Polyaxial Bone Screw System for Minimally Invasive Spinal Stabilization

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Solution Overview

Problem

Current minimally invasive bone stabilization techniques, particularly in spinal applications, are invasive and difficult to perform, often causing tissue damage and requiring large incisions, leading to long recovery times and adverse events. Existing dynamic posterior stabilization systems either restrict natural spinal motion or fail to adequately address facet joint disorders, and there is a need for systems that allow easier insertion, multiple degree of freedom adjustment, and reduced fatigue failures.

Innovation Solution

A bone screw system with a polyaxial seat and pivoting rod mechanism that allows for alignment and stabilization of vertebral segments with misaligned screws, featuring a cap and set screw system for rotational locking and reduced stress on components, compatible with other pedicle screw systems and spinal implants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional open surgical techniques are used for bone stabilization, then adequate exposure and attachment can be achieved, but large incisions and significant tissue manipulation are required leading to long recovery times and increased risk of adverse events

Engineering Contradiction:

Improvestabilization effectivenessVSAvoidtissue trauma and scarring

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stabilization system is divided into separate modular components including pedicle screws, rod segments, and connection elements that can be inserted and assembled through small incisions, eliminating the need for large open surgical exposure while maintaining stabilization effectiveness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rod is inserted through the pedicle screws in a nested configuration, with the rod passing through the screw bodies and securing mechanisms, allowing all components to be introduced through a single small incision point rather than requiring separate large incisions for each component

Inventive Principle:

Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If minimally invasive techniques are used for spinal stabilization, then tissue damage is reduced, but the procedures become difficult to perform especially when attachment points are deeper in tissue

Engineering Contradiction:

Improvetissue damageVSAvoidprocedure difficulty

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

A guide wire and delivery system act as intermediaries to precisely position the pedicle screws through small incisions, with the guide wire providing a track for instrument insertion and the delivery system enabling controlled placement of deep-lying attachment points without requiring extensive tissue dissection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The pedicle screws are pre-loaded with securing mechanisms and the rod is pre-shaped to match the spinal curvature, allowing these components to be quickly assembled through small incisions without requiring complex intraoperative manipulation or adjustment

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If rigid stabilization systems are used, then structural stability is achieved, but natural spinal motion is restricted and stress on components increases

Engineering Contradiction:

Improvestructural stabilityVSAvoidnatural spinal motion

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The connection between rod segments incorporates dynamic elements such as flexible joints or controlled-motion interfaces that allow the stabilization construct to adapt to physiological spinal movements while maintaining structural integrity, preventing stress concentration and component failure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The rod material and connection elements are designed with controlled flexibility parameters that allow selective rigidity - providing structural stability in the longitudinal direction while permitting controlled motion in physiological directions, thus maintaining both stability and adaptability

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If complex multi-component systems are used for stabilization, then adequate stabilization and adjustment capability are achieved, but device complexity increases and insertion forces required increase

Engineering Contradiction:

Improveadjustment capabilityVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple stabilization functions are merged into integrated components - the pedicle screws incorporate both anchorage and rod-retention functions, the rod provides both structural support and alignment guidance, eliminating the need for separate components for each function and reducing overall system complexity while maintaining adjustment capability

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8267969B2Screw systems and methods for use in stabilization of bone structures

Publication Date: 2012.09.18 CHOICE SPINE LLC

AI summary

Methods, systems, devices and tools for placing bone stabilization components in a patient are provided. The systems and devices have a reduced number of discrete components that allow placement through small incisions and tubes. More particularly, the present invention is directed to screws for use in systems and methods of treating the spine, which eliminate pain and enable spinal motion, which effectively mimics that of a normally functioning spine. Methods are also provided for installation of the screw and other subject systems.