Cannula Illumination Using Focused LED Beams to Reduce Glare
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Solution Overview
Problem
Current cannula systems for minimally invasive surgery, particularly in treating hemorrhagic strokes, face challenges in providing clear visualization of the surgical field due to excessive glare from broad beam angle LEDs, which obscures the camera's view of the target tissue.
Innovation Solution
The cannula system incorporates a camera mounted on the proximal end with powerful LEDs and secondary optics, such as GRIN lenses, to focus the light into a narrow beam angle, reducing glare and enhancing visualization while allowing for minimal intrusion into the cannula lumen for tool passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If broad beam angle LEDs are used for illumination, then illumination coverage is improved, but glare increases obscuring the camera view
Solution Approach 1:
The patent applies local quality by using multiple LEDs with different beam angles positioned at specific locations within the cannula. Broad beam angle LEDs provide general illumination coverage, while narrow beam angle LEDs provide focused illumination where needed. Each LED's beam characteristics are optimized for its specific position and function, resolving the contradiction between coverage and glare.
Solution Approach 2:
The patent introduces reflective surfaces and diffusing elements as intermediaries between the LEDs and the surgical field. These intermediaries modify the light paths to reduce direct glare while maintaining illumination coverage. The reflective surfaces redirect light at angles that illuminate the workspace without creating blinding glare for the camera.
2Illumination intensity
If powerful LEDs are mounted at the distal end of the cannula, then illumination at the workspace is improved, but the cannula structure becomes more complex
Solution Approach 1:
The patent segments the illumination system by using multiple smaller LEDs distributed along the cannula length rather than one powerful LED at the distal end. This segmentation allows the illumination function to be achieved through multiple low-power components, simplifying the overall structural requirements while maintaining adequate workspace illumination.
Solution Approach 2:
The patent transitions from a single-point illumination source at the distal end to a distributed linear arrangement of LEDs along the cannula. This dimensional change from point-source to line-source illumination provides adequate lighting without requiring the cannula to extend as far or support as much concentrated light output at the tip.
3Loss of information
If a camera is mounted on the proximal end of the cannula, then visualization is improved, but the cannula lumen becomes more obstructed for tool passage
Solution Approach 1:
The patent applies nesting by placing the camera within or alongside the cannula structure in a compact arrangement. The camera is integrated into the proximal end assembly, nested within the overall device architecture, minimizing its protrusion and obstruction of the cannula lumen while maintaining adequate visualization capability.
Solution Approach 2:
The patent uses curved or angled camera mounting arrangements that follow the natural geometry of the cannula. The camera is positioned and oriented to capture the surgical field without requiring a large straight-line projection into the lumen, utilizing angular and curved positioning to reduce obstruction.
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
This configuration provides improved illumination with reduced glare, enabling clear visualization of the surgical workspace and facilitating precise surgical interventions with minimal obstruction for surgical tools.
Implementation Method 1
US 5,036,834 discloses a light box feeding into a connector rod feeding into tube filled with a fiber optic bundle which in turn feeds into the proximal end of an endoscope, and includes a lens to focus light from the light box into the fiber optic bundle to promote total internal reflection in the fiber optic bundle
Implementation Method 2
The secondary optics may comprise a GRIN lens, configured to focus light from the LED to a narrow beam angle for transmission through the cannula to the workspace at the distal end of the cannula
Data Source
Figure 1
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AI summary
A cannula with a proximally mounted camera and proximally mounted light sources. The lighting sources have beam axes directed distally, toward a workspace at the distal end of the cannula. The light sources are coupled with focusing lenses, to reduce the beam angle of the lighting sources and reduce glare within the cannula tube.