Faculty Bibliography

OBJECTIVES/HYPOTHESIS: This pilot study details the use of a software tool that uses continuous impedance measurement during electrode insertion, with the eventual potential to assess and optimize electrode position and reduce insertional trauma. STUDY DESIGN: Software development and experimental study with human cadaveric cochleae and two live surgeries. METHODS: A prototype program to measure intracochlear electrode impedance and display it graphically in real time has been developed. The software was evaluated in human cadaveric temporal bones while simultaneously making real-time fluoroscopic recordings and in two live surgeries during intracochlear electrode insertion. RESULTS: Impedance changes were observed with various scalar positions, and values were consistent with those obtained using clinically available software. Using Contour Advance electrodes, impedance values increased after stylet removal, particularly when using the monopolar mode. CONCLUSIONS: Impedance values seem systematically affected by electrode position, with higher values being associated with proximity to the cochlear wall. The new software is capable of acquiring impedance measurements during electrode insertion, and these data may be useful to guide surgeons to achieve optimal and atraumatic electrode insertion, to guide robotic electrode insertion, and to provide insights about electrode position in the cochlea.

OBJECTIVES AND IMPORTANCE: Children with certain congenital malformations of the inner ear, including those with a common cavity defect, have a higher incidence of spontaneous cerebrospinal fluid (CSF) leak and resulting meningitis. However, they may also benefit from cochlear implantation. We suggest that surgical management may be possible that both prevents meningitis and provides hearing rehabilitation during the same procedure. CLINICAL PRESENTATION: A 2-year-old girl with bilateral common cavity defects who had previously undergone cochlear implantation developed contralateral CSF leak resulting in meningitis. INTERVENTION: After resolution of the infection, cochlear implantation was performed at the same time as definitive CSF leak repair. Simultaneous cochlear implantation and repair of the CSF leak successfully decreased the chance of recurrent meningitis in this case. She has been deriving hearing benefit from the bilateral implants. CONCLUSION: This case suggests a role for cochlear implantation to be combined with simultaneous CSF leak repair in children with a cochlear malformation. Furthermore, bilateral cochlear implantation at an early age may be warranted in these patients before CSF leaks and meningitis have occurred.