Tympanic membrane perforations are commonly seen in otology practices and about 150,000 repair surgeries are performed each year in the United States. Current office-based procedures such as paper patch tympanoplasty are relatively ineffective or, like the irritant oil method, require multiple office visits. Surgical procedures including fascia and cartilage tympanoplasty are more effective but are invasive and expensive. One of the simplest and most effective methods of tympanic membrane repair involves insertion of a bobbin- shaped hydrogel construct across the membrane. Previous attempts to use hydrogels to create bobbin-shaped constructs have involved use of either molded collagen or calcium alginate, but neither of these has been commercialized. The main barriers to commercialization of molded hydrogel constructs are poor mechanical integrity and handling characteristics, lack of cost-effective sterilization methods, difficult manufacturing techniques and inconsistent part dimensions. This study proposes to overcome these barriers by assessing the feasibility of using novel molding techniques to form constructs from two different hydrogel materials. Calcium alginate manufacturing will be streamlined using irreversible thermal gelation with calcium chloride-loaded liposomes. These will be compared to constructs made from concentrated solutions gellan gum, the processing of which is leveraged from knowledge gained by Grace Medical during development and regulatory approval of gellan gum temporary ocular inserts. Analysis of the two materials will include full chemical characterization. The results of the tests will allow a determination based upon cost, performance and manufacturability of the best material to use for in vitro and in vivo biocompatibility testing in Phase II of the project.
This project is intended to benefit those that require repair of the tympanic membrane due to rupture or incomplete healing following removal of tympanostomy tubes. The work will develop an inexpensive, commercially viable tympanic membrane repair construct that will transform tympanoplasty into a minimally invasive, routine and widely-practiced office-based technique. The tympanic membrane repair constructs can drastically reduce cost and improve outcomes as it will replace current, relatively ineffective office-based techniques or effective but expensive operating room-based techniques with a simple 10 minute procedure.