Telescopic Surgical Distractor with Nested Helical Stages
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Solution Overview
Problem
Current surgical distractors for orthopedic procedures, such as knee replacements, require multiple spacer blocks for varying joint spaces and may compromise joint balance due to external extensions, necessitating a more compact and adjustable solution for accurately determining joint space and tension.
Innovation Solution
A surgical distractor with a telescopic mechanism comprising a base plate, intermediate stages, and a distraction plate, allowing for compact expansion and independent adjustment of joint space, utilizing helical structures for linear movement and a drive mechanism for precise control, enabling efficient assessment of joint space and tension without compromising the natural joint alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple spacer blocks are used to accommodate varying joint spaces, then the adaptability to different joint space sizes is improved, but the device complexity and the number of components required increases
Solution Approach 1:
The distractor employs a telescopic mechanism with multiple intermediate stages that can dynamically adjust the distance between the base plate and distraction plate, transforming a static set of discrete spacer blocks into a single dynamic device capable of continuous adjustment to match varying joint space sizes
Solution Approach 2:
The single distractor device with telescopic adjustment capability serves multiple functions that previously required multiple separate spacer blocks, allowing one device to accommodate a range of joint space sizes through adjustment rather than requiring multiple fixed-size components
2Object-affected harmful factors
If the distractor is made compact to avoid compromising joint balance, then the negative impact on joint alignment is reduced, but the expansion ratio required to measure full joint space increases
Solution Approach 1:
The telescopic mechanism employs nested intermediate stages where each stage contains the next, allowing the distractor to collapse into a compact form factor that minimizes interference with joint balance while maintaining the capability to expand to the full required measurement length when needed
Solution Approach 2:
The distractor is divided into multiple telescopic intermediate stages that can be segmented and nested within each other, enabling the device to achieve a large expansion ratio when extended while maintaining a compact size when retracted, thus resolving the contradiction between compactness and expansion capability
3Adaptability or versatility
If an adjustable trial prosthesis with threaded bar is used to assess joint space, then the ability to vary thickness is improved, but the requirement for a bore extending into bone increases device complexity
Solution Approach 1:
The distractor design extracts the adjustment mechanism from the bone interface, placing the telescopic intermediate stages and drive mechanism entirely within the joint space rather than requiring integration with bone structure, thereby eliminating the need for bone bores while maintaining adjustability
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 distractor provides a compact, adjustable solution that allows for a large expansion ratio, reducing the need for multiple spacer blocks and enabling quick, accurate determination of joint space and tension, optimizing prosthetic implant sizing and joint balance.
Implementation Method 1
The first intermediate stage and the base plate may be coupled together by a helical structure in which relative rotary movement between the first intermediate stage and the base plate is converted into relative linear movement between the first intermediate stage and the base plate
Implementation Method 2
coaxial screw gear sleeve mechanisms include a post with a threaded exterior surface and a corresponding sleeve configured to surround the post, the corresponding sleeve having a threaded interior surface configured to interface with the threaded exterior surface of the post
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A surgical distractor comprising a base plate (2), an intermediate stage (6) telescopically coupled to the base plate (2) and a distraction plate (4) telescopically coupled to the intermediate stage (6). The intermediate stage (6) is arranged to rotate relative to at least one of the base plate (2) and the distraction plate (4) to cause telescopic movement between the intermediate plate (6) and at least one of the base plate (2) and the distraction plate (4) such that the distraction plate (4) moves towards or away from the base plate (2). Surgical instrument kits incorporating distractors and drive elements and a method of distracting two bones within a joint are also disclosed.