Expandable Vertebral Implant Assembly for Dynamic Spinal Stabilization
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Solution Overview
Problem
Current spinal surgery techniques, such as fusion, often lead to chronic pain and degeneration of adjacent spinal levels, resulting in Failed Back Surgery Syndrome, as they fail to maintain natural anatomy and balance of forces in the vertebral column.
Innovation Solution
The development of an expandable vertebral implant assembly, comprising a prosthetic vertebral body with a fastener receiving member and a pedicle fastener with distinct fastening portions, allows for dynamic integration and alignment with pedicles, maintaining natural anatomy and balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fusion techniques are used to stabilize the spine, then spinal stabilization is achieved, but natural spinal motion is lost and adjacent levels undergo degeneration
Solution Approach 1:
The prosthetic vertebral body includes an expandable cage structure that can be dynamically adjusted post-implantation to restore and maintain disc height and spinal alignment. The device transitions from a compressed delivery state to an expanded functional state, providing dynamic stabilization while preserving adjacent segment motion
Solution Approach 2:
The implant system is divided into separate components: an expandable cage for vertebral body replacement and pedicle fasteners for posterior fixation. This segmentation allows the anterior column to be restored independently while maintaining the ability to provide posterior stabilization if needed, avoiding unnecessary fusion of adjacent levels
2Shape
If fusion techniques are used to correct spinal deformity, then coronal and sagittal balance can be restored, but chronic pain develops and adjacent segments degenerate
Solution Approach 1:
The expandable cage allows for dynamic adjustment of vertebral body height and alignment post-implantation, enabling restoration of coronal and sagittal balance without rigid fusion. The device can be adjusted to achieve optimal spinal alignment while preserving motion at adjacent segments, reducing the development of chronic pain
Solution Approach 2:
The implant enables change in critical parameters including vertebral body height, disc space height, and spinal alignment angles. By adjusting these parameters post-implantation, the surgeon can restore natural spinal balance without the need for fusion, thereby preventing chronic pain and adjacent segment degeneration
3Strength
If traditional pedicle screw fixation is used, then strong anchorage to the spine is achieved, but alignment with pedicles is difficult and requires precise pre-drilling
Solution Approach 1:
The pedicle fastener includes a polyaxial receiver that allows dynamic adjustment of screw orientation after insertion. The receiver can accommodate screws entering at various angles (up to 30 degrees in some embodiments), allowing surgeons to insert screws more easily without precise pre-drilling while still achieving strong anchorage through final tightening
Solution Approach 2:
The polyaxial receiver adds an angular dimension of freedom to the pedicle screw system. Instead of requiring precise alignment in a single plane, the device allows adjustment in multiple angular dimensions, significantly easing the alignment requirement while maintaining strong fixation through the expansion and locking mechanisms
Data Source
AI summary
A vertebral body system and method having a polyaxial fastener receiving member, adjustable width plates and a pedicle screw having a pedicle threaded portion and a threaded portion for fastening to the vertebral body.