Policy and procedures for Bone Conduction Implantable Devices Pilot Program

Description

Bone conduction implantable devices are used in cases of conductive hearing loss, mixed hearing loss and single sided deafness, when conventional hearing aids do not provide sufficient access to sound or are contraindicated due to anatomical or chronic middle ear conditions. Information generated through the bone conduction implantable devices enables the recipients to access sound across the speech spectrum at levels required for audition of soft speech sounds.

Bone conduction implantable devices traditionally used a percutaneous titanium abutment, which through osseointegration technology enables vibration created through an externally worn transducer to conduct information through the bone to the cochlea. Transcutaneous devices are available that are implanted and magnetically coupled to the sound transducer worn externally.

The scheduling and procedures of post-operative management of the recipients is determined by the device they receive. Osseointegration occurs over a period of 2- 12 weeks, depending on recipient age, bone quality and device choice, therefore fitting of the external components should be at the direction of the surgeon. In some cases there is a two-stage procedure in finalising osseointegration due to soft, irradiated or thin bone (<3mm) or where the implantation is combined with another surgery, such as tumour removal. Transcutaneous devices can have external components fitted within 2-4 weeks after surgery, even earlier in some cases.

Table 1. Devices available include:

System / Oticon medical / Cochlear Baha® Connect / Cochlear Baha® Attract / Sophono / MedEl Bone-bridge
Type / Percutaneous / Percutaneous / Transcutaneous / Transcutaneous / Transcutaneous
Processor / Ponto
Ponto Pro
Ponto Pro power / Baha 5
Baha BP110 Power
Baha 5 SuperPower / Baha 5
Baha BP110 Power
Baha 5 Super Power / Alpha 2 / Samba
Bone conduction requirements at 0.5,1,2,3 kHz
(not SSD cases) / 0-55dB / 0-65dB / 0-55dB / 0-45dB / 0-45dB
Osseo-integration / yes / yes / yes / no / no
Device fitting
(time after surgery) / 4-12 weeks * / 2-4 weeks* / 4 weeks * / 4 weeks / 2 weeks
MRI compatibility / yes / Yes to 3.0 Tesla / Yes to 1.5 Tesla (magnet insitu) to 3.0 Tesla (magnet removed) / Yes to 3.0 Tesla / Yes to 1.5 Tesla

*Device fitting guide based on healthy adult bone and normal wound healing. Surgeon may recommend longer time to fitting for individual patient criteria based on recipient age, bone quality and device choice.

Referral

Potential recipients of bone conduction implantable devices can be referred by GP’s, ENT’s, audiologists or other hearing health professionals.

Completion of the Preoperative Evaluation and completion of the Clinical Results Form at the time of referral is needed to facilitate consideration of allocation of funding.

Referrals should be made to the Medical Director SCIC Cochlear Implant Program.

Preoperative Evaluation

(Clinical results form completed)

A battery of audiological procedures include:

  • Otoscopy
  • Tympanometry
  • Pure tone audiogram for individual ears with bone conduction and masking where required
  • Speech perception using recorded materials in individual ears, performance on single syllable words, no better than 60% in the poorer ear
  • Speech perception sentences in quiet
  • Speech perception in noise using recorded materials presented at 1 metre at 50dB HL (65dB SPL)
  • Noise configuration to be specified as either S0:N0 – speech and noise both at 180°;Speech 270° Noise 90° with noise facing the better ear)
  • Speech Spatial Quality Scale v5
  • Categories of Auditory Perception 9 (CAP 9)
  • Soft band trial
  • CROS aid trial for SSD patients

Selection criteria

/ Conductive Hearing Loss
Audiometry indicating an air-bone gap of more than 30dB (however may be smaller in cases where air conduction aids cannot be worn or exacerbate other medical conditions.
Bone conduction thresholds up to 65dB (see Table 1)
Tympanometry may be consistent with a conductive component (eg Type B or C tympanogram. However in some permanent conductive conditions, Type A tympanogram may be evident.
Evidence of benefit with preoperative device trial compared to existing condition (ie unaided AC aid)
SSQ no better than an average of 7 on at least one of the scales presented.
/ Mixed Hearing Loss
Audiometry indicating an air bone gap of 30dB (however may be smaller in some cases where air conduction aids cannot be worn or exacerbate other medical conditions).
Bone conduction thresholds up 55 dB (see table 1)
Tympanometry consistent with a conductive component (eg Type B or C tympanogram).
However in some permanent conductive conditions, Type A tympanogram may be evident.
Evidence of benefit with preoperative device trial compared to existing condition (eg unaided AC aid).
SSQ no better than an average of 7 on at least one of the scales presented.
/ Single Sided Deafness (SSD)
Audiometry: Normal hearing to mild hearing loss in the good ear.
Tympanometry: Type A, B or C.SSQ no better than an average of 7 on at least one of the scales presented.
Cros/BiCros trial.
Cochlear implant option discussed.
Realistic expectations needed.
Transcranial attenuation: presence of great attenuation may impact on BCID ability to provide sufficient gain overall or at a particular frequency area.

Contraindications for a bone conduction implantable device

  • Individuals who fall out of the selection criteria indicated above
  • Presence of bone disease that renders the skull too thin to support implant (eg osteogenesis imperfecta)
  • Conditions that may prevent the recipient from adequately maintaining their bone conduction implantable device eg psychological conditions
  • Suitability for surgery /anaesthetic

Prioritisation of candidates for surgery

Priority 1 (high)
Highest priority for first ear for candidates with bilateral maximum conductive losses/ mixed losses who are unable to wear conventional aids and/or are not considered good candidates for surgical/medical intervention for the cause of hearing loss.
Also included in this group are candidates with conductive / mixed loss in their only hearing ear even if conventional aiding is possible.
Priority 2 (mid)
Second highest priority for first ear for candidates with bilateral conductive / mixed losses who demonstrate improved performance with Baha over conventional aiding but don't fall into category 1.
Priority 3 (low)
Third priority category for the following indications:
- second ear on candidates that fall into category 1 or 2
- unilateral conductive / mixed loss candidates
- single sided deafness

Allocation of BCID – consents and agreements

The allocation of the BCID is under a NSW Health program that requires careful evaluation and measurement of outcomes and commitment to attend scheduled appointments. Consents and agreements need to be finalised prior to surgery.

Clients who are eligible for Australian Hearing funding of external components will be considered for BCID surgery through this pilot scheme.

Surgery

Surgery for percutaneous devices may be one step where implant and abutment or magnet is placed; or two step for clients who have thin bone. Two step procedures require a 3-6 month interval for osseointegration to occur before fitting of the abutment.

Device activation and follow up

Device activation should only occur after a medical review from surgeon

Each session should involve a close check of the abutment (where appropriate) or magnet site to detect for skin/tissue complications and ensure no debris is present (which can reduce sound level and quality)

Session 1:Device is programmed and activated for the first time

  • Client is counselled on external components
  • Aided audiogram
  • Phoneme detection to check access to speech spectrum

Session 2: (4 weeks later – 2 weeks for Baha attract recipients):

  • Device program refined
  • Review of magnet selection and strength (Bonebridge and Baha Attract)
  • Client is further counselled on external components & accessories
  • Aided audiogram
  • Phoneme detection and word test speech perception

Session 3:(12 weeks post device activation)

(Clinical results form completed)

  • Evaluation of device and management Device review
  • Review of implant site
  • Otoscopy
  • Tympanometry
  • Pure tone audiogram for individual ears with bone conduction and masking where required
  • Speech perception using recorded materials for single syllable words,
  • Speech perception sentences in quiet
  • Speech perception in noise using recorded materials presented at 1 metre at 50dB HL (65dB SPL). Noise configuration to be specified as either S0:N0 – speech and noise both at 180°;Speech 270° Noise 90° with noise facing the better ear). Noise level to be specified as +10dB SNR; +5dB SNR or 0dB SNR
  • Functional listening questionnaires including the Speech Spatial Quality Scale C v5
  • Categories of Auditory Perception 9 (CAP 9 )

Session 4:(6 months post device activation)

(Clinical results form completed)

  • Device program and review
  • Review of device site
  • Otoscopy
  • Tympanometry
  • Pure tone audiogram for individual ears with bone conduction and masking where required
  • Speech perception individual ears, performance on single syllable words
  • Speech perception sentences in quiet
  • Speech perception in noise using recorded materials presented at 1 metre at 50dB HL (65dB SPL). Noise configuration to be specified as either S0:N0 – speech and noise both at 180°;Speech 270° Noise 90° with noise facing the better ear). Noise level to be specified as +10dB SNR; +5dB SNR or 0dB SNR
  • Functional listening questionnaires including the Speech Spatial Quality Scale C v5
  • Categories of Auditory Perception 9 (CAP 9)

Ongoing management

Recipients will attend regular review appointments as indicated. Reviews are required to verify device integrity through direct check of equipment and performance based procedures.

Earlier appointment times should be scheduled if recipients have any concerns

Review appointments will include:

  • Check device site
  • Check device program
  • Unaided audiogram
  • Aided audiogram
  • Tympanometry
  • Speech perception testing (words and sentences in quiet and in noise)

Functional evaluation (SSQ)

Expected outcomes

Conductive hearing loss
Studies suggest that recipients with an air bone gap of greater than 30dB will experience significant benefit from the Baha compared to air conduction hearing aids.

Mixed losses

Those with mild to moderate sensorineural component. Most powerful Bone conduction implantable device processor can compensate for a sensorineural element of up to 65dB HL (measured at 0.5, 1, 2, & 3 kHz) on a percutaneous abutment.

SSD

Those with normal to mild hearing loss in their good ear can benefit. Limited or no benefit if greater hearing loss. Benefits over a CROS aid include no occlusion of the hearing ear, and no need to wear hearing devices on both ears. Bone conduction implantable device recipients reported quality of life improvements and improvements in difficult listening situations such as conversation in background noise. Bone conduction implantable device cannot provide localisation improvements. (Flynn & Sammeth, et.al., 2010)

References

NHSCB/DO9/P/a

Cochlear Baha systems guide

Flynn MC, Sammeth CA, Sadeghi A, Halvarsson G (2010) “Baha for single sided sensorineural deafness: Review and recent technology innovations” Seminars in Hearing 31 4 326-349

MSAC draft protocol Jan 2015

Appendix
Clinical Reference Forms