Cochlear reimplantation: surgical techniques and functional results.

OBJECTIVES/HYPOTHESIS: The most common indication for cochlear reimplantation is device failure. Other, less frequent indications consist of "upgrades" (e.g., single to multichannel), infection, and flap breakdown. Although the percentage of failures has decreased over time, an occasional patient requires reimplantation because of device malfunction. The varying designs of internal receiver/stimulators and electrode arrays mandate an examination of the nature and effects of reimplantation for the individual designs. The purpose of the current study was to investigate the reimplantation of several implant designs and to determine whether differences in surgical technique, anatomical findings, and postoperative performance exist. STUDY DESIGN: Retrospective chart review. METHODS: The subjects were 33 of 618 severely to profoundly deaf adults and children who had implantation at the New York University Medical Center (New York, NY) between February 1984 and December 2000. The subjects had previously had implantation with either a single-channel 3M/House (House Ear Institute, Los Angeles, CA) or 3M/Vienna (Technical University of Vienna, Vienna, Austria) device or with one of the multichannel Clarion (Advanced Bionics, Sylmar, CA), Ineraid (Smith & Nephew Richards, TN), or Nucleus (including the Contour) devices (Cochlear Corp., Englewood, CO) before reimplantation. RESULTS: Length of use before reimplantation ranged from 1 month to 13 years and included traumatic and atraumatic (electronic) failures, as well as device extrusion or infection. Results indicated that postoperative performance was either equal to or better than scores before failure. None of the devices explanted caused damage that precluded the implantation of the same or an upgraded device. These findings support the efficacy and safety of internal implant designs as related to the maintenance of a functional cochlea for the purpose of reimplantation. CONCLUSIONS: Cochlear reimplantation can be performed safely and without decrement to performance. The number of implanted electrodes at reinsertion were either the same or greater in all cases.

Performance of multiply handicapped children using cochlear implants.

OBJECTIVE: To explore the possibility of expanding implantation guidelines to include the multiply handicapped population and to determine the pattern of development of perceptual skills in deaf children who have other impairments. PATIENTS AND SETTING: The study group consisted of 31 profoundly deaf children with documented impairments in addition to deafness who were consecutively implanted. Twenty-nine of the children underwent implantation and were followed at NYU Medical Center for at least 1 year. INTERVENTIONS AND MAIN OUTCOME MEASURES: Routine audiometric measurements and closed- and open-set measures of speech perception were performed at the phoneme, word, and sentence level pre- and postoperatively. Analyses of variance were performed when possible. RESULTS: The study population showed substantial improvement after implantation in the ability to perceive phonemes, words, and sentences using audition alone. CONCLUSIONS: Multiply handicapped children obtain demonstrable benefit from cochlear implantation, with no increase in surgical complications, although the rate of growth of perceptual skills is slower than for deaf child with no additional complicating factors.

Shaw scalpel in revision cochlear implant surgery.

The use of traditional electrocautery is prohibited in revision or replacement cochlear implant surgery because of the concern for end organ tissue damage. Additionally, electrical current spread to the malfunctioning device could interfere with an accurate cause-of-failure analysis. Clinical reports have confirmed the utility of the Shaw scalpel for dermatologic, ophthalmic, and head and neck surgery. The Shaw scalpel is a thermally activated cutting blade that provides a bloodless field through immediate capillary and small vessel hemostasis. Avoidance of wound and flap complications is of primary concern in cochlear implant surgery. The long-term wound healing compared favorably to that of other surgical cutting instruments in several experimental reports. We have routinely used the Shaw scalpel in revision cochlear implant surgery and in primary surgery whenever electrocautery was contraindicated. We have retrospectively evaluated 22 cases in which the Shaw scalpel was used for cochlear implant revision and primary surgery. The chart review included patient demographics, the indication for surgery, the contraindication for electrocautery, intraoperative surgical notes, the wound healing evaluation, the evaluation for alopecia, and postoperative speech understanding. No significant complications occurred intraoperatively, and the long-term wound healing results were no different from those obtained with conventional surgical techniques. The explanted devices were undamaged, and valuable diagnostic information could be obtained. All patients performed at or better than their preoperative levels on speech recognition testing. Our results indicate that the Shaw scalpel is a relatively safe, easy-to-use, and effective instrument.

A comparison of the growth of open-set speech perception between the nucleus 22 and nucleus 24 cochlear implant systems.

OBJECTIVE: To compare the short-term development of open-set speech perception between implementations of the spectral peak (SPEAK) strategy in adults using the Nucleus 22 (N22) Spectra processor and the Nucleus 24 (N24) system with the SPrint processor. STUDY DESIGN: Two sets of patients with a follow-up period of 3 months were compared. SETTING: This study was conducted at the New York University (NYU) Medical Center. PATIENTS: Thirty-six profoundly hearing-impaired adults were included in this study. INTERVENTION: Sixteen adults received the N22 cochlear implant with the Spectra speech processor and twenty adults received the N24 cochlear implant with the SPrint speech processor. MAIN OUTCOME MEASURES: Open-set speech perception for the patients with N22 implants was evaluated preoperatively and postoperatively using the following measures: NU-6 monosyllabic words, Iowa sentences, and CID sentences. CNC words, CUNY sentences, and HINT sentences were used to assess the patients with N24 implants. RESULTS: Results revealed that the N22 and N24 cochlear implant recipients had significant open-set speech recognition 3 and 6 months after implantation. The apparent favorable absolute scores for the patients with N24 implants were equalized when a multivariate analysis was performed to account for their younger age at time of implantation and shorter length of deafness. CONCLUSIONS: The growth of open-set word and sentence recognition in similar between the N22 and N24 cochlear implants. Longitudinal studies are needed to determine if higher ceiling scores are present in the N24. Further exploration of monopolar versus bipolar stimulation is warranted.

Implantation of patients with prelingual long-term deafness.

The purpose of this paper is to provide performance data on long-term congenitally and prelingually deafened children and adults who are implanted with the CLARION Multi-Strategy Cochlear Implant and who use the Continuous Interleaved Sampler (CIS) speech processing strategy. Open-set speech perception was assessed preoperatively and postoperatively with word and sentence recognition tests. Results indicate that a majority of subjects showed improvement from preoperative performance to the last available postoperative evaluation. These results represent a change from previously reported data on a similar population who used earlier speech processing strategies.

Early results using the nucleus CI24M in children.

OBJECTIVE: To report early postimplantation speech recognition results in children who received Nucleus CI24M cochlear implants. STUDY DESIGN: The study group consisted of 19 consecutively implanted children. PATIENTS AND SETTING: Congenitally deaf children (20 months to 15 years old) were implanted with the Nucleus CI24M and followed-up at New York University Medical Center for a period of 3 to 12 months. MAIN OUTCOME MEASURES: Speech perception was evaluated preoperatively and postoperatively using the Early Speech Perception (ESP) test, the Glendonald Auditory Screening Procedure (GASP) word and sentence tests, Phonetically Balanced Kindergarten (PBK) monosyllabic word lists, Common Phrases test, the Multisyllabic and Lexical Neighborhood (MLNT, LNT) tests, and the Banford-Kowal-Bench (BKB) sentence test. RESULTS: One-way analyses of variance revealed significant improvement in open-set speech recognition in children able to perform measurement tasks. CONCLUSIONS: The Nucleus CI24M cochlear implant provides significant benefit to children after short-term use.

Stability of the cochlear implant array in children.

OBJECTIVE: To determine cochlear implant electrode stability in the young patient. Electrode migration due to future skull growth was a concern that led to prohibiting implantation in children less than 2 years of age. Recently, the high level of performance achieved by young implantees has led to a re-evaluation of this lower age limit, requiring an assessment of the effects of skull growth over time. STUDY DESIGN: Prospective radiographic analysis of electrode position of cochlear implants in young children. METHODS: Twenty-seven children implanted with the Nucleus (Cochlear Corp., Denver, CO) or Clarion (Advanced Bionics Inc., Sylmar, CA) multi-channel cochlear prostheses were subjects for this study. Follow-up radiographic studies were obtained for a period of 1 month to 5 years after implantation. The age at time of implantation ranged from 14 months to 5 years. An intraoperative modified Stenver's view plain radiograph was obtained as a baseline. After implantation, on a yearly basis transorbital Stenver's and base views were obtained for comparative purposes. Additional radiographs were obtained whenever a change in performance or electrode map caused suspicion for extrusion. Electrode position was determined using a computer graphics enhancement technique whereby image contrast filters enhanced the visibility of the electrode array and surrounding bony structures. RESULTS: An analysis of the data revealed no migration of the electrode array over time. CONCLUSIONS: The confirmation of the stability of the electrode array alleviates the concern of the effects of skull growth on cochlear implantation in young children.

Cochlear implantation in children younger than 2 years old.

OBJECTIVE: To determine the viability of giving implants to children <2 years old and to assess the development of speech perception. STUDY DESIGN: A prospective study with a follow-up period of 1-5 years. SETTING: New York University Medical Center. PATIENTS: The patients consisted of 11 consecutive profoundly deaf children, aged 14-23 months, who were given the Nucleus cochlear implant. METHODS: Closed- and open-set speech perception were assessed preoperatively and postoperatively using the following measures: Early Speech Perception (ESP) test, the Northwestern University children's perception of speech test (NU-CHIPS), the Glendonald auditory screening procedure (GASP) word and sentence tests, the phonetically balanced kindergarten (PBK) word test, common phrases test, the multisyllabic lexical neighborhood test (MLNT), and the lexical neighborhood test (LNT). RESULTS: Paired t test was used to examine changes in scores from the preoperative test interval to the last available postoperative assessment. Results indicate that all patients had significant improvement from preoperative performance to the last postoperative evaluation and were using oral language as their means of communication. There were no medical or surgical complications. CONCLUSIONS: Children <2 years old receive substantial benefit from a multichannel cochlear implant with no increase in risk when compared with older children.

Results of speech processor upgrade in a population of Veterans Affairs cochlear implant recipients.

OBJECTIVE: This study aimed to evaluate the change in performance when the Speak processing strategy replaced the Mpeak strategy. SUBJECTS: Twenty-one veterans who participated in the original Department of Veterans Affairs Multicenter Cochlear Implant Study, received the Nucleus F0F1F2 processor (Cochlear Corp., Englewood, CO, U.S.A.) (WSP) and were subsequently upgraded to the Mpeak (MSP) processing strategy. METHODS: Closed- and open-set speech recognition in quiet and in noise in auditory only conditions at the phoneme, word, and sentence levels were evaluated. RESULTS: Changes in audiologic parameters were evaluated using a paired t-test for related samples. Statistically significant improvements in mean scores were found for all tests and were greatest for the speech-in-noise conditions. An examination of individual data revealed that 61% of the subjects improved for tests administered in quiet, whereas up to 69% of the subjects had improved performance in noise. Subjects with no open set speech discrimination using the Mpeak strategy showed no improvement with the Speak strategy. CONCLUSIONS: Cochlear implants can provide improved performance using modifications to external speech processor hardware and software without changing the internal implant.

Open-set speech perception in congenitally deaf children using cochlear implants.

OBJECTIVE: To assess and document the development of open-set speech recognition in congenitally deaf children implanted with the Nucleus multichannel cochlear prosthesis at < 5 years of age. STUDY DESIGN: The study group consisted of 38 consecutively chosen children in whom the decision to proceed with implantation had already been made. PATIENTS AND SETTING: Congenitally profoundly deaf children were implanted with the Nucleus multichannel cochlear implant at < 5 years of age and followed at NYU Medical Center for a period of 1-5 years. MAIN OUTCOME MEASURES: Open-set speech perception was evaluated preoperatively and postoperatively using the following: the Glendonald Auditory Screening Procedure (GASP) word subset, the GASP sentence subtest, Phonetically Balanced Kindergarten monosyllabic word lists, Common Phrases test, Multisyllabic Lexical Neighborhood test, and Lexical Neighborhood test. RESULTS: Correlation coefficients were calculated between scores at each interval and age at implantation; one-way analyses of variance were performed independently. Results showed that all subjects had significant open-set speech recognition at the time of the last postoperative evaluation. Thirty-seven of the children use oral language as their sole means of communication. CONCLUSIONS: Multichannel cochlear implants provide significant and usable open-set speech perception in congenitally deaf children given implants at < 5 years of age.

Cochlear implantation in children with cochlear malformations.

OBJECTIVE: To address the surgical and habilitative issues raised by cochlear implantation in children with cochlear dysplasia. STUDY DESIGN: The English-language literature is reviewed and the New York University Medical Center experience with three patients is detailed. Two hundred institutions performing cochlear implants were queried by questionnaire. SETTING: Hospitals performing cochlear implantation. PATIENTS: Pediatric patients with a cochlear implant in an ear with a dysplastic cochlea. MAIN OUTCOME MEASURES: Preoperative computed tomography analysis of cochlear anatomy was compared with operative findings, complications, and postoperative device use. RESULTS: Facial nerve anatomy was anomalous in 16% of patients, and there were two surgical injuries. There were no cases of meningitis. All patients who received multichannel implants derive benefit and wear their devices. CONCLUSIONS: All degrees of cochlear dysplasia, ranging from incomplete partition to common cavity, can be safely implanted and auditory responses expected.

Postoperative imaging of the multichannel cochlear implant.

PURPOSE: To present the postoperative radiographic appearance of the multichannel cochlear implant and to suggest criteria for the radiographic evaluation of postimplant patients. METHODS: One hundred forty-one patients, 73 female and 68 male, had multichannel cochlear implants inserted. One hundred thirty-five intraoperative radiographs, 31 postoperative radiographic examinations, and 10 postoperative CT examinations were retrospectively reviewed. RESULTS: In 135 patients, a Stenver's or anteroposterior projection confirmed the normal placement of the implant by demonstrating the electrodes to be regularly spaced and gently curved within the first turn of the cochlea. The insertion depth was determined by counting the number of electrodes that projected medial to the cochlear promontory. In 5 patients in whom intracochlear placement of the electrode array could not be confirmed on plain radiographs, CT demonstrated the location of the electrode array. In 3 patients with postoperative infections, CT either correctly identified or excluded the presence of a collection beneath the implant. CONCLUSION: Plain radiographs of the temporal bone are sufficient for the postoperative treatment of the majority of postimplant patients. CT should be performed when plain radiographs cannot adequately show the location of the electrode array or if postoperative infection is suspected.

Predictors of postoperative performance with cochlear implants.

One objective of the Department of Veterans Affairs study: A Prospective Randomized Study of Advanced Cochlear Implants was to attempt to identify preoperative patient characteristics that might predict postoperative performance. We studied the relationship between all preoperative factors and the 2-year postoperative performance on 24 audiological tests for 82 patients who were implanted with the Ineraid, Nucleus, or 3M/Vienna device. Results of the univariate analysis indicated that computed tomographic findings of the cochlea and round window, IQ, age at implantation, length of deafness, profound deafness, and lipreading ability weakly correlated to postoperative performance. The multivariate analysis showed age at time of implantation, IQ, and lipreading ability to be predictive of postoperative performance.

Performance as a function of time: a study of three cochlear implant devices.

This study examines the relationship of time to cochlear implant patient performance and the effect of device design on patient performance over time. Data were collected for patients who were implanted with Nucleus 22, Smith & Nephew Richards Ineraid, or 3M/Vienna cochlear implants as part of the Veterans Administration study on cochlear implants. Patients were administered a comprehensive audiological test battery prior to implantation, at stimulation, and 3 months, 1 year, and 2 years poststimulation. Results show that patient performance improved over the course of the study, with performance levels with each multichannel implant being similar at the study end point. The Nucleus device produced maximum performance sooner than the Ineraid device did, and performance of the single-channel 3M was consistently below that of the multichannel devices.

Influence of processing strategies on cochlear implant performance.

The development of new processing strategies has allowed for the improvement of auditory skills in cochlear implant recipients. This study examines the effects of a change in processing strategy on the individual recipients of the Nucleus cochlear prosthesis. Twenty-five subjects who had used the F0F1F2 processing strategy (WSP III) for 2 years were switched to the MPeak strategy (MSP) and retested immediately and after 3 months. Results revealed an improvement in speech recognition ability with the MPeak strategy in those subjects who were able to perceive speech with the F0F1F2 processing strategy.

Long-term results of early cochlear implantation in congenitally and prelingually deafened children.

Cochlear implants have been shown to improve the speech perception and production skills in children. Data are available on congenitally and prelingually deafened children who were implanted at an older age, but data on children implanted below the age of 3 years are scarce. The present study examines the benefits obtained with early implantation of the young deaf child. Fourteen congenitally or prelingually profoundly hearing-impaired children were implanted before the age of 3 years, with the Nucleus multichannel cochlear prosthesis, and followed for 2-5 years. Results indicate an overall improvement in the perception of all aspects of the speech signal in the auditory-only condition with the cochlear implant. All the children use oral language as their primary mode of communication and attend regular schools. Based on the results of this investigation, the authors conclude that implantation of the young deaf child is beneficial to the development of auditory perceptual skills.