Spinal Implant Insertion Tool Cam Lock Mechanism
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Solution Overview
Problem
Existing insertion tool assemblies for spinal implants face challenges in securely holding and maneuvering implants within the patient without causing damage to surrounding structures, and they often experience issues with cross-threading and maintaining parallelism with artificial discs.
Innovation Solution
The proposed insertion tool assembly includes an outer shaft with a proximal and distal section, an inner shaft with angled ramps, and a pair of arms that move laterally to engage and disengage the implant. This design ensures secure fixation and release of the implant during insertion and maneuvering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded connections are used to secure the implant to the holder, then the implant can be firmly fixed, but cross-threading occurs and difficulties arise in placing the implant in the desired position
Solution Approach 1:
The patent replaces the threaded mechanical connection system with a cam-based locking mechanism. The cam lock engages with the implant holder through a cam surface that converts rotational motion into linear clamping force, eliminating cross-threading issues while maintaining secure fixation. The cam mechanism allows for smooth engagement and disengagement without the threading problems that plague traditional threaded connections.
2Strength
If parallel vertical jaws are used to secure the implant, then the implant can be held, but the jaws have issues maintaining parallelism with regards to the upper and lower endplates in certain artificial discs
Solution Approach 1:
The patent employs a dynamic jaw mechanism that can adapt its orientation to match the implant's geometry. The jaws are mounted on articulated arms that allow them to pivot and adjust their angle relative to the implant endplates. This dynamic adjustment capability enables the jaws to maintain proper parallelism with non-parallel endplates, solving the precision issue while retaining holding strength.
Solution Approach 2:
The patent changes the geometric parameters of the jaw-implant interface by allowing the jaws to rotate and adjust their angular orientation. This parameter adjustment enables the jaws to conform to various endplate angles and geometries, maintaining both secure holding and proper parallelism alignment that rigid fixed jaws cannot achieve.
3Reliability
If the implant is securely fixed to the insertion tool assembly, then the implant can be maneuvered without articulation, but the implant should be readily removed once placed in the desired location
Solution Approach 1:
The patent incorporates a release mechanism that pre-prepares for the future need to detach the implant. The cam lock system includes a release lever or button that, when actuated, reverses the locking action. This preliminary anti-action design allows the surgeon to quickly and easily release the implant with a simple motion after secure fixation has been established during insertion, satisfying both secure holding and easy release requirements.
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 insertion tool assembly effectively secures the implant during impaction and maneuvering, preventing articulation and ensuring precise placement within the patient, while also facilitating easy release once the implant is in position.
Implementation Method 1
The inner shaft has angled ramps engaged with complementary angled ramps of the arms such that translation of the inner shaft along the longitudinal axis causes the angled ramps to slide against the complementary angled ramps of the arms, which in turn, causes the arms to move linearly and laterally
Data Source
AI summary
An implant insertion tool includes an outer shaft, an inner shaft received in the outer shaft, and two arms coupled to the outer shaft and the inner shaft. The inner shaft translates within the outer shaft and has angled ramps that slide within complementary angled ramps in the two arms. The arms engage an implant for insertion into a body. When the inner shaft translates along a longitudinal axis, it causes the angled ramps to slide against the complementary angled ramps in the arms such that the two arms move laterally relative to the longitudinal axis of the outer shaft to engage and disengage the implant.