EP-4218914-B1 - SYSTEMS FOR NERVE CONDUCTION BLOCK

Inventors

• WU, KENNETH
• ACKERMANN, DOUGLAS MICHAEL
• HARDINGER, Aaron

Dates

Publication Date

20260506

Application Date

20190220

Claims (5)

1. A direct current electrode system comprising: a direct current generator; an electrode lead comprising a working electrode and a counter electrode; and a controller configured to deliver a short circuit current input across the electrode lead of about or less than 100 microamps for less than about 200 microseconds and to: (i) measure a driving voltage across the electrodes, (ii) compare the driving voltage across the electrodes to predetermined threshold values, measure a body impedance, determine a voltage drop across the lead from the body impedance measurement, and (iii) adjust the driving voltage to maintain the voltage drop across the lead within a predetermined voltage range.
2. The system of claim 1, wherein the predetermined voltage range is below the electrolysis potential of water.
3. The system of claim 1, wherein the controller is configured to adjust the amplitude of direct current delivered.
4. The system of claim 1, wherein the direct current comprises cathodic direct current cycled with anodic direct current.
5. The system of claim 1, wherein the direct current comprises a frequency of less than about 1 Hz.

Description

FIELD This application relates to facilitating block of biological signals through nerve tissue. BACKGROUND The gate control theory of pain was developed in the 1960s and led to the advent of stimulation-based pain management therapies to reduce pain inputs from reaching the brain by selectively stimulating non-nociceptive fibers (non-pain transmitting fibers) in the spinal cord to inhibit transmission of pain stimuli to the brain (See Mendell, Constructing and Deconstructing the Gate Theory of Pain, Pain, 2014 Feb 155(2): 210-216). Current stimulation systems for spinal cord stimulation (SCS), which act on this gate control theory to indirectly reduce pain, typically have relied on stimulation signals in the <100 Hz frequency range, and recently in the kHz frequency range. Stimulation of the dorsal root ganglia, DRG, in a similar frequency range has also been employed to reduce segmental pain through the same mechanism. However, technologies based on this premise are not perfect as pain transmission inhibition is not complete and side effects such as paresthesia can be uncomfortable for patients. Therefore, it is desirable to have systems and methods of treating pain which directly block pain fibers from transmitting pain signals, rather than indirectly reducing pain signals through gate-theory activation of non-nociceptive fibers. Furthermore, block of neural tissue or neural activity has been implicated in not only affecting pain but also in the management of movement disorders, psychiatric disorders, cardiovascular health, as well as management of disease states such as diabetes. WO 2017/044542 relates to systems and methods for transcutaneous application of direct current to alter nerve conduction. WO 2017/ 062272 A1 relates to systems and methods to deliver the DC nerve conduction block safely using the high-charge capacity electrode. US 4,917,093 relates to biological tissue stimulators utilizing a constant current output battery-powered since connection to a household power supply would greatly limit the geographical range of operation. US 2006/0265027 A1 relates to pulse generators for electrical stimulation of tissue. SUMMARY The present invention is defined by the appended claims and relates to a direct current electrode system. Aspects, embodiments, examples and methods described hereinafter are only of exemplary nature and presented for better understanding the present invention which is defined by the appended claims. The present disclosure also relates to an exemplary, non-claimed method for more safely monitoring a direct current electrode system. The method can include delivering direct current via an electrode lead to a target tissue of a patient. The method can include measuring the driving voltage across the electrode. The method can include comparing the driving voltage across the electrode to predetermined threshold range values. The method can include measuring the body impedance. The method can include determining a voltage drop across the lead from the body impedance measurement. The method can include adjusting the driving voltage to maintain the voltage drop across the lead within a predetermined voltage range. In some embodiments, measuring the body impedance can include delivering a short circuit current input across the electrode lead. In some embodiments, the short circuit current input can be about or less than about 100 microamps. In some embodiments, the short circuit current input is delivered for less than about 200 microseconds. In some embodiments, the predetermined voltage range is below the electrolysis potential of water. In some embodiments, adjusting the driving voltage can include adjusting the amplitude of direct current delivered. In some embodiments, the direct current can include cathodic direct current cycled with anodic direct current. In some embodiments, the direct current can include a frequency of less than about 1 Hz. An exemplary system for direct current nerve block can include a direct current generator. The system can include a working electrode and a counter electrode. The system can include a controller that can cyclically apply direct current of a first polarity over a first duration and direct current of a second polarity opposite the first polarity over a second duration. The controller can receive measurements of the peak voltage of the first polarity over the first duration and measurements of the peak voltage of the second polarity over the second duration. The controller can adjust the direct current by analyzing the peak voltages over the first duration and the second duration. The controller can increase the current magnitude by a pre-determined amount up to a current limit if the measured peak voltage over the first duration and the second duration is below an absolute threshold limit. The controller can decrease the current magnitude by an amount if the measured peak voltage over the first duration or the second duration is above an abs