Electrode Dilator for Precise Nerve Location in Active Muscle
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Solution Overview
Problem
Current nerve mapping methods during surgical procedures, such as retroperitoneal endoscopic surgery, fail to accurately locate nerves, leading to potential trauma due to the inability to determine the precise location of nerve activation and requiring muscle relaxation to record responses, which complicates instrument advancement through active muscles.
Innovation Solution
A dilator with electrodes that communicate current to the tissue to evoke muscle action potentials, allowing for precise nerve location determination through titrated current applications and feedback mechanisms, enabling the user to steer clear of nerves during surgical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional nerve mapping methods are used, then nerve proximity can be detected, but the precise location of the nerve cannot be determined
Solution Approach 1:
The device segments the nerve monitoring function into multiple components: a dilator with multiple electrodes along its shaft, a stimulation source, and a response detection system. By dividing the monitoring function across multiple spatially distributed electrodes, the system can precisely locate nerves along the dilator's length rather than only detecting their presence.
Solution Approach 2:
The system provides real-time feedback to the surgeon through visual or auditory signals when an electrode detects nerve activity. This feedback mechanism allows the surgeon to immediately identify the precise location of the nerve along the dilator shaft and adjust instrumentation accordingly, transforming vague nerve proximity detection into precise location identification.
2Reliability
If muscle action potentials are recorded to detect nerves, then nerve proximity can be identified, but the muscle must be relaxed which complicates instrument advancement
Solution Approach 1:
The system applies partial action by using low-level stimulation currents that are sufficient to elicit detectable muscle action potentials from nerves without requiring complete muscle relaxation. The electrodes are positioned to detect nerve-induced potentials even when the muscle remains partially active, allowing instrument advancement while maintaining nerve detection reliability.
Solution Approach 2:
The dilator with its embedded electrodes serves as an intermediary between the stimulation source and the muscle/nerve tissue. This intermediary structure allows the system to detect nerve activity through muscle action potentials without requiring the entire muscle mass to be relaxed, as the localized electrode-tissue interface can detect nerve-induced potentials even in partially active muscle.
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
The solution provides accurate nerve location identification, reducing the risk of nerve trauma by allowing precise navigation away from nerves, even in active muscles, thereby enhancing surgical safety and efficiency.
Implementation Method 1
a dilator with electrodes that communicate current to the tissue to evoke muscle action potentials
Data Source
AI summary
One embodiment includes a method for monitoring nerve tissue which includes inserting a dilator into muscle, the dilator including first and second electrodes at the distal tip. While the dilator is in muscle, a system may communicate (a) a first series of unequal current amplitude applications (e.g., a series including 0.5, 7, 3, 5 mA applications) to the first electrode to produce at least a first evoked potential (e.g., a MAP or NAP), and (b) a second series of unequal current amplitude applications to the second electrode to produce at least a second evoked potential. The method further includes sensing the first and second evoked potentials and determining a relative location of a nerve based on the sensing of at least one of the first and second evoked potentials.