Telescoping Cannula Helical Thread Length Adjustment
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Solution Overview
Problem
Conventional cannula assemblies for minimally invasive surgeries lack a reliable length adjustment mechanism, leading to suboptimal placement of surgical instruments and potential exposure of internal organs due to fixed cannula lengths that do not accommodate varying body cavity wall thicknesses or the need for instruments of different lengths.
Innovation Solution
A telescoping cannula assembly with a length adjustment structure featuring a helical thread and inter-engaging components, allowing for adjustable length extension and retraction, and a length fixation mechanism using indentations and a male rib for secure positioning, enabling precise placement of surgical instruments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed length cannula is used, then the structure is simple, but it cannot accommodate varying body cavity wall thicknesses and instrument lengths
Solution Approach 1:
The cannula transitions from a fixed length design to a dynamically adjustable length design. The inner cannula can be extended or retracted relative to the outer cannula through a threaded engagement mechanism, allowing the overall length to be adjusted based on the patient's anatomy and surgical requirements. This dynamic adjustment capability resolves the contradiction by enabling adaptability without requiring multiple fixed-length cannulas.
Solution Approach 2:
The inner cannula is nested within the outer cannula, with the inner cannula having a threaded outer surface that engages with a threaded inner surface of the outer cannula. This nesting arrangement allows the inner cannula to be selectively extended or retracted while maintaining a compact configuration when retracted, solving the contradiction between adaptability and structural simplicity.
2Adaptability or versatility
If the cannula extends beyond the body cavity wall to accommodate deep organ access, then deep organ access is enabled, but excessive external extension increases trauma and exposure risk
Solution Approach 1:
The adjustable length mechanism allows the cannula to be precisely positioned with minimal external extension. By extending only the necessary portion of the inner cannula, the design enables access to deep organs while minimizing the portion of the cannula exposed to external contaminants and reducing trauma to the body cavity wall.
3Adaptability or versatility
If different length instruments are used for various surgical needs, then surgical versatility is improved, but instrument protrusion beyond the cannula increases complexity
Solution Approach 1:
The adjustable inner cannula allows the overall cannula length to be matched to the instrument length. By extending the inner cannula to provide adequate support for longer instruments or retracting it for shorter instruments, the design accommodates various surgical instrument lengths without requiring excessive protrusion or complex external support structures.
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 flexible and secure introduction of surgical instruments across a range of body cavity wall thicknesses, reducing trauma and exposure risks while accommodating various surgical instrument lengths, thus enhancing surgical precision and efficiency.
Implementation Method 1
The length adjustment structure includes a generally helical thread on at least one of the elongate members and feature on the other for engaging the thread
Implementation Method 2
The inter-engaging components may include a series of indentations arranged in a generally helical pattern corresponding to the generally helical thread
Data Source
Figure 1
Figure 2~3C
AI summary
An apparatus may serve as a surgical portal for the reception of surgical instruments for use in laparoscopic or similar surgery. The apparatus may include inner and outer tubular elongate members adapted for a longitudinal translation relative to one another to effect a length adjustment of the apparatus. An interface between the two elongate members includes a helical thread providing a mechanism for the translation of the elongate members, and indentations in one of the members provides a locking mechanism for affixing the length.