Rotatable Cannula Fixation Mechanism for Surgical Access Stability
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Solution Overview
Problem
Maintaining the position of a surgical access device relative to the body wall during minimally invasive procedures, particularly in pressurized environments, is challenging due to undesired movement.
Innovation Solution
A rotatably actuated fixation mechanism with a flange and radially-expandable fixation sleeve that expands and contracts via rotation, securing the cannula body to the tissue using a fixation sleeve and anchor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixation mechanism is used to maintain the position of the surgical access device relative to the body wall, then stability is improved, but device complexity increases
Solution Approach 1:
The fixation mechanism employs a dynamic expansion system where the fixation sleeve can transition between compressed and expanded states. The sleeve includes expansion elements that can be actuated to increase the radial profile, creating greater friction engagement with the cannula body and enhancing positional stability only when needed during the procedure.
Solution Approach 2:
The fixation sleeve is disposed within the cannula body in a nested configuration, allowing it to be stored in a compact state during insertion. The sleeve can be expanded outward from its nested position to engage with the cannula body, providing fixation without permanently increasing the device's external dimensions.
2Stability of the object's composition
If an expandable anchor is used to prevent undesired movement, then position maintenance is improved, but ease of operation deteriorates
Solution Approach 1:
The fixation mechanism replaces complex multi-component mechanical anchoring systems with a simpler friction-based engagement system. The fixation sleeve creates radial friction against the cannula body through its expanded profile, eliminating the need for threads, clips, or multiple locking mechanisms while maintaining effective position maintenance.
3Adaptability or versatility
If the fixation sleeve is made from mesh or shape-memory material, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The fixation sleeve utilizes shape-memory materials that change their physical parameters in response to thermal or mechanical stimuli. The material can transition from a flexible, compliant state during insertion to a rigid, expanded state for fixation, allowing adaptation to different tissue conditions while maintaining manufacturability through established shape-memory alloy or polymer fabrication processes.
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 mechanism effectively maintains the cannula's position by resisting proximally-directed forces, ensuring stability during surgical procedures.
Implementation Method 1
Rotation of the flange about the longitudinal axis relative to the elongated portion of the cannula body causes the radially-expandable portion of the fixation sleeve to move between a first position defining a first gap between the radially-expandable portion of the fixation sleeve and the elongated portion of the cannula body, and a second position defining a second gap between the radially-expandable portion of the fixation sleeve and the elongated portion of the cannula body. The second gap is greater than the first gap.
Data Source
AI summary
A surgical access device includes a cannula body and a fixation mechanism. The cannula body includes a housing, and an elongated portion extending distally from the housing and defining a longitudinal axis. The fixation mechanism includes a flange, a fixation sleeve, and a proximal sleeve. The flange is rotatable about the longitudinal axis. The fixation sleeve extends distally from the flange and radially surrounds a portion of the elongated portion of the cannula body. The proximal sleeve extends distally from the flange and radially surrounds a proximal portion of the fixation sleeve. Rotation of the flange causes a radially-expandable portion of the fixation sleeve to move between a first position defining a first gap between the radially-expandable portion and the elongated portion, and a second position defining a second, greater, gap between the radially-expandable portion and the elongated portion.