Conventional external hearing aids can be generally subdivided into air-conduction hearing aids and bone-conduction hearing aids. Air-conduction hearing aids require the use of ear molds, which may be problematic in patients with chronic middle ear and ear canal infections, atresia of the external canal, or an ear canal that cannot accommodate an ear mold. In these patients, bone-conduction hearing aids may be an alternative. External bone-conduction hearing aids function by transmitting sound waves through the bone to the ossicles of the middle ear. The external devices must be closely applied to the temporal bone, with either a steel spring over the top of the head or with the use of a spring-loaded arm on a pair of spectacles. These devices may be associated with either pressure headaches or soreness. Semi-implantable bone-conduction hearing aids have been investigated as an alternative. Although no longer marketed, the Audiant™ bone conductor was a device approved by the U.S. Food and Drug Administration (FDA) that consisted of an external processor that used transcutaneous inductive electromagnetic energy to cause vibration of an implanted titanium magnet screwed into the temporal bone.

While the bone-anchored hearing aids have generally been used for those with conductive hearing loss, their use has also been investigated in patients with unilateral sensorineural deafness. In these patients, a bone-anchored device located near the deaf ear works as a transcranial contralateral routing of signal (CROS) to transmit sound to the contralateral functional cochlea via bone conduction. This application has been evaluated as an option to the traditional air-conduction CROS hearing aid.

The initially marketed BAHA device (Branemark bone anchored hearing aid, Entific Medical System) is based on the same concept. The labeled indication of the BAHA device is as follows: “BAHA hearing aid for single sided deafness is intended for patients who suffer from unilateral sensorineural deafness.”

The BAHA Divino® device (Entific Medical System) received 510(k) clearance from the FDA in 2004. This device is similar to the BAHA device except that sound processing is digital instead of analog. The listed indications include the following: patients who have a conductive or mixed hearing loss and have certain bone-conduction threshold levels, bilateral fitting for those with moderate to severe bilateral symmetric conductive and/or mixed hearing losses, and those with unilateral sensorineural deafness with normal contralateral hearing.

Note: Cochlear implants, used for the treatment of severe to profound deafness, are addressed in policy No. 7.01.05.

• Congenital or surgically induced malformations (e.g., atresia) of the external ear canal or middle ear;
• Chronic external otitis or otitis media;
• Tumors of the external canal and/or tympanic cavity;
• Dermatitis of the external canal.

When the bone-anchored hearing aid is to be used in those with single-sided sensorineural deafness, a trial should generally first be arranged with a BAHA device on a headband placed on the mastoid of the deaf ear to determine the likely benefit of the BAHA.

The following CPT codes describe semi-implantable bone-conduction hearing aids:

69710: Implantation or replacement of electromagnetic bone conduction hearing device in temporal bone*

69711: Removal or repair of electromagnetic bone conduction hearing device in temporal bone*

*The Audiant bone conductor is a type of electromagnetic bone-conduction hearing device. While this product is no longer actively marketed, patients with existing Audiant devices may require replacement, removal, or repair.

69714: Implantation, osseointegrated implant, temporal bone, with percutaneous attachment to external speech processor/cochlear stimulator; without mastoidectomy**

69715: as above, but with mastoidectomy**

** The above 2 CPT codes describe the BAHA device.

Effective in 2007, there are HCPCS codes specific to this device:

L8690: Auditory osseointegrated device, includes all internal and external components

L8691: Auditory osseointegrated device, external sound processor, replacement

BlueCard/National Account Issues

These devices are referred to as Hearing Aid, Bone Conduction in the FDA approval. The FDA review also indicates that this device has substantially equivalent technology as air-conduction hearing aids with digital sound processing. However, beginning December 2005, the Centers for Medicare and Medicaid Services (CMS) began to consider these devices as prosthetics. Thus, plans need to review contract language in making decisions about classification.

Benefit limitations regarding hearing aids may apply to these devices. Many medical insurance plans do not provide coverage for hearing aids or provide limited coverage.

Audiologic criteria for bone-anchored devices in those with a conductive or mixed hearing loss include a speech discrimination score of at least 60% in the affected ear and an average bone-conduction threshold up to 70 dB in the affected ear. The bone-conduction threshold may vary with the device used, for less powerful devices the threshold might not exceed 45 dB.

State or federal mandates (e.g., FEP) may dictate that all devices approved by the U.S. Food and Drug Administration (FDA) may not be considered investigational. However, this policy considers specific applications of an FDA-approved device as investigational. Alternatively, FDA-approved devices may be assessed on the basis of their medical necessity.

Hearing results of semi-implantable bone conduction hearing aids may be compared either to 1) external bone conduction hearing aids in patients with atresias who are unable to use external air conduction hearing aids, or to 2) external air conduction hearing aids in patients who are unable to tolerate air conduction hearing aids due to chronic infection. Reported studies have suggested that the BAHA device is associated with improved hearing outcomes compared to external bone conduction hearing aids and equivalent outcomes compared to a conventional air conduction hearing aid. (1-4)

2007 Update

The policy was updated based on a literature search using MEDLINE through May 2007. McLarnon reported outcomes (benefits) for bone-anchored hearing aids by patient subgroups based on 69 of 94 (73%) patients who completed a questionnaire. (5) This study noted the greatest benefit in those with congenital ear disorders. It also showed benefit to restoring stereo hearing to patients with an acquired unilateral hearing loss after acoustic neuroma surgery. House reported on complications from bone-anchored hearing aids. (6) No intraoperative or perioperative complications were noted in 149 patients who received the device between 2001 and 2005. Significant postoperative complications, requiring intervention, occurred in 19 patients (13%). Skin overgrowing the abutment occurred in 11 patients, and implant extrusion occurred in 5 patients.

Baguley and colleagues reviewed the evidence for contralateral bone-anchored hearing aids in adults with acquired unilateral sensorineural hearing loss. (7) None of the 4 controlled trials reviewed showed a significant improvement in auditory localization with the bone-anchored device. However, speech discrimination in noise and subjective measures improved with these devices; for these parameters, the bone-anchored devices resulted in greater improvement than that obtained with the conventional air-conduction CROS systems. The authors of this review did note shortfalls in the studies reviewed. Lin reported on use of the bone-anchored hearing aids in 23 patients with unilateral deafness, and noted that speech recognition in noise was significantly better with the BAHA device than with the air-conduction CROS device. (8) While the report also comments that benefit was seen in those with moderate sensorineural hearing loss in the contralateral ear (25–50 dB), this conclusion was based on 5 patients. Larger studies are needed before changes can be considered in the policy statement regarding use in this clinical situation.

Bilateral devices

Use of bilateral devices has been evaluated in patients with conductive or mixed hearing losses. A number of studies, published over several years, have demonstrated a consistent improvement in speech recognition in noise and in sound localization with bilateral devices. In 2001, Bosman and others reported on findings from 25 patients who were using bilateral devices. (9) They found that both speech recognition in noise and directional hearing improved with the second device. In a 2004 publication, Priwin and colleagues reported similar findings on 12 patients with bilateral devices. (10) A consensus statement published in 2005 concluded that bilateral devices resulted in binaural hearing with improved directional hearing and improved speech-in-noise scores in those with bilateral conductive hearing loss and symmetric bone-conduction thresholds. (11) A number of additional studies that are cited in this report found benefits similar to those noted in the studies of Bosman et al (9) and Priwin and colleagues. (10) Thus, based on these numerous studies, bilateral devices may be considered medically necessary when there is bilateral conductive or mixed hearing loss with symmetric bone-conduction thresholds.

2008 Update
The policy was updated based on a literature search using MEDLINE through August 2008. None of the information identified leads to a change to the policy statements. Two studies of bone-anchored hearing aids for congenital unilateral conductive hearing impairment are reported by Kunst et al. In one study aided and unaided hearing was assessed in 20 patients using sound localization and speech recognition-in-noise tests. (12) Many patients showed unexpectedly good unaided performance, however non-significant improvements were observed in favor of the BAHA. Six of 18 patients with a complete data set did not show any improvement at all, however compliance with BAHA use in this patient group was remarkably high suggesting patient benefit. The same authors evaluated 10 adults and 10 children using 2 disability-specific questionnaires and found an overall preference for the BAHA over unaided hearing in several specific hearing situations. (13) Improvement on the Glasgow children’s benefit inventory was most prominent in the learning domain. The 10 adults showed an already good score on the Speech, Spatial and Qualities of hearing scale in the unaided situation. Tringali et al surveyed patients using a BAHA to compare patient satisfaction by indication: 52 respondents with conductive or mixed hearing loss (CHL) (44 with chronic otitis and 8 with malformation of the middle ear) compared with 118 with single side deafness (SSD) (2 after surgery for meningioma, idiopathic sudden deafness, sensorineural hearing loss complication surgery of the middle ear). (14) Levels of satisfaction and quality of life were significantly poorer in the SSD than in the CHL group though generally good with the exception of sound localization.

The BAHA device has been used successfully in children younger than 5 years in Europe and the United Kingdom. (The most recent (1999) update of the FDA notification lists age less than 5 years as a contraindication.) A number of papers describe experience with preschool children or children with developmental issues that might interfere with maintenance of the device and skin integrity. A 2-stage procedure is used in young children with the fixture placed into the bone at the first stage and, after 3-6 months to allow for osseointegration, a second procedure to connect the abutment through the skin to the fixture. Davids and colleagues at the University of Toronto provided BAHA devices to children less than 5 years of age for auditory and speech-language development and retrospectively compared surgical outcomes for a study group of 20 children 5 years or younger and a control group of 20 older children. (15) Children with cortical bone thickness greater than 4 mm underwent a single-stage procedure. The interstage interval for children having 2-stage procedures was significantly longer in the study group in order to allow implantation in younger patients without increasing surgical or postoperative morbidity. Two traumatic fractures occurred in the study group vs 4 occurred in the older children. Three younger children required skin site revision. All children were wearing their BAHA devices at time of writing. McDermott reported on the role of bone anchored hearing aides in children with Down syndrome in a retrospective case analysis and postal survey of complication rates and quality of life outcomes for 15 children aged 2 to 15 years. (16) All patients are using their BAHA devices after follow-up of 14 months. No fixtures were lost, and skin problems were encountered in 3 patients. All 15 patients had improved social and physical functioning as a result of better hearing.

References:

1. Snik AF, Mylanus EA, Cremers CW. The bone-anchored hearing aid compared with conventional hearing aids. Audiologic results and the patients’ opinions. Otolaryngol Clin North Am 1995; 28(1):73-83.
2. Wazen JJ, Caruso M, Tjellstrom A. Long-term results with titanium bone anchored hearing aid: the U.S. experience. Am J Otol 1998; 19(6):737-41.
3. van der Pouw CT, Snik AF, Cremers CW. The BAHA HC200/300 in comparison with conventional bone conduction hearing aids. Clin Otolaryngol 1999; 24(3):171-6.
4. Granstrom G, Tjellstrom A. The bone-anchored hearing aid (BAHA) in children with auricular malformations. Ear Nose Throat J 1997; 76(4):238-47, passim.
5. McLarnon CM, Davison T, Johnson IJ. Bone-anchored hearing aid: comparison of benefit by patient subgroups. Laryngoscope 2004; 114(5):942-4.
6. House JW, Kutz JW. Bone-anchored hearing aids: incidence and management of postoperative complications. Otol Neurotol 2007; 28(2):213-7.
7. Baguley DM, Bird J, Humphriss RL et al. The evidence base for the application of contralateral bone anchored hearing aids in acquired unilateral sensorineural hearing loss in adults. Clin Otolaryngol 2006; 31(1):6-14.
8. Lin LM, Bowditch S, Anderson MJ et al. Amplification in the rehabilitation of unilateral deafness: speech in noise and directional hearing effects with bone-anchored hearing and contralateral routing of signal amplification. Otol Neurotol 2006; 27(2):172-82.
9. Bosman AJ, Snik AF, vander Pouw CT at al. Audiometric evaluation of bilaterally fitted bone-anchored hearing aids. Audiology 2001; 40:158-67.
10. Priwin C, Stenfelt S, Granstrom G et al. Bilateral bone-anchored hearing aids (BAHAs): an audiometric evaluation. Laryngoscope 2004; 114:77-84.
11. Snik AF, Mylanus EA, Proops DW et al. Consensus statements on the BAHA system: where do we stand at present? Ann Otol Rhinol Laryngol Suppl 2005; 195:2-12.
12. Kunst SJ, Leijendeckers JM, Mylanus EA et al. Bone-anchored hearing aid system application for unilateral congenital conductive hearing impairment: audiometic results. Otol Neurotol 2008; 29(1):2-7.
13. Kunst SJ, Leijendeckers JM, Mylanus EA et al. Subjective benefit after BAHA system application in patients with congenital unilateral conductive hearing impairment. Otol Neurotol 2008; 29(3):353-58.
14. Tringali S, Grayeli AB, Bouccara D et al. A survey of satisfaction and use among patients fitted with a BAHA. Eur Arch Otorhinolaryngol 2008. [Epub ahead of print]
15. Davids T, Gordon KA, Clutton D et al. Bone-anchored hearing aids in infants and children younger than 5 years. Arch Otolaryngol Head Neck Surg 2007; 133(1):51-5.
16. McDermott AL, Williams J, Kuo MJ. The role of bone anchored hearing aids in children with Down syndrome. Int J Pediatr Otorhinolaryngol 2008; 72(6):751-7.

Audiant™ Bone Conductor
Bone Anchored Hearing Aids, Semi-implantable
Hearing Aids, Bone Conduction, Implantable