Polyaxial Limb Positioning System with Tapered Rotational Lock
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Solution Overview
Problem
Current limb positioning systems for medical procedures are limited in their ability to make precise adjustments and maintain sterility, often requiring complex repositioning and potentially damaging sterile drapes, while also restricting the range of motion needed for certain surgical procedures.
Innovation Solution
A limb positioning system comprising a clamp assembly, pylon and bar assembly, sled assembly, and limb holding assembly that allows for adjustable and secure attachment to surgical tables, enabling polyaxial motion and easy repositioning of limbs with minimal disruption to the sterile field, using a clamp attachable to patient supports with sliding members and a tapered connector for rotational locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed position limb holder is used to maintain stability, then the limb position is stable, but the ability to make precise adjustments and accommodate different ranges of motion is limited
Solution Approach 1:
The limb holder transitions from a fixed position design to a dynamic, adjustable system that allows movement along multiple axes. The device incorporates sliding mechanisms and adjustable components that enable the limb holder to adapt to different positions and ranges of motion while maintaining stability when positioned, directly resolving the contradiction between stability and adaptability.
Solution Approach 2:
The limb holder is divided into multiple independent adjustable segments and components, each capable of movement along different axes. This segmentation allows the device to provide both stable positioning when locked and flexible adjustment when unlocked, addressing the contradiction between fixed stability and adjustable versatility.
2Adaptability or versatility
If the limb holder is disconnected and repositioned to move the limb, then the limb can be repositioned, but the repositioning process becomes complicated and time-consuming
Solution Approach 1:
The limb holder incorporates dynamic locking and unlocking mechanisms that allow the entire assembly to be repositioned as a single unit without disconnection. The movable components enable smooth adjustment along multiple axes while maintaining connected status, significantly simplifying the repositioning process compared to disconnecting and reattaching components.
Solution Approach 2:
Multiple adjustment functions and components are merged into a unified, integrated assembly that moves together along defined paths. This combination eliminates the need to disconnect individual components for repositioning, reducing procedural complexity while maintaining full repositioning capability.
3Strength
If the limb holder is attached directly to the surgical table, then secure attachment is achieved, but placing sterile drapes becomes difficult and the sterile barrier may be compromised
Solution Approach 1:
The limb holder incorporates a sterile drape-compatible interface that acts as an intermediary between the attachment mechanism and the sterile field. This design allows the attachment components to be positioned such that sterile drapes can be placed underneath without compromising the sterile barrier, while maintaining secure attachment strength to the surgical table.
Solution Approach 2:
The attachment mechanism is designed to attach to the surgical table in a manner that creates vertical clearance, allowing sterile drapes to be positioned in the space between the attachment components and the table surface. This dimensional arrangement preserves both attachment strength and sterile field integrity.
4Measurement precision
If a navigation system with tracker and camera is used to determine limb position, then surgical precision is improved, but the tracker and camera must remain in close proximity requiring restricted limb movement
Solution Approach 1:
The limb holder provides dynamic positioning capabilities that allow the limb to be moved within a controlled range while maintaining the tracker-camera proximity required for navigation. The adjustable mechanisms enable the practitioner to optimize the position for both navigation accuracy and surgical access, preserving measurement precision while allowing necessary movement freedom.
Data Source
AI summary
A limb positioning system includes a clamp assembly, a pylon and bar assembly, a sled assembly, and a limb positioning assembly. The clamp assembly is configured to attach to a bed rail of a surgical table and to accept a pylon connected to a bar. The pylon may have a plurality of pylon bars that are secured by the clamp assembly. A base bar may extend from the pylon, and may be attachable to an extension bar to provide a longer track along which the sled assembly may slide. The sled assembly may be biased to be locked with respect to the base bar. The limb holding assembly may include a boot coupled to the sled via a connector near the heel. The connector may be tapered and insertable into a correspondingly tapered section of a ball that sits within the sled assembly, the ball being capable of polyaxial motion.