Ultrasound in diagnosis and treatment of magnet dislocation in patients with cochlear implant

Introduction When conducting a magnet resonance imaging (MRI) examination in patients with cochlear implant (CI), complications related to the magnet can occur in 15-20 %. In patients who present with pain and swelling around the CI after MRI, an X-ray examination is recommended in generally to control the position of the internal magnet. The objective of this study was to determine the utility of sonography in diagnosis and treatment of magnet dislocation in CI patients.

Material and methods All patients who underwent surgical or manual magnet reposition between 01.01.2010 and 15.10.2019 were revised. Inclusion criteria were as follows: suspicion of CI magnet dislocation, preinterventional examination using ultrasound followed by surgical or manual magnet reposition.

Results In total, 33 patients could be included. In 30 out of 33 cases (91%), magnet dislocation was diagnosed with ultrasound; in two cases (6%), evaluation with ultrasound was not possible because of tissue swelling. In one case, the magnet was diagnosed as not dislocated.

In 28 out of 33 cases, the magnet was repositioned surgically. In five cases, an ultrasound- guided manual magnet reposition was performed.

Conclusion Patients with CI who present with pain and/or swelling around the implant after MRI should be examined with ultrasound. Thereby, magnet dislocation can be diagnosed in 91 % and examination with X-ray can be avoided. In patients with partial magnet dislocation, ultrasound-guided manual magnet reposition is primarily recommended.

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Publication History

Article published online:
10 June 2020