Reducer Handle Locking at the Pivot for Clear Rod Reduction
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Solution Overview
Problem
Current rod reduction instruments in spinal fixation procedures face challenges such as binding due to misalignment, obstructed visibility, difficulty in determining rod reduction completion, and complex manufacturing of ratchet locks, which hinder workflow and usability.
Innovation Solution
A locking mechanism for reducer instruments with a pawl or latch adjacent to the center pivot joint, eliminating the need for a large ratchet at the proximal end, providing auditory and tactile feedback for sufficient reduction and allowing easy release with a button.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large and long ratchet with multiple teeth is used at the proximal end of the opposed handles, then the locking mechanism can maintain the handles in position, but it becomes prone to binding due to misalignment and obscures the surgeon's view
Solution Approach 1:
The patent removes the traditional large ratchet mechanism from the proximal end of the handles and replaces it with a compact locking mechanism located at the pivot joint. This extraction of the harmful element (large ratchet) eliminates the binding and visibility problems while maintaining the essential locking function through a different mechanism (pawl and groove engagement).
Solution Approach 2:
The locking mechanism is relocated from the proximal end of the handles (one-dimensional positioning) to the pivot joint area (different spatial dimension). This dimensional change allows the locking mechanism to engage at the point of rotation, providing effective locking without the space-consuming proximal ratchet structure that caused binding and obscured view.
2Reliability
If multiple ratchet teeth are used, then the locking mechanism can maintain handle position, but it becomes difficult to determine when the rod is sufficiently reduced for set screw insertion
Solution Approach 1:
The patent incorporates a visual feedback mechanism where the pawl's engagement with the groove provides clear indication of the locked position. The surgeon can visually confirm when the rod is sufficiently reduced by observing the pawl-groove engagement, eliminating the ambiguity of multiple ratchet teeth and providing definitive information about reduction completion.
Solution Approach 2:
The patent employs visual indicators (such as colored markings or transparent sections) that change or become visible when the pawl engages the groove, providing immediate visual feedback to the surgeon about the locking status and rod reduction completion, replacing the indistinct multiple-tooth ratchet system.
3Reliability
If a ratchet lock with multiple teeth is used, then the locking mechanism can maintain handle position, but it becomes difficult to disengage as teeth can catch and prevent continued removal
Solution Approach 1:
The patent employs a dynamic release mechanism where a button or actuator allows the pawl to disengage from the groove on demand. This dynamic element transforms the static, difficult-to-disengage ratchet teeth system into a controllable locking mechanism that can be easily released when needed, while maintaining reliable locking during use.
4Reliability
If a large ratchet is disposed at the proximal end of the device, then the locking function is achieved, but it interferes with gripping and actuation of the instrument
Solution Approach 1:
The locking mechanism is relocated from the proximal grip area to the pivot joint region, changing its spatial dimension and position. This relocation eliminates interference with the surgeon's grip and actuation of the instrument handles while preserving the essential locking function at the mechanical pivot point where it is most effective.
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
Enhances workflow efficiency, improves usability by ensuring clear visibility and easy set screw insertion, and simplifies manufacturing with a more straightforward design.
Implementation Method 1
a pawl pivotably coupled to the second handle distal to the grip portion, the pawl being configured to ride over a portion of the housing that includes a groove as the second handle is moved toward the first handle; wherein the pawl is configured to seat in the groove and maintain a relative position of the first and second handles
Data Source
AI summary
Disclosed are reducer instrument locking mechanisms. They can be located near a center pivot joint of the reducer, thereby eliminating a ratchet at the reducer proximal end. The locking mechanisms can include a pawl or latch that travels with one handle from an open position to a closed position. The pawl can fall into a groove formed in an opposing handle such that handles of the reducer can be locked relative to one another, at least with regard to movement of the handles away from one another. When falling into the groove, the pawl can create an auditory and/or tactile indication that a sufficient amount of rod reduction has been achieved to allow for set screw insertion. After set screw insertion, the reducer locking mechanisms can be released to clear it of the groove and allow the reducer to return to its open position.