Non-circular Cross-section Sacroiliac Joint Decortication System
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Solution Overview
Problem
Current sacroiliac joint fusion procedures often require invasive methods, leading to significant trauma and prolonged healing times, and may result in implant failure due to rotation and loosening, especially in joints subjected to torsional forces.
Innovation Solution
A system and method for decorticating bone surfaces using an elongated soft tissue protector and a cutter with a non-circular cross-section, allowing for minimally invasive joint preparation and stabilization through the placement of implants with a rectilinear or triangular cross-sectional profile, reducing the need for extensive soft tissue dissection and promoting faster fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open surgical approach with large incision and deep soft tissue dissection is used to approach the SI-Joint, then the surgeon can directly access the damaged joint for debridement and implant placement, but the patient experiences significant trauma and prolonged healing time
Solution Approach 1:
A guide wire and cannulated reamer are used as intermediary tools to create a controlled access path through the ilium to the SI-Joint. This allows the surgeon to reach the joint space without making a large incision or performing deep soft tissue dissection, thereby reducing soft tissue trauma while maintaining direct access to the joint for debridement and implant placement
Solution Approach 2:
The surgical approach is segmented into distinct steps: first inserting a guide wire through a small incision, then using a cannulated reamer to create a channel, followed by insertion of specialized instruments through the same channel. This segmentation allows minimally invasive access while maintaining the ability to perform all necessary joint preparation procedures
2Ease of manufacture
If traditional cylindrical implants are used in the SI-Joint, then implant placement is straightforward, but the implants are susceptible to rotation and loosening under torsional forces
Solution Approach 1:
The implant is designed with an asymmetric non-circular cross-section (rectangular, triangular, or oval) instead of a traditional cylindrical shape. This asymmetric geometry provides inherent resistance to rotation under torsional forces while maintaining relatively straightforward placement through a prepared channel. The asymmetric shape creates geometric interlocking with the bone, preventing rotational movement and loosening
Solution Approach 2:
The implant features a curved or angled entry portion that follows the natural trajectory of the ilium and SI-Joint anatomy. This curved design facilitates easier insertion through the bone while the distal portion maintains the asymmetric non-circular cross-section for rotational stability, combining ease of placement with long-term reliability
3Productivity
If no debridement or decortication of the articular surfaces is performed, then the surgical procedure is simpler and faster, but fusion of the joint may be slower and weaker
Solution Approach 1:
A specialized decortication instrument with a cutting blade is used as an intermediary tool to remove cartilage and expose the underlying cancellous bone through the same cannulated channel. This allows thorough debridement of the articular surfaces to promote strong fusion while maintaining the minimally invasive approach and avoiding the need for open surgery, thus preserving surgical efficiency
Solution Approach 2:
The decortication step is performed as a preliminary action before final implant placement. By removing the cartilage layer and exposing the vascular cancellous bone in advance, the surgeon creates optimal conditions for rapid and strong fusion. This preliminary preparation ensures that when the implant is placed, the bone surfaces are already ready for immediate bonding, accelerating the fusion process
Data Source
AI summary
A system for decorticating at least one bone surface includes an elongated soft tissue protector, an elongated drive shaft and a cutter. The elongated soft tissue protector has a bore extending therethrough. The bore has a non-circular lateral cross-section, a maximum lateral extent and a minimum lateral extent. The cutter may be located on or near a distal end of the drive shaft. The cutter has a non-circular lateral cross-section, a maximum lateral extent and a minimum lateral extent. The maximum lateral extent of the cutter is greater than the minimum lateral extent of the bore but is no greater than the maximum lateral extent of the bore. The bore of the soft tissue protector is configured to slidably receive the cutter therethrough. Other systems and methods for decorticating at least one bone surface are also provided.