External Fixator Rod Engagement and Wire Bending

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Solution Overview

Problem

Current ILIZAROV™ external fixators cause significant discomfort and pain to patients and are difficult to apply due to the form of engagement of rods to rings, and bending wires poses a risk of infection for both surgeons and patients.

Innovation Solution

The design includes half rings with ledged areas and channel slots for rods, allowing for easy adjustment and secure fixation, along with a mechanism to safely bend KIRSCHNER™ wires using an apparatus with a handle to prevent injury.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If threaded rods are passed through holes at regular intervals on the rings and secured by means of nuts, then the rings and rods can be assembled into a stable cage-like structure, but the form of engagement causes significant discomfort and pain to the patient and difficulty in mounting the fixture

Engineering Contradiction:

Improvestability of cage-like structureVSAvoidease of mounting fixture

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The rod engagement mechanism is divided into two separate components: a rod with a square cross-section and a corresponding square hole in the ring. This segmentation allows the rod to be inserted through the hole and then rotated 90 degrees to engage, creating a secure connection without requiring threading or nuts. The segmentation simplifies the assembly process while maintaining structural stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using threaded rods that require screwing nuts on and off for adjustment, the invention inverts the approach by using a square rod that is inserted and then rotated into place. The adjustment mechanism is inverted from threaded engagement to rotational engagement, allowing for easier mounting and adjustment by the surgeon.

Inventive Principle:

Principle #13The other way round (Inversion)

2Stability of the object's composition

If KIRSCHNERTM wires are bent over to secure them, then the wires are fixed in place, but bending over the wires poses a risk of infection for both the surgeon and the patient

Engineering Contradiction:

Improvefixation of KIRSCHNERTM wiresVSAvoidrisk of infection

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

A dedicated wire bending apparatus is introduced as an intermediary tool between the surgeon and the KIRSCHNER wire. This apparatus includes a holder to secure the wire and a bending mechanism that performs the bending action at a distance from the surgical site. By using this intermediary device, the surgeon avoids direct manual bending of the wire, thereby reducing the risk of contamination and infection transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11510703B2External fixator

Publication Date: 2022.11.29 YEDITEPE UNIVERSITESI

AI summary

An external fixator utilized in orthopedic surgeries such as the repair of segmental fractures, correction of congenital or development deformities, and limb lengthening. The external fixator is comprised of half rings that utilize connectors to form full rings, threaded rods that fit into rod holes, channel slots, wires that pass through bone and soft tissue, and fixation bolts that can be positioned with minimal effort by a surgeon, minimal pain to a patient, and minimal risk of infection.