In The Battle Against Pain: How Peripheral Nerve Stimulation Is Changing The Game For Clinicians And Patients With Nerve Pain

Chronic pain affects as many as 100 million Americans yearly and is an enormous economic burden. Traditional pain management methods, such as opioids, often come with a host of adverse side effects that can lead to further disability and reduced quality of life. Neuromodulation is a rapidly advancing field of medicine with the potential to change the way we treat pain. Neuromodulation uses electricity to modulate pain from the central or peripheral nervous system; it can reduce or even eliminate pain-related aberrant firing of nerves. Spinal cord stimulation (SCS) involves the placement of long, multi-contact leads in the epidural space in the spine to modulate pain signaling in the spinal cord. In peripheral nerve stimulation (PNS), smaller, more compact stimulating electrodes are placed adjacent to peripheral nerves. Most commercially available PNS devices utilize an external wearable that powers the device and provides electrical impulses to the implanted lead.

Traditional PNS systems initially implanted in the 1960s were large, cumbersome, and fraught with complications like lead fracture, migration, and erosion. PNS has evolved from an open surgical procedure to a percutaneous, minimally invasive neuromodulation technique that effectively reduces pain and improves function in patients with chronic pain. Additionally, patients who receive peripheral nerve stimulation require less medication, on average, than those who do not. This can lead to improved quality of life and reduced disability. As our understanding of neuromodulation grows, this technique may become increasingly popular as a treatment for chronic pain.

One of the most agonizing physical pains a person can experience is phantom limb pain (PLP). This occurs when an individual loses a limb but continues to feel sensation in the missing appendage. The pain can be sharp and shooting, or it can be a dull, throbbing ache. Physical therapy is often used to help retrain the brain and reduce pain signals. Desensitization techniques may also help to lessen the pain. PNS has recently been shown to be an effective treatment in patients with PLP, even when a lead was placed temporarily and peripheral nerves were stimulated for only two months. The proposed reasons for why PNS is helpful are still under investigation, but both peripheral mechanisms (modulation of the injured nerve) as well as central mechanisms (changes in neuroplasticity in the spinal cord and brain), are considered thought to be responsible.

Perhaps the most significant evolution in PNS technology is the minimally invasive nature of these devices. Before 2015, most PNS technology was an adaptation from bulky SCS systems, which required the implantation of a large impulse generator (battery) and the use of leads that were not designed to be placed near small-diameter peripheral nerves. Over the past seven years, there has been a rapid evolution and release of PNS systems with various lead sizes, configurations, and stimulation waveforms. Temporary and permanent options exist depending on a patient’s pain trajectory. To mitigate the challenges of a sizeable implantable battery/power source, current PNS systems utilize external wearables that power and provide stimulation to the internalized lead or impulse generator. 

Radiofrequency technology or induction currents are utilized by several devices to generate stimulation to the distal lead electrodes. 

Because of the compact design of these systems, most PNS systems can be implanted with local anesthesia only with ultrasound or fluoroscopic guidance. For patients who are considered high risk for SCS (those on chronic anticoagulants, prior spine surgery, or significant medical comorbidities), PNS can serve as an alternative, particularly in patients with localized pain.

As PNS technology continues to develop, so will the indications for treatment and patients who will benefit. This fascinating field is experiencing a modern-day renaissance, and it is an exciting time to be a part of its evolution.

Brief Biography

Scott G. Pritzlaff, MD, is an interventional pain specialist at the University of California, Davis. He currently serves as a Clinical Associate Professor in the Department of Anesthesiology and Program Director for the Pain Medicine Fellowship. After graduating from medical school at Georgetown University, he spent five years on active duty as a Naval physician. He completed his internship at the Walter Reed National Military Medical Center. From 2008-2010, he deployed twice to Iraq and Afghanistan with the 2nd Marine Aircraft Wing in support of coalition combat operations. He then finished anesthesiology training at the Massachusetts General Hospital, followed by a clinical pain management fellowship at Stanford. Dr. Pritzlaff’s research interests focus on using ultrasound and emerging technologies to treat peripheral neuropathic pain. He is interested in developing novel uses of percutaneous peripheral nerve stimulation to treat chronic nerve pain.

Representative publications to consider:

1. Strand N, D’Souza RS, Hagedorn JM, Pritzlaff S, Sayed D, Azeem N, Abd-Elsayed A, Escobar A, Huntoon MA, Lam CM, Deer TR. 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. J Pain Res. 2022 Aug 23;15:2483-2504. doi: 10.2147/JPR.S362204. PMID: 36039168; PMCID: PMC9419727.

2. Kalia H, Pritzlaff S, Li AH, Ottestad E, Gulati A, Makous J, Chakravarthy K. Application of the novel Nalu™ Neurostimulation System for peripheral nerve stimulation. Pain Manag. 2022 Aug 10. doi: 10.2217/pmt-2021-0050. Epub ahead of print. PMID: 35946308.

3. Jung MJ, Pritzlaff SG. Peripheral Nerve Stimulation for Treatment of Severe Refractory Upper Extremity Post-Amputation Pain. Neuromodulation. 2021 Aug;24(6):1127-1128. doi: 10.1111/ner.13246. Epub 2020 Jul 30. PMID: 32734623.

4. Jung MJ, Pritzlaff SG. Peripheral Nerve Stimulation of Complex Upper Extremity Amputation Pain May Be Variable. A A Pract. 2021 Apr 1;15(4):e01441. doi: 10.1213/XAA.0000000000001441. PMID: 33793432.

5. Hanyu-Deutmeyer A, Pritzlaff SG. Peripheral Nerve Stimulation for the 21st Century: Sural, Superficial Peroneal, and Tibial Nerves. Pain Med. 2020 Aug 1;21(Suppl 1):S64-S67. doi: 10.1093/pm/pnaa202. PMID: 32804232.

(I can give more specific details here if this is of interest- we have published on this recently)