Development of a calcium alginate tympanostomy tube

An Overview of the Tympanostomy Tube

Otitis media is a disorder of the middle ear, which can occur at any age but is more common among infants and children. The patient usually presents with earaches, impaired hearing, and fever. If antibiotics and decongestants do not suit the patient, a myringotomy can be performed to achieve middle ear aeration. In myringotomy, a slit is created in the tympanic membrane, and fluid is removed with suction. In cases where myringotomy, aspiration, and medical care don't help and the fluid recurs, a tympanostomy tube is inserted to create continuous aeration of the middle ear. A tympanostomy tube is a small tube inserted in the tympanic membrane which helps in the prevention of fluid accumulation in the middle ear. These tubes are temporary and often fall off after the ear heals. Other names for tympanostomy tubes are grommet, myringotomy tube, or pressure equalizing tube. Initially, tympanostomy tubes were made of metal but now fluoroplastic or silicone elastomers are used to make them. The two basic designs of a tympanostomy tube are short-term tube and long-term tube. The choice of a tympanostomy tube depends on factors like age, the period needed for ventilation, socioeconomic status, and the extent of the retracted eardrum. The incidence of occlusion, infection, functional duration, and persistent perforation following extrusion varies between the designs and materials. Every year, many children are affected by recurrent otitis media, which can negatively influence their quality of life and their ability to hear and communicate. With so many children requiring tympanostomy tubes, choosing the appropriate tube is vital to provide optimal treatment and limit complications.

"On-command" dissolvable tympanostomy tube in the chinchilla model: A proof of concept

OBJECTIVES

To prove the concept that a dissolvable "on-command" tympanostomy tube placed into the tympanic membrane of a chinchilla can dissolve when a benign solution is applied and result in a well healed tympanic membrane without histologic evidence of injury.

STUDY DESIGN

Prospective Randomized Single-Subject Controlled Trial.

METHODS

Prototype tympanostomy tubes were fabricated from poly(butyl methacrylate-co-(2-dimethylaminoethyl) methacrylate-co- methyl methacrylate) (PBM). "In vitro" dissolution studies were performed with applications of the benign chemical, hydrogen peroxide (HP). PBM tubes were placed into ten chinchilla tympanic membranes matched with standard plastic tubes placed into the contralateral side. All 20 tubes were exposed to HP for 21 days with serial endoscopic examinations. In vitro PBM tubes were weighed before and after interventions and compared to control tubes. In vivo photo documentation was used to show progression of dissolution and histologic slides were obtained to show the effect of the PBM on surrounding tissues.

RESULTS

Compared to control tubes, all those exposed to hydrogen peroxide had a statistically significant reduction in weight (p < 0.01). After placement into the tympanic membrane of chinchillas, all PBM tubes dissolved within 21 days of hydrogen peroxide treatment leaving behind histologically normal, intact tympanic membranes.

CONCLUSION

Our PBM tubes dissolve "on-command" in a chinchilla model when exposed to treatment with a benign chemical. Dissolvable "on-command" tympanostomy tubes may reduce significant complications related to pediatric tympanostomy tube use.

Biocompatibility of "On-command" dissolvable tympanostomy tube in the rat model

OBJECTIVES/HYPOTHESIS

A prototype tympanostomy tube, composed of polybutyl/methyl methacrylate-co-dimethyl amino ethyl methacrylate (PBM), was tested to 1) evaluate the effect of PBM tubes on rat dermis as a corollary for biocompatibility and (2) to observe the efficacy of dissolution with isopropyl alcohol (iPrOH) and ethanol (EtOH).

STUDY DESIGN

Original animal experiment and bench testing.

METHODS

A two-part study was conducted to assess biocompatible substance with inducible dissolvability as a critical characteristic for a newly engineered tympanostomy tube. First, tympanostomy tubes were inserted subcutaneously in 10 rats, which served as an animal model for biosafety, and compared to traditional tubes with respect to histologic reaction. Tissue surrounding the PBM prototype tubes was submitted for histopathology and demonstrated no tissue reactivity or signs of major inflammation. In the second part, we evaluated the dissolvability of the tube with either isopropyl alcohol, ethanol, ofloxacin, ciprodex, water, and soapy water. PBM tubes were exposed to decreasing concentrations of iPrOH and EtOH with interval qualitative assessment of dissolution.

RESULTS

Histologic examination did not reveal pathology with PBM tubes. Concentrations of at least 50% iPrOH and EtOH dissolve PBM tubes within 48 hours, whereas concentrations of at least 75% iPrOH and EtOH were required for dissolution when exposure was limited to four 20-minute intervals.

CONCLUSIONS

PBM is biocompatible in the rat model. Additionally, PBM demonstrates rapid dissolution upon alcohol-based stimuli, validating the proof-of-concept of dissolvable on-command or biocommandible ear tubes. Further testing of PBM is needed with a less ototoxic dissolver and in a better simulated middle ear environment before testing can be performed in humans.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:956-961, 2017.

Comparison of Calcium and Barium Microcapsules as Scaffolds in the Development of Artificial Dermal Papillae

This study aimed to develop and evaluate barium and calcium microcapsules as candidates for scaffolding in artificial dermal papilla. Dermal papilla cells (DPCs) were isolated and cultured by one-step collagenase treatment. The DPC-Ba and DPC-Ca microcapsules were prepared by using a specially designed, high-voltage, electric-field droplet generator. Selected microcapsules were assessed for long-term inductive properties with xenotransplantation into Sprague-Dawley rat ears. Both barium and calcium microcapsules maintained xenogenic dermal papilla cells in an immunoisolated environment and induced the formation of hair follicle structures. Calcium microcapsules showed better biocompatibility, permeability, and cell viability in comparison with barium microcapsules. Before 18 weeks, calcium microcapsules gathered together, with no substantial immune response. After 32 weeks, some microcapsules were near inflammatory cells and wrapped with fiber. A few large hair follicles were found. Control samples showed no marked changes at the implantation site. Barium microcapsules were superior to calcium microcapsules in structural and mechanical stability. The cells encapsulated in hydrogel barium microcapsules exhibited higher short-term viability. This study established a model to culture DPCs in 3D culture conditions. Barium microcapsules may be useful in short-term transplantation study. Calcium microcapsules may provide an effective scaffold for the development of artificial dermal papilla.

Panel 7: Treatment and comparative effectiveness research

BACKGROUND AND OBJECTIVES

Otitis media (OM) is one of the most common reasons for antibiotic treatment in children. Controversies regarding antibiotic treatment for OM have accumulated in the past decade, and there seem to be more dilemmas than certainties. The objectives of this article are to provide the state-of-the art review on achievements in treatment of all different stages of OM, including acute otitis media (AOM), otitis media with effusion (OME), and chronic suppurative otitis media, and to outline the future research areas.

DATA SOURCES

PubMed, Ovid Medline, the Cochrane Database, and Clinical Evidence (BMJ Publishing).

REVIEW METHODS

All types of articles related to OM treatment published in English between January 2007 and June 2011 were identified. A total of 286 articles related to OM treatment were reviewed by the panel members; 114 relevant quality articles were identified and summarized.

RESULTS

New evidence emerged on beneficial results of antibiotic treatment, compared with observation of AOM in young children who were diagnosed based on stringent criteria. In OME, the main results were related to a nonsignificant benefit of adenoidectomy versus tympanostomy tube placement alone in the treatment of chronic OME in younger children. Other modalities of OM treatment were studied and described herein.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

Significant progress has been made in advancing the knowledge on the treatment of OM. Areas of potential future research have been identified and outlined.

Panel 8

Background and Objectives

Although serious complications of otitis media (OM) such as brain abscess are rare, sequelae of OM such as tympanic membrane perforation and atelectatic tympanic membrane are quite common. Inner ear sequelae can cause hearing loss and speech and language problems. The objectives of this article are to provide a state-of-the-art review on recent articles on complications and sequelae of OM in different anatomic locations, from the tympanic membrane to intracranial sites, as well as hearing loss and speech and language development.

Data Sources

Primarily PubMed supplemented by Ovid MEDLINE and the Cochrane Database.

Review Methods

All types of articles related to OM complications and sequelae published in English between January 2007 and June 2011 were identified. A total of 127 relevant quality articles are summarized and included in this report.

Results

Key findings are summarized based on the following major anatomic locations and categories: tympanic membrane; cholesteatoma; ossicular problems; mucosal sequelae; inner ear sequelae; speech and language development; extracranial areas, including mastoiditis and facial nerve paralysis; intracranial complications; and future research goals. New information and insights were gained to prevent complications and sequelae.

Conclusion and Implications for Practice

Over the past 4 years, progress has been made in advancing the knowledge on the complications and sequelae of OM, which can be used to prevent and treat them effectively. Areas of potential future research have been identified and outlined.

Behavior of poly(glycerol sebacate) plugs in chronic tympanic membrane perforations

The tympanic membrane (TM), separating the external and middle ear, consists of fibrous connective tissue sandwiched between epithelial layers. To treat chronic ear infections, tympanostomy drainage tubes are placed in surgically created holes in TMs which can become chronic perforations upon extrusion. Perforations are repaired using a variety of techniques, but are limited by morbidity, unsatisfactory closure rates, or minimal regeneration of the connective tissue. A more effective, minimally-invasive therapy is necessary to enhance the perforation closure rate. Current research utilizing decellularized or alignate materials moderately enhance closure but the native TM architecture is not restored. Poly(glycerol sebacate) (PGS) is a biocompatible elastomer which supports cell migration and enzymatically degrades in contact with vascularized tissue. PGS spool-shaped plugs were manufactured using a novel process. Using minimally invasive procedures, these elastomeric plugs were inserted into chronic chinchilla TM perforations. As previously reported, effective perforation closure occurred as both flange surfaces were covered by confluent cell layers; >90% of perforations were closed at 6-week postimplantation. This unique in vivo environment has little vascularized tissue. Consequently, PGS degradation was minimal over 16-week implantation, hindering regeneration of the TM fibrous connective tissue. PGS degradation must be enhanced to promote complete TM regeneration.