Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep.

Severe visual impairment can result from retinal degenerative diseases such as retinitis pigmentosa, which lead to photoreceptor cell death. These pathologies result in extensive neural and glial remodelling, with survival of excitable retinal neurons that can be electrically stimulated to elicit visual percepts and restore a form of useful vision. The Phoenix99 Bionic Eye is a fully implantable visual prosthesis, designed to stimulate the retina from the suprachoroidal space. In the current study, nine passive devices were implanted in an ovine model from two days to three months. The impact of the intervention and implant stability were assessed using indirect ophthalmoscopy, infrared imaging, and optical coherence tomography to establish the safety profile of the surgery and the device. The biocompatibility of the device was evaluated using histopathological analysis of the tissue surrounding the electrode array, with a focus on the health of the retinal cells required to convey signals to the brain. Appropriate stability of the electrode array was demonstrated, and histological analysis shows that the fibrotic and inflammatory response to the array was mild. Promising evidence of the safety and potential of the Phoenix99 Bionic Eye to restore a sense of vision to the severely visually impaired was obtained.

Risk Factors for Facial Nerve and Other Nonauditory Side Effects Following Cochlear Implantation.

OBJECTIVE: The purpose of this study was to characterize a cohort of patients with nonauditory side-effects (NASx) following cochlear implant (CI) surgery. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: One hundred twenty three multichannel CI recipients with intraoperative facial nerve stimulation (FNS). INTERVENTIONS: Intraoperative electrical auditory brainstem responses (eABR) during CI surgery. MAIN OUTCOME MEASURES: Nonauditory side effects post-CI activation. RESULTS: Intraoperative FNS was identified in 2.26% of patients (123/5441), of whom, 34% (42/123) experienced VII stimulation on CI activation. Pain was experienced by 22% (27/123) and vestibular dysfunction was experienced by 4% (5/123) of cases. All case who experienced pain and/or vestibular NASx also experienced VII stimulation. The majority of cases were managed by CI remapping or observation and habituation.Significant relationships were found between etiology of hearing loss and presence of FNS upon initial activation (p < 0.05). No significance was found between FNS intraoperatively and at initial activation for all assumed mechanisms of hearing loss (p > 0.05) with the exceptions of acquired hearing loss of undetermined etiology and toxic etiology group (p < 0.05).There was no significant impact of implant array design (p > 0.05). CONCLUSIONS: This study has characterized patients with NASx in a large cohort of CI patients. One third of cases identified with FNS intraoperatively, developed NASx post-CI activation. Risk factors for NASx postactivation include high-risk etiologies and intraoperative objective measures (i.e., eABR). This may assist surgeons and audiologists to identify at-risk patients who may need modifications in CI program planning.

Composite gelfoam/fascia graft: a novel technique in tympanoplasty surgery.

BACKGROUND: Traditional tympanoplasty techniques require graft placement and then supporting material (GelFoam) as a two-step process. Both steps potentially disrupt accurate graft placement leading to failure and persistence of the perforation. METHODS: We demonstrate a novel technique for graft preparation and placement using composite gelfoam/fascia in which the gelfoam and fascia are compressed into a common layer and applied to the perforation and drum remnant in a single step. Placement is ergonomically efficient and effective. CONCLUSION: This novel modification of traditional graft preparation and placement is simple and ergonomically efficient.

Validation of a 3D-printed human temporal bone model for otology surgical skill training.

HYPOTHESIS: Three-dimensional (3D) printed temporal bones are comparable to cadaveric temporal bones as a training tool for otologic surgery. BACKGROUND: Cadaveric temporal bone dissection is an integral part of otology surgical training. Unfortunately, availability of cadaveric temporal bones is becoming much more limited and concern regarding chemical and biological risks persist. In this study, we examine the validity of 3D-printed temporal bone model as an alternative training tool for otologic surgery. METHODS: Seventeen otolaryngology trainees participated in the study. They were asked to complete a series of otologic procedures using 3D-printed temporal bones. A semi-structured questionnaire was used to evaluate their dissection experience on the 3D-printed temporal bones. RESULTS: Participants found that the 3D-printed temporal bones were anatomically realistic compared to cadaveric temporal bones. They found that the 3D-printed temporal bones were useful as a surgical training tool in general and also for specific otologic procedures. Overall, participants were enthusiastic about incorporation of 3D-printed temporal bones in temporal bone dissection training courses and would recommend them to other trainees. CONCLUSION: 3D-printed temporal bone model is a viable alternative to human cadaveric temporal bones as a teaching tool for otologic surgery.

Safety and biocompatibility of a bionic eye: Imaging, intraocular pressure, and histology data.

The data presented here are related and supplementary data to the research article "Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep" [1]. In Eggenberger et al., nine sheep of the Suffolk (N=2) and Dorper (N=7) breeds were implanted in the left eye with an electrically inactive, suprachoroidal retinal stimulator (Bionic Eye) for durations of up to 100 days. The surgical safety, implant stability and device biocompatibility were assessed. Intraocular pressure measurements, indirect and infrared ophthalmoscopy and optical coherence tomography were performed at fixed time points to evaluate the clinical effects of the surgery and device implantation. Post-mortem eye tissue collection and histology was performed to measure the effects of the intervention at the cellular level. The data, including a comprehensive collection of fundus, infrared, optical coherence tomography and histology images can be used as a reference for comparison with other research, for example, active retinal stimulators. Furthermore, these data can be used to evaluate the suitability of the sheep model, in particular Dorper sheep, for future research.

Assessing Cochlear Length Using Cone Beam Computed Tomography in Adults With Cochlear Implants.

: Developing a clinically viable technique for measuring cochlear length could enhance future electrode design of cochlear implants and surgical skills to improve clinical outcomes. While computed tomography (CT) has been used, metal artifact and the exposure to higher levels of radiation limits its use. More recently, cone beam CT (CBCT) has been used to assess the integrity of the implant array in situ, exposing implantees to lower levels of radiation while retaining image quality. The current study aims to develop a technique for measuring cochlear length in implanted adults, using CBCT images combined with known dimensions of implant arrays and lengths of cochlear structures from cadaveric human temporal bones. STUDY DESIGN: One hundred CBCT temporal bone images of ears implanted with Cochlear straight or perimodiolar arrays were reviewed by two independent examiners. RESULTS: Outer-wall length, based on the position of the straight array within the cochlea and the reported average length of the organ of Corti, was 27.44 to 35.91 mm (mean = 32.24 mm). Inner-wall length, based on the position of the perimodiolar array and the reported average length of the spiral ganglion, ranged from 17.8 to 22.24 mm (mean = 19.43 mm). CONCLUSION: A novel method for calculating outer- and inner-wall cochlear length using CBCT images has been developed which is feasible in clinical settings.

Pseudogout mimicking an infratemporal fossa tumor.

BACKGROUND: The infratemporal fossa is a well-concealed, complex anatomical space. Neoplasms arising in this area are heterogenous in nature and have an insidious onset and usually present late. METHODS AND RESULTS: We present a case of a 71-year-old woman who presented with worsening facial pain, trismus, and a large mass in her infratemporal fossa with minimal associated temporomandibular joint destruction. She underwent a surgical excision of the mass, which revealed a pseudogout deposit. CONCLUSION: The clinical and radiological features of patients with tophaceous pseudogout frequently mimic those of a benign or malignant neoplasm of the infratemporal fossa, often resulting in more radical surgery.

Endoscopic transnasal decompression for management of basilar invagination in osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a disorder of bone development caused by a genetic dysfunction of collagen synthesis. Basilar invagination (BI) is an uncommon but serious complication of OI. Brainstem decompression in OI is undertaken in certain circumstances. Transoral-transpalatopharyngeal ventral decompression with posterior occipitocervical fusion has become the treatment of choice when required. This technical note outlines a novel endoscopic transnasal approach for ventral decompression. The literature is reviewed and a strategy for the management of BI in patients with OI is outlined.