Cochlear implants. Aaron G Benson MD Board Certified Otolaryngologist Board Certified Neurotologist

Transcription

1 Cochlear implants Aaron G Benson MD Board Certified Otolaryngologist Board Certified Neurotologist 1

2 OBJECTIVES WHAT IS A NEUROTOLOGIST WHAT MAKES AN INDIVIDUAL A COCHLEAR IMPLANT CANDIDATE WHAT IS THE DIFFERENCE BETWEEN A COCHLEAR IMPLANT AND A HYBRID IMPLANT 2

3 NEUROTOLOGIST 300 in the country Fellowship after completing ENT residency Has its own Board Certification 4 in the state of Iowa Specialize in Hearing Balance EARS!!!!! 3

4 4

5 Nucleus internal device 5

6 Ideal position 6

7 PROCESSOR Nucleus Freedom 7

8 William F. House First widespread clinical trials of cochlear implantation, 1980 As of December ,000 worldwide 110,000 US 58,000 adults 38,000 children 25-30% are second side 8

9 3 currently available systems Advanced Bionics Cochlear corporation Med-El 9

10 Advanced Bionics Processor: Naida CIQ 70 Implant: Hi Res 90k Electrodes: Hi Focus mid-scala and Hi Focus 1J 16 channels 8 paired so 120 virtual channels 10

11 Med EL Processor: Opus, Sonnet, Rondo Implant: Synchrony Electrode: Classic and flex. They offer different lengths 12 channels 11

12 Cochlear Processor: Nucleas 6 Profile Implant: Nucleas CI 124RE 22 channels 12

13 Electrode Arrays 13

14 14

15 15

16 Patient Selection Severe-profound sensory deafness Duration of deafness The shorter the time period the better Ideally don t want to implant if no aiding to the ear in 20 years Age at onset of deafness See above Young has greater brain plastisity 16

17 Patient Selection Postlingually deafened, unless very young Again refers to plastisity The ears have heard before Age at implantation Age 1 and beyond (younger have been done but no proven benefit) Greatest growth in elderly Oral communication 17

18 Cochlear implant candidacy Cochlear Implant: AZ-BIO Score no better than 50% in the ear to be implanted and no better than 60% in the best aided condition Moderate to profound sensorineural hearing loss in both ears

19 Pediatric criteria months Profound bilateral (>90dB) Confirmed with ABR and OAE Lack of progress auditory skill development Oral program rehab Minimal HA benefit with 3 month HA trial Questionnaire used to help assess 19

20 IT-MAIS IT MAIS Infant toddler meaningful auditory information score 10 questions (scored 0-4) Helpful for pre and post therapy 20

21 21

22 Exceptions Auditory Neuropathy Spectrum Disorder OAE present No abr Wave 1 of abr contains part of the cochlear microphonic Must run condensation and rarefication or alternating current to see this Cannot just reverse polarity or this will be lost No acoustic reflexes Criteria may be waived with ossification Missing cochlear nerve 22

23 23

24 Pediatric criteria 2-17 years old Severe-profound bilateral ABR OAE Standard audiometric testing Lack of progress auditory skill development, aided 6 months 24

25 Adult older criteria Unaided pure tones 500 hz,1000 hz and, 2000 hz better ear >70 db >90 db Medicare Can have retained low frequency Most important is discrimination score!!!!! 0-100% Determined using 1 syllable words like hat, cat. Given 40 db above threshold 25

26 HINT Best AIDED conditions This test uses common, simple sentences such as "How are you feeling?" or "The weather looks good today." HINT consists of 25 equivalent 10-sentence lists that may be presented in either condition (i.e., quiet, noise) to assess sentence understanding. 26

27 HINT The HINT test is first administered in quiet, using 2 lists of 10 sentences, scored for the number of words correctly identified. HINT in noise uses sentences administered at +10 signal to noise ratio (Sargent, 2000). 27

28 HINT Scoring Candidate <60% opposite ear or bilateral <50% implant ear <40% Medicare <30% for children Outdated Patients were scoring too well on this. Post implantation 71% scored 85% or higher 28

29 Adult newer criteria MSTB (minimal speech test battery) CNC (consonant-nucleas-consonant) Assess open set words 10 lists of 50 Monosylabic words Points for first consonant, middle vowel or end consonant EX Goose (3 points) 29

30 Adult newer criteria Used for the HYBRID 80%> in the contralateral ear 10-60% in the implant ear 30

31 Older pediatric and adult newer criteria MSTB (minimal speech test battery) AZ-Bio (Replaces the HINT) 4 Different talkers Conversational style Limited contextual cues Must fill in unintelligible words Can be presented in quiet or in a 10 talker babble at fixed signal to noise ratios This is what real life is like 8 lists of 20 sentences 31

32 AZ-BIO Scored like the HINT Administered at 60 db Candidate <60% opposite ear or bilateral <50% implant ear <40% Medicare <30% for children 32

33 CT and MRI Many prefer CT Ossification Congenital anomalies facial nerve T2 MR better to see cochlear fluids fibrous labyrinthitis (early) Lack of cochlear nerve 33

34 Contraindications Michel-cochlear aplasia Small IAC syndrome (maybe) CT criteria Can confirm this with MRI Active infections Congenital anomaly NOT a contraindication Worst patient-unaided prelingual manual teenager,deaf parents, now wants an implant for hearing girlfriend 34

35 Side of implantation Most patent cochlea Less infected ear or cavity Shorter duration of deafness Worse or better ear? 35

36 Bilateral implantation Simultaneous or sequential Time between implantation Operative time in very young or high risk Does better ear have any residual heaing? 36

37 Bilateral implantation 4 advantages of normal stereophonic hearing Eliminate -6dB head shadow 50% of time Determine direction, distance sound Enhanced signal/noise ratio Increased dynamic range 37

38 Surgery Minimal access Incision 1-2cm from implant Plan space for bte processor Flap thickness 6-7mm Leave temporalis with flap in young 38

39 mastoidectomy 39

40 Facial recess 40

41 Position of cochlea, Right 41

42 Cochleostomy, more inferior 42

43 Avoid hook of cochlea 43

44 Soft surgery, atraumatic modiolar hugging electrodes 44

45 X-ray if uncertain or anomaly 45

46 46

47 Cochleastomy Current controversy about where and how to do this Round window insertion True cochleastomy Soft technique What I do Steroids Allows you to save hearing! 47

48 Neural response telemetry Allows verification of neural response in the O.R. Starting point for programming 48

49 Complications Incision/flap problems most common CSF leak, gusher Malformed ears lateral IAC WVA Infection Facial paralysis 49

50 Meningitis <1% Very young Positioner cases Malformed inner ear Previous meningitis Prevnar (7), Pneumovax (23valent) Prevnar if 2> Pneumovax 5< 2 weeks prior to surgery 50

51 Meningitis Otology and Neurotology July 2013 page 845 Author Marteen Van Loon 5-36% of patient post bacterial meningitis will have SNHL 3-9% will have bilateral severe hearing loss or deafness hearing loss can be present as soon as 2 days after onset of meningitis 51

52 Meningitis If obliteration of the cochlea occurs it usually starts with the first week after the onset of meningitis Ossification of the cochlea can be complete within months T2 MRI visualizes fluid within the cochlea and can detect early narrowing or obliteration of the cochlea lumen 52

53 Meningitis Sensitivity of T2 MRI is 92% even if the cochlea is obliterated with MRI some patients were able to be successfully implanted T1 with gadolinium reveals increased perfussion to the striae vascularis. This enhancement has a high degree of correlation with hearing loss 53

54 54

55 55

56 Drill beyond ossification 56

57 Device failure Immediate intraoperative NRT impedences Intermittency Hard (device is hit and no longer works) Soft (subtle) Delayed decreased performance Delayed pain or tenderness Integrity testing 57

58 Adult Results >70% adults open set 2/3 telephone use Duration deafness most important 58

59 Pediatric results Age at implantation most important 3 or younger at implantation best 9/10 children implanted early use telephone, attend mainstream schools 59

60 Hybrid Implantation If that wasn t enough to remember! Now there are expanded indications 60

61 Cochlear implant candidacy Cochlear Implant: AZ-BIO Score no better than 50% in the ear to be implanted and no better than 60% in the best aided condition Moderate to profound sensorineural hearing loss in both ears

62 Implanted Ear: CNC between 10% and 60% Normal to moderate SNHL in the low frequencies PTA of 2k, 3k, 4k > 75 db HL Contralateral Ear: Would need to be better than 60 at low and worse then 60 high CNC 80%> 62

63 Hybrid Hearing Zone Post Implant Thresholds: Pure tone thresholds <85 db HL anywhere between 250Hz Hz are candidates for hybrid hearing. IF YOU SPARE HEARING!!!!! Only true up to 60% of cases

64 64