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Real Time Measurements of Tympanic Membrane and Middle Ear Mechanics

Description:

TECHNOLOGY AREA(S): Bio Medical 

OBJECTIVE: The intent of this SBIR is to develop a medical device that can provide real time analysis of middle ear mechanics, measure the defect to bridge the ossicular reconstruction and measure the tension on the repaired tympanic membrane intraoperatively 

DESCRIPTION: The ongoing conflicts in Asia as result in numerous service members sustaining blast injury to the tympanic membrane. The morbity results in hearing loss and in many patients requires surgical repair. The post-operative hearing result remains less than ideal for our services members. The modern era of tympanoplasty was ushered in by Wullstein and Zollner. Tympanomastoid surgery is quite successful in controlling infection and preventing recurrent disease, with reported success rates in excess of 80–90%. However, it is well recognized that post-operative hearing results are often unsatisfactory, especially in cases with advanced lesions of the ossicular chain or those with nonaeration of the middle ear. As when, the ossicular chain has to be reconstructed, long-term closure of the air-bone gap to < 20 dB occurs in 40–70% of cases when the stapes is intact, and in only 20–55% when the stapes superstructure is missing. Otologic surgeons have a good general appreciation of various anatomical and pathological reasons for failure of tympanoplasty, such as nonaeration of the middle ear, abnormalities of the reconstructed TM and inefficient sound transmission via the reconstructed ossicular chain. However, a quantitative understanding of the acoustical consequences of structural variations of a reconstructed ear is generally lacking. Liston et al., used intra-operative auditory evoked responses during ossiculoplasty and found that minor changes in prosthesis positioning on the order of 0.5–1.0 mm had relatively large effects on hearing (varying up to 20 dB). A clinical observation that postsurgical ears that seem almost identical in structure may demonstrate markedly differing degrees of conductive hearing loss. Small changes in structure have the capacity to have large effects on function. This is also important because small changes in graft and prosthesis position can occur as part of the healing process, which is beyond control of the otologic surgeon. There are major deficiencies in the quest to improve post-tympanoplasty hearing results. There is lack of quantitative understanding of middle ear mechanics, acoustics in the reconstructed middle ear and tension on the repaired tympanic membrane with real time acoustic knowledge. 

PHASE I: Phase I will focus on designing a prototype and determining the technical feasibility of creating a medical device that has the potential to acquire tympanic membrane and middle ear biomechanics perioperatively. The device will include tension measurement on the tympanic membrane intraoperatively, determine ossicular mobility and as well as appropriate length of ossicular prosthesis. Implement the current knowledge of biomechanics of the ear into the device. Perform modeling on per and post-operative surgical outcomes using available technology. Demonstrate product design features and establish performance goals. Provide detailed information on data variables on tympanic membrane and middle ear biomechanics. Estimate the cost of such a device and its usability within the current operative environment within roles 3 and 4 care in the Military Health system. Define the potential risk of using such a device intraoperatively due to technology during development (laser, optical, heat transfer). 

PHASE II: Based on the product from Phase 1 design is to produce a prototype that can then be validated using animal models or cadaveric model. Demonstrate accurate and real-time measures of the tympanic membrane per operatively and post operatively. Validate hearing outcome measures using middle ear biomechanics measurements. The device may integrate with current surgical equipment. There should be consultation with otologic surgeon during design validation. Phase II should outline an FDA regulatory plan. The organization will engage potential partners or consultants for clinical testing.  

PHASE III: During Phase III, additional experiments will be performed as necessary to prepare for FDA approval. It is required that this device to commercialized and made available to the military health system which may include combat trauma acute rehabilitation with levels 3 and 4 of care. A detailed market analysis will be conducted and acquire potential private funding for commercialization. The device will be utilize peri-operatively for surgical planning and intra operatively to improve ossiculoplasty outcomes. 

REFERENCES: 

1: Dornhoffer JL, Gardner E. Prognostic factors in ossiculoplasty: a statistical staging system. Otology and Neurotology. 2001

2: 22:299–304

3:  Mishiro Y, Sakagami M, Adachi O, Kakutani C. Prognostic factors for short- term outcomes after ossiculoplasty using multivariate analysis with logistic regression. Arch Otolaryngol Head Neck Surg. 2009

4: 135:738–41

5:  Liston SL, Levine S.C., Margolis RH, et al. Use of introperative auditory brainstem responses to guide prosthesis positioning. Laryngoscope 1991

6: 101:1009-12

7:  Aarnisalo, A.A., Cheng, J.T., Ravicz, M.E., Furlong, C., Merchant, S.N., Rosows‘ki, J.J., 2009. Motion of the tympanic membrane after cartilage tympanoplasty determined by stroboscopic holography. Hearing Research 263 (1–2), 78–8

8:  Rosowski, J.J., Mehta, R.P., Merchant, S.N., 2004. Diagnostic utility of laser-Doppler vibrometry in conductive hearing loss with normal tympanic membrane. Otology & Neurotology 25 (3), 323–332

KEYWORDS: Ossiculoplasty, Middle Ear Mechanics, Biomechanics, Tympanic Membrane 

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