Dual-Chamber Nuclear Prosthesis for Disc Pressure Damping
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Solution Overview
Problem
Current clinical options for treating intervertebral disc disorders, such as degenerative disc disease and spinal disc injuries, are inadequate due to the mismatch in modulus of elasticity between implanted materials and adjacent tissues, leading to issues like subsidence, migration, and expulsion of nuclear prostheses, and the inability to dampen sudden pressure changes during extreme spinal movements.
Innovation Solution
A dual-chambered spinal implant device with a flexible body, comprising an outer and inner fillable enclosure, is designed to be implanted using minimally invasive techniques. The device includes a system for controlled inflation and curing of a curable medium within the outer chamber, providing pressure feedback and ensuring proper orientation and fit within the enucleated disc cavity, while incorporating radiopaque markers for precise placement and imaging balloons for cavity assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a nuclear prosthesis is implanted to replace the nucleus pulposus, then the structural support function is restored, but the mismatch in modulus of elasticity causes subsidence, migration, and expulsion of the implant
Solution Approach 1:
The patent changes the physical state of the implant material from rigid to flexible by using a gelatinous material with adjustable modulus of elasticity. This allows the implant to match the mechanical properties of the native nucleus pulposus, preventing subsidence and migration while maintaining structural support. The flexible material can deform with spinal movement rather than resisting it, eliminating the stress concentration that leads to implant expulsion.
Solution Approach 2:
The patent employs composite material strategies by combining gelatinous material with radiopaque markers and potentially other functional components. The gelatinous base material provides the necessary flexibility and shock-absorbing properties, while radiopaque markers enable imaging and positioning verification. This composite approach allows simultaneous achievement of mechanical compatibility and diagnostic visibility.
2Strength
If a rigid implant material is used to provide structural support, then load-bearing capacity is improved, but the ability to dampen sudden pressure changes during extreme spinal movements is lost
Solution Approach 1:
The patent adjusts the modulus of elasticity parameter of the implant material to match that of the native nucleus pulposus. This creates a gelatinous material that is neither too rigid nor too soft, enabling it to absorb and dampen sudden pressure changes during extreme spinal movements while still providing adequate load-bearing capacity for normal spinal function.
Solution Approach 2:
The gelatinous implant material inherently provides cushioning against sudden pressure changes before they can transmit harmful forces to the vertebral endplates and surrounding tissues. The material's viscoelastic properties allow it to deform and absorb impact energy during extreme movements, protecting the spinal structure from shock loads.
3Ease of operation
If minimally invasive surgical techniques are used for implantation, then patient trauma and recovery time are reduced, but the precision of implant placement and orientation is compromised
Solution Approach 1:
The patent incorporates radiopaque markers within the implant that enable visualization under fluoroscopic imaging. These markers allow the surgical team to precisely track the implant's position and orientation in real-time during minimally invasive surgery, ensuring accurate placement without requiring open surgical exposure. The markers create visible contrast against surrounding tissues, enabling precise spatial control.
Solution Approach 2:
The radiopaque markers provide continuous visual feedback during the implantation process, allowing the surgical team to monitor implant position and make real-time adjustments. This feedback mechanism enables precise placement and orientation even through small incisions, reconciling the trade-off between minimally invasive access and placement accuracy.
4Strength
If the implant material has high modulus of elasticity to maintain implant shape, then structural integrity is improved, but softening of vertebral end plates and adjacent bone occurs, leading to subsidence
Solution Approach 1:
The patent fundamentally changes the modulus of elasticity parameter of the implant material from high (rigid) to low (flexible), matching the native nucleus pulposus properties. This flexible gelatinous material distributes loads more evenly across the vertebral endplates, preventing the stress concentration that causes bone softening and subsidence, while still maintaining sufficient structural integrity to perform its load-bearing function.
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
The device effectively replaces the nucleus pulposus, maintaining spinal integrity by dampening sudden pressure changes, preventing subsidence and migration, and ensuring proper implant placement, thus enhancing the physiological function of the intervertebral disc.
Implementation Method 1
The gelatinous material has a modulus of elasticity between 0.01 and 10 MPa, which allows it to dampen sudden pressure changes while maintaining structural integrity
Implementation Method 2
The gelatinous material may contain a radiopaque material that enables imaging and tracking of the implant
Data Source
AI summary
The present disclosure includes devices, apparatuses, kits, and methods for replacing a nucleus pulposus of an intervertebral disc with an implantable nuclear prosthesis filled with a curable silicone material in situ. Configurations of the present spinal implant devices include a flexible body defining an outer fillable enclosure that defines an outer chamber, an inner fillable enclosure that defines an inner chamber, and a proximal plug configured to be coupled to the inner fillable enclosure.