Dual-Diameter Guide Wire for Intramedullary Implant Delivery
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Solution Overview
Problem
Current treatments for small bone fractures, such as phalangeal and metacarpal fractures, often result in poor rotation control, delayed mobilization, prolonged stiffness, increased operative exposure, and postoperative complications like pin-site infections due to the use of off-the-shelf K-wires, which protrude from the bone surface.
Innovation Solution
A dual-diameter guide wire system is used to deliver intramedullary fixation implants that achieve bicortical purchase and anti-rotation, allowing for more accurate sizing and placement to ensure the implants are flush with the bone surface, reducing the risk of infection and displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If off-the-shelf K-wires are used for fracture fixation, then the procedure can be performed with standard equipment, but the K-wires protrude from the bone surface causing pin-site infections
Solution Approach 1:
The patent changes the geometric parameters of the guide wire by incorporating a stepped configuration with different diameters along its length. The first diameter portion is smaller than the second diameter portion, allowing the guide wire to be received within the medullary canal while having its proximal end extend through the cortical wall. This parameter change enables the guide wire to serve dual purposes: guiding implant placement and providing a flush surface that prevents protrusion and associated infections.
2Device complexity
If off-the-shelf K-wires are used, then no customization is needed, but accurate sizing and placement of implants is difficult
Solution Approach 1:
The guide wire incorporates variable diameter sections that correspond to different implant sizes. The stepped configuration allows the surgeon to select and insert the appropriate guide wire diameter based on the specific fracture location and bone anatomy. This enables precise sizing of the intramedullary implant while maintaining a relatively simple overall device structure that can be customized during the procedure.
Solution Approach 2:
The guide wire is segmented into distinct functional portions: a first diameter portion for receiving the implant, a second diameter portion for extending through the cortical wall, and a third diameter portion for engagement with the driver. This segmentation allows each portion to be optimized for its specific function while collectively providing accurate implant placement guidance.
3Stability of the object's composition
If cross-pinned K-wires are used to achieve bicortical purchase, then rotation control is improved, but the protruding ends increase infection risk
Solution Approach 1:
The guide wire uses a stepped diameter configuration where the second diameter portion extends through the cortical wall to provide bicortical purchase for rotation control, while the proximal end is designed to be flush with or recessed into the bone surface. This eliminates the protruding end problem while maintaining the rotational stability provided by cross-pinning.
4Productivity
If intramedullary fixation implants are used, then surgical time and recovery time are reduced, but accurate placement requires complex guidance systems
Solution Approach 1:
The patent extracts the guidance function from a separate complex navigation system and integrates it directly into the guide wire itself. The stepped guide wire provides built-in dimensional guidance through its varying diameters, eliminating the need for external imaging guidance systems or complex surgical instruments. This simplifies the overall system while maintaining high surgical efficiency.
Data Source
AI summary
A fracture treatment system can include a pair of implants cross-pinned into the medullary canal of a bone, guided by at least one guide wire with at least two diameters. The system allows for more accurate sizing of the length of implants needed to achieve bicortical purchase for enhanced stability, as well as anti-rotation of the fracture site. The more accurate sizing and placement of the cross-pinned implants additionally allow both ends of the implants to recess beneath or be flush with the outer surface of the bone, which can reduce the risk of infection. The guide wire can allow the implants to be inserted using a cannulated technique for easier surgical procedure and better outcome, with the implants having sufficient wall thickness for the desired length to achieve bicortical purchase while keeping the shaft outer diameter of the implant to be similar to a diameter of the guide wire.