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.

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.

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.

Drill-Induced Hearing Loss in the Nonoperated Ear

The reversible hearing loss in the nonoperated ear noted by patients after ear surgery remains unexplained. This study proposes that this hearing loss is caused by drill noise conducted to the nonoperated ear by vibrations of the intact skull. This noise exposure results in dysfunction of the outer hair cells, which may produce a temporary hearing loss. Estimations of outer hair cell function in the nonoperated ear were made by recording the change in amplitude of the distortion-product otoacoustic emissions before and during ear surgery. Reversible drill-related outer hair cell dysfunction was seen in 2 of 12 cases. The changes In outer hair cell function and their clinical implications are discussed.