Surgeon Survey Shows No Adverse Events With MRI in Patients With Magnetically Controlled Growing Rods (MCGRs)

Regina P Woon; Lindsay M Andras; Hilali Noordeen; Stephen Morris; John Hutchinson; Suken A Shah; Jeff Pawelek; Charles E Johnston; David L Skaggs; Children's Spine Study Group; Growing Spine Study Group

doi:10.1016/j.jspd.2017.10.004

Surgeon Survey Shows No Adverse Events With MRI in Patients With Magnetically Controlled Growing Rods (MCGRs)

Spine Deform. 2018 May-Jun;6(3):299-302. doi: 10.1016/j.jspd.2017.10.004.

Affiliations

¹ Children's Orthopaedic Center, Children's Hospital Los Angeles, 4650 Sunset Blvd. Mailstop #69, Los Angeles, CA 90027, USA.
² The Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
³ North Bristol NHS Trust, Southmead Hospital, Southmead Rd, Bristol BS10 5NB, UK.
⁴ Spire Bristol Hospital, Redland Hill, Bristol BS6 6UT, UK.
⁵ Nemours/Alfred I. duPont Hospital for Children, 1600 Rockland Rd, Wilmington, DE 19803, USA.
⁶ San Diego Center for Spinal Disorders, 4130 La Jolla Village Dr, La Jolla, CA 92037, USA.
⁷ Texas Scottish Rite Hospital for Children, 2222 Welborn St, Dallas, TX 75219, USA.
⁸ Children's Orthopaedic Center, Children's Hospital Los Angeles, 4650 Sunset Blvd. Mailstop #69, Los Angeles, CA 90027, USA. Electronic address: [email protected].
⁹ Children's Spine Foundation, P.O. Box 397, Valley Forge, PA 19481, USA.
¹⁰ Growing Spine Foundation, 555 East Wells St, Suite 1100, Milwaukee, WI 53202, USA.

PMID: 29735140
DOI: 10.1016/j.jspd.2017.10.004

Abstract

Study design: Surgeon survey.

Objectives: To determine if magnetic resonance imaging (MRI) following implantation of magnetically controlled growing rods (MCGRs) is associated with any adverse events.

Summary of background data: Magnetically controlled growing rods have been shown to reduce the need for repeated surgical procedures and improve costs when compared to traditional growing rods, but concerns about MRI compatibility exist. MRIs are often clinically indicated in the EOS population.

Methods: Pediatric spine surgeons who are members of the Growing Spine Study Group, Children's Spine Study Group, and early international users of this technology were surveyed regarding MRI use after performing MCGR surgery.

Results: A total of 118 surgeons were surveyed. Four surgeons reported that 10 patients had an MRI with an implanted MCGR. Loss of fixation (0%, 0/10), movement of implants (0%, 0/10), unintended lengthening/shortening (0%, 0/10), or noticeable heating of MCGR (0%, 0/10) were not observed. No problems were observed with function of the MCGR following MRI, and a mean of 2.1 mm was obtained at the next lengthening (range, 0.5-3.0 mm). Two patients had brain MRIs, both of which could be interpreted. All cervical spine MRIs could be interpreted without excessive artifact (100%, 7/7). Six patients had MRIs of the thoracic or lumbar spine, but these were considered uninterpretable as a result of artifact from the MCGR device (0%, 0/6).

Conclusion: These are the first reported cases of MRI use in humans with MCGR. There were no adverse events observed. MCGR rods lengthened as expected following MRI. MRIs of the brain and cervical spine were able to be interpreted, but MRIs of the thoracolumbar spine could not be interpreted because of MCGR artifact. MRIs can be safely performed in patients with MCGRs; however, MRIs of thoracic and thoracolumbar spine may be of limited clinical benefit because of artifact.

Level of evidence: Level IV, case series.

Keywords: Early onset scoliosis; Magnetic resonance imaging; Magnetically controlled growing rods; Surgeon survey.

MeSH terms

Humans
Magnetic Resonance Imaging / adverse effects*
Magnets*
Orthopedic Procedures / instrumentation*
Scoliosis / surgery*
Spine / diagnostic imaging
Spine / surgery
Surveys and Questionnaires