereby reducing the expense and morbidities. The use of this technology has been evaluated in a study of acute postoperative pain from total knee arthroplasty . Ilfeld et al. inserted percutaneous peripheral nerve electrodes using ultrasound guidance in close proximity to the femoral and/or sciatic nerve(s). With the delivery of current, pain decreased an average of 63% at rest, with four of the five subjects having relief > 50%. The study was funded by SPR Therapeutics.
In agreement with those results, Deer et al. demonstrated in a prospective, multicenter, randomized, double-blinded, partial crossover study that a peripheral nerve stimulator with an external power source provided significant relief compared to control in patients with severe intractable chronic pain of peripheral nerve origin [37–40]. In this study, 94 patients were implanted and then randomized to the treatment (N=45) or the control group (N=49). The patients who received active stimulation achieved a statistically significant higher response rate of 38% versus the 10% found in the control group ( < 0.0048). The mean pain reduction was 27.2% from baseline compared to a 2.3% reduction in the control group ( < 0.0001). During the partial crossover period, the treatment group again demonstrated statistically significant improvement in pain relief. This study was funded by Bioness Inc., manufacturer of the StimRouter.
The authors thank Dr. Marina De Tommaso and an anonymous reviewer of the ‘Pain Research and Treatment’ for very helpful critical reviews, which significantly improved our manuscript. This work was supported by the Department of Anesthesiology, University of Minnesota.
©2018 Raghavendra Nayak and Ratan K.Banik.