Liquefiable Suture Anchor for Bone Tissue
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Solution Overview
Problem
Existing suture anchoring methods in bone tissue are limited by their reliance on specific bone qualities and mechanical properties, requiring multiple anchors for varying conditions and lacking versatility in minimally-invasive surgery applications.
Innovation Solution
A device utilizing liquefiable material by mechanical vibrations to create a strong connection between anchor parts and tissue, allowing for adjustable anchoring strength and applicability across different tissue types, with a sonotrode and guide sleeve system for precise control and minimal tissue stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screw-shaped anchors are inserted into bore holes through cortical bone, then anchoring is achieved in bone tissue, but the hold relies primarily on cortical bone and is not suitable for cancellous bone with low mechanical stability
Solution Approach 1:
The anchor changes its geometric parameters dynamically during insertion. The compression element transitions from a compressed state during insertion to an expanded state after insertion, changing the anchor's volume and surface area to adapt to different bone qualities and achieve reliable anchoring in both cortical and cancellous bone.
Solution Approach 2:
The anchor employs a dynamic compression element that can change its state during the anchoring process. The element is compressed during insertion through the cortical bone and then expands after insertion into the cancellous bone, allowing the anchor to adapt to varying bone densities and mechanical properties.
2Reliability
If radially compressible anchors with deformable barbs are impacted into bone tissue, then anchoring is achieved in cancellous bone, but the procedure requires impacting through pre-drilled bores and cannot be performed with minimal invasiveness
Solution Approach 1:
The invention replaces the impacting mechanism with a controlled expansion mechanism. Instead of mechanically impacting the anchor through a pre-drilled bore, the compression element is gradually expanded using a controlled force applied through the insertion device, reducing mechanical trauma to the bone tissue while achieving reliable anchoring.
Solution Approach 2:
The anchor is pre-compressed in a compact state before insertion, allowing it to be introduced through a small incision without requiring a large pre-drilled bore. After insertion, the compression element is gradually expanded to achieve anchoring, eliminating the need for extensive pre-preparation of the bone tissue.
3Reliability
If anchors are turned approximately 90 degrees after insertion, then anchoring in cortical bone is achieved, but the anchor must be longer than wide and cannot be extracted through the pre-drilled opening
Solution Approach 1:
The anchor maintains a consistent orientation during insertion and achieves anchoring through dynamic expansion of the compression element rather than rotational movement. This eliminates the need for the anchor to be longer than wide and for complex rotational maneuvers after insertion, simplifying both the anchor geometry and the insertion procedure.
Solution Approach 2:
The complex rotational step and the requirement for the anchor to be longer than wide are eliminated from the procedure. The anchor achieves cortical bone anchoring directly through controlled expansion of the compression element, removing unnecessary geometric constraints and procedural steps.
4Reliability
If anchors are designed for specific anchorage locations and bone qualities, then anchoring strength is optimized for those conditions, but multiple types of anchors must be selected and used for a single operation
Solution Approach 1:
The anchor is designed as a universal device that can adapt to different bone qualities and anchorage locations. The compression element can be controlled to expand to different degrees and in different patterns, allowing the same anchor design to achieve optimized anchoring strength in both cortical and cancellous bone, eliminating the need to select different anchor types for different conditions.
Solution Approach 2:
The anchor employs dynamic control of the compression element's expansion, allowing the surgeon to adjust the anchoring characteristics during the procedure. By controlling the degree and pattern of expansion, the same anchor can be optimized for different bone densities and locations, providing both specialized performance and universal applicability.
5Object-affected harmful factors
If the suture is attached to the anchor near the bone surface, then tissue cutting is minimized, but the anchor must not protrude above the bone surface and the eyelet design is constrained
Solution Approach 1:
The eyelet is integrated into the anchor structure in a nested configuration, with the suture attachment feature built into the anchor body itself. This eliminates the need for separate protruding eyelets and allows the suture to be attached near the bone surface without requiring the anchor to protrude above the bone, minimizing tissue cutting while maintaining design flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables robust and versatile suture anchoring independent of tissue mechanical properties, facilitating single-handed use in minimally-invasive procedures with adjustable anchoring depth and strength, suitable for diverse tissue types including bone with varying stability.
Implementation Method 1
The disclosed procedures rely on the liquefaction of a thermoplastic material via the application of mechanical vibrations, for instance ultrasonic vibrations
Implementation Method 2
liquefaction of a thermoplastic material via the application of mechanical vibrations
Implementation Method 3
for such liquefaction, friction between the bone tissue and the thermoplastic material and therewith a minimal mechanical strength of the tissue is needed
Data Source
AI summary
A device for the anchoring of a suture in tissue includes a guide sleeve, a sonotrode, an anchor and the suture. The guide sleeve has a distal part with a smaller cross section and a proximal part with a larger cross section. The sonotrode extends through the lumen of the guide sleeve and has a distal end and a proximal end, the proximal end being designed for coupling the sonotrode to a vibration source (e.g. an ultrasonic device). The anchor is arranged at the distal end of the device and includes an anchor foot and an anchoring sleeve sitting on a shoulder of the anchor foot. The anchoring sleeve consists of a material which is liquefiable through mechanical vibrations. A middle portion of the suture runs through the anchor foot and two end portions of the suture are attached to the guide sleeve.