Cochlear Electrode with Segmented Stiffness for Trauma Reduction
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Solution Overview
Problem
Cochlear implant electrode arrays face challenges in achieving optimal insertion depth and minimizing trauma to delicate anatomical structures due to variations in cochlea size, shape, and curvature, as well as the need for precise positioning close to the modiolar wall for effective stimulation while avoiding insertion trauma.
Innovation Solution
The electrode array is designed with an apical section that follows the outer lateral wall for atraumatic insertion and an adjustable basal branch that positions close to the inner modiolar wall, utilizing a combination of stiffness, geometry, and magnetic elements to facilitate precise placement and minimize tissue trauma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the electrode array is made stiffer to maintain insertion depth, then the array can be inserted to the desired depth without buckling, but mechanical forces on cochlear structures increase causing trauma
Solution Approach 1:
The electrode array is divided into multiple segments with different stiffness characteristics. The proximal portion has higher stiffness to maintain insertion depth, while the distal portion has lower stiffness to reduce mechanical forces on cochlear structures. This segmentation allows each portion to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the electrode array are assigned different mechanical properties (stiffness values) according to their specific functional requirements. The proximal portion is made stiffer for structural support and depth maintenance, while the distal portion is made more flexible to conform to the cochlear duct and minimize trauma. This local differentiation of quality resolves the contradiction between needing stiffness for depth and flexibility for trauma reduction.
2Force
If the electrode array is made more flexible to reduce trauma, then mechanical forces on cochlear structures are reduced, but the array buckles and cannot reach the desired insertion depth
Solution Approach 1:
The electrode array is segmented into proximal and distal portions with differentiated stiffness properties. The proximal portion maintains sufficient stiffness to prevent buckling during insertion and achieve target depth, while the distal portion is designed with lower stiffness to flex and conform to the cochlear duct geometry, reducing mechanical trauma to surrounding structures.
Solution Approach 2:
The electrode array exhibits local quality variations along its length, with the proximal portion having higher stiffness for structural integrity and depth achievement, and the distal portion having lower stiffness for trauma reduction. This spatial differentiation of mechanical properties allows the array to simultaneously achieve insertion depth and minimize mechanical forces on cochlear structures.
3Reliability
If the electrode array is positioned close to the modiolar wall for effective stimulation, then stimulation efficacy is improved, but insertion trauma increases due to the confined space
Solution Approach 1:
The electrode array is segmented with the distal portion designed to navigate through the cochlear duct and position close to the modiolar wall for optimal stimulation. This distal segment has reduced stiffness to allow it to flex and conform to the tight space near the modiolar wall without causing excessive trauma during insertion, while the proximal segment maintains structural support.
Solution Approach 2:
The electrode array has locally differentiated mechanical properties where the distal portion near the modiolar wall has lower stiffness to reduce insertion trauma in the confined space, while maintaining positioning capability for effective stimulation. The proximal portion has higher stiffness for structural support, creating a local quality gradient that resolves the contradiction between stimulation efficacy and trauma reduction.
4Object-affected harmful factors
If the electrode array follows the outer lateral wall for atraumatic insertion, then insertion trauma is minimized, but positioning precision near the modiolar wall is reduced
Solution Approach 1:
The electrode array is segmented into proximal and distal portions with different stiffness characteristics. The proximal portion follows the outer lateral wall for atraumatic insertion, while the distal portion is designed to flex and position close to the modiolar wall for precise stimulation. This segmentation allows the array to sequentially achieve both atraumatic insertion and precise positioning.
Solution Approach 2:
The electrode array exhibits local quality differentiation where the proximal portion has higher stiffness to follow the outer lateral wall smoothly for minimal trauma, while the distal portion has lower stiffness to enable precise positioning near the modiolar wall. This spatial variation in mechanical properties allows the array to perform both functions optimally at different locations along its length.
Data Source
AI summary
An implantable electrode array for a cochlear implant has an array trunk that extends along a center axis from an insertion opening in an outer surface of a patient cochlea into the scala tympani. An apical section extends along the center axis from a distal end of the array trunk and a basal branch is separate from the array trunk and extends back from the distal end of the array trunk towards the insertion opening. The apical section follows along an outer lateral wall of the scala tympani during surgical insertion to attain a final insertion position towards the outer lateral wall in an apical portion of the scala tympani beyond a first basal turn of the cochlea. The basal branch attains a final insertion position towards an inner modiolar wall by the first basal turn of the cochlea with the basal branch stimulation contacts facing the inner modiolar wall.