Spiral Growth Tether With Frangible Release for Bone Malrotation

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Solution Overview

Problem

Current surgical methods for correcting bone rotational deformities, such as osteotomy, are invasive and carry significant risks and complications, including pain, infection, and the need for secondary procedures.

Innovation Solution

A spiral growth tether system is secured to a bone via coupling members and a tether that allows for rotational correction by separating as the bone grows, using a frangible region to break at a groove or apertures, allowing the bone to grow without invasive procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional osteotomy surgery is used to correct bone rotational deformities, then rotational alignment can be corrected, but the procedure becomes invasive with significant risks including pain, infection, and need for secondary procedures

Engineering Contradiction:

Improvecorrection effectivenessVSAvoidsurgical complications

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The tether is divided into a proximal portion and a distal portion separated by a frangible middle section. This segmentation allows the tether to function as a complete constraint during bone growth, then automatically separate when the bone reaches the desired correction, eliminating the need for secondary removal procedures and avoiding surgical complications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The frangible middle section is pre-configured with a groove or aperture that creates a predetermined weak point. This preliminary structural preparation ensures that when tension from bone growth reaches a certain threshold, the tether will break at the intended location, automatically releasing the correction constraint without requiring additional surgical intervention.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If osteotomy with plates and screws is performed to hold corrected bone portions, then rotational alignment is corrected, but significant pain and risk of neurovascular injury occur

Engineering Contradiction:

Improvebone alignment stabilityVSAvoidneurovascular injury risk

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention replaces the rigid mechanical fixation system (plates and screws penetrating the bone) with a soft tissue-based tether system. The tether applies continuous tensile force to maintain corrected alignment during healing, then automatically releases when the bone is sufficiently healed, eliminating risks associated with metal implants and repeated surgeries.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The frangible middle section of the tether is designed to automatically break when the bone reaches a predetermined level of healing and strength. This self-service mechanism eliminates the need for secondary surgical procedures to remove implants, reducing patient pain, infection risk, and neurovascular injury potential while maintaining alignment stability during the critical healing period.

Inventive Principle:

Principle #25Self-service

3Duration of action of stationary object

If long plate and screws or intramedullary rod are implanted to hold transected bone portions, then corrected rotational alignment is maintained pending healing, but large incision and risk of surgical site infection increase

Engineering Contradiction:

Improvealignment maintenance periodVSAvoidsurgical site infection risk

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The tether is designed as a temporary, single-use implant that serves its purpose during the bone healing period and then automatically decommission itself through the frangible section breaking. This disposable approach eliminates the need for long-term implants that would require removal surgery, reducing surgical site infection risk and eliminating the need for second procedures while maintaining alignment throughout the healing duration.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Manufacturing precision

If traditional osteotomy procedure is used, then rotational deformity can be corrected, but delayed bone healing or non-union may occur

Engineering Contradiction:

Improverotational correction precisionVSAvoidbone healing reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The tether system changes the mechanical environment parameters during bone healing by applying controlled tensile force across the osteotomy site. This continuous gentle traction promotes osteogenesis and accelerates healing compared to rigid fixation, while the frangible design ensures the tether releases automatically when healing is complete, preventing delayed union or non-union while maintaining precise rotational correction.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12453588B2Spiral growth tether systems and methods

Publication Date: 2025.10.28 STEVENS PETER M

AI summary

A spiral growth tether system may be securable to a bone having a growth plate that separates a first portion of the bone from a second portion of the bone. The spiral growth tether system may include a tether including a first end configured to be secured to the first portion, a second end configured to be secured to the second portion, and a central portion between the first end and the second end. The first end and the second end may be configured to separate at the central portion in response to the first end being urged away from the second end as a result of growth of the bone urging the first portion away from the second portion.