Project Summary/Abstract: The objective of this proposal is to create a new low-cost, needle-sized steerable endoscope that makes it possible to survey and diagnose middle ear disease using a minimally-invasive trans-Eustachian tube approach, sparing patients from invasive surgery. Clinical significance comes from the 84,000 surgeries per year (in the USA alone) performed on patients who suffer from a middle ear disease called cholesteatoma that requires exploratory surgery for diagnosis, which is currently achieved surgically by lifting the eardrum to expose the middle ear space. Surgery is currently the only definitive way to diagnose these patients. Worse yet, a second surgery is performed to check for recurrence a year later – even though 67% of patients will be disease free at that time. We seek to replace surgical inspection with a simple endoscopy, facilitated by our new ultra-thin steerable endoscope passed through the Eustachian tube. Our central hypothesis is that our new trans-tubal endoscopic approach can achieve diagnostic visualization of the middle ear equivalent to that provided by surgery today. This has the potential to spare many patients from the pain and complications associated with surgery, by replacing it with a simple endoscopy done through the nose. Innovation comes from harnessing elastic interactions in asymmetrically stiff, thin-walled tubes to create a steerable endoscope that is (1) small enough to pass through the Eustachian tube, while (2) carrying a tiny camera and optical illumination fibers within its own central lumen. The small diameter of the Eustachian tube precludes the use of bulky standard endoscope steering mechanisms. Instead, we harness stiffness asymmetry encoded into the material properties of two tubes that are attached at their tips, thereby transforming small axial motions applied at the endoscope handle into dexterous local bending at the endoscope tip. The result is an inexpensive, needle-sized, disposable, steerable endoscope for trans-tubal visualization of the middle ear. Our approach in Aim 1 is to use laser micromanufacturing and catheter-inspired design processes to fabricate a clinic-ready steerable endoscope tip with integrated imaging and illumination. Aim 2 incorporates rigorous quality and human factors-based design enhancements, preparing our device for FDA 510(k) clearance review immediately at the end of Phase II. Aim 3 focuses on statistically powered experiments to evaluate our hypothesis that our new steerable aiming tip will enable middle ear inspection and cholesteatoma diagnoses to be performed using a non-surgical, trans-Eustachian tube approach, with equal diagnostic-quality visual coverage compared to the surgical standard-of-care. Success in validating these hypotheses will strongly motivate future Phase III activities (supported by private capital after the conclusion of this Phase II SBIR) where we complete the FDA 510(k) clearance process, and launch our device on the ma...