Two-Piece Pedicle Anchor for Dynamic Spinal Stabilization
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Solution Overview
Problem
Conventional spinal instrumentation for vertebral stabilization, such as pedicle screws and rods, leads to complications like nerve injury, excessive bleeding, prolonged operative time, pedicle screw loosening, and accelerated degeneration of adjacent segments, while also compromising the natural flexibility of the spine.
Innovation Solution
A two-piece suspension pedicle anchor system with a proximal and distal piece, where the distal piece is fixed to the bone without rotation, and an artificial ligament is sandwiched between the anchor and bone, allowing dynamic stabilization through a translaminar pedicle anchor suspension system (T-PAS) that avoids traditional fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional pedicle screws and rods are used for vertebral stabilization, then immediate stability is achieved, but nerve injury, excessive bleeding, and prolonged operative time occur
Solution Approach 1:
The pedicle anchor is divided into two separate pieces: a proximal piece that engages with the bone and an artificial ligament that connects to the vertebral body. This segmentation allows the stabilizing function to be distributed across different structures, reducing the need for deep pedicle screw insertion and associated surgical risks.
Solution Approach 2:
An artificial ligament is introduced as an intermediary element between the pedicle anchor and the vertebral body. This ligament serves as a mediator that provides stabilization while avoiding direct rigid fixation, thereby reducing stress concentration and potential nerve injury during implantation.
2Stability of the object's composition
If conventional pedicle screws are used, then vertebral fixation is achieved, but pedicle screw loosening occurs over time
Solution Approach 1:
The system transitions from rigid fixed fixation to dynamic stabilization. The artificial ligament allows for controlled movement and flexibility while maintaining vertebral alignment, reducing stress shielding and preventing screw loosening through physiological load distribution.
3Stability of the object's composition
If rigid spinal instrumentation is used, then immediate stability is achieved, but natural flexibility of the spine is lost
Solution Approach 1:
The artificial ligament provides dynamic stabilization that allows physiological movement and flexibility of the spine while maintaining stability. Unlike rigid rods, the ligament can accommodate natural spinal motion, preserving adaptability and preventing adjacent segment degeneration.
4Stability of the object's composition
If conventional pedicle screws with rods are used, then vertebral stabilization is achieved, but bulky implant components cause soft tissue impingement and pain
Solution Approach 1:
The bulky rod component is extracted and replaced with a flexible artificial ligament. This eliminates the need for large implant components that impinge on soft tissues, reducing postoperative pain and complications while maintaining stabilization function.
Data Source
AI summary
A two-piece suspension pedicle anchor and its system and component-set is disclosed. The two-piece suspension pedicle anchor comprises a proximal piece and a distal piece that can rotate relatively. An external thread is arranged on the outer surface of the proximal piece, and a transverse through hole for an artificial ligament to pass through is arranged at the distal piece. As the two-piece suspension pedicle anchor is rotated and gradually locked into the bone, only the proximal piece is rotated, and the distal piece with the artificial ligament is pushed down but not rotated; in addition, the artificial ligament will be brought into the bone along with the distal piece and sandwiched between the outer surface of the proximal piece and the bone, that is, the artificial ligament will be sandwiched and fixed between the anchor-bone interface without wrapping around the outer surface of the proximal piece.