Long-term residual hearing in cochlear implanted adult patients who were candidates for electro-acoustic stimulation.

PURPOSE: To evaluate the long-term hearing outcomes in cochlear implanted adults with residual hearing at low frequencies, and the proportion of patients using electro-acoustic stimulation (EAS). METHODS: A monocentric retrospective cohort study was performed in a tertiary referral center. Population demographics, surgical approach, pre- and postoperative hearing at low frequencies, in the implanted and contralateral ear, were recorded as well as duration of EAS use. The percentage hearing preservation was calculated according to the formula S (HEARRING group). RESULTS: In total, 63 adults (81 ears) with residual hearing underwent cochlear implantation with intent to use EAS processors. Six different types of electrode array were implanted. The mean pure tone audiometry (PTA) shift after cochlear implantation was 16 ± 15 dB HL (range 0-59 dB HL). Half of the implanted ears had minimal hearing preservation or total hearing loss (HL) at 5.5 years and the cumulative risk of total HL was 50% at 7 years. During the follow-up, total HL occurred in 22 ears. The decrease in hearing levels was similar in both implanted and contralateral ear during follow-up (ns, F = 2.46 ± 3, Linear Mixed Model (LMM)). Only 44 patients found a benefit from EAS at the first fitting. At the last visit, EAS processors were fitted in 30% of the cases. The pre- and postoperative mean PTA thresholds were not predictive of EAS use (Cox's proportional hazards analysis). CONCLUSIONS: Postoperative residual hearing was observed in 93% of implanted ears, but only half of them had an initial benefit from EAS. No predictive factors were found to influence the use of EAS processors.

Modifications to a 3D-printed temporal bone model for augmented stapes fixation surgery teaching.

Functional outcomes and complications in otosclerosis surgery are governed by the surgeon's experience. Thus, teaching the procedure to residents to guide them through the learning process as quickly as possible is challenging. Artificial 3D-printed temporal bones are replacing cadaver specimens in many institutions to learn mastoidectomy, but these are not suitable for middle ear surgery training. The goal of this work was to adapt such an artificial temporal bone to aid the teaching of otosclerosis surgery and to evaluate this tool. We have modified a commercially available 3D-printed temporal bone by replacing the incus and stapes of the model with in-house 3D-printed ossicles. The incus could be attached to a 6-axis force sensor. The stapes footplate was fenestrated and attached to a 1-axis force sensor. Six junior surgeons (residents) and seven senior surgeons (fellows or consultants) were enrolled to perform piston prosthesis placement and crimping as performed during otosclerosis surgery. The time required to perform the tasks and the forces applied to the incus and stapes were collected and analyzed. No statistically significant differences were observed between the junior and senior groups for time taken to perform the tasks and the forces applied to the incus during crimping and placement of the prosthesis. However, significantly lower forces were applied to the stapes by the senior surgeons in comparison with the junior surgeons during prosthesis placement (junior vs senior group, 328 ± 202.9 vs 80 ± 99.6 mN, p = 0.008) and during prosthesis crimping (junior vs senior group, 565 ± 233 vs 66 ± 48.6 mN, p = 0.02). We have described a new teaching tool for otosclerosis surgery based on the modification of a 3D-printed temporal bone to implement force sensors on the incus and stapes. This tool could be used as a training tool to help the residents to self-evaluate their progress with recording of objective measurements.

Effect of a liposomal hyaluronic acid gel loaded with dexamethasone in a guinea pig model after manual or motorized cochlear implantation.

Goals of cochlear implantation have shifted from complete insertion of the cochlear electrode array towards low traumatic insertion with minimally invasive techniques. The aim of this study was first to evaluate, in a guinea pig model of cochlear implantation, the effect of a motorized insertion technique on hearing preservation. The second goal was to study a new gel formulation containing dexamethasone phosphate loaded in liposomes (DEX-P). Guinea pigs had a unilateral cochlear implantation with either a manual technique (n = 12), or a motorized technique (n = 15), with a 0.4 mm diameter and 4 mm long array trough a cochleostomy. At the end of the procedure, hyaluronic acid gel containing drug-free liposomes, or liposomes loaded with DEX-P, was injected into the bulla. Auditory brainstem responses thresholds were recorded before surgery and day 2 and 7 after surgery. All the animals had increased auditory brainstem responses thresholds after the cochlear implantation. Implanted animals with the motorized insertion tool experienced a partial hearing recovery at day 7 but not in those implanted with the manual insertion procedure (p < 0.001). In the manually implanted animals, a partial recovery was observed when DEX-P contained in liposomal gel was locally administrated (p < 0.0001). Finally, no additive effect with the motorized insertion was noticed. The deleterious effect of manual insertion, during cochlear implantation, can be prevented with local DEX-P administration in the bulla at day 7. The use of a motorized tool performed more atraumatic electrode array insertion for postoperative hearing.

Impact of prophylactic central neck dissection on oncologic outcomes of papillary thyroid carcinoma: a review.

Prophylactic neck dissection (PND) for papillary thyroid carcinoma (PTC) is controversial. Our aim was to assess current levels of evidence (LE) according to the Oxford Centre for Evidence-based Medicine ( http://www.cebm.net/?O=1025 ) regarding the oncologic benefits of PND. Data were analyzed via MEDLINE keywords: PTC, differentiated thyroid carcinoma, PND, central lymph node metastases, central compartment, recurrence-free survival. There was conflicting evidence regarding the rate of reoperation for recurrence, with some studies showing a lower rate after PND with increased recurrence-free survival and a higher rate of undetectable pre- and post-ablation thyroglobulin levels (LE 4), whereas other studies did not show a difference (LE 4). Only one study (LE 4) showed improved disease-specific survival with PND. PND may improve recurrence-free survival, although this is supported by only a low LE. Current recommendations can only be based on low-level evidence.

Influence of prophylactic neck dissection on rate of retreatment for papillary thyroid carcinoma.

BACKGROUND: Prophylactic neck dissection (PND) for papillary thyroid cancer is controversial. The objective of this study was to analyze the influence of PND on the rate of retreatment. METHODS: In this retrospective case-control study, papillary thyroid carcinomas >10 mm without ultrasonographic evidence of nodal disease (cN0) were treated with total thyroidectomy (TT) or TT with bilateral central compartment PND. All received postoperative radioactive iodine ((131)I) and were followed for at least 1 year. We compared the rate of retreatment (surgery or (131)I). RESULTS: Altogether, 246 patients (mean age 46 years, 78 % women) underwent TT (n = 91) or TT + PND (n = 155). The groups were similar in age, sex, tumor size, and follow-up (median 6.3 years) (p > 0.05). Overall, 11 (12 %) of the patients in the TT group underwent reoperation in the central compartment for recurrence versus 3 (2 %) in the TT + PND group (p < 0.001). There were 1.18 administrations of (131)I for the TT group versus 1.08 for the TT + PND group (p = 0.08). The average cumulative dose of (131)I was 3.9 ± 1.8 GBq for the TT group and 3.8 ± 1.3 GBq for the TT + PND group (p = 0.52). Actuarial (Kaplan-Meier) 5-year retreatment rates were 14.7 % in the TT group and 6.5 % in the TT + PND group (p = 0.01, log-rank). The rate of permanent recurrent nerve paralysis was 2 % for the TT group and 1 % for the TT + PND group (p = 0.98). The rates of permanent hypoparathyroidism were 7 versus 3 %, respectively (p = 0.12). CONCLUSIONS: Five-year retreatment rates were lower in patients treated with PND, with no added permanent morbidity.

Profound bilateral deafness complicating aortic arch surgery.

Hearing loss is a rare complication of cardiac surgery; bilateral profound deafness has never been reported in this setting. A 45-year-old male presented with profound bilateral sudden deafness following arch surgery and frozen elephant trunk. Patient's presentation, surgery details and aetiological mechanisms are discussed.

Prospective Multicentric Follow-up Study of Cochlear Implantation in Adults With Single-Sided Deafness: Tinnitus and Audiological Outcomes.

OBJECTIVE: This study investigated the audiological and tinnitus outcomes of cochlear implantation (CI) in adults with single-sided deafness (SSD) and tinnitus. STUDY DESIGN: Multicentered prospective, non-randomized intervention study. SETTING: Six French CI centers. PATIENTS: Twenty-six patients with SSD and incapacitating tinnitus (Tinnitus Handicap Inventory [THI] >58) underwent cochlear implantation. INTERVENTIONS: First, CIs delivered only masking white noise stimulation for 1 month and then standard CI stimulation. MAIN OUTCOME MEASURES: Before and after CI surgery, patients completed the THI, Tinnitus Reaction Questionnaire (TRQ), Subjective Tinnitus Severity Scale (STSS), and two visual analogue scales quantifying tinnitus loudness and annoyance. Speech perception in spatialized noise was tested at 13 months. RESULTS: The first month of white noise stimulation triggered a significant improvement in THI scores (72 ±â€Š9 to 55 ±â€Š20, p < 0.05). No change was observed for the other measures. After 1 year of standard CI stimulation, 23 patients (92%) reported a significant improvement in tinnitus. This improvement started 1 to 2 months after CI and exceeded 40% improvement for 14 patients (54%). Average speech-in-noise perception after 1 year significantly improved for the 23 patients who completed these measures. CONCLUSIONS: CI is efficacious to reduce the handicap of patient with SSD and incapacitating tinnitus, leading to a decrease in reported tinnitus and partial restoration of binaural hearing abilities.

ECAP growth function to increasing pulse amplitude or pulse duration demonstrates large inter-animal variability that is reflected in auditory cortex of the guinea pig.

Despite remarkable advances made to ameliorate how cochlear implants process the acoustic environment, many improvements can still be made. One of most fundamental questions concerns a strategy to simulate an increase in sound intensity. Psychoacoustic studies indicated that acting on either the current, or the duration of the stimulating pulses leads to perception of changes in how loud the sound is. The present study compared the growth function of electrically evoked Compound Action Potentials (eCAP) of the 8th nerve using these two strategies to increase electrical charges (and potentially to increase the sound intensity). Both with chronically (experiment 1) or acutely (experiment 2) implanted guinea pigs, only a few differences were observed between the mean eCAP amplitude growth functions obtained with the two strategies. However, both in chronic and acute experiments, many animals showed larger increases of eCAP amplitude with current increase, whereas some animals showed larger of eCAP amplitude with duration increase, and other animals show no difference between either approaches. This indicates that the parameters allowing the largest increase in eCAP amplitude considerably differ between subjects. In addition, there was a significant correlation between the strength of neuronal firing rate in auditory cortex and the effect of these two strategies on the eCAP amplitude. This suggests that pre-selecting only one strategy for recruiting auditory nerve fibers in a given subject might not be appropriate for all human subjects.

Assessment of the efficacy of a local steroid rescue treatment administered 2 days after a moderate noise-induced trauma in guinea pig.

OBJECTIVES: Intratympanic injection of corticosteroids membrane after noise-induced hearing loss is an accepted alternative to general administration. We investigated the effect on hearing of a hyaluronic acid gel with liposomes loaded with dexamethasone (DexP) administered into the middle ear. METHODS: An acute acoustic trauma was performed to 13 guinea pigs for a period of 1 h on Day -2. Two 2 days after the noise trauma, the animals were then assigned randomly to four experimental groups: control without gel, gel injection, gel-containing free DexP, gel-containing DexP loaded into liposomes. Auditory thresholds were measured with Auditory Brainstem Response before Day -2 and at Day 0, Day 7 and Day 30 after noise trauma. RESULTS: Seven days after, a complete hearing recovery was observed in the control group at all frequencies apart from 8 kHz, and no recovery was observed in the three groups receiving a gel injection. Thirty days after trauma, all of the animals had recovered normal hearing, apart from at the 8-kHz frequency, with similar auditory thresholds. CONCLUSIONS: Local DexP administration 48 h after a mild acoustic trauma did not improve hearing recovery, even with a sustained release in a specific gel formulation designed for inner ear therapy.

Hearing impairment in patients with myotonic dystrophy type 2.

OBJECTIVE: To systematically assess auditory characteristics of a large cohort of patients with genetically confirmed myotonic dystrophy type 2 (DM2). METHODS: Patients with DM2 were included prospectively in an international cross-sectional study. A structured interview about hearing symptoms was held. Thereafter, standardized otologic examination, pure tone audiometry (PTA; 0.25, 0.5, 1, 2, 4, and 8 kHz), speech audiometry, tympanometry, acoustic middle ear muscle reflexes, and brainstem auditory evoked potentials (BAEP) were performed. The ISO 7029 standard was used to compare the PTA results with established hearing thresholds of the general population according to sex and age. RESULTS: Thirty-one Dutch and 25 French patients with DM2 (61% female) were included with a mean age of 57 years (range 31-78). The median hearing threshold of the DM2 cohort was higher for all measured frequencies, compared to the 50th percentile of normal (p < 0.001). Hearing impairment was mild in 39%, moderate in 21%, and severe in 2% of patients with DM2. The absence of an air-bone gap with PTA, concordant results of speech audiometry with PTA, and normal findings of BAEP suggest that the sensorineural hearing impairment is located in the cochlea. A significant correlation was found between hearing impairment and age, even when corrected for presbycusis. CONCLUSIONS: Cochlear sensorineural hearing impairment is a frequent symptom in patients with DM2, suggesting an early presbycusis. Therefore, we recommend informing about hearing impairment and readily performing audiometry when hearing impairment is suspected in order to propose early hearing rehabilitation with hearing aids when indicated.

Influence of electrode array stiffness and diameter on hearing in cochlear implanted guinea pig.

During cochlear implantation, electrode array translocation and trauma should be avoided to preserve residual hearing. The aim of our study was to evaluate the effect of physical parameters of the array on residual hearing and cochlear structures during insertion. Three array prototypes with different stiffnesses or external diameters were implanted in normal hearing guinea pigs via a motorized insertion tool carried on a robot-based arm, and insertion forces were recorded. Array prototypes 0.4 and 0.4R had 0.4 mm external diameter and prototype 0.3 had 0.3 mm external diameter. The axial stiffness was set to 1 for the 0.4 prototype and the stiffnesses of the 0.4R and 0.3 prototypes were calculated from this as 6.8 and 0.8 (relative units), respectively. Hearing was assessed preoperatively by the auditory brainstem response (ABR), and then at day 7 and day 30 post-implantation. A study of the macroscopic anatomy was performed on cochleae harvested at day 30 to examine the scala location of the array. At day 7, guinea pigs implanted with the 0.4R array had significantly poorer hearing results than those implanted with the 0.3 array (26±17.7, 44±23.4, 33±20.5 dB, n = 7, vs 5±8.7, 1±11.6, 12±11.5 dB, n = 6, mean±SEM, respectively, at 8, 16 and 24 kHz, p<0.01) or those implanted with the 0.4 array (44±23.4 dB, n = 7, vs 28±21.7 dB, n = 7, at 16 kHz, p<0.05). Hearing remained stable from day 7 to day 30. The maximal peak of insertion force was higher with the 0.4R array than with the 0.3 array (56±23.8 mN, n = 7, vs 26±8.7 mN, n = 6). Observation of the cochleae showed that an incorrectly positioned electrode array or fibrosis were associated with hearing loss ≥40 dB (at 16 kHz). An optimal position in the scala tympani with a flexible and thin array and prevention of fibrosis should be the primary objectives to preserve hearing during cochlear implantation.

Hyaluronic acid liposomal gel sustains delivery of a corticoid to the inner ear.

The inner ear is one of the most challenging organs for drug delivery, mainly because of the blood-perilymph barrier. Therefore, local rather than systemic drug delivery methods are being developed for inner ear therapy. In this work, we have evaluated the benefit of a hyaluronic acid liposomal gel for sustained delivery of a corticoid to the inner ear after local injection into the middle ear in a guinea pig model. The liposomal gel was easily injectable as a result of the shear-thinning behavior of hyaluronic acid. A prolonged residence time at the site of injection as well as in the round window were achieved without any negative effect on the hearing thresholds of the animals. The presence of liposomes in the formulation resulted in sustained release of the drug in the perilymph for 30days and promoted the conversion of the prodrug loaded within the liposomes (dexamethasone phosphate) into its active form (dexamethasone). In this way, therapeutic doses were attained in the perilymph. A small amount of intact liposomes was visualized in the perilymph, whereas the main proportion of liposomes seemed to be trapped in the round window resulting in a reservoir effect. Thus, the administration of hyaluronic acid liposomal gel to the middle ear is an efficient strategy for delivering corticoids to the inner ear in a sustained manner.

Recent advances in local drug delivery to the inner ear.

Inner ear diseases are not adequately treated by systemic drug administration mainly because of the blood-perilymph barrier that reduces exchanges between plasma and inner ear fluids. Local drug delivery methods including intratympanic and intracochlear administrations are currently developed to treat inner ear disorders more efficiently. Intratympanic administration is minimally invasive but relies on diffusion through middle ear barriers for drug entry into the cochlea, whereas intracochlear administration offers direct access to the colchlea but is rather invasive. A wide range of drug delivery systems or devices were evaluated in research and clinic over the last decade for inner ear applications. In this review, different strategies including medical devices, hydrogels and nanoparticulate systems for intratympanic administration, and cochlear implant coating or advanced medical devices for intracoclear administration were explored with special attention to in vivo studies. This review highlights the promising systems for future clinical applications as well as the current hurdles that remain to be overcome for efficient inner ear therapy.

Supramaximal stimulation during intraoperative facial nerve monitoring as a simple parameter to predict early functional outcome after parotidectomy.

CONCLUSION: A supramaximal stimulation at 2 mA during intraoperative electromyographic (EMG) facial nerve monitoring appears to be a simple and effective parameter to predict immediate postoperative injury. OBJECTIVES: To assess the role of systematic intraoperative facial nerve monitoring in predicting the early functional outcomes obtained after parotidectomy. METHODS: Data were collected from patients who underwent parotidectomy. Intraoperative EMG monitoring of the facial nerve was performed by registering two parameters, event intensity (>100 µV) and amplitude of response after a supramaximal stimulation at 2 mA, at the beginning and end of gland removal. Early postoperative clinical functional facial nerve disorder was assessed at day 2. RESULTS: Overall, 50 patients were included and an early facial dysfunction was detected in 27 cases (54%). The maximal response amplitude after supramaximal stimulation at the trunk of the facial nerve was higher in patients with normal facial function compared with those with poor outcomes at the end of surgery (p < 0.01). The postdissection to predissection ratios of maximal response amplitude, but not the stimulation thresholds, were indicative of a nerve conduction block and were significantly lower in the patient group with a poor outcome compared with the group with a normal facial outcome (p < 0.02).