Epidemiology of Chronic Suppurative Otitis Media in the United States.

OBJECTIVE: This study aimed to evaluate the prevalence, incidence, and associated demographic factors of chronic suppurative otitis media (CSOM), utilizing a nationwide healthcare claims database. METHODS: This retrospective study utilized outpatient administrative claims data from the IBM MarketScan Research Database from 2007 to 2021. The database (11 246 909 584 claims with 148 147 615 unique patients) includes health data from the private-sector, Medicare/Medicaid, managed care providers, and EMR providers. Included patients had a diagnosis of CSOM based on ICD-9-CM and ICD-10-CM codes. Prevalence and health utilization were estimated by age, gender, and geographic region. RESULTS: In the United States, the estimated CSOM prevalence and incidence was 0.46% and 0.03%, respectively. Among CSOM patients (n = 679 906), mean age (SD) was 8.1 (15.4) years, and 52.8% were male. Most patients (81.1%) were aged 0 to 10 years. CSOM prevalence was lower in females (OR = 0.64, 95% CI 0.64-0.65, P < .001), less common in older age (OR = 0.94, 95% CI 0.94-0.94, P < .001), and highest in the South region (OR = 2.08, 95% CI 2.06-2.09, P < .001). CONCLUSION: Our results show CSOM prevalence (0.46%) is similar to other developed countries. CSOM prevalence was highest in those aged 0 to 10 years, in males and in the South region. Of note, prevalence and cost are likely significantly underestimated given limitations in accurate ICD-CM coding and the exclusion of uninsured patients. Further epidemiological studies are warranted to characterize the impact of CSOM on the US healthcare system.

PANEL 3: Otitis media animal models, cell culture, tissue regeneration & pathophysiology.

OBJECTIVE: To review and summarize recently published key articles on the topics of animal models, cell culture studies, tissue biomedical engineering and regeneration, and new models in relation to otitis media (OM). DATA SOURCE: Electronic databases: PubMed, National Library of Medicine, Ovid Medline. REVIEW METHODS: Key topics were assigned to the panel participants for identification and detailed evaluation. The PubMed reviews were focused on the period from June 2019 to June 2023, in any of the objective subject(s) or keywords listed above, noting the relevant references relating to these advances with a global overview and noting areas of recommendation(s). The final manuscript was prepared with input from all panel members. CONCLUSIONS: In conclusion, ex vivo and in vivo OM research models have seen great advancements in the past 4 years. From the usage of novel genetic and molecular tools to the refinement of in vivo inducible and spontaneous mouse models, to the introduction of a wide array of reliable middle ear epithelium (MEE) cell culture systems, the next five years are likely to experience exponential growth in OM pathophysiology discoveries. Moreover, advances in these systems will predictably facilitate rapid means for novel molecular therapeutic studies.

Minimally invasive trans-tympanic eustachian tube occlusion animal model.

OBJECTIVE: Eustachian tube dysfunction is believed to be involved in the pathogenesis of many middle ear diseases including chronic suppurative otitis media. We aimed to describe a simple and reliable animal model of Eustachian Tube obstruction to further research into middle ear disorders. STUDY DESIGN: Prospective cohort study in animals. SETTING: University laboratory. SUBJECTS AND METHODS: 30 mice C57Bl/6J (n = 15) and CBA/CaJ (n = 15) aged 6-8 weeks received transtympanic Eustachian tube occlusion on left ear trough an acute tympanic membrane perforation using thermoplastic latex used in dental procedures (gutta percha). Control mice (n = 6) received tympanic membrane perforation only. At two and four weeks, the mice were observed for signs of Eustachian tube dysfunction and compared to control ears. ET dysfunction was defined as presence of effusion in the middle ear. RESULTS: 100% (n = 30) of the treated ears had otoscopic signs of Eustachian tube dysfunction at two weeks and the endpoint time of four weeks, compared to 0% in control mice (0/6). Temporary head tilt lasting up to 2 days were observed in 3 mice (10%). No other potential adverse events were recorded. No bacterial growth was determined in the middle ear fluid. CONCLUSION: We describe a technically easy and reliable method for Eustachian tube occlusion in mice with an excellent success rate and minimal morbidity.

Middle Cranial Fossa Approach to Repair Tegmen Dehiscence Using Self-setting Calcium Phosphate Cement: A Retrospective Case Review.

OBJECTIVES: To review the outcomes of repairing tegmen dehiscence using the middle cranial fossa approach with a self-setting bone cement. STUDY DESIGN: Retrospective case series. SETTING: Two academic tertiary hospitals. PATIENTS: All patients presenting for surgical repair of tegmen dehiscence and with postoperative follow-up for at least 6 months between October 2015 and July 2019. INTERVENTION: Surgical repair using a middle cranial fossa approach using a layered reconstruction with temporalis fascia and self-setting calcium phosphate bone cement. MAIN OUTCOME MEASURES: Perioperative complications, recurrence of presenting symptoms/disease, hearing, and facial nerve grade. RESULTS: The cohort consisted of 22 patients with 23 tegmen dehiscence repairs (1 sequential bilateral repair). There were 16 males and 6 females with an average age at operation of 52.6 years. Repairs were left sided in 9, right sided in 12 patients, and bilateral in 1 patient. No patients had recurrence of presenting symptoms or disease at most recent follow-up. Preoperative hearing was maintained in all patients. Two patients (9% of repairs) experienced delayed partial temporary facial nerve weakness House-Brackman grade 2 and 4 which had recovered by 8 weeks postoperative. CONCLUSION: We demonstrate a technique for repairing tegmen dehiscence of the middle cranial fossa floor that has excellent postoperative outcomes. We highlight potential technical challenges in this approach as well as the need for counseling for potential partial transient facial nerve dysfunction.

A design-thinking approach to therapeutic translation: tympanic regeneration.

PURPOSE OF REVIEW: Clinician researchers face the pressures of meeting academic benchmarks combined with advancing new therapies to patients. The vast majority of drug discoveries fail in translation. A new method of meeting the challenges of preclinical therapeutic translation is presented using the example of tympanic regeneration. RECENT FINDINGS: The key to a design-thinking approach to therapeutic translation is to 'begin with the end in mind' by widening the scope of the problem, with multiple points of view, to not only understand the disease but the context for the patient and the health system in which it occurs. Idea for therapeutics should be tested in relevant models early and once proof of efficacy is established, translational milestones that represent the greatest risk, such as safety and toxicity should be addressed first. It is important to seek the feedback of industry early to understand what milestones should be best addressed next with limited academic resources. Whenever proceeding, guidelines for maintaining scientific reproducibility should be followed to minimize risk of failure during transfer into industry. SUMMARY: A Design-thinking approach addresses the potential failures in drug discovery and preclinical translation.

New Medical Device and Therapeutic Approvals in Otolaryngology: State of the Art Review of 2019.

OBJECTIVE: To review new devices and drugs relevant to otolaryngology-head and neck surgery that were approved by the US Food and Drug Administration (FDA) in 2019. DATA SOURCES: Approval notifications for 2019 were extracted from the ENT (ear, nose, and throat) and general and plastic surgery sections of the FDA's medical devices and therapeutics listings. REVIEW METHODS: New therapeutics and medical devices identified from the query were analyzed by members of the American Academy of Otolaryngology-Head and Neck Surgery's Medical Devices and Drugs Committee. Technologies were assessed by 2 independent reviewers to ascertain relevance to otolaryngology, prioritized, and classified to subspecialty field with critical review based on extant scientific literature. CONCLUSIONS: Query of the FDA drug and device database returned 105 ENT devices (50 cleared, 55 with premarket approval, and 0 de novo), 543 general and plastic surgery devices (372 cleared, 170 with premarket approval, and 1 de novo), and 46 new otolaryngology-relevant drug approvals that occurred in 2019. Advances spanned all subspecialty areas with otology predominating, primarily due to hearing-related technologies. While scientific evidence was available for all new devices, there was significant heterogeneity in rigor of supporting scientific data. IMPLICATIONS FOR PRACTICE: Technological and pharmaceutical innovation is an important catalyst for advances in the surgical specialties. Familiarity with new devices and therapeutics in otolaryngology-head and neck surgery ensures that clinicians keep abreast of developments with potential to improve prevailing standards of care.

A Review of the Contribution of Mast Cells in Wound Healing: Involved Molecular and Cellular Mechanisms.

Mast cells (MCs), apart from their classic role in allergy, contribute to a number of biologic processes including wound healing. In particular, two aspects of their histologic distribution within the skin have attracted the attention of researchers to study their wound healing role; they represent up to 8% of the total number of cells within the dermis and their cutaneous versions are localized adjacent to the epidermis and the subdermal vasculature and nerves. At the onset of a cutaneous injury, the accumulation of MCs and release of proinflammatory and immunomodulatory mediators have been well documented. The role of MC-derived mediators has been investigated through the stages of wound healing including inflammation, proliferation, and remodeling. They contribute to hemostasis and clot formation by enhancing the expression of factor XIIIa in dermal dendrocytes through release of TNF-α, and contribute to clot stabilization. Keratinocytes, by secreting stem cell factor (SCF), recruit MCs to the site. MCs in return release inflammatory mediators, including predominantly histamine, VEGF, interleukin (IL)-6, and IL-8, that contribute to increase of endothelial permeability and vasodilation, and facilitate migration of inflammatory cells, mainly monocytes and neutrophils to the site of injury. MCs are capable of activating the fibroblasts and keratinocytes, the predominant cells involved in wound healing. MCs stimulate fibroblast proliferation during the proliferative phase via IL-4, vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) to produce a new extracellular matrix (ECM). MC-derived mediators including fibroblast growth factor-2, VEGF, platelet-derived growth factor (PDGF), TGF-ß, nerve growth factor (NGF), IL-4, and IL-8 contribute to neoangiogenesis, fibrinogenesis, or reepithelialization during the repair process. MC activation inhibition and targeting the MC-derived mediators are potential therapeutic strategies to improve wound healing through reduced inflammatory responses and scar formation.

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.

Age-Related Hearing Loss: Innovations in Hearing Augmentation.

Age-related hearing loss is a multifactorial condition that affects more than one-third of the aging population. Left untreated it can increase the risk of cognitive decline, dementia, social isolation, depression, and falls. Hearing augmentation devices exhibit improved digital sound processing and Smartphone connectivity. Stigma remains one of the prominent barriers and todays devices offer in the canal models, miniature sizes, and camouflage with the hair or skin color. Although rigorous scientific efforts are made in the research field of inner ear regeneration and some clinical early phase studies do exist, to date, the clinical availability is still some time away.

Epithelial separation theory for post-tonsillectomy secondary hemorrhage: evidence in a mouse model and potential heparin-binding epidermal growth factor-like growth factor therapy.

OBJECTIVE: To provide histological evidence to investigate a theory for post-tonsillectomy secondary hemorrhage (PTH) in a mouse model and to evaluate the potential for heparin-binding epidermal growth factor-like growth factor (HB-EGF) treatment on wound healing in this model. METHODS: A prospective randomized single-blinded cohort study. A uniform tongue wound was created in 84 mice (day 0). Mice were randomized to HB-EGF (treatment, n = 42) or saline (control, n = 42). In treatment mice, HB-EGF 5 µg/ml was administered intramuscularly into the wound daily (days 0-14). In control mice, normal saline was administered daily. Three mice from each group were sacrificed daily through day 14 and the wounds evaluated histologically by blinded reviewers. RESULTS: Key stages of wound healing, including keratinocyte proliferation and migration, wound contraction, epithelial separation, and neoangiogenesis, are defined with implications for post-tonsillectomy wound healing. Epithelial separation (59 vs. 100%, p = 0.003) and wound reopening (8 vs. 48%, p < 0.001) were reduced with HB-EGF. Epithelial thickness (220 vs. 30 µm, p = 0.04) was greater with HB-EGF. Wound closure (days 4-5 vs. day 6, p = 0.01) occurred earlier with HB-EGF. CONCLUSIONS: In healing of oral keratinocytes on muscle epithelial separation secondary to muscle, contraction occurs concurrently with neoangiogenesis in the base of the wound, increasing the risk of hemorrhage. This potentially explains why post-tonsillectomy secondary hemorrhage occurs and its timing. HB-EGF-treated wounds showed greater epithelial thickness, less frequent epithelial separation and wound reopening, and earlier wound closure prior to neovascularization, suggesting that HB-EGF may be a potential preventative therapy for PTH. LEVEL OF EVIDENCE: NA-animal studies or basic research.

A novel thermal compression device for perioperative warming: a randomized trial for feasibility and efficacy.

BACKGROUND: Inadvertent perioperative hypothermia (IPH) leads to surgical complications and increases length of stay. IPH rates are high with the current standard of care, forced air warming (FAW). Our hypothesis is that a prototype thermal compression device that heats the popliteal fossa and soles of the feet, with lower leg compression, increases perioperative temperatures and reduces IPH compared to the current standard of care. METHODS: Thirty six female breast surgery patients, at a tertiary academic hospital, were randomized to the device or intraoperative FAW (stage I) with a further 18 patients randomized to the device with a single heating area only (stage II, popliteal fossa or sole of the feet). Stage I: 37 patients recruited (final 36). Stage II: 18 patients recruited (final 18). INCLUSION CRITERIA: general anesthesia with esophageal monitoring for over 30 min, legs available and able to fit the device and no contraindications to leg heating or compression. The intervention was: Stage I: Investigational prototype thermal compression device (full device group) or intraoperative FAW. Stage II: Device with only a single heating location. Primary outcomes were perioperative temperatures and incidence of IPH. Secondary outcomes were local skin temperature, general and thermal comfort scores and presence of perioperative complications, including blood loss. RESULTS: Mean temperatures in the full device group were significantly higher than the FAW group in the pre-operative (36.7 vs 36.4 °C, p < 0.001), early intraoperative (36.3 vs 35.9 °C, p < 0.001), intraoperative (36.6 vs 36.2 °C, p < 0.001) and postoperative periods (36.8 vs 36.5 °C, p < 0.001). The incidence of IPH in the device group was also significantly lower (16.7% vs 72.0%, p = 0.001). Thermal comfort scores were significantly higher in the full device group and hypothermia associated wound complications were higher in the FAW group. CONCLUSIONS: The thermal compression device is feasible and has efficacy over the FAW. Further studies are recommended to investigate clinically significant outcomes. TRIAL REGISTRATION: clinicaltrials.gov ( NCT02155400 ).

Functional Outcomes of Heparin-Binding Epidermal Growth Factor-Like Growth Factor for Regeneration of Chronic Tympanic Membrane Perforations in Mice.

We aim to demonstrate that regeneration of chronic tympanic perforations with heparin-binding epidermal growth factor-like growth factor (HB-EGF) delivered by an injectable hydrogel restored hearing to levels similar to that of nonperforated tympanic membranes. Chronic tympanic membrane perforation is currently managed as an outpatient surgery with tympanoplasty. Due to the costs of this procedure in the developed world and a lack of accessibility and resources in developing countries, there is a great need for a new treatment that does not require surgery. In this study, we show in a mouse model through measurement of auditory brainstem response and distortion product otoacoustic emissions that tympanic perforations lead to hearing loss and this can be predominantly recovered with HB-EGF treatment (5 µg/mL). Our animal model suggests a return to function between 2 and 6 months after treatment. Auditory brainstem response thresholds had returned to the control levels at 2 months, but the distortion product otoacoustic emissions returned between 2 and 6 months. We also show how the vibration characteristics of the regenerated tympanic membrane, as measured by laser Doppler vibrometry, can be similar to that of an unperforated tympanic membrane. Using the best available methods for preclinical evaluation in animal models, it is likely that HB-EGF-like growth factor treatment leads to regeneration of chronic tympanic membrane perforations and restoration of the tympanic membrane to normal function, suggesting a potential route for nonsurgical treatment.

Single Administration of a Sustained-Release Formulation of KB-R7785 Inhibits Tympanic Membrane Regeneration in an Animal Model.

OBJECTIVE: A pressure equalization tube placed within the tympanic membrane is the only clinically available method for inhibiting tympanic membrane regeneration. Problems associated with this include associated otorrhea, biofilm formation, medial migration of the tube, tube retention, induction of granulation tissue, and a small but significant rate of cholesteatoma. We aimed to demonstrate that a single administration of a sustained-release polymer formulation of KB-R7785 maintains tympanic membrane perforation for at least 6 months. MATERIALS AND METHODS: Sustained-release KB-R7785 was delivered within a novel polymer hydrogel to 20 mice with bilateral acute tympanic membrane perforations (a total of 40 perforations). The perforations were monitored at 3-month intervals until 9 months. RESULTS: At 3 months, 90% of perforations were open (n=36/40). At 6 months, 75% of perforations were open (total n=30/40). At 9 months, 22.5% of perforations were open (total n=6/40). The majority of tympanic membrane perforations (75%) were open (not healed) beyond 6 months and close (fully healed) prior to 9 months (77.5%). Once healed, tympanic membranes resembled their normal histological appearance. CONCLUSION: This study demonstrates that a single administration of a sustained-release polymer formulation of KB-R7785 inhibits tympanic membrane regeneration for 6-9 months.

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.

No systemic exposure of transtympanic heparin-binding epidermal growth factor like growth factor.

CONTEXT: Heparin-binding epidermal growth factor like growth factor (HB-EGF) is an emerging therapeutic for the regeneration of the tympanic membrane (TM). OBJECTIVE: Our aim was to determine whether the doses of HB-EGF delivered in a sustained release hydrogel into a middle ear mouse model, would be measurable in the systemic circulation. We also aimed to observe, in the scenario that the intended dose was absorbed directly into the circulation, whether these levels could be measured above the background levels of HB-EGF in the circulation. METHODS: A total of 12 mice had transtympanic injections of 5 µg/ml of HB-EGF contained within a previously described novel hydrogel vehicle, while another 12 mice had intravenous delivery of 10 µg/kg of HB-EGF. Intravenous blood samples were collected at 0-, 3-, 24-, 168-, 288- and 720-h post-injection. A double-antibody sandwich one-step process enzyme-linked immunosorbent assay (ELISA) was used to determine the level of HB-EGF in the serum. RESULTS: No mice in the transtympanic administration group and no mice in the intravenous administration group were found to have blood level measured above that in the controls. DISCUSSION: The inability of the positive control to measure levels above background, suggest the total dose used in our studies, even if 100% absorbed into the system circulation is insignificant. CONCLUSIONS: HB-EGF at the doses and delivery method proposed for treatment of chronic TM perforation in a mouse model are likely to have no measurable systemic effect.

Heparin Binding Epidermal Growth Factor-Like Growth Factor Heals Chronic Tympanic Membrane Perforations With Advantage Over Fibroblast Growth Factor 2 and Epidermal Growth Factor in an Animal Model.

HYPOTHESIS: That heparin binding epidermal growth factor-like growth factor (HB-EGF) heals chronic tympanic membrane (TM) perforations at higher rates than fibroblast growth factor 2 (FGF2) and epidermal growth factor (EGF) in an animal model. BACKGROUND: A nonsurgical treatment for chronic TM perforation would benefit those unable to access surgery or those unable to have surgery, as well as reducing the cost of tympanoplasty. Growth factor (GF) treatments have been reported in the literature with variable success with the lack of a suitable animal providing a major obstacle. METHODS: The GFs were tested in a validated mouse model of chronic TM perforation. A bioabsorbable hydrogel polymer was used to deliver the GF at a steady concentration as it dissolved over 4 weeks. A control (polymer only, n = 18) was compared to polymer loaded with HB-EGF (5 µg/ml, n = 18), FGF2 (100 µg/ml, n = 19), and EGF (250 µg/ml, n = 19). Perforations were inspected at 4 weeks. RESULTS: The healing rates, as defined as 100% perforation closure, were control (5/18, 27.8%), HB-EGF (15/18, 83.3%), FGF2 (6/19, 31.6%), and EGF (3/19, 15.8%). There were no differences between FGF2 (p = 0.80) and EGF (p = 0.31) with control healing rates. HB-EGF (p = 0.000001) showed a significant difference for healing. The HB-EGF healed TMs showed layers similar to a normal TM, whereas the other groups showed a lack of epithelial migration. CONCLUSION: This study confirms the advantage of HB-EGF over two other commonly used growth factors and is a promising nonsurgical treatment of chronic TM perforations.

Heparin binding-epidermal growth factor-like growth factor for the regeneration of chronic tympanic membrane perforations in mice.

We aim to explore the role of epidermal growth factor (EGF) ligand shedding in tympanic membrane wound healing and to investigate the translation of its modulation in tissue engineering of chronic tympanic membrane perforations. Chronic suppurative otitis media (CSOM) is an infected chronic tympanic membrane perforation. Up to 200 million suffer from its associated hearing loss and it is the most common cause of pediatric hearing loss in developing countries. There is a need for nonsurgical treatment due to a worldwide lack of resources. In this study, we show that EGF ligand shedding is essential for tympanic membrane healing as it's inhibition, with KB-R7785, leads to chronic perforation in 87.9% (n=58) compared with 0% (n=20) of controls. We then show that heparin binding-EGF-like growth factor (5 µg/mL), which acts to shed EGF ligands, can regenerate chronic perforations in mouse models with 92% (22 of 24) compared with 38% (10 of 26), also with eustachian tube occlusion with 94% (18 of 19) compared with 9% (2 of 23) and with CSOM 100% (16 of 16) compared with 41% (7 of 17). We also show the nonototoxicity of this treatment and its hydrogel delivery vehicle. This provides preliminary data for a clinical trial where it could be delivered by nonspecialist trained healthcare workers and fulfill the clinical need for a nonsurgical treatment for chronic tympanic membrane perforation and CSOM.

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.