The French National Cochlear Implant Registry (EPIIC): Cochlear implantation in adults over 65years old.

OBJECTIVES: To analyze the performance of cochlear implants in French patients aged 65 and over, implanted between 2012 and 2016, using data from the French national registry for cochlear implants (EPIIC). MATERIALS AND METHODS: The French national registry incorporates patient data from before implantation and for three years after implantation, stratified in different age groups (18-39, 40-64years, 65-74years and>75years). Here, we assessed the latter two categories. Hearing was assessed using mono- and disyllabic words in a silent background. The Category of Auditory Performance (CAP) scale was also implemented and subjects took the Abbreviated Profile of Hearing Aid Benefit (Aphab) questionnaire. RESULTS: The population aged over 65 accounted for 38% (n=1193) of the 3178 adult implanted patients. The performance for mono- and disyllabic words in silence, the CAP scores and the APHAB questionnaire answers for ease of communication, background noise and reverberation were dramatically improved at one year post-implantation (P<0.0001 for each score) and remained stable between one and three years thereafter. The percentage improvement was similar across all age groups. The scores for loud-noise intolerance did not change after cochlear implantation in any age group. CONCLUSION: Cochlear implants improve hearing and communication in subjects aged 65 and over, with comparable efficiency to that achieved in younger subjects. Cochlear implantation should thus be proposed whenever hearing aids provide only limited benefit. However, between 2012 and 2016, cochlear implantation was given to less than 1% of the French population aged 65 and over with profound deafness.

Rehabilitation of telephone communication in cochlear-implanted adults.

OBJECTIVES: Telephone use correlates with quality of life, and is one of the most important expectations of cochlear implant candidates. The aim of the present study was to assess the benefit of a progressive intensive 18-session training program, conducted by telephone in cochlear implant recipients. MATERIAL AND METHODS: Nine cochlear-implanted adults underwent telerehabilitation focused on telephone use, with before-and-after assessment of: auditory performance, on Lafon monosyllabic words and MBAA sentences in quiet, cocktail-party noise and by phone; telephone use, on ad-hoc surveys and number of calls per week; and quality of life on ERSA and APHAB questionnaires. RESULTS: Before training, monosyllabic word comprehension was poorer by telephone than by direct voice (64±5.7% vs. 26±5.3%; P<0.05). After the 6-week training, there was improvement in the "note taking" telephone message task (85.0±3.7 vs. 50.0±9.0 out of 100; P<0.001), daily phone use (57.0±4.3 vs. 29±5.4 out of 100; P<0.0001), and number of calls in the week before assessment (0.0±0.0 vs. 11.0±3.0; P<0.0001). CONCLUSIONS: A progressive intensive training program by telephone improved phone use in the daily life of cochlear-implanted adults.

Neurofibromatosis type 2: Hearing preservation and rehabilitation.

The main manifestation of neurofibromatosis type 2 (NF2) is the development of bilateral vestibular schwannomas (VS). Consequently, one of the most severe functional sequelae is bilateral sensorineural hearing loss, caused by spontaneous tumor progression and/or treatment-related damage (surgery or radiosurgery). Preserving or restoring hearing is still challenging in NF2 no matter the strategy applied to each individual based on the natural history of VS. In this review, the different strategies for hearing preservation or rehabilitation are discussed and illustrated by several cases. A decisional algorithm for NF2 patients with VS is proposed that takes into consideration the tumor size and hearing level.

Anatomical and functional results of ossiculoplasty using titanium prosthesis.

Titanium ossicular chain replacement prosthesis is often used for rehabilitation of the columellar effect in otologic surgeries. This retrospective study aims to analyse the anatomical and functional results of surgeries in which a titanium prosthesis was used. Two hundred and eighty procedures in 256 patients operated on in a tertiary referral center were analysed. Aetiologies, preoperative audiograms, peroperative data and postoperative outcomes at 2 and 12 months postoperatively were reviewed. Chronic suppurative otitis media with or without cholesteatoma was the main aetiology (89%). There was no difference in anatomical results between partial and total ossicular replacement prosthesis, with an overall dislocation rate of 6%, and an overall extrusion rate of 3%. Regarding functional results, a postoperative air-bone gap ≤ 20 dB was achieved in 65% of cases, with a better result for partial compared to total ossiculoplasty (p = 0.02). A significant difference in air bone gap closure was found when comparing aetiologies, with a higher air-bone gap closure in malformation cases compared to chronic suppurative otitis media with cholesteatoma or retraction cases (p = 0.03). Ossiculoplasty using titanium prosthesis is a safe and effective procedure for rehabilitation of hearing loss, which allows reaching an air-bone gap ≤ 20 dB in the majority of patients.

Intraoperative Conebeam CT for Assessment of Intracochlear Positioning of Electrode Arrays in Adult Recipients of Cochlear Implants.

BACKGROUND AND PURPOSE: Intraoperative conebeam CT has been introduced into the operating room and provides quick radiologic feedback. This study aimed to investigate its utility in the assessment of the positioning of the electrode array after cochlear implantation. MATERIALS AND METHODS: This was a retrospective study of 51 patients (65 ears) with intraoperative imaging by conebeam CT (O-arm) after cochlear implantation between 2013 and 2017. Correct placement into the cochlea was immediately identified. Positioning assessments were later analyzed with OsiriX software. RESULTS: Intraoperative imaging was quickly performed in all cases. No misplacement into the vestibule or semicircular canals was found. A foldover of the implanted array was identified in 1 patient. Secondary analysis by 2 raters showed excellent agreement on insertion depth angle (intraclass correlation = 0.96, P < .001) and length of insertion of the electrode array (intraclass correlation coefficient = 0.93, P = .04) measurements. The evaluation of the number of extracochlear electrodes was identical between the 2 raters in 78% of cases (Cohen κ = 0.55, P < .001). The scalar position was inconsistent between raters. When we compared O-arm and high-resolution CT images in 14 cases, the agreement was excellent for insertion depth angle (intraclass correlation coefficient = 0.97, P < .001) and insertion length (intraclass correlation coefficient = 0.98, P < .001), good for the number of extracochlear electrodes (Cohen κ = 0.63, P = .01), but moderate for the scalar position (Cohen κ = 0.59, P = .02). CONCLUSIONS: Intraoperative conebeam CT using the O-arm is a safe, rapid, easy, and reliable procedure to immediately identify a misplacement or foldover of an electrode array. The insertion depth angle, insertion length, and number of electrodes inserted can be accurately assessed.

International consensus (ICON) on treatment of sudden sensorineural hearing loss.

Sudden sensorineural hearing loss (SSNHL) is a common and alarming symptom that often prompts an urgent visit to an ENT specialist. Treatment of SSNHL remains one of the most problematic issues for contemporary otorhinolaryngology: although many meta-analyses and national guidelines have been issued, management is not standardized in terms of medical treatment, and duration and route of administration. We present several methodological suggestions for the study of treatments for SSNHL. These were developed from the existing level of evidence of the main treatments used in SSNHL by experts who convened at the IFOS 2017 ENT World Congress in Paris, France. All panelists agreed that one of the main limitations present in studies on SSNHL is related to the wide heterogeneity, which characterizes both the initial hearing deficit and the amount of hearing recovery. Although evidence of the efficacy of systemic steroids cannot be considered as strong enough to recommend their use, it is still the most widespread primary therapy and can be considered as the current standard of care. Therefore, systemic steroids stand as an adequate control for any innovative treatment. To reduce the number of subjects we suggest that the inclusion criteria should be restricted to moderate to profound levels of hearing loss. The efficacy of trans-tympanic steroids as a salvage therapy was suggested in several reports on small populations and needs to be confirmed with larger randomized controlled trials.

Natural history of vestibular schwannomas and hearing loss in NF2 patients.

CONTEXT AND OBJECTIVE: Bilateral vestibular schwannomas are the hallmark of neurofibromatosis 2 (NF2), occurring in 95% of patients. These tumors are associated with significant morbidity due to hearing loss, tinnitus, imbalance and facial weakness. As radiosurgery and chemotherapy have been recently introduced in the treatment armamentarium in addition to surgery, a thorough evaluation of vestibular schwannoma natural history is mandatory to determine the role and timing of each treatment modality. METHODS: An exhaustive review of the literature was performed using the PubMed database concerning the natural history of tumor growth and hearing loss in NF2 patients with vestibular schwannomas. RESULTS: Although some aspects of vestibular schwannoma natural history remain uncertain (pattern of tumor growth, mean tumor growth rate), factors influencing growth such as age at presentation and paracrine factors are well established. Studies focusing on the natural history of hearing have highlighted different patterns of hearing loss and the possible role of intralabyrinthine tumors. The polyclonality of vestibular schwannomas in NF2 was recently unveiled, giving a new perspective to their growth mechanisms. CONCLUSION: An uniform evaluation of tumor growth using volumetric evaluation and hearing with standard classifications will ensure the use of common endpoints and should improve the quality of clinical trials as well as foster comparison among studies while ensuring more consistency in decision-making.

Spinal ependymomas in NF2: a surgical disease?

The management of spinal cord ependymomas in Neurofibromatosis Type 2 (NF2) has traditionally been conservative, in contrast to the management of sporadic cases; the assumption being that, in the context of NF2, they did not cause morbidity. With modern management and improved outcome of other NF2 tumours, this assumption, and therefore the lack of role for surgery, has been questioned. To compare the outcome of conservative treatment of spinal ependymomas in NF2 with surgical intervention in selected patients. Retrospective review at two NF2 centers, Manchester, UK and Paris/Lille, France. In Manchester patients were managed conservatively. In France surgery was a treatment option. Inclusion in the study was based on tumor length of greater than 1.5 cm. The primary parameter assessed was acquired neurological deficit measured by the Modified McCormick Outcome Score. 24 patients from Manchester and 46 patients from France were analyzed. From Manchester, 27% of these patients deteriorated during the course of follow-up. This effectively represents the natural history of ependymomas in NF2. Of the surgical cases, 23% deteriorated postoperatively, but only 2/18 (11%) of those operated on in the NF2 specialist centers. Comparison of the two specialist centers Manchester/France showed a significantly improved outcome (P = 0.012, χ2 test) in the actively surgical center. Spinal ependymomas produce morbidity. Surgery can prevent or improve this in selected cases but can itself can produce morbidity. Surgery should be considered in growing/symptomatic ependymomas, particularly in the absence of overwhelming tumor load where bevacizumab is the preferred option.

Evaluation of the impact of hearing loss in adults: Validation of a quality of life questionnaire.

OBJECTIVES: The impact of hearing loss and of auditory rehabilitation (hearing aid, cochlear implant) on quality of life is a crucial issue. Commonly used questionnaires to assess quality of life in these patients (Nijmegen, APHAB, GBI) are time-consuming, difficult for patients to fill out, and show poor sensitivity to small improvements or deterioration. The objective of the present study was to validate a dedicated quality of life scale for hearing-impaired adults with or without auditory rehabilitation. MATERIAL AND METHODS: ERSA (Évaluation du Retentissement de la Surdité chez l'Adulte: Evaluation of the Impact of Hearing Loss in Adults) is a self-administered questionnaire. It is divided into 4 domains, each comprising 5 questions graded from 1 to 10. The questions are simple, and formulated so patients will answer according to how they feel at the actual time of the session. Test-retest reliability was measured in 38 patients. Internal coherence and validity against the APHAB questionnaire as gold standard and in relation to hearing performance were measured in 122 patients at auditory assessment. Sensitivity to change in hearing was measured in 36 cochlear implant patients, before and 6 or 12 months after implantation. RESULTS: Test-retest reliability was very satisfactory (ρ=0.88). Internal coherence was good for all questions. External validity, comparing ERSA to APHAB scores in the same non-implanted hearing-impaired patients, was good (ρ=0.52). Additionally, ERSA scores correlated with hearing performance in adverse conditions (monosyllabic words: ρ=0.22; sentences in noise: ρ=0.19). In patients tested before and after cochlear implantation, improvement in hearing performance in silence and in noise correlated with an improvement in ERSA score (ρ=0.37 to 0.59, depending on the test), but not to GBI score. CONCLUSION: The ERSA questionnaire is easy and quick to use, reliable, and sensitive to change in hearing performance after cochlear implantation.

Vagal and recurrent laryngeal nerves neuromonitoring during thyroidectomy and parathyroidectomy: A prospective study.

OBJECTIVES: The aim of the study was to stimulate the vagal and the recurrent laryngeal nerves during and after thyroidectomy or parathyroidectomy, to record muscle responses, interpret the electrophysiological modifications and identify prognostic factors for postoperative vocal fold mobility. PATIENTS AND METHODS: A prospective study monitored 151 vagal nerves and 144 recurrent laryngeal nerves in 114 patients. Seven patients (14 vagal nerves) underwent continuous monitoring via an automatic periodic stimulation (APS®) electrode. In 15 patients (21 vagal nerves), the stimulation threshold was studied. Muscle response was recorded on direct vagal and/or recurrent laryngeal nerve stimulation by a monopolar electrode or direct repeated stimulation via an electrode on the vagal nerve. In case of signal attenuation on the first operated side, surgery was not extended to the contralateral side. RESULTS: The vagal nerve stimulation checked inferior laryngeal nerve integrity and recurrent status, without risk of false negatives. The vagal nerve stimulation threshold, before and after dissection, that induced a muscle response of at least 100µV ranged from 0.1 to 0.8mA. Similarity between pre- and post-dissection responses to supramaximal stimulation, defined as 1mA, on the one hand, and between post-dissection vagal and laryngeal recurrent nerve responses on the other correlated with normal postoperative vocal cord mobility. Conversely, muscle response attenuation below 100µV and increased latency indicated a risk of vocal fold palsy. CONCLUSION: Vagal nerve stimulation allows suspicion or elimination of lesions on the inferior laryngeal nerve upstream of the stimulation point and detection of non-recurrent inferior laryngeal nerve. Intermittent monitoring assesses nerve function at the moment of stimulation, while continuous monitoring detects the first signs of nerve injury liable to induce postoperative recurrent nerve palsy. When total thyroidectomy is indicated, signal attenuation on the first operated side casts doubt on continuing surgery to the contralateral side in the same step.

Anatomical, functional and quality-of-life results for mastoid and epitympanic obliteration with bioactive glass s53p4: a prospective clinical study.

OBJECTIVE: To analyse the anatomical, functional and quality-of-life results when using bioactive glass in mastoid and epitympanic obliteration. DESIGN: Prospective clinical study. SETTING: Tertiary referral centre. PARTICIPANTS: Forty-one cases (39 patients) operated between May 2013 and January 2015. MAIN OUTCOME MEASURES: Anatomical results were evaluated by otomicroscopy 1 year after surgery and using imaging to detect residual disease. Functional results were studied by postoperative hearing gain. Quality of life was assessed with the Glasgow Benefit Inventory questionnaire and the success of surgery by a surgery-specific questionnaire. RESULTS: At 1 year, all patients presented a well-healed external auditory canal, with an intact tympanic membrane. In cases with cholesteatoma (n = 23), no recurrent retraction pockets or residual disease were observed on imaging studies. The overall air-bone gap closure was 7.7 ± 1.84 dB (mean ± se of the mean, P < 0.001, paired t-test). No significant differences were found on hearing results when comparing primary versus revision surgery, canal-wall-up versus canal-wall-down obliterations, type of tympanoplasty and presence of cholesteatoma (multifactor anova). The Glasgow Benefit Inventory improved with an average score of 28 and the success of surgery questionnaire showed a significant improvement in ear discharge and a moderate improvement in hearing and equilibrium. CONCLUSIONS: The use of bioactive glass for mastoid and epitympanic obliteration in canal-wall-down or canal-wall-up tympanoplasties is an effective procedure in both primary and revision surgery. The anatomical and functional results appear to be well correlated with patient experience and to the improvement in quality of life.

Safety and effectiveness of the Bonebridge transcutaneous active direct-drive bone-conduction hearing implant at 1-year device use.

The objective of this study is to evaluate the safety and efficacy of a new transcutaneous bone-conduction implant (BCI BB) in patients with conductive and mixed hearing loss or with single-sided deafness (SSD), 1 year after surgical implantation. The study design is multicentric prospective, intra-subject measurements. Each subject is his/her own control. The setting is nine university hospitals: 7 French and 2 Belgian. Sixteen subjects with conductive or mixed hearing loss with bone-conduction hearing thresholds under the upper limit of 45 dB HL for each frequency from 500 to 4000 Hz, and 12 subjects with SSD (contralateral hearing within normal range) were enrolled in the study. All subjects were older than 18 years. The intervention is rehabilitative. The main outcome measure is the evaluation of skin safety, audiological measurements, benefit, and satisfaction questionnaires with a 1-year follow up. Skin safety was rated as good or very good. For the mixed or conductive hearing loss groups, the average functional gain (at 500 Hz, 1, 2, 4 kHz) was 26.1 dB HL (SD 13.7), and mean percentage of speech recognition in quiet at 65 dB was 95 % (vs 74 % unaided). In 5/6 SSD subjects, values of SRT in noise were lower with BB. Questionnaires revealed patient benefit and satisfaction. The transcutaneous BCI is very well tolerated at 1-year follow up, improves audiometric thresholds and intelligibility for speech in quiet and noise, and gives satisfaction to both patients with mixed and conductive hearing loss and patients with SSD.

3D curved multiplanar cone beam CT reconstruction for intracochlear position assessment of straight electrodes array. A temporal bone and clinical study.

A retrospective review of post-op cone beam CT (CBCT) of 8 adult patients and 14 fresh temporal bones that underwent cochlear implantation with straight flexible electrodes array was performed to determine if the position of a long and flexible electrodes array within the cochlear scalae could be reliably assessed with CBCT. An oto-radiologist and two otologists examined the images and assessed the electrodes position. The temporal bone specimens underwent histological analysis for confirm the exact position. The position of the electrodes was rated as scala tympani, scala vestibule, or intermediate position for the electrodes at 180°, 360° and for the apical electrode. In the patient group, for the electrodes at 180° all observers agreed for scala tympani position except for 1 evaluation, while a discrepancy in 3 patients both for the 360° and for the apical electrode assessment were found. In five temporal bones the evaluations were in discrepancy for the 180° electrode, while at 360° a disagreement between raters on the scalar positioning was seen in six temporal bones. A higher discrepancy between was found in assessment of the scalar position of the apical electrode (average pairwise agreement 45.4%, Fleiss k = 0.13). A good concordance was found between the histological results and the consensus between raters for the electrodes in the basal turn, while low agreement (Cohen's k 0.31, pairwise agreement 50%) was found in the identification of the apical electrode position confirming the difficulty to correct identify the electrode position in the second cochlear turn in temporal bones. In conclusion, CBCT is a reliable radiologic exam to correctly evaluate the position of a lateral wall flexible array in implanted patients using the proposed imaging reconstruction method, while some artefacts impede exact evaluation of the position of the apical electrode in temporal bone and other radiological techniques should be preferred in ex vivo studies.

Surgical treatment of sporadic vestibular schwannoma in a series of 1006 patients.

The management of sporadic vestibular schwannoma (VS) has evolved in the last decades. The aim of this study was to analyse the evolution in surgical outcomes of VSs operated by a neurotological team between 1990 and 2006 by different approaches. A monocentric retrospective review of medical charts of 1006 patients was performed. In order to assess eventual changes and progress, the 17-years period was divided in three periods, each one comprehending 268 VS (1990-1996), 299 VS (1997-2001), and 439 VS (2002-2006). Mean follow-up was 5.9 ± 2.4 years. Overall, complete VS removal was achieved in 99.4% of cases. Mortality rate was 0.3%, meningitis and CSF leaks were observed in 1.2 % and 9 % of the cases, respectively. CSF leakage decreased from 11.6% to 7.1% between the first and last period (p < 0.01) as well as revision surgery from 3.4 % to 0.9 % (p < 0.05). Facial nerve was anatomically preserved in 97.7% of cases. At one year, a good facial nerve function was observed in 85.1% of patients (grade I and II of House-Brackmann grading scale), which ranged between the first and last period from 78.4% to 87.6% (p <0.05). At one year, hearing preservation was obtained in 61.6% of patients, which increased from the first period to the last one from 50.9% to 69.0% (p < 0.05) (class A+B+C from the AAO-HNS classification). Useful hearing (class A+B) was observed in 33.5% of cases overall, with 21.8% and 42% in the first and last period, respectively (p < 0.01). Surgical outcomes of sporadic vestibular schwannoma have improved concerning facial nerve function outcomes, hearing preservation and cerebrospinal fluid (CSF) leaks, mainly due to the neuro-otological team's experience. Functional results after complete microsurgical removal of large VS depend on experience gained on small VS removal.

Benefit of contralateral hearing aid in adult cochlear implant bearers.

OBJECTIVES: The present study assessed the interest of a contralateral hearing aid (HA) in adult cochlear implant (CI) bearers. MATERIAL AND METHODS: The study recruited 10 French-speaking adult HA bearers with postlingual bilateral hearing loss, fitted for at least 2 years with a unilateral CI after loss of benefit from HA in one ear but continuing to use their contralateral HA: 4 male, 6 female; mean age, 58 years. All had regularly used bilateral HAs prior to CI. Audiometric assessment comprised: (1) individual ear hearing assessment on pure-tone audiometry and speech discrimination; and (2) free-field testing without aid, with CI only, with HA only and with CI plus HA, on pure-tone audiometry and speech discrimination with quiet background and on speech discrimination in noise. RESULTS: Speech discrimination was significantly improved in the bimodal condition (CI plus HA) as compared to CI alone, on all tests. In quiet, discrimination for disyllabic words was>50% in 7 cases with HA alone, in 2 cases with CI alone and in 1 case in with HA+CI. Under 0dB signal-to-noise ratio, discrimination was>50% in 1 case with HA alone, in 3 cases with CI alone and in 6 cases with HA+CI. CONCLUSION: The present results showed benefit in auditory perception in quiet and in noise with bimodal stimulation. When there is residual hearing in the non-implanted ear, a HA should be fitted; and in progressive bilateral hearing loss, CI should be suggested when HA benefit decreases in one ear.

The pathophysiology of otosclerosis: Review of current research.

Otosclerosis is a complex disease of the human otic capsule with highest incidence in adult Caucasians. So far, many possible etiological factors like genetics, HLA, autoimmunity, viruses, inflammation, and hormones have been investigated but still the development of the disease remains unclear. Currently, the surgical replacement of stapes (stapedotomy) remains the best possible treatment option. In this review, we analyze different etiological factors studied so far in otosclerosis pathophysiology and discuss most recent findings and possible new research pathways.

[A report of three cases and review of auditory brainstem implants in children]. / Implantation auditive du tronc cérébral chez l'enfant. À propos de trois cas.

AIM OF THE STUDY: To present three pediatric cases of auditory brainstem implantation (ABI) and review literature data concerning this topic. PATIENTS: The first two children had a neurofibromatosis type II with bilateral sensorineural deafness; in both cases, the implant was inserted during the surgical removal of a vestibular schwannoma; the third patient had profound deafness due to bilateral cochlear nerve insufficiency associated with inner ear malformation. RESULTS: Two postoperative complications were observed: patient 1 had a persistent fever which required the replacement of the fat graft used to seal the translabyrinthine approach; patient 3 had a CSF leakage requiring additional surgery and lumbar external drainage. In our three patients, the numbers of active electrodes were 6/22 (Cochlear ABI 24M ABI), 11/12 (Medel Opus II ABI) and 11/12 (implant Medel), respectively. Due to additional major surgical procedures and to disappointing functional results of the ABI, patient 1 stopped wearing her implant 18 months after implantation. Nine months after surgery, patient 2 achieved open-set speech recognition and was very satisfied with the implant. Six months after implantation, patient 3 (cochlear nerve deficiency), who was 3.5 years-old at the time, clearly reacted to some environmental sounds but was not yet able to achieve speech recognition. CONCLUSIONS: ABI has now entered the list of treatments that can be proposed in pediatric profound sensorineural deafness. Its major risks of complications are CSF leakage and non-auditory side effects. Its outcomes are worse and less predictable than cochlear implants. Thus, its indications must remain restricted to cases meeting the following conditions: absence of alternative option to restore hearing, patients and parents high level of motivation and realistic expectations.

[Cochlear implant in adults]. / Implants cochléaires chez l'adulte.

Cochlear implant in adults is a procedure, dedicated to rehabilitate severe to profound hearing loss. Because of technological progresses and their applications for signal strategies, new devices can improve hearing, even in noise conditions. Binaural stimulation, cochlear implant and hearing aid or bilateral cochlear implants are the best opportunities to access to better level of comprehension in all conditions and space localisation. By now minimally invasive surgery is possible to preserve residual hearing and use a double stimulation modality for the same ear: electrical for high frequencies and acoustic for low frequencies. In several conditions, cochlear implant is not possible due to cochlear nerve tumour or major malformations of the inner ear. In these cases, a brainstem implantation can be considered. Clinical data demonstrate that improvement in daily communication, for both cochlear and brainstem implants, is correlated with cerebral activation of auditory cortex.

Intraoperative laryngeal nerve monitoring during thyroidectomy and parathyroidectomy: A prospective study.

OBJECTIVES: The aim of this study was to stimulate the recurrent laryngeal nerve during thyroidectomy or parathyroidectomy and to record the muscle responses in an attempt to predict postoperative vocal fold mobility. PATIENTS AND METHODS: Intraoperative recurrent laryngeal nerve monitoring during general anaesthesia was performed by using an electrode-bearing endotracheal tube (nerve integrity monitor EMG endotracheal tube [Medtronic Xomed, Jacksonville, Flo, USA]). Two hundred and fifteen recurrent laryngeal nerves from 141 patients undergoing total thyroidectomy (n=74), hemithyroidectomy (n=63), or parathyroidectomy (n=4) were prospectively monitored. In each case, the muscle potential was recorded after stimulation of the recurrent laryngeal nerve by a monopolar probe. RESULTS: The nerve stimulation threshold before and after dissection that induced a muscle response of at least 100 µV ranged from 0.1 to 0.85 mA (mean 0.4 mA). The supramaximal stimulation intensity was defined as 1 mA. The amplitude of muscle response varied considerably from one patient to another, but the similarity of the muscle response at supramaximal intensity between pre- and postdissection and between postdissection at the proximal and distal exposed portions of the nerve was correlated with normal postoperative vocal fold function. Inversely, alteration of the muscle response indicated a considerable risk of recurrent laryngeal nerve palsy, but was not predictive of whether or not this lesion would be permanent. CONCLUSIONS: Recurrent laryngeal nerve monitoring with a system using surface electrodes is a simple, non-invasive technique that is just as sensitive as monitoring by intramuscular electrodes. Monitoring is helpful for initial nerve identification and is useful to determine nerve function during and after surgery, and to adapt the surgical strategy accordingly.