What might be the effects of titanium debris around the spines of children with scoliosis?

2 December 2020

Dr Alison Tyson-Capper, Professor of Molecular Cell Biology and Dr Tom Joyce, Professor of Orthopaedic Engineering, are part of a study, funded by the British Scoliosis Research Foundation (BSRF), into what the effects of titanium debris around the spines of children with scoliosis might be. Titanium is used in the manufacturing of growing rods like the MAGEC spinal rods, which in April 2020 were suspended from supply in the UK. The UK and Ireland are the only countries to have currently suspended the use of MAGEC rods.

Dr Joyce is an Orthopaedic Engineer and has previously worked on assessing retrieved hip and knee implants to tell what’s gone right and what’s gone wrong with these implants. He was approached by a Spinal Surgeon to study the MAGEC implants after they’ve come out of the body and found that there was a substantial volume of debris from the titanium. The excess titanium debris was leading to a blackening of tissue near the rod. There was no documentation of what the adverse effect may be of this titanium wear debris and any related titanium ions as the MAGEC rods had only been used for about 10 years.

Dr Joyce, explaining why this excess debris is a concern says “Titanium is used in a lot of implants so it generally has a positive reputation. One of the concerns we have with MAGEC rods is that the volume of wear debris that’s created is huge compared with hip or knee implants. There was another case with a type of artificial hip joint that showed that once a certain volume of metallic debris was reached, the body became sensitive to it and eventually rejected that metal implant. So, we’re seeing if there is a similar response to titanium wear from MAGEC rods.” 

Dr Joyce partnered with Dr Tyson-Capper to create a research project that could assess what the biological response of titanium around the spine may be. Dr Tyson-Capper herself has a friend with scoliosis and had previously identified the biological effects of cobalt and was the first to find that there was an inflammatory response in human cells from the metal cobalt in hip and knee implants.

They aim to understand failings and identify improvements so that people can design their implants to be safe and effective and surgeons can be offering the best possible rods and be equipped with the most up-to-date information about that treatment. They also want to address the need for collaboration on international standards when it comes to the best way to test spinal rods before they are implanted.

This project will have further phases but thanks to the funding supplied by the BSRF, they have collected the necessary data and samples and have determined the key biomarkers that are to be assessed.

 

What are MAGEC rods and growing rods?

MAGEC rods were developed to be used in children with early onset scoliosis as an implant that could control the curve progression whilst allowing the spine to grow. Further growth at that age is critical for breathing and lung development.  MAGEC stands for MAGnetic Expansion Control and is an alternative to the traditional growing rod.

Traditional growing rods are placed into a child’s back during surgery. Because children grow so quickly, the rods need to be lengthened about every six months. Each time the rods are lengthened surgery is needed.

The MAGEC system combines traditional growing rods with new magnet technology. MAGEC rods are put into a child’s back during surgery one time. After that, they can be lengthened in clinic using a remote control and powerful magnets. This allows a child to grow without needing repeat surgeries.

On 1 April 2020, the UK medical devices regulator, the MHRA, issued a medical device alert to all clinicians stating that they should cease implanting MAGEC spinal rods until further notice, while independent interrogation is being done.

For more information please see the Scoliosis Association UK MAGEC Q&A article, originally published in Backbone magazine – Spring 2019. https://www.sauk.org.uk/downloads/magec-rods---questions-and-answers.pdf

Read the completed project final report here 

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