Angular Positioning System for Rotary Surgical Instruments
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Solution Overview
Problem
Existing rotary surgical cutting instruments face inefficiencies due to uncontrolled alignment of inner and outer cutting windows during oscillation cycles, leading to debris clogging and reduced cutting efficiency, which prolongs surgical procedures and can result in tissue pinching or tearing.
Innovation Solution
An angular positioning system that uses sensors to automatically align the inner and outer cutting windows during rotation reversals, ensuring optimal alignment and maintaining fluid pressure, thereby improving cutting efficiency and adaptability to intra-procedural conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If open-loop time-based control system is used to oscillate the inner tubular member, then the oscillation can be achieved, but the alignment of inner and outer cutting windows becomes uncontrolled leading to debris clogging and reduced cutting efficiency
Solution Approach 1:
The patent implements a closed-loop control system that uses sensors (optical encoders, Hall effect sensors) to detect the angular position of the inner tubular member and provides feedback to the controller. The controller adjusts the motor drive signals based on this feedback to ensure precise alignment of the inner and outer cutting windows at the end of each oscillation cycle, preventing debris clogging and maintaining cutting efficiency.
Solution Approach 2:
The patent replaces the open-loop time-based mechanical control system with an electronic closed-loop control system using a controller and angular position sensors. This substitution enables precise control of the inner tubular member's angular position through electronic feedback rather than relying solely on mechanical timing, achieving both oscillation and precise alignment.
2Loss of time
If the inner cutting window comes to a stop in an uncontrolled angular orientation, then the oscillation cycle can be completed quickly, but debris clogging occurs and surgical procedure length increases
Solution Approach 1:
The closed-loop control system continuously monitors the angular position of the inner tubular member using angular position sensors and adjusts the motor drive in real-time. This feedback mechanism ensures that the inner cutting window stops at the precisely aligned position with the outer cutting window, maximizing debris evacuation rate through the suction passage and preventing clogging that would prolong the surgical procedure.
Solution Approach 2:
The control system is designed to proactively align the cutting windows before the oscillation cycle completes, ensuring optimal positioning is achieved in advance. The controller calculates the required motor torque and timing to bring the inner tubular member to the aligned position, preventing debris accumulation before it becomes a problem rather than reacting to it after clogging occurs.
3Manufacturing precision
If manual intervention is added to align cutting windows, then alignment precision improves, but device complexity and ease of operation deteriorate
Solution Approach 1:
The control system is designed to automatically align the inner and outer cutting windows without requiring manual intervention from the surgeon. The angular position sensors and controller work together to self-correct the angular position of the inner tubular member, making the alignment process autonomous. This eliminates the need for additional manual alignment mechanisms while maintaining high precision.
Solution Approach 2:
The automated feedback control system continuously monitors angular position and makes real-time adjustments to maintain precise alignment. This feedback mechanism replaces what would otherwise require complex manual alignment mechanisms, simplifying the overall device design while achieving high alignment precision through intelligent control rather than mechanical complexity.
4Productivity
If suction flow rate is increased to improve debris evacuation, then cutting efficiency improves, but fluid pressure control becomes difficult leading to tissue pinching or tearing
Solution Approach 1:
The control system monitors the angular position feedback to synchronize suction activation with the alignment of cutting windows. By controlling suction to operate at optimal moments during the oscillation cycle when the cutting windows are aligned, the system achieves high debris evacuation rates while maintaining safe fluid pressure levels that prevent tissue pinching or tearing through precise temporal coordination rather than simply increasing suction power.
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 angular positioning system enhances the rate of debris and fluid evacuation, reduces procedure length, and maintains fluid pressure, improving visibility and cutting efficiency while adapting to surgical needs without requiring user intervention.
Implementation Method 1
an angular position sensor to provide to the controller, with respect to at least one of the inner and outer tubular members, an indication of angular orientation therebetween
Implementation Method 2
A rotary cutting instrument can be used with an external vacuum source to provide suction through the inner cutting window, to evacuate surgical debris from the surgical site
Implementation Method 3
The irrigation fluid can generally enter a surgical site through a gap defined between the inner tubular member and outer tubular member
Data Source
AI summary
A powered surgical instrument can include a cutting assembly including an outer tubular member defining an outer cutting window, an inner tubular member arranged to be rotatable concentrically within the outer tubular member and defining an inner cutting window, and a control system. The control system can include a controller, an angular position sensor to provide to the controller, with respect to at least one of the inner and outer tubular members, an indication of angular orientation therebetween to allow the controller to control the angular orientation of the inner cutting window relative to the outer cutting window, without requiring user intervention, such that the inner and outer cutting windows are aligned when relative rotation between the inner and outer tubular members is stopped or paused.