Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation for Postoperative Analgesia

The moderate-to-severe pain many patients experience after orthopedic surgery is often treated with opioids, which are associated with undesirable adverse effects such as nausea, vomiting, sedation, and respiratory depression. Potent site-specific analgesia with far fewer adverse effects may be provided with a continuous peripheral nerve block. Unfortunately, perineural infusion has its own set of limitations such as inducing motor, sensory, and proprioception deficits that possibly increase the risk of falling; limited duration due to the risk of infection; and, for ambulatory patients, the burden of carrying an infusion pump and local anesthetic reservoir. These, among other, limitations have led some leaders in regional anesthesia to conclude that this technique is often “effective, but unrealistic”; and calls within the surgical literature to abandon continuous peripheral nerve blocks. There is new evidence that suggests an analgesic alternative—ultrasoundguided percutaneous peripheral nerve stimulation (pPNS)—holds promise to provide postoperative analgesia free of many of the major limitations of both opioid analgesics and continuous peripheral nerve blocks. The concept of using electrical stimulation to induce analgesia is hardly new: the ancient Romans prescribed contact with a living torpedo fish—able to deliver up to 220 V of current—as an analgesic; and this technique continued to be recommended through the Middle Ages up until at least the 16th century for a wide variety of pain-inducing ailments. Electroanalgesia continued to evolve through the 18th century with the discovery of artificial means to produce electrical current, with the first device specifically designed for this purpose—the “Electreat”—produced in the early 1900s. Subsequently, the first implantable spinal cord stimulator was described in 1967, with the first implantable peripheral nerve stimulator following a year later.