Tissue Fixation Device with Drill Pin Delivery
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Solution Overview
Problem
Conventional tissue fixation devices for ligament reconstruction, such as those used for ACL and PCL repairs, often require substantial bone removal and have issues with delivery due to size and fragility, leading to complications and prolonged surgery.
Innovation Solution
A system featuring a tissue fixation device with elongate, rigid support members connected by flexible members, allowing for a delivery configuration with reduced dimensions to pass through smaller bone tunnels, and a drill pin to seat and deploy the device, facilitating easier implantation and reducing bone removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional cortical button fixation device is used, then the device can secure the ligament graft to bone, but the device requires substantial bone removal to drill a tunnel sized to receive the device
Solution Approach 1:
The tissue fixation device transitions from a compressed delivery configuration to an expanded deployed configuration. The flexible member allows the rigid support members to be close together during delivery, then separates them upon deployment to engage the bone surface, providing fixation strength without requiring a large bone tunnel
Solution Approach 2:
The device changes its physical dimensions through the transition from delivery to deployed configuration. The flexible member enables the device to compress to a smaller size for delivery through small bone tunnels, then expand to a larger size for fixation, effectively changing the size parameter to resolve the contradiction between small tunnel requirement and large fixation footprint
2Strength
If the tissue fixation device is made rigid for structural integrity, then the device can maintain shape and strength, but the device cannot be delivered through small bone tunnels
Solution Approach 1:
The device incorporates both rigid support members for structural integrity and a flexible member for dimensional adaptability. The flexible member allows the device to dynamically change its overall dimensions during delivery and deployment, while the rigid support members maintain their shape and strength throughout the process
Solution Approach 2:
The device is divided into separate functional components: rigid support members that provide structural integrity and engagement surfaces, and a flexible member that provides dimensional adaptability. This segmentation allows each component to optimize its properties without compromise
3Ease of operation
If leading sutures are used to deliver the tissue fixation device, then the device can be pulled through the bone tunnel, but the sutures may break during delivery
Solution Approach 1:
The drill pin serves as an intermediary delivery mechanism that directly engages and pulls the tissue fixation device through the bone tunnel, eliminating the need for leading sutures. The drill pin's threaded engagement with the device provides reliable force transmission without the fragility of sutures
4Ease of operation
If the tissue fixation device is delivered through a standard delivery system, then the device can be implanted, but the device may catch on the bone tunnel edge and become embedded in bone
Solution Approach 1:
The drill pin acts as a controlled intermediary that guides the tissue fixation device through the bone tunnel. The threaded engagement between the drill pin and device, combined with the gradual unscrewing action, provides precise control over device emergence from the tunnel, preventing erratic movement and bone embedding
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
Systems for fixating a graft in a bone tunnel are provided. In general, the system includes a tissue fixation device (1800) having a delivery configuration and a deployed configuration, at least one graft retention loop (1808) coupled to the tissue fixation device, and a drill pin (700) having a sidewall (706) surrounding a cavity (704) at a proximal end (702) of the pin and at least one longitudinally oriented opening (708) in the sidewall in communication with the cavity, the cavity being configured to fully seat the tissue fixation device (1800). The drill pin (700) is configured to substantially contain therein the tissue fixation device when in the delivery configuration and to enable deployment of the tissue fixation device through the opening. Drill pins configured to contain a tissue fixation device are also provided.