Adjustable SI Joint Fixation Screw and Wedging Cage Integration
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Solution Overview
Problem
Current SI joint fusion implants lack flexibility during surgical procedures, forcing surgeons to choose between screws or cages for fusion or fixation, limiting treatment options for SI joint pain.
Innovation Solution
The SI joint fixation system includes various shaped wedging cages (A-shaped, B-shaped, etc.) and screws, allowing for hybrid strategies such as fixation alone, fusion alone, or fixation plus fusion, with features like textured surfaces and 3D printing for enhanced bone integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional SI fusion implants (screws or cages) are used, then fixation or fusion can be achieved, but flexibility during surgical procedure is limited
Solution Approach 1:
The patent combines fixation screws and fusion cages into a single integrated implant system. The cage includes threaded bores that receive fixation screws, allowing both fixation and fusion functions to be performed by one implant rather than requiring separate screw and cage components. This merging provides surgical flexibility while managing system complexity.
Solution Approach 2:
The fusion cage is designed with multi-functionality to serve both as a structural spacer and as a fixation device. By incorporating threaded bores and receiving features for screws directly into the cage structure, the single implant can perform multiple functions (fixation, fusion, and spacing) that traditionally required separate components, thereby improving adaptability during surgery.
2Reliability
If fixation screws are used alone, then acute stabilization is achieved, but long-term fusion capability is limited
Solution Approach 1:
The fixation screws are pre-integrated into the cage structure through threaded bores, allowing the surgeon to first achieve acute stabilization with the screws, then subsequently perform fusion through the same cage. The cage is prepared in advance with receiving features that enable both immediate fixation and later fusion bone growth, ensuring both short-term and long-term success.
Solution Approach 2:
The patent merges the fixation function (screws) and fusion function (cage) into a single integrated system. The fixation screws provide acute stabilization while the cage structure provides the framework for long-term fusion bone growth. Both functions work together synergistically within one implant rather than as separate staged procedures.
3Ease of operation
If smooth cage surfaces are used, then implantation is easier, but bone integration is reduced
Solution Approach 1:
The cage is designed with different surface qualities in different locations. The outer surface that contacts bone includes textured regions with increased surface area and roughness to promote bone integration, while maintaining overall structural smoothness for ease of implantation. This local differentiation allows both easy implantation and strong bone integration to coexist.
Solution Approach 2:
The cage incorporates porous or textured surface regions that increase bone contact area and promote osteointegration. These porous or roughened areas provide anchoring points for bone growth while the overall cage structure remains smooth enough for straightforward implantation. The textured surfaces may include micro-roughness or porous coatings that enhance bone attachment.
Data Source
AI summary
The invention discloses an improved wedging cage within the sacroiliac (SI) joint and fixation screw(s). The wedging cage is adapted to be positioned between the sacrum and the lilac bone (e.g., the sacroiliac joint), and the wedging cage is effective to receive one or more fixation or axial screws to fasten the wedging cage and secure the wedging cage to the adjacent pelvic bones to provide a combination effect of fusion and/or fixation. Accordingly, the improved fixation screw assemblies promote flexibility and adaptability due to the adjustable head being movable to a locked and unlocked position relative to the screw body when implanted onto a substrate.