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Enhancing Electrode Location Assessment in Cochlear Implantation via Computed Tomography Image Fusion
Published on: January 17, 2025
Computed Tomography Estimation of Cochlear Duct Length Can Predict Full Insertion in Cochlear Implantation
James D A Johnston1, Daniel Scoffings, Mark Chung
1*Department of Otolaryngology, Cambridge University Hospitals NHS Foundation Trust †Department of Radiology, Cambridge University Hospitals NHS Foundation Trust ‡Emmeline Centre for Hearing Implants, Cambridge University Hospitals NHS Foundation Trust §Emmeline Centre for Hearing Implants, Cambridge University Hospitals NHS Foundation Trust, and Audiology, Anglia Ruskin University ||Department of Otolaryngology and Emmeline Centre for Hearing Implants, Cambridge University Hospitals NHS Foundation Trust, Cambridge, U.K.
Objective:
To compare the rates of full insertion of electrodes and hearing outcomes obtained with 28-mm and 31-mm cochlear implant electrode arrays. To assess whether cochlear duct length (CDL) estimated by preoperative computed tomography (CT) predicts whether an electrode is fully inserted.
Study Design:
A cohort study compared electrodes inserted and hearing outcomes after implantation with 28-mm or 31-mm arrays. CDL estimated from preoperative CT was compared in patients in whom full insertion of the 28-mm array was achieved compared with patients in whom at least one basal electrode was outside the cochlea.
Setting:
Tertiary referral cochlear implantation center.
Patients:
One hundred forty-eight patients implanted with 28-mm cochlear implant arrays (175 devices) and 74 patients implanted with 31-mm arrays (88 devices).
Intervention:
Cochlear implantation with 28-mm or 31-mm array.
Main Outcome Measures:
Active electrodes at first programming, and at subsequent follow-ups. Bamford-Kowal-Bench sentence and auditory speech sound evaluation test results at 2 to 3 months in adult patients. CDL predicted by preoperative CT.
Results:
There was no difference in full insertion between the 28-mm and 31-mm array cohorts (p = 0.22). Early hearing outcomes at 2 to 3 months showed no difference in mean auditory speech sound evaluation (p = 0.19) or Bamford-Kowal-Bench results (p = 0.853) between the 28-mm and 31-mm cohorts. CDL was shorter in the 22 patients with less than full insertion of the array with a mean length of 28.7 mm compared with 29.6 mm in the 42 patients in whom full insertion was achieved (p = 0.046).
Conclusion:
CT estimation of CDL predicts full insertion after cochlear implantation. Insertion depth does not affect early hearing outcome.
