Ultrasonic Probe Carriage Control for Calcified Occlusion Crossing
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Solution Overview
Problem
Existing ultrasonic catheters face challenges in effectively engaging and navigating through calcified vascular occlusions during crossing and atherectomy procedures due to the hardness of proximal end caps, leading to unintended sub-intimal migration.
Innovation Solution
An ultrasonic probe assembly with a slidable carriage and transducer system that allows for distinct operation modes, including a crossing mode and an atherectomy mode, enabling controlled advancement and retraction of the engagement end while restricting movement in certain directions to enhance user control and engagement efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distal tip of the ultrasonic catheter engages the proximal end cap of the calcified vascular occlusion, then the catheter can potentially cross the occlusion, but the distal tip may unintentionally bounce off the hard proximal end cap and take a sub-intimal migration path into the side wall of the vasculature
Solution Approach 1:
The ultrasonic transducer is made movable relative to the handle through a sliding carriage mechanism, allowing dynamic adjustment of the engagement end position. This enables the operator to optimize engagement depth and angle in real-time, transforming a static engagement problem into a dynamically controllable process that adapts to the specific geometry of the occlusion and vessel.
Solution Approach 2:
The system changes the engagement parameters by allowing longitudinal movement of the ultrasonic transducer relative to the handle. This parameter adjustment (position of engagement end) enables optimization of the interaction between the catheter tip and the proximal end cap, allowing for controlled engagement that prevents bouncing off while ensuring reliable occlusion crossing.
2Ease of operation
If the ultrasonic transducer is allowed to move freely in both proximal and distal directions during atherectomy, then the procedure can be performed, but the hardness of the proximal end cap causes the distal tip to bounce off and migrate sub-intimally
Solution Approach 1:
The carriage mechanism provides dynamic control by allowing the transducer to move along the longitudinal axis while maintaining the handle's stationary position. This dynamic adjustment capability enables the operator to control engagement depth and prevent uncontrolled bouncing off the proximal end cap, thereby improving reliability while preserving ease of operation.
3Ease of operation
If the handle is moved during the procedure to advance or retract the ultrasonic catheter, then the engagement end position can be adjusted, but the handle stability relative to the patient is compromised
Solution Approach 1:
The system segments the adjustment function from the stable support function. The carriage mechanism handles the adjustment of engagement end position by moving the transducer along the longitudinal axis, while the handle remains stationary and stable relative to the patient. This segmentation allows independent optimization of both ease of operation and stability.
Solution Approach 2:
The carriage acts as an intermediary mechanism between the stationary handle and the movable ultrasonic transducer. It mediates the adjustment of engagement end position without requiring movement of the entire handle, thereby maintaining handle stability while enabling precise control of the catheter engagement.
4Device complexity
If a single ultrasonic catheter design is used for both crossing and atherectomy procedures, then device complexity is reduced, but the distinct operational requirements of each procedure cannot be fully met
Solution Approach 1:
The ultrasonic catheter is designed with multi-functionality to perform both crossing and atherectomy procedures. The key enabling feature is the movable transducer mechanism that can be adjusted to different positions and operational modes, allowing a single device to adapt to the distinct requirements of different procedures without requiring separate specialized catheters.
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 system provides enhanced user control over the ultrasonic catheter's engagement and retraction, effectively navigating through vascular occlusions by allowing separate and controlled operation modes, thereby improving the efficacy of crossing and atherectomy procedures.
Implementation Method 1
An ultrasonic system having an ultrasonic catheter may be used in performing crossing and atherectomy procedures
Data Source
AI summary
An ultrasonic probe assembly includes a handle configured to be handheld, and has a housing that defines a chamber. A carriage is slidably coupled to the housing. The carriage has an operator arm configured to be operable by a user to move the carriage between a first position and a second position. An ultrasonic catheter has a catheter sheath and an ultrasonic core wire. The ultrasonic catheter has a proximal end portion and a distal end portion. An ultrasonic transducer is positioned in the chamber of the housing. The ultrasonic transducer is connected to the proximal end portion of the ultrasonic catheter, and the ultrasonic transducer is connected to the carriage. The ultrasonic transducer is configured to longitudinally move in the chamber of the housing between a retracted position and an extended position coincident with a corresponding longitudinal movement of the carriage.