The Clinician’s Manual must be reviewed prior to use of the Neurostimulation System for detailed disclosure.
Indications for Use
The Eon™, EonC™, and Eon Mini™ implantable pulse generator (IPG) Neurostimulation Systems are indicated for spinal cord stimulation (SCS) as aids in the management of chronic intractable pain of the trunk and/or limbs including unilateral or bilateral pain associated with any of the following: failed back surgery syndrome, and intractable low back and leg pain.
The system is contraindicated for patients who are unable to operate the system or who have failed to receive effective pain relief during trial stimulation.
The following warnings apply to the use of the Neurostimulation System.
Poor surgical risks. Neurostimulation should not be used on patients who are poor surgical risks or patients with multiple illnesses or active general infections.
Diathermy therapy. Do not use short-wave diathermy, microwave diathermy, or therapeutic ultrasound diathermy (all now referred to as diathermy) on patients implanted with a neurostimulation system. Energy from diathermy can be transferred through the implanted system and cause tissue damage at the location of the implanted electrodes, resulting in severe injury or death.
Diathermy is further prohibited because it may also damage the neurostimulation system components. This damage could result in loss of therapy, requiring additional surgery for system implantation and replacement. Injury or damage can occur during diathermy treatment whether the neurostimulation system is turned on or off. All patients are advised to inform their healthcare professionals that they should not be exposed to diathermy treatment.
Electrosurgery devices. Electrosurgery devices should not be used in close proximity to an implanted neurostimulation system. Contact between an active electrode and an implanted IPG, lead, or extension can cause direct stimulation of the spinal cord and severe injury to the patient. If use of electrocautery is necessary, first turn off the neurostimulation system.
Implanted cardiac systems. Physicians need to be aware of the risk and possible interaction between a neurostimulation system and an implanted cardiac system, such as a pacemaker or defibrillator. Electrical pulses from a neurostimulation system may interact with the sensing operation of an implanted cardiac system, causing the cardiac system to respond inappropriately. To minimize or prevent the implanted cardiac system from sensing the output of the neurostimulation system, (1) verify that the neurostimulation system is not interfering with the functions of the implanted cardiac system and (2) avoid programming either device in a unipolar mode (using the device’s can as an anode).
Magnetic resonance imaging (MRI). Patients with implanted neurostimulation systems should not be subjected to MRI. The electromagnetic field generated by an MRI may forcefully dislodge implanted components, damage the device electronics, and induce voltage through the lead that could jolt or shock the patient.
Explosive or flammable gases. Do not use the patient programmer in an environment where explosive or flammable gas fumes or vapors are present. The operation of the patient programmer could cause them to ignite, causing severe burns, injury, or death.
Operation of machinery and equipment. Patients should not operate potentially dangerous machinery, power tools, or vehicles or climb things like ladders when the IPG is operating. Postural changes or abrupt movement could alter the perception of stimulation intensity and cause patients to fall or lose control of equipment or vehicles, injure others, or bring injury upon themselves.
Pediatric use. Safety and effectiveness of neurostimulation for pediatric use have not been established.
Pregnancy. Safety and effectiveness of neurostimulation for use during pregnancy and nursing have not been established.
Device components. The use of non-St. Jude Medical Neuromodulation Division components with this system may result in damage to the system and increased risk to the patient. Case damage. If the IPG case is pierced or ruptured, severe burns could result from exposure to battery chemicals.
Component disposal. Return all explanted IPGs to St. Jude Medical Neuromodulation Division for safe disposal (see “Disposing of Explanted Components”). IPGs contain lithium ion batteries as well as other potentially hazardous materials. Do not crush, puncture, or burn the IPG because explosion or fire may result.
Product materials. Neurostimulation systems have materials that come in contact or may come in contact with tissue. A physician should determine whether or not a patient may have an allergic reaction to these materials
before the system is implanted.
The following precautions apply to the use of the Neurostimulation System.
Physician training. Implanting physicians should be experienced in the diagnosis and treatment of chronic pain syndromes and have undergone surgical and device implantation training.
Patient selection. It is extremely important to select patients appropriately for neurostimulation. Thorough psychiatric screening should be performed. Patients should not be dependent on drugs and should be able to operate the neurostimulation system.
Infection. It is important to follow proper infection control procedures. Infections related to system implantation might require that the device be explanted.
Implantation of two systems. If two systems are implanted, ensure that at least 20 cm (8 in) separates the implanted IPGs to minimize the possibility of interference during programming.
Implantation of multiple leads. If multiple leads are implanted, leads and extensions should be routed in close proximity. Nonadjacent leads can possibly create a conduit for stray electromagnetic energy that could cause the patient unwanted stimulation.
Implant heating. While recharging an IPG, patients may perceive an increase in temperature. In patients who have areas of increased sensitivity to heat, consider placing the implant where the patient has normal sensation.
High stimulation outputs. Stimulation at high outputs may cause unpleasant sensations or motor disturbances or may render the patient incapable of controlling the patient programmer. If unpleasant sensations occur, the device should be turned off immediately.
Postural changes. Changes in posture or abrupt movements may result in a decrease or increase in the perceived level of stimulation. Perception of higher levels of stimulation has been described by some patients as uncomfortable, painful, or jolting. Patients should be advised to turn down the amplitude or turn off the IPG before making extreme posture changes or abrupt movements such as stretching, lifting their arms over their heads, or exercising. If unpleasant sensations occur, the IPG should be turned off immediately.
Theft detectors and metal screening devices. Certain types of antitheft devices, such as those used at entrances/exits of department stores, libraries, and other public establishments, and/or airport security screening devices may affect stimulation. It is possible that patients who are implanted with nonadjacent multiple leads and/or patients who are sensitive to low stimulation thresholds may experience a momentary increase in their perceived stimulation, which has been described by some patients as uncomfortable or jolting. It is recommended that patients use caution when approaching such a device and that they request assistance to bypass the device. If they must proceed through the device, patients should turn off the IPG and proceed with caution, being sure to move through the detector quickly.
Lead movement. Patients should be instructed to avoid bending, twisting, stretching, or lifting objects over five pounds for six to eight weeks after implantation of a neurostimulation system. Extension of the upper torso or neck may cause lead movement and alter the stimulation field (especially with leads in the cervical area), resulting in overstimulation or ineffective stimulation.
Stimulation parameters. Patients should be cautioned that stimulation parameters must be determined under the supervision of a physician and that they should not adjust stimulation parameters within prescribed programs unless ordered to do so by a physician.
Mobile phones. The effect of mobile phones on neurostimulation systems is unknown; patients should avoid placing mobile phones directly over the system.
Sterilization and Storage
Single-use, sterile device. The implanted components of the Eon Mini neurostimulation system are intended for a single use only. Do not resterilize or reimplant an explanted system for any reason because of the risk of infection and device malfunction.
Storage temperature. Store system components between -10°C and 55°C (14°F and 131°F). Temperatures outside this range can damage components.
Storage humidity. Store components between 10% and 90% humidity.
Storage environment. Store components and their packaging where they will not come in contact with liquids of any kind.
Handling and Implementation
Expiration date. Do not implant a device if the use-before date has expired.
Care and handling of components. Use extreme care when handling system components prior to implantation. Excessive heat, excessive traction, excessive bending, excessive twisting, or the use of sharp instruments may damage and cause failure of the components.
Package or component damage. Do not implant a device if the sterile package or components show signs of damage, if the sterile seal is ruptured, or if contamination is suspected for any reason. Return any suspect components to St. Jude Medical Neuromodulation Division for evaluation.
Exposure to body fluids or saline. Prior to connection, exposure of the metal contacts, such as those on the connection end of a lead or extension, to body fluids or saline can lead to corrosion. If such exposure occurs, clean the affected parts with sterile, deionized water or sterile water for irrigation, and dry them completely prior to lead connection and implantation.
System testing. To ensure correct operation, the system should always be tested after implantation and before the patient leaves the surgery suite.
Hospital and Medical Environments
High-output ultrasonics and lithotripsy. The use of high-output devices, such as an electrohydraulic lithotriptor, may cause damage to the electronic circuitry of an implanted IPG. If lithotripsy must be used, do not focus the energy near the IPG.
Ultrasonic scanning equipment. The use of ultrasonic scanning equipment may cause mechanical damage to an implanted neurostimulation system if used directly over the implanted system.
External defibrillators. The safety of discharge of an external defibrillator on patients with implanted neurostimulation systems has not been established.
Therapeutic radiation. Therapeutic radiation may damage the electronic circuitry of an implanted neurostimulation system, although no testing has been done and no definite information on radiation effects is available. Sources of therapeutic radiation include therapeutic X rays, cobalt machines, and linear accelerators. If radiation therapy is required, the area over the implanted IPG should be shielded with lead.
Home and Occupational Environments
Electromagnetic interference (EMI). Certain commercial electrical equipment (for example, arc welders, induction furnaces, and resistance welders), communication equipment (for example, microwave transmitters, linear power amplifiers, and high-power amateur transmitters), and high-voltage power lines may generate sufficient EMI to interfere with the operation of the neurostimulation system if approached too closely.
The implantation of a neurostimulation system involves risk. In addition to those risks commonly associated with surgery, the following risks are also associated with implantation and/or use of a neurostimulation system:
- Stimulation at high outputs may cause unpleasant sensations or motor disturbances, including involuntary movement. If either occurs, turn off your IPG immediately.
- Undesirable changes in stimulation may occur over time. These changes may be related to cellular changes in tissue around the electrodes, changes in electrode position, loose electrical connections, and/or lead failure.
- Stimulation may occur in unwanted places, such as the radicular (nerve root) chest wall area.
- A lead can move and result in changes in stimulation and/or a reduction in pain relief.
- Placement of a lead in the epidural space may cause epidural hemorrhage, hematoma, infection, spinal cord compression, and/or paralysis.
- Cerebrospinal fl uid (CSF) leakage is possible.
- Paralysis, weakness, clumsiness, numbness, and/or pain below the level of the implant can occur.
- Persistent pain may occur at the electrode or IPG site.
- Seroma (mass or swelling) may occur at the IPG site.
- Implant materials may cause an allergic or rejection response.
- The implant can move, or skin can erode from around it.
- Battery failure and/or battery leakage is possible.