Important Safety Information
St. Jude Medical™ Invisible Trial System
Prescription and Safety Information
Read this section to gather important prescription and safety information.
Indications for Use
The St. Jude Medical™ Invisible Trial System is indicated as an aid 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 St. Jude Medical™ Invisible Trial System is intended to be used externally with St. Jude Medical-approved trial leads and extensions to deliver trial stimulation for a maximum of 30 days.
This neurostimulation system is contraindicated for patients who are unable to use the system.
Neurostimulation should not be used on patients who are poor surgical risks, such as those with multiple illnesses or active general infections.
The following warnings apply to these components.
Other system components. Refer to the individual system component manuals for additional warnings and precautions related to those devices.
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.
Explosive or flammable gases. Do not use the stimulator in an environment where explosive or flammable gas fumes or vapors are present, including hyperbaric chambers. The operation of the stimulator could cause them to ignite, causing severe burns, injury or death.
Electrosurgery devices. Electrosurgery devices should not be used in close proximity to an implanted neurostimulation device. Contact between an active electrode and an implanted lead or extension can cause direct stimulation of the tissue at the electrode site and cause severe injury to the patient. If use of electrocautery is necessary, first turn off the neurostimulation system.
Implanted cardiac system. 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) maximize the distance between the implanted systems; (2) verify that the neurostimulation system is not interfering with the functions of the implanted cardiac system; and (3) avoid programming either device in a unipolar mode (using the device’s can as an anode) or using neurostimulation system settings that interfere with the functions of the implantable cardiac system.
Magnetic resonance imaging (MRI). Patients with an EPG should not be subjected to MRI. Even if the leads are removed the patient should not have an MRI if any part of a lead is still implanted.
Lead movement. Patients should avoid bending, twisting, stretching, or lifting objects over five pounds for six to eight weeks postimplantation. Extension of the upper torso or neck may cause lead movement and alter the stimulation field, resulting in overstimulation or ineffective stimulation.
Operation of machines, equipment, and vehicles. Patients should not drive or operate heavy machinery or power tools with the stimulator turned on. Postural changes or abrupt movement could cause overstimulation (jolting sensation) that might cause patients to lose control of their vehicle or equipment.
Postural changes. Changes in posture or abrupt movements can change the level of stimulation and potentially cause unpleasant sensations. Patients should turn stimulation off or lower the amplitude before stretching, lifting their arms over their head, or exercising. If unpleasant sensations occur, turn off stimulation.
Pediatric use. Safety and effectiveness of neurostimulation for pediatric use have not been established.
Pregnancy and nursing. Safety and effectiveness of neurostimulation for use during pregnancy and nursing have not been established.
System components. The use of non St. Jude Medical™ components with this system may result in damage to the system and increased risk to the patient.
Power supply. Use only the CR2450 batteries supplied with the device. CR2450 batteries have a nominal voltage of 3V and nominal capacity of at least 600 mAh.
The following precautions apply to these components.
Clinician Training. Clinicians should be experienced in implanting neurostimulation devices and should have undergone sufficient 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. Follow proper infection control procedures and inform patients to avoid showering and touching the bandages.
Theft detectors and metal screening devices. Certain types of antitheft devices, such as those used at entrances or exits of department stores, libraries, and other public establishments, and airport security screening devices may affect stimulation. Patients who are implanted with nonadjacent multiple leads and 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. Patients should use caution when approaching such a device and should request assistance to bypass the device. If they must proceed through the device, patients should turn off the EPG and proceed with caution, being sure to move through the detector quickly.
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.
Handling and Implementation
Single use only. The EPG header is intended for single use only.
Exposure to liquids. Device components should be stored where they will not be exposed to liquids or excessive moisture, which can damage the package materials and components.
Care and handling of components. Use extreme care when handling system components prior to use. Excessive heat, traction, bending, and twisting, or the use of sharp instruments may damage components and cause them to fail.
Package or component damage. Do not use the device if the package or components show signs of damage. Return any suspect components to St. Jude Medical for evaluation.
System testing. To ensure correct operation, the system should always be tested before the patient leaves the surgery suite.
Device modification. The equipment is not serviceable by the customer. To prevent injury or damage to the system, do not modify the equipment. If needed, return the equipment to St. Jude Medical for service.
Component disposal. Dispose of the EPG header and pouch with other medical waste. Return the EPG to St. Jude Medical for safe disposal when necessary.
Hospital and Medical Environments
Therapeutic radiation may damage the electronic circuitry of a 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, computerized tomography (CT) scans, cobalt machines, and linear accelerators. If radiation therapy is required, disconnect the EPG from the leads or extensions. Damage to the system may not be immediately detectable.
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), high voltage power lines, and radio-frequency identification (RFID) devices may generate sufficient EMI to interfere with the operation of the neurostimulation system if approached too closely. Keep the neurostimulation system at least 10 cm (4 in) away from RFID devices.
The effect of mobile phones on neurostimulation systems is unknown; patients should avoid placing mobile phones directly over the system.
The use of a neurostimulation system involves risks. In addition to those risks commonly associated with surgery, the following risks are also associated with use of a neurostimulation system:
- Unpleasant sensations or motor disturbances, including involuntary movement, caused by stimulation at high outputs (If either occurs, turn off stimulation immediately.)
- Undesirable changes in stimulation, which may be related to cellular changes in tissue around the electrodes, changes in electrode position, loose electrical connections, or lead failure
- Stimulation in unwanted places
- Radicular chest wall stimulation
- Lead migration, causing changes in stimulation or reduced pain relief
- Epidural hemorrhage, hematoma, infection, spinal cord compression, or paralysis from placement of a lead in the epidural space
- Cerebrospinal fluid (CSF) leakage
- Paralysis, weakness, clumsiness, numbness, or pain below the level of the implant
- Persistent pain at the electrode site
- Seroma (mass or swelling) at the implant site
- Allergic or rejection response to device materials