UK bioengineers have developed a low-cost, easy-to-manufacture stabiliser for bone fractures to help in regions where such devices are expensive or in short supply and people sometimes resort to homemade options.
Every year, there are millions of open long bone fracture cases in low- and middle-income countries (LMICs) due to high-energy trauma – for example traffic accidents and conflict injuries - highlighted the authors of a new study, published in Frontiers in Medical Technology. They added that approximately 70% of fractures in LMICs are caused by traffic accidents, yet this "hides the local effects in warfare" where fractures may be exclusively caused by conflict.
Given the severity of the soft tissue damage, as well as the lack of advanced resources and healthcare training, external fixators play a critical role in treating these fractures in LMICs, the authors explained. However, as well as the lack of affordability of most commercial fixators in these countries, there is also a lack of availability, resulting in the creation of homemade external fixators in conflict zones, which "may lead to serious complications or improper healing" they said.
To address these needs, the scientists set out to develop a low-cost, locally manufacturable unilateral external fixator for LMICs, which would also address the shortage in these countries and "enable the surge capacity" in conflict regions or unforeseeable events, explained the authors.
Low Cost and Lightweight Design
Following detailed fieldwork and after documenting clinical and functional requirements, the specifications for the design were that it be relatively lightweight, easy to use/reuse, made from readily available material, manufacturable using conventional workshop equipment, and provide stiffness similar to commercial fixators
The engineers developed the device, named the 'Imperial external fixator', which they described as 'low cost", with a "lightweight" design, that can be manufactured locally to international standards. It consists of four clamping systems and a rod, which can be manufactured from stainless steel and aluminium - readily available materials - using conventional manufacturing techniques, such as milling and turning. The authors highlighted that their device is a "fraction of the cost of commercial devices".
Lead researcher Dr Mehdi Saeidi, department of bioengineering, Imperial College London, said: "We have managed to develop an external fixator that is one-tenth of the cost of commercial devices but with similar performance. This device can provide surge capacity for conflict zones or in response to unpredictable incidents and situations, which was the case with the war in Ukraine."
The device was tested in cadaver leg bones - where it was found to have similar stiffness to commercial devices - as well as undergoing mechanical testing that simulated pressure on the device to demonstrate its ability to keep the bones in position over a longer term. It is currently being tested in Sri Lanka for road traffic accidents, and in Gaza and Ukraine where it is being used for gunshot wounds and other conflict trauma.
"Because of the precision of the parts, initial tests showed that the fixator would need to be built by highly skilled operators or using advanced machinery," the authors pointed out. So the engineers also developed a manufacturing toolkit with components, including drill bits, a saw, and cutting guides, to make the manufacturing easier, faster, and reproducible with high accuracy.
Comparable Performance to Commercial Devices
Professor Ghassan Abu-Sitt, from the American University of Beirut, said: "In previous wars, hospitals in Gaza had run out of external fixators, which jeopardised patient care. Developing the capacity to manufacture fixators locally means that this will not happen again."
Professor Jonathan Jeffers, department of mechanical engineering, Imperial College London, and one of the study investigators, said: "This work shows how basic engineering can mitigate suffering in the most dreadful of situations. The Ukraine situation is exactly why this project was conceived and demonstrates the ability to respond to surge demand."
The authors acknowledged some limitations of their design and testing, including that clinical results are not presented and neither are results on the ability of the device to be cleaned, sterilised, and reused - factors that are currently being researched.
The authors concluded that their device was "affordable" and had "comparable" performance to a commonly used commercial device. They added that the device could be manufactured locally to international standards with minimal skills.
The team now expects to roll out the design to more LMICs at a larger scale with the help of partners in the World Health Organisation and the United Nations Development Programme.
The research was funded by the NIHR (project reference 16/137/45) using UK aid from the UK Government to support global health research. JJ acknowledges funding from the National Institute for Health Research (NIHR) professorship grant ref NIHR300013.
