Implantable stimulation devices are devices that generate and deliver electrical stimuli to body nerves and tissues for the therapy of various biological disorders, such as pacemakers to treat cardiac arrhythmia, defibrillators to treat cardiac fibrillation, cochlear stimulators to treat deafness, retinal stimulators to treat blindness, muscle stimulators to produce coordinated limb movement, spinal cord stimulators to treat chronic pain, cortical and deep brain stimulators to treat motor and psychological disorders, and other neural stimulators to treat urinary incontinence, sleep apnea, shoulder sublaxation, etc. The present invention may find applicability in all such applications, although the description that follows will generally focus on the use of the invention within a Spinal Cord Stimulation (SCS) system, such as that disclosed in U.S. Pat. No. 6,516,227.
Spinal cord stimulation is a well-accepted clinical method for reducing pain in certain populations of patients. As shown in FIG. 1, a SCS system typically includes an Implantable Pulse Generator (IPG) 100, which includes a biocompatible case 30 formed of titanium, for example. The case 30 typically holds the circuitry and power source or battery necessary for the IPG 100 to function, although IPGs can also be powered via external RF energy and without a battery. The IPG 100 is coupled to electrodes 106 via one or more electrode leads (two such leads 102 and 104 are shown), such that the electrodes 106 form an electrode array 110. The electrodes 106 are carried on a flexible body 108, which also houses the individual signal wires 112 and 114 coupled to each electrode. In the illustrated embodiment, there are eight electrodes on lead 102, labeled E1-E8, and eight electrodes on lead 104, labeled E9-E16, although the number of leads and electrodes is application specific and therefore can vary.
FIG. 2 shows portions of an IPG system in cross section, including the IPG 100 and a remote controller 12. The IPG 100 typically includes an electronic substrate assembly 14 including a printed circuit board (PCB) 16, along with various electronic components 20, such as microprocessors, integrated circuits, and capacitors mounted to the PCB 16. Two coils are generally present in the IPG 100: a telemetry coil 13 used to transmit/receive data to/from the remote controller 12, and a charging coil 18 for charging or recharging the IPG's power source or battery 26 using an external charger (not shown). The telemetry coil 13 can be mounted within the header connector 36 as shown.
A remote controller 12 is used to communicate with and control a patient's IPG 100. Such external control is beneficial, because a patient's stimulation needs may change throughout the day. For example, different therapy settings may be required for when the patient is sleeping, standing, sitting, or driving. Some settings are saved as “presets” or “programs” and can be selected by the patient using the remote controller 12. As well as being useable to select a particular therapy program, the remote controller 12 can be used to increase or decrease stimulation strength, select different areas of the body or electrodes to be stimulated, and to shut off and turn on stimulation. In addition, the remote controller 12 can act as a receiver of data from the IPG 100, receiving various data reporting on the IPG 100's status. Remote controller 12 is hand-held and portable.
The communication of data from the remote controller 12 to the IPG 100 occurs via magnetic inductive coupling. When data is to be sent from the remote controller 12 to the IPG 100, coil 17 is energized with an alternating current (AC). Such energizing of the coil 17 to transfer data can occur using a Frequency Shift Keying (FSK) protocol for example, such as disclosed in U.S. Patent Publication 2009/0024179 (pending). Energizing the coil 17 induces an electromagnetic field, which in turn induces a current in the IPG's telemetry coil 13, which current can then be demodulated to recover the original data.
As is well known, inductive transmission of data or power occurs transcutaneously, i.e., through the patient's tissue 25, making it particular useful in a medical implantable device system.
Clinicians treating patients with implantable medical devices that they have not implanted or are not familiar with may have doubts about the use of various therapeutic or diagnostic techniques on such patients. For example, the clinician or the patient may have concerns related to the compatibility of certain therapeutic or diagnostic techniques with the patient's implant, such as use of computerized tomography (CT) scans, magnetic resonance imaging (MRI), diathermy, transcutaneous electrical nerve stimulation (TENS), etc. Patients may also be worried about the compatibility with other non-medical related activities, such as running, swimming, contact sports, taking an airplane, going through X-ray checkpoints, etc., and to what extent such activities are contraindicated by the patient's implant.
Usually such concerns take time to be addressed since the patient or clinician may need to contact the manufacturer of the implant system or its service representative regarding the proposed therapeutic or diagnostic technique or desired activity and relevant contraindications arising from the implanted medical device. While patient manuals or clinician manuals provided with the implant system may contain the desired information, patients and clinicians rarely have the information available when needed.