Shape Memory Alloy Surgical Patty for Dura Retraction
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Solution Overview
Problem
Existing laminectomy procedures lack a surgical patty that effectively isolates the dura from cutting tools, as current patties do not have a structural architecture or spring action to expand and retract the dura away from the decompression site during bone removal.
Innovation Solution
A shape retention surgical patty made from a shape memory alloy, such as nitinol, integrated with absorbent materials like cotton or rayon, which is crimped and inserted through a tube to expand and fill the epidural space, gently retracting the dura away from cutting tools as the lamina is decompressed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional absorbent surgical patty is used during laminectomy, then the patty can absorb fluid and provide basic protection, but the patty lacks structural architecture to expand and retract the dura away from cutting tools
Solution Approach 1:
The surgical patty combines an absorbent material layer with a shape memory alloy support structure, creating a composite device that provides both fluid absorption and mechanical expansion capability. The shape memory alloy framework gives the patty structural integrity and spring action, while the absorbent material provides fluid management functions, resolving the contradiction between protection reliability and device complexity.
Solution Approach 2:
The shape memory alloy support structure changes its physical parameters (shape, volume, rigidity) in response to temperature changes or mechanical deformation. When heated or released from a compressed state, the alloy transitions from a collapsed configuration to an expanded three-dimensional structure, enabling the patty to actively retract the dura away from cutting tools during laminectomy procedures.
2Reliability
If the patty expands to fill the epidural space and retract the dura, then protection is improved, but the patty must be inserted in a compressed state requiring additional manipulation
Solution Approach 1:
The shape memory alloy support structure is designed to nest within itself or collapse into a compact configuration that can be inserted through a surgical retractor or delivery device. Once positioned in the epidural space, the alloy structure automatically expands to its full three-dimensional configuration, providing the necessary protection without requiring complex manual manipulation during insertion.
Solution Approach 2:
The shape memory alloy support structure is pre-formed into a specific three-dimensional configuration that provides optimal dura retraction and protection. This pre-formed structure is then compressed or collapsed for insertion, and upon deployment, it automatically returns to its pre-formed shape through shape memory effect, eliminating the need for complex intraoperative manipulation to achieve the protective configuration.
3Reliability
If a shape memory alloy support structure is added to the patty, then the patty can expand into the epidural space and retract the dura, but the manufacturing complexity increases
Solution Approach 1:
The surgical patty is divided into distinct functional components: a shape memory alloy support structure and an absorbent material layer. The support structure can be manufactured separately using additive manufacturing or forming techniques specific to shape memory alloys, then integrated with the absorbent material through bonding or mechanical attachment. This segmentation allows each component to be optimized and manufactured using appropriate processes, reducing overall manufacturing complexity.
Solution Approach 2:
The shape memory alloy support structure and absorbent material are combined into a single integrated surgical patty device. The absorbent material is attached to the support structure, creating a unified device that performs both structural (dura retraction) and functional (fluid absorption) roles. This merging simplifies the overall device assembly and ensures coordinated performance during surgical use.
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 patty effectively protects the dura from accidental damage by expanding into the decompressed epidural space, maintaining a safe distance between the dura and cutting tools, thereby reducing the risk of injury during laminectomy procedures.
Implementation Method 1
a shape retention surgical patty made from a shape memory alloy, such as nitinol
Implementation Method 2
integrated with absorbent materials like cotton or rayon
Data Source
AI summary
Methods and apparatus for retracting the dura away from a cutting tool during a laminectomy procedure. The method includes inserting a memory shape surgical sponge (patty) into an initial epidural space between the dura and the tool used to decompress (e.g., drill) the lamina. As the lamina is further decompressed, the patty tends to spring back toward its nominal position, urging the dura away from the decompression and isolating the dura from the drill.