Distraction Sleeve for Bone Anchor Parallel Manipulation

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Solution Overview

Problem

Traditional bone anchor distraction systems face challenges such as interference during polyaxial distraction, difficulty in achieving true parallel distraction, and cumbersome rod and set screw requirements, which complicate spinal surgery procedures like discectomy and interbody work.

Innovation Solution

A distraction sleeve that can be preloaded onto a bone anchor assembly to lock or limit the polyaxial degree of freedom without directly engaging the shank or exterior of the bone anchor, allowing for true parallel distraction without the need for rods or closure mechanisms, and can be easily inserted with the aid of a selectively detachable driver and protection/sheath systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional distraction systems grip the outer portion of the receiver member, then distraction can be applied to the bone anchor assembly, but interference occurs when adjacent receiver members abut against one another making proper placement difficult

Engineering Contradiction:

Improveease of distraction instrument placementVSAvoidmechanical interference between adjacent receiver members

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The distraction sleeve serves as an intermediary component that couples the distraction instrument to the bone anchor assembly's internal threading rather than gripping the external receiver member. This intermediary approach eliminates mechanical interference between adjacent receiver members while still enabling effective distraction forces to be applied to the implanted bone anchor.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If distraction systems grip the outer portion of the receiver member, then distraction can be applied, but true parallel distraction cannot be achieved unless rods and set screws are also placed within the receiver member

Engineering Contradiction:

Improveparallel distraction accuracyVSAvoidrequirement for rods and set screws

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts the distraction function from the complex rod-and-set-screw mechanism and integrates it directly into the bone anchor assembly through internal threading. The distraction sleeve with its internal threads allows true parallel distraction to be achieved by engaging the bone anchor's shank directly, eliminating the need for separate rods and set screws while maintaining precise parallel distraction capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If distraction tools are fed over a receiver member after insertion, then the distraction system can be attached to the bone anchor assembly, but the process becomes difficult and time-consuming

Engineering Contradiction:

Improvesurgical procedure efficiencyVSAvoidtime to attach distraction tool

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The distraction sleeve is designed to be pre-loaded onto the bone anchor assembly before insertion into the bone. The selective detachability allows the sleeve to be attached in advance, so that when the bone anchor assembly is implanted, the distraction capability is already integrated and ready for immediate use, eliminating the time-consuming post-insertion attachment process.

Inventive Principle:

Principle #10Preliminary action

4Manufacturing precision

If rods and set screws are placed within the receiver member to lock off polyaxial degree of freedom, then true parallel distraction can be achieved, but the procedure becomes cumbersome for surgeons

Engineering Contradiction:

Improveparallel distraction capabilityVSAvoidsurgeon workflow simplicity

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The invention merges the distraction sleeve functionality with the bone anchor assembly's internal threading structure. The distraction sleeve integrates the polyaxial locking mechanism and distraction interface into a single component that engages the shank internally, combining what were previously separate functions (rod placement, set screw insertion, and distraction) into one streamlined system that maintains parallel distraction capability while simplifying the surgical workflow.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9949731B2Systems and methods for manipulating bone

Publication Date: 2018.04.24 MEDOS INT SARL

AI summary

Systems and methods are disclosed in which a distraction sleeve can be attached to a bone anchor assembly to lock or limit the polyaxial degree of freedom of the bone anchor assembly and facilitate true parallel distraction. In some embodiments, the distraction sleeve can lock polyaxial movement of the bone anchor assembly without directly engaging the shank of the bone anchor assembly, without directly engaging the exterior of the receiver member of the bone anchor assembly, and/or without requiring that a rod or closure mechanism be installed in the bone anchor assembly. The distraction sleeve can be preloaded onto the bone anchor assembly prior to inserting the bone anchor assembly using a selectively detachable driver, thereby providing simplified, streamlined insertion and facilitating use with protection and/or retraction sheaths. Countertorque tubes, torque wrenches, and other related instrumentation are also disclosed herein.