Cochlear Implantation in Children with Otitis Media

Abstract

One of the concerns during the cochlear implant candidacy process is the presence of chronic otitis media which could delay the implantation process. The aim of this study was to evaluate the surgical difficulties and the long-term complications in children with otitis media and to examine whether it is necessary to delay the implantation until the infection is resolved. The study used a comparative retrospective design based on chart review of all patients who received their implant(s) from January to December of 2012. A total of 200 patients were identified and were followed for 4 years post surgery. Patients were divided into three groups based on their history of otitis media (non-otitis media, chronic otitis media with effusion, and acute otitis media). Data included long-term complications, operative time and duration from first clinical visit to the time until implantation was received. None of study participants had long-term complications during the study period. The operative time was longer in the acute otitis media group with a difference of 45 min. The average delay in cochlear implantation due to the presence of otitis media in chronic group was more than 5 months. Pediatric patients with otitis media could be implanted in one stage safely and effectively.

Introduction

Cochlear implant (CI) has become the standard care for hearing rehabilitation in children with severe to profound hearing loss. Generally, the number of young children receiving cochlear implantation is increasing worldwide. The surgical risks of the procedure are considered very minimal; wound infection is the most commonly occurring complication [1, 2]. Special measures are typically taken to reduce infection post surgery. Antibiotics are given intravenously prior to surgery and applied locally before electrode insertion. However, the incidence of infection is likely to be increased when bacterial pathogens from existing infection are present at the time of surgery. Therefore, if an active infection is confirmed prior to the surgery, cochlear implantation will be contraindicated until the infection is resolved.

However, young children are susceptible to otitis media (OM) which is a common middle ear infection during childhood. Some reports showed that eighty-four percent of all children had at least one episode of OM, and 50% had three episodes or more during the early years [3]. The presence of chronic middle ear infection during CI candidacy assessment poses a significant concern due to the risk of possible spread of infection to the cochlea and the intracranial spaces. The complications that might be the cause for concern vary from wound infection to meningitis which can be fatal in some cases. Some studies reported that the incidence of infectious complications in patients with CIs range from 1.7 to 4.1% [4, 5].

Many studies examined the rate of complications and safety of cochlear implantation in pediatric population. For example, Kempf et al. reviewed 366 children who underwent cochlear implantation. It was reported that 5.6% of this group developed OM after implantation which was managed with conservative treatment approaches; however, two patients with severe infection required surgical removal of their CI devices [6]. Additionally, in another study, tympanocentesis and ventilation tube placement was performed in a total of 246 children who had chronic OM. Culture was obtained from 506 ears; results showed normal flora in 47% of the tested children, no growth in 35%, Haemophilusinfluenza in 9%, Streptococcus pneumonia in 4%, Moraxella catarrhalis in 3% and Staphylococcus aureus in 2% [7].

On the other hand, a large cohort study on children younger than 6 years reported that the incidence of developing meningitis post implantation was 30 times higher than the general population [8]. This may necessitated device explantation in cases of intractable infection and was reported to be fatal in some cases [4, 5, 8, 9]. The incidence of post CI meningitis is still reaching up to 20 cases every year despite measures taken during the CI evaluation and using certain surgical techniques that aim to minimize the risk of meningitis; this includes sealing the cochleostomy with an autograft material like fascia [10]. In general, these reports may suggest that it might be necessary to minimize the risks associated with OM prior to the CI surgery in order to control for meningitis.

In children, the possibility of surgical complication and intraoperative difficulty associated with OM has been suggested to have an influence on the timing of the surgery which may necessitate further intervention before implantation [11]. However, it is well known that early implantation has better rehabilitative outcome. Therefore, it is important to examine whether implantation should necessarily be delayed until OM can be managed. The aim of this study was to evaluate the CI surgical difficulties and long-term complications in children with OM.

Material and Methods

This study used a chart review design. Specifically, charts were reviewed for patients who underwent CI surgery between January 1st, 2012 and December 31st, 2012. Two hundred records were reviewed. Patients who were older than 18 years (n = 24), had auditory brainstem implant (n = 1), reimplantation (n = 3), and patients with incomplete data (n = 7) were excluded. This study was approved by the institutional review board committee (protocol no. E-12-777).

A total of one hundred sixty-five patients was included in this study. One hundred forty-five patients were implanted unilaterally and twenty patients were implanted bilaterally. One hundred thirty-four patients were identified as non-otitis media CI candidate and thirty-one patients in total were diagnosed with otitis media (OM) (see Fig. 1). Of the OM patients, seventeen were previously treated prior to the CI surgery while fourteen patients were diagnosed intraoperatively.

Fig. 1.

Distribution of patients is shown. Patients were categorized into three groups: Non-OM, OME, and AOM

Based on the above patients’ demographics, CI patients in this study were divided into three groups: Non-OM; chronic otitis media with effusion (OME), and acute otitis media (AOM). Specifically, the OME group was defined as those patients who had a history of chronic OM but no clinical evidence of active infection 3 months prior to implantation. On the other hand, the AOM group was defined as those patients who found to have signs of OM like granulation tissue or effusion intraoperatively but had no evidence of infection preoperatively. The remaining patients were labelled non-OM as they did not have a clinical history of OM. All patients were followed for a period of 4 years post surgery.

Pre-operative evaluations, surgical reports, postoperative inpatient period, and clinic follow up were analyzed retrospectively for the three groups. In addition, the time from first presentation to implantation, and the operative time from cutting to closure have been compared. The collected data were analyzed and represented using the SPSS 21. T-tests were performed using statistical significance level of 0.05.

Results

Preoperative Assessment

All patients in the OME group had a documented history of OM which was treated medically in 15 patients while 2 patients underwent ventilation tube insertion due to failure of the medical therapy. The majority of this group (76.5%) had a type A tympanogram suggesting normal middle ear system peak pressure and mobility (see Fig. 2). On the other hand, the majority of the AOM had an abnormal preoperative tympanogram with no positive history of OM.

Fig. 2.

Types of preoperative tympanogram are shown for the three groups of patients

Intra-operative Procedure

Both of cochleostomy and round window (RW) surgical techniques were used in this study. In general, the majority of patients in this study underwent cochlear implantation using the RW approach. Interestingly, 57% of the AOM group received their implant using the cochleostomy surgical technique. In the other two groups, the cochleostomy approach was used in only 47% of the OME group and 42% of the Non-OM group. These results perhaps indirectly represent the intaoperative difficulties in indentifying the anatomical landmarks, especially the RW in the AOM group (see Fig. 3).

Fig. 3.

The percentage of cochleostomy versus round window surgical approach is shown for the three groups of patients

The duration of the CI surgery was compared among the three groups to indicate the difficulty encountered during the surgery. The duration of the CI surgery was calculated from the time the skin was cut until the time it was closed. Results showed that the CI Non-OM group had the shortest operative time (1 h: 40 min). The longest surgical time was found in the AOM group which was about 2 h and 25 min, skin-to-skin. The mean operative time for the OME group was 2 h and 6 min (see Fig. 4). The surgical duration was found statistically significant across the three groups (p < 0.01), with the longest in the AOM group.

Fig. 4.

The surgical duration is compared for the three groups of patients

In the current study, only two patients developed complications. The first patient developed wound infection while the other had hematoma. Both of the patients were in the Non-OM group and were treated conservatively. No complications were reported in the other two groups.

Delay in Implantation

The delay in implantation due to the presence of OM was also considered in the current study. The time elapsed between patient’s first visit to the implant center to the time the CI was actually received was calculated for the three groups. Results showed that, compared to the other two groups, the OME group had the longest delay (p < 0.05) which was 578 days on average (see Fig. 5). The difference between the OME and the AOM groups was 171 days. These results suggest that presence of OM can delay the implantation process by more than 5 months which may negatively affect the CI Rehabilitation outcome.

Fig. 5.

The average time duration to receive implantation from patient’s first presentation to the surgery is compared for the three groups of patients

Discussion

Cochlear implantation is the treatment of choice in most children with severe to profound sensorineural hearing loss. In the present study, there were no adverse events reported as a result of the CI surgery. Generally, none of the children in the current study developed major complications post surgery. This was true for all study participants. However, two patients from the Non-OM group developed complications that included wound infection and hematoma. Both cases were treated conservatively and patients reported no further issues. Overall, these results demonstrated the safety of cochlear implantation in young children; this is in line with previous studies demonstrating similar findings [6]. Additionally, current results further extend previous studies by demonstrating the safety of cochlear implantation in children with OM. Study participants were followed for 4 years post implantation and there were no complications reported during the study period.

In general, there is a concern about the potential role that OM could play in complicating the CI procedure [12]. For instance, there is a possibility that OM could cause the implanted electrode in the mastoid and middle ear to become an infected foreign body. Specifically, in chronic OM, the RW can be considered as a pathway for spread of infection to the labyrinth. However, Franz [13, 14] reported that infection can be induced in cat ears and that the RW is relatively impermeable to infections. Additionally, a different study that induced streptococcus pneumonia after implantation in an animal model showed that the incidence of labyrinthitis in implanted ears was not different than that in un-implanted ears. Furthermore, the incidence was decreased if fascia or gel foam was used at the RW to protect the implant [15]. These results generally suggest that implantation does not increase the risk of spread of infection to the inner ear.

Alternatively, a different investigation reported on nine CI devices that were explanted due to device failure. This investigation confirmed the formation of bacterial biofilms on the surface of the explanted electrodes under electronic microscopes despite the fact that there was no evidence of infection prior to the CI surgery. Specifically, one implant was found to contain biofilms of coccoidal shaped bacteria on the middle ear part of electrode [16]. Therefore, biofilms can be one of the important factors responsible for persistent infectious diseases. Biofilms are communities of bacteria enclosed in a self produced polymeric matrix. They have effective defence mechanisms against the immune system of their host and antimicrobial agents. Biofilms are known to adhere to the surface of biomaterials and are involved in many challenging infections [17–19].

The extent to which bacterial biofilms can be a concern in this study cannot be determined since none of the patients required device removal which would have allowed the examination of electrode surface for formation of biofilms. In general, the lack of complications in the present study in both OM groups suggests that cochlear implantation in children with OM can be safe and that delaying the process in order to resolve the infection might rather be unnecessary. These results are consistent with a previous report demonstrating that the prevalence and complication rate of OM in children with CI is the same as in children with normal hearing [20]. It is necessary to reproduce these results at multiple centers to ensure safe and high-quality patient’s care. Generally, our results support earlier reports suggesting that cochlear implantation in patients with OM does not increase the risk of infection.

Current results further demonstrated that the presence of OM results in delaying the implantation process by more than 5 months on average. Delaying implantation in order to resolve OM infection is a common practice that is followed to minimize the risk of infection post implantation. However, this delay might be unnecessary as demonstrated by the current study. Additionally, this can be supported by a study by Fayad and his colleagues who reviewed the medical records of 126 patients younger than 48 months with 144 implants. Their results supported the safety of cochlear implantation in children with history of OM and further suggested that delaying the implantation process to control OM is relatively unnecessary [3]. Generally, by reducing the waiting period to receive CI, early implantation can be achieved which may optimize the CI outcome especially in young children. Early implantation has been shown to facilitate speech and language acquisition and potentially integration into an oral communication environment [21]. Therefore, it is crucial to implant as early as possible.

However, the presence of OM might increase the intra-operative difficulty of the CI surgery. Current findings demonstrated longer surgical duration in the AOM group compared to the other two groups. This was mainly attributed to the increased difficulty in identifying the anatomical landmarks. Surgeons typically use landmarks including the RW and the facial recess in order to place electrodes in the scala tympani. Correct identification of the anatomical landmarks in CI surgery may help in avoiding damage to important structures such as the facial nerve and chorda tympani [22]. In the current study, none of the study participants developed complications post surgery despite the increased difficulty in landmark identification in the AOM group. These results might highlight the importance of the surgeon’s experience in more challenging implant cases.

Conclusion

Occasionally, children can be presented with OM during the assessment for cochlear implantation. In patients with chronic OM, the implantation could be considerably delayed until the infection is cleared. The aim of the current study was to evaluate the surgical difficulties and the long-term complication in children with OM who underwent cochlear implantation and to examine whether it is necessary to delay the implantation until the infection is resolved. Current results revealed that CI is generally safe in children with OM and that delaying the implantation process might rather be unnecessary.

Compliance with Ethical Standards

Conflict of interest

the authors have no conflict of interest to disclose.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study formal consent is not required.