Shape Memory Bone Plate with Insertion Tool Constraint
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Solution Overview
Problem
Shape memory plates used in osteosynthesis face challenges in maintaining a superelastic state during implantation and surgery, as they tend to transform at room temperature, making implantation difficult, or require external heating, which can be unreliable during surgery.
Innovation Solution
A shape memory plate system that can be moved between an implantation shape and an insertion shape, with an insertion tool holding the plate in the insertion shape for secure anchoring to bones before transitioning to the implantation shape to create compression, using drill guide tubes and locating pins for precise placement and screw fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the plate is made superelastic to transform at room temperature, then the plate can transform without external heating, but the plate transforms immediately making implantation and screw attachment difficult
Solution Approach 1:
The plate is pre-formed in the desired final compressed configuration, then constrained in a transformed state for implantation. After securing to bone, the constraint is released allowing the plate to transform to its final shape, applying compression to the bone. This preliminary preparation resolves the contradiction by separating the transformation action from the implantation procedure.
Solution Approach 2:
A constraint mechanism acts as an intermediary between the plate's superelastic transformation tendency and the implantation process. The constraint prevents premature transformation during implantation and screw attachment, then releases to allow controlled transformation afterward. This intermediary resolves the contradiction by mediating between the plate's inherent transformation property and surgical operational requirements.
2Stability of the object's composition
If the plate is designed to transform at body temperature or with heating, then the plate remains stable during surgery, but external heating sources or body heat are unreliable during surgery
Solution Approach 1:
The plate's transformation temperature parameters are modified through material composition adjustments to enable transformation at room temperature rather than requiring body temperature or external heating. This parameter change resolves the contradiction by making the transformation reliable and controllable without depending on unreliable heating sources during surgery.
3Ease of manufacture
If the plate transforms immediately at room temperature, then no external heating is needed, but the compression occurs before proper bone anchoring
Solution Approach 1:
The plate is prepared in advance in a constrained state that prevents transformation. The constraint is designed to be easily applied during manufacturing or packaging, and removed or released during surgery after proper anchoring. This preliminary preparation resolves the contradiction by enabling simple activation while maintaining precise timing control through the constraint mechanism.
Solution Approach 2:
The constraint mechanism serves as an intermediary that decouples the plate's intrinsic transformation tendency from the timing of compression application. It allows the plate to maintain superelastic properties for simple activation while controlling when transformation occurs to ensure proper timing relative to bone anchoring.
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 secure and controlled compression between bones, allowing surgeons to manage the timing of compressive force application and facilitating complex surgeries by maintaining the plate in the insertion shape until properly anchored, thereby preventing premature transformation.
Implementation Method 1
Shape memory devices feature a martensitic and austenitic form, in which the addition of energy in the form of heat transforms the device from a temporary mart site state to a final austenite state at a defined temperature
Implementation Method 2
an apparatus and a method of surgical use for a shape memory plate that restrains the plate in an open position while screws are attached
Implementation Method 3
nickel-titanium and shape memory materials have been used in orthopedics for their shape changing and superelastic properties
Data Source
AI summary
An orthopedic bone plate constructed from shape memory material provides the ability to move from an open shape to a compressed shape and create compression on two bones or bone fragments to encourage healing. The plate may be any umber of shapes, with two or more screws anchoring the plate to bone. The plate is affixed to bone in a sequence of steps that involve first placing the plate on an insertion tool, attaching drill guide tubes, placing the plate over bone, drilling holes in bone, and then attaching the plate to the bone via screws. The insertion tool can then be removed at the surgeon's convenience allowing compression on the two bones.