Optical Coherence Tomography of the Tympanic Membrane and Middle Ear: A Review.

Objective To evaluate the recent developments in optical coherence tomography (OCT) for tympanic membrane (TM) and middle ear (ME) imaging and to identify what further development is required for the technology to be integrated into common clinical use. Data Sources PubMed, Embase, Google Scholar, Scopus, and Web of Science. Review Methods A comprehensive literature search was performed for English language articles published from January 1966 to January 2018 with the keywords "tympanic membrane or middle ear,""optical coherence tomography," and "imaging." Conclusion Conventional imaging techniques cannot adequately resolve the microscale features of TM and ME, sometimes necessitating diagnostic exploratory surgery in challenging otologic pathology. As a high-resolution noninvasive imaging technique, OCT offers promise as a diagnostic aid for otologic conditions, such as otitis media, cholesteatoma, and conductive hearing loss. Using OCT vibrometry to image the nanoscale vibrations of the TM and ME as they conduct acoustic waves may detect the location of ossicular chain dysfunction and differentiate between stapes fixation and incus-stapes discontinuity. The capacity of OCT to image depth and thickness at high resolution allows 3-dimensional volumetric reconstruction of the ME and has potential use for reconstructive tympanoplasty planning and the follow-up of ossicular prostheses. Implications for Practice To achieve common clinical use beyond these initial discoveries, future in vivo imaging devices must feature low-cost probe or endoscopic designs and faster imaging speeds and demonstrate superior diagnostic utility to computed tomography and magnetic resonance imaging. While such technology has been available for OCT, its translation requires focused development through a close collaboration between engineers and clinicians.

Type I Tympanoplasty Meta-Analysis: A Single Variable Analysis.

OBJECTIVE: To determine which independent variables influence the efficacy of type I tympanoplasty in adult and pediatric populations. DATA SOURCES: A search of the PubMed database and Cochrane Database of Systematic Reviews using the key words "tympanoplasty OR myringoplasty" from January 1966 to July 2014 was performed. STUDY SELECTION: Studies reporting outcomes of myringoplasty or Type I tympanoplasty in primary non-cholesteatomatous chronic tympanic membrane (TM) perforation were included. DATA EXTRACTION: Of 4,698 abstracts reviewed, 214 studies involving 26,097 patients met our inclusion criteria and contributed to meta-analysis. DATA SYNTHESIS: The primary outcome of success was defined as closure rate at 12 months. The independent variables analyzed were age, follow-up period, approach, graft material, perforation cause, size, location, ear dryness, and surgical technique. Only those studies providing data on a given parameter of interest could be included when comparing each variable. CONCLUSION: The weighted average success rate of tympanic closure was 86.6%. Based on this meta-analysis, pediatric surgery has a 5.8% higher failure rate than adults and there is no correlation between follow-up period and success. Other variables associated with improved closure rates include perforation with a size less than 50% of total area (improved by 6.1%) and the use of cartilage as a graft (improved by 2.8% compared with fascia), while ears that were operated on while still discharging, those in different locations of the pars tensa, or using different surgical approaches or techniques did not have significantly different outcomes.

Hearing preservation surgery for cochlear implantation: a meta-analysis.

OBJECTIVE: To examine the results of hearing preservation in cochlear implantation surgery to identify surgical technical factors, electrode array design factors, and steroid usage, which predicts greater low-frequency hearing preservation. DATA SOURCES: A thorough search of Medline and Pubmed of English studies from January 1, 1995, to January 1, 2013, was performed using the key words "electric and acoustic hearing" or "hybrid cochlear implant" or "EAS cochlear implant" or "partial deafness cochlear implant" or "bimodal hearing cochlear implant" or "hearing preservation cochlear implant." STUDY SELECTION: The meta-analysis was conducted according to the PRISMA statement. Only articles in English were included. Studies were included if hearing preservation was the primary end point. A final number of 24 studies met the inclusion criteria. DATA EXTRACTION: Patient populations were analyzed as intention to treat. Data were extracted from raw audiograms where possible. Data were excluded if not all explanatory variables were present or if variable values were ambiguous. DATA SYNTHESIS: The weighted least-squares regression method was used to determine the predictive power of each explanatory variable across all studies. CONCLUSION: In this meta-analysis, the following are associated with better hearing preservation: cochleostomy over the round window approach, posterior tympanotomy over the suprameatal approach, a slow electrode array insertion technique over insertion of less than 30 seconds, a soft tissue cochleostomy seal over a fibrin glue only seal and the use of postoperative systemic steroids. Longer electrode arrays, topical steroid use, and lubricant use for electrode array insertion did not give an advantage.

Scaffolds for tympanic membrane regeneration in rats.

Tympanic membrane (TM) perforations lead to significant hearing loss and result in possible infection of the middle ear. Myringoplasty is commonly performed to repair chronic perforations. Although various grafts and materials have been used to promote TM regeneration, all have associated limitations. The aim of this study was to evaluate the efficacy and feasibility of two graft materials, silk fibroin scaffold (SFS) and porcine-derived acellular collagen type I/III scaffold (ACS), compared with two commonly used graft materials (paper patch and Gelfoam) for the promotion of TM regeneration. These scaffolds were implanted using on-lay myringoplasty in an acute TM perforation rat model. Surface morphology of the scaffolds was observed with scanning electron microscopy. The morphology of the TM was assessed at various time points postimplantation using otoscopy, light and electron microscopy, and functional outcomes by auditory brainstem responses. We found that SFS and ACS significantly accelerated the TM perforation closure, obtained optimal TM thickness, and resulted in better trilaminar morphology with well-organized collagen fibers and early restoration of hearing. However, paper patch and Gelfoam lost their scaffold function in the early stages and showed an inflammatory response, which may have contributed to delayed healing. This study indicates that compared with paper patch and Gelfoam, SFS and ACS are more effective in promoting an early TM regeneration and an improved hearing, suggesting that these scaffolds may be potential substitutes for clinical use.

Mobile and landline telephone performance outcomes among telephone-using cochlear implant recipients.

OBJECTIVE: To objectively study mobile and standard landline telephone speech perception performance using cochlear implant recipients. STUDY DESIGN: Nonrandomized trial. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Twenty-five subjects enrolled in this study from a pool of 50 cochlear implant recipients who had participated in an earlier questionnaire study from which demographic data were gathered. Preoperative speech perception scores were collated from preoperative audiological data. Postoperative speech perception scores were calculated with subjects listening to the Australian Version of the Bamford-Kowal-Bench Sentence Test read aloud in a soundproof booth via live voice, played back on a speaker, on a standard landline and mobile phone. Telephone speech perception scores were analyzed and banded into 3 performance categories: very good (90%-100%), good (80%-89%), and fair (<80%). RESULTS: The mean speech perception scores were 88.6% (SD, 14.3%) for postoperative recorded speech and 92.3% (SD, 10.7%) for live voice listening, which were significantly better than the mean score of 37.2% (SD, 29.1%) listening to recorded voice preoperatively. The mean speech perception score was 84.3% (SD, 20.7%) using a mobile telephone and 57% (SD, 29.4%) using the standard landline. Further analysis showed better performance with mobile phones over standard landlines. Seventy-six percent of subjects attained at least good telephone speech performance (score >80%). Older patients had poorer telephone speech perception than younger patients did. CONCLUSIONS: Many cochlear implant recipients achieve good objective telephone speech perception performance, indicating that they should be effective telephone users, especially when using mobile telephones and among younger implant recipients.

To pack or not to pack? A contemporary review of middle ear packing agents.

Middle ear packing agents are used in otologic surgery to provide support to the middle ear structures, maintain aeration of the middle ear, and promote hemostasis. However, there is currently a lack of standardization regarding the use of different types of packing agents. The choice of materials and how they are used remain controversial. In fact, some have recently advocated for no packing. In view of this, this review focuses on the types of materials available, a brief historical account of each material, characteristics of an ideal packing agent, and a discussion on the techniques of insertion to optimize surgical outcomes.

Histology of the healing tympanic membrane following perforation in rats.

OBJECTIVES/HYPOTHESIS: The aim of this study was to provide a detailed cytological account on the healing tympanic membrane (TM) over 14 days and to complement existing research into TM wound healing. STUDY DESIGN: The study is a prospective cohort study of 19 male Sprague-Dawley (Rattus norvegicus) rats. METHODS: Rat TMs were perforated using a sterile needle and sacrificed at time points during the 14 days following perforation. RESULTS: The healing of the TM resembles cutaneous wound healing except that the TM is unique in the lack of a supportive matrix beneath the regenerating epithelia. This prevents the influx of reparative cells and nutrients and the in growth of the usual fibroblastic reaction. CONCLUSIONS: TM wound healing contrasts with cutaneous wound healing in that keratinocytes are the first cells to close the wound and not the last. A keratin scaffold may not be important in the healing process. The malleus plays a crucial role in the healing of the TM and is the site of significant mitotic activity during the healing process. Migration across layers of the TM appears to account for the closure of the perforation.

Preliminary results of the application of a silk fibroin scaffold to otology.

The surgical treatment to repair chronic tympanic membrane perforations is myringoplasty. Although multiple autologous grafts, allografts, and synthetic graft materials have been used over the years, no single graft material is superior for repairing all perforation types. Recently, the remarkable properties of silk fibroin protein have been studied, with biomedical and tissue engineering applications in mind, across a number of medical and surgical disciplines. The present study examines the use of silk fibroin for its potential suitability as an alternative graft in myringoplasty surgery by investigating the growth and proliferation of human tympanic membrane keratinocytes on a silk fibroin scaffold in vitro. Light microscopy, immunofluorescent staining, and confocal imaging all reveal promising preliminary results. The biocompatibility, transparency, stability, high tensile strength, and biodegradability of fibroin make this biomaterial an attractive option to study for this utility.

Grafts in myringoplasty: utilizing a silk fibroin scaffold as a novel device.

Chronic perforations of the eardrum or tympanic membrane represent a significant source of morbidity worldwide. Myringoplasty is the operative repair of a perforated tympanic membrane and is a procedure commonly performed by otolaryngologists. Its purpose is to close the tympanic membrane, improve hearing and limit patient susceptibility to middle ear infections. The success rates of the different surgical techniques used to perform a myringoplasty, and the optimal graft materials to achieve complete closure and restore hearing, vary significantly in the literature. A number of autologous tissues, homografts and synthetic materials are described as graft options. With the advent and development of tissue engineering in the last decade, a number of biomaterials have been studied and attempts have been made to mimic biological functions with these materials. Fibroin, a core structural protein in silk from silkworms, has been widely studied with biomedical applications in mind. Several cell types, including keratinocytes, have grown on silk biomaterials, and scaffolds manufactured from silk have successfully been used in wound healing and for tissue engineering purposes. This review focuses on the current available grafts for myringoplasty and their limitations, and examines the biomechanical properties of silk, assessing the potential benefits of a silk fibroin scaffold as a novel device for use as a graft in myringoplasty surgery.