Value of Routine Plain X-Ray Position Checks after Cochlear Implantation

Abstract

Objective: To analyze the value of a routine x-ray position check after cochlear implantation and to assess if an increased resistance during electrode insertion is a sufficient predictor of electrode misplacement. Study Design: Retrospective data collection. Setting: University hospital. Methods: Plain x-rays (Stenvers' projection) and the respective surgery reports of 218 patients having received cochlear implantation (243 ears) were analyzed for possible electrode misplacements and intraoperative conspicuities during electrode insertion. Results: Electrode misplacement (tip-over, loop, kinking, scalar transition, and incomplete insertion) was observed in 8% of the entire study cohort, but only in 5% if cases with inner ear dysplasia or labyrinthine ossification (n = 28) were excluded from analysis. Intraoperatively, an increased resistance during electrode insertion was found in 16% but only in 8% when cases with inner ear dysplasia or labyrinthine ossification were excluded. The intraoperative finding of an increased resistance during electrode insertion had a sensitivity of 55% and a specificity of 88% for predicting radiographically confirmed electrode misplacements (positive predictive value, 29%; negative predicting value, 96%). Conclusion: Nearly half of the cases of electrode misplacement would have been overlooked if radiographic position checks would have been done only in patients with intraoperative conspicuities during electrode insertion. This finding advocates routine radiographic position checks, although electrode misplacements are relatively rare in patients with regular inner ear anatomy.

Clinical investigation of the Nucleus Slim Modiolar Electrode

“…Reports of fold-over in literature vary between 0.8-5.6% for all electrode types/manufacturers as follows: 0.8% [Dirr et al, 2013], 2% [Zuniga et al, 2017], and 5.6% [Grolman et al, 2009]. The large range in reporting is likely attributed to the design of the studies, which in many cases were retrospective case reviews [Dirr et al, 2013;Zuniga et al, 2017] and therefore only captured fold-overs left in situ, as opposed to prospective studies [Grolman et al, 2009] reporting fold-overs identified intraoperatively. The rate of 4.4% (2 out of 45) identified in the current study is representative of a prospective approach rather than the retrospective case reviews which typically report lower rates of fold.…”

The evaluation of a slim perimodiolar electrode: surgical technique in relation to intracochlear position and cochlear implant outcomes

“…In two other studies that investigated the SPE, 4.5% and 7.7% tip fold-over was reported [12,15]. For comparison, in three studies, including conventional precurved CI electrode types, tip fold-over was found in 0.8%, 2% and 5.6% of the cases [21][22][23]. The slim and flexible design of the electrode is the obvious explanation for the higher frequency of tip fold-over in the SPE compared to conventional precurved electrodes.…”

Prevalence of Extracochlear Electrodes: Computerized Tomography Scans, Cochlear Implant Maps, and Operative Reports

“…Before CI mapping changes can be made, the audiologist must first become aware that electrodes are extracochlear potentially through the use of postoperative imaging. Several studies have investigated and support the use of postoperative imaging to evaluate electrode insertion depth and position in the cochlea 24,26,[28][29][30][31][32][33][34][35][36] , and it has the added benefit of giving feedback regarding tip-foldover 37 .…”