Intervertebral Disc Prosthesis With Replaceable Core
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Solution Overview
Problem
Existing intervertebral disc revision methods, particularly in the lumbar spine, are risky due to blood vessel scarring and require extensive bone removal, often necessitating fusion, which limits patient mobility and causes adjacent spine degeneration.
Innovation Solution
A method and prosthesis that allows for the replacement of the core of an intervertebral disc while leaving the endplates intact, using minimally invasive surgical approaches such as lateral, anterior, or oblique, with tools engaging features on the plates to detach and replace the core without removing the entire implant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If total explantation of the artificial disc is performed to replace a worn core, then the worn core can be removed, but it causes extensive bone removal and damages to the bony vertebral body structures, making further artificial disc replacement impossible
Solution Approach 1:
The artificial disc is divided into separable components: the core and the endplates. The endplates are designed with detachment features that allow the core to be separated from the endplates during revision surgery, enabling core replacement while preserving the endplates and avoiding extensive bone removal.
Solution Approach 2:
The core is extracted as a separate replaceable component from the endplates. The endplates remain implanted in the vertebrae while the worn core is removed and replaced, eliminating the need to remove the entire artificial disc and causing minimal bone damage.
2Reliability
If the artificial disc is removed and fusion is performed to treat back pain, then the pain can be treated, but the patient's ability to move is reduced and adjacent spine degeneration is accelerated
Solution Approach 1:
The endplates are recovered and preserved after the core is replaced. By retaining the endplates in place, the natural motion between vertebrae is maintained, avoiding the mobility restriction and adjacent degeneration that occur with fusion surgery.
3Adaptability or versatility
If the entire artificial disc including endplates is extracted to replace it, then a new disc can be installed, but extensive bone removal is required and the procedure becomes very difficult and dangerous
Solution Approach 1:
The artificial disc is segmented into the core and endplates, with the endplates designed to remain implanted while the core is replaced. This segmentation simplifies the revision procedure by eliminating the need to remove the entire disc and perform extensive bone removal.
4Stability of the object's composition
If fusion is performed to stabilize the spine after disc removal, then structural stability is achieved, but the back cannot bend or twist at the fused area and adjacent levels experience increased stress
Solution Approach 1:
The endplates are recovered and retained in the spinal column after core replacement. This allows the vertebrae to maintain their natural motion capability while providing structural stability through the preserved endplates, avoiding the need for fusion and its associated mobility restrictions.
Data Source
AI summary
An intervertebral disc prosthesis is described including two endplates and a revisable elastic core. The existing core is removed while leaving the two endplates intact in the spine. A new core is installed between the endplates. The new core can have mechanical properties similar to or different than the originally implanted core. The new design enables the intervertebral disc prosthesis to be revised in situ using minimally invasive surgery.