Laparoscopic Scissors Low-Profile Actuation
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Solution Overview
Problem
Prior laparoscopic scissors with actuation rods and slots result in high-profile extensions of the blades, which can interfere with tissue or other devices during use and cause deformation of insulation tubing, leading to issues with trocar withdrawal.
Innovation Solution
A laparoscopic scissor design featuring curved or parabolic cutting blades with a pivot and actuation protrusions, where the actuation mechanism is slidable within an elongate shaft, reducing the operational height and minimizing interference with tissue or insulation sheaths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blades have slots proximal to a pivot location with traditional actuation rod configuration, then the blades can be actuated to open and close, but the proximal portions of the blades extend out beyond the outside diameter of the scissors shaft creating high-profile extensions
Solution Approach 1:
The invention moves the actuation mechanism from a lateral slot configuration to a longitudinal groove configuration along the blade length. This dimensional change allows the actuation rod to engage the blade through the groove rather than through a lateral slot, eliminating the need for proximal extensions and reducing the blade profile to remain within the shaft diameter.
Solution Approach 2:
The invention uses a curved or parabolic cutting profile for the blade edges. This curvature provides enhanced cutting performance while allowing the blade to maintain a streamlined, low-profile shape that stays within the shaft diameter during actuation.
2Ease of operation
If the proximal portions of the blades extend out beyond the outside diameter of the scissors shaft, then the blades can be actuated, but the extended wings can catch on or interfere with tissue or other devices during use
Solution Approach 1:
By transitioning from lateral slot actuation to longitudinal groove actuation, the invention eliminates the protruding wing structures that cause tissue interference. The groove runs along the length of the blade, allowing actuation without requiring proximal extensions beyond the shaft diameter.
3Reliability
If plastic shrink tubing is used to cover the wings during electro-surgical cautery, then insulation is provided, but the wings can stretch and deform the shrink tubing when the blades are open
Solution Approach 1:
The invention removes the problematic wing structures that cause tubing deformation. By eliminating the proximal extensions through the use of longitudinal grooves instead of lateral slots, there is no protruding structure to stretch or deform the shrink tubing during blade actuation.
4Ease of operation
If the deformed tubing does not relax when the scissors are withdrawn from a trocar, then the scissors can be removed, but the deformed tubing may catch on the end of the cannula, thereby pulling the trocar out of the patient
Solution Approach 1:
By eliminating the wing structures that cause tubing deformation, the invention prevents the chain of events leading to trocar dislodgement. Without protruding wings to stretch the tubing, the insulation remains intact and does not catch on the cannula during withdrawal.
5Ease of operation
If traditional actuation rod with pin and slot configuration is used, then the blades can be actuated, but the proximal portions of the blades are relatively large in size
Solution Approach 1:
The invention transitions from lateral slot actuation requiring large proximal portions to longitudinal groove actuation that allows slender blade design. The groove extends along the blade length, enabling actuation force transmission without requiring large proximal blade sections.
Data Source
AI summary
A laparoscopic scissor instrument can include a scissor assembly pivotally coupled to an elongate shaft. The scissor assembly can be formed of scissor blades having pivot posts thereon. The pivot posts can engage apertures on the elongate shaft, thus eliminating the need for a through-pinned pivot connection of the scissor blades. The scissor blades can also include actuation posts thereon. An actuation mechanism can include a slot to engage the actuation posts and open or close the blades of the scissor assembly. The scissor assemblies described herein can have a relatively low operational height such that they do not extend beyond a diameter of the elongate shaft during opening and closing of the scissor assembly.