Concentric Tissue Cutter Sleeves for Small-Lumen Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hysteroscopic resection devices with small diameters face challenges in preventing resected tissue from lodging in the lumens of small diameter hysteroscopes, necessitating improvements to enhance tissue extraction efficiency.
Innovation Solution
The use of a tissue cutting device with concentric outer and inner sleeves, where the inner sleeve reciprocates to cut and capture tissue through a window, utilizing a partial vacuum and a displacement feature to push resected tissue into a larger proximal lumen section, reducing the risk of clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a small diameter hysteroscope is used for fibroid resection, then the invasiveness is reduced and cervical dilation is minimized, but the resected tissue easily becomes lodged in the small diameter lumens
Solution Approach 1:
The lumen is segmented into multiple sections with varying cross-sectional areas. The distal portion has a smaller cross-sectional area for initial tissue capture, while the proximal portion has a larger cross-sectional area to prevent lodging and facilitate extraction. This segmentation allows the lumen to perform different functions at different locations.
Solution Approach 2:
The solution transitions from a uniform one-dimensional lumen to a variable cross-sectional area lumen. By changing the cross-sectional area along the length of the lumen (adding a dimensional variation), the system can both capture small tissue fragments in the distal region and prevent lodging in the proximal region, resolving the contradiction between small diameter and reliable extraction.
2Ease of operation
If a small diameter hysteroscope is used, then the procedure can be performed with less anesthesia and in a less invasive manner, but the tissue removal lumen becomes prone to clogging
Solution Approach 1:
Different portions of the lumen are given different cross-sectional areas to optimize local functions. The distal portion has a smaller area suitable for initial tissue capture, while the proximal portion has a larger area to ensure smooth extraction. This local differentiation allows the single lumen to efficiently perform both tissue capture and extraction without clogging.
3Reliability
If conventional resectoscopes with larger diameter are used, then tissue extraction is more reliable, but cervical dilation to about 9 mm is required and anesthesia in operating room environment is necessary
Solution Approach 1:
The cutting instrument with its variable cross-sectional area lumen is nested within the hysteroscope. This nested configuration allows the cutting instrument to maintain its own optimized lumen geometry for reliable tissue extraction while being delivered through a small diameter hysteroscope, thus achieving both minimal invasiveness and reliable extraction.
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 solution effectively reduces the likelihood of resected tissue becoming lodged in the device lumens, ensuring smooth and efficient extraction of fibroid tissue through small diameter hysteroscopes.
Implementation Method 1
Typically, a partial vacuum will be drawn on the inner sleeve lumen, to draw the resected tissue into the inner sleeve lumen.
Data Source
AI summary
The tissue cutting device comprises an elongated assembly including both an outer sleeve and an inner sleeve. The outer sleeve has a tissue-receiving window, and the inner sleeve has a distal end which cuts tissue as the inner sleeve is advanced past the window. The tissue is received into a lumen of the inner sleeve, and the inner sleeve lumen is typically enlarged in a proximal direction to reduce the tendency of resected tissue to lodge therein. The tissue displacement member is optionally provided at a distal end of the outer sleeve to further aid in dislodging tissue which becomes captured in a distal end of the inner sleeve of the lumen.