Motorized Surgical Stapler Power Control and Torque Limiting
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Solution Overview
Problem
Current surgical staplers for endoscopic and laparoscopic applications lack efficient power control and torque management, and their RF electrode configurations are not optimized for effective tissue coagulation, leading to potential damage and suboptimal surgical outcomes.
Innovation Solution
The development of cordless motor-powered surgical instruments with a DC power source and cell selection switch for power control, torque-limiting devices, and innovative RF electrode configurations featuring smaller active and larger return electrodes to concentrate energy and minimize tissue impact, along with segmented electrodes for sequential activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a DC power source with cell selection switch is implemented, then motor speed and power control is improved, but device complexity increases
Solution Approach 1:
The power source system is made dynamically adjustable through the cell selection switch, allowing the operator to change the number of battery cells engaged (e.g., 2-cell, 4-cell, 6-cell configurations) to match different motor power requirements. This dynamic reconfiguration enables precise control over motor speed and power output without requiring complex electronic regulators.
2Object-affected harmful factors
If torque-limiting devices are added, then protection against tissue damage is improved, but device complexity increases
Solution Approach 1:
A torque-limiting device is introduced as an intermediary component between the motor and the surgical end effector. This device acts as a protective mediator that allows controlled torque transmission during normal operation while automatically limiting excessive torque to prevent tissue damage, effectively decoupling the motor's full capability from the tissue interface.
3Use of energy by moving object
If RF electrodes are configured with smaller active and larger return electrodes, then energy concentration for coagulation is improved, but manufacturing complexity increases
Solution Approach 1:
The RF electrode system applies local quality differentiation by using smaller active electrodes (e.g., 2-5mm diameter) concentrated at the tissue interface for high-energy coagulation, while pairing them with larger return electrodes (e.g., 10-20mm diameter) positioned away from the tissue for heat dissipation. This non-uniform electrode geometry optimizes energy distribution locally at the critical tissue interface while simplifying overall system manufacturing.
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 solution provides precise control over motor speed and power, limits actuation forces to prevent damage, and enhances RF energy application for effective tissue coagulation, improving surgical precision and safety.
Implementation Method 1
A battery, such as a Li ion battery, may be provided in the pistol grip portion to power a motor
Implementation Method 2
The battery powers a motor disposed in an upper portion of the pistol grip portion
Implementation Method 3
it is also known in the prior art to include electrodes in the end effector that can be used to emit/receive RF energy to form a hemostatic line along the cut line
Data Source
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AI summary
A surgical cutting and fastening instrument (10). The instrument (10) comprises an end effector (12), a shaft (8) connected to the end effector (12), and a handle (6) connected to the shaft (8). The handle (6) comprises an electric, DC motor (65) connected to a drive train in the shaft (8) for powering the drive train. The handle (6) also comprises a power pack (299) that comprises at least one charge-accumulating device connected to the DC motor (65) for powering the DC motor (65).