Bioabsorbable Band System With Pawl Locking Mechanism

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Solution Overview

Problem

Current surgical band and crimp systems for securing bones are prone to improper tensioning, slippage, and adverse tissue reactions due to mechanical incompatibility with bone tissue, leading to complications such as non-union, breakage, and delayed healing, especially in chest surgery and orthopedic procedures.

Innovation Solution

A bioabsorbable band system with a needle system and a bioabsorbable locking mechanism that provides precise tensioning and secure locking around bones, utilizing a bioabsorbable band with oriented structure and pawl teeth locking mechanism, made from polymers like polylactide, and a flexible needle system to minimize stress concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal crimp systems are used to secure bones, then the bone fragments can be fixed together, but the extremely stiff metal materials are mechanically incompatible with bone tissue causing osteolysis and implant migration

Engineering Contradiction:

Improvefixation strengthVSAvoidosteolysis and implant migration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameters from metal to bioabsorbable polymer, transforming the mechanical properties to be more compatible with bone tissue. The polymer material has lower stiffness and is gradually absorbed by the body, eliminating the harmful effects of metal implants while maintaining sufficient fixation strength during the healing process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite construction with the bioabsorbable band and locking mechanism made from polymer materials that combine adequate mechanical strength for fixation with biocompatibility and gradual degradation properties, creating a material system that is mechanically compatible with bone tissue.

Inventive Principle:

Principle #40Composite materials

2Reliability

If cable loop or winding is used for locking, then the bone can be secured, but there is an inevitable drop in tension when pliers are removed leading to tensioning errors

Engineering Contradiction:

Improvebone fixation reliabilityVSAvoidtensioning precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The locking mechanism is designed to be pre-loaded or pre-tensioned during the crimping process, with the locking geometry configured to maintain the desired tension automatically. The pawl teeth and ratchet mechanism are shaped to engage in a way that preserves tension without requiring additional adjustment after plier removal.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional cable loop or winding mechanical locking system with a crimp-based locking mechanism that uses localized deformation and geometric interlocking (pawl teeth engagement) to maintain tension, eliminating the tension drop problem associated with loop-based systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If traditional crimp systems are used, then cable fixation can be achieved, but slippage of the cable in the crimp can occur leading to delayed healing

Engineering Contradiction:

Improvecrimping easeVSAvoidcable retention reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The pawl teeth are designed with asymmetric geometry where the engagement direction allows easy insertion and locking, but the release direction is blocked by the tooth profile. This asymmetric design prevents cable slippage in the loosening direction while maintaining ease of application during the crimping process.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The crimp structure incorporates built-in tension maintenance features that compensate for potential slippage before it occurs. The locking geometry is designed with clearance and engagement surfaces that ensure positive locking and prevent cable movement that could lead to slippage during the healing process.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If bulky crimps are used for locking, then secure fixation can be achieved, but adverse tensioning in surrounding tissues occurs resulting in negative effect on tissue healing

Engineering Contradiction:

Improvefixation securityVSAvoidadverse tissue tensioning

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a thin, flexible bioabsorbable band instead of bulky crimps. The band can conform to the bone surface and surrounding tissues, distributing the fixation force over a larger area and reducing localized tensioning that would adversely affect tissue healing, while the locking mechanism provides secure fixation.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS8512379B2Bioabsorbable band system, a bioabsorbable band, a method for producing a bioabsorbable band, a needle system of a bioabsorbable band and a locking mechanism

Publication Date: 2013.08.20 BIORETEC

AI summary

A bioabsorbable band system for securing a bone fracture, or an osteotomy, or a soft tissue on a bone. The bioabsorbable band system includes a needle system and a bioabsorbable band including a bioabsorbable locking member. The bioabsorbable band includes a length having an at least partially oriented structure. The bioabsorbable band further includes a locking mechanism with a locking member. Also a method for producing the bioabsorbable band.