Surgical Spinal Tether Constraint for Flexion Stability

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Solution Overview

Problem

Existing spinal treatments often result in excessive motion or loading at adjacent spinal segments, leading to degeneration and damage to prostheses and surrounding tissue, particularly during flexion, which is the largest component of intervertebral motion and most frequently exercised.

Innovation Solution

A surgical method and apparatus that utilize a constraint device with adjustable tethers and compliance members to resist spinal segment flexion, modulating loads on prostheses and adjacent tissue, while allowing natural motion and minimizing invasive procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If spinal fusion is performed to treat spinal disorders, then spinal stability is improved, but excessive motion occurs at adjacent spinal segments leading to degeneration

Engineering Contradiction:

Improvespinal stabilityVSAvoidexcessive motion at adjacent segments

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The constraint device is divided into multiple independent components: upper and lower tethers, compliance members, and adjustment mechanisms. This segmentation allows the device to be implanted separately from the fusion procedure and to provide targeted constraint at specific spinal segments without affecting the entire spine.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The constraint device acts as an intermediary mechanism between the fused spinal segment and the adjacent segments. By providing flexion constraint at the adjacent levels, it mediates the excessive motion that would otherwise occur due to the fusion, thereby protecting adjacent segments from degeneration.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stress or pressure

If flexion constraint is applied to reduce loading on the disc, then disc loading is reduced, but natural spinal motion is restricted

Engineering Contradiction:

Improvedisc loadingVSAvoidnatural spinal motion

Core Design Contradiction:

Stress or pressureVSEase of operation

Solution Approach 1:

The constraint device incorporates dynamic elements including compliance members that can deform under load and adjustment mechanisms that allow the tension in the tethers to be modified. This dynamic design enables the device to provide flexion constraint while allowing necessary spinal motion and adapting to changing physiological conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The device allows for changes in the tension parameter of the tethers through adjustment mechanisms. The tension can be modified to optimize the balance between providing sufficient flexion constraint to reduce disc loading and maintaining enough flexibility to preserve natural spinal motion.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If rigid constraint is applied to stabilize the spinal segment, then flexion stability is improved, but damage to prostheses and tissue increases

Engineering Contradiction:

Improveflexion stabilityVSAvoiddamage to prostheses and tissue

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The constraint device utilizes flexible tethers and compliance members rather than rigid structures. The tethers are designed to be flexible enough to accommodate spinal motion while providing sufficient constraint to stabilize the segment. The compliance members provide flexible support that reduces stress concentrations and minimizes damage to prostheses and surrounding tissue.

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 method and apparatus provide additional flexion stability, reduce excessive loading, and minimize damage to prostheses and tissue by indirectly stabilizing the spinal segment, reducing the risk of failure and promoting natural motion and healing.

Implementation Method 1

a compliance member (16) coupled therebetween. An upper portion of the constraint device is engaged with a superior spinous process and a lower portion of the constraint device is engaged with an inferior spinous process or a sacrum. The length or tension in the constraint device is adjusted so that the construct of the tethers and compliance member provides a force resistant to flexion of the spinal segment.

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20250302509A1Surgical tether apparatus and methods of use

Publication Date: 2025.10.02 EMPIRICAL SPINE INC

AI summary

A spinal treatment system includes a constraint device having an upper tether portion, a lower tether portion and a compliance member coupled therebetween. The upper tether portion is coupled with a superior spinous process of a spinal segment in a patient and the lower tether portion is coupled with an inferior spinous process or sacrum of the spinal segment. The length or tension in the constraint device is adjustable so that the construct of the tether portions and the compliance member provides a force resistant to flexion of the spinal segment. The system also includes a first prosthesis coupled with the spinal segment, wherein the constraint device modulates loads borne by the prosthesis or by tissue adjacent thereto.