Surgical Retractor With Pivotable Arms For Rib Stress Reduction
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Solution Overview
Problem
Conventional surgical retraction devices for sternotomy fail to evenly distribute forces across the sternum, leading to increased tension and pain, particularly due to the varying rigidity of the cranial and caudal sternum halves, which can result in rib fractures and discomfort postoperatively.
Innovation Solution
A surgical retraction device with adjustable retaining elements on spreader arms that allow for variable positioning and resilient mounting, enabling adaptation of forces to the sternum's different sections without manual intervention, thereby reducing stress peaks on individual ribs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional retraction devices with fixed spreading arms are used, then the sternum can be opened, but unfavorable force ratios occur due to different stiffness of cranial and caudal sternum halves
Solution Approach 1:
The spreading arms are made pivotably mounted on the holding device, allowing dynamic adjustment of the spreading angle. This enables the device to adapt to the different stiffness characteristics of cranial and caudal sternum halves, distributing forces more favorably across the ribs during retraction
Solution Approach 2:
The device allows changing the geometric parameters of the spreading arms through pivotal movement. By adjusting the spreading angle and orientation, the force distribution parameters can be optimized to match the varying mechanical properties of different sternum regions
2Ease of operation
If the sternum is opened with conventional devices, then surgical access is achieved, but increased tension occurs in cranially located ribs due to greater stiffness
Solution Approach 1:
The pivotable mounting allows the spreading arms to dynamically adjust during the opening process, reducing concentrated tension on stiff cranial ribs while maintaining adequate surgical access. The movement compensates for stiffness variations, preventing excessive force on vulnerable rib regions
Solution Approach 2:
The device design anticipates the higher stiffness of cranial ribs and incorporates pivotable joints that automatically reduce force transmission to these vulnerable areas during the opening process, cushioning against potential rib fractures before they occur
3Force
If additional readjustment or adjustment possibilities are added to conventional devices, then force distribution can be improved, but the process becomes more complicated and time-consuming
Solution Approach 1:
Instead of complex adjustment mechanisms, the invention uses simple pivotable joints that automatically adapt to the sternum's geometry during opening. This dynamic adaptation achieves favorable force distribution without requiring complicated manual adjustments or additional device components
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 device allows for a gentler opening of the sternum, reducing the risk of rib fractures and postoperative pain by evenly loading the adjoining ribs, thus improving surgical outcomes.
Implementation Method 1
one or more retention elements for retaining bone material, for example, of the severed sternum, are arranged on each of the spreading arms; the at least one retention element is spring-elastically held in its position in the retraction direction relative to the spreader arm
Implementation Method 2
the spreading arms are divided into two sections, with a first section being held on a holding device and a second section pivotally mounted on the first section
Data Source
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AI summary
The invention relates to a surgical retractor, particularly for the retraction of a separated sternum, with a holding device and two spreader arms, wherein the spreader arms are mounted with one end on the holding device, at a distance from each other that is adjustable in a spreading plane, and at least two retaining elements for retention of bone material, for example of the separated sternum, are arranged on each of the spreader arms. To develop this retractor for sternotomy in such a way as to permit gentler opening of the separated sternum, it is proposed that at least one of the retaining elements is mounted such that its position can be modified in the retraction direction with respect to that end of the spreader arm mounted on the holding device.