Ear Center: Hearing Results with the Kraus K-Helix Prostheses

Kraus K-Helix Clinical Study Results

Invention Timeline

  • Conception of invention: July 2007
  • US patent filed: February 2008
  • FDA approval: May 2008
  • First implant: July 2009

K-Helix Clinical Study: July '08 - Sept '09

Design

  • Prospective, non-randomized
  • Multi-center (2)
  • Multi-surgeon (3)
  • Endpoint = closure of Air-Bone gap (ABG)

Objectives

  • Reconstruct the long process of the incus
  • Increase reconstruction stability
  • Improve hearing: closure of the ABG to within 10 dB

Demographics

  • N = 8 (1 Male, 7 Females)
  • Age range = 36-81 years
  • Mixed hearing loss
  • Substantial absence of long process of the incus (3mm or greater)
  • Mobile stapes and malleus
  • Two groups:
    • Non-Chronic Ears: N = 3
    • Chronic Ears: N = 5

Method: Operation

  • Outpatient, general anesthesia
  • Single-stage procedures
    • Transcanal: N=7
    • Facial recess: N = 1
  • Cement (glass ionomeric)
    • Proximal coils and incus
    • Microdot(s) crown-to-stapes neck

Method: Surgical Procedure

  • Coils and crown adjusted as necessary, customized for the patient's anatomy
    • Spread
    • Removed
    • Dilated
  • Mucosa removed distal incus and stapes capitulum & neck; excess moisture removed
  • Proximal incus elongated with cement as needed; stapes capitulum created with cement, as needed
  • Coils "slid" over remaining proximal incus
  • Crown positioned on stapes capitulum; microdots of cement added
  • Data gathered and statistics reported as per AAO-HNS Protocol, Committee on Hearing and Equilibrium guidelines for the evaluation of results of treatment of conductive hearing loss. Otol Head Neck Surg, 113(3), 1995:186-187.
  • Data provided includes follow-up from 2-24 months

 

Intra-operative Images via OR Microscope: Participant 0203-104-06 Example, Left Ear

1. Left Ear: Ossicles exposed and stained                              2. Left Ear: Mucosa removed

    0203_104_06_ossicles_exposed          0203_104_06_mucosa_removed

3. Incus elongated with cement; capitulum created                 4. Cement applied to incus; microdots applied to capitulum

   Khelix_104_06_cement_implant        khelix_104_06_proximal_cement

 

Results: Kraus K-Helix Crown, Incus-to-Stapes

  1. Postoperative Air-Bone Gap in dB = combined closed within  5 dB

     khelix_results_ABG_graph        khelix_results_ABG_table

  2. Closure of Air-Bone Gap in number of dB = combined total 9 dB

     Khelix_closureABG_graph       khelix_closureABG_table

 

  3. Change in High Tone Bone Conduction (positive numbers reflect improvement in BC)

     khelix_hightone_graph        khelix_hightone_table

 

4. Change in Speech Reception Threshold (SRT) in dB = combined 24 dB increase

     khelix_SRT_graph        khelix_SRT_table

 

5. Change in Word Recognition Scores (WRS) in % dB = combined 15% improvement

     khelix_WRS_graph        khelix_WRS_table

 

6. Laser Doppler Vibrometry Frequency-Response Curves in Response to 100 dB SPL

  • Blue = baseline intact ossicular chain prior to disarticulation
  • Red = Kraus K-Helix Crown implanted incus-to-stapes, without cement
  • Yellow = Kraus K-Helix Crown implanted incus-to-stapes, with cement
  • Notice improvement in displacement at > than 1000 Hz as compared to motion of the intact ossicular chain

          khelix_LDV_freqresponse_graph

The clinical study is ongoing and results will be updated as data is gathered.

Results for the Kraus K-Helix Prostheses used for other ossicular reconstructions are in process:

  • Incus-to-Stapes (Kraus K-Helix Crown)
  • Malleus-to-Stapes (Kraus K-Helix Crown)
  • Incus-to-Footplate, mobile or fixed (Kraus K-Helix Piston)
  • Malleus-to-Footplate, mobile or fixed (Kraus K-Helix Piston)