Cervical Halo Traction Apparatus

Notice type: Warning

Date: 12/03/2004

It has been brought to the attention of the Irish Medicines Board (IMB) that Cervical Halo traction devices, even those labelled as MRI compatible can cause imaging problems or patient discomfort when worn during an MRI scan.  The problem has not been seen to occur with all patients.    

Halo traction components manufactured from titanium, lluminum or carbon composite materials are non-ferrous and may be labelled as MRI compatible.  However these materials are conductors of electricity and as a result it is theoretically possible for current induction to take place through a patient / device during scanning.   

To date the problem has been reported from two Irish hospitals.  The manufacturer has been unable to identify a definitive cause to the problems experienced in these hospitals.  The distributor for the device in Ireland has written to all Irish customers advising them of the potential problem.

To address the MRI safety issue Jerome Medical have decided, as a precautionary measure, to remove the “MRI Compatible” label from the all new devices manufactured.  Jerome Medical also hope to have a new product manufactured from ceramic and glass available for use in three months.  This product will be labelled MRI Compatible.  In the meantime, multiple factors that could contribute to imaging problems or patient discomfort include:

• The configuration / location of the device within the MRI.  A concentration of metal componentry or metal parts located close to the device core can cause arcing.
• The use of non MRI compatible components within the orthopaedic device e.g. nuts /  bolts / washers.
• The re-use of single use device components, which are no longer safe for use in a MRI. Cervical halo units are sold as single use devices.
• Change to the MRI strength.  Newer MRI device can be more powerful than those used previously and therefore may no longer function within the recommended limits of the orthopaedic device.  

• Ensure that all devices that are sold as single use devices are only use once
• Ensure that MRI compatible devices are configured and positioned in the MRI so as to ensure that they are not too close to the MRI core and that metal components are not  criss-crossing or concentrated in one area 
• Ensure that the use of all MRI compatible devices are reviewed when any changes are made to the MRI strength to ensure that they still remain compatible 
• Ensure that patients screening forms are completed for all patients. (see form attached checklist)
• Report any indications of problems to the IMB

All adverse incidents relating to a Medical Device should be reported to the:   

Medical Devices Department 
Health Products Regulatory Authori
Earlsfort Centre 
Earlsfort Terrace 
Dublin 2   

If you have any enquiries, you may contact the Medical Devices Department at:   

Telephone:     +353-1-6764971 
Fax:               +353-1-6767836 
Email:            vigilance@imb.ie 
Website:         www.hpra.ie 

Enquiries to the manufacturer should be addressed to:   

Jerome Medical 
305 Harper Drive 
Moorestown 
NJ 08057 3239 
USA   

Telephone:     +1-856-234-8603 
Fax:               +1-856-722-5487  


APPENDIX 01   

Although MR is safe for most patients, for certain subjects, MRI may pose unnecessary risk.  Most contraindications that would rule out a subject involve metallic foreign bodies, however, there are several other concerns of which investigators should be aware.  If any question exists regarding a subject's MR compatibility the subject must not be scanned.   

Conditions that Would Rule Out a Subject 

• Cardiac pacemaker 
• Surgical aneurysm clips 
• Neurostimulator
• Implanted pumps
• Metal fragments in body / eyes
• Nitroglycerin patch (rule out if subject cannot remove patch; foil may heat up)
• Coloured contact lenses should not be worn in scanner
• Certain cochlear implants 
• Weight >285 (also consider shoulder and chest size; the diameter of the magnet bore is 55cm).

• Ear implants (most are OK, certain cochlear implants are not) 
• Stents, metal rods, plates or screws in body or mouth
• Injury to eyes involving metal (subject must have X-ray exam to rule out fragments) 
• Previous surgery (if metal left in body) 
• IUD (most are OK, except Copper-7) 
• Hearing aid (should be removed before scanning) 
• Dentures (should be removed before scanning) 
• History of vestibular or inner ear abnormality such as Meniere's Disease
• Prosthetic heart valve (most are plastic now )
• Pregnancy
• Breast feeding (rule out if using Gadolinium)
• Braces (causes severe frontal artifact; rule out for EPI)
• Tattoos or permanent eyeliner (if ink contains metallic specks)    

• Claustrophobia 
• Physical discomfort (body size, back or neck pain, etc.) 
• Movement disorders (i.e. ticks, restless legs, etc., that may cause movement artifact)
• Vision / Hearing problems
• Problems using response devices

• ANYTHING in your pockets
• Metal jewellery (including face and body piercing items)
• Watches
• Hair holders
• Eyeglasses
• Metal on clothing (i.e. metal buttons, snaps or trimming, under wire bras, belt buckles) 
• Eye shadow (many contain metallic specks that can heat up)
• Coloured contact lenses (remind subject to bring a case to store contacts in during scanning)

SN2004(02): Cervical Halo Traction Apparatus