Bilateral Simultaneous Cochlear Implantation in Children: Our First 50 Cases

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1 The Laryngoscope VC 2009 The American Laryngological, Rhinological and Otological Society, Inc. Bilateral Simultaneous Cochlear Implantation in Children: Our First 50 Cases James D. Ramsden, FRCS, PhD; Blake C. Papsin, MD; Randy Leung, MD; Adrian James, FRCS; Karen A. Gordon, PhD Objectives/Hypothesis: To assess the safety and surgical technique of bilateral simultaneous cochlear implantation in children. Study Design: Prospective case series at a tertiary academic pediatric hospital. Methods: Surgical times, complications, and patient outcomes are reported from the first 50 consecutive simultaneous cochlear implants performed at the Hospital for Sick Children between 2005 and These results were compared to the same measures in a group of sequentially implanted children consecutively implanted from 2001 to Results: The group of children receiving simultaneous bilateral cochlear implants showed no difference in complications, length of hospital stay, or use of analgesia and antiemetics compared with children receiving single implants. The simultaneously implanted children had a reduced cumulative surgical time and hospital stay than is required for bilateral implantation performed sequentially. Conclusions: Bilateral simultaneous cochlear implantation in this series of children was safe and required no significant increase in surgical time and hospital stay compared with unilateral procedures. Key Words: Sensorineural hearing loss, bilateral cochlear implantation, simultaneous cochlear implantation. Laryngoscope, 119: , 2009 INTRODUCTION Cochlear implantation has transformed the lives of children with profound sensorineural hearing loss, restoring hearing and improving quality of life. Increasingly there is recognition that hearing with a unilateral implant still requires considerable effort, particularly in From the Cochlear Implant Program, Department of Otolaryngology, Hospital for Sick Children, Toronto, Canada. Editor s Note: This Manuscript was accepted for publication June 15, Send correspondence to James D. Ramsden, FRCS, PhD, ENT Department, John Radcliffe Hospital, Oxford, OX3 9DU, UK. james.ramsden@orh.nhs.uk DOI: /lary noisy situations. Although progress is still needed in many areas, the issue of unilateral hearing may be immediately resolved by providing bilateral cochlear implants. 1 Outcomes of bilateral cochlear implantation in children will take some time to accumulate. At this time, there is a pressing need to ascertain whether bilateral cochlear implantation in children is safe. Concerns regarding bilateral implantation include the potential effects on vestibular function, risks of surgery, and, not least, the cost-effectiveness of providing two cochlear implants. 2,3 Binaural advantage improves speech understanding, particularly in background noise, enhances sound localization, and subjectively improves quality of life. 4,5 There are good reasons to expect that children might benefit from bilateral rather than unilateral cochlear implantation. Our group has already suggested that provision of bilateral cochlear implants simultaneously at young ages might yield the best outcomes for children who are deaf to develop binaural hearing. 1 Several groups have reported simultaneous cochlear implantation in adults, 6,7 but there are no large reported case series of pediatric simultaneous cochlear implantation. Simultaneous implantation has additional concerns compared with single implantation, including prolonged operative time, additional blood loss in small children, and bilateral complications, including the dreadful possibility of bilateral facial nerve palsies. However, simultaneous implantation has many potential advantages, including shorter overall operative time and potentially briefer cumulative hospital stay, a single course of auditory rehabilitation, and possibly better speech and language outcomes compared to sequential implantation. Since 2005 we have provided >130 children with bilateral cochlear implants. We began providing bilateral cochlear implants simultaneously at the end of 2006, and have since assessed every child applying to our program for simultaneous bilateral cochlear implant candidacy. In the present study, we report our surgical outcomes concentrating on the safety of the simultaneous procedure. Data regarding development of hearing after simultaneous bilateral cochlear

2 TABLE I. Demographics and Surgical Time of the Simultaneous, Single, and Sequential Bilateral Cochlear Implant Groups. No. (Male) Age at Implant (mo) Weight (kg) % of ASA >1 Total OR Time (hr:min) Surgical Time (hr:min) Simultaneous 50 (28) :1538 4:1635 Single 55 (29) :2233* 2:4936* Short sequential 17 (11) :2833* 2:5027* Long sequential 38 (18) * * :4330* 2:4924* Cumulative 55 (29) 7:0149* 5:3945* The cumulative group is the summed time of individual children s single and sequential operations. *P <.0001 (all vs. simultaneous group). P <.01. P <.05. ASA ¼ American Society of Anesthesiologists grade; OR ¼ operating room. implantation will be available in the future as the children progress with their implants. MATERIALS AND METHODS Data from a consecutive series of children receiving bilateral cochlear implants over the period 2001 to 2008 at the Hospital for Sick Children were analyzed. We compared the first 50 simultaneous bilateral cochlear implants (50 bilateral cochlear implant operations), with a control group of 55 sequentially implanted children (110 unilateral cochlear implant operations). Because almost all of the children received their first implant at young ages ( months; median, 15.3), we divided the group of children receiving bilateral implants sequentially into two groups. The first group was made up of 17 young children who had only 6 to 12 months of unilateral implant use prior to receiving the second implant at ages 17.4 to 165 months (median, 26.7 months) (short delay sequential group). The second group consisted of 38 older children, 38.9 to 128 months of age (median, 68.5 months), who had over 2 years of unilateral implant experience at the time the second ear was implanted (long delay sequential group). For the sequentially implanted children, factors related to implantation of the first ear were analyzed separately from those related to implantation of the second ear. All children being considered for first cochlear implantation were assessed for inclusion in our bilateral cochlear implant research protocol using the following inclusion criteria: Aged 8 months to 18 years at study entrance. Cochlear implant candidate as determined by the multidisciplinary cochlear implant team at the Hospital for Sick Children. 8 Severe to profound sensorineural hearing loss with a pure tone average of no better than 80 db hearing loss in the ear to be implanted. Enrollment in a habilitation/educational program with an emphasis on spoken language development. Exclusion criteria for this study were: Medical or psychological conditions that would contraindicate cochlear implant surgery. Developmental disabilities or other conditions that would limit the pediatric candidate s ability to participate fully in the study. Hearing loss of neural or central origin. Unrealistic expectations on the part of the candidate s family, regarding the potential benefits, risks, and limitations inherent to the surgical procedure and prosthetic device. Unwillingness or inability of the pediatric candidate or family to comply with all investigational requirements. Information was collected from the electronic patient record specific to the duration of the operation, surgical time, postoperative need for blood transfusion, postoperative analgesia requirements, duration of hospital stay, and perioperative complications. Statistics Student t tests were used to compare postoperative medications, surgical time, total operating room time, and duration of hospital admission in the two groups (simultaneous vs. sequential bilateral cochlear implantation). RESULTS Surgical Time The length of surgical time required for a single cochlear implant was not significantly different between the first and second implant in either the short or long sequential groups (t [109] ¼ 0.1; P >.05). In contrast, simultaneous bilateral cochlear implant surgery took longer (4 hours, 16 minutes 35 minutes) compared to single (both first and second) implant surgeries (2 hours, 49 minutes 33 minutes), and this difference was statistically significant (t [103] ¼ 12.53; P <.0001) (see Table I). A cumulative total surgical time for each individual child in the sequential groups was calculated by adding the duration of the two operations. The total surgical time required was 5 hours, 39 minutes 45 minutes, which was longer than the surgical time for the simultaneous implant surgery (t [103] ¼ 10.5; P <.0001). Setup Time in the Operating Room The setup to prepare the patient for simultaneous implantation was more complicated than single-side surgery, irrespective of whether it was the first or second implant, as bilateral facial nerves were monitored and additional care was paid to positioning the head to allow the best access to both ears. The setup time was therefore longer (58 minutes 20 minutes) in the group of children undergoing simultaneous bilateral cochlear implantation compared to single implantation in the short 2445

3 delay sequential group (first ear, 40 minutes 13 minutes; second ear, 37 minutes 12 minutes) and the first ear in the long delay group (first ear, 30 minutes 14 minutes) (P <.001, t test). Implantation of the second ear in the long delay sequential group took longer to set up (53 minutes 17 minutes) than implantation of the first ear (30 minutes 14 minutes) (t [74] ¼ 6.4; P <.0001). These children were older, by the nature of the long delay between implants, and so further analyses were completed to explore the effects of age on setup time. A weak but significant Pearson correlation was found between setup time and age at implantation (R 2 ¼ 0.226, P <.005). Linear regression analysis indicated that this increase was small (B ¼ seconds/ month of age). Total Operating Room Time A cumulative total operating room time for each individual child in the sequential groups was calculated by summing the duration of the two operations. This cumulative operating room time was significantly longer in both the short and long delay sequential bilateral cochlear implant groups (6:47 44 minutes, 7:05 50 minutes, respectively) compared to the operating room time required in the children receiving simultaneous bilateral cochlear implants (5:15 38 minutes), short delay versus simultaneous (t [65] ¼ 8.283; P <.0001), and long delay versus simultaneous (t [86] ¼ ; P <.0001). Analgesia and Antiemetic Use It is possible that bilateral surgery is more painful or produces greater nausea than single-sided cochlear implant surgery. Data was collected on analgesia and antiemetic use during the hospital admission. As the actual dose of medication was dependent on the child s weight, the number of doses of medication required during their hospital admission was analyzed. Mean data for use of acetaminophen, Gravol (dimenhydrinate), and codeine for all three groups are shown in Figure 1. Data was not collected on postdischarge analgesia. Fig. 2. Length of hospital admission following simultaneous bilateral, single implant, short and long sequential cochlear implantation. The cumulative sequential is the hospital stay of the first and second admission summed. ***P <.0001 versus simultaneous implant group. The use of acetaminophen was not significantly different for children undergoing simultaneous bilateral cochlear implantation group compared to their peers who received a single cochlear implant (t [103] ¼ 1.079; P >.05), or the short sequential implant (t [66] ¼ 0.97; P >.05). Fewer doses of acetaminophen were required by the long sequential group (t [103] ¼ 2.8; P <.01) than the simultaneous groups. However, fewer doses of codeine were required after single ear implantation (first implant or second implant) than after bilateral simultaneous implantation ( vs , t [158] ¼ 3.0; P <.01). Dimenhydrinate requirements were the same with bilateral simultaneous and first (single) implantation (t [103] ¼ 0.82; P >.05) and short sequential implantation (t [66] ¼ 0.83; P >.05), but was increased in the long sequential group (t [86] ¼ 2.1; P <.05). Further analysis indicated that analgesia requirements decreased with age (doses of acetaminophen with age: Sp ¼ 0.316; P <.0001, doses of codeine with age: Sp ¼ 0.227; P <.005) and that antiemetic needs increased with age (doses of dimenhydrinate: Sp ¼ 0.156; P ¼.05). Hospital Stay Figure 2 plots the mean hospital stay after simultaneous bilateral implantation, single implantation of the first ear, and single implantation of the second ear in the short and long delay sequential groups. The mean cumulative hospital stay for children receiving bilateral cochlear implant sequentially is also shown. Whereas the sequential group cumulatively spent days in hospital, the simultaneous group spent days in hospital (t [103] ¼ 10.81; P <.0001). Fig. 1. Analgesia and antiemetic requirements during hospital admission following simultaneous bilateral, single implant, short and long sequential cochlear implantation. *P <.05 versus simultaneous implant group Complications Four patients in the simultaneous group (8% of 50 patients, 8% of 50 operations) had an extended stay in hospital (two for fever, one for nausea, and one for clear otorrhea, which settled after observation and was negative for b 2 transferrin). After single implantation

4 (of either the first or second ear) four patients required longer stay (7.2% of 55 patients, 3.66% of 110 operations), two for fever, one for nausea, and one proven cerebrospinal fluid leak. There were no postoperative complications in the simultaneous group, and three minor complications (prolonged fever, acute otitis media, and small mastoid abscess) after single implantation (5.4% of 55 patients, 2.7% of 110 operations). DISCUSSION There is increasing evidence supporting bilateral cochlear implantation in deaf children to improve access to sound. It is known that earlier implantation leads to better outcomes in prelingually deafened children, 9 12 with most centers now aiming for implantation around the age of 1 year. However, it is not proven whether simultaneous implantation gives better outcomes compared with sequential, and there is controversy regarding the timing of implantation in small children. This paper reports a consecutive series of 50 simultaneous implants compared with a control group of sequentially implanted children. There was a significant reduction in surgical time in the simultaneous group compared to the cumulative surgical times in the children receiving bilateral cochlear implants sequentially. Interestingly, despite the increased complexity of setup in simultaneous bilateral procedures, setup time was not significantly different in this group compared to setup time of the second ear in children in the long delay group. A significant relationship was found between setup time and age, which might reflect increased anesthetic time for older children who require more counseling and preparation for anesthesia than babies. We have found no increase in complications related to surgery in the simultaneous group. Furthermore, this group did not require significantly more analgesia or antiemetic during their hospital admission, and their hospital stay was not longer than for single implants. Weak but significantly negative correlations were found between age and analgesic doses, whereas antiemetic doses showed some increase in dosage with age. This may simply be because older children may be more clearly able to express that they feel sick rather than that they are in pain, and therefore are given more antiemetic and less analgesic. Overall, the simultaneous bilateral group had a shorter cumulative total hospital stay than the sequentially implanted children, and they were able to progress to auditory rehabilitation without requiring further surgery. This confirms our impression that the families who find the process of bilateral cochlear implantation the most challenging are the short sequential group, who are readmitted a few months after major surgery and during their auditory verbal habilitation, and then have to go through the whole process again. To perform prolonged surgery in infants requires an experienced anesthetist, who is able to maintain a good operative field for the duration of the surgery and suitable postoperative care, although we have not found these children more difficult to manage than single implanted children. There must be careful preoperative assessment, especially to anticipate surgical difficulties that may delay the progress of the operation. There must be an understanding by both parents and surgical team that the operation may be concluded at the end of the first implant if there are significant operative complications or concerns, although this did not occur in this series. We now assess all children attending the Hospital for Sick Children Cochlear Implant Program for simultaneous bilateral implantation, and there is increasing expectation from parents that this will be the optimum treatment for their deaf children. These children are part of an intensive research program and we look forward to reporting their speech and language outcomes in the near future. CONCLUSION Bilateral simultaneous cochlear implantation in pediatric facilities by experienced surgical teams does not cause increased hospital stay, extra complications, or greater morbidity compared with single-sided implantation. This is likely to lead to correspondingly better costeffectiveness for bilateral implantation than sequential implantation. More importantly, simultaneous implantation is probably the optimum rehabilitation of profoundly deaf children, and further work to establish this will be built on the surgical safety of simultaneous cochlear implantation. BIBLIOGRAPHY 1. 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