Surgical Locking Cap Dispensing with Splined Ratchet Control
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Solution Overview
Problem
Existing methods for securing bone screws using locking caps are inefficient and prone to errors, particularly with threaded caps that can cross-thread or accidentally disengage, leading to increased installation time and potential complications.
Innovation Solution
A dispensing tool with a magazine, splined guide bore, and ratchet mechanism that allows controlled dispensing and secure fitting of non-threaded locking caps, ensuring accurate and rapid installation by preventing backward movement and enabling rotational engagement with yokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded locking caps are used to secure bone screws, then the connection strength is improved, but the risk of cross-threading and accidental disengagement increases
Solution Approach 1:
The patent removes the threaded engagement feature from the locking cap design, extracting the problematic threading mechanism that causes cross-threading and accidental disengagement. The locking cap is designed as a non-threaded component that secures the bone screw through a different mechanism, eliminating the harmful threading interactions while maintaining connection strength.
Solution Approach 2:
Instead of using threaded engagement to secure the locking cap to the bone screw, the patent inverts the approach by using a non-threaded retention mechanism. The locking cap is retained on the bone screw through a friction fit or interference fit, reversing the conventional threaded engagement paradigm to eliminate cross-threading risks.
2Manufacturing precision
If manual installation of locking caps is performed, then the precision of installation is improved, but the installation time increases
Solution Approach 1:
The locking caps are pre-loaded into a magazine in the correct sequence and orientation before the surgical procedure. This preliminary arrangement eliminates the need for manual selection and positioning of individual caps during installation, maintaining precision while significantly reducing installation time through rapid sequential dispensing.
Solution Approach 2:
The device incorporates an automatic dispensing mechanism that sequentially delivers locking caps to the bone screw without requiring manual intervention for each cap. The system serves itself by automatically managing the inventory and positioning of multiple locking caps, maintaining installation precision while eliminating the time-consuming manual handling process.
3Adaptability or versatility
If multiple locking caps are carried and installed manually, then the versatility of the system is improved, but the complexity of operation increases
Solution Approach 1:
Multiple locking caps are merged into a single integrated magazine component, allowing multiple caps to be carried and managed as one unit. This consolidation eliminates the complexity of handling multiple separate caps, while the magazine's sequential dispensing mechanism maintains the versatility of using different cap types for different bone screw configurations.
Solution Approach 2:
The magazine is designed as a universal holding and dispensing mechanism that accommodates multiple locking cap types and configurations. This multi-functional component serves as both storage and delivery system, simplifying the operation of carrying and installing multiple caps while maintaining the system's adaptability to various surgical needs.
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
The tool enables efficient and error-free installation of locking caps, reducing procedural time and tissue damage by allowing quick, secure attachment of bone screws, thereby enhancing surgical efficiency and reducing complications.
Implementation Method 1
a biasing element connected between the support and the shaft, the biasing element configured to urge the shaft along the longitudinal axis in a direction towards the distal end
Implementation Method 2
a ratchet connected to the shaft and engageable with the magazine to permit sliding of the shaft in first a direction towards the distal end, to prevent sliding of the shaft in a second direction away from the distal end
Implementation Method 3
the shaft having an external surface mateable with the splined guide bore to restrict radial rotation of the shaft with respect to the support about the longitudinal axis
Data Source
AI summary
A surgical instrument enables dispensing of a series of fasteners within a patient's body. The device includes a magazine sized and dimensioned to hold a series of fasteners, the series of fasteners insertable through an opening at the end of the magazine. A splined guide bore is rotatably supported within the magazine, and slidingly supports a shaft having an external surface mateable with the splined guide bore to restrict radial rotation of the shaft with respect to the support about said longitudinal axis. A biasing element is connected between the support and the shaft, to urge the shaft along a longitudinal axis towards a distal end of the instrument. A ratchet is connected to the shaft and engages the magazine to permit sliding of the shaft in a direction for dispensing fasteners only, unless disengaged with the magazine.