Spinal cord stimulator

Abstract

To provide a new system and method for spinal cord stimulation.SOLUTION: A spinal cord stimulator may comprise: a pulse generator comprising electronic circuitry configured to generate output current; at least one lead in communication with the generator and configured to extend into the epidural space of a patient's spinal column; at least one electrode contact located proximate to a distal end of the at least one lead and configured to provide electric stimulation to a portion of a patient's spinal cord; and at least one sensor located along the at least one lead configured to determine a distance between the at least one lead and a surface of the patient's spinal cord; where the generator receives the determined distance, and where the generator is configured to adjust the stimulation provided by the at least one electrode contact based on the determined distance.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to medical devices. More particularly, the present disclosure relates to improved methods and devices for electrical therapeutic stimulation using spinal cord stimulation devices, cardiac pacemakers, and the like.

Background Art

[0002] For over 50 years, electrical stimulation of the posterior column of the spinal cord has been used as a treatment for chronic pain. Generally, therapeutic interventions using the central, peripheral, or autonomic nervous system for the purpose of a therapeutic effect by targeted electrical stimulation or pharmacological delivery from an implanted device are referred to as neuromodulation. Spinal cord stimulation (SCS), also known as posterior column spinal stimulation, is one of the most established forms of neuromodulation used in the treatment of neuropathic pain. Neuropathic pain refers to pain caused by nerve tissue and is a maladaptive response to nerve injury in the peripheral or central nervous system. Neuropathic pain may exist independently of any form of tissue damage outside the central nervous system. Examples of conditions that can cause neuropathic pain include diseases (e.g., HIV, herpes, diabetes, cancer, autoimmune disorders), acute trauma (surgery, injury, electric shock), and chronic trauma (repetitive motion disorder, alcohol, chemical toxicity such as chemotherapy or heavy metals).

[0003] SCS is also used in the treatment of chronic severe ischemic limbs, angina, and other visceral pain syndromes, including ischemic pain syndromes such as chronic pancreatitis, chronic painful bladder syndrome, chronic abdominal pain, brachial plexus injury, phantom limb pain, and ischemic limb pain.

[0004] One issue regarding the effectiveness of SCS as a pain management method is the observation that the voltage and current thresholds of SCS vary depending on body position. A significant change in voltage or current requirements has been confirmed when moving from a supine position to a sitting or standing position. Therefore, there is a continuing need to develop an SCS system that can dynamically adapt to changes in posture position. Furthermore, a method is needed to expand the therapeutic effect of SCS to the treatment of somatic pain as well as visceral pain.

Summary of the Invention

[0005] In one embodiment of the present disclosure, a spinal cord stimulation device includes a pulse generator having an electronic circuit configured to generate an output current, at least one lead in communication with the generator and configured to extend into the epidural space of a patient's spinal column, at least one electrode contact disposed proximate to the distal end of the at least one lead and configured to provide electrical stimulation to a portion of the patient's spinal cord, and at least one sensor disposed along the at least one lead and configured to determine the distance between the at least one lead and the surface of the patient's spinal cord. The generator may receive the determined distance, and the generator may be configured to adjust the stimulation provided by the at least one electrode contact based on the determined distance.

[0006] In another embodiment of the present disclosure, a method of electrotherapeutic treatment may include placing one or more leads into the epidural space of a patient's spinal column, placing one or more leads near a target stimulation region of the patient's spinal cord, stimulating at least one electrode contact disposed proximate to the distal end of the one or more leads by generating an output current with a generator in communication with the one or more leads, determining, by a sensor, the distance between the one or more leads and the surface of the patient's spinal cord, and adjusting the stimulation of the at least one electrode contact based on the determined distance.

[0007] In yet another embodiment of the present disclosure, a method of electrotherapeutic therapy includes placing one or more leads within the epidural space of a patient's spine, placing one or more leads near a target stimulation region of the patient's spinal cord, stimulating a first electrode contact disposed proximate to the distal end of the one or more leads by generating a first output current with a generator in communication with the one or more leads, stimulating a second electrode contact disposed proximate to the distal end of the one or more leads by generating a second output current with a generator in communication with the one or more leads, creating a zone of induced current that causes stimulation based on stimulating the first electrode contact and the second electrode contact, determining, by a sensor, a distance between the one or more leads and the surface of the patient's spinal cord, and adjusting the position of the zone of induced current that causes stimulation based on the determined distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

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DETAILED DESCRIPTION OF THE INVENTION

[0009] Disclosed herein is an electrotherapeutic physical therapy comprising a spinal cord stimulation (SCS) system that changes one or more characteristics of the electrical output of the SCS system in response to changes in the postural characteristics of a subject in which the SCS system is embedded. In one aspect, the SCS system can be independently programmed to deliver a current for a selected duration at a selected time to address postural changes of the subject being treated and to address visceral pain or both, and comprises a plurality of electrodes. Hereinafter, such a system is referred to as a phase postural change spinal cord stimulation device and is called PACS.

[0010] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the claimed material belongs. The following terms are defined.

[0011] As used herein, the term "communicating" refers to a stimulation lead being adjacent to, generally proximate to, proximate to, directly adjacent to, or directly over a given stimulation site. Thus, when a stimulation modulates neural activity, it should be understood that the lead is "communicating" with a given site. The given site can be selected from the group consisting of the spinal cord and the dorsal columns of the spinal cord, which may include spinal cord regions corresponding to cervical segments C1 - C8, thoracic segments T1 - T12, or lumbar segments L1 and L2. Further, it should be understood that the spinal cord typically terminates at or just above the second lumbar vertebra L2. However, in a particular subject, the spinal cord may terminate anterior or posterior to the L2 vertebral segment, and the claimed material is intended for use along the entire length of the spinal cord regardless of length.

[0012] As used herein, "spinal cord", "spinal nerve tissue associated with a vertebral segment", "nerve tissue associated with a vertebral segment", or "spinal cord associated with a vertebral segment or level" includes any spinal nerve tissue associated with a vertebral level or segment. It should be understood that the spinal cord and associated tissues are related to the cervical, thoracic, and lumbar vertebrae. As used herein, C1 refers to cervical segment 1, C2 refers to cervical segment 2, and so on. T1 refers to thoracic segment 1, T2 refers to thoracic segment 2, and so on. Unless otherwise specified, L1 refers to lumbar segment 1, L2 refers to lumbar segment 2, and so on. In certain cases, a spinal nerve root exits from the bony spine at a vertebral level different from the vertebral segment with which the nerve root is associated. For example, the T11 nerve root exits from the spinal cord myelum in a region located behind vertebral bodies T8 - T9, but exits from the bony spine between T11 and T12.

[0013] As used herein, the use of the term "posterior column of the spinal cord" refers to a conduction pathway of the spinal cord located dorsally within the posterior horn of the spinal cord and containing afferent somatosensory neurons. The posterior column of the spinal cord is also known as the posterior funiculus of the spinal cord. The deeper part of the posterior horn contains visceral afferent neurons.

[0014] As used herein, "epidural space" or "spinal epidural space" refers to the region in the interval between the pia mater or outer layer of the intrathecal space and the bony wall of the spinal canal.

[0015] As used herein, the term "neuronal" refers to a neuron, which is the morphological and functional unit of the brain, spinal column, and peripheral nerves.

[0016] As used herein, the term "somatosensory system" refers to a division of the peripheral nervous system that mainly includes afferent somatosensory neurons and afferent visceral sensory neurons that receive sensory information from the skin and deep tissues, including 12 cranial nerves and 21 spinal nerves.

[0017] As used herein, the terms "stimulate" or "stimulation" refer to electrical, chemical, thermal and / or magnetic stimulation that modulates a given site of the nervous system.

[0018] As used herein, the terms "treat" and "treatment" refer to modulating a specific region of the spinal cord using electrical stimulation such that the subject has an improvement in a disease, e.g., an improvement in pain without sensory abnormalities. Beneficial or desirable clinical outcomes include, but are not limited to, alleviation of symptoms, whether detectable or undetectable, reduction in the degree of the disease, stabilization of the disease state (i.e., does not worsen), delay in the progression of the disease, improvement or alleviation of the disease state, and remission (partial or complete). It is to be understood that treatment can improve the disease state but may not result in a complete cure of the disease.

[0019] As used herein, the term "pain" refers to an unpleasant sensation. For example, a subject experiences discomfort, agony or suffering. Those skilled in the art know that conditions with various pains can be classified either broadly as opposing or otherwise according to useful categories. Examples of opposing categories include nociceptive pain versus non-nociceptive pain and acute pain versus chronic pain. Examples of other common categories of pain used by those skilled in the art include neuropathic pain and phantom pain.

[0020] As used herein, the term "acute pain" refers to pain that is either inherently transient or persists for less than one month. Acute pain is typically associated with an immediate noxious process such as soft tissue injury, infection or inflammation, and serves the purpose of alerting the animal to that noxious condition, thereby allowing subsequent treatment and prevention of injury.

[0021] As used herein, the term "chronic pain" refers to pain that persists for longer than one month, persists beyond the resolution of acute tissue injury, recurs, or is predicted to continue or progress, and is associated with tissue injury and / or chronic diseases. Examples of chronic diseases that are predicted to continue or progress may include cancer, arthritis, inflammatory diseases, chronic wounds, cardiovascular accidents, spinal cord injuries, central nervous system disorders, or recovery from surgery.

[0022] As used herein, the term "neuropathy" refers to any condition that adversely affects the normal function of the nervous system. Neuropathy can occur anywhere in the central or peripheral nervous system, but neuropathic pain occurs in only some cases.

[0023] As used herein, the term "phantom pain" refers to a condition in which a patient feels pain in a part of the body that is known to no longer physically exist due to amputation or is completely numb due to destruction of the entire peripheral nerve.

[0024] In one embodiment of the present disclosure, an electrode array or "lead" has a piezoelectric sensor or an ultrasonic sensor incorporated on a surface facing the back of the spinal cord, and emits ultrasonic pulses at intervals activated by certain intervals or conditions to identify the distance from the lead to the spinal cord. The directly measured distance information is utilized to control the current amount and the lead configuration of current application for optimal stimulation of the patient's spinal cord.

[0025] In another embodiment of the present disclosure, a unique and separate supra-physiological high-frequency signal or current is simultaneously applied to various leads to create a non-linear zone of induced current deeper within the spinal cord parenchyma than can be comfortably tolerated in other ways, by a current curve electric field generated by a simple anode-cathode single frequency and the in-phase current used in the current design.

[0026] In yet another embodiment of the present disclosure, the insulating material for the lead is an optical fiber material that enables the stimulation device generator to transmit optical information to the lead array to control the conductivity within the lead, change the lead configuration, or enable other special features of the distal lead array such as additional capacitance, or the lead itself is composed of an optical fiber material that can send back optical information such as the sensing of a strong magnetic field to the stimulation device generator that can shift the generator to a safe mode to protect the patient from damage.

[0027] In yet another embodiment, the use of conductive carbon fibers without magnetic moment renders the lead system insensitive to magnetic fields without the need for expensive shielding.

[0028] In another embodiment, an intraoperative programming display system combines information from previous MRIs or other imaging of the patient's spine, intraoperative fluoroscopy, and the distance detected by ultrasound from the lead to the spinal cord to display a modeled electric field generated during lead placement to optimize information transfer within the implantation procedure.

[0029] Referring to FIG. 1, in its simplest form, spinal cord stimulation comprises a stimulation electrode 110 implanted in the epidural space 120, an electrical pulse generator 102 implanted in the lower abdomen or gluteal region, a wire or lead 104 connecting the electrode 110 to the generator 102, and optionally, a generator remote control and a generator charger. FIG. 1 shows a cross-sectional mid-sagittal view of the spinal cord and a general stimulation system 100 that can be used for phase postural change spinal cord stimulation (PACS) and other stimulation applications.

[0030] Such a system 100 may typically include an implantable pulse generator (IPG) 102 (which may also be known as a power source), a linear or percutaneous stimulation lead 104, and an electrode array 110 that is part of the stimulation lead 104. The electrode array 110 may include a plurality of electrode contacts 112. In some embodiments, the electrode contacts 112 can be disposed in an in-line electrode array 110 at the distal end of the lead 104. In some embodiments further described herein, other electrode array configurations can also be used. During operation, the IPG 102 can be configured to generate stimulation current pulses that are applied to selected electrode contacts 112 within the electrode array 110. In some embodiments, the electrode contacts 112 may be individually and selectively controlled to apply the stimulation current pulses. The stimulation lead 104 conducts the stimulation current from the IPG 102 to the electrode contacts 112 of the electrode array 110.

[0031] The IPG 102 may include a header piece or connector block 105 having at least one opening for receiving the connector end of the lead 104 and / or an extension lead or other lead connector. Optionally, the connector block 105 can have two openings for receiving the connector ends of two stimulation leads and / or extension leads.

[0032] The IPG 102 can include an electrical circuit and be powered by an internal power source that can output current pulses to each stimulation channel through the use of the electrical circuit. Communication with the implanted IPG 102 can be achieved using an external programmer or remote (not shown).

[0033] As shown in FIG. 1, at least a portion of the percutaneous stimulation lead 104, and more specifically the electrode array 110, is implanted in the epidural space 120 of the patient, adjacent to the spinal cord 122. Since there is not enough space near the lead exit point 106 where the electrode lead 104 exits the spine, the IPG 102 may be implanted in the abdomen or on the buttocks.

[0034] The power supply of the IPG102 may be connected to one or more contacts to enable the conduction of electrical impulses to the spinal cord. The spinal cord stimulation device lead 106 may include an external contact electrode 112 on a paddle configured to send impulses to the distal tip, end, or spinal cord. In one aspect, the distal contact electrodes 112 are independently connected to corresponding contact terminals at the proximal end of the lead 104 by separate twisted wires (lead wires) running substantially parallel to each other within the lead 104. The proximal conductive terminals may then be connected to the power supply via a lead extension connector that contacts the proximal lead terminals individually and enables the transmission of electrical signals from the power supply to the distal lead electrodes.

[0035] In one embodiment, the power supply (or IPG) 102 may provide electrical stimulation and allow for selective and independent variation of the characteristics of the power, including amplitude, frequency rate, and pulse width, as well as variation of the polarity of the conductive electrode contacts 112 within one or more leads 104.

[0036] In one embodiment of the present disclosure, the IPG system may include an implantable pulse generator 102 and an external portable charger. The IPG 102 may include a sealed case 140 surrounding an electronic circuit 142 such as a memory circuit housed within the sealed case. The electronic circuit includes a number of independent bidirectional output current sources, each output current source being connected to an electrode node. The electronic circuit 140 may include a number of coupling capacitors, each coupling capacitor being connected to each of the electrode nodes. The IPG 102 may include a header connector 105 attached to the sealed case 140. The header connector 105 has a number of through pins passing therethrough, and each of the number of coupling capacitors is connected to one of the through pins on the sealed side of the case. As described above, the IPG 102 may communicate with an electrode array 110 having a number of electrodes 112 outside the sealed case 140. Each electrode 112 is removably electrically connected to one of the through pins on the unsealed side of the sealed case 140. Each output current source generates an output stimulation current having a selected amplitude and polarity that is directed to the connected electrodes via the respective through pins and coupling capacitors when the output stimulation current source is enabled. As described above, the IPG may include a signal generator capable of sending an ultrasonic compatibility current to an implanted piezoelectric element that measures the distance to the back of the spinal cord, and a circuit element capable of sensing the signal and the time required for the signal to return and measure the distance to the spinal cord.

[0037] In some embodiments, the IPG 102 may include a rechargeable battery 144 that provides operating power to the electronic circuit, secondary coil, and rectifier circuit. The IPG system may also include a battery charger and protection circuit that receives externally generated energy via the secondary coil and rectifier circuit and uses the externally generated energy to charge the rechargeable battery 144. Advantageously, the rectifier circuit may be modulated between a full-wave rectifier circuit and a half-way rectifier circuit, which enables detection of an external portable charger by monitoring the reflected impedance that probes the secondary coil when the IPG battery is fully charged.

[0038] In the embodiment shown in FIG. 1, the stimulation system 100 may include a sensor 130 that physically communicates with a power source and is a physical part of the linear or paddle electrode array 110. The sensor 130 may be configured to identify the position of the spinal cord 122 relative to the electrode array 110 and / or the lead 104. This sensed position and / or orientation may be used to identify the power, polarity, and actuation characteristics of the electrode contacts 112 within the electrode array 110. In FIG. 1, the sensor 130 is shown as being disposed near and / or within the electrode array 110, but in other embodiments, the sensor 130 may be disposed anywhere within the portion of the lead 106 that is within the epidural space 120 of the spinal cord 122.

[0039] Referring to FIG. 2, the lead 106 is in fluid communication with the sensor 130. The sensor 130 may include an ultrasonic sensor configured to generate and / or detect sound waves 132. In some embodiments, the sensor 130 may include a piezoelectric transducer configured to generate ultrasonic waves 132. In some embodiments, the sensor 130 may include a receiver configured to detect ultrasonic waves reflected from the spinal cord 122 toward the sensor 130. As shown in FIG. 2, the sensor 130 may be disposed within the epidural space 120 and may direct sound waves to the back 123 of the spinal cord 122. In the generalized view of FIG. 2, the spinal cord 122 may include a posterior horn 124 and may be surrounded by cerebrospinal fluid 126. In some embodiments, the lead 104 may contact the vertebral arch, a bony structure on each vertebra that provides a roof for the spinal canal and protects the back of the spinal cord.

[0040] The type of PACS100 disclosed herein grasps the postural changes of a subject with an implant device by sensing the distance to the posterior surface 123 of the spinal cord 122. This distance is an important variable in the stimulation programming of current and lead variable control. In particular, the postural changes of a subject having the type of PACS disclosed herein result in a change in the distance to the posterior surface 123 of the spinal cord 122 detected by the ultrasonic sensor 130. The sensor 130 may comprise at least one lead-embedded piezoelectric sensor and may generate an electrical signal for at least one lead configured to adjust the range and area of power supply (or IPG) and / or electrical stimulation. Adjustments may be determined based on the detected spinal displacement to maintain and / or increase pain relief by treatment. By combining the distance information with feedback from the patient, the details of the IPG programming for effectively stimulating each patient are facilitated.

[0041] While not wishing to be limited by theory, sensor 130 may comprise at least one piezoelectric transducer, or a plurality of piezoelectric transducers. Sensor 130 may comprise a piezoelectric element configured to generate an ultrasonic signal and / or a detector element configured to detect an ultrasonic signal. In one embodiment, the ultrasonic sensor 130 of the present disclosure is a distance sensor that can function by emitting a short burst of ultrasonic waves at a suitable frequency from a piezoelectric transducer. In some embodiments, ultrasonic sensor 130 may generate or emit ultrasonic waves in response to a change in the posture of an object that can be detected by a certain type of motion sensor (for example, another part of the IPG and / or PACS may comprise a motion sensor). A small amount of acoustic energy is reflected by an object (i.e., a spinal component) in front of ultrasonic sensor 130 and returned to a detector of sensor 130, which may be a piezoelectric transducer. In one embodiment, ultrasonic sensor 130 further comprises a receiver amplifier that transmits these reflected signals (echoes) to a microcontroller, and this receiver amplifier uses the speed of sound waves in the interstitial space and cerebrospinal fluid to time these reflected signals to identify how far away the object is. The calculated range is then converted and used to adjust the pattern and / or amplitude of the electrical stimulation to relieve pain. In one embodiment of the present disclosure, the information obtained from the calculated range from ultrasonic sensor 130 may be used to adjust the output and / or configuration of the electrical stimulation in response to a change in posture. For example, using the information received from ultrasonic sensor 130, physical therapy for pain relief that may involve stimulation using the distal ends of one or more leads may be determined while excluding stimulation from any different single or multiple leads.

[0042] As an example, referring to FIG. 3, due to a change in posture, the spinal cord 122 may move within the cerebrospinal fluid 126 relative to the lead 106 and thus the sensor 130. This change can be detected by determining the distance between the sensor 130 and the posterior surface 123 of the spinal cord 122 (which is a greater distance in FIG. 3 than the distance shown in FIG. 2). The movement of the spinal cord 122 and thus the posterior horn 124 may affect the stimulation of the posterior horn by the lead 106 (i.e., the electrode contacts described in FIG. 1).

[0043] In one aspect, the power supply (or IPG) 102 may comprise a programmable current source that can be used to control the amplitude, phase duration, and phase relationship of the one or more leads 104 (and thus the electrode array 110 and the electrode contacts 112). For example, the programmable current source used in the present disclosure can use pulse amplitude control, pulse timing control, and pulse duration control to individually set the current, timing, and pulse duration parameters of the one or more leads 104. Thus, each of the electrode contacts 112 can deliver the same intensity pulse over the same time and for the same duration as needed. Alternatively, the pulse intensity, phase, and duration may be adjusted independently of each other for each electrode contact 112 to generate the phase relationship of the electrode contacts 112.

[0044] In some embodiments, FIG. 2 may show the spinal cord when the patient is lying supine, and the surgeon and / or technician may cycle through a plurality of electrode configurations while the spinal cord is in the position shown in FIG. 2 during the placement of the system 100 to establish a target electric field. As part of the process of establishing the target electric field, the sensor 130 may be activated to determine the current distance between the lead 104 and the posterior surface of the spinal cord 123, and the target electric field may be associated with this determined distance.

[0045] Similarly, FIG. 3 can show the spinal cord when the patient is lying prone. The surgeon and / or technician may cycle through a plurality of electrode configurations to establish a target electric field while the spinal cord is in the position shown in FIG. 3 during placement of the system 100. As part of the process of establishing the target electric field, the sensor 130 may be activated to identify the current distance between the lead 104 and the posterior of the spinal cord 123, and the target electric field may be associated with this identified distance, which distance and target electric field may be different from those identified as shown in FIG. 2.

[0046] In some embodiments, a first target electric field may be established when the patient is in a first position (e.g., FIG. 2), and a second target electric field may be established when the patient is in a second position (e.g., FIG. 3).

[0047] Referring to FIG. 4, in such embodiments, the phase of the electrical signal generated by the electrode contacts 112 may be configured to generate a phase signal that penetrates relatively deeply into the posterior horn of the spinal cord where visceral sensory processing occurs, without the discomfort associated with excessive stimulation of the relatively superficial posterior horn where somatic sensation occurs. Treatment of visceral pain can be achieved through the use of supra-physiological frequencies that do not significantly stimulate the superficial posterior horn but that create one or more zones of induced current in the relatively deeper posterior horn via phase signal generation, and / or through the use of beat frequencies to create these relatively deeper signal convergence zones within the physiological stimulation frequency range.

[0048] The relatively superficial (or near-surface) portion of the posterior horn, the sensory portion of the spinal cord, senses the arms and legs and the abdominal and chest walls. Slightly deeper within the posterior horn are nerves that sense the viscera. The ability to stimulate the relatively deeper posterior horn without overly stimulating the relatively superficial posterior horn (which is painful) enables the treatment of visceral pain such as pancreatitis and / or types of cancer pain. The current system uses a waveform 402 that does not have contrasting, interfering, different-phase, or different-frequency waveforms in order to utilize the generation of non-linear electric fields.

[0049] Referring to FIG. 5, at frequencies that are too high to stimulate the dorsal horn cells, a zone of induced current of low-frequency current that physiologically stimulates relatively deep tissue may be induced using adjustments of frequency, amplitude, current, phase, and additional beat frequencies. The zone of induced current can be formed at an off-axis distance 510 by adjusting the stimulation of the first electrode contact 501 and the second electrode contact 502 (which may be similar to the electrode contact 112 described above). In one embodiment, the off-axis distance 510 and the frequency attributes determine the induced current zone.

[0050] FIG. 6A shows an example of the paraxial case, where no current is induced because waveforms 601 and 602 meet at the same voltage (at point 604). The waveforms 601 and 602 themselves are at frequencies too high to stimulate the surface dorsal horn neurons. In the embodiment shown in FIG. 6A where the waveform voltages meet near the axis of the lead, the voltages are the same and no current is induced.

[0051] Referring to FIG. 6B, by introducing a phase-adjusted frequency difference (“beat” frequency), the phase of the off-axis waveforms can be affected such that they are different, which means that there are different voltages, or induced current, at the location (point 604) where waveforms 601 and 602 meet. The off-axis waveforms 601 and 602 can stimulate relatively deep structures without overly stimulating relatively shallow neural structures, and this technique is highly dependent on information about the distance to the target stimulation zone. The difference in voltage between these two waveforms 601 and 602 means that current is induced at this location in the spinal cord. Similar effects occur by using the beat frequency, differential phase adjustment of different leads, and high-frequency amplitude modulation, creating a zone of induced current having a magnetic flux of approximately the same magnitude as the current-curve stimulation field.

[0052] In one embodiment, to achieve relief of both conditions in patients suffering from somatic and visceral pain, both curve mode and non-curve mode stimulations can be used simultaneously or switched at a high speed such that they appear physiologically simultaneously. In some embodiments, the same system can use direct current stimulation from at least one electrode contact and generate a zone of induced current for stimulating a portion of the patient's spinal cord using at least two electrode contacts. For example, when measured by a sensor, if the spinal cord is located at a first distance from the lead (as described above), direct current stimulation from one or more electrode contacts may be appropriate for stimulating the target region of the spinal cord. Next, when the spinal cord moves to a second distance from the lead (with the patient's movement) as measured by the sensor, stimulation may be achieved by generating a zone of induced current using two electrode contacts (as described above), where one of the two contacts may be the same as the contact that generated the direct current stimulation. Alternatively, the electrode contacts may all be part of an electrode array, and any of several electrode contacts may be used individually or together.

[0053] To treat certain types of pain, different electric field configurations may be required. As an example, to treat angina, the thoracic spinal cord at a relatively high position and the cervical spinal cord at a relatively low position may be stimulated. Since the spinal cord itself is shortened and the spinal cord parenchyma does not correspond to the vertebral segments from which each spinal nerve exits, the stimulation typically occurs above the actual vertebral segment associated with the innervation of the target pain site. Similarly, to treat renal colic and / or pancreatitis, the middle to upper portion of the thoracic spinal cord may be stimulated, and to treat the source of pelvic pain, the lower portion of the thoracic spinal cord may be stimulated.

[0054] In one embodiment, the present disclosure includes interference therapy that uses medium to high frequency electric currents that can simultaneously pass through a target tissue (e.g., the spine) such that their paths cross and they literally interfere to produce interference, interaction, induction, or a beat frequency. The exact frequency of the resulting beat frequency can be controlled by the input frequencies. An exemplary and non-limiting example is using a first signal having a frequency of 4000 Hz and an accompanying signal having a frequency of 3900 Hz to result in a beat frequency of 100 Hz transmitted as an amplitude modulated current at an intermediate frequency of 3950 Hz. By the function of treating visceral pain in this way, the need for chronic opioid therapy and the associated risks are reduced, and related tolerance problems are avoided. In one embodiment, the present disclosure enables a phase signal of sufficient intensity to provide electrical stimulation while avoiding discomfort in surface tissues (such as skin or muscle).

[0055] Any lead contacts and conductors disclosed herein may be electrically insulated by a suitable insulating material that is safe even when implanted in the human body. Referring to FIG. 7, in some embodiments, the insulating material 704 surrounding the lead 104 (described above) may have optical communication characteristics such as an optical fiber material. Using a new, highly flexible optical fiber material that can withstand mechanical cycles makes communication between the stimulator generator and the distal lead practical. Using the insulator as an optical fiber communication tool can improve communication between the generator 102 and components at the distal end of the lead 104, such as the electrode array 110. The insulating material 704 can enable communication from the generator to the electrode array, control the configuration of the electrode array, and enhance the functionality of the system. For example, photons can move from the generator 102 to the electrode array 110 (and / or other elements of the lead 104) in the direction indicated by the arrow 702. Other elements such as the lead 104 and the electrode array 110 can also communicate directly with the generator 102. For example, photons can move from the electrode array 110 (and / or other elements of the lead 104) to the generator 102 in the direction indicated by the arrow 710. In one embodiment, the magnetic detection element of the distal lead array 110 can generate an optical signal to the IPG 102 to put the system in a safe mode to protect the patient from magnetically induced currents associated with tissue damage. In another embodiment, the IPG 102 can optically signal the distal lead array 110 to change the lead configuration or enhance the lead function by activating additional capacitive elements or other features.

[0056] In addition, the insulating material 704 can be magnetically insensitive so that communication between the generator 102 and the lead 104 can occur without being affected by a magnetic field. For example, the generator and / or the distal lead wire, and an unexpected magnetic field sensed by the generator can automatically generate an optical signal to put the system in a "safe mode" to prevent induced currents from magnetic field exposure.

[0057] The distal contact electrodes may have a variable contact surface area and a variable spacing between the electrodes. The number of electrodes may similarly vary. The spinal cord stimulation generator system transmits an electric current to the spinal cord via a lead composed of conductive elements. These conductive elements typically include a metal alloy such as a platinum-iridium alloy and are susceptible to induced currents by dynamic magnetic fields such as those generated during procedures such as magnetic resonance imaging (MRI) scans. The current induced by the conductive elements connecting the stimulation device generator to the contacts placed on the spinal cord poses a risk of damaging adjacent tissue and the spinal cord. In one embodiment, the lead utilized in the SCS of the present disclosure is composed of a material that does not generate an induced current in a dynamic magnetic field. Further, the materials suitable for use in the present disclosure may be characterized by withstanding deformation when subjected to repetitive mechanical stress. In one embodiment, one or more leads of the present disclosure are manufactured from and / or include conductive carbon fibers or nanotube conductive carbon fibers that do not have a magnetic moment in their pure form. Without wishing to be bound by theory, the use of a diamagnetic conductive material (e.g., carbon fiber) may significantly reduce the risks and the cost of risk mitigation means for an MRI-compatible or MRI-safe spinal cord stimulation system. The system of the present disclosure provides an electromagnetic compatibility implantable medical device that does not include the function of a device that induces a magnetic field.

[0058] In one embodiment, an SCS of the type disclosed herein is used for the treatment of neuropathic pain. In another embodiment, an SCS of the type disclosed herein is used for the treatment of nociceptive pain. In one embodiment, an SCS of the type disclosed herein is used for the treatment of failed back syndrome.

[0059] In some embodiments, the process of embedding or inserting the PACS as described above may include the use of an intraoperative programming display system. Currently, the stimulation device system is arranged via three-way verbal communication among the surgeon, on-site support personnel (or technicians), and the patient. This trial-and-error approach lacks consideration for a specific magnetic flux through the tissue and simply the current to achieve this magnetic flux.

[0060] Referring to FIG. 8, an integrated programming system with a display 800 may be configured to import images of an individual patient's stimulation target zones (as well as operating room (OR) images) and model the magnetic flux through these zones during the surgeon's programming to coordinate with the responses of the company personnel and the patient. For a system that has already loaded selective preoperative images of the patient's spine and spinal cord in axial, coronal, and sagittal views, real-time OR images during lead placement are imported. The placement is facilitated by a function that visually superimposes the labels of each vertebral level. When the operator adjusts the current level and lead configuration, magnetic field lines color-coded by the current density (magnetic flux) are also displayed. This can be done simultaneously in anterior-posterior projection, coronal, axial, and sagittal views. The display 800 may provide a model to the surgeon during the operation, and this model shows where they are in the spinal cord, how deep they have advanced, and the magnetic field density, and different colors may represent different magnetic field densities or levels of magnetic flux.

[0061] Currently, the lead is placed under fluoroscopy showing only the spinal segment level of the lead. In the embodiments described herein, while the surgeon is placing and adjusting the lead within the patient's spinal cord, the operator or technician may communicate with the patient. The operator may cycle through various electrode configurations, and the display 800 may show various characteristics of the electric field based on the current configuration. The display 800 may include imported images of the patient's anatomical structure as well as real-time lead configuration information. The function of generating this image in the operating room includes the function of sensing the distance to the back of the spinal cord.

[0062] Embodiments of the present disclosure include electrotherapy including an MRI - compatible cardiac pacemaker. In one embodiment, the cardiac pacemaker of the present disclosure may be coupled to the heart by a pair of endocardial leads. The first lead, called the right atrial lead, includes a bipolar electrode pair at its distal end for making electrical contact with the right atrium in a suitable manner. The second lead, called the right ventricular lead, similarly includes a bipolar electrode pair at its distal end for making electrical contact with the right ventricle in a suitable manner. In one embodiment, the cardiac pacemaker lead system may have a single contact at the distal portion of the lead for each atrium or ventricle chamber. In one embodiment, the cardiac pacemaker lead system may have multiple contacts at the distal portion of the lead for each atrium or ventricle chamber. In one embodiment, one or more of the leads of the present disclosure are manufactured from and / or include conductive carbon fibers or nanotube - conductive carbon fibers that, in pure form, do not have a magnetic moment. The cardiac pacemaker may further include, but is not limited to, a hermetic enclosure that allows the cardiac pacemaker to be fully implanted under the patient's skin. The cardiac pacemaker may include, within the enclosure, an atrial sensing amplifier, a ventricular sensing amplifier, an analog - to - digital converter, and a pulse generator, a microprocessor, memory, and a telemetry stage.

[0063] Although various devices and methods have been described herein, exemplary embodiments or aspects can include, but are not limited to, the following.

[0064] In the first embodiment, the spinal cord stimulation device includes a pulse generator having an electronic circuit configured to generate an output current, at least one lead in communication with the generator and configured to extend into the epidural space of the patient's spinal column, at least one electrode contact disposed proximate to the distal end of the at least one lead and configured to provide electrical stimulation to a portion of the patient's spinal cord, and at least one sensor disposed along the at least one lead and configured to determine the distance between the at least one lead and the surface of the patient's spinal cord. The generator receives the determined distance and is configured to adjust the stimulation provided by the at least one electrode contact based on the determined distance.

[0065] The second embodiment can include the spinal cord stimulation device of the first embodiment further comprising an electrode array having a plurality of electrode contacts disposed proximate to the distal end of the at least one lead.

[0066] The third embodiment can include the spinal cord stimulation device of the second embodiment, wherein the electrode array is configured to generate a zone of induced current between a first electrode contact and a second electrode contact, and the zone of induced current is disposed within the patient's spinal cord.

[0067] The fourth embodiment can include the spinal cord stimulation device of the third embodiment, wherein the generator is configured to adjust the stimulation based on the determined distance by adjusting the position of the zone of induced current generated by the electrode array.

[0068] The fifth embodiment can include the spinal cord stimulation device of any one of the first through fourth embodiments, wherein the at least one sensor comprises an ultrasonic sensor.

[0069] The sixth embodiment can include the spinal cord stimulation device of any one of the first through fifth embodiments, wherein the at least one sensor comprises a piezoelectric element configured to generate an ultrasonic signal and a detector element configured to detect the reflected ultrasonic signal.

[0070] The seventh embodiment can include the spinal cord stimulation device of the sixth embodiment, and the reflected ultrasonic signal is reflected from the back of the patient's spinal cord.

[0071] The eighth embodiment can include the spinal cord stimulation device of any one of the first to seventh embodiments, and at least one sensor is configured to periodically detect the distance between at least one lead and the surface of the patient's spinal cord.

[0072] The ninth embodiment can include the spinal cord stimulation device of any one of the first to eighth embodiments, further including an insulating material surrounding at least one lead.

[0073] The tenth embodiment can include the spinal cord stimulation device of any one of the first to ninth embodiments, further including a motion sensor configured to detect movement or motion by the patient, and the generator is configured to activate at least one sensor to identify the distance between at least one lead and the surface of the patient's spinal cord based on the movement detected by the motion sensor.

[0074] In the eleventh embodiment, the method of electrotherapeutic physical therapy includes placing one or more leads into the epidural space of the patient's spine, placing one or more leads near the target stimulation area of the patient's spinal cord, generating an output current by a generator communicating with the one or more leads to stimulate at least one electrode contact disposed proximate to the distal end of the one or more leads, identifying, by a sensor, the distance between the one or more leads and the surface of the patient's spinal cord, and adjusting the stimulation of the at least one electrode contact based on the identified distance.

[0075] The twelfth embodiment can include the method of the eleventh embodiment, further including detecting a change in the position of the patient's spinal cord relative to the one or more leads and activating a sensor for identifying the distance between the one or more leads and the surface of the patient's spinal cord.

[0076] The 13th embodiment can include the method of the 12th embodiment that further includes detecting the patient's movement and activating a sensor for specifying the distance between one or more leads and the back of the patient's spinal cord.

[0077] The 14th embodiment can include the method of any one of the 11th to 13th embodiments, and stimulating at least one electrode contact further includes stimulating a part of the patient's spinal cord by current stimulation from at least one electrode contact.

[0078] The 15th embodiment can include the method of any one of the 11th to 14th embodiments, and adjusting the stimulation of at least one electrode contact includes adjusting the intensity of the current stimulation from at least one electrode contact.

[0079] The 16th embodiment can include the method of any one of the 11th to 15th embodiments, and stimulating at least one electrode contact includes stimulating a first electrode contact, stimulating a second electrode contact, and creating a zone of induced current in the patient's spinal cord based on stimulating the first electrode contact and the second electrode contact.

[0080] The 17th embodiment can include the method of the 16th embodiment, and adjusting the stimulation of at least one electrode contact includes adjusting the stimulation of the first electrode and adjusting the stimulation of the second electrode. By adjusting the stimulation of the first electrode and the stimulation of the second electrode, the position of the zone of induced current created by the stimulation of the first electrode contact and the second electrode contact is changed.

[0081] The 18th embodiment can include the method of any one of the 11th to 17th embodiments. Identifying the distance between one or more leads and the surface of the patient's spinal cord by a sensor includes generating an ultrasonic signal by the sensor, detecting the reflected ultrasonic signal by the sensor, where the ultrasonic signal is reflected by the surface of the patient's spinal cord, and analyzing the detected reflected ultrasonic signal to identify the distance between the sensor and the surface of the spinal cord.

[0082] The 19th embodiment can include the method of any one of the 11th to 18th embodiments. Adjusting the stimulation of at least one electrode contact includes adjusting at least one of the pulse intensity, phase, frequency, and duration of the stimulation.

[0083] In the 20th embodiment, the method of electrotherapeutic physical therapy includes disposing one or more leads into the epidural cavity of the patient's spine, disposing one or more leads near the target stimulation region of the patient's spinal cord, stimulating a first electrode contact disposed proximate to the distal end of the one or more leads by generating a first output current by a generator in communication with the one or more leads, stimulating a second electrode contact disposed proximate to the distal end of the one or more leads by generating a second output current by a generator in communication with the one or more leads, creating a zone of induced current that causes stimulation based on stimulating the first electrode contact and the second electrode contact, identifying the distance between the one or more leads and the surface of the patient's spinal cord by a sensor, and adjusting the position of the zone of induced current of the stimulation based on the identified distance.

Claims

1. 1. A spinal cord stimulation device, comprising: a pulse generator comprising an electronic circuit configured to generate an output current; at least one lead in communication with the generator and configured to extend into the epidural space of the patient's spine; at least one electrode contact disposed proximate a distal end of the at least one lead and configured to provide electrical stimulation to a portion of the patient's spinal cord; and at least one sensor disposed along the at least one lead configured to determine a distance between the at least one lead and a surface of the patient's spinal cord, wherein the generator is configured to receive the determined distance, and the generator is configured to adjust the stimulation provided by the at least one electrode contact based on the determined distance.

2. 10. The spinal cord stimulator of claim 1, further comprising an electrode array comprising a plurality of electrode contacts disposed proximate the distal end of the at least one lead.

3. 3. The spinal cord stimulator of claim 2, wherein the electrode array is configured to generate a zone of induced current between a first electrode contact and a second electrode contact, the zone of induced current being positioned within the patient's spinal column.

4. 4. The spinal cord stimulator of claim 3, wherein the generator is configured to adjust the stimulation based on the determined distance by adjusting a position of the zone of induced current generated by the electrode array.

5. The spinal cord stimulator of claim 1 , wherein the at least one sensor comprises an ultrasonic sensor.

6. 10. The spinal cord stimulator of claim 1, wherein the at least one sensor comprises a piezoelectric element configured to generate an ultrasonic signal and a detector element configured to detect a reflected ultrasonic signal.

7. 7. The spinal cord stimulator of claim 6, wherein the reflected ultrasound signal is reflected from a dorsal surface of the patient's spinal cord.

8. The spinal cord stimulator of claim 1 , wherein the at least one sensor is configured to periodically detect the distance between the at least one lead and the surface of the patient's spinal cord.

9. The spinal cord stimulator of claim 1 , further comprising an insulating material surrounding the at least one lead.

10. 10. The spinal cord stimulation device of claim 1, further comprising a motion sensor configured to detect movement or motion by a patient, and wherein the generator is configured to activate the at least one sensor to determine the distance between the at least one lead and the surface of the patient's spinal cord based on the movement detected by the motion sensor.

11. 1. A method of electrotherapy physical therapy comprising: placing one or more leads in an epidural space of a patient's spine; positioning the one or more leads near a target stimulation area of ​​the patient's spinal cord; stimulating at least one electrode contact disposed proximate a distal end of the one or more leads by generating an output current with a generator in communication with the one or more leads; determining, with a sensor, a distance between the one or more leads and a surface of the patient's spinal cord; and adjusting stimulation of the at least one electrode contact based on the determined distance.

12. 12. The method of claim 11, further comprising: detecting a change in position of the patient's spinal cord relative to the one or more leads; and activating the sensor to determine the distance between the one or more leads and the surface of the patient's spinal cord.

13. 13. The method of claim 12, further comprising detecting patient movement and activating the sensor to determine the distance between the one or more leads and the posterior surface of the patient's spinal cord.

14. 12. The method of claim 11, wherein stimulating at least one electrode contact further comprises stimulating a portion of the patient's spinal cord with electrical current stimulation from the at least one electrode contact.

15. The method of claim 11 , wherein adjusting the stimulation of the at least one electrode contact comprises adjusting an intensity of current stimulation from the at least one electrode contact.

16. Stimulating at least one electrode contact includes: Stimulating a first electrode contact; Stimulating a second electrode contact; and creating a zone of induced current in the patient's spinal cord based on stimulating the first electrode contact and the second electrode contact.

17. 17. The method of claim 16, wherein adjusting the stimulation of the at least one electrode contact comprises adjusting the stimulation of the first electrode and adjusting the stimulation of the second electrode, wherein adjusting the stimulation of the first electrode and adjusting the stimulation of the second electrode alters a position of the zone of induced current produced by the stimulation of the first electrode contact and the second electrode contact.

18. determining the distance between the one or more leads and the surface of the patient's spinal cord with the sensor; generating an ultrasonic signal with the sensor; detecting, by the sensor, a reflected ultrasound signal, wherein the ultrasound signal is reflected by the surface of the patient's spinal cord; and analyzing the detected reflected ultrasound signals to determine a distance between the sensor and the surface of the spinal cord.

19. 12. The method of claim 11, wherein adjusting the stimulation of the at least one electrode contact comprises adjusting at least one of a pulse strength, phase, frequency and duration of the stimulation.

20. 1. A method of electrotherapy physical therapy comprising: placing one or more leads in an epidural space of a patient's spine; positioning the one or more leads near a target stimulation area of ​​the patient's spinal cord; generating a first output current by a generator in communication with the one or more leads to stimulate a first electrode contact disposed proximate a distal end of the one or more leads; generating a second output current by the generator in communication with the one or more leads to stimulate a second electrode contact disposed proximate a distal end of the one or more leads; creating a zone of induced current causing stimulation based on stimulating the first electrode contact and the second electrode contact; determining, with a sensor, a distance between the one or more leads and a surface of the patient's spinal cord; and adjusting a location of the zone of induced current causing stimulation based on the determined distance.

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