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Middle Ear Implants: Concepts and Implementations. Jonathan H. Spindel, Ph.D. College of Integrated Science and Technology James Madison University, Harrisonburg, Virginia http://sharepoint.cisat.jmu.edu/isat/spindejh/presentations e-mail: spindel@cisat.jmu.edu. What is an MEIHD?.
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Middle Ear Implants: Concepts and Implementations Jonathan H. Spindel, Ph.D. College of Integrated Science and Technology James Madison University, Harrisonburg, Virginia http://sharepoint.cisat.jmu.edu/isat/spindejh/presentations e-mail: spindel@cisat.jmu.edu
What is an MEIHD? A hearing amplification device in which vibrational energy is delivered to the ear using implanted components. Different from a cochlear implant: • Residual cochlear function is utilized • IHD sensation is “sound-like” Different from bone vibrators (i.e. BAHA): • Better potential for high gain application • Capable of providing wide-band amplification
IHDs: Design Considerations • Addresses feedback, occlusion, distortion • Preserves residual hearing • Minimal risks (surgery, infection) • Cost-effective (over the life of the device) • Permits the full range of normal activities • Improves the user’s quality of life…
NOTE: Conventional hearing amplification is not viable for many patients due to… Tortuous and small ear canals Unmanageable feedback Chronic EAC issues Irritation, swelling & pain, infection, contact dermatitis Unacceptable fit Chronic cerumen production Environmental factors that prevent HA use Unresolved issues in conductive hearing loss
Investigation Teams: Ball et al. Dumon et al. Fredrickson et al. Goode et al. Hough et al. Hüttenbrink et al. Kartush and Tos Maniglia et al. Snik et al. Spindel et al. Suzuki et al. Tjellstrom et al. Welling and Barnes Yanagihara et al. Industrial Ventures: Implex Nobel Industries Otologics Resound Rian Richards Smith and Nephew SoundTec St. Croix Medical Med El (Symphonix) Xomed-Treace IHD R&D: Past and Present
Envoy Medical (“Esteem” – TIMEIHD) Images courtesy of Envoy Medical
Status Check: Envoy Medical • Feasibility trial complete • Proved concept • Improved design of components (titanium and gold, hermeticity) • Increased robustness of system • Pivotal (PMA) trial currently underway (expect PMA in Fall 2006) • 7 US sites (5 current), 4 German Sites • 50 to 75 subjects to be implanted (45 (38 on), 30-35 pending surgery) • Of current subjects: 4 US / 1 EU ~27 dB average at 500, 1k, 2k • Minimal data reported to date
Images courtesy of Otologics
Implant Microphone Digital Signal Processor Battery IS-1 Connector Lead Receiver Coil Magnet Transducer
Implant Charger • Recharges battery of implant • Daily recharge takes of approximately 1 hour • Patient can use implant during recharge Base Station • Charges implant charger Remote Nominal Operating Parameters • Battery life: > 12 years• Battery recharge time: 60 minutes (typical)• Battery recharge frequency: daily• Peak Output: 121 dB MET• Frequency Range: < 200 to 6250 Hz• Processor Type: 12 Band, 2 Ch. DSP
Status Check: Otologics • Phase I clinical trial in US (9 subjects completed 2001) • CE Mark obtained July 2001 • Initiated Phase II trial in US (n = 104) • April 2003 voluntary suspended US clinical trial and ceased sales in the EU • Problems were identified centered around: Fragility/Reliability of the Transducer • Could be damaged during manufacturing, shipping, implanting Coupling/Loading difficult for Surgeons • Too little loading = poor patient benefit/limited gain • Too much loading = conductive loss and/or Transducer Damage • New surgical instrumentation introduced to address problems • EU sales resumed September 2003 • Decision to re-enter the world market with a totally implantable version • Currently 61 TI devices have been implanted (20 US, 41 EU/Asia)
Vibrant Soundbridge Audio Processor VORP Floating Mass Transducer Images courtesy of Vibrant Med-El
Status Check: Vibrant Med-El • First patient implanted in EU in Sept. 1996 • First patient implanted in US in October 1996 • US clinical trial (100 patients) completed Summer 2000 • FDA approval Summer 2000 • Patients world-wide (>2000) • Multi-center clinical data presented in O-H&NS (Feb 2002) • >100 bilateral Vibrant patients (WW) • “Vibroplasty” study initiated this year to explore use in conductive loss
Reported patient selection criteria for Esteem, MET and Vibrant products(Note: Vibrant data includes proposed expansion pending FDA approval)
A round window implantable hearing device using a floating mass transducer
Development of a round window implantable hearing deviceJonathan H. Spindel, Paul R. Lambert, Roger A. Ruth(contributions by Michael A. Fuller)Department of Otolaryngology-HNS, University of Virginia, Charlottesville, Virginia, USADepartment of Integrated Science and Technology and Department of Communication Sciences and Disorders, James Madison University, Harrisonburg, Virginia, USA
RWEM An electromagnetic approach using a magnet applied to the round window membrane.
The RWEM concept... direct vibrational input to the cochlea no disarticulation or potential ossicular erosion
ACOUSTIC RWEM RWEM ACOUSTIC Frequency-Specific ABR (Threshold Measures)
Energy transfer to the cochlea using a round window implantable hearing device(a temporal bone study)Jonathan H. Spindel1 and Geoffrey Ball2Department of Integrated Science and Technology and Department of Communication Sciences and Disorders, James Madison University, Harrisonburg, Virginia, USA 1Institute for Applied Physics, University of Innsbruck, Innsbruck, Austria 2
A FMT on the round window can be used to develop higher gain device along with providing for alternative therapy options for problematic middle ear anatomies and inoperable conductive hearing loss
Hypothesis Placement of a transducer closer to the cochlea will maximize energy transmission to the cochlea.
TB ER-2 LDV ER-7C
EAC Acoustic Stimulus ER-7C LDV ER-2 EAC Middle Ear OW RW LDV
I-FMT Stimulus ER-7C LDV EAC Middle Ear OW I-FMT RW LDV
RW-FMT Stimulus ER-7C LDV EAC Middle Ear OW RW-FMT RW LDV
Results Summary: RW-FMT • The RW-FMT is a viable implant approach • The FMT on the round window creates greater displacement of the cochlear fluid than the incus-mounted FMT
Next steps… • Investigate the RW-FMT clinically in a selected subject pool to ensure a standardized data set for evaluation (Med El vibroplasty study) • Provide regular and long-term measures to prove efficacy over time (Med El vibroplasty study) • Develop comparative result measures to support the utility of this approach compared to standard reconstructive procedures and BAHA • Use data to develop recommended surgical procedures that maximize device stability and performance for wider surgical use
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