Peripheral Neuromodulation for Chronic Pain

Peripheral Nervous System Pain Modulation

The percutaneous technique of electrode insertion in the vicinity of the greater occipital nerves to treat occipital neuralgia was first described in the 1990s by Weiner and Reed. This subsequently stimulated awareness of peripheral nerve stimulation (PNS). The more recent advent emergence of a minimally invasive percutaneous approach by way of using ultrasound has further increased the interest in PNS as a viable alternative to more invasive techniques. PNS has become more popular recently and is increasingly used to treat various pain conditions. Its foundation is fundamentally based on the gate control theory, although the precise mechanism underlying its analgesic effect is still indefinite. Studies have demonstrated the peripheral and central analgesic mechanisms of PNS by modulating the inflammatory pathways, the autonomic nervous system, the endogenous pain inhibition pathways, and the involvement of the cortical and subcortical areas. Peripheral nerve stimulation exhibits its neuromodulatory effect both peripherally and centrally. Further understanding of the modulation of PNS mechanisms can help guide stimulation approaches and parameters to optimize the use of PNS. his chapter aims to review the background and mechanisms of PNS modulation. PNS is becoming one of the most diverse therapies in neuromodulation due to rapid evolution and expansion. It is an attractive option for clinicians due to the simplicity and versatility of procedures that can be combined with other neuromodulation treatments or used alone. It has a distinct role in the modulation of functional conditions.

Rehabilitation of Peripheral Neuropathies: From Lexical Analysis of the Literature to Identification of Clinical Protocols

Peripheral nervous system diseases are a complex and heterogenous group of diseases affecting the different nerves with various severity and impact on quality of life. The current literature does not provide a structured guide for the rehabilitation of these conditions. We performed a lexical literature evaluation based on graph theory to clarify this topic. We performed a search on PubMed and calculated the frequencies of the words indicating rehabilitation approaches, nerves, and diseases. We found the usefulness of exercises and different physical agents, like laser and ultrasound therapy and neuromuscular stimulation vibration therapy. Orthoses are useful for entrapment, trauma, and hereditary diseases. Correct knowledge and assessment of the neuropathies are fundamental for the therapeutic decision and to guide rehabilitation. Despite the usefulness shown by the different approaches to modulating pain, improving muscle strength and endurance, and ameliorating balance and the sensory system, further studies are needed to define the best-personalized protocols.

Evidence-Based Clinical Guidelines from the American Society of Pain and Neuroscience for the Use of Implantable Peripheral Nerve Stimulation in the Treatment of Chronic Pain

The objective of this peripheral nerve stimulation consensus guideline is to add to the current family of consensus practice guidelines and incorporate a systematic review process. The published literature was searched from relevant electronic databases, including PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science from database inception to March 29, 2021. Inclusion criteria encompassed studies that described peripheral nerve stimulation in patients in terms of clinical outcomes for various pain conditions, physiological mechanism of action, surgical technique, technique of placement, and adverse events. Twenty randomized controlled trials and 33 prospective observational studies were included in the systematic review process. There is Level I evidence supporting the efficacy of PNS for treatment of chronic migraine headaches via occipital nerve stimulation; chronic hemiplegic shoulder pain via stimulation of nerves innervating the trapezius, supraspinatus, and deltoid muscles; failed back surgery syndrome via subcutaneous peripheral field stimulation; and lower extremity neuropathic and lower extremity post-amputation pain. Evidence from current Level I studies combined with newer technologies facilitating less invasive and easier electrode placement make peripheral nerve stimulation an attractive alternative for managing patients with complex pain disorders. Peripheral nerve stimulation should be used judiciously as an adjunct for chronic and acute postoperative pain following adequate patient screening and positive diagnostic nerve block or stimulation trial.