Otology & Neurotology25:504–510 © 2004, Otology & Neurotology, Inc.              Revision Cochlear Implant Surgery in Adul...
REVISION COCHLEAR IMPLANTATION                                                       505plantation for suspected device ma...
506                                                        C. A. BUCHMAN ET AL.TABLE 1. Symptoms and signs prompting revis...
REVISION COCHLEAR IMPLANTATION                                                                   507                      ...
508                                              C. A. BUCHMAN ET AL.                                                     ...
REVISION COCHLEAR IMPLANTATION                                                         509substrate were identified. The c...
510                                                    C. A. BUCHMAN ET AL. 9. Saeed SR, Ramsden RT, Hartley C, et al. Coc...
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  1. 1. Otology & Neurotology25:504–510 © 2004, Otology & Neurotology, Inc. Revision Cochlear Implant Surgery in Adult Patients with Suspected Device Malfunction Craig A. Buchman, Carol A. Higgins, Robert Cullen, and Harold C. Pillsbury Department of Otolaryngology–Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, U.S.A.Objective: To report the outcomes of patients that have aversive auditory (n 23 [92%]) or nonauditory (n 21undergone revision cochlear implant surgery for suspected de- [84%]) symptoms or performance-related issues (n 16vice malfunction. [64%]) while maintaining a lock (i.e., suspected soft failure).Study Design: Retrospective case series. Revision surgery resulted in resolution of the patient’s pre-Setting: Academic medical center. senting signs and symptoms in nearly 90% of cases and sig-Patients: Adult cochlear implant patients with devices that fail nificant improvements in auditory performance. Perioperativeto lock or maintain a lock but are associated with troubling complications were uncommon. Preoperative testing and de-signs and symptoms. vice analysis frequently did not reveal the reason for presumedIntervention: Revision cochlear implant surgery. device malfunction.Main Outcome Measures: Demographics, presenting signs Conclusion: Revision cochlear implantation should be consid-and symptoms, surgical findings, complications, audiologic ered in patients significantly affected by intolerable auditoryperformance and device analysis. and/or nonauditory symptoms or when performance issuesResults: To date, 33 revision cochlear implant operations have have been documented. Key words: Cochlear implant—been performed in 30 patients. Eight (24%) presented with a Performance—Reimplantation—Revision surgery.failure of the speech processor to lock with the internal device(i.e., hard failure). Twenty-five (76%) presented with either Otol Neurotol 25:504–510, 2004. The benefits of cochlear implantation for patients with patient (i.e., hard failure), the decision to undertake re-severe to profound sensorineural hearing loss are signifi- vision cochlear implantation is a relatively simple onecant and include improved sound awareness, enhanced (2). Substantially more difficult are the patients that de-lip reading, and speech understanding. Although most velop complaints while having a seemingly functioningpatients’ cochlear implants provide safe and reliable au- device (i.e., suspected soft failure). These cases present aditory benefit, occasionally patients develop problems number of particular challenges for both the otologistthat require revision surgery. Surgical complications that and the audiologist responsible for evaluating and man-oftentimes necessitate revision surgery include skin flap aging these patients.breakdown, wound infection, device extrusion, and oc- The present study was undertaken to review one cen-casionally electrode malposition (1). In most cases, these ter’s experience with revision cochlear implantation.problems are readily apparent and revision surgery is This study is unique in that a number of revision casesundertaken as a medical necessity. were performed in patients with cochlear implants that Patients with cochlear implants may also present with still provided some auditory information. Presentingcomplaints of decreased auditory performance or the signs and symptoms that were indicative of a successfulnew development of other troubling auditory (e.g., tin- revision implant surgery were sought.nitus) or nonauditory (e.g., pain) symptoms. For patientsin whom the device provides no auditory input to the MATERIALS AND METHODS Address correspondence and reprint requests to Craig A. Buchman,M.D., Department of Otolaryngology–Head and Neck Surgery, 610 PatientsBurnett-Womack Building (CB# 7070), University of North Carolina at Approximately 600 patients have undergone cochlear im-Chapel Hill, Chapel Hill, NC 27599-7070, U.S.A.; Email: buchman@ plantation at our institution since 1992. During this time period,med.unc.edu 224 adults have undergone implantation. Of these, 30 (13%) Presented, in part, at the Combined American Neurotology Society– patients have had revision surgery consisting of either cochlearTriological Society Forum, May 4, 2003, Nashville, Tennessee, U.S.A. explantation with or without reimplantation or contralateral im- 504
  2. 2. REVISION COCHLEAR IMPLANTATION 505plantation for suspected device malfunction. A retrospective Surgical findings, postoperative complications,review of these patients’ records was undertaken for preopera- and device analysistive and postoperative signs and symptoms, audiologic testing The medical records were also reviewed for surgical findingsdata, radiographic analysis, surgical findings, postoperative as well as intraoperative and postoperative complications. De-complications, and device analysis. An emphasis was placed on vice information including model, dates of initial and revisionidentifying signs and symptoms that could be helpful in pre- surgery, as well as the device analysis results were obtaineddicting benefit from revision cochlear implantation. This study from the medical records and cross-checked against each of thewas approved by the institutional review board. manufacturers’ databases for accuracy. Data Statistical analysis Data were both categorical (symptoms and signs, cochlear implant devices, CNC word score performance categories, and Signs and symptoms complications) and continuous (CNC word scores and duration Presenting symptoms were classified as either auditory or of device use). For the categorical data, frequency respondersnonauditory. Auditory symptoms included a subjective de- were calculated and significance testing performed using the 2crease in performance; a lack of sound perception; and the test when appropriate. For the continuous data, means and stan-development of severe, incapacitating tinnitus or sound hyper- dard deviations were computed. Significance testing was car-sensitivity. New-onset tinnitus that was significantly different ried out using one-way analysis of variance (ANOVA). Pair-in quality and severity from normal tinnitus was termed “atypi- wise comparisons were then performed if p < 0.05 using Tukeycal tinnitus.” Atypical tinnitus was described in a variety of post hoc testing procedures to identify where the differencesways, including thumping, engine-like noise, airplane sounds, occurred. For performance data, between-device comparisonsclicks, pops, and sirens. Nonauditory symptoms consisted of were not undertaken because of differing durations of hearingpain over the device, shocking sensations, vertigo, and facial loss and device usefulness as well as the fact that devices weretwitching. The relationship of the symptoms to sound and the replaced for expected malfunction. For those patients that un-use of the device were also sought. Signs were classified as derwent more than one revision surgery, the most recent scoresbeing either performance-related or a failure to lock. Failure to were used in calculating group means.lock referred to either complete absence of auditory percepts bythe patients or when the internal device failed to communicatewith the external device. Performance-related signs that were RESULTSconsidered to be indicative of a possible device malfunctionincluded either postoperative performance with the patient’sfirst cochlear implant that was worse than their preoperative Thirty-three revision surgeries were performed in 30performance or when a substantial decrease in performance patients during the time period of the study. Twenty-fivewas documented from their previous levels. Resolution of the (83%) of 30 patients underwent initial cochlear implantsigns and symptoms that prompted revision surgery was surgery at our institution. Of the 33 procedures, 3 pa-also sought. tients had contralateral cochlear implantation, 1 main- taining the initial device and 2 having the initial device Audiologic testing removed. The remaining 30 operations were performed Objective measures of hearing are routinely sought on in 27 patients. One patient had their cochlear implantall patients that undergo cochlear implantation at our in- removed without replacement, 3 patients had two revi-stitution. Speech perception testing may include both mea- sion surgical procedures on the same ear, and 23 had asures of word recognition (CNC) and sentence recognition in single operation consisting of device removal with re-both quiet (CID, CUNY, HINT) and noisy conditions (HINT placement in the same ear.+10 dB signal-to-noise ratio, HINT +5 dB signal-to-noise ra- The mean age at presentation for initial revision sur-tio). For the purposes of the current study, CNC monosyllable gery was 50 ± 20 years. The mean duration of hearingword list scores were used to describe auditory perception abili- loss was 15 ± 14 years and the mean duration of firstties (3). implant use was 3 ± 4 years (range, 0.2–14 yr). Of the CNC word scores were presented using 50 test-word listsfrom a commercially available compact disk (1996 Version) three patients with more than one revision, the meandeveloped by the House Ear Institute (Los Angeles, CA, duration of second implant use was 3 ± 4 years. ThereU.S.A.). CNC word scores are reported as a scaled score were nine (30%) patients that were prelingual at the timefrom 0 to 100% correct. Scores were available before and of initial implantation, and the cause of hearing loss wasafter revision surgery at 1, 3, 6, 12, 24, and 36 months considered to be viral (n 2 [7%]), meningitis (n 2for varying numbers of patients. The purpose of the current [7%]), otosclerosis (n 2 [7%]), ototoxicity (n 2study was to determine whether changes in auditory perception [7%]), Ménière’s disease (n 1 [3%]), Waardenburgabilities occurred after revision surgery. Because there were syndrome (n 1 [3%]), hereditary (n 1 [3%]), Rh-varying degrees of performance before implantation, the pre- incompatibility (n 1 [3%]), head trauma (n 1operative CNC word score was subtracted from the individual [3%]), or unknown (n 17 [57%]).score at the various testing times after surgery. For the purposesof the current study, an increase in CNC word score of greaterthan 15% was considered improved performance and a de- Presenting symptoms and signscrease in score of greater than 15% was considered worse per- Signs and symptoms prompting evaluation and reim-formance. Changes in score of ±14% were considered un- plantation for the 33 operations are shown in Table 1. Achanged (4). number of patients had more than one reason for reim- Otology & Neurotology, Vol. 25, No. 4, 2004
  3. 3. 506 C. A. BUCHMAN ET AL.TABLE 1. Symptoms and signs prompting revision surgery wound hematoma that resolved spontaneously, three by locka (9%) patients had transient vertigo and imbalance, three Lock intact (n 25) (9%) patients complained of transient taste disturbance, and one (3%) patient developed a tympanic membrane Preoperative Postoperative perforation requiring tympanoplasty for resolution. (%) (%) p valueSymptoms Auditory 23/25 (92) 3/25 (12) <0.001 Resolution of symptoms and signs Nonauditory 21/25 (84) 2/25 (8) <0.001 For revision surgery in which the processor main-Signs tained a lock with the internal receiver/stimulator, aver- Performance issues 16/25 (64)b See performance data sive auditory symptoms resolved in 20 (87%) of 23 af- Facial stimulation 2/25 (8) 1/25 (4) NSTechnology update 12/25 (48)b fected patients and nonauditory symptoms resolved in 19Failure to lock 8/33 (24) (91%) of 21 affected patients. These improvements were a statistically significant (p < 0.001). The cause of aversive Failure to lock refers to either complete absence of auditory per- nonauditory symptoms (i.e., pain) appeared related to acepts by the patients or when the internal device failed to communicatewith the external device (i.e., hard failure). misplaced extracochlear reference electrode in the ster- b Does not include failure to lock. nocleidomastoid muscle in one case. Moreover, one of NS, not significant. two patients with preoperative facial stimulation and pain had symptom resolution after surgery as a result of removing a partially extruded electrode and device andplantation. Eight (24%) operations were performed for replacing it with a completely inserted device. The othera failure to lock and were considered a hard failure. patient with facial stimulation continued to have thisOf these eight patients, two (25%) had head trauma problem postoperatively. Two patients with both audi-before device failure, two (25%) were poor performers tory and nonauditory symptoms failed to improve afterfrom initial stimulation, and one (13%) patient noted a surgery. One of these patients had the device removeddecrement in performance over time that was docu- with persistent symptoms. Another patient with preop-mented on audiometric testing. The remaining patient’s erative auditory symptoms had contralateral implantationspeech processors maintained a lock with the internal without device removal because they wanted to keep thereceiver/stimulator. functioning device. Twenty-five (76%) of 33 operations were undertakenfor suspected device-related problems despite maintain-ing a lock (i.e., suspected soft failure). Nearly all of these Cochlear implant devicespatients complained of significant aversive auditory Table 2 lists the various cochlear implants and the(92%) and/or nonauditory symptoms (84%) before ex- duration of device use before explantation for all opera-plantation (see above, under Materials and Methods). At tions and those initially performed at our institution. Ofleast 20 (80%) of 25 patients had atypical tinnitus as one the 33 revision operations, 32 had a replacement deviceof their auditory symptoms. Moreover, 64% also had inserted and 1 patient elected to have the device removedauditory performance related issues (see above, under without reinsertion. There were statistically significantMaterials and Methods). Facial stimulation was present differences in the proportion of revision opeartions un-in two (8%) patients. dertaken by device manufacturer. Med-El Corp. (Inns- bruck, Austria) had significantly fewer devices removed Surgical procedure than both Cochlear (Sydney, Australia) and Advanced Revision surgery was generally uncomplicated. Five Bionics Corp. (Sylmar, CA, U.S.A.) (p < 0.003), al-(15%) patients required significant revision of the mas- though there was no difference in the proportion of de-toidectomy as new bone growth had occurred. At sur- vices removed between Cochlear and Advanced Bionics.gery, one (3%) patient was identified with an extraco- The duration of implant use before removal was alsochlear reference electrode that was in the region of the different among the various device manufacturers (psternocleidomastoid muscle and another patient (3%) 0.005), with the Cochlear devices having longer durationhad a partial electrode array extrusion from the cochlea. of use before revision than both the Med-El and Ad-The electrode was replaced in the same cochleostomy in vanced Bionics devices. Individual device comparisonsall but four cases, where contralateral implantation was showed a significantly shorter duration of use beforeundertaken (n 3) or the device was not replaced (n revision for both the Advanced Bionics Clarion 1.2 with1). There was one intraoperative cerebrospinal fluid leak HiFocus and Clarion 1.2 with Spiral when compared(3%) through the cochleostomy that was controlled with with the Cochlear Nucleus 22 device. The other devicepacking. There were no facial nerve complications. The comparisons showed no significant differences. A calcu-removed device was usually placed in a device explant lation of the cumulative survival percentages was notkit from the manufacturer and returned. possible because many patients that had previously un- Postoperatively, there were no serious complications dergone implantation in our program had moved else-such as facial paralysis, cerebrospinal fluid leak, wound where and been lost to follow-up, and a number of pa-infections, or death. One (3%) patient did develop a tients that had not initially undergone implantation in ourOtology & Neurotology, Vol. 25, No. 4, 2004
  4. 4. REVISION COCHLEAR IMPLANTATION 507 TABLE 2. Cochlear implants Total Local Replacement Device revisionsa (%) Durationb (yr) revisionsc (%) (%) TotalAdvanced Bionics Corp. (Sylmar, CA, USA) Clarion 1.2 with Spiral 11 (17) 2.5 ± 1.2 9 (13) 6 (9) 69 Clarion 1.2 with HiFocus ± EPS 11 (42) 1.3 ± 1.0 11 (42) 1 (4) 26 Clarion CII 0 (0) 0 (0) 2 (100) 2 Total 22 (23) 1.9 ± 2.8 20 (20) 9 (9) 98Cochlear Corp. (Sydney, Australia) Nucleus 22 9 (28) 7.4 ± 4.1 6 (21) 2 (7) 30 Nucleus 24 0 (0) 0 (0) 5 (29) 17 Total 9 (20) 7.4 ± 4.1 6 (13) 7 (15) 46Med-El Corp. (Innsbruck, Austria) Combi 40+ 2 (<1) 1.1 ± 0.5 1 (<1) 16 (20) 80 Total 2 (<1) 1.1 ± 0.5 1 (<1) 16 (20) 80Overall totals 33 (15) 3.4 ± 3.4 24 (11) 32 (14) 224 a Represents the device in place before revision as a proportion of all adult cochlear implant operations at our institution. b Represents mean ± SD time between first implant and revision. c Represents only those devices implanted at our institution that underwent revision as a proportion of all adult cochlear implant operations at ourinstitution. EPS, electrode positioning system.program underwent revision surgery. When those cases follow-up. Revision implant surgery resulted in substan-with their initial implantation performed elsewhere were tial improvements in CNC word scores early in the post-removed (Clarion 1.2 with Spiral, n 3; and Nucleus operative period. These improvements continue to date.22, n 2), similar results were found. Repeated measures ANOVA demonstrated significant Table 3 shows the device analysis findings of the improvements (p < 0.001) in mean CNC word scoresmanufacturers by mode of failure. Six of eight devices over the entire postoperative period. Post hoc testingwith a failure to lock were confirmed as device failures showed significant improvements at each of the postop-by the manufacturers and one device was lost and never erative periods when compared with baseline except foranalyzed; the status of one device is unknown. Of the 25 the 1-month interval (all p < 0.05).revision operations performed on patients with a device To ensure that the observed statistical changes inthat maintained lock, 24 were received by the manufac- speech perception were not solely related to improve-turer and one patient’s device was not removed. Five ments by those patients with a failure to lock, the analy-(21%) of 24 had demonstrated abnormalities on analysis, sis was repeated, omitting those patients with hard fail-18 (75%) were identified as normal or no failure mode ures. Fifteen patients had available data. ANOVA testingfound, and 1 (3%) analysis is pending. again demonstrated significant improvements (p < 0.001) in mean CNC word scores over the entire postoperative Performance period. Post hoc testing showed significant improve- CNC word scores were available for 20 patients before ments at each of the postoperative periods when com-their most recent operation. At 1-, 3-, 6-, 12-, 24-, and pared with baseline except for the 1- and 3-month inter-36-month follow-up visits, the number of patients that vals (all p < 0.05).had data available were 20, 16, 13, 13, 8, and 1, respec-tively. Those 10 patients without available performancedata before and after surgery were either opposite earimplantations (n 3), no device reimplanted (n 1),dead (n 1), or prelingual (n 5) and unable to per-form the CNC word test. Figures 1 and 2 show postop-erative changes in CNC word scores as a function of TABLE 3. Device analysis Lock intact Fail to lock Analysis findings (n 24) (n 8)Normal/unknown 18 2Shift in voltage-controlled oscillator 1 0Chip failure 0 1Broken substrate 1 0Broken wires 2 0 FIG. 1. Changes in CNC word score by postoperative month.Hermeticity (leak) failure 1 5 Better is defined as a 15% or greater increase in score. Same isPending 1 0 defined as a ±14% change in score. Worse is define as a 15% or greater reduction in score (4). Otology & Neurotology, Vol. 25, No. 4, 2004
  5. 5. 508 C. A. BUCHMAN ET AL. performance before device failure, suggesting that some degree of device malfunction may have started before the failure to lock. Nearly all of the device analyses for these explanted devices revealed problems consistent with a failure to lock and function. For those patients undergoing revision surgery when the device maintained a lock with the internal receiv- er/stimulator, aversive symptoms and signs were re- solved in approximately 90% of cases. Moreover, significant early improvements in auditory perception abilities were demonstrated for those individuals with available CNC word score data. As early as 3 monthsFIG. 2. CNC word scores with the original device versus thereplacement device. Squares represent 6-month data (n = 13) after surgery, 50% of patients with available data hadand diamonds represent 1-year data (n = 13). better performance than with their previous cochlear im- plant, and after 12 months of use, 69% of patients with available data had better performance than with their DISCUSSION previous implant. These findings substantiate the fact that some patient’s with an apparently functioning co- Cochlear implants are highly effective for treating pa- chlear implant can have displeasing symptoms and/ortients with severe to profound sensorineural hearing loss. signs that may be related to problems with either theOccasionally, however, the cochlear implant does not device’s location or function. Unfortunately, availableprovide the intended benefit or is associated with symp- testing methodologies such as radiographic imaging andtoms and signs that are significantly displeasing to the device integrity testing were usually unable to identifypatient. Although the reasons for these outcomes are those patients that would benefit from such intervention.complex and not always obvious, implant teams are left Although the overall revision operation rate (11%) into decide which patients should be offered revision surgery. the present series is consistent with those previously re- At our center, patients have presented with a wide ported by other large centers, the number of hard failuresvariety of signs and symptoms that they felt were unac- (4%) that were operated on in the current study is com-ceptable. For patients with a nonfunctioning device (i.e., paratively quite low (2,5–11). We believe that this isfailure to lock or failure to provide any auditory infor- because our center performs revision surgery on moremation), reimplantation was undertaken. The decision to patients with devices that maintain a lock. The excellentoffer patients reimplantation when their cochlear implant outcomes documented in this study support the premisewas providing some auditory information was complex. that the previously detailed management scheme suc-These patients frequently underwent numerous testing cessfully identifies those patients with dysfunctional co-procedures including device integrity testing, radio- chlear implants before the onset of hard failure.graphic evaluation, and audiologic testing. Before under- The reason or reasons why revision cochlear implanttaking revision surgery, external equipment was usually surgery is effective for patients with displeasing symp-changed out and reprogramming attempted to see wheth- toms and signs may be related to many factors. Presum-er signs and/or symptoms would abate. Subsequently, all ably, symptoms can result from a normally functioningpatients were counseled that reimplantation could carry device that interacts with the patient in an adverse waywith it, in addition to the normal risks of cochlear im- because of abnormal location. This occurred in at leastplant surgery, the possibility of decreased auditory per- two of our patients. One patient had an extruding elec-formance (3). Moreover, all patients were counseled that trode array into the middle ear that resulted in substantialthose symptoms that were not attributable to the device facial stimulation and pain that could not be alleviatedfunction or location may not be improved after surgery. with changes in programming. Another patient had aThe decision to undergo revision implantation in these misplaced extracochlear reference electrode in the regionpatients was made by the patient and the cochlear im- of the sternocleidomastoid muscle that resulted in upperplant team members. Generally, when unacceptable neck pain in the region. In both cases, revision surgerysymptoms were present, ipsilateral revision was under- resulted in complete resolution of the symptoms and thetaken. When the patient was more concerned with device device analyses were normal.performance, contralateral implantation was considered. Another potential cause of aversive symptoms and The present study details the results of the above- signs in patients with a cochlear implant that maintainsmentioned management scheme. Of the 33 operations lock is that the device is malfunctioning (i.e., soft fail-undertaken, 24% were undertaken for a failure to lock. ure). In at least five cases in the current study, patientsAs expected, reimplantation in these patients resulted in underwent uneventful surgery, their symptoms com-substantial improvements in auditory abilities. These pletely resolved postoperatively, and device analysisfindings are consistent with those reported by numerous confirmed a technical problem with the implant. Prob-other implant teams (2,5–11). Interestingly, at least one lems such as broken wires, voltage-controlled oscillatorpatient in this category had a slow decrement in auditory shift, hermeticity failure (i.e., case leak), and a brokenOtology & Neurotology, Vol. 25, No. 4, 2004
  6. 6. REVISION COCHLEAR IMPLANTATION 509substrate were identified. The causes for many of these The retrospective nature of the investigation makes theidentified abnormalities remain obscure. Likewise, the gathering of information contained in this study difficult.causal relationship between these findings and the pa- Because there were no standardized instruments for as-tient’s symptoms, signs, and performance is also specu- sessing signs and symptoms in these patients, the medi-lative. In fact, the relative frequency of these various cal record was used to assess these variables. The lack ofdevice abnormalities in the general cochlear implant a control group also makes interpretation somewhat dif-population is unknown. Postmortem analysis of devices ficult. For instance, what is the frequency of auditory andthat were functioning before death may help answer this nonauditory symptoms in the general cochlear implantquestion. Nevertheless, these findings suggest that de- population? Is atypical tinnitus (thumping, engine-likevices with identified structural defects may retain the noise, airplane sounds, clicks, pops, and sirens) commonability to function in some capacity while possibly caus- among other implant patients? A significant number ofing aversive symptoms to the patient. Another group of the patients in this report were prelingual. This popula-patients consisted of those that underwent successful re- tion may have significant problems relating their symp-vision surgery where no surgical reason for the patient’s toms as well as having a frame of reference on which tosymptoms was identified and the device analysis was base their complaints.returned as normal. In the current study, this constitutedthe largest group of patients. In these cases, the truecause for successful revision surgery remains elusive. CONCLUSIONSPossibilities include either device-related issues or pa-tient-related issues. Because all of these cases were un- Cochlear implants are highly effective and reliable atcomplicated removal and replacements, undetected de- providing speech understanding for patients. The currentvice defects are suspected. Nevertheless, this remains an study demonstrates that these devices can sometimes failunresolved issue. Perhaps better device testing protocols to provide the intended benefit or can occasionally resultwill help resolve this troubling dilemma. in aversive auditory or nonauditory symptoms or perfor- Caution should be exercised when trying to use the mance-related issues that prompt the patient to have theresults of the current study to identify differences among device removed. In these highly selected cases, cochlearthe various implant manufacturers with regard to device implant replacement is highly effective at restoring au-reliability and performance. Numerous publications ditory input as well as relieving displeasing symptoms.stress the need for cumulative survival percentages as the Preoperative testing usually is unable to identify thoseonly way to report device reliability statistics. Cumula- patients that would benefit from revision surgery. Intive survival percentages could not be computed between some cases, postremoval device analysis by the manu-the three device manufacturers in our study because of facturer reveals abnormalities and other times is unre-loss of patient follow-up as well as performing revision vealing. Currently, we offer revision cochlear implantoperations on patients that had initially undergone im- surgery to patients with severe, aversive symptoms andplantation elsewhere. Relatively small numbers may also signs or performance-related issues that are unacceptableresult in significant power problems for making these to the patient. Possibly, future developments in devicecomparisons. The findings of this study should prompt assessment technology may allow better identification ofthe various cochlear implant manufacturers to reassess these patients before undertaking revision surgery.their reporting criteria for device failures. Specifically,revision cochlear implant operations that result in sig-nificant improvements in patient symptoms, signs, and REFERENCESauditory abilities should be closely monitored. When de-vice analysis reveals abnormalities, consideration should 1. Hoffman RA, Cohen NL. Complications of cochlear implant sur-be given to including these findings in the reported cu- gery. Ann Otol Rhinol Laryngol Suppl 1995;166:420–2.mulative survival percentages. When device analysis 2. Henson AM, Slattery WH III, Luxford WM, et al. Cochlear im-fails to reveal the cause, a detailed analysis of all device- plant performance after reimplantation: a multicenter study. Am J Otol 1999;20:56–64.handling procedures is needed. 3. Luxford WM. Minimum speech test battery for postlingually deaf- It is worth mentioning that cochlear implant device ened adult cochlear implant patients. Otolaryngol Head Neck Surganalysis appears to be an evolving process. In the current 2001;124:125–6.study, a number of devices initially identified by the 4. Olsen WO, Matkin ND. Speech audiometry. In: Rintelman WF, ed.manufacturer as having abnormalities were later reclas- Hearing Assessment. 2nd ed. Austin, TX: Pro.ed, 1991:39–140.sified as normal. Thus, the significance of these identi- 5. Balkany TJ, Hodges AV, Gomez-Marin O, et al. Cochlear reim-fied abnormalities remains unknown. As these changes plantation. Laryngoscope 1999;109:351–5.may have resulted from manufacturing, implantation, 6. Hamzavi J, Baumgartner WD, Pok SM. Does cochlear reimplan- tation affect speech recognition? Int J Audiol 2002;41:151–6.trauma, explantation procedures, or postremoval pro- 7. Parisier SC, Chute PM, Popp AL, et al. Outcome analysis of co-cessing, improved device testing methods both in situ chlear implant reimplantation in children. Laryngoscope 2001;111:and after removal should allow for a more accurate as- 26–32.sessment of the causal relationships. 8. Woolford TJ, Saeed SR, Boyd P, et al. Cochlear reimplantation. The shortcomings of the current study are noteworthy. Ann Otol Rhinol Laryngol Suppl 1995;166:449–53. Otology & Neurotology, Vol. 25, No. 4, 2004
  7. 7. 510 C. A. BUCHMAN ET AL. 9. Saeed SR, Ramsden RT, Hartley C, et al. Cochlear reimplantation. that the device was functioning normally. The proof was J Laryngol Otol 1995;109:980–5. in the outcomes: 90% of “soft failure” cases showed10. Alexiades G, Roland JT Jr, Fishman AJ, et al. Cochlear reimplan- tation: surgical techniques and functional results. Laryngoscope resolution of aversive symptoms and improved hearing 2001;111:1608–13. after reimplantation. The take-home message: electrical11. Miyamoto RT, Svirsky MA, Myres WA, et al. Cochlear implant testing cannot rule out device failure. The authors are to reimplantation. Am J Otol 1997;18(6 Suppl):S60–1. be congratulated for moving the field forward. INVITED COMMENT Thomas Balkany Department of Otolaryngology This series demonstrates safety and improved hearing University of Miami Ear Instituteoutcomes to be expected when removing and replacing Universit of Miami School of Medicinean implant. Nonetheless, this study and others showing Miama, Floridaoverall reimplant benefit (1,2) remind us that some pa-tients will do worse with the secondary device and somewill have complications. REFERENCES More importantly, this study breaks new ground in 1. Balkany TJ, Hodges AV, Gomez-Marin O, et al. Cochlear implan-recognizing and managing so-called “soft failures.” Fully tation. Laryngoscope 1999;109:351–355.75% of the failures occurred in the absence of “hard” 2. Alexiades G, Roland JT, Fishman AJ, et al. Cochlear reimplanta-(electronic) findings. Thus, the patients and audiologist tion: surgical techniques and functional results. Laryngoscope 2001;knew something was wrong, but were told in many cases 111:1608–1614.Otology & Neurotology, Vol. 25, No. 4, 2004