Anatomic variations of the round window niche: radiological study and related endoscopic anatomy.

PURPOSE: In the last decades, literature has shown an increasing interest in round windows (RW) anatomy due to its pivotal role in deafness surgery. The high variability of this anatomical region, with particular regard to the round windows niche (RWN), has been studied by several authors through different methods of investigation. The aim of the present research was to radiologically examine the morphological variability of the RWN and to link the imaging findings to the endoscopic view. METHODS: High-resolution CT scans of 300 temporal bones without neuro-otological pathologies were retrospectively reviewed by 2 neuroradiologist and 1 ENT surgeon who independently evaluated the RWN morphological variations. To link the radiological to the endoscopic data, 45 cadaveric human temporal bones were submitted to a radiological evaluation and to an otoendoscopy conducted through a posterior tympanotomy approach. RESULTS: Three variants of the RWN were detected on coronal CT scan reconstructions: 155 "cylindrical-type", 97 "j-type" and 48 "truncated cone-type". For each radiological type the endoscopic findings showed a specific endoscopic position of the RW chamber, which results in different degrees of RW membrane visibility when analysed through a posterior tympanotomy approach. CONCLUSIONS: To the best of our knowledge, this is the first description of the above-mentioned RWN radiological variations supported by endoscopic data. This study suggests an additional anatomical evaluation that could be useful to predict the RW membrane visibility through a posterior tympanotomy approach. Further studies are required to support the clinical implications of our observations.

Implantable hearing devices in clinical practice. Systematic review and consensus statements.

Objective: Implantable hearing devices represent a modern and innovative solution for hearing restoration. Over the years, these high-tech devices have increasingly evolved but their use in clinical practice is not universally agreed in the scientific literature. Congresses, meetings, conferences, and consensus statements to achieve international agreement have been made. This work follows this line and aims to answer unsolved questions regarding examinations, selection criteria and surgery for implantable hearing devices. Materials and methods: A Consensus Working Group was established by the Italian Society of Otorhinolaryngology. A method group performed a systematic review for each single question to identify the current best evidence on the topic and to guide a multidisciplinary panel in developing the statements. Results: Twenty-nine consensus statements were approved by the Italian Society of Otorhinolaryngology. These were associated with 4 key area subtopics regarding pre-operative tests, otological, audiological and surgical indications. Conclusions: This consensus can be considered a further step forward to establish realistic guidelines on the debated topic of implantable hearing devices.

Retrosigmoidal placement of an active transcutaneous bone conduction implant: surgical and audiological perspectives in a multicentre study.

INTRODUCTION: The retrosigmoidal (RS) placement of the Bonebridge system (BB) has been advocated for cases of unfavourable anatomical or clinical conditions which contraindicate transmastoid-presigmoidal positioning. However, these disadvantageous conditions, combined with the considerable dimensions of the implant, may represent a challenge, especially for surgeons with no skull base experience. Moreover, the literature reports only limited experience concerning RS implantation of the BB system. METHODS: A multicentre, retrospective study was conducted to analyse the surgical and functional outcomes of a wide population of patients undergoing RS placement of the BB system by means of a surgical technique specifically developed to overcome the intraoperative issues related to this surgery. Twenty patients with conductive or mixed hearing loss and single sided deafness were submitted to RS implantation of the BB system. RESULTS: Audiological assessment concerning the measurement of the functional and effective gain by pure-tone audiometry (28 dB HL and -12.25 dB HL, respectively) and speech audiometry (24.7 dB HL and -21 dB HL, respectively) was conducted. A high overall subjective improvement of quality of life was recorded with the Glasgow Benefit Inventory questionnaire. No major complications, such as device extrusions or other conditions requiring revision surgery, were reported during the follow-up period (median: 42 months). CONCLUSIONS: In our study, which has one of the largest cohort of patients reported in the literature, RS placement of the BB system was safe and effective. Our functional results showed comparable hearing outcomes with presigmoidal placement. The effective gain, rarely investigated in this field, may be the object of further research to improve our understanding of bone conduction mechanisms exploited by bone conduction hearing implants.

Hearing again with two ears: recovery of spatial hearing after bilateral cochlear implantation.

Bilateral cochlear implants (CI) offer a unique opportunity for the study of spatial hearing plasticity in humans. Here we studied the recovery of spatial hearing in two sequential bilateral CI recipients, adopting a longitudinal approach. Each recipient was tested in a sound-source identification task shortly after bilateral activation and at 1, 6, and 12 months follow-up. The results show fast recovery (1 month from CI activation) in the recipient who had substantial experience with auditory cues in adulthood. By contrast, the bilateral CI recipient who developed profound deafness in childhood, regained spatial hearing abilities only 12 months after CI activation. These findings provide the first direct evidence that recovery of auditory spatial abilities in bilateral CI recipients can occur shortly after activation of the two devices. In addition, they suggest that previous auditory experience can constrain the time course of this recovery.

Treatment of moderate-to-severe otosclerosis with simultaneous piston surgery and incus vibroplasty.

OBJECTIVE: Whereas the nature of otosclerosis has been extensively investigated, treatment modalities in advanced otosclerosis with the sensorineural hearing loss (SNHL) are relatively unexplored. MATERIALS AND METHODS: This article presents a retrospective case series study of nine patients who received a one-stage piston coupled with Vibrant Soundbridge® vibroplasty in treating otosclerosis with moderate-to-severe SNHL. RESULTS: The findings suggest that hearing loss could be restored across frequencies and no significant change in the bone-conduction threshold were measured. CONCLUSION: One-stage piston surgery coupled with incus vibroplasty is a safe procedure and has sufficient efficacy to restore hearing loss in patients with otosclerosis with moderate-to-severe SNHL.

Double posterior labyrinthotomy technique: results in three Med-El patients with common cavity.

HYPOTHESIS: This study reports on the use of the double posterior labyrinthotomy surgical technique and a custom-designed electrode to ensure better positioning of stimulating electrodes within the common cavity and thus demonstrate suitable outcomes in patients. BACKGROUND: Cochlear implantation has proven beneficial for numerous children with congenital malformations of the inner ear. Several studies show good auditory perception outcomes in children with common cavity. However, there have been risks involved with surgical techniques used in the actual implantation. These include possible aberrant facial nerve and the strong potential for a cerebrospinal fluid gusher. Improved surgical techniques and electrode design could allow for better electrode contact and avoid electrode placement in the internal auditory meatus. METHOD: The double posterior labyrinthotomy technique was carried out in three cases using a custom made MED-EL COMBI 40+ electrode. RESULTS: Surgery was carried out with no complications and is no more technically demanding than other standard surgical approaches. The speech processor program remains stable over time, and auditory perception results are similar to those obtained from children with no cochlear abnormalities. CONCLUSION: These results demonstrate the success of the double posterior labyrinthotomy approach with modified cochlear implant, and this could be recommended as the procedure of choice in children presenting to an implant team with a common cavity.

Common cavity and custom-made electrodes: speech perception and audiological performance of children with common cavity implanted with a custom-made MED-EL electrode.

OBJECTIVE: Few studies exist on children with common cavity, fewer still on their long-term audiological development after having received a cochlear implant. Our goal was to observe and report the long-term audiological progress of children with common cavity who were implanted with a custom-made electrode. METHODS: In this longitudinal, multi-center study, 19 children were implanted with a MED-EL custom-made electrode via either single slit cochleostomy or double posterior labyrinthotomy. We observed their audiological development with a test battery consisting of Categories of Auditory Performance (CAP), Speech Intelligibility Rating (SIR), and Ling 6-Sounds tests. We tested the children 1 month prior to the surgery; at first fitting; at 1, 3, 6, 12, and 18 months post first-fitting; at 2 years after first-fitting; and, whenever possible, at 3, 4, and 5 years after first-fitting. RESULTS: Children with common cavity tend to steadily and significantly improve their audiological skills over time. This development may, however, be highly individual; probably in part due to relatively high levels of additional needs. Parents should be counseled to establish realistic post-implantation expectations. Surgically, contrary to our expectations, we cannot confirm that double posterior labyrinthotomy reduces intracochlear electrode movement or that the MED-EL custom electrode leads to fewer incidences of intra- or post-implantation complications. CONCLUSIONS: Cochlear implantation is a safe and effective treatment option in children with common cavity. The majority of children with CC derive significant audiological benefit from implantation. Intra- and post-surgical complications, while serious, and be dealt with effectively in most cases.

Simultaneous Vibrant Soundbridge Implantation and 2nd Stage Auricular Reconstruction for Microtia with Aural Atresia.

Aural atresia and severe microtia are associated malformations that result in problems with hearing and cosmesis, associated speech and language difficulties and diminished self-esteem. In cases where middle ear ossiculoplasty and aural atresia canalplasty are expected to give poor hearing outcomes that would eventually require the use of hearing aids, bone anchored hearing aids or active middle ear implants may be better options. This case report describes a simultaneous Vibrant Soundbridge implantation and 2(nd) stage auricular reconstruction with rib graft cartilage for an 11-year-old boy with grade III microtia and aural atresia 8 months after the 1(st) stage reconstruction. Audiometric results of the Vibrant Soundbridge aided ear were comparable to that of the contralateral hearing aid aided ear.

Application of the Vibrant Soundbridge in bilateral congenital atresia in toddlers.

CONCLUSION: The Vibrant Soundbridge offers an excellent audiologic rehabilitation for toddlers with microtia and atresia. It provides direct stimulation of the cochlea and straightforward adaption to the given anatomical structures. The 'posterior atresia incision' preserves the physical integrity of the tissue layers around the ear remnant, which is essential for an aesthetic auricular reconstruction. OBJECTIVES: Patients with bilateral aural atresia require immediate auditory stimulation to ensure normal speech development. We present an operative technique that allows safe restoration of hearing before aesthetic reconstruction. METHODS: A 6-year-old boy presented with bilateral microtia and osseous atresia. A hairline incision was performed through all layers and was followed by a subperiostal preparation towards the atresia plane. The fused malleus-incus-complex was removed and the transducer was crimped to the stapes suprastructure on both sides. RESULTS: Speech performance is nearly normal in both quiet and noise conditions. The surgery did not affect the tissues that are important for the later ear reconstruction.

Application of the Vibrant Soundbridge to unilateral osseous atresia cases.

OBJECTIVES/HYPOTHESIS: Patients with high-grade atresia-microtia suffer from a combined malformation of the outer and middle ears, typically leading to a severe hearing impairment. Long-term results of middle ear reconstruction with tympanoplasty are often insufficient due to persistent air-bone gaps, and new techniques in hearing rehabilitation are required. The objective of this research is to evaluate the active middle ear implant, the Vibrant Soundbridge (VSB), for hearing rehabilitation of patients with unilateral osseous aural atresia. STUDY DESIGN: Prospective analysis of a consecutive cohort of seven atresia patients (mean age = 15 years). METHODS: During plastic auricular reconstruction of unilateral atresia-microtia cases, an access through the bony atresia plate was drilled. The floating mass transducer was coupled to the stapes (or remaining stapes suprastructure), ossicular chain, or round window, depending on the anatomic needs of the patient. Audiometric testing, including pure-tone thresholds, and speech testing in quiet and noise were performed. RESULTS: : The mean threshold with the VSB activated in the free field warble tone audiometry was 23.8 dB hearing level (HL). Mean functional gain was 45.5 dB HL. Mean aided free field speech discrimination in quiet was 64% at 50 dB, 99% at 65 dB, and 100% at 80 dB. CONCLUSIONS: By circumventing the malformed middle ear and directly stimulating the cochlea, the VSB provides a new rehabilitation option for atresia patients. We conclude that the procedure is safe and effective and can be implemented in combination with outer ear reconstruction.

Spatial hearing with a single cochlear implant in late-implanted adults.

We assessed sound localisation abilities of late-implanted adults fitted with a single cochlear implant (CI) and examined whether these abilities are affected by the duration of implant use. Ten prelingually and four postlingually deafened adults who received a unilateral CI were tested in a sound-source identification task. Above chance performance was observed in those prelingual CI recipients who had worn their implant for longer time (9 years on average), revealing some monaural sound localisation abilities in this population but only after extensive CI use. On the contrary, the four postlingual recipients performed equal or better with respect to the best prelingual participants despite shorter experience with the monaural implant (11 months on average). Our findings reveal that some sound localisation ability can emerge in prelingually deafened adults fitted with a single implant, at least in a controlled laboratory setting. This ability, however, appears to emerge only after several years of CI use. Furthermore, the results of four postlingually deafened adults suggest that early experience with auditory cues may result in more rapid acquisition of spatial hearing with a single CI.

Change blindness in profoundly deaf individuals and cochlear implant recipients.

We used a change blindness paradigm to examine visual abilities in the profoundly deaf when exogenous capture of attention is prevented and only endogenous attention shifts are possible. Nineteen profoundly deaf participants, 22 cochlear implant recipients and 18 hearing controls were asked to detect a change occurring between two consecutive visual scenes separated by a blank. Changes occurred on half of the trials, either at central or peripheral locations, and the task was performed under focused attention (at the centre or at the periphery) or under distributed attention. When allowed to focus attention, all groups showed comparable change sensitivity, with better performance for central than peripheral stimuli. However, in the distributed condition, only the profoundly deaf participants remained reliably more sensitive to changes occurring at central than peripheral locations. This finding contradicts the well-known visual performance enhancement typically observed for peripheral regions of the visual field in the profoundly deaf. We suggest that this discrepancy between our novel finding and the existing literature reflects the strictly endogenous nature of our change blindness paradigm. Our results point to a differential role of exogenous and endogenous attention components in the multisensory plasticity occurring after auditory deprivation and suggest that compensatory abilities in the deaf may be linked to exogenous capture of visual attention.