Sacral Nerve Stimulation via Chronaxie-Optimized Pulse Width

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Solution Overview

Problem

Current medical devices for urinary and fecal incontinence management using sacral nerve stimulation often require high energy consumption and may not effectively inhibit bladder or bowel contractions without evoking motor responses, leading to inefficiencies and potential discomfort.

Innovation Solution

The use of electrical stimulation therapy with pulse widths determined by the chronaxie of threshold motor responses, delivering stimulation at or near the identified chronaxie to inhibit bladder or bowel contractions without evoking motor responses, thereby reducing energy consumption and improving therapeutic efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If electrical stimulation therapy is delivered with conventional pulse widths to inhibit bladder or bowel contractions, then therapeutic effect is achieved, but energy consumption is high

Engineering Contradiction:

Improveenergy consumptionVSAvoidtherapeutic efficacy

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent changes the pulse width parameter of electrical stimulation to match the chronaxie of the sacral nerve (typically 20-50 microseconds), which is significantly shorter than conventional pulse widths. This parameter optimization allows achieving the same therapeutic effect of inhibiting bladder or bowel contractions while consuming less energy, as shorter pulses require less charge delivery to reach the excitation threshold of nerve fibers

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If electrical stimulation is delivered with higher amplitude to ensure therapeutic effect, then bladder or bowel contraction inhibition is achieved, but motor responses are evoked causing patient discomfort

Engineering Contradiction:

Improvepatient discomfortVSAvoidcontraction inhibition efficacy

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent employs dynamic adjustment of stimulation parameters by first determining the chronaxie of the individual patient's sacral nerve, then using this information to optimize the pulse width and amplitude combination. This dynamic approach allows delivering stimulation at lower amplitudes that inhibit contractions without reaching the threshold for evoking motor responses, thereby reducing patient discomfort while maintaining therapeutic efficacy

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses feedback from chronaxie determination procedures to adjust subsequent stimulation parameters. By measuring the nerve's response characteristics during programming or adjustment sessions, the system learns the optimal pulse width and amplitude settings for that specific patient, enabling personalized therapy delivery that avoids motor response evocation while ensuring effective contraction inhibition

Inventive Principle:

Principle #23Feedback

3Duration of action of stationary object

If conventional electrical stimulation parameters are used, then treatment is provided, but device battery life is limited due to high power consumption

Engineering Contradiction:

Improvedevice longevityVSAvoidpower consumption

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the pulse width parameter to match the chronaxie of the sacral nerve (20-50 microseconds), which minimizes the energy required per stimulation pulse. Since power consumption in electrical stimulation is directly related to pulse width and amplitude squared, this parameter optimization significantly reduces overall power consumption, thereby extending battery life and device longevity without compromising therapeutic effect

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for therapeutically effective stimulation with reduced energy consumption and increased selectivity of nerve fibers, potentially reducing patient discomfort and extending device longevity.

Implementation Method 1

determining a chronaxie of evoked threshold motor responses from electrical stimulation delivered to a sacral nerve of a patient

Methodology Applied

Scientific EffectElectrical stimulation: Electrical Impedance Tomography

Implementation Method 2

delivering, based on the determined chronaxie, electrical stimulation therapy configured to treat a patient condition to the sacral nerve having a pulse width at or near the identified chronaxie, wherein the delivered electrical stimulation is configured to inhibit contraction of at least one a bladder or bowel of the patient

Methodology Applied

Scientific EffectChronaxie-based pulse width modulation:

Data Source

PatentUS11672978B2Sacral nerve stimulation

Publication Date: 2023.06.13 MEDTRONIC INC

AI summary

In some examples, a method including determining a chronaxie of evoked threshold motor responses from electrical stimulation delivered to a sacral nerve of a patient; and delivering, based on the determined chronaxie, electrical stimulation therapy, configured to treat a patient condition, to the sacral nerve having a pulse width at or near the identified chronaxie, wherein the delivered electrical stimulation is configured to inhibit contraction of at least one a bladder or bowel of the patient.