Steerable Bone Access Rod with Friction-Reducing Cannula
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Solution Overview
Problem
Conventional surgical tools for vertebral compression fractures face challenges with high friction between curved needles and outer cannulas, making it difficult to insert curved needles into vertebral bodies without damaging tissue, and existing friction reduction solutions lack secure attachment to the handle for controlled deployment.
Innovation Solution
A control mechanism featuring a handle with a sliding ring, shaft, and drive shaft, along with a friction reduction cannula secured to the shaft, allowing axial rotation and sliding while preventing axial rotation of the drive shaft, and a steerable rod with a preformed bend made from superelastic materials, enabling controlled deployment and reduced friction during insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a curved needle is used to access the vertebral body, then the ability to create cavities and inject cement is improved, but friction between the needle and outer cannula increases making insertion difficult
Solution Approach 1:
A friction reduction covering is introduced as an intermediary component between the curved needle and the outer cannula. This covering is configured to slide over the curved needle during insertion, reducing friction and enabling easier passage through the cannula while maintaining the curved needle's ability to create cavities and inject cement into the vertebral body
2Ease of operation
If a friction reduction covering is used, then friction during insertion is reduced, but control of the curved needle deployment becomes difficult
Solution Approach 1:
The device is segmented into functionally independent components: a friction reduction covering for reducing friction, a curved needle for cavity creation, and a control mechanism with a drive shaft and sliding ring for deployment control. Each component performs its specific function while being controlled independently, simplifying the overall control architecture
Solution Approach 2:
The control mechanism incorporates a sliding ring that can move along the drive shaft and a locking mechanism that can engage at different positions. This dynamic system allows the curved needle to be deployed at controlled positions along its length, providing precise control over the insertion depth and orientation while maintaining low friction during the insertion 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 mechanism facilitates controlled deployment of the curved needle with reduced friction, allowing for precise cavity creation and material injection in vertebral bodies, enhancing surgical precision and minimizing tissue damage.
Implementation Method 1
the sliding ring is threadedly connected to the sliding shaft
Implementation Method 2
blocking means which prevent axial rotation between the drive shaft and the sliding shaft
Implementation Method 3
connecting means which prevent axial displacement between the drive shaft and the sliding ring
Implementation Method 4
a friction reduction cannula configured to receive the rod
Implementation Method 5
the rod having a preformed bent and at least one key
Implementation Method 6
Such curved needles are often made of shape-memory alloys
Data Source
AI summary
A steerable system and methods for accessing bone. A control mechanism includes a handle configured to be detachably secured to a trocar. The handle includes a drive shaft coupled to a sliding shaft such that relative rotation is prevented and relative translation is permitted. A rod having a preformed bend is removably disposed within the cannula. The rod is prevented from rotating relative to the drive shaft such that a deflection plane of the preformed bend is predefined relative to each of the sliding shaft, the handle, and the trocar when the handle is coupled to the trocar. Rotating a sliding ring of the handle translates the drive shaft to advance the rod beyond the trocar such that the preformed bend extends laterally out of the trocar in the deflection plane. The rod may be removed from the cannula, and material may be injected through the cannula.