Advancing Pediatric Tympanoplasty with 3-Dimensionally Printed Eardrums

Key Words: Eardrum, Tympanoplasty, Chronic otitis media, Hearing loss, Mechanics of hearing

Perforations of the eardrum occur as a result of chronic ear infections, trauma or blast injury and annually affect millions of pediatric and adult patients worldwide. Patients suffer from ear pain, hearing loss, speech and language delay as well as decreased quality of life. The repair of the eardrum (tympanoplasty) is a common surgical procedure that typically utilizes harvested (autologous) tissue from the patient to heal the perforation; however, graft failure and persistent conductive hearing loss are frequent surgical outcomes, especially in children. Systematic reviews find failure rates using autologous grafts in 15-20% in children. Given limitations of current graft materials there is a need to modify tympanoplasty grafts to improve post-operative TM perforation closure and hearing outcomes. Advances in the field of 3D printing may provide solutions to persistent healing and hearing challenges in tympanoplasty. Specifically, advanced 3D printing techniques now permit creation of bioabsorbable grafts to recapitulate a ‘biomimetic’ eardrum. We hypothesize that 3D printed grafts will 1) integrate with the remnant TM to consistently close chronic perforations, and 2) establish ‘biomimetic’ architecture that transmits sound energy similar to the normal eardrum.

The aims of this study are to: 1) determine efficacy of 3D printed grafts to heal chronic TM perforations and 2) determine bioacoustics properties of 3D printed TM in vivo. An assessment of perforation closure using a chronic TM perforation animal model will describe the efficacy of 3D printed grafts in TM repair. The primary outcomes of AIM 1 are the rate of perforation closure and histologically assessed graft integration. While perforation closure is critical, restoration of conductive hearing is of equal importance. Experiments in AIM 2 measure hearing following tympanoplasty with 3D printed graft materials. The primary outcomes of AIM 2 are auditory brainstem response, and acousto-mechanical measurements of reconstructed TMs.