Our findings show that there is variability in the clinical and surgical practices of otolaryngologists who perform pediatric BAHA surgeries in Canada. This is consistent with the divergence in practice that is reported in literature. There is inconsistency among respondents with regards to using unilateral hearing loss and trisomy 21 as indications for BAHA implantation. The practice of bilateral BAHA implantation as well as the minimum acceptable age for implantation also varies. Finally, there is significant regional variation in funding for the BAHA surgery, implant, and processor.
Overall, the least commonly reported indication for BAHA implantation was unilateral hearing loss. The utility of BAHAs in these patients is mainly to establish binaural hearing[11, 12]. The reported audiological benefits, however, have been variable in this particular situation, especially in the pediatric population[11, 13–15]. In their study of children and adolescents with unilateral hearing loss, Priwin et al. did not find any improvements in hearing thresholds or sound localization with the BAHA. They did, however, note an improvement in speech recognition, especially in noisy environments. This correlates with other studies in which participants have reported using the BAHA mainly in classrooms. Despite the inconsistencies in reported audiological benefits, BAHAs in children with unilateral hearing loss have been found to have a positive impact on quality of life with high rates of user compliance[14–16]. This may suggest that children experience a subjective benefit even if audiological measurements do not always correspond. Twenty-five percent of our respondents listed unilateral hearing loss as an indication for BAHA implantation, and only 17% routinely offered this treatment to children with congenital unilateral hearing loss. This indicates that the majority has not accepted BAHAs as a beneficial intervention for this cohort of children, which seems appropriate at the current level of evidence.
Trisomy 21 was another uncommon indication according to our respondents (Table 2). Children with trisomy 21 have eustachian tube dysfunction, leading to chronic otitis media with effusion and often, conductive hearing loss. Bone anchored hearing aids have been shown to be beneficial in these children when other methods of re-establishing hearing (ventilation tubes and conventional hearing aids) are unsuccessful[17, 18]. Despite these results, there appears to be a trend of underutilization of BAHAs in some syndromic children. The lower proportion of respondents who use trisomy 21 as an indication for BAHA implantation may be interpreted to be a reflection of this trend. This may be due to a lack of awareness regarding the benefits of BAHAs in children with trisomy 21. Increased awareness and education can therefore be helpful in encouraging otolaryngologists to consider BAHAs as a viable option for hearing restoration in this population in some situations.
The benefits of bilateral BAHA implantation have been debated in the literature. Due to the small attenuation of vibrations in the skull, it has been argued that one BAHA can also stimulate the cochlea on the opposite side[10, 20]. There have been studies, however, which report improved audiological outcomes and quality of life in children fitted with bilateral BAHAs[16, 21, 22], indicating that there may be a role for this intervention in some children. Fifty percent of our respondents have performed bilateral BAHAs in children. Interestingly, most surgeons (83%) who have performed bilateral BAHAs practice in an area where the procedure is partially or fully funded, whereas most of those who have not performed this procedure (67%) work in areas where bilateral BAHAs are not funded. It is possible that in the small population of children who may benefit from this intervention, bilateral BAHAs are underused as a result of funding limitations. A similar trend is expected in many other countries since health care funding is becoming more scarce. As we will discuss later on, there is a need for more comprehensive coverage for the BAHA procedure and related costs. We encourage otolaryngologists who practice in regions with funding limitations to advocate for more adequate coverage, especially in situations where the lack of funding may be the obstacle to an intervention that is known to lead to improved outcomes, such as bilateral BAHA implantation in select cases.
There is no consensus on the ideal age for BAHA implantation in children[6, 9]. Achieving optimal hearing earlier in life best facilitates normal speech and language development[23, 24]. Younger age at the time of intervention, however, is associated with an increased risk of osseointegration failure[3, 9]. This is most likely due to thinner temporal bones as well as the higher water and lower mineral content associated with younger skulls. Other factors that may contribute to failure in younger children include an increased risk of trauma and a decreased ability to care for the implant site[3, 25]. The trend reported in literature is to implant BAHAs in children older than 4 years of age. Others state that children older than 3 years should have adequate bone thickness, and therefore would make suitable BAHA candidates. Our results show that 4 years is the most commonly accepted minimum age for BAHA implantation (42%), followed by 3 years (25%) and 5–6 years (25%). The BAHA softband is routinely fitted for children younger than this for 92% of respondents. Our results imply that there are some children in Canada who are being delayed the BAHA operation secondary to surgeon practices/preferences. By elucidating the fact that the majority of surgeons are successfully performing this procedure in children at age 3–4 years, perhaps those waiting until age 5–6 years would consider implanting the BAHA at an earlier age. This is important since the BAHA processor with implanted abutment has been shown to yield better audiologic results compared to the BAHA headband alone. Therefore, children would benefit from earlier implantation as soon as they are physiologically/anatomically ready to receive the implant.
Similar to how age and bone thickness dictate the timing of the BAHA surgery, these factors were also reported to determine the details of the procedure. Half of the respondents stated that young age and thin temporal bone are indications for two-staged procedure. Few (17%) only considered bone thickness and another 17% only considered age. This is consistent with the literature, where surgeons have reported age and bone thickness to be the major determinants in deciding between a one- or two-staged operation[3, 13, 25]. Some have reported performing two-staged procedure in children with less than 2.5 mm of bone thickness. Similarly, there is support for one-staged procedure in older children whose bone thickness would allow for the implantation of a 4 mm fixture.
One of the most striking results seen in our survey is the variability in the availability and extent of funding for the BAHA surgery, implant, and processor. In some cases, this inconsistency in funding was found to exist even within the same province. Furthermore, there was a lack of reliable funding for post-operative care (e.g., for replacement BAHA sound processors). Others in the past have also recognized the need for more comprehensive funding programs in Canada. Interestingly, one of the challenges encountered is that the BAHA is often considered to be a surgical procedure and not a hearing aid. This distinction can be important since some private health insurance companies provide coverage for hearing aids but not for surgical procedures (or costs related to surgeries). Subsequently, a major challenge identified by parents, which may contribute to a delayed provision of hearing aids, is having to self-fund the costs[27, 28]. We hope that by highlighting this discrepancy and possible inadequacy in funding, we are able to encourage a concerted effort among this small group of practitioners to advocate for more extensive coverage for BAHAs for the indicated cases. Obviously, the situations can be quite different in countries such as the United States, where the healthcare funding does not come from a single payer. Yet, many developed nations will have similar funding issues as the ones identified in our survey. Also, even places like the United States may soon have to deal with “rationing” health care resources due to rising costs.
The limitation of the present study is evident in the survey format, which implies reporting and recall bias. A detailed chart review of all pediatric BAHA patients may have avoided these biases but it was not practical. Also, the low sample size can be considered a limitation. However, this small sample size reflects the small group of surgeons in Canada who perform this procedure in children. This is in keeping with the overall small number of children that require this operation and the vast geographical spread with concentrated populations at urban settings. As well, several Provinces and Territories do not have enough population to support their own pediatric BAHA program, which is evident in our survey results. Other countries or regions may have similar findings with a small number of surgeons performing pediatric BAHA operations.