Ratchet Collet Rod Reduction Instrument for Spinal Surgery
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Solution Overview
Problem
In orthopedic surgery, particularly spinal surgery, surgeons face difficulties in accessing and positioning spinal rods due to anatomical constraints and the need for precise force application, especially in minimally invasive procedures where direct access is limited, making manual rod reduction cumbersome and inefficient.
Innovation Solution
A rod reduction instrument featuring a ratchet collet mechanism with a reduction pawl and drive handle, allowing for ergonomic and intuitive rod positioning and securement within a polyaxial screw or other fasteners, reducing the need for direct manual force and enabling precise alignment and attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual force is applied directly to position the rod, then the rod can be positioned, but large applications of manual force are required and access is difficult
Solution Approach 1:
The patent introduces a rod reduction instrument as an intermediary device between the surgeon's hand and the rod. The instrument includes a ratchet collet mechanism that engages with the rod and provides mechanical advantage, allowing the surgeon to apply force indirectly through the instrument rather than directly to the rod, thereby reducing the effort required and improving ease of operation.
Solution Approach 2:
The instrument incorporates a ratchet mechanism that converts rotational motion into linear motion along the rod's axis. By adding this dimensional transformation, the surgeon can apply rotational force through the handle, which is easier to generate, and have it converted into the linear pushing force needed to position the rod, reducing the direct manual force requirement.
2Ease of operation
If direct access to the rod and fixation element is required, then rod positioning can be performed, but access is difficult in minimally invasive procedures
Solution Approach 1:
The rod reduction instrument serves as a mediator that can be introduced through smaller incisions. The instrument's design allows it to reach the rod and fixation element through a reduced access path, with the ratchet collet mechanism engaging the rod from a distance, thereby maintaining ease of operation while reducing the complexity of the surgical approach.
Solution Approach 2:
The instrument is divided into functional segments: a handle portion for force application, a shaft for transmission, and a ratchet collet mechanism for engagement. This segmentation allows each component to be optimized for its specific function, enabling the overall instrument to access the rod through smaller incisions while maintaining the capability to perform rod positioning.
3Manufacturing precision
If fine increment reduction is required, then precise positioning is achieved, but instrument profile increases
Solution Approach 1:
The ratchet mechanism provides continuous fine-adjustment capability through incremental tooth engagement. Each rotation of the handle advances the rod by a small, controlled amount determined by the ratchet tooth pitch, allowing precise positioning without requiring a complex multi-component adjustment system, thereby maintaining a compact instrument profile.
Solution Approach 2:
The ratchet tooth geometry and pitch are designed to provide optimal fine-adjustment parameters. By carefully selecting the tooth pitch and engagement angle, the instrument achieves precise rod positioning with a compact design, balancing positioning precision requirements with instrument size constraints.
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
Facilitates efficient and secure rod positioning and attachment with reduced manual effort, suitable for both open and minimally invasive surgeries, enhancing procedural efficiency and reducing surgical invasiveness.
Implementation Method 1
The actuating assembly is operable, upon actuation, to push the rod toward the implant
Implementation Method 2
The instrument includes a series of ratcheting mechanisms that reduces the need for large applications of manual force for rod positioning
Implementation Method 3
a spring in initial position, wherein the spring is biased toward the spring initial position
Data Source
AI summary
The invention encompasses instrumentation for rod reduction for use in orthopedic surgery that is ergonomic and intuitive to use. In certain embodiments, the invention encompasses a rod reducing instrument including a series of ratcheting mechanisms that reduces the need for large applications of manual force for rod positioning necessary during surgical procedures. The internalized mechanism also allows for a reduction in fine increments without an increase in surgical instrument profile or necessary force input. In certain embodiments, the instrument includes one or more channels to accept the locking delivery instrument further streamlining the surgical process. The rod reducing instrument of the invention refines the reduction process allowing for faster, stronger reduction, with a quick and effective release.