Articulating Disc Cutter for Minimally Invasive Endplate Preparation
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Solution Overview
Problem
Existing minimally invasive spinal surgery techniques face challenges in efficiently removing intervertebral discs due to limited access and difficulty in visualizing and preparing the vertebral endplates, often requiring manual tools that can cause damage to surrounding tissues and prolong recovery times.
Innovation Solution
A powered disc cutter apparatus with an articulating cutting tip, driven by a handheld motor, is designed for insertion through a narrow access port, allowing rotation and articulation up to 80°/90° to efficiently remove disc material and prepare the vertebral endplates, utilizing a flexible nitinol shaft and linkage mechanism for controlled motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If manual tools are used for disc removal, then surgical skill and care can avoid damage to surrounding tissues, but the procedure is time-consuming and difficult to perform within smaller access spaces
Solution Approach 1:
The patent replaces manual mechanical tools with a powered cutting assembly that uses motorized rotation (up to 30,000 RPM) to perform disc removal. This substitution eliminates the need for manual manipulation while maintaining precision through controlled mechanical motion, thereby improving surgical efficiency without increasing tissue damage.
Solution Approach 2:
The cutting assembly is designed with dynamic capabilities including rotation about its long axis and articulation up to 80-90 degrees from the longitudinal axis. This dynamic design allows the tool to adapt to the limited access window and navigate the intervertebral space effectively, improving productivity within constrained surgical environments.
2Productivity
If powered tools are used to ease the procedure and reduce recovery time, then surgical time is reduced, but the risk of damage to surrounding tissues increases
Solution Approach 1:
The cutting assembly utilizes a flexible nitinol shaft that allows articulation and bending within the constrained access port. This flexibility enables the powered tool to navigate the intervertebral space and reach the disc material without exerting excessive force on surrounding tissues, thereby maintaining high surgical speed while minimizing tissue damage.
Solution Approach 2:
The cutting assembly is divided into modular components including a rotatable cutting element, articulating sections, and a flexible shaft. This segmentation allows independent control of each component, enabling precise positioning and controlled cutting action that reduces the risk of unintended tissue damage while maintaining efficient disc removal.
3Ease of operation
If a narrow access port is used to minimize incision size, then patient recovery is improved, but visualization and evaluation of disc removal quality becomes very difficult
Solution Approach 1:
The patent incorporates an illumination system as an intermediary element within the cutting assembly. This illumination source provides direct lighting at the disc removal site, enabling the surgeon to visualize the quality of disc removal and endplate preparation through the narrow access port, thereby maintaining minimally invasive access while overcoming visualization limitations.
4Adaptability or versatility
If the cutting assembly can articulate up to 80-90 degrees to reach across the intervertebral space, then access to the disc is improved, but the device complexity increases
Solution Approach 1:
The patent employs a flexible nitinol shaft as the basis for articulation, which inherently provides the necessary degrees of freedom through its superelastic properties. This approach achieves 80-90 degree articulation capability without requiring complex mechanical joints or actuators, thereby maintaining adaptability while controlling device complexity.
Solution Approach 2:
The flexible nitinol shaft utilizes its own material properties (superelasticity and memory effect) to provide articulation and return to its original configuration. This self-service mechanism eliminates the need for additional actuators or complex control systems, achieving high adaptability with simplified device architecture.
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 disc removal and endplate preparation within minimal access spaces, reducing surgical time and tissue damage, and enabling safer, more precise procedures with faster recovery.
Implementation Method 1
The tip, along with articulating drive components, is constrained together by crimping caps onto both ends of, for example, a super-elastic nitinol shaft that goes through the center of the components. The nitinol is flexible enough to allow the full articulation and rotation of the cutter.
Implementation Method 2
The nitinol is pre-biased or memory shaped such that it biases toward a bend.
Data Source
AI summary
An apparatus for use in preparing the intervertebral disc space. The apparatus includes a powered disc cutter that can be inserted through a tube and into the disc space. Once inside the disc space, the cutter can be rotated on its axis and articulated through the disc space to break up and disconnect the disc tissue from the surrounding disc tissue and disc annulus. The device is powered by a handheld driver that utilizes a motor to impart motion, such as rotary motion, to an elongated shaft assembly having a cutting tool or assembly pivotably attached to the distal end thereof. The cutting tool is mounted to the end of the drive shaft assembly by a linkage so that the shaft may be inserted in a straight configuration down a narrow access port. The cutting assembly can spin on its axis while being articulated providing access to the intervertebral space.