Laser Catheter Pulsating Beam Vessel Wall Ablation
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Solution Overview
Problem
Existing laser catheters for bypass surgery, such as the ELANA technique, face challenges in effectively cutting through the vessel wall without causing unnecessary damage or incomplete removal of the 'flap' during ETS-anastomosis, leading to potential obstruction of blood flow.
Innovation Solution
A laser catheter system with a fibre bundle of optical fibres emitting a pulsating ultraviolet light beam at an ablation power of at least 40 mJ/mm² per pulse, controlled by an excimer laser and a timing device for predefined emitting and break intervals, ensuring precise cutting of the vessel wall while preventing cutting through both sides of the vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser catheter uses higher ablation power to cut through the vessel wall more effectively, then the cutting effectiveness is improved, but there is a risk of cutting through both sides of the vessel causing damage
Solution Approach 1:
The laser catheter emits pulsating light beams with a duty cycle of 10-50%, delivering high ablation power during pulse intervals while allowing cooling and tissue recovery between pulses. This periodic action enables effective cutting at 40-100 mJ/mm² peak power without causing excessive thermal damage to the opposite vessel wall, as the intermittent nature of the pulses allows heat dissipation and prevents continuous thermal accumulation that would lead to through-cutting.
2Manufacturing precision
If the laser catheter emits continuous light beam to ensure complete removal of the flap, then the completeness of flap removal is improved, but the risk of heating and burning damage to surrounding tissue increases
Solution Approach 1:
The system uses pulsating laser beams with duty cycles of 10-50% to deliver high ablation energy in intermittent bursts rather than continuous exposure. This periodic delivery allows the tissue to cool between pulses, preventing thermal accumulation and burning damage to surrounding healthy tissue while still achieving complete flap removal through cumulative ablation effect over multiple pulses.
Solution Approach 2:
The laser system dynamically adjusts the ablation power parameter to 40-100 mJ/mm² during pulse intervals and reduces it to near-zero during break intervals. This parameter modulation enables precise control of the ablation process, achieving complete flap removal through controlled cumulative energy delivery while preventing thermal damage by periodically reducing the energy input below the damage threshold.
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 increased ablation power and pulsating frequency enhance the effectiveness of cutting away the flap without causing damage to the opposite vessel wall, ensuring complete removal and minimizing the risk of blood flow obstruction.
Implementation Method 1
a laser apparatus, comprising one or more lasers for supplying light to the optical fibres
Implementation Method 2
a fibre bundle of optical fibres having distal ends defining a light emitting surface for emitting a light beam
Implementation Method 3
emitting a pulsating light beam with an ablation power of at least 40 mJ/mm²
Implementation Method 4
The tubular bundle of the laser light beam ablates a circle into the wall of the target vessel
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c~2d
AI summary
A catheter system is provided comprising a laser catheter with a fibre bundle of optical fibres emitting a light beam in the distal direction of the catheter and a laser apparatus, comprising one or more lasers for supplying light to the optical fibres. The catheter system is preset or adjusted for emitting a pulsating light beam with an ablation power of at least 40 mJ/mm2 per pulse at the location of a light emitting surface. A method for preparing such a catheter system is provided comprising the step of a) measuring said ablation power at the location of the light emitting surface; b) comparing the measured ablation power with a predefined power value requirement; c) in case the measured ablation power is different from the predefined power value requirement, adjusting the ablation power of the pulsating light beam to meet the predefined power value requirement.