Perimeter Balloon Interbody Device for Vertebral Endplate Subsidence
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Solution Overview
Problem
Subsidence of implanted interbody cages is a risk in fusion procedures, particularly in patients with lower bone density, due to uneven strength distribution across vertebral endplates, where the central region is weaker than the peripheral region.
Innovation Solution
A method involving the insertion of a central distractor and a perimeter balloon into the disc space, where the perimeter balloon surrounds the central distractor, both expanding to distribute distraction load across a large majority of the vertebral endplate area, minimizing subsidence risk by leveraging the stronger peripheral region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fusion cage is implanted in the central region of the disc space, then the procedure is simpler and more direct, but the risk of subsidence increases due to weaker bone density in the central region
Solution Approach 1:
The balloon device is designed with non-uniform geometry where the peripheral region extends further laterally than the central region. This creates local quality differentiation in load distribution, concentrating distraction forces on the stronger peripheral bone while still achieving central disc space opening. The peripheral balloon portion specifically targets the cortical rim region which has higher bone density and load-bearing capacity.
Solution Approach 2:
The invention transitions from a traditional central-only implantation approach to a three-dimensional balloon structure that extends in multiple dimensions. The balloon's lateral extension into the peripheral region adds a spatial dimension to force distribution, allowing simultaneous engagement of both central and peripheral bone structures to prevent subsidence.
2Force
If larger lift forces are applied to distract the disc space, then fusion effectiveness is improved, but the risk of endplate fracture increases in patients with lower bone density
Solution Approach 1:
The balloon device creates localized quality in force application by extending preferentially into the peripheral region. This allows high lift forces to be applied safely by concentrating them on the stronger peripheral cortical bone, while the central region receives distributed support. The peripheral balloon portion acts as a load-bearing element that leverages the stronger peripheral bone to enable higher overall lift forces without increasing fracture risk.
3Reliability
If the balloon is designed to contact the cortical rim, then subsidence risk is reduced, but the device complexity increases
Solution Approach 1:
The balloon is designed as a dynamic, expandable structure rather than a rigid fixed geometry device. When inflated, the balloon naturally conforms to the disc space anatomy and makes contact with the cortical rim through controlled expansion. This dynamic adaptation allows the simple balloon structure to achieve complex cortical rim engagement without requiring intricate mechanical components or adjustment mechanisms.
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
This approach effectively distributes the distraction load across the strongest part of the bone, reducing the risk of subsidence and allowing for larger lift forces, even in patients with lower bone density, while minimizing the risk of endplate fracture.
Implementation Method 1
A method involving the insertion of a central distractor and a perimeter balloon into the disc space, where the perimeter balloon surrounds the central distractor, both expanding to distribute distraction load across a large majority of the vertebral endplate area
Data Source
AI summary
An inflatable central distractor is inserted in to a disc space between two vertebral endplates. A perimeter balloon is inserted into the disc space in such a manner as to surround the central inflatable distractor. The perimeter balloon and the central inflatable distractor are simultaneously expanded such that as the central inflatable distractor expands the perimeter balloon surrounds the central inflatable distractor and such that the central inflatable distractor and the perimeter balloon, when expanded, contribute to forcing adjacent vertebral endplates apart.