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

Kraus K-Helix Clinical Study Results

Invention Timeline

  • Conception of invention: July 2007
  • U.S. Patent #8,057,542 B2. Ossicular Prosthesis Having Helical Coil.
    Date of patent = November 15, 2011. Int. Cl. A6IF 2/18, H04R 25/00, U.S. Cl. 623/10; 600/25. Field of Classification Search 623/10; 600/39, 25.
  • FDA approval: May 2008
  • First implant: July 2009

K-Helix Clinical Study: July '08 - Sept '15

Design

  • Prospective, non-randomized
  • Multi-center (2)
  • Multi-surgeon (2)
  • 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 = 20 (4 Male, 16 Females)
  • Average Age = 37.4 yrs (range 6-81 yrs)
  • Mixed hearing loss in all patients
  • Pathology
    • Substantial absence of long process of the incus (3mm or greater) in all patients (N=20)
    • TM Perforations = 6
    • Atelectatic TMs = 14
    • Cholesteatoma = 8
  • Mobile stapes and malleus
  • Titanium K-Helix Crown implanted incus-to-stapes

Method: Operation

  • Outpatient, general anesthesia
  • Single-stage procedures (often combined with a mastoidectomy)
  • Eroded incus usually augmented (precoated) with glass ionomer cement
  • Titanium K-Helix Crown implanted incus-to-stapes, custom-fitted (prosthesis manufactured by Grace Medical)
  • Cement (glass ionomers: Fuse and ProCem 2)
    • 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 using sterile medical air delivered throught #18 gauge Barron suction tip
  • Proximal incus elongated with cement (precoated) 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 1 - 6 years (mean 3.17 yrs)

Follow-up: 1 - 6 years (mean 3.17 years)

Results, Incus-to-Stapes:

  • PTA (500, 1000, 2000, 3000 Hz) increase = 29 dB
  • ABG closed to within = 8.41 dB
  • Increase SRT = 26 dB
  • No loss of high tone bone conduction
  • Long-term follow-up = stable
    • No TM perforations
    • No granulation tissue
    • No extrusions
  • Alternative to conventional interposition, PORPS, I-S prostheses

 

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

 

1- 6 year Results: Kraus K-Helix Crown, Incus-to-Stapes, Chronic Ears

 

 1. Mean Pure Tone Average in dB ( Average of 500, 1000, 2000, 3000 Hz) = 29 dB

khelixcrown_is_PTA

 

2. Postoperative Air-Bone Gap in dB = combined closed within 8.41 (N=20)           

khelixcrown_is_MeanABG

 

  3. Closure of Air-Bone Gap in dB = (Preoperative ABG - Postoperative ABG)

          khelixcrown_is_MeanCalABG

 

  4. Change in High Tone Bone Conduction = (Average of 1000, 2000, 4000 Hz)
*Note - positive numbers reflect improvement in BC

           khelixcrown_is_ChangeHTBC

 

5. Change in Speech Reception Threshold (SRT) in dB = 26 dB    

khelixcrown_is_ChangeSRT

 

6. Change in Word Recognition Scores (WRS) in % dB = 5% increase
*Note - negative number represents increase

           khelixcrown_is_ChangeWRS

 

7. 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.

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

  • Incus-to-Stapes (Kraus K-Helix Crown) in non-chronic ears (Esteem II explants)- in process
  • Malleus-to-Stapes (Kraus K-Helix Crown) - in process
  • Incus-to-Footplate/Neomembrane, mobile or fixed, (Kraus K-Helix Piston) - particularly useful in revision stapedectomy
  • Malleus-to-Footplate, mobile or fixed (Kraus K-Helix Piston) - in process

References

1. Kraus EM, Christopher JY. Endoskeletal Ossicular Reconstruction Using the Kraus K-Helix Crown and Piston Middle Ear Prostheses. ORL Head Neck Nursing 2010;28(4):8-16.
2. Berenholz LP, Burkey JM, Lippy WH. Hearing results in reconstructing the damaged incus with varying lengths of the modified Lippy prosthesis. Otol Neurotol 2011;32 (January):17-20.

Last revised September 11, 2015