Adjustable-Height Fusion Cage for Endoscopic Bone Grafting
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Solution Overview
Problem
Conventional interbody cages with fixed sizes and limited adjustability pose challenges in minimally invasive spine surgery, leading to insufficient bone grafting and compromised fusion efficacy due to the difficulty in placing large cages and maintaining sufficient bone quantity within the intervertebral space.
Innovation Solution
A height-adjustable cage design with a novel structure and large opening at the tail, combined with a bone grafting tool, allows for easy expansion and filling of autologous and allogeneic bone into a spacious grafting chamber, ensuring adequate bone grafting and compatibility with endoscopic procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional fixed-size cages are used, then the structure is simple and easy to manufacture, but the cage cannot be adequately placed under endoscope channel and bone grafting space is insufficient
Solution Approach 1:
The cage employs a height-adjustable mechanism where the cage body can be compressed and expanded through a pushing assembly with threaded rod and U-shaped base. This dynamic structure allows the cage to be inserted in a compact state and then expanded to the required height, providing sufficient bone grafting space while maintaining reasonable structural complexity.
Solution Approach 2:
The cage is divided into multiple functional components including the cage body, cage support plate assembly, pushing assembly, and end cover. This segmentation allows each component to perform its specific function independently, enabling the overall system to achieve both compact insertability and expanded bone grafting capacity.
2Volume of moving object
If the cage height is increased to provide more bone grafting space, then the bone grafting capacity is improved, but the cage becomes difficult to place under endoscope channel
Solution Approach 1:
The cage utilizes a dynamic compression mechanism where the cage body is compressed to a smaller height for insertion under the endoscope channel, and then expanded to the required height for bone grafting after placement. This dynamic transformation resolves the contradiction between compact insertability and expanded functionality.
Solution Approach 2:
The cage is prepared in a pre-compressed state before insertion, allowing it to fit through the endoscope channel. After placement in the intervertebral space, the cage is then expanded to its full height to provide adequate bone grafting space. This preliminary preparation of the cage in a compact form enables both easy placement and sufficient bone grafting capacity.
3Volume of moving object
If the cage is expanded to high height for better intervertebral space maintenance, then the support function is improved, but the bone grafting chamber becomes larger and bone quantity becomes insufficient
Solution Approach 1:
The cage employs a dynamic height adjustment mechanism that allows the cage to be expanded to the required height for maintaining intervertebral space, while the design ensures that the bone grafting chamber volume is optimized to accommodate sufficient bone graft material. The pushing assembly enables controlled expansion to achieve the right balance between height and bone grafting capacity.
4Ease of operation
If a large opening is provided at the tail of the cage for bone grafting, then the ease of bone filling is improved, but the structural integrity may be compromised
Solution Approach 1:
The large opening is provided specifically at the tail end of the cage where it is most needed for bone grafting access, while the rest of the cage structure maintains its integrity. The opening section is strategically designed to provide easy bone filling access without compromising the overall structural strength of the cage body and support plates.
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 design facilitates accurate and efficient bone grafting, enhancing fusion efficacy by maximizing bone volume within the cage, while maintaining ease of operation and compatibility with endoscopic techniques.
Implementation Method 1
a screw section, a side section integrally connected to two ends of the screw section respectively, and an opening section integrally connected to the side section, where a threaded through-hole is provided on the screw section
Implementation Method 2
an end cover interference-fitted on one end face of the main body
Data Source
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AI summary
The present disclosure discloses a cage with an adjustable height with posterior bone grafting, comprising: a main body, a blade assembly fitted to the main body, and a pushing assembly fitted to the blade assembly, wherein an end cover is interference-fitted on one end face of the main body, the main body comprising a screw section, a side section integrally connected to two ends of the screw section respectively, and an opening section integrally connected to the side section, where a threaded through-hole is provided on the screw section, and an opening through-hole is provided on the opening section, the pushing assembly comprising a first U-shaped base and a threaded rod fixedly connected to the first U-shaped base, wherein the threaded rod passes through the first U-shaped base, and a pin is fixedly connected to an end, close to the threaded rod, of the first U-shaped base. According to the present disclosure, the structure is designed and operated conveniently, the damage to human body is minimized, the cage is expanded to reach the height of intervertebral space required by the patient, and the space of the bone grafting chamber of the cage is increased after the expansion, so as to meet the need of continuous bone grafting.