Cortical Rim-Supporting Interbody Device for Subsidence Prevention
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Solution Overview
Problem
Subsidence of implanted interbody cages is a risk, particularly in patients with lower bone density, due to insufficient peripheral structural support, which existing fusion techniques fail to adequately address.
Innovation Solution
A percutaneous method involving a central inflatable distractor and a perimeter balloon is used to create a horseshoe-shaped structural support, where the perimeter balloon is filled with a curable material that contacts the vertebral endplates, allowing for the removal of the distractor and subsequent packing with graft for fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fusion cage is inserted into the disc space to treat low back pain, then spinal fusion is achieved, but the risk of subsidence increases due to insufficient peripheral structural support
Solution Approach 1:
The structural support is divided into two distinct components: a central inflatable distractor for vertical separation and a peripheral balloon for circumferential support. This segmentation allows each component to address specific subsidence risks in different locations, with the peripheral balloon specifically providing cortical rim support to prevent posterior wall subsidence.
Solution Approach 2:
The peripheral balloon is specifically positioned to contact the cortical rim of the vertebral endplates, providing localized structural support exactly where subsidence most commonly occurs. This local quality approach concentrates support where it is most needed rather than providing uniform support throughout the disc space.
2Ease of operation
If a curable material is flowed into a balloon placed in the disc space to form a fusion cage in-situ, then minimally invasive fusion is achieved, but the structural support at the peripheral cortical rim is insufficient
Solution Approach 1:
The system separates the functions of disc space separation and peripheral structural support into two independent components. The central inflatable distractor handles separation while the peripheral balloon provides circumferential support, allowing minimally invasive delivery while achieving robust peripheral support that single-balloon designs cannot provide.
Solution Approach 2:
The solution combines two different functional elements (central inflatable distractor and peripheral balloon) into a composite interbody device system. This composite approach integrates the advantages of both components: minimally invasive delivery, disc separation, and enhanced peripheral structural support that neither component could achieve alone.
3Device complexity
If the peripheral cortical rim is not adequately supported, then the fusion cage can be simpler to implant, but the risk of subsidence increases particularly in patients with lower bone density
Solution Approach 1:
The device is segmented into a central component for simplicity of insertion and a peripheral component for subsidence resistance. The peripheral balloon can be delivered through the same minimally invasive pathway as the central distractor, maintaining implant simplicity while adding the necessary peripheral support structure to prevent subsidence in osteopenic patients.
Solution Approach 2:
The peripheral balloon is inflated and positioned before the curable material is injected, establishing peripheral structural support in advance. This preliminary action ensures that the cortical rim is adequately supported before the fusion material sets, preventing subsidence during the critical healing period.
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 method provides immediate load-bearing support to the cortical rim while allowing central fusion, reducing the risk of subsidence and enhancing fusion stability, especially in patients with lower bone density.
Implementation Method 1
the perimeter balloon is filled with a curable material that contacts the vertebral endplates
Implementation Method 2
The central inflatable distractor is then expanded, thereby distracting the vertebral endplates to the controlled height of the central inflatable distractor
Data Source
AI summary
A central inflatable distractor and a perimeter balloon are inserted into the disc space in uninflated configurations. The central inflatable distractor is then expanded, thereby distracting the vertebral endplates to the controlled height of the central inflatable distractor. The perimeter balloon is then inflated with a curable substance. The perimeter balloon expands as it is filled with the curable substance and conforms to the void remaining in the disc space around the central inflatable distractor, thereby creating a horseshoe shape. Once the flowable material in the perimeter balloon has cured, the central inflated distractor can be deflated and removed. The remaining void (or inner space) is then packed with graft for fusion.