Minimally Invasive Lumbar Bone Screw with Segmented Alignment Casing
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Solution Overview
Problem
Conventional bone screws used in minimally invasive spinal fixation devices are prone to breaking or deformation under external forces during surgery, and their complex structure increases the complexity and risk of the procedure, while alignment fixtures struggle to accurately conform to the spine's curvature due to structural limitations.
Innovation Solution
A bone screw design featuring a cup-shaped positioning casing with a rod securing base and alignment portion, including annular and longitudinal notches for easy separation, and a screw body with a spherical head and acute-tipped screw rod for secure fixation, allowing for accurate alignment and reduced surgical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bone screw structure is used with an upper portion and thread body, then the bone screw can be implanted into vertebras, but the structure is prone to breaking or deformation under external forces during surgery
Solution Approach 1:
The bone screw is divided into two functional segments: a positioning casing that provides structural support and alignment, and a screw body that provides fixation. This segmentation allows each component to be optimized for its specific function, preventing breaking while maintaining stability.
Solution Approach 2:
The positioning casing acts as an intermediary structure between the external environment and the screw body. It provides a protective and alignment function that prevents direct external forces from reaching the screw body, reducing the risk of breaking or deformation.
2Measurement precision
If a complex bone screw structure with caps and alignment fixtures is used, then alignment accuracy can be improved, but the surgical complexity and risk increase
Solution Approach 1:
The positioning and alignment functions are merged into a single integrated positioning casing structure. This eliminates the need for separate caps and alignment fixtures, simplifying the surgical procedure while maintaining alignment accuracy through the built-in alignment portion with openings for alignment tools.
Solution Approach 2:
The positioning casing serves multiple functions simultaneously: it provides structural support, enables alignment through its alignment portion, and facilitates rod securing through its rod securing base. This multi-functionality reduces the number of separate components needed, thereby reducing surgical complexity.
3Measurement precision
If a bone screw design with exposed alignment portion is used, then alignment accuracy with spine curvature is improved, but the risk of deformation under external force increases
Solution Approach 1:
The bone screw is segmented into a positioning casing with an exposed alignment portion and a screw body. The alignment portion can be exposed for accurate alignment with spine curvature while the screw body remains protected, preventing deformation under external forces during implantation.
Solution Approach 2:
The positioning casing is designed with a pre-exposed alignment portion that allows alignment operations to be performed before final fixation. This preliminary alignment action ensures accurate positioning with spine curvature while the protective structure of the positioning casing prevents deformation during the alignment process.
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 enhances the accuracy and efficiency of bone screw placement, simplifies the surgical process, and reduces the risk of deformation, enabling better alignment with the spine's curvature and faster assembly, thus improving the overall outcome of minimally invasive spinal fixation surgeries.
Implementation Method 1
The thread body extends from a first end of the upper portion and is configured to engage one of the vertebras
Implementation Method 2
the spherical head is configured with a joint notch corresponding to the shape of a driving tool and a non-slip texture for increasing the frictional force on the outer surface of the spherical head
Implementation Method 3
the screw rod being configured with an outer thread, and the front portion of the screw rod having a tip with an acute angle
Data Source
AI summary
A bone screw of minimally invasive fixation device for lumbar comprises a positioning casing and a screw body. The positioning casing includes a rod securing base and an alignment portion, both of which are integrally formed; an annular notch is formed between them. The alignment portion has at least two pairs of rod alignment openings in a bulb-shaped or keyhole-shaped form with an upper portion larger than a lower portion. Two longitudinal notches extend from near the top across the alignment openings to the rod securing base. The screw body includes a spherical head and a screw rod; the outer diameter of the spherical head is larger than that of the screw rod. The screw body is rotatably connected to the bottom portion of the positioning casing; the spherical head of the screw body is arranged in the spherical pit of the rod securing base.