Long-term effect of MRI on sacral anterior root stimulator: the Stoke Mandeville experience.

STUDY

DESIGN

Retrospective review study.

OBJECTIVES

To identify whether it is safe to perform a magnetic resonance imaging (MRI) exam on patients who have a sacral anterior root stimulator (SARS).

SETTING

Adult patients with spinal cord injury and implanted SARS attending the National Spinal Injuries Centre who have had MRI scans.

METHODS

Retrospective review between 1989 and 2010. The effect of the MRI scans on the function of the SARS (Finetech-Brindley, UK) was assessed up to 6 months following MRI at 0.2 and 1.5 T.

RESULTS

A total of 18 patients with SARS implants had MRI scans at 0.2 and 1.5 T of the cervical, thoracic and lumbar spine, head, shoulder and pelvis. MRI examinations were abandoned on two occasions in one patient due to radiofrequency interference. One patient's stimulator ceased to function 5 months following MRI; both of these patients showing complications had their MRI examinations at 0.2 T. There were no adverse effects at 1.5 T. In one patient the SARS was removed within 6 months after MRI due to an unrelated medical condition. A total of 17 patients showed no symptoms that required terminating the examination. In all the 11 patients with a complete and functioning implant before MRI at 1.5 T, the SARS was functioning appropriately, and no change in bladder function was reported up to 6 months following MRI.

CONCLUSION

It is safe to perform an MRI scan on patients with SARS providing the examination is conducted in a 1.5 T system.