Pedicle Screw Assembly with Exposed Neck for Depth Control
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Solution Overview
Problem
Existing pedicle screw fixation systems in orthopedic surgery face challenges in accurately determining the depth of screw implantation, leading to potential damage to blood vessels or inadequate fixation strength due to the integration of screw seats and bodies, which complicates surgical procedures and increases risks of bleeding and infection.
Innovation Solution
A pedicle screw assembly where the screw and screw seat are separated, allowing the screw to be implanted first, then snapped into a connecting claw for assembly, enabling clear visualization and adjustable fixation modes between dynamic and static configurations, with an installation tool facilitating precise placement and adjustable fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the screw seat and screw body are integrated before operation, then the structure is simplified, but it becomes difficult to accurately judge implantation depth and increases surgical risks
Solution Approach 1:
The pedicle screw system is divided into separate components: a screw body for implantation and a screw seat for fixation. The screw body can be implanted first with its neck exposed for depth observation, while the screw seat is attached afterward. This segmentation allows accurate depth judgment during implantation while maintaining structural integrity through the connecting rod and locking mechanism.
2Strength
If the screw is implanted deeply to ensure fixation strength, then fixation strength is improved, but it may penetrate the front edge of the spine and endanger blood vessels
Solution Approach 1:
The exposed neck of the screw body serves as a visual feedback mechanism during implantation. The surgeon can directly observe the implantation depth through the exposed neck, providing real-time feedback to prevent over-implantation that could endanger blood vessels, while ensuring adequate depth for fixation strength.
3Object-affected harmful factors
If the screw is implanted shallowly to avoid vascular injury, then safety is improved, but fixation strength becomes inadequate
Solution Approach 1:
By separating the screw body implantation from the screw seat attachment, the system allows optimal implantation depth to be achieved for safety, while the subsequently attached screw seat and connecting rod provide the necessary fixation strength. The exposed neck enables depth control, and the separate screw seat ensures adequate fixation without requiring excessive implantation depth.
4Adaptability or versatility
If the screw seat is large-sized to accommodate dynamic fixation components, then dynamic fixation capability is improved, but it covers the screw neck and makes observation difficult
Solution Approach 1:
The system separates the screw body (with exposed neck for observation) from the screw seat (which provides dynamic fixation capability). This allows the screw neck to remain visible during implantation for depth assessment, while the screw seat can be designed with larger dimensions to accommodate dynamic fixation components without interfering with observation.
5Measurement precision
If the pedicle screw is dismantled to adjust implantation depth, then implantation depth can be corrected, but operation time is prolonged and risk of bleeding and infection increases
Solution Approach 1:
The screw body is implanted first with its neck exposed for depth observation, allowing accurate depth assessment before the screw seat is attached. This preliminary action enables depth correction if needed before final assembly, avoiding the need to dismantle the complete assembly and reducing operation time and surgical risks.
6Measurement precision
If the pedicle screw is unscrewed to adjust depth, then implantation depth can be corrected, but fixation strength of screw track is greatly reduced
Solution Approach 1:
By separating the screw body from the screw seat, the system allows depth adjustment of the screw body without unscrewing it from the bone. The exposed neck enables depth assessment, and if adjustment is needed, only the unthreaded screw body needs to be repositioned, preserving the screw track fixation strength while correcting implantation depth.
Data Source
AI summary
There is provided a pedicle screw assembly for dynamic and static fixation, which is able to be assembled during the operation and allows a doctor to make an emergency choice between fusion fixation and non-fusion fixation. The pedicle screw assembly is used for inner fixation in spine surgery. During the operation, a pedicle screw is firstly implanted in a pedicle, and then a spherical head of the pedicle screw is enclosed by a connecting claw. After a screw seat is connected to the connecting claw by means of threads, a connecting rod is inserted in a groove and finally a locking screw is tightened to complete the fixation.