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Congenital aural atresia: Bone-anchored hearing aid vs. external auditory canal reconstruction
International Journal of Pediatric Otorhinolaryngology 76 (2012) 272–277
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Congenital aural atresia: Bone-anchored hearing aid vs. external auditory canal reconstruction Sarah Bouhabel, Pierre Arcand, Issam Saliba * Sainte-Justine University Hospital Center (CHU SJ), University of Montreal, 3175, Coˆte Sainte-Catherine, Service ORL, Montreal H3T 1C5, Quebec, Canada
A R T I C L E I N F O
A B S T R A C T
Article history: Received 31 October 2011 Received in revised form 20 November 2011 Accepted 21 November 2011 Available online 15 December 2011
Objective: To compare the audiologic outcome and feasibility of bone-anchored hearing aid (BAHA) and external auditory canal reconstruction (EACR) surgeries in pediatric patients presenting a congenital aural atresia (CAA). Methods: A retrospective chart review of 40 patients operated in our tertiary pediatric care center between 2002 and 2010 was performed. 20 patients underwent EACR, whereas another 20 patients were implanted with a BAHA device. Air conduction (AC), bone conduction (BC), pure tone average (PTA) and speech discrimination score (SDS) were compared preoperatively, and hearing gain (HG) postoperatively at 6 and at 12 months at frequencies of 500, 1000, 2000 and 4000 Hz. Operative time, complications and associated microtia were documented as well. EACR patients were graded retrospectively upon Jahrsdoerfer’s classification. Results: Preoperative AC were significantly different between groups, at 500, 1000 and 2000 Hz but not at 4000 Hz. BAHA group compared postoperatively to EACR group showed significantly a superior HG of 46.9 7.0 dB (p < 0.001) and of 39.8(7) 7.2(6.9) dB (p < 0.001) at 6 months and at 1 year, respectively. Moreover, aided air thresholds from the EACR group revealed an audiologic status similar to those of the BAHA group patients, at 6 months and one year postoperatively. Both groups had a similar evolution of their BC, as well as of the incidence of complications. We report one case of transient facial paralysis in the EACR group. Total operative time is significantly lower (p < 0.001) for a BAHA implantation (56 21 min) than for EACR surgery (216 174 min). No preoperative or postoperative correlation (Pearson correlation test; p > 0.05) was found between patient’s Jahrsdoerfer’s score and their audiologic outcome. HG does not seem to be influenced by the presence of microtia. Conclusion: EACR, although constituting an attractive option, does not give acceptable results alone. It can however, when combined to conventional air conduction hearing aids, provide excellent audiologic outcomes comparable to BAHA. BAHA implantation is a reliable, safe and efficient therapeutic option that allows a significantly better audiologic outcome when compared to unaided EACR for patients with CAA. ß 2011 Elsevier Ireland Ltd. All rights reserved.
Keywords: BAHA Bone anchored hearing aid Atresia Microtia Ear canal Canal reconstruction Congenital aural atresia Stenosis
1. Introduction Congenital aural atresia (CAA) is a rare malformation of the external auditory canal (EAC). It results from an abnormal embryologic development of the first branchial arch. Whereas most of the cases are sporadic, it is sometimes associated with syndromes like Treacher Collins or with chromosomical abnormalities like 18q deletions [1]. There is a frequent association with microtia. This entity is encountered in about 1 in 10,000 births,
* Corresponding author at: Department of Otolaryngology, Head & Neck Surgery, CHU Sainte-Justine, 3175, Coˆte Sainte-Catherine, Montreal (Qc) H3T 1C5, Canada. Tel.: +1 514 345 4857; fax: +1 514 737 4822. E-mail address: [email protected] (I. Saliba). 0165-5876/$ – see front matter ß 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2011.11.020
predominantly in males (2.5:1 male to female ratio), and usually occurs unilaterally [2]. In 1883, Kiesselbach performed the first documented attempt of surgical correction for this anomaly [3]. The surgical reconstruction option is indeed a challenging therapeutic option, considering the lack of landmarks and the altered anatomy of facial nerve and middle ear [4]. Moreover, it carries many risks for complications, including iatrogenic injury to the facial nerve, EAC restenosis and recurrent otitis externa [5]. The development of grading and classification systems for EAC atresia such as Jarhrsdoefer’s classification has helped in the preoperative evaluation and outcome expectations [6]. However, the bone conduction concept advanced by Tjellstrom in 1980 brought an interesting alternative to the management of this entity [7]. This led to the bone-anchored hearing aid (BAHA) system that is now
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widely used in developed countries [8]. The BAHA is a surgically implantable system that functions through direct bone conduction rather than via the middle ear. Multiple studies have assessed long-term audiologic results and complications of each of the treatment options. However, none has clearly compared in one series strictly the audiologic outcome of both strategies nor stated the superiority of one option towards the other. Of note that Evans et al. in 2007 indeed studied both strategies, but mostly comparing the complications and costeffectiveness of these therapeutic options [5]. Therefore, the purpose of this study is to determine which option would be, for EAC atresia, the treatment of choice regarding the audiologic gain and feasibility. In order to do that, we examined retrospectively our series with both treatment options by comparing and analysing the initial audiologic status of EAC atresia, the postoperative hearing improvement, the complications and the total operating time. 2. Patients and methods We performed a retrospective review and analysis of the medical records of 40 patients (43 ears) who were treated for their EAC atresia in our pediatric tertiary care center, between 2002 and 2010. These patients underwent either surgical EACR (N = 20), or BAHA implantation (N = 20). The decision-making algorithm used in our institution (Fig. 1) was based primarily on the initial degree of the EAC stenosis. If the stenosis was complete, as visualized on the temporal bone computerized tomography (CT) scan (Fig. 2a), BAHA implantation was preferred. However, if the patient presented a partial stenosis (Fig. 2b), we took into account the degree of the ossicular chain malformation. Strong deformation of the ossicles led to BAHA implantation whereas patients with mild malformations and for whom we could not initially offer a conventional hearing aid were considered as a potential candidates for EACR with or without ossiclar chain reconstruction. These patients could benefit from a conventional hearing aid after the EACR. Discussion with the family also oriented the therapeutic choice. We used 3 mm (N = 6) and 4 mm (N = 14) auto-tarauding fixtures for the BAHA patients group. As for the EACR group, 10 out of 20 patients needed ossicular reconstruction simultaneously to the EACR procedure. Of note that microtia was present for 14 patients in the BAHA group and for 7 patients in our EACR group. Three patients had a bilateral external auditory canal atresia, two of them underwent bilateral EACR and one had bilateral BAHA implantation. We took in consideration only the first operated ear for those patients. Moreover, patients from the EACR group were graded retrospectively upon Jahrsdoerfer’s classification (Table 1) to assess the correlation between the malformation severity score
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and their audiologic outcome. Jahrsdoerfer’s score, is a potential radiologic indicative factor of the degree of malformation. 2.1. Surgical techniques Detailed description of the BAHA and EACR surgery can be found elsewhere [9–12]. A single-stage procedure was performed in all our cases of BAHA implantation. A period of 4 months was allowed for osteointegration before BAHA processor fitting. As for reconstructive surgery, the endaural approach was preferred. 2.2. Main outcome measures Evaluation of the hearing improvement for both treatments was done by comparing the preoperative and the postoperative hearing tests. Hearing thresholds at 500, 1000, 2000 and 4000 Hz frequencies were studied for both groups. Pure tone average (PTA) values was defined as the average of AC thresholds at 500, 1000, 2000 and 4000 Hz. Bone conduction (BC), air conduction (AC), PTA and speech discrimination score (SDS) values were compared. We assessed the hearing improvement of BAHA recipients and EACR patients at 6 months and at one-year follow up. Furthermore, regarding the possibility of EACR patients having had revision surgeries, only the final audiogram results were chosen for comparison. The speech discrimination gain was assessed and compared for each group as well. Total operating time for BAHA and EACR, including revision surgeries, were also gathered. Postoperative and intraoperative complications were recorded for each treatment. For the EACR group, we documented the presence or absence of the following most commonly encountered complications, as mentioned through literature: infection, tympanic membrane lateralisation, bony or soft tissue meatal or canal restenosis, facial nerve paralysis, sensorineural hearing loss (SNHL), skin graft failure, wound dehiscence (<1 cm), postauricular hematoma, scar contracture and hypertrophy, and temporomandibular joint pain and trauma. Intraoperative complications assessed were: dura mater lesions, facial nerve and tympanic membrane injury. For the BAHA group, we assessed the presence or absence of: local infection or inflammation, failure to osteointegrate, skin overgrowth, fixture loss and flap necrosis as the postoperative complications. Whereas for the intraoperative complications in this group we identified the presence of haemorrhage or cerebrospinal fluid leak through the drilling site. 2.3. Statistical analysis Variance analysis was conducted, with repeated measures for the intra-subjects frequency factor, as well as for the inter-subjects
Fig. 1. Decision-making algorithm used in our institution. EACR: external auditory canal reconstruction; BAHA: bone-anchored hearing aid.
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Fig. 2. Axial cuts of computerized tomography scan showing a complete (a) and partial (b) external auditory canal stenosis (arrow). Table 1 External auditory canal reconstruction patients graded upon Jahrsdoerfer’s classification and the number of patient (N) in our series with corresponding scores. Points
Parameter [6]
Scoring
Candidacy
Our series (N)
2 1 1 1 1 1 1 1 1 10
Stapes present Oval window opened Middle ear space Facial nerve Malleus/incus complex Mastoid pneumatised Incus-Stapes connection Round window Appearance external ear Total of points
10 9 8 7 6 5 or less
Excellent Very good Good Fair Marginal Poor
0 2 3 3 2 6
group factor. Analysis were done with SPSS software (version 19), using significance threshold fixed at a = 5%.
3. Results 3.1. Patients Age at surgery ranged from 3 to 18 years old, with a mean of 9.2 years old for patients undergoing EACR and 8.5 years old for BAHA recipients. Patients characteristics are summarized in Table 2. None of the patients was excluded. Of the 3 cholesteatoma cases, 2 were from the EAC, as 1 was from the middle ear. Moreover, one patient in the EACR group appeared to have a positive family history of CAA (Table 2). We were able to attribute Jahrsdoerfer’s score to 16 of the 20 patients of the EACR group (Table 1). CT scan were unavailable for 4 patients.
3.2. Audiologic outcome 3.2.1. Air conduction Preoperative air conductions were significantly different between groups, at 500, 1000 and 2000 Hz but not at 4000 Hz. The patients fitted with a BAHA implant had a worse preoperative audiologic status, compared to the patients undergoing EACR surgery (Table 3). At 6 months postoperatively, the mean hearing gain for the EACR group was 2.0 4.6 dB (confidence interval (CI) 95%:[ 11.6– 7.5]) (Fig. 3), whereas patients fitted with a BAHA demonstrated an average hearing gain of 44.9 5.3 dB (CI 95%: [33.8–55.9]) (Fig. 4). We recorded a mean hearing improvement of 46.9 7.0 dB for the BAHA fitted patients at 6 months when compared to the patients of the EACR group (p < 0.001) at 500, 1000, 2000 and 4000 Hz frequencies (Table 4). At one year after surgery, EACR group had an air conduction improvement of 3.5(6) 4.8(5) dB, CI 95% [ 5.8–13.058] (Fig. 3), whereas patients fitted with a BAHA had a mean hearing gain of 43.3 5.2 dB, CI 95% [32.2–54.3] (Fig. 4). The BAHA group presented a mean hearing gain of 39.8(7) 7.2(6.9) dB when compared to the patients in the EACR group (p < 0.001). The improvement appeared to be the same throughout all the frequencies (500, 1000, 2000 and 4000 Hz) (Table 4). 3.2.2. Bone conduction Preoperative mean bone conduction for BAHA group (8.21 10.89 dB) and for the EACR group (9.51 11.44 dB) were not statistically different (p = 0.691).
Table 2 Patient’s characteristics: BAHA group vs. EACR group. Characteristics
BAHA group N = 20
EACR group N = 20
p-values
Sex (male:female) Age (years) Mean SD (range) Side (left:right) Cholesteatoma Associated microtia Family history of CAA
10:10 8.5 3.5 (3–17)
12:8 9.2 4.1 (3–17)
p = 0.525 p = 0.564
7:13 3 14 0
10:10 1 7 1
p = 3.37 p = 0.292 p = 0.027 (<0.05) –
BAHA: bone-anchored hearing aid; EACR: external auditory canal reconstruction; SD: standard deviation; CAA: congenital aural atresia.
Fig. 3. Evolution of the hearing gain at 6 months and at 1 year follow up for the external auditory canal reconstruction group. dB: decibel; Hz: hertz.
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Table 3 Preoperative air conduction and PTA means in decibel (dB) standard deviation (SD) for BAHA and EACR groups. Frequencies (Hz)
BAHA (mean SD) (dB)
EACR (mean SD) (dB)
Difference (mean SD) (dB)
p-Values
500 1000 2000 4000 PTA
73.8 5.4 66.9 4.6 56.1 4.1 50.8 3.7 61.9 4.5
53.0 5.1 50.0 4.5 43.3 4.8 44.6 3.6 47.8 3.7
20.8 7.4 16.9 6.5 11.8 5.6 6.1 5.3 14.2 5.8
p = 0.006 p = 0.007 p = 0.028 p = 0.183 p = 0.015
BAHA: bone-anchored hearing aid; EACR: external auditory canal reconstruction; SD: standard deviation; Hz: hertz; PTA: pure tone average.
No sensorineural hearing loss was noted postoperatively in the two groups. Mean bone conduction remains stable. 3.2.3. Pure tone average PTA values for the EACR group did not show any evolution over time, varying from a mean of 46.1 dB preoperatively, to 51.7 dB at 6 months follow up and to 38.6 dB at one year (p = 0.224). 3.2.3.1. Speech discrimination score. SDS in the EACR group varied from 90.0 7.3% preoperatively, to 75.3 12.1% at 6 months and to 85.0 8.0% at one year follow up. Whereas in the BAHA group, it varied from 88.8 4.6% preoperatively, to 90.0 4.7% and 91.3 3.1% at 6 months and at 1 year follow up, respectively, with no statistically significant difference (p > 0.05). 3.2.4. Impact of preoperative and postoperative factors on audiologic outcome 3.2.4.1. Degree of atresia. The degree of atresia, whether it was complete or partial, showed no significant impact on the audiologic outcome of the BAHA group (p > 0.05). 3.2.4.2. Presence of microtia. Eventhough the distribution of microtia was significantly different between the two groups (14 patients in the BAHA group and 7 patients in the EACR group) (p = 0.027), the presence of microtia did not appear to have impact on the audiologic outcome on each of the two groups (p = 0.406).
3.2.4.5. Air conduction hearing aids. Moreover, 6 out of the 20 EACR patients felt the need for a complementary hearing aid (air conduction hearing aids – ACHA) during the postoperative course. Aided air thresholds of these patients revealed an audiologic status not statistically different to those of the BAHA group patients, at 6 months and at one year postoperatively (p > 0.05) (Table 5). 3.2.4.6. Operating time. Total operating time is significantly lower (p < 0.001) for a BAHA implantation (56 21 min (CI 95%: [25– 100])) than for a EACR procedure (216 174 min (CI 95%: [90–885])). 3.2.4.7. Revision surgeries. Revision surgeries were necessary for 3 cases of the reconstruction group: 1 case for a meatal restenosis, 1 case for a partial ossicular replacement prosthesis (PORP) revision and 1 case for a stapedectomy revision. 3.2.4.8. Complications. In the EACR group, we report one case of transient facial nerve paralysis, 1 case of meatal restenosis (5%) as well as one case of keloid cicatrisation at skin-graft donor site. For the BAHA implantation group, we report 3 cases (15%) of infection around the abutment 4 (N = 2) and 6 (N = 1) months postoperatively, successfully treated with silver nitrate cauterization and a first generation cephalosporin oral antibiotic. We also report 2 cases (10%) of traumatic fixture extrusion, 2 and 4 weeks postoperatively. Overall, the incidence of complication was not significantly higher in one group towards the other (p = 0.273). 4. Discussion
3.2.4.3. Jahrsdoefer’s score. It was obtained for 16 out of 20 patients of the EACR group. The CT scan of the remaining 4 patients were not available. Audiologic results found no preoperative or postoperative correlation (Pearson correlation test; p > 0.05) between patient’s initial Jahrsdoerfer’s score and their audiologic outcome. 3.2.4.4. Ossicular chain reconstruction. In the EACR group, PTA was not different between patients with or without ossicular chain reconstruction (42.6 dB vs. 39.72 dB; p > 0.05) at 6 months and 1 year after surgery.
Fig. 4. Evolution of the hearing gain at 6 months and at 1 year follow up for BAHA group. dB: decibel; Hz: hertz.
Multiple scoring systems to evaluate the EAC atresia patient’s candidacy for surgical reconstruction surgery have been developed throughout years. Jahrsdoerfer’s classification (Table 1) was cited by many authors throughout literature, and this grading system is based mainly on the evaluation of the preoperative temporal bone CT scan and on the appearance of the external ear [6,13,14]. A predictive audiologic outcome is then determined from the patient’s score. According to this classification, a score of 5 or less disqualified patients as candidates for reconstruction. Consequently, a study conducted by Granstro¨m et al. strongly recommended the implantation of BAHA in patients scoring less than 6 points[13]. Eventhough 6 of our EACR group had a score of 5 or less, we were not able to detect any correlation between the attributed Jahrsdoerfer’s score and the degree of hearing improvement or EAC restenosis in our series. Sex distribution was even in our population (p = 0.525), despite the male predominance reported in the literature[2]. Both groups initially appeared to be similar, except for the microtia distribution. 14 cases of microtia were included in the BAHA group, compared to 7 cases for the EACR group (p = 0.027). This difference in the distribution could not be explained by the decision making algorithm used in our establishment, since it does not take this factor into account. However, Chang et al. reported a poorer audiologic outcome in patients with microtia grade II or III undergoing reconstruction surgery, even if they were initially considered relatively good candidates following Jahrsdoerfer’s classification (<6 points) [6,15]. The risk for restenosis, as well as
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Table 4 Mean hearing gain expressed in decibel (dB) standard deviation (SD) at 6 months and 1 year after surgery. Follow up
BAHA (mean SD) (dB)
6 months 1 year
44.9 5.3 43.3 5.2
EACR (mean SD) (dB) 2.0 4.6 3.5 4.8
Difference between the two groups (mean SD) (dB)
p-Values
46.9 7.0 39.8 7.2
<0.001 <0.001
BAHA: bone-anchored hearing aid; EACR: external auditory canal; dB: decibel; SD: standard deviation; Hz: hertz.
for consequent revision surgery for these patients was higher. Considering the lack of details in the medical charts regarding the degree of microtia, we could not evaluate the effect of this variable on our population. We can however conclude that the over representation of this characteristic in the BAHA group is related to the higher number of total stenosis. However this factor did not have any impact on the hearing gain in this group because we bypass the EAC and the middle ear effect. Patients undergoing EACR, with or without ossicular reconstruction, showed a poor audiologic outcome. Evans et al. obtained a mean hearing gain of 17.7 dB [ 12.5–42.8], Chang et al. reported a mean hearing gain of 20 dB, while Granstro¨m et al. had improvements varying from 0–10 dB for 24 patients, to 10–30 dB for 19 patients and more than 30 dB for 5 patients [5,13,15]. Overall, patients who underwent reconstruction surgery for their congenital aural atresia (CAA) in our cohort did not have a statistically significant hearing improvement. However, they reported a clinical subjective hearing improvement, which was stable over time. Only 30% of our series (6/20) needed a conventional hearing aid during their postoperative course. Their obtained aided thresholds were extremely satisfactory, showing values similar to the postoperative BAHA results, at 6 months and 1 year follow up. Moreover, the obtained values fall within the expected values for aided thresholds for children with conductive hearing loss (15– 20 dB) [16]. Air conduction hearing aid therefore seems to be of a great improvement to the audiologic status of the reconstructed patients. However, 14 patients from the EACR group felt no need for a supplementary hearing aid. The paucity of patients feeling the need for auditory hearing aid is most probably caused by the fact that patients chosen for EACR already had a certain degree of middle ear formation (Fig. 1). The satisfaction in their audiologic status may also be due to the fact that their contralateral ear is normal in most cases. BAHA also seems to constitute a great alternative when EACR fails to provide the expected results. Accordingly, Granstro¨m et al. reported that 16 patients out of 44 were fitted with a BAHA implant after an ossicular chain reconstruction surgery and that all the 16 patients subjectively reported a significant improvement of their hearing capacities [13]. Moreover, Evans et al. reported that 93% of the patients who underwent surgical reconstruction needed a form of amplification postoperatively. None of the patients from our series developed any postoperative sensorineural hearing loss, therefore speech discrimination score did not show any clinical or statistical difference between groups. The fact that the patients fitted with a BAHA had a worse preoperative air conduction when compared to the patients undergoing reconstructive surgery can be explained by the decision-making algorithm used for patient selection. Indeed, Table 5 Mean aided thresholds (dB) for external auditory canal reconstruction and bone anchored hearing aid (BAHA) patients. Frequencies (Hz)
Mean aided threshold (mean SD) (dB)
BAHA at 6 months
BAHA at 1 year
500 1000 2000 4000
23.75 4.79 16.25 13.15 12.50 11.90 21.25 6.29
17.9 10.0 15.8 9.0 16.6 8.3 25.8 13.0
18.3 7.1 17.9 6.9 20.4 8.9 22.1 11.4
dB: decibel; SD: standard deviation; Hz: hertz.
patients with complete stenosis were provided with a BAHA implant. Consequently, EACR patients would not acquire the resonance effect provided by the EAC because of the partial stenosis explaining as well the absence of difference at 4000 Hz [18] with the BAHA group. Patients fitted with a bone-anchored hearing aid benefited from a tremendous hearing improvement much better than patients who underwent EACR. The mean hearing gain obtained 44.9 5.3 dB [CI 95%: (33.8–55.9)] at 6 months and 43.3 5.2 dB [CI 95%: (32.2–54.3)] at one year is similar to the values encountered through the literature [5,17] and appeared to be stable over time as well, considering our one year follow up. The implantation of a bone-anchored hearing aid appears to be a significantly more efficient approach to provide a substantial hearing improvement for patients presenting with CAA. The BAHA implant allows a bone-conducted transmission of sound directly through the cochlea, whereas postoperative EACR is still dependant on the external and middle ear that BAHA implants permit to bypass. The efficiency of the BAHA is therefore in part due to the inherent nature of the device, since it provides predictible results that do not depend solely on the degree of malformation of the middle or external ear [17]. The incidence of complications in our population was compatible with literature complication rates. The 5% occurrence of restenosis in the EACR group is lower than the reported range of 8–29% [19,20] because in our algorithm we perform EACR only for partial EAC atresia. Accordingly, the 10% (2/20) occurrence of fixture loss in the BAHA group appeared to fit within reported limits of 5–29% [21]. However, these few cases were traumatic and happened before the 4th month after implantation and are not cases of implant rejection. Oliver et al. reported in this pediatric series 22 fixture loss out of 71 implantations, and 77% of them were non traumatic [22]. Our fixture loss rate, being mainly traumatic, may therefore be lower than reported rates in the literature. The two-staged BAHA system placement is the standard management described in the literature for BAHA in children. However, single-stage BAHA placement is the standard technique in our pediatric center. It is efficient and safe [4,21]. Single-staged BAHA indeed avoids a second procedure and provides an earlier hearing rehabilitation. Evans et al. reported that single-stage BAHA implantation yields an even greater cost savings at just over one quarter of the cost of surgical EACR [5]. All complications of the single-stage were related to skin reaction. In our series, the 15% occurrence of granulation at the surgical implantation site was higher than reported data (4.5%) [4]. Considering that skin infection may often be self-limited and locally treated by patients or their parents, this complication might be underreported in certain studies. Despite the fact that the strict incidence of complications between groups was not statistically different (p = 0.273), there indeed is a difference regarding their severity. The complications encountered in the EACR group such as meatal restenosis and transient facial nerve injury, require much more care when compared to the surgical site infections or to the fixture loss in the BAHA group. In our series, revision surgeries appear to be more commonly encountered in patients undergoing reconstruction surgery, as reported by Chang et al. (26.6% of their studied population). The most common cause for revision surgery is meatal restenosis
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(58%), followed by conductive hearing loss (20%) and chronic drainage or infection (19%), as stated by Oliver et al. [22]. BAHA implant indeed constitutes a reliable device. Patient satisfaction is extremely good and there is consequently a noteworthy improvement in their quality of life[21]. The procedure is of course less demanding in term of operative time as well, as demonstrated in this study. From a strictly audiologic standpoint, it is obvious that BAHA implantation gives superior results when compared to surgical EACR. However, post operative outcomes of EACR patients supplemented with hearing aids seems to be similar to BAHA group patients outcomes. From a cosmetic standpoint, it is of note that patients from the BAHA group usually let their hair grow more from the side of the implant. With time, the implant is less visible and patients are usually extremely satisfied [4]. Moreover, patients undergoing EACR are followed by the Plastics and reconstructive department of our institution for pinna reconstruction, often around age 7. The aesthetic aspect is usually satisfactory for these patients as well, with an EAC slightly larger than the other side. Considering that the superior cosmetic aspect of the EACR may play a role in the patient’s final decision especially when CAA is unilateral, that 30% of our EACR group developed similar hearing to the BAHA patients by a supplementary hearing aid, and finally that the remaining patients did not feel the need for an additional hearing aid, our algorithm for CAA is still useful for decisionmaking in the management of CAA. 5. Conclusion Congenital aural atresia is a rarely encountered condition to which experimented otologists may be confronted. EACR alone constituting an attractive option in partial EAC atresia, does not give acceptable audiologic results unless it is combined to a conventional air conduction hearing aid where hearing gain becomes comparable to BAHA implanted patients. BAHA implantation is a reliable, safe and efficient therapeutic option that allows a significantly better audiologic outcome when compared to reconstructive surgery for patients with total congenital aural atresia. Acknowledgement The authors thank the audiologists of the tertiary pediatric care center where the study was done, for all their support.
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References [1] J.A. Veltmann, Y. Jonkers, I. Nuijten, I. Janssen, W. van der Vliet, E. Huys, et al., Definition of a critical region on chromosome 18 for congenital aural atresia by array CGH, Am. J. Hum. Genet. 72 (2003) 1578–1584. [2] P.E. Kelley, M.A. Scholes, Microtia and congenital aural atresia, Otolaryngol. Clin. North Am. 40 (February (1)) (2007) 61–80, vi. [3] A. De la Cruz, K.B. Teufert, Congenital aural atresia surgery: long-term results, Otolaryngol. Head Neck Surg. 129 (July (1)) (2003) 121–127. [4] T. Romo, L.G.T. Morris, S.D. Reitzen, S.N. Ghossaini, J.J. Wazen, D. Kohan, Reconstruction of congenital microtia-atresia: outcomes with the medpor/bone-anchored hearing aid-approach, Ann. Plast. Surg. 62 (April (4)) (2009) 384–389. [5] A.K. Evans, K. Kazahaya, Canal atresia: ‘Surgery or implantable hearing devices? The expert question is revisited’, Int. J. Pediatr. Otorhinolaryngol. 71 (March (3)) (2007) 367–374. [6] R.A. Jarhrsdoefer, J.W. Yeakly, E.A. Aguilar, R.R. Cole, L.C. Gray, Grading system for the selection of patients with congenital aural atresia, Am. J. Otol. 13 (January (1)) (1992) 6–12. [7] F. Declau, C. Cremers, P. Van de Heyning, Diagnosis and management strategies in congenital atresia of the external auditory canal, Br. J. Audiol. 33 (October (5)) (1999) 313–327. [8] M.A. El-Begermy, O.I. Mansour, A.M. El-Makhzangy, T.S. El-Gindy, Congenital auditory meatal atresia: a numerical review, Eur. Arch. Otorhinolaryngol. 266 (April (4)) (2009) 501–506. [9] A. Tjellstrom, B. Hakansson, The bone-anchored hearing aid. Design principles, indications, and long-term clinical results, Otolaryngol, Clin. North Am. 28 (February (1)) (1995) 53–72. [10] C. Bluestone, R. Rosenfeld, Surgical Atlas of Pediatric Otolaryngology, McGrawHill, 2002, pp. 433–438. [11] W.H. Saunders, M.M. Paparella, Atlas of Ear Surgery, Mosby, 1971, pp. 234–243. [12] D. Brackman, C. Shelton, M.A. Arriaga, Otologic Surgery, Saunders, 2001, pp. 58–65. [13] G. Granstro¨m, K. Bergstro¨m, A. Tjellstro¨m, The bone-anchored hearing aid and bone-anchored epithesis for congenital ear malformations, Otolaryngol. Head Neck Surg. 109 (July (1)) (1993) 46–53. [14] R.F. Yellon, Atresiaplasty versus BAHA for congenital aural atresia, Laryngoscope 121 (January (1)) (2011) 2–3. [15] S.O. Chang, B.Y. Choi, D.G. Hur, Analysis of the long-term hearing results after the surgical repair of aural atresia, Laryngoscope 116 (October (10)) (2006) 1835–1841. [16] A.F. Snik, E.A. Mylanus, C.W. Cremers, Aided free-field thresholds in children with conductive hearing loss fitted with air- or bone-conduction hearing aids, Int. J. Pediatr. Otorhinolaryngol. 30 (August (2)) (1994) 133–142. [17] C. Fuchsman, S. Tringali, F. Disant, G. Buiret, C. Dubreuil, P. Froehlich, et al., Hearing rehabilitation in congenital aural atresia using the bone-anchored hearing aid: audiologic and satisfaction results, Acta Otolaryngol. (2010). [18] J.F. Yu, Y.S. Chen, W.D. Cheng, Gain affected by the interior shape of the ear canal, Otolaryngol. Head Neck Surg. 144 (June (6)) (2011) 945–949. [19] A. De la Cruz, F.H. Linthicum Jr., W.M. Luxford, Congenital atresia of the external auditory canal, Laryngoscope 95 (April (4)) (1985) 421–427. [20] K. Nishizaki, Y. Masuda, K. Karita, Surgical management and its post-operative complications in congenital aural atresia, Acta Otolaryngol. Suppl. 540 (1999) 42–44. [21] S. Lloyd, J. Almeyda, K.S. Sirimanna, D.M. Albert, C.M. Bailey, Updated surgical experience with bone-anchored hearing aids in children, J. Laryngol. Otol. 121 (September (9)) (2007) 826–831, Epub 2007 January 9. [22] E.R. Oliver, B.B. Hughley, D.C. Shonka, B.W. Kesser, Revision aural atresia surgery: indications and outcomes, Otol. Neurotol. 32 (February (2)) (2011) 252–258.
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International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Congenital aural atresia: Bone-anchored hearing aid vs. external auditory canal reconstruction Sarah Bouhabel, Pierre Arcand, Issam Saliba * Sainte-Justine University Hospital Center (CHU SJ), University of Montreal, 3175, Coˆte Sainte-Catherine, Service ORL, Montreal H3T 1C5, Quebec, Canada
A R T I C L E I N F O
A B S T R A C T
Article history: Received 31 October 2011 Received in revised form 20 November 2011 Accepted 21 November 2011 Available online 15 December 2011
Objective: To compare the audiologic outcome and feasibility of bone-anchored hearing aid (BAHA) and external auditory canal reconstruction (EACR) surgeries in pediatric patients presenting a congenital aural atresia (CAA). Methods: A retrospective chart review of 40 patients operated in our tertiary pediatric care center between 2002 and 2010 was performed. 20 patients underwent EACR, whereas another 20 patients were implanted with a BAHA device. Air conduction (AC), bone conduction (BC), pure tone average (PTA) and speech discrimination score (SDS) were compared preoperatively, and hearing gain (HG) postoperatively at 6 and at 12 months at frequencies of 500, 1000, 2000 and 4000 Hz. Operative time, complications and associated microtia were documented as well. EACR patients were graded retrospectively upon Jahrsdoerfer’s classification. Results: Preoperative AC were significantly different between groups, at 500, 1000 and 2000 Hz but not at 4000 Hz. BAHA group compared postoperatively to EACR group showed significantly a superior HG of 46.9 7.0 dB (p < 0.001) and of 39.8(7) 7.2(6.9) dB (p < 0.001) at 6 months and at 1 year, respectively. Moreover, aided air thresholds from the EACR group revealed an audiologic status similar to those of the BAHA group patients, at 6 months and one year postoperatively. Both groups had a similar evolution of their BC, as well as of the incidence of complications. We report one case of transient facial paralysis in the EACR group. Total operative time is significantly lower (p < 0.001) for a BAHA implantation (56 21 min) than for EACR surgery (216 174 min). No preoperative or postoperative correlation (Pearson correlation test; p > 0.05) was found between patient’s Jahrsdoerfer’s score and their audiologic outcome. HG does not seem to be influenced by the presence of microtia. Conclusion: EACR, although constituting an attractive option, does not give acceptable results alone. It can however, when combined to conventional air conduction hearing aids, provide excellent audiologic outcomes comparable to BAHA. BAHA implantation is a reliable, safe and efficient therapeutic option that allows a significantly better audiologic outcome when compared to unaided EACR for patients with CAA. ß 2011 Elsevier Ireland Ltd. All rights reserved.
Keywords: BAHA Bone anchored hearing aid Atresia Microtia Ear canal Canal reconstruction Congenital aural atresia Stenosis
1. Introduction Congenital aural atresia (CAA) is a rare malformation of the external auditory canal (EAC). It results from an abnormal embryologic development of the first branchial arch. Whereas most of the cases are sporadic, it is sometimes associated with syndromes like Treacher Collins or with chromosomical abnormalities like 18q deletions [1]. There is a frequent association with microtia. This entity is encountered in about 1 in 10,000 births,
* Corresponding author at: Department of Otolaryngology, Head & Neck Surgery, CHU Sainte-Justine, 3175, Coˆte Sainte-Catherine, Montreal (Qc) H3T 1C5, Canada. Tel.: +1 514 345 4857; fax: +1 514 737 4822. E-mail address: [email protected] (I. Saliba). 0165-5876/$ – see front matter ß 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2011.11.020
predominantly in males (2.5:1 male to female ratio), and usually occurs unilaterally [2]. In 1883, Kiesselbach performed the first documented attempt of surgical correction for this anomaly [3]. The surgical reconstruction option is indeed a challenging therapeutic option, considering the lack of landmarks and the altered anatomy of facial nerve and middle ear [4]. Moreover, it carries many risks for complications, including iatrogenic injury to the facial nerve, EAC restenosis and recurrent otitis externa [5]. The development of grading and classification systems for EAC atresia such as Jarhrsdoefer’s classification has helped in the preoperative evaluation and outcome expectations [6]. However, the bone conduction concept advanced by Tjellstrom in 1980 brought an interesting alternative to the management of this entity [7]. This led to the bone-anchored hearing aid (BAHA) system that is now
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widely used in developed countries [8]. The BAHA is a surgically implantable system that functions through direct bone conduction rather than via the middle ear. Multiple studies have assessed long-term audiologic results and complications of each of the treatment options. However, none has clearly compared in one series strictly the audiologic outcome of both strategies nor stated the superiority of one option towards the other. Of note that Evans et al. in 2007 indeed studied both strategies, but mostly comparing the complications and costeffectiveness of these therapeutic options [5]. Therefore, the purpose of this study is to determine which option would be, for EAC atresia, the treatment of choice regarding the audiologic gain and feasibility. In order to do that, we examined retrospectively our series with both treatment options by comparing and analysing the initial audiologic status of EAC atresia, the postoperative hearing improvement, the complications and the total operating time. 2. Patients and methods We performed a retrospective review and analysis of the medical records of 40 patients (43 ears) who were treated for their EAC atresia in our pediatric tertiary care center, between 2002 and 2010. These patients underwent either surgical EACR (N = 20), or BAHA implantation (N = 20). The decision-making algorithm used in our institution (Fig. 1) was based primarily on the initial degree of the EAC stenosis. If the stenosis was complete, as visualized on the temporal bone computerized tomography (CT) scan (Fig. 2a), BAHA implantation was preferred. However, if the patient presented a partial stenosis (Fig. 2b), we took into account the degree of the ossicular chain malformation. Strong deformation of the ossicles led to BAHA implantation whereas patients with mild malformations and for whom we could not initially offer a conventional hearing aid were considered as a potential candidates for EACR with or without ossiclar chain reconstruction. These patients could benefit from a conventional hearing aid after the EACR. Discussion with the family also oriented the therapeutic choice. We used 3 mm (N = 6) and 4 mm (N = 14) auto-tarauding fixtures for the BAHA patients group. As for the EACR group, 10 out of 20 patients needed ossicular reconstruction simultaneously to the EACR procedure. Of note that microtia was present for 14 patients in the BAHA group and for 7 patients in our EACR group. Three patients had a bilateral external auditory canal atresia, two of them underwent bilateral EACR and one had bilateral BAHA implantation. We took in consideration only the first operated ear for those patients. Moreover, patients from the EACR group were graded retrospectively upon Jahrsdoerfer’s classification (Table 1) to assess the correlation between the malformation severity score
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and their audiologic outcome. Jahrsdoerfer’s score, is a potential radiologic indicative factor of the degree of malformation. 2.1. Surgical techniques Detailed description of the BAHA and EACR surgery can be found elsewhere [9–12]. A single-stage procedure was performed in all our cases of BAHA implantation. A period of 4 months was allowed for osteointegration before BAHA processor fitting. As for reconstructive surgery, the endaural approach was preferred. 2.2. Main outcome measures Evaluation of the hearing improvement for both treatments was done by comparing the preoperative and the postoperative hearing tests. Hearing thresholds at 500, 1000, 2000 and 4000 Hz frequencies were studied for both groups. Pure tone average (PTA) values was defined as the average of AC thresholds at 500, 1000, 2000 and 4000 Hz. Bone conduction (BC), air conduction (AC), PTA and speech discrimination score (SDS) values were compared. We assessed the hearing improvement of BAHA recipients and EACR patients at 6 months and at one-year follow up. Furthermore, regarding the possibility of EACR patients having had revision surgeries, only the final audiogram results were chosen for comparison. The speech discrimination gain was assessed and compared for each group as well. Total operating time for BAHA and EACR, including revision surgeries, were also gathered. Postoperative and intraoperative complications were recorded for each treatment. For the EACR group, we documented the presence or absence of the following most commonly encountered complications, as mentioned through literature: infection, tympanic membrane lateralisation, bony or soft tissue meatal or canal restenosis, facial nerve paralysis, sensorineural hearing loss (SNHL), skin graft failure, wound dehiscence (<1 cm), postauricular hematoma, scar contracture and hypertrophy, and temporomandibular joint pain and trauma. Intraoperative complications assessed were: dura mater lesions, facial nerve and tympanic membrane injury. For the BAHA group, we assessed the presence or absence of: local infection or inflammation, failure to osteointegrate, skin overgrowth, fixture loss and flap necrosis as the postoperative complications. Whereas for the intraoperative complications in this group we identified the presence of haemorrhage or cerebrospinal fluid leak through the drilling site. 2.3. Statistical analysis Variance analysis was conducted, with repeated measures for the intra-subjects frequency factor, as well as for the inter-subjects
Fig. 1. Decision-making algorithm used in our institution. EACR: external auditory canal reconstruction; BAHA: bone-anchored hearing aid.
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Fig. 2. Axial cuts of computerized tomography scan showing a complete (a) and partial (b) external auditory canal stenosis (arrow). Table 1 External auditory canal reconstruction patients graded upon Jahrsdoerfer’s classification and the number of patient (N) in our series with corresponding scores. Points
Parameter [6]
Scoring
Candidacy
Our series (N)
2 1 1 1 1 1 1 1 1 10
Stapes present Oval window opened Middle ear space Facial nerve Malleus/incus complex Mastoid pneumatised Incus-Stapes connection Round window Appearance external ear Total of points
10 9 8 7 6 5 or less
Excellent Very good Good Fair Marginal Poor
0 2 3 3 2 6
group factor. Analysis were done with SPSS software (version 19), using significance threshold fixed at a = 5%.
3. Results 3.1. Patients Age at surgery ranged from 3 to 18 years old, with a mean of 9.2 years old for patients undergoing EACR and 8.5 years old for BAHA recipients. Patients characteristics are summarized in Table 2. None of the patients was excluded. Of the 3 cholesteatoma cases, 2 were from the EAC, as 1 was from the middle ear. Moreover, one patient in the EACR group appeared to have a positive family history of CAA (Table 2). We were able to attribute Jahrsdoerfer’s score to 16 of the 20 patients of the EACR group (Table 1). CT scan were unavailable for 4 patients.
3.2. Audiologic outcome 3.2.1. Air conduction Preoperative air conductions were significantly different between groups, at 500, 1000 and 2000 Hz but not at 4000 Hz. The patients fitted with a BAHA implant had a worse preoperative audiologic status, compared to the patients undergoing EACR surgery (Table 3). At 6 months postoperatively, the mean hearing gain for the EACR group was 2.0 4.6 dB (confidence interval (CI) 95%:[ 11.6– 7.5]) (Fig. 3), whereas patients fitted with a BAHA demonstrated an average hearing gain of 44.9 5.3 dB (CI 95%: [33.8–55.9]) (Fig. 4). We recorded a mean hearing improvement of 46.9 7.0 dB for the BAHA fitted patients at 6 months when compared to the patients of the EACR group (p < 0.001) at 500, 1000, 2000 and 4000 Hz frequencies (Table 4). At one year after surgery, EACR group had an air conduction improvement of 3.5(6) 4.8(5) dB, CI 95% [ 5.8–13.058] (Fig. 3), whereas patients fitted with a BAHA had a mean hearing gain of 43.3 5.2 dB, CI 95% [32.2–54.3] (Fig. 4). The BAHA group presented a mean hearing gain of 39.8(7) 7.2(6.9) dB when compared to the patients in the EACR group (p < 0.001). The improvement appeared to be the same throughout all the frequencies (500, 1000, 2000 and 4000 Hz) (Table 4). 3.2.2. Bone conduction Preoperative mean bone conduction for BAHA group (8.21 10.89 dB) and for the EACR group (9.51 11.44 dB) were not statistically different (p = 0.691).
Table 2 Patient’s characteristics: BAHA group vs. EACR group. Characteristics
BAHA group N = 20
EACR group N = 20
p-values
Sex (male:female) Age (years) Mean SD (range) Side (left:right) Cholesteatoma Associated microtia Family history of CAA
10:10 8.5 3.5 (3–17)
12:8 9.2 4.1 (3–17)
p = 0.525 p = 0.564
7:13 3 14 0
10:10 1 7 1
p = 3.37 p = 0.292 p = 0.027 (<0.05) –
BAHA: bone-anchored hearing aid; EACR: external auditory canal reconstruction; SD: standard deviation; CAA: congenital aural atresia.
Fig. 3. Evolution of the hearing gain at 6 months and at 1 year follow up for the external auditory canal reconstruction group. dB: decibel; Hz: hertz.
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Table 3 Preoperative air conduction and PTA means in decibel (dB) standard deviation (SD) for BAHA and EACR groups. Frequencies (Hz)
BAHA (mean SD) (dB)
EACR (mean SD) (dB)
Difference (mean SD) (dB)
p-Values
500 1000 2000 4000 PTA
73.8 5.4 66.9 4.6 56.1 4.1 50.8 3.7 61.9 4.5
53.0 5.1 50.0 4.5 43.3 4.8 44.6 3.6 47.8 3.7
20.8 7.4 16.9 6.5 11.8 5.6 6.1 5.3 14.2 5.8
p = 0.006 p = 0.007 p = 0.028 p = 0.183 p = 0.015
BAHA: bone-anchored hearing aid; EACR: external auditory canal reconstruction; SD: standard deviation; Hz: hertz; PTA: pure tone average.
No sensorineural hearing loss was noted postoperatively in the two groups. Mean bone conduction remains stable. 3.2.3. Pure tone average PTA values for the EACR group did not show any evolution over time, varying from a mean of 46.1 dB preoperatively, to 51.7 dB at 6 months follow up and to 38.6 dB at one year (p = 0.224). 3.2.3.1. Speech discrimination score. SDS in the EACR group varied from 90.0 7.3% preoperatively, to 75.3 12.1% at 6 months and to 85.0 8.0% at one year follow up. Whereas in the BAHA group, it varied from 88.8 4.6% preoperatively, to 90.0 4.7% and 91.3 3.1% at 6 months and at 1 year follow up, respectively, with no statistically significant difference (p > 0.05). 3.2.4. Impact of preoperative and postoperative factors on audiologic outcome 3.2.4.1. Degree of atresia. The degree of atresia, whether it was complete or partial, showed no significant impact on the audiologic outcome of the BAHA group (p > 0.05). 3.2.4.2. Presence of microtia. Eventhough the distribution of microtia was significantly different between the two groups (14 patients in the BAHA group and 7 patients in the EACR group) (p = 0.027), the presence of microtia did not appear to have impact on the audiologic outcome on each of the two groups (p = 0.406).
3.2.4.5. Air conduction hearing aids. Moreover, 6 out of the 20 EACR patients felt the need for a complementary hearing aid (air conduction hearing aids – ACHA) during the postoperative course. Aided air thresholds of these patients revealed an audiologic status not statistically different to those of the BAHA group patients, at 6 months and at one year postoperatively (p > 0.05) (Table 5). 3.2.4.6. Operating time. Total operating time is significantly lower (p < 0.001) for a BAHA implantation (56 21 min (CI 95%: [25– 100])) than for a EACR procedure (216 174 min (CI 95%: [90–885])). 3.2.4.7. Revision surgeries. Revision surgeries were necessary for 3 cases of the reconstruction group: 1 case for a meatal restenosis, 1 case for a partial ossicular replacement prosthesis (PORP) revision and 1 case for a stapedectomy revision. 3.2.4.8. Complications. In the EACR group, we report one case of transient facial nerve paralysis, 1 case of meatal restenosis (5%) as well as one case of keloid cicatrisation at skin-graft donor site. For the BAHA implantation group, we report 3 cases (15%) of infection around the abutment 4 (N = 2) and 6 (N = 1) months postoperatively, successfully treated with silver nitrate cauterization and a first generation cephalosporin oral antibiotic. We also report 2 cases (10%) of traumatic fixture extrusion, 2 and 4 weeks postoperatively. Overall, the incidence of complication was not significantly higher in one group towards the other (p = 0.273). 4. Discussion
3.2.4.3. Jahrsdoefer’s score. It was obtained for 16 out of 20 patients of the EACR group. The CT scan of the remaining 4 patients were not available. Audiologic results found no preoperative or postoperative correlation (Pearson correlation test; p > 0.05) between patient’s initial Jahrsdoerfer’s score and their audiologic outcome. 3.2.4.4. Ossicular chain reconstruction. In the EACR group, PTA was not different between patients with or without ossicular chain reconstruction (42.6 dB vs. 39.72 dB; p > 0.05) at 6 months and 1 year after surgery.
Fig. 4. Evolution of the hearing gain at 6 months and at 1 year follow up for BAHA group. dB: decibel; Hz: hertz.
Multiple scoring systems to evaluate the EAC atresia patient’s candidacy for surgical reconstruction surgery have been developed throughout years. Jahrsdoerfer’s classification (Table 1) was cited by many authors throughout literature, and this grading system is based mainly on the evaluation of the preoperative temporal bone CT scan and on the appearance of the external ear [6,13,14]. A predictive audiologic outcome is then determined from the patient’s score. According to this classification, a score of 5 or less disqualified patients as candidates for reconstruction. Consequently, a study conducted by Granstro¨m et al. strongly recommended the implantation of BAHA in patients scoring less than 6 points[13]. Eventhough 6 of our EACR group had a score of 5 or less, we were not able to detect any correlation between the attributed Jahrsdoerfer’s score and the degree of hearing improvement or EAC restenosis in our series. Sex distribution was even in our population (p = 0.525), despite the male predominance reported in the literature[2]. Both groups initially appeared to be similar, except for the microtia distribution. 14 cases of microtia were included in the BAHA group, compared to 7 cases for the EACR group (p = 0.027). This difference in the distribution could not be explained by the decision making algorithm used in our establishment, since it does not take this factor into account. However, Chang et al. reported a poorer audiologic outcome in patients with microtia grade II or III undergoing reconstruction surgery, even if they were initially considered relatively good candidates following Jahrsdoerfer’s classification (<6 points) [6,15]. The risk for restenosis, as well as
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Table 4 Mean hearing gain expressed in decibel (dB) standard deviation (SD) at 6 months and 1 year after surgery. Follow up
BAHA (mean SD) (dB)
6 months 1 year
44.9 5.3 43.3 5.2
EACR (mean SD) (dB) 2.0 4.6 3.5 4.8
Difference between the two groups (mean SD) (dB)
p-Values
46.9 7.0 39.8 7.2
<0.001 <0.001
BAHA: bone-anchored hearing aid; EACR: external auditory canal; dB: decibel; SD: standard deviation; Hz: hertz.
for consequent revision surgery for these patients was higher. Considering the lack of details in the medical charts regarding the degree of microtia, we could not evaluate the effect of this variable on our population. We can however conclude that the over representation of this characteristic in the BAHA group is related to the higher number of total stenosis. However this factor did not have any impact on the hearing gain in this group because we bypass the EAC and the middle ear effect. Patients undergoing EACR, with or without ossicular reconstruction, showed a poor audiologic outcome. Evans et al. obtained a mean hearing gain of 17.7 dB [ 12.5–42.8], Chang et al. reported a mean hearing gain of 20 dB, while Granstro¨m et al. had improvements varying from 0–10 dB for 24 patients, to 10–30 dB for 19 patients and more than 30 dB for 5 patients [5,13,15]. Overall, patients who underwent reconstruction surgery for their congenital aural atresia (CAA) in our cohort did not have a statistically significant hearing improvement. However, they reported a clinical subjective hearing improvement, which was stable over time. Only 30% of our series (6/20) needed a conventional hearing aid during their postoperative course. Their obtained aided thresholds were extremely satisfactory, showing values similar to the postoperative BAHA results, at 6 months and 1 year follow up. Moreover, the obtained values fall within the expected values for aided thresholds for children with conductive hearing loss (15– 20 dB) [16]. Air conduction hearing aid therefore seems to be of a great improvement to the audiologic status of the reconstructed patients. However, 14 patients from the EACR group felt no need for a supplementary hearing aid. The paucity of patients feeling the need for auditory hearing aid is most probably caused by the fact that patients chosen for EACR already had a certain degree of middle ear formation (Fig. 1). The satisfaction in their audiologic status may also be due to the fact that their contralateral ear is normal in most cases. BAHA also seems to constitute a great alternative when EACR fails to provide the expected results. Accordingly, Granstro¨m et al. reported that 16 patients out of 44 were fitted with a BAHA implant after an ossicular chain reconstruction surgery and that all the 16 patients subjectively reported a significant improvement of their hearing capacities [13]. Moreover, Evans et al. reported that 93% of the patients who underwent surgical reconstruction needed a form of amplification postoperatively. None of the patients from our series developed any postoperative sensorineural hearing loss, therefore speech discrimination score did not show any clinical or statistical difference between groups. The fact that the patients fitted with a BAHA had a worse preoperative air conduction when compared to the patients undergoing reconstructive surgery can be explained by the decision-making algorithm used for patient selection. Indeed, Table 5 Mean aided thresholds (dB) for external auditory canal reconstruction and bone anchored hearing aid (BAHA) patients. Frequencies (Hz)
Mean aided threshold (mean SD) (dB)
BAHA at 6 months
BAHA at 1 year
500 1000 2000 4000
23.75 4.79 16.25 13.15 12.50 11.90 21.25 6.29
17.9 10.0 15.8 9.0 16.6 8.3 25.8 13.0
18.3 7.1 17.9 6.9 20.4 8.9 22.1 11.4
dB: decibel; SD: standard deviation; Hz: hertz.
patients with complete stenosis were provided with a BAHA implant. Consequently, EACR patients would not acquire the resonance effect provided by the EAC because of the partial stenosis explaining as well the absence of difference at 4000 Hz [18] with the BAHA group. Patients fitted with a bone-anchored hearing aid benefited from a tremendous hearing improvement much better than patients who underwent EACR. The mean hearing gain obtained 44.9 5.3 dB [CI 95%: (33.8–55.9)] at 6 months and 43.3 5.2 dB [CI 95%: (32.2–54.3)] at one year is similar to the values encountered through the literature [5,17] and appeared to be stable over time as well, considering our one year follow up. The implantation of a bone-anchored hearing aid appears to be a significantly more efficient approach to provide a substantial hearing improvement for patients presenting with CAA. The BAHA implant allows a bone-conducted transmission of sound directly through the cochlea, whereas postoperative EACR is still dependant on the external and middle ear that BAHA implants permit to bypass. The efficiency of the BAHA is therefore in part due to the inherent nature of the device, since it provides predictible results that do not depend solely on the degree of malformation of the middle or external ear [17]. The incidence of complications in our population was compatible with literature complication rates. The 5% occurrence of restenosis in the EACR group is lower than the reported range of 8–29% [19,20] because in our algorithm we perform EACR only for partial EAC atresia. Accordingly, the 10% (2/20) occurrence of fixture loss in the BAHA group appeared to fit within reported limits of 5–29% [21]. However, these few cases were traumatic and happened before the 4th month after implantation and are not cases of implant rejection. Oliver et al. reported in this pediatric series 22 fixture loss out of 71 implantations, and 77% of them were non traumatic [22]. Our fixture loss rate, being mainly traumatic, may therefore be lower than reported rates in the literature. The two-staged BAHA system placement is the standard management described in the literature for BAHA in children. However, single-stage BAHA placement is the standard technique in our pediatric center. It is efficient and safe [4,21]. Single-staged BAHA indeed avoids a second procedure and provides an earlier hearing rehabilitation. Evans et al. reported that single-stage BAHA implantation yields an even greater cost savings at just over one quarter of the cost of surgical EACR [5]. All complications of the single-stage were related to skin reaction. In our series, the 15% occurrence of granulation at the surgical implantation site was higher than reported data (4.5%) [4]. Considering that skin infection may often be self-limited and locally treated by patients or their parents, this complication might be underreported in certain studies. Despite the fact that the strict incidence of complications between groups was not statistically different (p = 0.273), there indeed is a difference regarding their severity. The complications encountered in the EACR group such as meatal restenosis and transient facial nerve injury, require much more care when compared to the surgical site infections or to the fixture loss in the BAHA group. In our series, revision surgeries appear to be more commonly encountered in patients undergoing reconstruction surgery, as reported by Chang et al. (26.6% of their studied population). The most common cause for revision surgery is meatal restenosis
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(58%), followed by conductive hearing loss (20%) and chronic drainage or infection (19%), as stated by Oliver et al. [22]. BAHA implant indeed constitutes a reliable device. Patient satisfaction is extremely good and there is consequently a noteworthy improvement in their quality of life[21]. The procedure is of course less demanding in term of operative time as well, as demonstrated in this study. From a strictly audiologic standpoint, it is obvious that BAHA implantation gives superior results when compared to surgical EACR. However, post operative outcomes of EACR patients supplemented with hearing aids seems to be similar to BAHA group patients outcomes. From a cosmetic standpoint, it is of note that patients from the BAHA group usually let their hair grow more from the side of the implant. With time, the implant is less visible and patients are usually extremely satisfied [4]. Moreover, patients undergoing EACR are followed by the Plastics and reconstructive department of our institution for pinna reconstruction, often around age 7. The aesthetic aspect is usually satisfactory for these patients as well, with an EAC slightly larger than the other side. Considering that the superior cosmetic aspect of the EACR may play a role in the patient’s final decision especially when CAA is unilateral, that 30% of our EACR group developed similar hearing to the BAHA patients by a supplementary hearing aid, and finally that the remaining patients did not feel the need for an additional hearing aid, our algorithm for CAA is still useful for decisionmaking in the management of CAA. 5. Conclusion Congenital aural atresia is a rarely encountered condition to which experimented otologists may be confronted. EACR alone constituting an attractive option in partial EAC atresia, does not give acceptable audiologic results unless it is combined to a conventional air conduction hearing aid where hearing gain becomes comparable to BAHA implanted patients. BAHA implantation is a reliable, safe and efficient therapeutic option that allows a significantly better audiologic outcome when compared to reconstructive surgery for patients with total congenital aural atresia. Acknowledgement The authors thank the audiologists of the tertiary pediatric care center where the study was done, for all their support.
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