Sheathed Wire Saw for Safe Total Contact Cast Removal

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Solution Overview

Problem

Conventional methods for removing total contact casts pose risks of skin injury and are time-consuming, with traditional cast saws creating dust hazards for healthcare workers, leading to low adoption rates among clinicians.

Innovation Solution

A cutting assembly featuring a flexible metal cutting wire or cable, enclosed in a plastic sheath, is integrated into the cast system, allowing for safe and efficient removal by pulling the wire saw through the cast material without the need for oscillating blades.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a traditional cast saw is used to cut through the cast materials, then the cast can be removed, but dust is created which creates a hazardous environment for health care workers

Engineering Contradiction:
Improvecast removal efficiencyVSAvoiddust hazard
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the traditional oscillating mechanical cast saw with a wire saw system that uses a flexible metal cutting wire or cable. This substitution eliminates the dust-generating oscillating blade mechanism while maintaining cast-cutting capability through a different mechanical approach (wire pulling through cast material).

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cutting wire is enclosed in a plastic sheath that acts as a flexible protective covering. This sheath contains the cutting action and prevents dust generation while allowing the wire to effectively cut through the cast material. The flexible nature of the sheath allows it to navigate within the cast structure.

Inventive Principle:
Principle #30Flexible shells and thin films

2Productivity

If pressure is applied to the cast saw during removal, then the cast can be cut, but the oscillating blade penetrates the cast padding and potentially cuts or burns the patient's skin

Engineering Contradiction:
Improvecast removal speedVSAvoidskin injury risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The plastic sheath serves as an intermediary between the cutting wire and the patient's skin/padding. It contains the cutting action within the hard cast material while preventing the wire from contacting or penetrating the soft padding and skin, thereby eliminating the risk of thermal or mechanical injury to the patient.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The oscillating blade mechanism that causes skin burning and padding penetration is replaced with a wire pulling mechanism. The wire saw cuts through the cast material by being pulled through it, eliminating the oscillating motion that generates heat and causes tissue damage while maintaining effective cast removal capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If conventional cast removal methods are used, then the cast can be removed, but it requires significant strength and is very time consuming

Engineering Contradiction:
Improvecast removal easeVSAvoidcast removal time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces the conventional cast saw requiring significant operator strength with a wire saw system. The flexible wire can be pulled through the cast material with minimal force, dramatically reducing the physical strength requirement while maintaining effective cast removal capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The flexible plastic sheath containing the wire allows the cutting mechanism to navigate through the cast structure efficiently. This flexibility enables the wire to follow the cast contours and cut through material more easily compared to rigid saw blades, reducing both time and force requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

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 enables quicker, safer, and dust-free removal of total contact casts, reducing the risk of skin injury and improving operational efficiency for medical personnel, thereby increasing the use of total contact casting in treating diabetic and neuropathic foot ulcers.

Implementation Method 1

A wire saw is a flexible metal cutting wire or cable, optionally serrated, which uses abrasion for cutting rather than saw teeth

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3562453B1Total contact cast system and methods for safe and easy removal thereof
Publication Date: 2022.01.26 WOUNDKAIR CONCEPTS INC
  • EP3562453B1 patent drawingFigure 1~2
  • EP3562453B1 patent drawingFigure 3~4
  • EP3562453B1 patent drawingFigure 5~6

AI summary

A cast system, which includes: a padding layer configured to be disposed within a cast and support a portion of a patient's limb; a casting material which hardens around the padding layer and form an outer shell of the cast surrounding the patient's limb; and a wire saw configured to be disposed within the cast and extend along a longitudinal axis of the cast. The wire saw has a cutting surface which is at least partly enclosed by a plastic sheath. By enclosing the wire saw cutting surface in a plastic sheath, the saw does not lock up during the cutting operation, cutting is facilitated, allowing for easy and safe removal of the cast by pulling at least one end of the wire saw so as to cut through the outer shell of the cast.