Pre-clincal Testing, Introduction to Market and Post-Market Surveillance of MAGEC Rods

Question 1

How does an implant come to market in the EU?

Answer 1

• Designed by skilled engineers (maybe in conjunction with surgeons)
• Perhaps pre-clinical laboratory tests (but results confidential) maybe guided by international standards. Checking it works and confirming calculations
• They send the technical file and design dossier to a notified body, may get feedback, then will be awarded a CE mark.
• Often on a basis of substantial equivalence, no clinical requirements may be required.
• They will then be fitted by skilled surgeons
• Post market surveillance, maybe tracked by a joint registry if available.

Question 2

What does it mean if an implant is given a CE mark?

Answer 2

This is given by a notified body, and means it conforms with health, safety and environment protection standards.

Question 3

What type of pre-clinical testing is performed on the MAGEC rods?

Answer 3

Animal models are used for spinal implants in general, mainly pigs and beagles in-particular.

Question 4

What is the issue with using pigs and beagles for animal testing for spinal implants?

Answer 4

This is because pigs and beagles are quadruped, whereas humans are biped.

Question 5

Why is it particularly important an animal test for spinal implants is done on biped animals?

Answer 5

This is because biped models more accurately mimics human posture and consequently they are subject to similar forces due to gravity, which have long been appreciated to be a contributing factor to the development of scoliosis.

Question 6

What animal models can be used to mimic human spine anatomy more reliably?

Answer 6

As it stands, there are no animal models that mimic the human spinal anatomy with all its constraints and weaknesses, which puts it at risk of developing scoliosis.

Question 7

What is BS ISO 18192-3:2017?

Answer 7

This is a standard for implants for surgery. Wear of total intervertebral spine and disc prosthesis.

Question 8

What is ASTM F2423-11 (2016)?

Answer 8

This is a standard guide for functional, kinematic and wear assessment of total disc prosthesis. (American standard)

Question 9

What international standards are there for testing spinal implants?

Answer 9

There are currently no international standards for testing spinal implants.

Question 10

American Company Ellipse tested their spinal implant against what standards?

Answer 10

• ASTM F1717-14
• ASTM F2623-12
• ASTM F1877-05
• ANSI/AAMI/ISO 11137-2

Question 11

What evidence is there from human trials for spinal implants?

Answer 11

Ethics must be considered, we know already that the materials are biocompatible and they’re strong enough. They already have results from conventional growing rods.

Question 12

What type of device are MAGEC rods classified as?

Answer 12

Class IIb, this is high risk, but not the highest risk. This may be changed under the new MDR.

Question 13

Who originally designed and manufactured MAGEC rods?

Answer 13

Ellipse Technologies, an American company.

Question 14

When did MAGEC rods and ERC receive CE mark?

Answer 14

in 2009 according to NICE in 2014.

Question 15

When were modifications made to the design of MAGEC rods ?

Answer 15

in 2010, according to NICE in 2014.

Question 16

When was the first implantation of MAGEC rod in the UK?

Answer 16

in 2011, according to Daily Mail.

Question 17

When were the first clinical results of the MAGEC rods, and where were they from, what was the result?

Answer 17

in 2012, first clinical results, from 5 patients from Hong Kong, funded by Ellipse. Claims to reduce angle from 67 degrees to 29 degrees for two patients.

Question 18

When were the first UK clinical results published for MAGEC rods?

Answer 18

in 2013

Question 19

When were the MAGEC rods first approved in the US by the FDA?

Answer 19

27 Feb 2014.

Question 20

How did the MAGEC rods come to market in the US?

Answer 20

They came to market through the 510k route. The predicate was just a spinal rod.

Question 21

When did NICE release guidance in favour of MAGEC rods, largely based on cost-effectiveness?

Answer 21

June 2014.

Question 22

When were the shorter version of MAGEC rods approved by the FDA?

Answer 22

30 September 2014, the FDA approved the shorter, 70mm MAGEC rods.

Question 23

What was approved by the FDA in May 2015, and how?

Answer 23

The MAGEC 2, this was the addition of a 6mm diameter rod to the product, offering design modifications to remove structural welds and new design features. This was done through 510k approval.

Question 24

When was ellipse bought by NuVasive?

Answer 24

Jan 2016. for $380 million

Question 25

When was another version of the MAGEC rods approved by the FDA, to implement design changes to MAGEC rods 2?

Answer 25

31 Aug 2017, another 510k approval.

Question 26

When was the MAGEC X launched in the US, and when was it launched in the UK?

Answer 26

Summer 2018 in the US, and October 2018 in the UK.

Question 27

Where can all the changes on the MAGEC rods be tracked for the US?

Answer 27

Can track all these changes on the FDA website.

Question 28

Can changes be tracked for MAGEC rods in the EU?

Answer 28

Not at the moment

Question 29

How long does it usually take for a regulator to make alterations?

Answer 29

It usually takes a few months.

Question 30

What is the BSR?

Answer 30

The British Spine Registry, it is nascent. In theory, spinal implants can be tracked using this.

Question 31

Who can access the BSR?

Answer 31

Only spinal surgeons

Question 32

Where can we look for records of post-market surveillance?

Answer 32

MAUDE, there is no EU equivalent. They have many records for MAGEC rods.

Question 33

What have new EU regulations suggested will be made, which is comparable to the FDA?

Answer 33

The EU regulations talk about EU DAMED which would be a big database like MAUDE, to track all medical implants.

Question 34

When should EU DAMED be available?

Answer 34

It was suppose to be available 26 March 2020, however this has been postponed for two years.

Question 35

How else can we find information about what’s happened in the EU in regards to medical implants?

Answer 35

Scientific literature.

Question 36

What does ASTM stand for?

Answer 36

American Society for Testing Materials

Question 37

What is ASTM F1717?

Answer 37

ASTM F1717 is intended to provide a basis for the mechanical comparison amongst past, present and future spinal implants assemblies. It specifies methods for both static and fatigue testing of spinal implant assemblies, in a vertebrectomy model.

Question 38

What are spinal implants tested against?

Answer 38

Spinal Implants are tested according to several ASTM standards

Question 39

What does ASTM F1717 allow the comparison of?

Answer 39

This allows the comparison of spinal implant constructs with different intended spinal locations and methods of applications to the spine. These test methods are not intended to define levels of performance, since sufficient knowledge is not available to predict the consequence of the use of a particular device.

Question 40

How many methods are defined for comparative evaluation of spinal implant assemblies in the ASTM F1717?

Answer 40

There are three static load types and one fatigue test defined for the comparative evaluation of spinal implant assemblies.

Question 41

What do the test methods defined in ASTM F1717 establish?

Answer 41

These test methods establish guidelines for measuring displacements, determining the yield load, and evaluating the stiffness and strength of spinal implant assemblies.

Question 42

Can all spinal constructs be testable in all test configurations of ASTM F1717?

Answer 42

Some spinal constructs may not be testable in all test configurations.

Question 43

What are the four testing procedures of ASTM F1717?

Answer 43

1. Static Compression Bend Test
2. Static Tension Bend Test
3. Static Torsion Test
4. Compressive Bending Fatigue Test

Question 44

What is involved in the ASTM F1717 Static Compression Bend Test?

Answer 44

A) Load at a crosshead displacement rate not to exceed 25mm/min and record that load vs displacement curve
B) Calculate displacement at 2% offset yield, elastic displacement, compressive bending yield load, compressive bending stiffness, compressive bending ultimate displacement and ultimate load.

Question 45

What is involved in the ASTM F1717 Static Tension Bend Test?

Answer 45

A) Load at a crosshead displacement rate not to exceed 25mm/min, and record the load vs displacement curve
B) Calculate displacement at 2% offset yield, elastic displacement, tensile bending yield load, tensile bending stiffness, tensile bending ultimate displacement and ultimate load.

Question 46

What is involved in the ASTM F1717 Static Torsion Test?

Answer 46

A) Load at a rate not to exceed 60 deg/min and record the torque vs angle curve
B) Calculate angle at 2% offset yield, elastic angle, yield torque and torsional stiffness.

Question 47

What is involved in the ASTM F1717 Compressive Bending Fatigue Test?

Answer 47

A) Apply a constant load amplitude sinusoidal control profile at no faster than 5Hz. A constant load ratio, R, for all tests should be established and should be greater than or equal to 10.
B) Evaluate two specimens at the initial fatigue loads. Determine the maximum run out load based on no samples failing prior to 5 million cycles.
C) Continue fatigue testing pairs of specimens until the difference between the load at which a specimen fails and the run out load is no greater than 10% of the compression bending ultimate load.