UCL and NSO: Giving children with scoliosis a new lease of life with innovative spine implants

UCL and NSO: Giving children with scoliosis a new lease of life with innovative spine implants

 

11 July 2024

A key project, supported by UCL Consultants (UCLC), is with medical device company NuVasive Specialized Orthopedics (NSO), now a part of Globus Medical, focused on Magnetically Controlled Growing Rods (MCGRs). These adjustable rods are used in the surgical treatment of children with Early Onset Scoliosis (EOS) to brace the spine during a child’s growth, limiting spinal deformity. 

MCGRs are non-invasively distracted (made longer) during treatment, an alternative to traditional treatments which require repeat operations to lengthen the spinal rods. When the surgical team deems necessary and/or when treatment is complete, MCGRs are removed from patients. By retrieving and analysing all types of explanted rods, the UCL team provides important information to the manufacturer and this field of medicine. This helps to identify and understand risk factors in order to improve future performance of devices for use in treating EOS.

The UCL team is led by Professor Alister Hart, Consultant Orthopaedic Surgeon at the Royal National Orthopaedic Hospital (RNOH) and Chair of Academic Clinical Orthopaedics at UCL’s Division of Surgery & Interventional Science – alongside Dr Harry Hothi, Implant Science Fellow at RNOH and Honorary Associate Professor at UCL’s Department of Mechanical Engineering. Dr Johann Henckel, 
Surgical Technology Researcher and Senior Fellow in Trauma & Orthopaedic surgery is also a key team member.

They comment: “Over the past seven years, our research team has analysed retrieved MCGRs to better understand how they perform in patients; indeed, we now have the largest catalogue of retrieved MCGRs anywhere in the world. 

“We’ve combined engineering analysis with clinical and medical imaging data associated with each patient to help us untangle the many factors related to the surgeon, the implant, and the patient outcomes in the use of these EOS devices.”

A potential game changer for scoliosis

EOS is a condition characterised by a curvature of the spine, diagnosed in children before the age of 10 years. It can sometimes resolve by itself or using non-surgical methods such as bracing. In other cases, however, the severity of spine curvature can worsen as the child grows, impairing lung growth (thoracic insufficiency syndrome) with potentially life-threatening results. 

In these cases, surgical intervention is often necessary. Historically, specialised spinal rods, which prop the spine, would be surgically implanted and need to be manually lengthened periodically during subsequent surgical interventions as the child grows.

First used in 2009, MCGRs can be lengthened magnetically from outside the body without the need for additional surgery once they are in place. Understanding their performance as an alternative to traditional techniques and devices continues to be critical in advancing evidence-based decision-making by care teams and families in this rare and challenging patient population.

Getting to the bottom of the issue

The desire for additional and enhanced evidence on MCGRs prompted the UCL team to perform independent retrieval analysis research on the devices on a consultancy basis as part of agreements facilitated by UCLC. This involved the team setting up a network of surgeons across the UK and Ireland to facilitate the research. Much of the work took place at the RNOH Implant Science Centre and the London Implant Retrieval Centre (LIRC), which Professor Hart set up in 2008. 

As MCGRs have been increasingly used in EOS patients, largely due to the benefit of avoiding repeated surgeries in these children, better data were sought to assess the optimised use of these and other devices in EOS. As a result, various authorities temporarily paused the implantation of MCGRs while additional data were analysed. During this period, the UCL team investigated the additional data, and the results have been published in peer-reviewed journals. 

While the devices have returned to use in the EU since 2021, only recently, in 2024, has the device become available again to UK surgeons and patients. UCL researchers have maintained an active research program and partnership with NSO, on behalf of the medical and patient community.

From a regulatory point of view, the team’s analysis reports have been used by the UK’s MHRA as part of their post-market surveillance of these implant devices.

Innovative performance monitoring of implants

In 2022, the UCL team initiated a prospective study to investigate if regular blood testing of patients with titanium orthopaedic implants could be used to assess their performance in patients. Their aim was to understand if blood metal ion levels could be used as a biomarker for implant function in these patients.

The method was subsequently adopted by the MHRA, which in March 2023 requested that the blood biomarker test be performed to support the reintroduction of a type of implant called Precice nails. These magnetically controlled limb-lengthening nails, also manufactured by NSO, are primarily used in patients with a difference in the lengths of their legs. 

The MHRA’s recent announcement that MCGRs could once again be used to treat patients in the UK, was conditional on the completion of the blood analysis work initiated by the UCL research team.

Academic team: Professor Alister Hart, Dr Harry Hothi, Dr Johann Henckel

UCL Department:  Division of Surgery & Interventional Science and Mechanical EngineeringLondon Implant Retrieval Centre (LIRC)