Cochlear Implant complete presentation by Dr Salison Salim Panicker

all about cochlear implant, use , selection criteria, complications, equipment , activation, other implants, future. prepared by Dr Salison Salim Panicker ( ENT surgeon , Thrissur - Relentcare clinic)

1. Cochlear implant Dr Salison Salim Panicker Dr A.K Mehta

2. BACKGROUND/INTRODUCTION /PATHOLOGY HISTORY COMPONENTS, MECHANISM, TYPES CANDIDATE SELECTION SURGICAL ASPECTS POST OPERATIVE ISSUES RECENT ADVANCES AND FUTURE DEVELOPMENT

3. BACKGROUND COCHLEAR IMPLANTATION A ROUTINE PROCEDURE FOR MANAGEMNT OF SEVERE -TO-PROFOUND SENSORINEURAL HEARING LOSS COLLABORATION BETWEEN ENGINEERS, SURGEONS, SCIENTISTS AND THE MEDICAL COMMUNITY

4. INTRODUCTION A cochlear implant is an electronic device, that bypasses the damaged hair cells of the cochlea and stimulates the auditory nerve directly It’s a Electromechanical transducer The first true bionic sense organs – SO CALLED BIONIC EAR Internal device- interfaced with the cochlear nerve External device- uses a specific speech coding strategy to translate acoustic information into electric stimulation

5. PATHOLOGY Direct or indirect injury to the organ of Corti Degeneration or dysfunction of the hair cell system Success of cochlear implantation- surviving spiral ganglion neurons Number of surviving neurons needed for successful implantation remains unclear 10-70% of the normal 35,000-40,000 cells

6. Normally approx. 35,000 nerve fibres and minimum of 10,000 spiral ganglion cells required for preservation of speech recognition No significant correlation between total spiral cells count {some study} No relation with depth of insertion with performance

7. HISTORY 1790 – ALESSANDRO VOLTA EELCTRIC signal auditorsystem creating perception of sound 1961- Dr William F House , james doyle {n} , john doyle {e} single channel device named HOUSE/3M , around 1000 implanted {1972-1980} Multichannel was introduced in 1984 Cochlear implant in india by Prof.Mohan Kameshwaran in 1996 at MERF

8. COCHLEAR IMPLANT DEVICES AVAILABLE There are currently three CI systems in widespread use at present worldwide: 1. Cochlear system , produced by Cochlear Ltd of Sidney, Australia ; 2. Med-El system produced by Med-El of Innsbruck, Austria ; 3. Clarion system , produced by Advanced Bionics of California, USA .

9. SIMILARITIES BETWEEN THE THREE COCHLEAR IMPLANT SYSTEMS Multichannel stimulation Transcutaneous communication Intergrity of intracochlear electrodes monitored by telemetry Range of speech processing startegies Programing of speech processor cost

10. COMPONENTS OF COCHLEAR IMPLANT EXTERNAL PARTS MICROPHONE SPEECH PROCESSOR TRANSMITTER INTERNAL PARTS RECIEVER AND STIMULATOR AN ARRAY OF ELECTRODS UPTO 22

11. SOUND ARE PICKED BY MICROPHONE SIGNAL IS CODED {TURNED TO SPATIAL PATTERN OF ELECTRIC PULSES} to provide a accurate description of sound to brain PULSES SENT TO COIL AND TRANSMITTED ACROSS SKIN TO IMPLANT IMPLANT SENDS A PATTERN OF ELECTRIC PULSES TO ELECTRODES IN COCHLEA AUDITORY NERVE PICS THE PULSES AND SENT THEM TO BRAIN

12. INSERTION DEPTH The mean length of human cochlea is 33-36mm. The implants don’t reach to the apical tip. It may reach up to 25mm which corresponds to a tonotopical frequency of 4000hz.

13. TYPES OF COCHLEAR IMPLANT SINGLE VS MULTIPLE CHANNELS EARLY IMPLANTS- ONE ELECTRODE/ONE CHANNEL{USED BY WILLIAM HOUSE AND JOHN DOYLE} RECENT ONES- MULTIPLE ELECTRODES (22) MULTIPLE CHANNELS (4-8) RESULTS OF MULTICHANNEL CI BETTER THAN SINGLE CHANNEL Advantages of Multichannel and Multiple Electrode Cochlear Implants: Improved Frequency Resolution: The ability to stimulate different regions of the cochlea independently allows for better separation and perception of different frequencies. Enhanced Speech Perception: Multichannel implants can improve the clarity of speech by providing more detailed information about the various components of speech sounds. Better Music Perception: Multiple electrode arrays can contribute to a more natural representation of music, allowing users to appreciate melody, harmony, and rhythm more effectively. Spatial Hearing: Having multiple electrode arrays can contribute to improved spatial hearing, allowing users to better locate the direction of sounds in their environment. Individualized Programming: The ability to individually program each electrode provides greater flexibility in optimizing the implant's performance for each user.

14. COCHLEAR IMPLANTS Straight , flexible electrode arrays Precoiled Less traumatic Focused

15. MODES OF STIMULATION ELECTRIC STIMULATION- COMPLETE ELECTRIC STIMULATION WHERE THE RESIDUAL HEARING IS NOT CONSIDERED AND MAY BE DESTROYED DURING INSERTION ELECTROACOUSTIC STIMULATION- HYBRID IMPLANTS , BIMODAL STIMULATION- ONE EAR USE IMPLANT WHILE OTHER USES HEARING AID BILATERAL COCHLEAR IMPLANT FOR 1 LOCALIZATION, 2 HEAD SHADOW EFFECT{6 dB LOSS} , 3 SQUELCH ,4 SUMMATION BILATERALLY LINKED AUTOMATIC GAIN REQUIRED IN BIMODAL OR BILATERAL IMPLANTS

16. TYPES OF COCHLEAR IMPLANTS MONOPOLAR VS BIPOLAR MONOPOLAR- ONE GROUND ELECTRODE FOR ALL BIPOLAR- GROUND FOR EACH ELECTRODE IS ADJACENT TO OR FEW ELECTRODE AWAY

17. CODING STRATEGY Method by which pitch, loudness , timing of sound are translated into a series of electrical impulses SIMULTANEOUS NON-SIMULTANEOUS Concept of simultaneous or sequential stimulation can be inferred from how cochlear implants work. In a cochlear implant, multiple electrodes may be activated simultaneously to convey different aspects of sound, such as pitch and intensity.

18. CODING STRATEGY SIMULTANEOUS Activation of more than one electrode at the same time Improved speech outcomes, a more natural quality of sound Potential “channel interaction” CONTOUR{COCHLEAR} HELIX{ADVANCED BIONICS}

19. NON-SIMULTANEOUS Continuous interleaved sampling{CIS} strategies stimulate each electrode serially. NO ELECTRODE IS BYPASSED. Each electrode stimulates a different frequency within the cochlea cochlea receives complete information about the frequency composition about incoming signal FASTER SEQUENTIAL STIMULATION-BETTER SPEECH RECOGNITION MEDEL/COCHLEAR/NUCLEUS

20. Electrode Array CONSIST OF ELCTRODE AND ELECTRODE CARRIER ELECTRODE CARRIER IS THE WIRE EXTENT FROM RECIEVER TO ELCTRODES 2 TYPES EXTRACOCHLEAR AND INTRACOCHLEAR; EAR ELECTRODES EXTRA COCHLEAR ELECTRODES- LOCATED OUTSIDE THE COCHLEA SUCH AS ON THE PLATE OF RECIEVEING COIL OR PLACED UNDER THE TEMPORALIS MUSCLE, USED AS A GROUND SOURCE FOR MONOPOLAR STIMULATION

21. Modiolus hugging electode Modiolus – core of cochlear spiral-ganglion cells resides there. Place with stylette – keep the electrodes stiff- easily inserted- stylette withdrawn-springs back into its orginal configuration- tightly around the modiolus. Toward a cochlear implant electrode array with shape memory effect for post‐insertion perimodiolar positioning

22. SPECIAL TYPES OF ARRAY Compressed array- number same, compact {60%}, can be used with cochlear anomaly/ labrynthine ossificans, less overlap of elctrodes Double array- Designed for subjects with labrynthine ossificans. Separate cochleostomies are performed into inferior and middle turns of cochlea

23. Patient Selection

24. Candidate Categories

25. Adults Cochlear implantation neither eliminates an underlying disease state nor restores normal function to the end organ of hearing. Therefore an objective view of risk/benefit ratios must serve to guide clinical decisions. Cochlear implantation was initially limited to BILATERAL postlingually deafened adults who received no benefit from hearing aids Implantation of an ear with any residual, aid able hearing carries the risk that the implanted ear could be made worse than that ear with a hearing aid.

26. Current investigations under US Food and Drug Administration (FDA) guidelines are having a hypothesis that an ear with some residual hearing may have a better neuronal population, increasing the likelihood of superior performance with a cochlear implant, especially with more complex multichannel stimulation. So the eligibility criteria for the procedure have been eased in light of recent research findings.

27. ADULTS -18 years old and older (no limitation by age) Bilateral severe-to-profound sensorineural hearing loss (70 dB hearing loss or greater with little or no benefit from hearing aids for 6 months) {1998} {FROM 2014 FDA }normal to moderate low frequency hearing(<60 dbHL ) sloping to severe (>=70 db HL) for hybrid/EAS devices, at low freq - hearing loss is less than 60db or. Normal at high freq – hearing loss is >70dB HL Moderate to profound for traditional devices. Single sided deafness and asymmetric hearing loss less than 10 year deafness. Speech perception :60 % in ear to be implanted and <80%contralaterally Psychologically suitable No anatomic contraindications Medically not contraindicated

28. CHILD 9 month {2020 FDA} and above Profound bilateral Unaided threshold greater than 90dbhl at 2000hz and above Aided hearing threshold in better ear >35dBHL especially at 4000HZ No response at ABR in both ear or no response is found for one ear and response of elevated level of other ear Single sided deafness and asymmetric hearing loss for ages 5+ with less than 10 year of deafness Progressive hearing loss near profound level at 2000hz and above Severely impairing auditory neuropathy

29. SPEECH PERCEPTION ADJUSTED{2019 FDA} TO INCLUDE “LACK OF AUDITORY PROGRESS” AND <30% OPEN SET M/LNT Of paramount significance is a commitment of the child's family and educational setting toward providing an appropriate environment and training setting.

30. PREOPERATIVE Radiologic examination of the cochlea is performed to determine if the cochlea is present and patent and to rule out a congenital deformity of the cochlea. High-resolution, thin section CT scanning of the cochlea along with MRI is the current imaging technique of choice.

31. Intracochlear bone formation as a result of labyrinthitis ossificans can usually be demonstrated by CT scanning. However, sclerosing labyrinthitis with soft tissue obliteration may not be accurately imaged. In these cases magnetic resonance imaging (MRI) is an effective adjunctive procedure to provide additional information regarding cochlear patency. T-2 weighted MRI will demonstrate loss of the endolymph/perilymph signal in sclerosing labyrinthitis.

32. High resolution CT scan has been the method of choice to demonstrate LO by ossification visualization within the otic capsule [1,7]. Ct – 50% chance to detect More recently, T2 MRI has shown high sensitivity (92.8%) and high positive predictive value (81.2%) to identify intra-cochlear LO.

33. Intracochlear ossification (labyrinthitis ossificans) is not a contraindication to cochlear implantation but can limit the type and length of the electrode array that can be introduced into the scala tympani of the cochlea ( Jackler et al, 1987b). When temporal bone fracture has resulted in deafness, CT scanning may provide valuable information predicting the integrity of the cochlear nerve. This may be confirmed by electrophysiologic testing

34. No upper age limit is currently used in the selection process. Cochlear implantation is appropriate if other selection criteria are met and the patient's general health will permit an elective surgical procedure under general anesthesia.

35. Audiologic assessment The audiologic evaluation is the primary means of determining suitability for cochlear implantation. PTA, TYMPANOMETYRY OAE,ABR AIDED THRESHOLD- Performance with an appropriate, high-power hearing aid is compared to expected performance with an implant.

36. Psychologic assessment Psychologic testing is performed for exclusionary reasons to identify subjects with organic brain dysfunction, mental retardation, undetected psychosis, or unrealistic expectations. Otologic assessment An otologically stable condition should be present before considering cochlear implantation in children. But still not a absolute contra-indication. Because children are more prone to otitis media than adults, justifiable concern has been expressed that a middle ear infection could cause an implanted device to become an infected foreign body requiring its removal .

37. Of even greater concern is that infection might lead to serious otogenic complication such as meningitis or further degeneration of the central auditory system. The management of middle ear effusions in children is needed. When it does not, treatment by myringotomy and insertion of tympanostomy tubes may be required. Removal of the tube several weeks before cochlear implantation will usually result in a healed, intact tympanic membrane before planned cochlear implantation. COM mucosal disease - tympanoplasty followed by cochlear implant after 3 months. COM squamosal disease - mastoidectomy followed by reconstruction and after few months Cochlear implant.

38. Medical Evaluation Clinical history, Preliminary examination Complete medical and neurologic examination Cochelar imaging using computed tomography (CT or magnetic resonance imaging (MRI) Vestibular examination ( electronystagmography ) Psychologic or psychiatric assessment or both Vision testing VACCINATION Assessment for anesthetic procedures Admission 1 day prior and Antibiotics

39. Contraindications Neurofibromatosis II, mental retardation, psychosis, organic brain dysfunction, unrealistic expectations Active middle ear disease. CT findings of cochlear agenesis (Michel deformity) or small IAC (CN8 atresia ) Dysplasia not necessarily a contraindication, but informed consent is a must H/O CWD mastoidectomy Advanced cochlear otosclerosis {now cochlear implant is a treatment for same}

40. Type of bacterial meningitis Vaccines that help protect against it H. influenzae  type b (Hib) meningitis Hib conjugate vaccines Meningococcal meningitis Meningococcal conjugate (MenACWY) vaccinesSerogroup B meningococcal (MenB) vaccines Pentavalent meningococcal (MenABCWY) vaccine Pneumococcal meningitis Pneumococcal conjugate vaccines (PCVs), including PCV15 and PCV20, Pneumococcal polysaccharide vaccine (PPSV23)

41. VACCINATION – CDC[centre for disease control and prevention] recommendation PPV-23(pneumococcal polysaccride vaccine) PCV-13(pneumococcal conjugated vaccine) Children<2yrs –receiving implant should receive pcv13 Children more than 2 years who have complete , PCV 13 should receive PPV23 All childern should receive 3 dose of peumococal conjugated vaccine before 1 Child 24-59 month with no PCV 13 should have, PCV 13 2 month apart and 1 dose PPV 23 2 month later Children who have completed the PCV13 seroes should receive PPV23>2 month after vaccination with PCV13 Persons aged 5-64 years should receive PPV23 a single dose is indicated. MORE THAN 2 WEEKS BEFORE ALL VACCINE SHOULD BE DONE.

42. Children younger than 5 years old should be up to date on Hib vaccination at least 2 weeks before cochlear implant surgery. Children already up to date with Hib vaccination do not need extra shots before surgery. All preteens and teens should receive a MenACWY vaccine according to the  Preteen/Teen Immunization Schedule . Teens may also receive a MenB vaccine. A MenABCWY vaccine is an option only when a preteen or teen is getting MenACWY and MenB vaccines at the same visit.

43. Many bacteria can cause meningitis The  leading causes of bacterial meningitis  in the United States include: Haemophilus influenzae Neisseria meningitidis  (causes meningococcal meningitis) Streptococcus pneumoniae  (causes pneumococcal meningitis)

44. 2023 CDC Guidelines Adult guidelines for pneumococcal vaccination for cochlear implant patients Adults ages 19-64:  Give one dose of Prevnar 20 (PCV20), then vaccines are complete. If Pneumovax 23 (PPSV23) was used, give one dose of PCV20 one year later, then vaccines are complete. If PCV13 was used, give one dose of PCV20 one year later, then vaccines are complete. This applies to those who only got Prevnar 7: give one dose of PCV20, then vaccines are complete. Adults 65 and up:  Those who never received any pneumococcal vaccines, get one dose of PCV20, then vaccines are complete. For those who only got Prevnar 13, give one dose of PCV20 or PPSV23, and their vaccines will be complete. Give one year after Prevnar 13. If they only got PPSV23, give one dose of PCV20 one year after the dose of PPSV23, then their vaccines are complete. If they got PCV13 at any age and PPSV23 before age 65, give PCV20 five years after the last pneumococcal vaccine, then their vaccines are complete. Pneumococcal guidelines for pediatric cochlear implant surgery patients Ages 2 and younger:  The full vaccine series will soon transition from Prevnar 13 (PCV13) or PCV15 to Prevnar 20 (PCV20). PCV20 to be given at ages 2 months, 4 months, 6 months, and 12 months to 15 months. Once these four are given, vaccines are complete. Ages 2 to 5 years, to catch up:  If PCV13 was given in three doses prior to 12 months old, give one dose of PCV20 eight weeks after the last pneumococcal vaccine. If less than three doses of PCV13 was given before age 24 months, give two doses of PCV20 eight weeks apart, then they are complete. If Pneumovax 23 (PPSV23) was given after age 24 months, their vaccines are complete. If no PPSV23 was given, give one dose of PCV20 or PPSV23 eight weeks after last PCV13, then their vaccines are complete. Ages 2 to 5 years:  If no vaccines at all, give PCV20 in two doses eight weeks apart, then their vaccines are complete. Ages 6 through 18 years:  If they received PCV13 or PCV15 before age 6 but never received PCV20, give PCV20 in one dose if no PPSV23 used. Their vaccines will then be complete. If they had PPSV23, their vaccines are complete.

45. Surgical Implantation

46. Incision The well Mastoidectomy and facial recess Cochleostomy Insertion of electrode array Fixation Device activation Auditory rehabilitation after cochlear implant Auditory training in children after cochlear implant

47. summary Surgery: 3 to 5 hours 1 to 2 day hospital stay 3 to 4 weeks later - switch on

48. INCISION C-shaped Inverted J-shaped The most widely used surgical approach for cochlear implantation is through the facial recess or posterior tympanotomy. Skin incisions are designed to provide coverage of the external portion of the implant package while preserving the blood supply of the postauricular flap. Anterior- or inferior-based flaps are in common usage.

49. The inferior extent of the incision is made well posterior to the mastoid tip to preserve branches of the postauricular artery From here the incision is directed posterosuperiorly and then directed directly superior without a superior anterior limb. In children, the incision incorporates the temporalis muscle to give added thickness.

50. Well anterior to the skin incision, the periosteum is incised from superior to inferior and a posterior periosteal flap is developed. Pocket of periosteal flap is created for positioning the implant induction coil. At the completion of the procedure, the posterior periosteal flap is sutured to the skin flap, compartmentalizing the induction coil from the skin incision.

51. Following the development of the skin incision, a complete mastoidectomy is performed. The horizontal semicircular canal is identified, and the short process of the incus is identified in the fossa incudis. The facial recess is exposed using the fossa incudis as an initial landmark.

52. Recess Marking Template The Recess Marking Template is used to determine the location of the recess bed and channel for the electrode lead. From Advanced Bionics Overhangs maintained- don’t saurerize

53. The facial recess is a triangular area bounded by (1) the fossa incudis superiorly, (2) the chorda tympani nerve laterally and anteriorly, and (3) the facial nerve medially and posteriorly. The facial nerve can usually be visualized through bone without exposing it completely. The round window niche is visualized through the facial recess approximately 2 mm inferior to the stapes.

54. Occasionally, the round window niche is posteriorly positioned and is not well visualized Do not be misdirected by hypotympanic air cells. Entry into the scale tympani of the cochlea is best accomplished through a cochleostomy created anterior and inferior to the annulus of the round window membrane. A small fenestra (usually 0.5 mm) is developed. A small diamond burr is used to "blue line" the endosteum of the scala tympani, and the endosteal membrane is removed with small picks.

55. Electrode Insertion The insertion tool is used to insert the electrode array in the usual fashion. The Insertion Tube is placed just inside the cochlea toward the basal turn of the scala tympani, with the insertion tube slot directed toward the modiolar (or inner) wall. From Advanced Bionics ROUND-WINDOW COCHLEOSTOMY EXTENDED ROUND-WINDOW

56. Electrode Array Placement Within the Cochlea Illustration courtesy of Cochlear Corporation

57. Once electrodes are placed into cochleostomy and extracochlear electrode lead is placed under temporalis muscle, closure of periosteal tissue can begin. After insertion of the active electrode array, the round window area is sealed with small pieces of fascia.

58. A water-tight periosteal closure is performed, and skin closure begins with a subcutaneous absorbable suture

59. NRT Neural response telemetry (NRT) is a method of capturing the action potential of the distal portion of the auditory nerve in cochlear implant (CI) users, using the CI itself to elicit and record the answers. In addition, it can also measure the recovery function of the auditory nerve (REC), that is, the refractory properties of the nerve.

60. Postoperative imaging after cochlear implantation usually is performed by conventional cochlear view (X-ray) or by multislice computed tomography (MSCT). Conventional cochlear view is routinely used mainly in children due to short investigation time and low radiation dose. POST OPERATIVE IMAGING

61. Conventional cochlear view is routinely used mainly in children due to short investigation time and low radiation dose. This technique only gives projective information on the fact that insertion into the cochlea has been successful, but analysis of exact electrode position with regard to the topography of the cochlea is impossible. MSCT after cochlear implantation allows for three-dimensional imaging;

62. Cochlear abnormalities The most common abnormality encountered is the ossified cochlea most commonly after meningitis, although other pathologies may predispose to ossification, including otosclerosis, chronic otitis media, ototoxicity, autoimmunity, trauma and others. The other exception is the case of the cochlear anomaly or dysplasia, encountered in approximately 1.5 percent of cases.

63. Complications: A. Intraoperative 1 . Intraoperative cannot be placed appropriately. 2. Insertion trauma 3. Gusher

64. Complications (cont.): B. Postoperative 1. Postauricular flap edema, necrosis or separation 2. Facial paralysis 3. Transient vertigo is more likely to occur on a totally nonfunctioning vestibular system. 4. Pain is usually associated with stimulation of Jacobson’s nerve, the tympanic branch of the glossopharyngeal nerve. 5. Facial nerve stimulation 6. Meningitis 7. Device extrusion

65. After the surgery Initial stimulation: 4-6 weeks post surgery Adjustments made regularly based on feedback from patients, parents, therapists and educators Rehabilitation to meet specific patient needs Regular follow-up appointments

66. Mapping

67. Rehabilitation

68. For Adults Weekly adjustments of the MAP and communication therapy for the first month. Treatment focuses auditory training, speech reading, music, telephone use & communication strategies.

69. For children After the initial 3 month period, children are usually seen every 3 months for the first year and every 6 months for the second and third years. Thereafter, they are seen annually.

70. Clinical Results - Adults A substantial percentage of postlingually deaf adults demonstrate some open-set speech recognition (that is, understanding words or sentences without a multiple-choice answer format and without lipreading) with a multichannel cochlear implant. Approximately 25% to 50% of the patients with multichannel implants can understand speech to varying degrees on the telephone.

71. With few exceptions, patients demonstrate better perception and recognition of environmental sounds and lip-reading performance with a multichannel cochlear implant.

72. Children An important difference between the performance of adults and children with multichannel implants is the long time course over which learning takes place in the pediatric population. Two other findings with children also are noteworthy. First, improvement in speech perception skills may not be obvious until the devices have been used for 1 year or more. Second, children with the multichannel implant achieve significantly higher scores on nearly every type of speech perception test than do children who use a single-channel cochlear implant.

73. Speech production skills Although the primary role of a cochlear implant is that of an aid to speech perception, a secondary and vital role is that of an aid to speech production. A longitudinal study of speech development in children with implants suggests that these children acquired consonant and vowel features that are difficult for children with profound hearing losses to produce (that is, high vowels, diphthongs, alveolar consonants, and fricatives)

74. Rather the child and family should be counseled carefully regarding realistic expectations in performance with the implant. Earlier the age better the perfomance

75. Physician's role in counseling families regarding cochlear implants Three important areas to be covered with families are benefits, limitations, and risks of the cochlear implant; realistic expectations for a given patient; long-term prospects for the implant, including device failure and device upgrade. In addition to mentioning possible surgical complications, patients should be made aware that any residual hearing in the ear to be implanted will most likely be destroyed as a result of electrode insertion, thereby prohibiting future use of a hearing aid in that ear.

76. Long-term prospects for implant Patients should be counseled regarding the long-term maintenance of the implant, including the cost of parts and repairs and the possibility of device failure that could necessitate additional surgery. Families frequently inquire about the potential for upgrading the device to make use of future improvements in electrode design or speech processing schemes.

77. Despite the fact that the transmastoid facial recess approach continues to be the gold standard and most commonly utilized worldwide for cochlear implant (CI) surgery , a number of other techniques have been developed and described in the literature. While many of these alternative techniques are employed when anatomical constraints require non-traditional approaches, others are used depending on the preference, comfort level, and specific training of the surgeon.

78. VERIA TECHNIQUE MIDDLE CRANIAL FOSSA APPROACH BILATERAL IMPLANT ELECTOACOUSTIC STIMULATION SOFT SURGERY

79. Veria technique

80. suprameatal approach The SMA for performing CI surgery was originally developed by Kronenberg in 1999 based on a blind atticotomy approach, similar to what was once considered an acceptable approach to cholesteatoma.9, 10 A retroauricular skin flap is raised and a subperiosteal flap created to drill a seat in the temporoparietal bone for the receiver-stimulator. Through the postauricular incision, a tympanomeatal flap is created. Once the chorda tympani nerve is identified, a 1-mm groove is drilled in the scutum Middle fossa approach The middle cranial fossa (MCF) approach for cochlear implantation was described in 1908 by Chouard using multiple independent electrodes inserted through multiple labyrinthotomy sites. However, it was not until recently that Colletti et al 12  described the modernized MCF approach to CI surgery for patients with a number of indications, including: chronic ear disease, patients with poor promontory stimulation results, to increase spatial selectivity and improve outcomes via dual electrode array Transcanal wall (“ Veria ”) technique The Veria technique is a nonmastoidectomy technique for cochlear implantation using the transcanal approach to the middle ear and the cochlea. 14  Briefly, the steps of the operation are as follows: (1) endaural or retroauricular approach to the middle ear with elevation of a standard tympanomeatal flap, (2) inspection of the middle ear anatomy (cochlea, fallopian canal, round window niche), (3) straightening of the posterosuperior bony canal wall, (4) cochleostomy, (5) drilling the suprameatal Pericanal electrode insertion technique PEIT is another alternative surgical technique for cochlear implantation that allows electrode insertion without performing a mastoidectomy. 16  In this procedure, the electrode is placed directly through the EAC into the tympanic cavity. Briefly, a standard retroauricular incision is made and the skin in the posterior EAC is lifted until the annulus of the TM is reached. The TM is retracted anteriorly exposing the middle ear and its contents. A standard cochleostomy is performed slightly Transmastoid labyrinthotomy approach Approximately 20% of all children with congenital sensorineural hearing loss have malformations of the inner ear, and the degree of hearing loss associated with many of these anomalies is severe enough to make them candidates for cochlear implantation. In a study by Jackler et al, 23  the common cavity malformation was the second most common cochlear malformation, and these patients can benefit from implantation. 24  Patients with common cavity malformations typically have a thin or absent Keyhole CI The “Keyhole” CI surgery described by Black uses a 15- to 18-mm-diameter C-shape incision on the rear of the auricle with minimal mastoid cell clearance during the facial recess approach.25 Other groups have reported in vitro percutaneous cochlear access using preoperative surgical planning via image-guided navigation.

81. Middle cranial fossa approach Open cavities and profound hearing loss Comparable to traditional routes Avoid meningitis from me infection Also avoid electrode pemetrating IAC Technically challenging, facial nerve damage high May need reverse insertion of implant from apex to base, so programing also is reversed

82. Bilateral implant Bilateral hearing aid improves auditory performance always Binaural advantage mainly from head shadow effect {6db} {speech and noise spatially separated such that one ear is protected from noise by HSE} BETTER SIGNAL TO NOISE RATIO BINAURAL SUMMATION AND SQUELCH EFFECT ARE NEUROPHYSIOLOGIC PROCESS OF CNS and may improve signal to noise ratio improve by 3 dB {conversation in class, crowd, restaurant} Sound localization also improved Single cochlear implant – 56-67 degree, bilateral – 24-29 degrree

83. Electroacoustic stimualtion

84. SOFT SURGERY Deferring the cochleostomy until immediately before electrode insertion Use of a large burr to flatten the promontory, Followed by a smaller burr to expose the endosteum, preservation of the endosteum of the scala tympani, smoothing of the bony edges with burrs and dissectors Limited opening of the scala tympani No suctioning of perilymph Gentle electrode insertion Haemostasis before cochleostomy Potential use of a lubricant to facilitate insertion a 1.6 mm diamond burr to make an excavation down to the white endosteum, followed by a 1 mm diamond burr to create an opening in the bone that is approximately 1.2 to 1.4 mm in diameter Soft surgery is elegant, contains many useful techniques, and is particularly well suited to the Nucleus device, with its thin. flexible electrode. There is, however, no evidence that this technique is associated with improved patient performance, even in patients with some residual hearing. The topic should be pursued further and studies undertaken to evaluate the effects, if any, of atranmatic cochleostomy, use of lubricants, and both relatively shallow and deep electrode insertion.

85. Researchers have focused on reducing costs by adopting semiconductor fabrication processes to reduce manual fabrication costs and to meet the minimum specifications. They used liquid crystal polymer (LCP), a biocompatible, chemically inert, flexible, and thermoplastic material, as a substrate and insulation layer. The LCP-based cochlear electrode arrays include 16 gold contacts and lead wires patterned by photo-lithography and a chemical etching process. The most attractive aspect of the LCP-based cochlear electrode array is its thermoplastic bonding between the substrate and insulation layer. This property facilitates the production of a seamless and MR-compatible LCP-based implantable near-hermetic package as well as an electrode array