Cochlear Implantation at King Abdullaziz University Hospital, Riyadh: A Multisystem Prgram, (1995-2007)

Introduction

The KAUH Cochlear Implant Program started 1995. To date,96 cases have been implanted. Among those, 79 Nucleus, 11 Med-El and 6 Advanced bionics. All are long multi channel cochlear implants.

Candidates Selection

All the patients included in the program had bilateral profound hearing loss with monosyllabic word score of no more than 10% in best aided condition. Their general health was good. They were psychologically stable, with realistic expectation and they are willing to participate in post operative testing and rehabilitation.

Candidates Selection

Radiologic examination (CT,±MRI ) revealed patent cochlea and intact cochlear nerve in all cases. There were no outer or middle ear pathologies that may interfere with surgery.

Candidates selection

Out of all, there were 3 patients with CSOM.

During surgery there were (11) cases with different degrees of ? cochlear ossifications,? rotated cochleae, which were not discovered radiologically.

Evaluation Procedure

Evaluation Intervals: Preoperative evaluation with hearing aids and postoperative evaluation following initial stimulation with cochlear implant, then 3, 6 and 12 months postoperativly.

Hearing thresholds

Sound field warble tone thresholds for frequencies ranging from 250 Hz t0 8000 Hz were measured pre- and post- operatively, with the hearing aid and cochlear implant.

Speech perception tests

Evaluations were done in a calibrated free field, sound treated booth with the subject using their hearing aids before surgery at 70 – 80 dB SPL via a loudspeaker. Evaluations were done in monaural or binaural listening conditions before surgery. After surgery, monaural implant evaluations were performed.

Speech evaluation for children

Preoperative and postoperative evaluation include:

Lip-reading test. Listening Progress Profile. Receptive Language Skill test. Expressive Language Skill test.

Speech evaluation for adults

Minimal Auditory Capability test. (MAC )

Surgical Principles

Incision: Extended endaural(67cases) Minimal invasive ( 29cases )

Skin Incision

1 cm

3-4 cm

Pericranial Flap

1 cm

OriginalIncisionLine

1 cm

Surgery

Surgical Procedure

Surgical Procedure

Surgical Procedure

Results

A total number of 96 patients who met the criteria for implantation were implanted.

These were divided into 4 groups according to the type of implant used.

Summary of implanted groups

GroupCasesElectrodeChannelsSpeech strategyPeriod

Nucleus-22

14 Long

17mm22 SPEAK,CIS 1995-

1999

Nucleus-24

65 Long22mm

22 SPEAK,CIS& ACE

1998-2007

Med-El11 Long

31mm12 CIS& NofM 1999-

2003

Advanced bionics

6 Long 23mm

16 SAS& CIS2005-2007

Demographic findings in different groups

Group 1Group 2Group 3 Group 4

ImplantNucleus-22 Nucleus 24 Med-El Advanced bionics

Number 14 65 11 6

Age: childrenadult

0

14

50

15

7

4

4

2

Sex: malefemale

10

4

40

25

7

4

2

4

Speech: Pre.

Post.

O

14

50

15

7

4

4

2

Side: RtLt

5

9

21

44

3

8

3

3

Complications& follow upExplanted (1)

Thick skin (1)

Dizziness (1)

Gush (1)

Explanted (1)Dizziness (3)

Facial (1)Infection(3)

Ossification(7)Gush (2)

Reimplanted(2)

Explanted (1)Dizziness (1)

Ossification(1)

Tilted cochlea(2) ?ossification

Results

Among the 96 implanted patients there were 33 post-lingual and 63 pre-lingual cases.

The mean age of pre-lingual patients was 3 years & 6 months.

33; 34%

63; 66%

; 0%; 0%

Results

Out of 96 implanted cases we met 11 cases with different degrees of cochlear ossifications. All were implanted either partially or through scala vestibuli.

85

11

010

203040

506070

8090

NormalCochlea

OssifiedCochlea

Results

We met the following conditions either intra, or post-operative.

1 case of facial paralysis.(recovered in 3 months )

3 cases of lymphatic leak. 6 cases of incomplete

insertion(2-5 electrodes out).

3 cases of wound infection. 1 case of thick skin over the

implant 5 cases of post operative

dizziness for few days. 3 explanted cases. 2 reimplanted cases.

61

11 6 1 3 3 1 5 3 20

10

20

30

40

50

60

70Reimplantation(2)

Explantation(3)

Dizziness(5)

Thick skin(1)

Wound infection(3)

Leak(3)

Facial paralysis(1)

Partial insertion(6)

Ossification(11)

Normal(61)

Results

65%11%

6%1%3%

3%1%5%3%2% Normal(61)

Ossification(11)

Partial insertion(6)

Facial(1)

Leak(3)

Wound infection(3)

Thick skin(1)

Dizziness(5)

Explantation(3)

Reimplantation(2)

3 Explanted cases

Tow of them explanted after recurrent otitis media, ear discharge and device failure.

The third explanted after unexplained sever headache and tinnitus.

2 Reimplanted cases

Tow cases were reimplanted after incomplete insertion and torsion of the electrode.

No response was found. They performed well after

reimplantation.

Audiological Results

Pure-tone audiograms, measured before surgery and 6 months after surgery, showed improvement of free field tone threshold for all subjects in our program. The average gain in hearing was 40 dB. No statistical difference was found between groups of implants.

Audiological Results

Comparison between mean pure tone average at different frequencies before implantation and after getting stable map.

Frequency in Hz

500 Hz

1000 Hz

2000 Hz

4000 Hz

8000 Hz

Before

70dB90dB95dB100dB100dB

After35dB40dB40dB45dB40dB

Mean Pure Tone average before & after implantation

70

9095

100 100

3540 40

4540

0102030405060708090

100110

500Hz 1000Hz 2000Hz 4000Hz 8000Hz

Before

After

Listening progress profile

In a prospective longitudinal study of 21 pre-lingual children with age range from 3 to 7 years, a rapid marked improvement in the detection of sound and speech was evident at 6 months post implantation. At 36 months post implantation they reached the maximum score available in our test (LIP test).

Difficulties Faced

Program support and sponsorship. Follow up cases outside Riyadh. Varient family expectation and

support. Implanted cases outside our

program that asking for support.