Reciprocating Inner Cannula Tissue Cutting Device
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Solution Overview
Problem
Existing tissue cutting devices for neurosurgical procedures face challenges in quickly and cleanly severing neurological tissue without causing traction or damage, lacking flexibility, and are often unsuitable for both bulk debulking and fine shaving, with issues of emulsification, maceration, or thermal damage that render tissue unsuitable for analysis.
Innovation Solution
A tissue cutting device with a hand-held design featuring a reciprocating inner cannula within a fixed outer cannula, driven by a motor, allowing for high-speed cutting and variable aspiration, equipped with a rotating outer cannula for precise orientation and a tissue collector for efficient sample retrieval, using materials like stainless steel for durability and a hinge mechanism for effective cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed reciprocating cutting is used to quickly sever tissue, then cutting speed is improved, but tissue trauma and emulsification increase
Solution Approach 1:
The inner cannula performs high-speed reciprocating motion with periodic engagement and disengagement from the outer cannula cutting edge. The cutting action occurs only during brief engagement periods, allowing high cutting speed while limiting continuous tissue trauma. The periodic nature of the reciprocating motion enables rapid tissue severing while providing intervals that reduce cumulative thermal and mechanical damage to surrounding tissue.
Solution Approach 2:
The outer cannula acts as an intermediary between the inner cannula and the tissue. The outer cannula's cutting edge engages with the tissue while the inner cannula reciprocates, creating a controlled cutting mechanism. This intermediary structure allows the cutting action to be distributed and controlled, reducing direct trauma from high-speed reciprocating motion while maintaining cutting efficiency.
2Device complexity
If a single cutting mechanism is used, then device simplicity is improved, but versatility for both bulk debulking and fine shaving is reduced
Solution Approach 1:
The device employs dynamic adjustment of the inner cannula's reciprocating motion parameters, including stroke length, speed, and engagement depth with the outer cannula. By dynamically varying these parameters, the single cutting mechanism can adapt to different surgical requirements - deeper engagement for bulk debulking, shallower engagement for fine shaving - without requiring multiple specialized tools.
Solution Approach 2:
The cutting mechanism's operational parameters (reciprocation amplitude, frequency, and engagement depth) can be changed to achieve different cutting modes. The inner cannula's motion characteristics are adjustable, allowing the same physical structure to perform both aggressive bulk tissue removal and delicate fine shaving by simply modifying motion parameters rather than changing the physical configuration.
3Productivity
If thermal cutting methods are used to quickly remove tissue, then cutting efficiency is improved, but tissue integrity for analysis is compromised
Solution Approach 1:
The invention replaces thermal cutting mechanisms with a mechanical reciprocating cutting system. The inner cannula's mechanical reciprocating motion, combined with the outer cannula's cutting edge, severs tissue through controlled mechanical action rather than thermal degradation. This mechanical approach maintains tissue integrity by avoiding the emulsification and carbonization associated with thermal methods, while still achieving efficient tissue removal through high-speed reciprocation.
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
Enables precise and efficient cutting of neurological tissues with minimal trauma, allowing for both bulk removal and fine shaving, while maintaining tissue integrity for analysis, and providing ergonomic benefits for surgeons in confined spaces.
Implementation Method 1
an inner cannula (76) configured to reciprocate within the outer cannula lumen (110) and cut tissue samples entering the outer cannula opening (49)
Implementation Method 2
configured for variable aspiration, and/or combinations of both high speed reciprocation and variable aspiration
Data Source
AI summary
A tissue cutting device that is especially suited for neurosurgical applications is disclosed and described. The device includes a handpiece and an outer cannula in which a reciprocating inner cannula is disposed. The inner cannula may include a hinge between a body section and a cutting section that allows the cutting section to pivot when the inner cannula reciprocates within the outer cannula. A tissue collector may also be provided and is in fluid communication with the lumen of the inner cannula. The inner cannula reciprocates at a rate that is greater than 1000 reciprocations per minute, and variable aspiration may also be provided to the device to control tissue traction and provide fine shaving and debulking.