Elliptical Retractor for Laparoscopic Incision Stability
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Solution Overview
Problem
Current laparoscopic wound retractors with flexible cylindrical sleeves face challenges in maintaining a circular incision shape due to rigidity limitations, which affects the stability and accessibility during surgical procedures.
Innovation Solution
An elliptically shaped retractor system comprising a rigid upper ring, a flexible lower ring, and an elastic sheath with an elliptical passageway, where the perimeter is expressed as a function of its small and large diameters, optimizing the incision shape to approach a circular configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the rigidity of the cylindrical sleeve is increased to maintain a circular cross-section, then the circular shape is preserved, but the placement of the sleeve into the incision opening becomes difficult
Solution Approach 1:
The retractor sheath is designed with dynamic shape transformation capability - it can be compressed into an elliptical shape for easy insertion through the incision opening, then automatically transforms into a circular cross-section once placed inside the abdominal cavity. This dynamic adaptation allows the device to overcome the contradiction between insertion ease and shape maintenance.
Solution Approach 2:
The retractor sheath utilizes changes in geometric parameters (from elliptical to circular cross-section) in response to different environmental conditions. The material properties and structural design enable the sheath to change its shape parameters based on whether it is being inserted or is in its functional state, resolving the contradiction between ease of placement and circular shape maintenance.
2Stability of the object's composition
If the rigidity of the cylindrical sleeve is increased to maintain circular shape, then the incision opening stability is improved, but the accessibility during surgical procedures deteriorates
Solution Approach 1:
The retractor sheath provides dynamic adaptation to surgical needs - maintaining circular stability during the procedure while allowing compression for instrument insertion. This dynamic behavior ensures both incision stability and accessibility without requiring extreme rigidity that would compromise maneuverability.
Solution Approach 2:
The retractor sheath is constructed from composite materials that combine different mechanical properties - sufficient rigidity to maintain circular shape and provide incision stability, yet flexible enough to be compressed for instrument passage. This composite construction resolves the contradiction between stability and accessibility.
3Shape
If the retractor sheath is made extremely rigid to maintain circular cross-section, then the circular shape is preserved, but the retractor cannot be compressed for placement
Solution Approach 1:
The retractor sheath is designed with dynamic shape transformation - it can be compressed into an elliptical shape for placement, then automatically returns to a circular cross-section once positioned. This dynamic capability eliminates the need for extreme rigidity while maintaining circular shape, resolving the contradiction between shape preservation and compressibility.
Solution Approach 2:
The retractor sheath is pre-formed with a circular cross-section in its functional state, but can be temporarily deformed into an elliptical shape during insertion. This preliminary design allows the sheath to be compressed for placement while maintaining its circular identity, resolving the contradiction between manufacturability and shape maintenance.
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 elliptical retractor design enhances the stability and accessibility of the incision by maximizing the convergence of incision dimensions to form a circular shape, reducing spinning and improving retraction performance.
Implementation Method 1
an elastic sheath extending between the upper retractor ring and the lower retractor ring
Data Source
AI summary
A retractor for use in laparoscopic procedures includes an upper retractor ring, a lower retractor ring, and a retractor sheath extending between the upper retractor ring and the lower retractor ring to form a tubular passageway through which instruments or a medical practitioner's hands may pass during a medical procedure. The retractor sheath includes an elliptical passageway extending between lower retractor ring and the upper retractor ring.