Pivoting Cap Rod Construct for Minimally Invasive Spinal Implant Insertion

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Solution Overview

Problem

Current minimally invasive spinal osteosynthesis techniques face challenges in reliably and efficiently inserting and securing fixation rods between implants through smaller incisions, leading to a steep learning curve and tissue disturbance due to limited visualization and complex manipulation deep within the incision.

Innovation Solution

A minimally invasive implant system featuring a pair of spinal implants with elongated posts and pivotally mounted caps, along with percutaneous access tubes, allows for the secure insertion and deployment of a fixation rod, eliminating the need for separate rod positioning in transverse openings by using a cap/rod construct that pivots from a longitudinal to a perpendicular orientation within the access tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a minimally invasive approach with smaller incisions is used, then muscle damage and tissue disturbance are reduced, but the complexity of inserting and securing fixation rods increases

Engineering Contradiction:
Improvemuscle damageVSAvoidrod insertion complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the fixation rod with the cap assembly to form an integrated cap/rod construct. This merging eliminates the need for separate rod positioning operations and simplifies the minimally invasive insertion process by delivering both components through a single access tube in one maneuver.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fixation rod is designed to pivot from a longitudinal orientation (aligned with the access tube) to a perpendicular orientation (aligned with the transverse rod receiving opening). This dynamic reorientation allows the rod to be inserted through the access tube and then automatically positioned into the transverse opening without requiring separate positioning operations.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If traditional open surgery with large incisions is used, then visualization and manipulation are easier, but muscle stripping and postoperative pain increase

Engineering Contradiction:
ImprovevisualizationVSAvoidmuscle stripping
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces percutaneous access tubes as intermediary devices that serve as conduits for delivering implants and fixation rods through small incisions. These access tubes provide a protected pathway that maintains visualization and manipulation capabilities while minimizing muscle damage by avoiding direct muscle stripping.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If separate rod positioning operations are performed, then precise rod placement can be achieved, but procedural time and complexity increase

Engineering Contradiction:
Improverod placement precisionVSAvoidprocedural time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The fixation rod is pre-positioned within the cap assembly in a longitudinal orientation aligned with the access tube before insertion. This preliminary positioning allows the rod to be automatically oriented into the correct transverse position upon insertion, eliminating the need for separate positioning operations and reducing procedural time while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2293741B1Minimally invasive implant system for immobilizing adjacent vertebral bodies
Publication Date: 2015.05.13 SEASPINE
  • EP2293741B1 patent drawingFigure 1a~2
  • EP2293741B1 patent drawingFigure 3
  • EP2293741B1 patent drawingFigure 4a~4b

AI summary

A spinal implant system for use in immobilizing adjacent vertebral bodies in a minimally invasive manner, including a pair of implants having lengths { sufficient so that one of the ends extend outside of a patient's body when the implants are installed. Each implant has a pair of opposed elongated posts which in conjunction with an orthogonally arranged support surface define a transverse opening for receiving a stabilizing rod. A cap having upper and lower surfaces is associated with each implant, each cap and it's associated post has means for advancing the cap along the posts toward the support surface to lock a stabilizing rod therebetween. The rod is pivotally coupled to one of the caps so that the rod, when pivoted, will extend between the transverse openings in adjacently installed implants.