A peripheral nerve stimulator (PNS) is a type of medical device that is used to treat chronic back pain, particularly pain that originates from the nerves in the back or legs. The device works by delivering electrical impulses to the peripheral nerves that are responsible for transmitting pain signals to the brain.

The PNS system consists of a small pulse generator and a lead with electrodes. The pulse generator is usually implanted under the skin near the area of pain, and the lead with electrodes is positioned next to the peripheral nerve that is causing the pain.

Once the device is in place, it is programmed by a healthcare professional to deliver electrical impulses at specific frequencies and intensities to target the patient's pain. The patient may be able to adjust the stimulation level using a handheld remote control.

PNS is typically used to treat chronic back pain caused by a variety of conditions, including complex regional pain syndrome, peripheral neuropathy, and other nerve-related conditions. The procedure is generally considered safe, but as with any surgical procedure, there are potential risks and complications, such as infection, bleeding, or device failure.

Patients who have a PNS implanted should also be aware of potential side effects, such as pain at the site of implantation, numbness, tingling, or muscle spasms. It's important to discuss the risks and benefits of PNS with your healthcare provider to determine if it's an appropriate treatment option for your specific condition and needs.