Management of patients with magnetically controlled growth rods amidst the global COVID-19 pandemic

Abstract

IntroductionAt the time of writing, we are all coping with the global COVID-19 pandemic. Amongst other things, this has had a significant impact on postponing virtually all routine clinic visits and elective surgeries. Concurrently, the Magnetic Expansion Control (MAGEC) rod has been issued with a number of field safety notices and UK regulator medical device alerts.Methods
This document serves to provide an overview of the current situation regarding the use of MAGEC rods, primarily in the UK, and the impact that the pandemic has had on the management of patients with these rods.Results and Conclusion
The care of each patient must of course be determined on an individual basis; however, the experience of the authors is that a short delay in scheduled distractions and clinic visits will not adversely impact patient treatment. The authors caution against a gap in distractions of longer than 6 months and emphasise the importance of continued remote patient monitoring to identify those who may need to be seen more urgently.

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European Spine Journal
https://doi.org/10.1007/s00586-020-06516-2
FORUM
Management ofpatients withmagnetically controlled growth rods
amidsttheglobal COVID‑19 pandemic
HarryHothi1 · StewartTucker2· MasoodShafafy3· ColinNnadi4· KennethM.C.Cheung5· ElisabettaDalGal1·
MartinaTognini1· JohannHenckel1· JohnSkinner1· AlisterHart1
Received: 22 April 2020 / Revised: 9 June 2020 / Accepted: 18 June 2020
© The Author(s) 2020
Abstract
Introduction At the time of writing, we are all coping with the global COVID-19 pandemic. Amongst other things, this has
had a significant impact on postponing virtually all routine clinic visits and elective surgeries. Concurrently, the Magnetic
Expansion Control (MAGEC) rod has been issued with a number of field safety notices and UK regulator medical device
alerts.
Methods This document serves to provide an overview of the current situation regarding the use of MAGEC rods, primarily
in the UK, and the impact that the pandemic has had on the management of patients with these rods.
Results and Conclusion The care of each patient must of course be determined on an individual basis; however, the experi-
ence of the authors is that a short delay in scheduled distractions and clinic visits will not adversely impact patient treatment.
The authors caution against a gap in distractions of longer than 6 months and emphasise the importance of continued remote
patient monitoring to identify those who may need to be seen more urgently.
Keywords COVID-19· MAGEC rod· MCGR · EOS
Background toMCGRs
MCGRs are used in the surgical treatment of children with
scoliosis; the rods serve to brace the spine and minimise
the progression of scoliosis as the child grows. An external
magnet is used to extend the length (distract) of the rods, in-
line with the growth of the child; this is performed at regu-
lar intervals, usually between 1 and 6months in a routine
outpatient ‘distraction clinic’ visit. These rods are intended
to be removed after they have been extended to their full
length; these may be replaced with longer rods if the patient
is still growing or the patient may undergo other treatment
options if growth has stopped.
In the UK, one design of MCGR has been available for
clinical use, known as the MAGnetic Expansion Control
(MAGEC) rod (NuVasive). Since its first use in 2009, there
have been 7 design iterations of the MAGEC rod, namely:
MAGEC 1.0, 1.1, 1.2, 1.3, 2.0, 2.1 and most recently the
MAGEC X (first used mid-2017).
What are theknown issues?
On the 1 of April 2020, the manufacturer issued an FSN,
voluntarily suspending the supply of all MAGEC rods to the
UK, and the MHRA released an MDA the same day con-
firming this with the action that surgeons in the UK should
not implant MAGEC rods until further notice [1].
The MHRA is now investigating whether the clinical ben-
efits of using these rods continue to outweigh the risks. The
regulator will in exceptional circumstances still consider use
* Harry Hothi
h.hothi@ucl.ac.uk
1 The Royal National Orthopaedic Hospital andInstitute
ofOrthopaedics andMusculoskeletal Science, University
College London, BrockleyHill,StanmoreHA74LP, UK
2 Great Ormond Street Hospital forChildren, NHS Foundation
Trust, London, UK
3 Department ofTrauma andOrthopaedics, Nottingham
University Hospitals NHS Trust, Nottingham, UK
4 Nuffield Orthopaedic Centre, Oxford University Hospital,
Headington, Oxford, UK
5 Department ofOrthopaedics andTraumatology, The
University ofHong Kong, 102 Pokfulam Road, Pokfulam,
HongKongSAR, China

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of MAGEC in patients during this period on a case-by-case
basis.
This action comes as a result of previous FSNs and
MDAs [2, 3] highlighting issues with a fracture/failure of
external and internal components and the generation of tita-
nium wear/corrosion debris [4], in some cases preventing
rod distractions, ultimately requiring early and unplanned
revision, as in Table1.
The availability and use of these devices in other coun-
tries has currently seen no change as a result of action in
the UK; MAGEC 1.3, 2.0 and 2.1 continue to be implanted
routinely.
The exception is the MAGEC X edition, which was
recalled globally by the manufacturer due to the risk of end-
cap separation (Fig.1); the manufacturer has stated, how-
ever, that the rods may still continue to distract or serve as
an internal brace even if end-cap separation has occurred.
Furthermore, given that current information states that this
issue has occurred in 0.5% of patients with this design, the
risk of immediate adverse impacts appears low.
The most common mode of device failure reported in
the literature for previous rod designs (i.e. those other than
MAGEC X) had been a fracture of the internal locking pin,
resulting in an inability for the rod to be lengthened further;
the manufacturer reports a fracture risk of 5%. Similarly, the
rods may still function as an internal brace until they can be
revised at an appropriate time.
Surgeons will of course have two primary considerations
amidst these alerts and the pandemic:
1. Identifying which (if any) of their patients have experi-
enced (or are at risk of experiencing) the implant issues
described above, so as to appropriately manage them.
2. Continuing with timely rod distractions, in-line with the
growth of the child. What dothenormal guidelines say?
The MHRA advises that surgeons should notify all patients
about the possible complications that may occur due to
Table 1 Summary of the issues and clinical risks associated with MAGEC rod designs
Design iteration Implant issue Clinical risk
MAGEC X Risk of a separation of the threaded end cap from the hous-
ing tube after implantation
Internal components may be exposed to
biological fluid, potentially leading to a
failure of the mechanism and the release of
titanium wear and corrosion debris
MAGEC 1.0, 1.1, 1.2 (i.e. rods
manufactured before 26 March
2015)
These rods have an increased risk of a fracture of the inter-
nal locking pin. There is also evidence of a failure of the
O-ring seal in some rods and the generation of titanium
wear/corrosion debris
A fractured locking pin may prevent the rod
from lengthening. There is no evidence
on long-term effect of the sometimes-sig-
nificant debris in these children; however,
excessive debris may also prevent the rod
from extending and lead to discolouration
of surrounding tissue
Fig. 1 Example X-ray images of (a) a rod with a well-fixed end cap
and (b) a rod with a separated end cap [3]

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device failures. Surgeons should continue to use their own
clinical judgement to assess each patient individually and
perform X-ray imaging (and not ultrasound) at least once
every 6months. Patients with the MAGEC X should have
X-ray imaging performed within 3months of the alert date
of 18 March 2020 to do determine if cap separation has
occurred, as in Fig.1.
Under the normal pathway, patients would attend an out-
patient distraction clinic every 1–6months during which
the surgeon/clinical team could discuss these issues, carry
out clinical assessments in person and perform a routine
rod lengthening. These visits could also coincide with X-ray
imaging as suggested by the MHRA.
What dowe doinaCOVID‑19 environment?
The situation with COVID-19 is fast evolving; at the time of
writing, the UK remains under a lockdown to slow down the
spread of the virus with all routine clinic visits and elective
surgeries postponed. In contrast, Hong Kong is still practic-
ing containment measures meaning that some reduced clin-
ics are still able to run but every patient is risk assessed for
having COVID-19 before they are seen.
In light of these circumstances, the suspension of the sup-
ply of MAGEC rods in the UK, and the necessity for all
MAGEC patients to undergo timely distractions, we offer the
following considerations to surgeons, parents and patients
in the UK (Table2).
Determining any adverse impact ofend‑cap
separation orother device failures (including all
MAGEC rod designs implanted)
Routine clinic visits and X-ray imaging should resume when
it is safe and practical to do so within the confines of social
distancing measures. As acknowledged by the MHRA in
their MDA on 1 April 2020 [1], it is likely that the follow-up
of these patients will not be possible within the timeframe
that they have suggested due to the pandemic.
The occurrence of an end-cap separation in the MAGEC
X can only be determined following X-ray imaging at a time-
point that is practically safe and possible.
Surgeon experience in these cases is that the inevitable
delay in the normal follow-up pathway will not adversely
impact the majority of patients. Regular and remote (i.e.
telephone) monitoring of patient comfort may be the best
way to identify patients that may need to be seen urgently.
As an additional consideration, there is evidence of tita-
nium debris being released from the devices due to the fail-
ure modes described above [4]. It is proposed that measures
of titanium levels in blood samples from MAGEC patients
may be a useful additional monitoring tool if it is practically
possible and the appropriate collection, storage and analysis
protocols can be utilised without impacting any resources
required for the management of the pandemic [5]. This,
however, requires further research to better understand the
sensitivity and specificity of this measure.
The appropriate time betweendistraction clinics
inlight ofCOVID‑19
Under normal circumstances, a distraction frequency of
once every 1–6months is typical. Under the current cir-
cumstances, it is likely that all distractions (where possible)
will have to be delayed to a 6-month frequency with the
expectation that we will have passed the peak of this pan-
demic by then.
In the clinical experience of the treating MAGEC sur-
geons, the majority of patients will not be impacted by a
short delay in their distractions; however, there should not
be a gap of more than 6months unless in exceptional cir-
cumstances. The surgeon and/or clinical nurse specialists
will remain in touch with patients remotely. Some children
Table 2 Summary of current guidance and suggested changes under COVID-19
Design iteration Normal guidance Under COVID-19
MAGEC X Anteroposterior X-ray imaging within
3months of the original alert on 18 March
2020 to determine if cap separation has
occurred (Fig.1)
X-ray and clinical assessment when it is safe and practical to do so.
Acknowledgement that this is likely to be beyond the timeframe suggested
by the MHRA. Titanium blood tests may be a useful surrogate for implant
performance (relating to wear/corrosion) in the interim, however, needs
further research
All MAGEC rods Advise all patients about the possible
complications resulting from the failure of
components as described in previous FSNs.
Each patient should be assessed using own
clinical judgement and using X-ray imaging
(rather than ultrasound) at least once every
6months
All MAGEC rods Distraction clinic every 3–6months Distraction interval of every 6months if possible. Earlier if child experiences
mild discomfort

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will, however, experience mild discomfort indicative that
the rod requires lengthening or there may be obvious curve
progression; these patients may be seen sooner, and length-
ening brought forward. Once the situation returns to normal,
surgeons can shorten significantly the gap between lengthen-
ings if needed to catch up with a patient’s growth.
In circumstances in which surgery is inevitably required
to revise a failed implant or indeed if a planned removal is
necessary to facilitate final fusion, a senior clinician within
the framework of a Multidisciplinary Team (MDT) needs to
have a balanced discussion about the risk of COVID trans-
mission with the patient and family regarding suitability of
proceeding imminently or delaying definitive surgery to a
later date.
As countries begin to lift lockdown measures, MDT deci-
sion making will be effective at managing the return to nor-
mality in terms of patient management, whilst being mindful
that some risk from the virus may remain for a considerable
time yet.
Conclusion
There is currently much uncertainty regarding the use of
MCGRs in the UK due to recent regulator MDAs. The man-
agement of these patients has been further complicated by
the current COVID-19 pandemic. The care of each patient
must of course be determined on an individual basis; how-
ever, the experience of the authors is that a short delay in
scheduled distractions and clinic visits will not adversely
impact patient treatment. The authors caution against a gap
in distractions of longer than 6months and emphasise the
importance of continued remote patient monitoring to iden-
tify those who may need to be seen more urgently.
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