Implant and reimplantation surgery should be carried out with preservation of residual hearing. The aim of this study is to evaluate the effects of such a surgery on hearing threshold. We report the results on 40 patients, 20 males and 20 females, aged between 5 and 70 (mean 29) years, 16 pre-verbal and 24 post-verbal, with measurable pre-operative auditory thresholds. We used the following implants: Advanced Bionics, Med-El, Cochlear, and MXM Digisonic. Four of the patients underwent cochlear reimplantation owing to device failure. A complete insertion was obtained in all patients. Responses to pure-tone stimuli were evaluated in each ear in pre-implant conditions and 3 months after cochlear implant or reimplantation. The explantation was performed with minimal cochlear trauma and preservation of the explanted electrode integrity. 35% showed no change of the hearing threshold, 45% showed a slight worsening of the hearing threshold level in the implanted ear, and 20% had a total loss of residual hearing. Median increases of threshold levels were 10, 5, 10 and 3 dB HL respectively for 125, 250, 500 and 1 kHz. In the group of 4 patients who underwent cochlear reimplantation, 2 showed no variation of the hearing threshold, 1 preserved an appreciable hearing threshold, and 1 had a total loss of residual hearing. The data seem to suggest that hearing function is rather resistant to mechanical trauma during implant and reimplant surgery; the authors hypothesize a role for direct spiral ganglion activation under intense mechanical stimulation.
Residual hearing thresholds in cochlear implantation and reimplantation
Rigante M;
2007
Abstract
Implant and reimplantation surgery should be carried out with preservation of residual hearing. The aim of this study is to evaluate the effects of such a surgery on hearing threshold. We report the results on 40 patients, 20 males and 20 females, aged between 5 and 70 (mean 29) years, 16 pre-verbal and 24 post-verbal, with measurable pre-operative auditory thresholds. We used the following implants: Advanced Bionics, Med-El, Cochlear, and MXM Digisonic. Four of the patients underwent cochlear reimplantation owing to device failure. A complete insertion was obtained in all patients. Responses to pure-tone stimuli were evaluated in each ear in pre-implant conditions and 3 months after cochlear implant or reimplantation. The explantation was performed with minimal cochlear trauma and preservation of the explanted electrode integrity. 35% showed no change of the hearing threshold, 45% showed a slight worsening of the hearing threshold level in the implanted ear, and 20% had a total loss of residual hearing. Median increases of threshold levels were 10, 5, 10 and 3 dB HL respectively for 125, 250, 500 and 1 kHz. In the group of 4 patients who underwent cochlear reimplantation, 2 showed no variation of the hearing threshold, 1 preserved an appreciable hearing threshold, and 1 had a total loss of residual hearing. The data seem to suggest that hearing function is rather resistant to mechanical trauma during implant and reimplant surgery; the authors hypothesize a role for direct spiral ganglion activation under intense mechanical stimulation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
