Peter Luke Santa Maria

Histology of the healing tympanic membrane following perforation in rats

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.

Chronic tympanic membrane perforation: a better animal model is needed

Developments in the treatment of chronic tympanic membrane perforation have been hindered by the lack of an ideal animal model. It is not appropriate to test such treatments on acute perforations as the majority of these heal spontaneously. An ideal animal model would be one that most closely resembles the human clinical situation. It should be inexpensive, readily available, and easy to create. There have been a number of attempts to create a chronic tympanic membrane perforation model with limited success. All published attempts at chronic tympanic membrane perforations have been reviewed and the limitations of each model are discussed. A number of areas for research exist for further developing a chronic tympanic membrane perforation model. These areas include a perforation model in the presence of bacteria and eustachian tube dysfunction. Understanding the molecular and genetic mechanisms of chronic otitis media and potential treatments will also be useful.

Cardiac surgery in Australian octogenarians: 1996−2001

Background:  The number of octogenarians receiving cardiac surgery is increasing. Concerns regarding the outcomes and significant expense required to provide this service have not been addressed because no prospective medium term outcomes of Australian octogenarians have been published.

Tympanic membrane wound healing in rats assessed by transcriptome profiling

The aim of this study is to elucidate transcriptional changes that occur in response to tympanic membrane (TM) perforation in rats and to infer key genes and molecular events in the healing process.

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 &mgr;g/ml, n = 18), FGF2 (100 &mgr;g/ml, n = 19), and EGF (250 &mgr;g/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.

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.

A new theory on the pathogenesis of acquired cholesteatoma: Mucosal traction

Although the migration of its squamous outer surface of the tympanic membrane has been well characterized, there is a paucity of data available concerning the migratory behavior of its medial mucosal surface. Existing theories of primary acquired cholesteatoma pathogenesis do not adequately explain the observed characteristics of the disease. We propose a new hypothesis, based upon a conjecture that mucosal membrane interactions are the driving force in cholesteatoma.

When is the best timing for the second implant in pediatric bilateral cochlear implantation

BACKGROUND The benefits of bilateral cochlear implantation in the pediatric population include better sound localization, benefits with speech in noise, and improved language development. In the pediatric patient who meets the criteria for bilateral cochlear implantation, should the surgeries be performed simultaneously or sequentially? If sequentially, what is the best timing? The importance of early implantation in this group has been recognized; however, some concerns have affected the timing of the second implant. Concerns that bilateral implantation may risk bilateral vestibular hypofunction, the loss of an intact cochlear for future therapies, or financial and reimbursement issues have lead some clinics to wait for the second side. Families may choose to wait for a variety of nonmedical reasons. This article aims to address these issues, as well as to review the benefits of early implantation in the second side.

Temporal-Bone Measurements of the Maximum Equivalent Pressure Output and Maximum Stable Gain of a Light-Driven Hearing System That Mechanically Stimulates the Umbo.

Hypothesis: That maximum equivalent pressure output (MEPO) and maximum stable gain (MSG) measurements demonstrate high output and high gain margins in a light-driven hearing system (Earlens). Background: The nonsurgical Earlens consists of a light-activated balanced-armature transducer placed on the tympanic membrane (Lens) to drive the middle ear through direct umbo contact. The Lens is driven and powered by encoded pulses of light. In comparison to conventional hearing aids, the Earlens is designed to provide higher levels of output over a broader frequency range, with a significantly higher MSG. MEPO provides an important fitting guideline. Methods: Four fresh human cadaveric temporal bones were used to measure MEPO directly. To calculate MEPO and MSG, we measured the pressure close to the eardrum and the stapes velocity, for sound drive and light drive using the Earlens. Results: The baseline sound-driven measurements are consistent with previous reports. The average MEPO (n = 4) varies from 116 to 128 dB SPL in the 0.7 to 10 kHz range, with the peak occurring at 7.6 kHz. From 0.1 to 0.7 kHz, it varies from 83 to 121 dB SPL. For the average MSG, a broad minimum of about 10 dB occurs in the 1 to 4 kHz range, above which it rises as high as 42 dB at 7.6 kHz. From 0.2 to 1 kHz, the MSG decreases linearly from approximately 40 dB to 10 dB. Conclusion: With high output and high gain margins, the Earlens may offer broader-spectrum amplification for treatment of mild-to-severe hearing impairment.

Mouse model of experimental Eustachian tube occlusion: a surgical technique

Abstract Conclusion: The present study demonstrates a mouse model of chronic Eustachian tube (ET) dysfunction using a surgical technique that is reproducible and effective with low mortality and morbidity. Objective: To create a reproducible and effective mouse model of ET obstruction with a low operative morbidity. Methods: Forty healthy, male CBA/CaJ mice underwent the procedure. ET obstruction was performed on one side under general anesthesia; A small piece of dental material (Gutta Percha Points, Meta Biomed, Chungbuk, Korea) was placed via the tympanic orifice of the ET to occlude the entire ET. The contralateral ears of animals served as a control. One month after the operation, all ears were inspected under an operating microscope for signs of ET dysfunction. Primary outcome measures were the signs of ET dysfunction inspected through tympanic membrane (TM) 4 weeks after the operation and confirmation of ET occlusion by post-mortem dissection. Results: Forty (100%) of the treated mice ears developed ET dysfunction, as confirmed by the middle ear appearance on otoscopy and dissection post-mortem and 0% of the control ears at 4 weeks. The most common otoscopic signs were thickened TMs and middle ear effusions. No mortality or morbidity occurred either from anesthesia or surgery.