Chronic pain management with rechargeable spinal cord stimulators

In March and April of 2005, the Food and Drug Administration gave its approval to two implantable devices that patients can recharge on their own:

• Eon™ Neurostimulation System
  Advanced Neuromodulation Systems’ Eon device consists of leads (placed above the spinal cord), a small generator/receiver (implanted under the skin) and a programmer/transmitter that also allows for remote control of stimulation intensity. The battery life is currently estimated at seven years, and the company plans to submit data to the FDA in order to receive support for an even longer battery life claim.

• RESTORE™ Rechargeable Neurostimulation System
  Medtronic’s device, called the Restore Rechargeable Neurostimulation System, uses a battery with an estimated nine-year total life span. When batteries run low, patients using the device will hear an alarm go off and see an icon appear on the programmer screen. In order to recharge, they will need to use a recharger that they can carry in a pouch on their body. It takes about six hours to fully recharge the batteries and the activity should usually be repeated once each month.

• Precision™ Spinal Cord Stimulation System
  Boston Scientific’s Precision device consists of leads and a generator that are implanted under the skin and external parts (a remote control, a charger and charging station) and its battery life is estimated at five years. Recharging takes a few hours and requires placing a portable cordless recharger over the implant.

Pain relief trial
Before a patient commits to a full system implantation, he or she will likely have a stimulation trial in order to make sure that spinal cord stimulation is likely to provide pain relief for the patient. During such a trial, one or several leads are implanted into the patient’s lower back for a short period of time (usually several days) and are connected to a temporary spinal cord stimulator. A trial stimulator contains up to several stimulation programs with the goal of providing optimal treatment for the patient, customized to fit the patient’s needs. If trial therapy provides sufficient relief from pain, which may differ in individual cases, the patient can be scheduled for another procedure and receive permanent implants. In the case of an unsuccessful trial when stimulation does not bring desired effects, the trial system will be removed and other treatment options analyzed.

Cost of rechargeable spinal cord stimulators
The initial cost of the rechargeable stimulators is expected to be more than that of non-rechargeable devices. While non-rechargeable stimulators sell for about $15,000, the cost of new stimulators is expected to amount to approximately $17,000. Both Medicare and private insurance are expected to cover the rechargeable devices mentioned in this article, if appropriate indications are met.

Spinal cord stimulator side effects
Implantable rechargeable spine stimulators with prolonged battery life are a new option for treatment of neuropathic chronic pain. The primary benefit of this technology is that it is expected to decrease the number of replacement surgeries needed. It is important to remember, however, that it is not designed to improve the efficacy of a spinal cord stimulator in terms of managing a patient’s pain.

While the risk of complications with implantable spinal cord stimulators is low relative to many other more invasive surgical procedures, and the stimulation systems may be removed at any time, it is important for patients to talk to their doctors abut any possible risk factors and side effects that may include:

• Bleeding

• Allergic reactions

• Paralysis

• Numbness

• Consistent pain around the implant area

• Battery failure or leakage

• Post surgical soreness

• Tolerance to stimulation secondary to scar formation over time.

By: Thomas M. Wascher, MD, FACS
September 23, 2005