Ultrasound-Controlled Manual Magnet Repositioning in Magnet Dislocation of Cochlear Implants

Surgical Versus Noninvasive Manual Repositioning After Cochlear Implant Partial Magnet Dislocation

Objectives: To compare surgical magnet repositioning (SMR) and noninvasive manual magnet repositioning (MMR) as treatments for partial magnet dislocation (PMD) of the internal magnet in a cochlear implant (CI) caused by magnetic resonance imaging (MRI). The primary objective was the success rate, while the secondary objectives were total postinterventional CI downtime and complications. Methods: This single-center retrospective study was conducted at a tertiary referral medical center. Patients with CI treated for PMD between January 1, 2007 and September 30, 2022 were included. SMR served as primary treatment until June 2019 and as secondary treatment after the introduction of MMR. Results: A total of 51 cases of PMD were observed in 42 patients and 43 devices (18 ♀; 24 ♂; 12 with bilateral CI). MMR was performed successfully in 19 out of 20 cases (95%), while 32 cases were managed successfully by SMR. The median age at first magnet repositioning was 53.8 years (minimum 19 years, maximum 93 years). When MMR was performed, the mean time from diagnosis to treatment (0.5 ± 1.5 days vs 9.8 ± 7.6 days; P < .01), the mean time from repositioning to CI reactivation (1.4 ± 4.3 days vs 13.1 ± 6.7 days; P < .01), and the mean total CI downtime (1.9 ± 4.8 days vs 22.9 ± 11.9 days; P < .01) were significantly shorter compared to SMR. Significantly fewer complications were experienced with MMR [n = 0 (0%) vs n = 8 (25%); P = .04]. Conclusion: In case of PMD caused by MRI, noninvasive MMR shows a high success rate with a shorter total CI downtime as well as a lower complication rate compared to SMR. Therefore, MMR should be considered as first line treatment with SMR as a second option in case of failure.

The experience of auditory implant recipients undergoing magnetic resonance imaging: Factors associated with pain

OBJECTIVE

Many patients with cochlear implants (CI) and auditory brainstem implants (ABI) require magnetic resonance imaging (MRI) following implantation. This study explores the patient experience of MRI, identifying factors associated with pain, and the effect of interventions designed to enhance comfort and safety.

METHODS

A prospective observational case series from a tertiary referral unit. Tight head bandaging ± local anaesthetic injection (devices with non-MRI-compatible magnets) or observation alone (implants with MRI-compatible magnets) were employed for 1.5 T MRI of consecutive adult patients with CI or ABI without magnet removal. Pain was recorded via visual analogue scale (1 = no pain, 5 = extreme pain) at three time points; (1) baseline, (2) head bandage applied (3) during scanning. Patient age, device type, body area imaged and total scan time were recorded as variables, alongside adverse events.

RESULTS

Data were collected for 227 MRI scans (34 patients with ABI, 32 with CI). In patients managed with bandaging, pain score after bandaging but prior to scanning (median 2.2) did not differ from pain during scanning (2.1), but both were significantly higher than baseline (1.4, both P ≤ 0.001). Scanning areas other than the head/cervical spine was associated with higher pain scores (P = 0.036). Pain during MRI differed between different manufacturers implants (P ≤ 0.001). Adverse events occurred in 8/227 scans (3.5%), none occurring with devices containing an MRI-compatible magnet.

CONCLUSION

MRI scanning with auditory implant magnets in situ is safe and well tolerated by patients.

Diagnosing complications following cochlear implantation using transcutaneous ultrasound

Purpose

The aim of this study was to investigate the feasibility and reliability of transcutaneous ultrasound for the detection of complications after cochlear implantation.

Methods

In a single center retrospective cohort study, 115 consecutive cases of suspected complications after cochlear implantation (intervention group) were examined. The rate of pathologic ultrasound findings for specific leading symptoms and diagnoses was compared to a control group comprising twenty consecutive cochlear implants in symptom-free patients.

Results

Diagnostic ultrasound showed distinctly more pathologic findings in the intervention group (n = 67; 58.3%; p < 0.001) compared to the control group (n = 1; 5%). Ultrasound revealed significantly more pathologic findings in haematoma or seroma around the implant (n = 17; 100%; p < 0.001; ϕ = 0.94) and magnet dislocation (n = 44; 97.7%; p < 0.001; ϕ = 0.92) confirmed by a strong effect. Ultrasound examination showed a medium to high effect size in patients presenting with local infections (n = 3; 21.4%; p = 0.283; ϕ = 0.25) and skin flap oedema (n = 2; 50%; p = 0.061; ϕ = 0.51). In contrast, ultrasound examinations displayed a low effect size in undefined cephalgia (0%; p = 0.444; ϕ = 0.17) and device malfunction or failure (0%; p > 0.999; ϕ = 0.13).

Conclusion

Transcutaneous ultrasound can be advocated as a feasible and effective method in the diagnostic work-up of magnet dislocation and haematoma or seroma around the implant following cochlear implantation. Contrary, ultrasound findings can be expected to be inconspicuous in patients presenting with undefined cephalgia and device malfunction or failure.