Components of a Spinal Cord Stimulation System

Implantable Devices Used to Block or Modify Nerve Pain

Spinal cord stimulation (SCS) is a medical technique used to deliver mild electrical pulses to nerves along the spine to modify or block pain signals to the brain.

SCS was first used to treat pain in 1967 and later approved for use by the U.S. Food and Drug Administration in 1989 to relieve pain caused by nerve damage in the trunk, arms, or legs (including lower back pain, leg pain, and failed back surgery).

The device is implanted near the spinal column and functions similarly to a cardiac pacemaker. In place of pain, a person will typically feel a light pins-and-needles sensation. Newer systems, like the Senza stimulation system approved in 2015, have been able to largely overcome this effect.

The SCS system consists of four components that work together to deliver electrical stimulation to the source of the pain (also known as the pain generator). Most devices today weigh a little more than an ounce and are comprised of a pulse generator, electrical leads, a remote control, and battery recharger.

1

Implantable Pulse Generator

Implantable Pulse Generator
Courtesy Boston Scientific

The implantable pulse generator (IPG) is the central component of any SCS system. It is roughly the size of a vanilla wafer and is surgically implanted via either the abdomen or buttock area. Electrical leads are then run from the IPG to the epidural space in the spinal canal.

The epidural space is the area between the covering of the spine (called the dura mater) and the vertebral wall. It is where anesthetic medications are commonly injected to block pain during pregnancy.

Most IPGs today are powered by a rechargeable battery, although traditional, non-rechargeable units are still in use.

2

Leads and Electrodes

leads for spinal cord stimulation system
Courtesy Boston Scientific

The leads of an SCS system are essentially insulated wires emanating from the IPG that receive and deliver the electrical pulses. They are not unlike car jumper cables used to transfer electricity from a live battery to a dead one.

At the end of each lead is an electrode which is inserted into the epidural space. There are two main types of leads:

  • Percutaneous leads (percutaneous meaning "under the skin") which are inserted into soft tissue with a simple incision
  • Surgical leads which, as their name implies, are inserted during back surgery
3

Remote Control

Remote control for spinal cord stimulation system
Courtesy Boston Scientific

Newers IPGs are designed so that you can control the level of stimulation to a certain degree. This is done by using a remote control device programmed to your specific unit.

A remote control can be vital for making adjustments if your IPG is ever affected by electromagnetic interference (EMI). This can happen if ever you are close to equipment, such as airport security devices, that generate a strong electromagnetic field. When hit by EMI, an IPG can turn off or increase to a level where the electrical pulse is uncomfortably strong.

A remote allows you to temporarily adjust or switch off the unit if needed. Unlike a pacemaker, which can't be turned off, a spinal cord stimulator can.

4

Battery Recharger

Battery recharger for a spinal cord stimulation system
Courtesy Boston Scientific

There are few IPGs used today that are not rechargeable, and it's clear why. Older, non-rechargeable units have a battery life of between two and five years. Newer ones can last 10 to 25 years, offering users greater freedom and far fewer surgical interventions.

The IPG battery is recharged by placing the cordless recharger on the skin directly over the unit. It is held in place by an adjustable belt strap and usually takes several hours each week to fully recharge. A beep and/or light indicator will tell you when the battery is fully recharged.

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Article Sources
  • U.S. Food and Drug Administration (FDA). "FDA approves spinal cord stimulation system that treats pain without tingling sensation." Silver Spring, Maryland; issued May 8, 2015.
  • FDA, "Premarket Approval: Itrel Totally Implantable Spinal Cord Stimulation System." January 21, 1989.