Nested Calculus Collecting Unit for Safe Stone Extraction

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Solution Overview

Problem

Current methods for removing urinary stones, such as Extracorporeal Shock Wave Lithotripsy and Transurethral Resection of Lithotripsy, face limitations in efficiently extracting multiple stones and broken pieces due to the gripping function of basket forceps and ureteral lumen size, leading to increased operation time, risk of infection, and potential tissue damage.

Innovation Solution

A calculus removing device featuring a retaining portion with a storage unit and introducing portions that allow for the reliable retention and removal of multiple stones and broken pieces without damaging surrounding tissues, using a wire or gel-like material to securely hold and collect calculi within a collecting unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If basket forceps are used to extract stones, then the gripping function is limited by the size of ureteral lumen and basket forceps structure, but the number of calculi and broken pieces that can be removed in one operation is limited

Engineering Contradiction:

Improvenumber of calculi removedVSAvoidgripping function limitation

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The collecting unit is divided into multiple compartments (first collecting unit and second collecting unit) that can be introduced separately through the ureteral lumen. Each compartment can independently collect calculi, allowing multiple stones to be removed in one operation without being constrained by the size of a single basket forceps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first collecting unit and second collecting unit are nested within each other, with both units capable of being introduced through the same ureteral access sheath. This nesting arrangement allows multiple collection chambers to pass through the limited ureteral lumen space, increasing the total number of calculi that can be collected without requiring larger external dimensions.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If basket forceps are inserted and retracted multiple times to remove all calculi, then complete stone removal is achieved, but operation time increases and tissue damage risk increases

Engineering Contradiction:

Improvecomplete stone removalVSAvoidoperation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Multiple collecting units (first and second collecting units) are combined into a single integrated device that can be introduced through one ureteral access sheath. This allows calculi to be collected in multiple compartments simultaneously during a single insertion, eliminating the need for repeated insertions and retractions of separate basket forceps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The device enables continuous collection of calculi in multiple compartments during a single operational phase, maintaining the useful action of stone collection without interruption from repeated insertions. The calculi are collected continuously in different compartments as the device is advanced, reducing total operation time.

Inventive Principle:

Principle #20Continuity of useful action

3Quantity of substance

If multiple calculi are gripped by basket forceps, then more stones can be collected, but end surfaces of calculi expose from gaps between wires and may damage kidney or ureter walls

Engineering Contradiction:

Improvenumber of calculi collectedVSAvoidtissue damage from exposed stone surfaces

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The collecting unit employs a flexible bag-like structure with a smooth inner surface that encloses calculi completely. This flexible shell configuration allows multiple calculi to be contained within the smooth-walled bag, preventing exposed stone surfaces from contacting and damaging the kidney or ureter walls during retrieval, unlike the rigid wire structure of traditional basket forceps.

Inventive Principle:

Principle #30Flexible shells and thin films

4Object-affected harmful factors

If calculi and broken pieces are removed within limited operation time, then infection risk is reduced, but complete removal of all stones may not be achieved

Engineering Contradiction:

Improveinfection riskVSAvoidcomplete stone removal

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The collecting system is segmented into multiple independent collecting units (first and second collecting units) that can be introduced through a single ureteral access sheath. This segmentation allows calculi to be collected in parallel across multiple compartments during one insertion, enabling complete stone removal within the limited safe operation time window without requiring multiple sequential insertions.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10687835B2Calculus removing device

Publication Date: 2020.06.23 TERUMO KK

AI summary

A calculus removing device includes a retaining portion (e.g., a wire or gel), a cylinder, an introduction tube, and a hand-operated unit. The retaining portion is configured to retain calculi and broken calculus pieces. The cylinder includes a storage portion configured to store the calculi, an opening communicating with the storage portion, and an introducing portion configured to permit the retaining portion to be introduced into the storage portion. The introduction tube is provided with a lumen which allows introduction of the retaining portion into the storage portion via the introducing portion. The hand operating unit is provided with an operating member configured to operate the introduction of the retaining portion into the storage portion.