Otology & Neurotology 36:944Y952 Ó 2015, Otology & Neurotology, Inc.
Pros and Cons of Round Window Vibroplasty in Open Cavities: Audiological, Surgical, and Quality of Life Outcomes Luis Lassaletta, Miryam Calvino, Isabel Sa´nchez-Cuadrado, Rosa M. Pe´rez-Mora, Elena Mun˜oz, and Javier Gavila´n Department of Otolaryngology, ‘‘La Paz’’ University Hospital, IdiPAZ, Madrid, Spain
Objective: To evaluate the audiological, surgical, quality of life, and quality of sound outcomes in adults with open cavities implanted with the Vibrant Soundbridge (VSB) implant using round window (RW) vibroplasty approach. Study Design: Retrospective study. Setting: Otolaryngology department, tertiary referral hospital. Subjects and Methods: Twelve adult patients with conductive or mixed hearing loss, all with previous middle ear surgery, underwent RW vibroplasty in an open cavity. Compound action potential thresholds were assessed during surgery. Surgical complications were recorded. Subjective benefit was evaluated using the Nijmegen Cochlear Implant Questionnaire (NCIQ), Glasgow Benefit Inventory (GBI), and Hearing Implant Sound Quality Index (HISQUI29) tests. Results: Mean follow-up was 42 months (range 12Y76). There was no significant change in bone conduction thresholds after surgery. Mean functional gain was 34.3 dB and speech dis-
crimination score at 65 dB significantly improved from 14 to 83%. Extrusion of the wire link was the main surgical complication in four patients. All NCIQ domains improved after surgery. All patients had a positive overall GBI score (mean 35.0). Mean HISQUI29 score was 152.8, on average the quality of sound being defined as ‘‘very good.’’ Conclusion: VSB is an effective method of hearing restoration for adults with open cavities suffering from conductive or mixed hearing loss. Intraoperative electrocochleography may be considered of significant help to check the coupling to the inner ear. The high rate of extrusion suggests that middle ear obliteration may be considered in these patients. Key Words: ComplicationsV Conductive hearing lossVElectrocochleographyVMixed hearing lossVQuality of lifeVQuality of soundVRound windowV Subjective questionnairesVVibrant SoundbridgeVVibroplastyV Wire extrusion. Otol Neurotol 36:944Y952, 2015.
Restoration of hearing in patients with open cavities is a matter of controversy. Most patients suffer from conductive or mixed hearing loss, and treatment options include reconstructive middle ear surgery, conventional hearing aids, bone conduction implants, and middle ear implants (1). The Vibrant Soundbridge (VSB; MED-EL, Innsbruck, Austria) is an active middle ear implant device aiming to compensate for moderate-to-severe, ski-slope sensorineural (SNHL), mixed and conductive hearing losses. The VSB delivers vibratory energy to a vibratory structure of the middle ear via the floating mass transducer (FMT). For SNHL, the FMT is attached to the long process of the incus, whereas in cases where the ossicular chain is missing, interrupted, or malformed, the FMT can stimulate the cochlea directly via the round window (RW)
membrane or via the stapes superstructure, bypassing the external auditory canal (EAC) and middle ear. The mechanical stimulation of the inner ear may be considered for patients suffering from chronic diseases with previously unsuccessful reconstruction surgeries. Since the first study about direct RW stimulation with the VSB by Colletti (2), several articles have been published on the treatment of patients with chronic ear and mixed or conductive hearing loss (3Y8). Currently, the RW niche technique, termed as RW vibroplasty, is the most frequent application for patients with conductive or mixed hearing loss. The advantage of the FMT on the RW membrane is assumed because the middle ear is bypassed, being the effective point of vibration beyond the site of pathologic findings, and thus, the amplification provided by the VSB should be totally available for inner ear stimulation. Although most studies show remarkable audiological improvement with VSB vibroplasty, some aspects still remain controversial: (a) the lack of a systematic approach to patients with open cavities after RW vibroplasty
Address correspondence and reprint requests to Luis Lassaletta, M.D., Department of Otolaryngology, IdiPAZ, Hospital La Paz, Paseo de la Castellana, 261, 28046 Madrid, Spain; E-mail: [email protected] The authors disclose no conflicts of interest.
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x x x x x x x
x
x x
x
x x
x x
x x x x x x x
x x
F/38 M/61 F/64 M/42 M/47 F/36 M/62 F/34 M/41 F/77 M/24 F/70 49.7 16.6 1 2 3 4 5 6 7 8 9 10 11 12 Mean SD
PTA, hearing threshold at 0.5, 1, 2, and 4 kHz of the implanted ear; SDS 65 dB, speech discrimination scores at 65 dB; SRT, speech reception threshold; SD, standard deviation; VSB, Vibrant Soundbridge; HA, hearing aid.
Left Right Left Left Right Right Right Left Left Right Right Left 75 80 90 60 85 85 75 95 65 100 80 75 80.4 11.6 0% 0% 0% 70% 0% 10% 0% 0% 50% 0% 0% 40% 14.2% 24.7% 40 23 33 22 56 43 36 37 26 44 36 52 37.3 10.6 63 56 91 51 74 63 76 83 41 94 61 98 70.9 18.1 23 33 58 29 18 20 40 46 15 50 25 46 33.6 14.1 x x x x x x x x x x x x x x
Air-bone Gap PTA (0.5Y4 kHz) Bone Patient Preference Active Ear Esthetic Reasons HA Problems or Dissatisfaction Bone Conduction threshold 935 dB No. Previous Surgery Gender/age at Surgery (yr)
Reason for Choosing VSB (and not a Conventional HA or Bone-anchored HA)
Individualized Surgical Technique All patients underwent unilateral implantation with the VSB device. The adopted surgical procedure was the RW vibroplasty. In all the subjects, the middle ear was entered via a previous canal wall down mastoidectomy. Two patients underwent a subtotal petrosectomy with fat obliteration (ID 3 and 5) in addition to the VSB placement with closure of the EAC. Another patient underwent this technique for reimplantation (ID 11). The surgical technique for VSB on the RW has been described elsewhere, both for standard mastoidectomy, radical mastoidectomy, and subtotal petrosectomy (3,7). In all patients, some extent of drilling was performed on the RW bone to accommodate the FMT. After placing the FMT, a piece of cartilage was placed to stabilize the top of the FMT. A groove was drilled to place the conductor link in all the cavities and fixed with bone pate and cartilage with the exception of patients undergoing a subtotal petrosectomy. Table 2 shows the surgical findings as well as the specific surgical details of each case.
TABLE 1.
Audiometric Testing The patients were assessed preoperatively and postoperatively at least 1 year after surgery. Preoperative tests included air conduction (AC) and bone conduction (BC) thresholds, and speech discrimination score (SDS) at 65 dB for disyllabic in quiet. Postoperatively, measures included BC thresholds, SDS at 65 dB for disyllabic in quiet with VSB off, and VSB on, and free field (FF)Vwarble tone thresholdVVSB off, and VSB on. If a patient had better hearing in the non-implanted ear, this was occluded or masked during testing to minimize the involvement of the non-tested ear.
Overview of patients’ preoperative audiological data
Inclusion Criteria Patients with a bilateral mixed or conductive hearing loss and a history of cholesteatoma or chronic otitis media, and previous middle ear surgery (range 1Y4 surgeries) were selected. Patients with the VSB placed on the ossicular chain, the oval window, those using FMT couplers, and patients with an intact external auditory canal were excluded. A homogeneous group of 12 patients (six males and six females, ranging in age from 24 to 77 yr) with an open cavity and the FMT placed on the round window niche were enrolled in this study. All patients fulfilled the audiological criteria’s selection for receiving a VSB device (9). For each case, both conventional and bone-anchored hearing aids were also considered as possible hearing solutions. Main patients’ audiological findings and reasons for choosing VSB are shown in Table 1. Local ethics committees approved the investigational plan.
Patient ID
PATIENTS AND METHODS
PTA (0.5Y4 kHz) Air
Preoperative Data
SDS 65 dB
SRT
including long-term audiological results, (b) the need of information about the quality of coupling of the FMT to the RW during surgery and the long-term stability of this coupling, and (c) the importance of the subjective benefit including quality of life (QOL) and quality of sound for the patients wearing the device. The aim of this study is to present our experience with a homogeneous population of patients with open cavities and conductive or mixed hearing loss, who underwent vibroplasty using a careful enrollment strategy, an individualized surgical approach including intraoperative electrocochleography (ECoG), and a long-term follow-up with audiological, QOL, and quality of sound results.
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3 1 1 2 4 1 1 1 1 1 2 1 1.6 1.0
Implant Side
ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES
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Yes 34
Yes 34
No Tympanosclerosis and partially fixed stapes/dry 12
Nothing
No (initially) No ossicular chain/dry 11
Cartilage
Clean and dry cavity, cable extrusion
Reimplantation with petrosectomy May 2014 because of cable extrusion Epithelium around cable, cleaned at office
No No ossicular chain/dry 10
Cartilage
No
Clean and dry cavity, cable extrusion Closed EAC
Reimplantation because of internal receptor extrusion 29/02/2012 Broken cable inside the cavity
Occasional discharge
40
Yes Yes Yes Yes Yes Yes No Yes No No No No 4 5 6 7 8 9
Cartilage Nothing Cartilage Cartilage Cartilage Nothing
Partially fixed stapes/dry Large meningocele, incus interposed and fixed/active Partially fixed stapes sylastic/dry Large perforation/active Mobile stapes, high jugular bulb/dry TORP, high jugular bulb/dry No ossicular chain/dry No ossicular chain/dry 2 3
Perichondrium Fascia
No Yes
Clean and dry cavity, cable extrusion Clean and dry cavity EAC closed No TORP, OW, and RW fibrosis/dry
Fascia
Clean and dry cavity EAC closed Clean and dry cavity Clean and dry cavity Clean and dry cavity Clean and dry cavity
Problem with speech processor that was solved
42 51 24 48 40 12
Yes Yes 76 55
43
Last Follow-up (mo) Comments State of the Cavity at Last Follow-up Closure of EAC Material Between FMT and RW Surgical Findings/dry-active
1
Statistical Analysis The data were collected in a checklist and analyzed by SPSS version 15. Wilcoxon matched-pairs signed-ranks test was used
Surgical findings and follow-up
Subjective Report of Satisfaction Three different questionnaires were administered to all subjects to evaluate subjective benefit. Questionnaires were completed at least 6 months after first fitting. The Nijmegen Cochlear Implant Questionnaire (NCIQ) is a closed-set questionnaire that produces quantifiable scores, initially developed to evaluate how cochlear implantation affects health status (13,14). It distinguishes three general domains: physical, psychological, and social functioning, and comprises specified subdomains: basic sound perception, advanced sound perception, and speech production in the physical domain, and activity and social functioning in the social domain; the psychological functioning domain consists of only one subdomain: selfesteem. Each item was formulated as a statement with a fivepoint response scale to indicate the degree to which the statement was true. Patients were asked to complete it twice, retrospectively (previous to surgery) and prospectively. The Glasgow Benefit Inventory (GBI) is a QOL questionnaire developed to retrospectively assess the outcome of otorhinolaryngology interventions (15). It comprises 18 questions (total score and three subscales) and generates a scale from j100 (maximal detriment) through zero (no change) to +100 (maximal benefit). It assesses the patient’s perception of the overall success of VSB surgery on their social and physical functioning (Overall Benefit, General Health, Social Support, and Physical Health). Both the NCIQ and the GBI have been recently validated in Spanish (16,17). The Hearing Implant Sound Quality Index (HISQUI29) is a questionnaire used to determine an individual´s sound quality in daily life. It measures how good or poor the patient finds the sound quality from their hearing implant system in personal, everyday listening situations. A score less than 60 means very poor sound quality; 60 to 90, poor sound quality; 90 to 120, moderate sound quality; 120 to 150, good sound quality; and 150 to 203, very good sound quality (18).
TABLE 2.
Intraoperative assistance to optimize the fitting of the FMT on the RW membrane was carried out in all the patients. Intraoperative ECoG recordings were performed with the AUDERA (GSI, Eden Prairie, MN). The implant was activated using a model 404 VSB (MED-EL, Innsbruck, Austria) Audio Processor directly connected to the recording system. ECoG was recorded using a custom-made cotton wick electrode (+) placed close to the RW and two subdermal electrodes placed respectively over the ipsilateral tragus (Y) and the sternum (‘‘ground’’). The activation of the cochlea was assessed by the compound action potential (CAP) threshold and amplitude assessed as a function of different RW methods for stabilizing the FMT. The improvement of coupling could be analyzed by verifying how much the intensities of stimulation decreased to obtain the same latency/amplitude. In each case, CAPs were recorded with a small piece of fascia, cartilage, or perichondrium placed over the RW in close contact with the membrane. The decision of placing the FMT directly on the RW membrane or interposing tissue was taken considering best intraoperative response (10Y12). As shown in Table 2, in six cases (50%), the best response was obtained placing a piece of cartilage between the FMT and the RW membrane, in three cases a piece of fascia or perichondrium was interposed, and in the other three cases the FMT was placed directly on the RW membrane. The mean threshold of the CAPs at 2 kHz was 49.4 T 18.6 dB.
User
Electrocochleography: Compound Action Potentials
Yes
L. LASSALETTA ET AL.
Patient ID
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ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES to examine the difference between preoperative and postoperative audiological, QOL, and quality of sound measures. The last follow-up (from 12 to 76 mo) was the study endpoint used in statistical analysis. Data are expressed as mean T standard deviation (SD).
RESULTS Audiological Results The preoperative and postoperative BC thresholds are shown in Figure 1A. There was no significant change in any frequency postoperatively. The VSB mean functional gain (the difference between unaided and aided warble tone thresholds) at 1 year after audio processor activation and again at an average of 42 months postoperatively is depicted in Figures 1B and C. At the last follow-up, functional gain varied from 20.8 T 9.5 to 44.2 T 17.9 dB HL (mean 34.3 T 12.9 dB HL) with the greatest difference occurring at 4 kHz. Significance testing was performed for each individual frequency at 1 year after first fitting and at the last follow-up, and was not found to be statistically significant, except from 0.5 Hz, which showed a mean decrease of 7.1 T 9.6 dB HL (p = 0.026). Word recognition (SDS at 65 dB) significantly improved from 14.2 T 24.7% preoperatively to 82.1 T 21.0% at 1 year postoperatively, and to 82.9 T 21.6% at the last follow-up (p = 0.002). It is worth noting that eight subjects had a score of 0% in the test preoperatively at 65 dB (Table 1). There was no additional significant change in the last follow-up.
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Surgical Complications Clinical signs of infection of the cavity were noticed in one patient (ID 7), which was solved with eardrops. A temporary facial nerve palsy was reported in one patient (ID 6) 10 days after surgery. Treatment with corticosteroids led to normal facial function after 2 months. Eight months after the first fitting, one subject (ID 9) required surgery because of infection and extrusion of the internal coil. The subject initially experienced device benefit but performance declined rapidly after initial VSB fitting. Surgery for repositioning took place before the subject concluded the study participation and postoperative data included here were collected after the second surgery. In four subjects (ID 1, 10, 11, 12), a conductor wire extrusion occurred during the follow-up (Fig. 2). In two patients, extrusion took place in the first 6 months, whereas in the other two it occurred 14 and 16 months postoperatively. One patient (ID 11) was reimplanted and underwent a subtotal petrosectomy with closure of the EAC. Audiological outcomes were similar to those previous to extrusion, and he is again a daily VSB user. Despite the extrusion of the wire, two of these four patients (ID 1, 12) are still actively using their VSB without clinical signs of infection of the conductor wire being observed during regular visits. The remaining subject (ID 10) refused a new surgery and currently she is not taking advantage of the transcutaneous device. No other major medical or surgical complications were reported in this series.
FIG. 1. A, Preoperative and postoperative bone conduction thresholds of the 12 patients. Triangle, preoperative bone conduction thresholds; square, postoperative bone conduction thresholds. B, Mean functional gain values for all patients at 12 months (triangle, dashed line) and at last follow-up (square, continuous line) after implantation. C, Free field aided threshold compared with bone conduction threshold. The vertical bars show standard deviations. BC, bone conduction; FF, free field. Otology & Neurotology, Vol. 36, No. 6, 2015
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FIG. 2. Postoperative pictures of the four patients with extrusion of the wire (arrows). A, patient ID 1, left ear; B, patient ID 11, right ear; C, patient ID 12, left ear; D, patient ID 10, left ear. In this case, the wire was cut resulting from self-manipulation. Arrow shows the site of extrusion.
Subjective Report of Satisfaction A total of 10 patients (83%) completed the NCIQ questionnaire. Upper Figure 3 displays the NCIQ questionnaire results. The evaluation showed a significant improvement for all subdomains. The greatest benefits were observed in the basic sound perception and in the speech production, at which the scores improved from 30.3 to 93.6 and from 48.0 to 93.9, respectively. A total of 10 (83%) patients returned the GBI questionnaire with complete information. All of them had positive overall GBI scores (35.0 T 17.0, range +8 to +61). All reported a positive effect overall (100%) and for the general subcategory (100%), whereas minor improvement was indicated for social support (33%), with no patient reporting a physical wellness (0%). The HISQUI29 questionnaire was filled in by 9 of 12 (75%) subjects. The mean score was 152.8 T 28.0, which means that on average, subjects rated the sound quality as ‘‘very good.’’ Six patients referred to the sound quality as being very good, two as good, only one rated the sound quality as moderate, and none of them scored the quality of sound as bad or very bad. Lower Figure 3 represents mean values of the HISQUI29.
DISCUSSION Main Findings The main findings of this study confirm that RW vibroplasty is an effective treatment for subjects with open
cavities suffering from conductive or mixed hearing losses. Patients have particularly benefited from improved hearing performance and take subjective advantage, which is reflected in QOL and quality of sound questionnaires. Moreover, the lack of significant variation of hearing outcomes at the last follow-up enhances the stability of the coupling. We believe that careful selection, a homogeneous group of patients, individualized surgical technique with intraoperative electrophysiological measures, and careful follow-up of the patients are all crucial factors which lead to stable audiological results. Indications Subjects enrolled in this study had medical or audiological contraindications which prevented the use of traditional hearing aids or refused a percutaneous bone-anchored hearing device. So, the VSB was an attractive treatment option for these subjects suffering from chronic otitis media (COM) with tympanoplasty failures, avoiding the problems of percutaneous pedestals caused by transcutaneous transmission. In recent years, transcutaneous bone conduction implants are playing an important role for patients with open cavities and conductive hearing loss. The Bonebridge system has arisen as a plausible option for some patients with COM and conductive or mixed hearing loss with a BC threshold of up to 45 dB (1). However, it has been recently suggested that according to the output, the real threshold may be closer to 30 dB (19). Moreover, BC implants have the disadvantage of
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ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES
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FIG. 3. Upper, mean NCIQ scores per evaluation moment. A higher value indicates a better result. The error bars represent standard deviations. Lower, mean scores of the HISQUI29 questionnaire, grouped by sound quality (very bad or bad, 0 patients; moderate, 1 patient; good, 2 patients; very good, 6 patients).
stimulating both cochleas at the time, leading to poorer results in terms of localization. Therefore, a patient with an open cavity with mixed hearing loss that may not benefit from surgery or hearing aids in which the bone conduction threshold exceeds those recommended for BC implants may be the main indication for vibroplasty. Our QOL results confirm the patient satisfaction with this system when it is carefully indicated. Hearing Results In our study, there was no significant change in BC after surgery, the mean functional gain was 34.3 dB, and SDS improved from 14 to 85% postoperatively. Our data agree with those described in other VSB studies (20). In a systematic review of the safety and effectiveness of the VSB, Klein et al. (21) reported an average functional gain for the VSB of 27.1 dB, ranging from 12.9 to 47.2 dB across 39 studies that included a total of 796 patients. If we observe Figures 1B and C, we may notice that the gains at 1 year after first fitting are slightly higher than those obtained at the last follow-up, but no significant difference was found except at 0.5 Hz. This slight
decrease has been previously described also after implantation by the transmastoidal posterior tympanotomy approach (22). On the other hand, the aided effective exceeds the BC threshold by approximately 7 dB HL at 2 and 4 kHz. Colletti (23) published a mean gain value of 9.7 dB at the 60-month follow-up, with the highest gains obtained at 1 and 2 kHz, at which a significant overclosure of the VSB-air bone gap was observed. According to Colletti’s group, the ‘‘underclosure’’ for frequencies less than 1 kHz is caused by the frequency roll-off of the FMT below 1 kHz and not to a mismatch in the respective diameters of the FMT and the RW membrane and niche, which would be present systematically at all frequencies. Disyllabic word recognition improved from a mean of 14% preoperatively to 83% postoperatively, with all subjects demonstrating an increase with the VSB. After 1 year of device use, 11 of 12 patients scored 50% or higher. In terms of day-to-day life, this represents the difference between not being able to engage in everyday conversation and being able to do so successfully. The results are consistent with previous findings (2,24). Otology & Neurotology, Vol. 36, No. 6, 2015
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3, successful 42 (12Y76) 4/12 (33%) Present study, 2014
Existing open cavity/subtotal petrosectomy
Not stated Various approaches 9/533 (1.7%) Klein et al., 2013
Comments Revision Surgery
Revision surgery to reposition the FMT Two revision procedures to cover the wire In 4 patients, repeated extrusion after revision surgery Not stated 18 (range 0Y36) 41.2 (range 5Y64) 51 (range 26Y73) Existing open cavity Existing open cavity Transcanal 2/21 (9%) 1/13 (8%) 5/13 (38%) Skarzinsky et al., 2014 De Abajo et al., 2013 Zwartenkot et al., 2011
Mean Follow-up (mo) Approach No. Extrusions Author, yr
Complications In this study, a high incidence of conductor link extrusions was found. This complication has been reported in patients undergoing VSB implantation (25,28) (Table 3). Klein et al. (21) reported 1.7% of patients who experienced device extrusion or migration in a systematic review of the safety of the VSB, which included 22 studies involving 533 patients. However, this rate may be higher, especially when considering implantation in open cavities. Zwartenkot et al. (22) described five cases (38%) of conductor wire extrusions in a series of 13 patients with severe external otitis undergoing a transcanal approach for VSB implantation. The wire extrusion was noticed at a mean postoperative period of 25 months (range, 4Y41 mo). Interestingly, four of these patients were reimplanted, a new extrusion occurring in three of them. Although the approach by open cavity versus transcanal may not be comparable, these findings reflect the high tendency of extrusion of the conductor wire. As in our series, some patients are still users despite having the extruded wire in the EAC. It has been recommended to drill a deep groove for placing the conductor link in open cavities (29). This was carefully performed in all our patients. However, extrusion occurred in four cases, all of them lateral to the facial ridge. This finding may be differentiated from migration of the FMT from the RW niche, which may reflect imperfect coupling or stabilization of the FMT. Nevertheless, because
Overview of VSB extrusions reported in the literature
Coupling The dual mechanism for compensation of the conductive loss (air-bone gap) and the cochlear loss (BC threshold) may act differently across the patients. Many plausible factors explain such variability among which the coupling of FMT to RW membrane may be crucial. If the FMT is not in full, close, and stable contact with the RW membrane, there will be inefficiencies in transferring vibratory energy supplied by the audio processor (3). One controversial topic regarding VSB coupling to the RW is the necessity or not of interposing some tissue between the FMT and the RW membrane. Although some authors have recommended to directly place the FMT on the RW (2,25), interposition of perichondrium or cartilage has been proposed to be safer and to increase the sound transmission (26,27). Our results suggest that the decision must be individualized for each case according to the anatomical findings and especially to the CAP feedback. Although in half of our cases the best intraoperative electrophysiological response was obtained interposing a piece of cartilage between the FMT and the RW membrane, we believe that there is not a single way to assure the best coupling, and that electrophysiology is essential to confirm the adopted technique in each particular case. As some studies have described the loss of natural coupling material (i.e., fascia or cartilage) and the importance of avoiding any bone contact with the FMT (23,25), the use of couplers may be useful in certain cases of vibroplasty. To optimize the contact between the FMT and the round window membrane, the manufacturer has recently launched a new generation of couplers that have yet to be tested (9).
After revision surgery, hearing was restored The performance of the device remained stable Despite the extrusion of the wire in the EAC, the patients are still actively using their VSB Systematic revision of VSB studies reporting adverse events
L. LASSALETTA ET AL.
TABLE 3.
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ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES of the cases of wire extrusion which appeared in our group of patients, we suggest that the subtotal petrosectomy with closure of the EAC may be a safer approach for most patients undergoing RW vibroplasty in open cavities. Although potential complications of this technique must be explained to every candidate, it has become our preferred technique for VSB implantation in open cavities. QOL-HISQUI29 Significant changes in self-reported QOL questionnaires were found in our study. Overall, patient satisfaction with the VSB was very good, suggesting that patients perceived system benefit in their daily life (24,26,27,30,31). Interestingly, our patients rated a mean HISQUI29 score corresponding to ‘‘very good’’ sound quality. We see this finding of particular interest, as the quality of sound has been an argument in favor of middle ear implants as opposed to hearing aids or bone conduction implants. As an example, the mean HISQUI29 score for patients with cochlear implants revealed ‘‘moderate’’ sound quality in the study by Amann and Anderson (18). The quality of sound of middle ear implants has been rated as better than both conventional hearing aids and bone conduction implants, as direct ossicular drive maximizes the ability to hear naturally produced sound with minimal distortion (7,32Y34).
CONCLUSIONS In our experience, the RW vibroplasty represents an effective treatment option for patients with the combination of a conductive or mixed hearing loss and an open cavity, who are not suitable candidates for conventional middle ear surgery or air conduction hearing aids. Patients with mixed hearing loss, who may not benefit from a transcutaneous bone conduction device, seem to be the best candidates. The intraoperative CAP measurement is a useful tool to optimize the FMT placement to achieve maximum energy transfer to the inner ear. To avoid the high rate of extrusion, middle ear obliteration may be taken into consideration in these patients. Acknowledgments: The authors would like to thank Peter Grasso for his support with the intraoperative measures and writing the article.
REFERENCES 1. Lassaletta L, Sanchez-Cuadrado I, Munoz E, et al. Retrosigmoid implantation of an active bone conduction stimulator in a patient with chronic otitis media. Auris Nasus Larynx 2014;41:84Y7. 2. Colletti V, Soli SD, Carner M, et al. Treatment of mixed hearing losses via implantation of a vibratory transducer on the round window. Int J Audiol 2006;45:600Y8. 3. Beltrame AM, Martini A, Prosser S, et al. Coupling the Vibrant Soundbridge to cochlea round window: auditory results in patients with mixed hearing loss. Otol Neurotol 2009;30:194Y201. 4. Cremers CW, Verhaegen VJ, Snik AF. The floating mass transducer of the Vibrant Soundbridge interposed between the stapes and tympanic membrane after incus necrosis. Otol Neurotol 2009;30:76Y8.
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5. Dumon T. Vibrant Soundbridge middle ear implant in otosclerosis: techniqueVindication. Adv Otorhinolaryngol 2007;65:320Y2. 6. Frenzel H, Hanke F, Beltrame M, et al. Application of the Vibrant Soundbridge to unilateral osseous atresia cases. Laryngoscope 2009;119:67Y74. 7. Linder T, Schlegel C, DeMin N, et al. Active middle ear implants in patients undergoing subtotal petrosectomy: new application for the Vibrant Soundbridge device and its implication for lateral cranium base surgery. Otol Neurotol 2009;30:41Y7. 8. Venail F, Lavieille JP, Meller R, et al. New perspectives for middle ear implants: first results in otosclerosis with mixed hearing loss. Laryngoscope 2007;117:552Y5. 9. Vibrant Soundbridge. Candidacy. Available at: http://www.vibrantmedel.com. 10. Colletti V. Intraoperative electrocochleographic (ECoG) evaluation of cochlear mechanical stimulation via the round window with the floating mass transducer of the Med-El Vibrant Soundbridge. VSB Symposium and Workshop (abstr); Hannover, Germany: 2009. 11. Colletti V, Grasso P. Assessment of coupling of the Vibrant Soundbridge FMT for various middle ear placements. 5th International Symposium & Workshop on Objective Measures in Cochlear and Brainstem Implants. Varese, Italy: 9Y12 (abstr). 2007. 12. Colletti V, Mandala M, Colletti L. Electrocochleography in round window Vibrant Soundbridge implantation. Otolaryngol Head Neck Surg 2012;146:633Y40. 13. Hinderink JB, Krabbe PF, Van Den Broek P. Development and application of a health-related quality-of-life instrument for adults with cochlear implants: the Nijmegen cochlear implant questionnaire. Otolaryngol Head Neck Surg 2000;123:756Y65. 14. Krabbe PF, Hinderink JB, van den Broek P. The effect of cochlear implant use in postlingually deaf adults. Int J Technol Assess Health Care 2000;16:864Y73. 15. Robinson K, Gatehouse S, Browning GG. Measuring patient benefit from otorhinolaryngological surgery and therapy. Ann Otol Rhinol Laryngol 1996;105:415Y22. 16. Sanchez-Cuadrado I, Gavilan J, Perez-Mora R, et al. Reliability and validity of the Nijmegen Cochlear Implant Questionnaire in Spanish. Eur Arch Otorhinolaryngol 2015;272:1621Y5. 17. Sanchez-Cuadrado I, Lassaletta L, Perez-Mora R, et al. Reliability and validity of the Spanish Glasgow Benefit Inventory after cochlear implant surgery in adults. Eur Arch Otorhinolaryngol 2015;272:333Y6. 18. Amann E, Anderson I. Development and validation of a questionnaire for hearing implant users to self-assess their auditory abilities in everyday communication situations: the Hearing Implant Sound Quality Index (HISQUI19). Acta Otolaryngol 2014;134: 915Y23. 19. Zwartenkot JW, Snik AF, Mylanus EA, et al. Amplification options for patients with mixed hearing loss. Otol Neurotol 2014;35: 221Y6. 20. Luers JC, Huttenbrink KB, Zahnert T, et al. Vibroplasty for mixed and conductive hearing loss. Otol Neurotol 2013;34:1005Y12. 21. Klein K, Nardelli A, Stafinski T. A systematic review of the safety and effectiveness of the Vibrant Soundbridge. J Otol Rhinol 2013;2:3. 22. Zwartenkot JW, Mulder JJ, Snik AF, Cremers CW. Vibrant Soundbridge surgery in patients with severe external otitis: complications of a transcanal approach. Otol Neurotol 2011;32:398Y402. 23. Colletti L, Mandala M, Colletti V. Long-term outcome of round window Vibrant SoundBridge implantation in extensive ossicular chain defects. Otolaryngol Head Neck Surg 2013;149:134Y41. 24. Baumgartner WD, Boheim K, Hagen R, et al. The Vibrant Soundbridge for conductive and mixed hearing losses: European multicenter study results. Adv Otorhinolaryngol 2010;69:38Y50. 25. Skarzynski H, Olszewski L, Skarzynski PH, et al. Direct round window stimulation with the Med-El Vibrant Soundbridge: 5 years of experience using a technique without interposed fascia. Eur Arch Otorhinolaryngol 2014;271:477Y82. 26. Boheim K, Mlynski R, Lenarz T, et al. Round window vibroplasty: long-term results. Acta Otolaryngol 2012;132:1042Y8. 27. Lim LH, Del Prado J, Xiang L, et al. Vibrant Soundbridge middle ear implantations: experience at National University Hospital Singapore. Eur Arch Otorhinolaryngol 2012;269:2137Y43. Otology & Neurotology, Vol. 36, No. 6, 2015
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28. de Abajo J, Sanhueza I, Giron L, et al. Experience with the active middle ear implant in patients with moderate-to-severe mixed hearing loss: indications and results. Otol Neurotol 2013;34:1373Y9. 29. Beltrame AM, Todt I, Sprinzl G, et al. Consensus statement on round window vibroplasty. Ann Otol Rhinol Laryngol 2014;123:734Y40. 30. Yu JK, Tsang WS, Wong TK, et al. Outcome of Vibrant Soundbridge middle ear implant in Cantonese-speaking mixed hearing loss adults. Clin Exp Otorhinolaryngol 2012;5:S82Y8. 31. Zwartenkot JW, Hashemi J, Cremers CW, et al. Active middle ear implantation for patients with sensorineural hearing loss and external otitis: long-term outcome in patient satisfaction. Otol Neurotol 2013; 34:855Y61.
32. Marino R, Linton N, Eikelboom RH, et al. A comparative study of hearing aids and round window application of the Vibrant Sound Bridge (VSB) for patients with mixed or conductive hearing loss. Int J Audiol 2013;52:209Y18. 33. Kahue CN, Carlson ML, Daugherty JA, et al. Middle ear implants for rehabilitation of sensorineural hearing loss: a systematic review of FDA approved devices. Otol Neurotol 2014;35: 1228Y37. 34. Atas A, Tutar H, Gunduz B, et al. Vibrant SoundBridge application to middle ear windows versus conventional hearing aids: a comparative study based on international outcome inventory for hearing aids. Eur Arch Otorhinolaryngol 2014;271:35Y40.
Otology & Neurotology, Vol. 36, No. 6, 2015
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Pros and Cons of Round Window Vibroplasty in Open Cavities: Audiological, Surgical, and Quality of Life Outcomes Luis Lassaletta, Miryam Calvino, Isabel Sa´nchez-Cuadrado, Rosa M. Pe´rez-Mora, Elena Mun˜oz, and Javier Gavila´n Department of Otolaryngology, ‘‘La Paz’’ University Hospital, IdiPAZ, Madrid, Spain
Objective: To evaluate the audiological, surgical, quality of life, and quality of sound outcomes in adults with open cavities implanted with the Vibrant Soundbridge (VSB) implant using round window (RW) vibroplasty approach. Study Design: Retrospective study. Setting: Otolaryngology department, tertiary referral hospital. Subjects and Methods: Twelve adult patients with conductive or mixed hearing loss, all with previous middle ear surgery, underwent RW vibroplasty in an open cavity. Compound action potential thresholds were assessed during surgery. Surgical complications were recorded. Subjective benefit was evaluated using the Nijmegen Cochlear Implant Questionnaire (NCIQ), Glasgow Benefit Inventory (GBI), and Hearing Implant Sound Quality Index (HISQUI29) tests. Results: Mean follow-up was 42 months (range 12Y76). There was no significant change in bone conduction thresholds after surgery. Mean functional gain was 34.3 dB and speech dis-
crimination score at 65 dB significantly improved from 14 to 83%. Extrusion of the wire link was the main surgical complication in four patients. All NCIQ domains improved after surgery. All patients had a positive overall GBI score (mean 35.0). Mean HISQUI29 score was 152.8, on average the quality of sound being defined as ‘‘very good.’’ Conclusion: VSB is an effective method of hearing restoration for adults with open cavities suffering from conductive or mixed hearing loss. Intraoperative electrocochleography may be considered of significant help to check the coupling to the inner ear. The high rate of extrusion suggests that middle ear obliteration may be considered in these patients. Key Words: ComplicationsV Conductive hearing lossVElectrocochleographyVMixed hearing lossVQuality of lifeVQuality of soundVRound windowV Subjective questionnairesVVibrant SoundbridgeVVibroplastyV Wire extrusion. Otol Neurotol 36:944Y952, 2015.
Restoration of hearing in patients with open cavities is a matter of controversy. Most patients suffer from conductive or mixed hearing loss, and treatment options include reconstructive middle ear surgery, conventional hearing aids, bone conduction implants, and middle ear implants (1). The Vibrant Soundbridge (VSB; MED-EL, Innsbruck, Austria) is an active middle ear implant device aiming to compensate for moderate-to-severe, ski-slope sensorineural (SNHL), mixed and conductive hearing losses. The VSB delivers vibratory energy to a vibratory structure of the middle ear via the floating mass transducer (FMT). For SNHL, the FMT is attached to the long process of the incus, whereas in cases where the ossicular chain is missing, interrupted, or malformed, the FMT can stimulate the cochlea directly via the round window (RW)
membrane or via the stapes superstructure, bypassing the external auditory canal (EAC) and middle ear. The mechanical stimulation of the inner ear may be considered for patients suffering from chronic diseases with previously unsuccessful reconstruction surgeries. Since the first study about direct RW stimulation with the VSB by Colletti (2), several articles have been published on the treatment of patients with chronic ear and mixed or conductive hearing loss (3Y8). Currently, the RW niche technique, termed as RW vibroplasty, is the most frequent application for patients with conductive or mixed hearing loss. The advantage of the FMT on the RW membrane is assumed because the middle ear is bypassed, being the effective point of vibration beyond the site of pathologic findings, and thus, the amplification provided by the VSB should be totally available for inner ear stimulation. Although most studies show remarkable audiological improvement with VSB vibroplasty, some aspects still remain controversial: (a) the lack of a systematic approach to patients with open cavities after RW vibroplasty
Address correspondence and reprint requests to Luis Lassaletta, M.D., Department of Otolaryngology, IdiPAZ, Hospital La Paz, Paseo de la Castellana, 261, 28046 Madrid, Spain; E-mail: [email protected] The authors disclose no conflicts of interest.
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x x x x x x x
x
x x
x
x x
x x
x x x x x x x
x x
F/38 M/61 F/64 M/42 M/47 F/36 M/62 F/34 M/41 F/77 M/24 F/70 49.7 16.6 1 2 3 4 5 6 7 8 9 10 11 12 Mean SD
PTA, hearing threshold at 0.5, 1, 2, and 4 kHz of the implanted ear; SDS 65 dB, speech discrimination scores at 65 dB; SRT, speech reception threshold; SD, standard deviation; VSB, Vibrant Soundbridge; HA, hearing aid.
Left Right Left Left Right Right Right Left Left Right Right Left 75 80 90 60 85 85 75 95 65 100 80 75 80.4 11.6 0% 0% 0% 70% 0% 10% 0% 0% 50% 0% 0% 40% 14.2% 24.7% 40 23 33 22 56 43 36 37 26 44 36 52 37.3 10.6 63 56 91 51 74 63 76 83 41 94 61 98 70.9 18.1 23 33 58 29 18 20 40 46 15 50 25 46 33.6 14.1 x x x x x x x x x x x x x x
Air-bone Gap PTA (0.5Y4 kHz) Bone Patient Preference Active Ear Esthetic Reasons HA Problems or Dissatisfaction Bone Conduction threshold 935 dB No. Previous Surgery Gender/age at Surgery (yr)
Reason for Choosing VSB (and not a Conventional HA or Bone-anchored HA)
Individualized Surgical Technique All patients underwent unilateral implantation with the VSB device. The adopted surgical procedure was the RW vibroplasty. In all the subjects, the middle ear was entered via a previous canal wall down mastoidectomy. Two patients underwent a subtotal petrosectomy with fat obliteration (ID 3 and 5) in addition to the VSB placement with closure of the EAC. Another patient underwent this technique for reimplantation (ID 11). The surgical technique for VSB on the RW has been described elsewhere, both for standard mastoidectomy, radical mastoidectomy, and subtotal petrosectomy (3,7). In all patients, some extent of drilling was performed on the RW bone to accommodate the FMT. After placing the FMT, a piece of cartilage was placed to stabilize the top of the FMT. A groove was drilled to place the conductor link in all the cavities and fixed with bone pate and cartilage with the exception of patients undergoing a subtotal petrosectomy. Table 2 shows the surgical findings as well as the specific surgical details of each case.
TABLE 1.
Audiometric Testing The patients were assessed preoperatively and postoperatively at least 1 year after surgery. Preoperative tests included air conduction (AC) and bone conduction (BC) thresholds, and speech discrimination score (SDS) at 65 dB for disyllabic in quiet. Postoperatively, measures included BC thresholds, SDS at 65 dB for disyllabic in quiet with VSB off, and VSB on, and free field (FF)Vwarble tone thresholdVVSB off, and VSB on. If a patient had better hearing in the non-implanted ear, this was occluded or masked during testing to minimize the involvement of the non-tested ear.
Overview of patients’ preoperative audiological data
Inclusion Criteria Patients with a bilateral mixed or conductive hearing loss and a history of cholesteatoma or chronic otitis media, and previous middle ear surgery (range 1Y4 surgeries) were selected. Patients with the VSB placed on the ossicular chain, the oval window, those using FMT couplers, and patients with an intact external auditory canal were excluded. A homogeneous group of 12 patients (six males and six females, ranging in age from 24 to 77 yr) with an open cavity and the FMT placed on the round window niche were enrolled in this study. All patients fulfilled the audiological criteria’s selection for receiving a VSB device (9). For each case, both conventional and bone-anchored hearing aids were also considered as possible hearing solutions. Main patients’ audiological findings and reasons for choosing VSB are shown in Table 1. Local ethics committees approved the investigational plan.
Patient ID
PATIENTS AND METHODS
PTA (0.5Y4 kHz) Air
Preoperative Data
SDS 65 dB
SRT
including long-term audiological results, (b) the need of information about the quality of coupling of the FMT to the RW during surgery and the long-term stability of this coupling, and (c) the importance of the subjective benefit including quality of life (QOL) and quality of sound for the patients wearing the device. The aim of this study is to present our experience with a homogeneous population of patients with open cavities and conductive or mixed hearing loss, who underwent vibroplasty using a careful enrollment strategy, an individualized surgical approach including intraoperative electrocochleography (ECoG), and a long-term follow-up with audiological, QOL, and quality of sound results.
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3 1 1 2 4 1 1 1 1 1 2 1 1.6 1.0
Implant Side
ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES
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Yes 34
Yes 34
No Tympanosclerosis and partially fixed stapes/dry 12
Nothing
No (initially) No ossicular chain/dry 11
Cartilage
Clean and dry cavity, cable extrusion
Reimplantation with petrosectomy May 2014 because of cable extrusion Epithelium around cable, cleaned at office
No No ossicular chain/dry 10
Cartilage
No
Clean and dry cavity, cable extrusion Closed EAC
Reimplantation because of internal receptor extrusion 29/02/2012 Broken cable inside the cavity
Occasional discharge
40
Yes Yes Yes Yes Yes Yes No Yes No No No No 4 5 6 7 8 9
Cartilage Nothing Cartilage Cartilage Cartilage Nothing
Partially fixed stapes/dry Large meningocele, incus interposed and fixed/active Partially fixed stapes sylastic/dry Large perforation/active Mobile stapes, high jugular bulb/dry TORP, high jugular bulb/dry No ossicular chain/dry No ossicular chain/dry 2 3
Perichondrium Fascia
No Yes
Clean and dry cavity, cable extrusion Clean and dry cavity EAC closed No TORP, OW, and RW fibrosis/dry
Fascia
Clean and dry cavity EAC closed Clean and dry cavity Clean and dry cavity Clean and dry cavity Clean and dry cavity
Problem with speech processor that was solved
42 51 24 48 40 12
Yes Yes 76 55
43
Last Follow-up (mo) Comments State of the Cavity at Last Follow-up Closure of EAC Material Between FMT and RW Surgical Findings/dry-active
1
Statistical Analysis The data were collected in a checklist and analyzed by SPSS version 15. Wilcoxon matched-pairs signed-ranks test was used
Surgical findings and follow-up
Subjective Report of Satisfaction Three different questionnaires were administered to all subjects to evaluate subjective benefit. Questionnaires were completed at least 6 months after first fitting. The Nijmegen Cochlear Implant Questionnaire (NCIQ) is a closed-set questionnaire that produces quantifiable scores, initially developed to evaluate how cochlear implantation affects health status (13,14). It distinguishes three general domains: physical, psychological, and social functioning, and comprises specified subdomains: basic sound perception, advanced sound perception, and speech production in the physical domain, and activity and social functioning in the social domain; the psychological functioning domain consists of only one subdomain: selfesteem. Each item was formulated as a statement with a fivepoint response scale to indicate the degree to which the statement was true. Patients were asked to complete it twice, retrospectively (previous to surgery) and prospectively. The Glasgow Benefit Inventory (GBI) is a QOL questionnaire developed to retrospectively assess the outcome of otorhinolaryngology interventions (15). It comprises 18 questions (total score and three subscales) and generates a scale from j100 (maximal detriment) through zero (no change) to +100 (maximal benefit). It assesses the patient’s perception of the overall success of VSB surgery on their social and physical functioning (Overall Benefit, General Health, Social Support, and Physical Health). Both the NCIQ and the GBI have been recently validated in Spanish (16,17). The Hearing Implant Sound Quality Index (HISQUI29) is a questionnaire used to determine an individual´s sound quality in daily life. It measures how good or poor the patient finds the sound quality from their hearing implant system in personal, everyday listening situations. A score less than 60 means very poor sound quality; 60 to 90, poor sound quality; 90 to 120, moderate sound quality; 120 to 150, good sound quality; and 150 to 203, very good sound quality (18).
TABLE 2.
Intraoperative assistance to optimize the fitting of the FMT on the RW membrane was carried out in all the patients. Intraoperative ECoG recordings were performed with the AUDERA (GSI, Eden Prairie, MN). The implant was activated using a model 404 VSB (MED-EL, Innsbruck, Austria) Audio Processor directly connected to the recording system. ECoG was recorded using a custom-made cotton wick electrode (+) placed close to the RW and two subdermal electrodes placed respectively over the ipsilateral tragus (Y) and the sternum (‘‘ground’’). The activation of the cochlea was assessed by the compound action potential (CAP) threshold and amplitude assessed as a function of different RW methods for stabilizing the FMT. The improvement of coupling could be analyzed by verifying how much the intensities of stimulation decreased to obtain the same latency/amplitude. In each case, CAPs were recorded with a small piece of fascia, cartilage, or perichondrium placed over the RW in close contact with the membrane. The decision of placing the FMT directly on the RW membrane or interposing tissue was taken considering best intraoperative response (10Y12). As shown in Table 2, in six cases (50%), the best response was obtained placing a piece of cartilage between the FMT and the RW membrane, in three cases a piece of fascia or perichondrium was interposed, and in the other three cases the FMT was placed directly on the RW membrane. The mean threshold of the CAPs at 2 kHz was 49.4 T 18.6 dB.
User
Electrocochleography: Compound Action Potentials
Yes
L. LASSALETTA ET AL.
Patient ID
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ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES to examine the difference between preoperative and postoperative audiological, QOL, and quality of sound measures. The last follow-up (from 12 to 76 mo) was the study endpoint used in statistical analysis. Data are expressed as mean T standard deviation (SD).
RESULTS Audiological Results The preoperative and postoperative BC thresholds are shown in Figure 1A. There was no significant change in any frequency postoperatively. The VSB mean functional gain (the difference between unaided and aided warble tone thresholds) at 1 year after audio processor activation and again at an average of 42 months postoperatively is depicted in Figures 1B and C. At the last follow-up, functional gain varied from 20.8 T 9.5 to 44.2 T 17.9 dB HL (mean 34.3 T 12.9 dB HL) with the greatest difference occurring at 4 kHz. Significance testing was performed for each individual frequency at 1 year after first fitting and at the last follow-up, and was not found to be statistically significant, except from 0.5 Hz, which showed a mean decrease of 7.1 T 9.6 dB HL (p = 0.026). Word recognition (SDS at 65 dB) significantly improved from 14.2 T 24.7% preoperatively to 82.1 T 21.0% at 1 year postoperatively, and to 82.9 T 21.6% at the last follow-up (p = 0.002). It is worth noting that eight subjects had a score of 0% in the test preoperatively at 65 dB (Table 1). There was no additional significant change in the last follow-up.
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Surgical Complications Clinical signs of infection of the cavity were noticed in one patient (ID 7), which was solved with eardrops. A temporary facial nerve palsy was reported in one patient (ID 6) 10 days after surgery. Treatment with corticosteroids led to normal facial function after 2 months. Eight months after the first fitting, one subject (ID 9) required surgery because of infection and extrusion of the internal coil. The subject initially experienced device benefit but performance declined rapidly after initial VSB fitting. Surgery for repositioning took place before the subject concluded the study participation and postoperative data included here were collected after the second surgery. In four subjects (ID 1, 10, 11, 12), a conductor wire extrusion occurred during the follow-up (Fig. 2). In two patients, extrusion took place in the first 6 months, whereas in the other two it occurred 14 and 16 months postoperatively. One patient (ID 11) was reimplanted and underwent a subtotal petrosectomy with closure of the EAC. Audiological outcomes were similar to those previous to extrusion, and he is again a daily VSB user. Despite the extrusion of the wire, two of these four patients (ID 1, 12) are still actively using their VSB without clinical signs of infection of the conductor wire being observed during regular visits. The remaining subject (ID 10) refused a new surgery and currently she is not taking advantage of the transcutaneous device. No other major medical or surgical complications were reported in this series.
FIG. 1. A, Preoperative and postoperative bone conduction thresholds of the 12 patients. Triangle, preoperative bone conduction thresholds; square, postoperative bone conduction thresholds. B, Mean functional gain values for all patients at 12 months (triangle, dashed line) and at last follow-up (square, continuous line) after implantation. C, Free field aided threshold compared with bone conduction threshold. The vertical bars show standard deviations. BC, bone conduction; FF, free field. Otology & Neurotology, Vol. 36, No. 6, 2015
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FIG. 2. Postoperative pictures of the four patients with extrusion of the wire (arrows). A, patient ID 1, left ear; B, patient ID 11, right ear; C, patient ID 12, left ear; D, patient ID 10, left ear. In this case, the wire was cut resulting from self-manipulation. Arrow shows the site of extrusion.
Subjective Report of Satisfaction A total of 10 patients (83%) completed the NCIQ questionnaire. Upper Figure 3 displays the NCIQ questionnaire results. The evaluation showed a significant improvement for all subdomains. The greatest benefits were observed in the basic sound perception and in the speech production, at which the scores improved from 30.3 to 93.6 and from 48.0 to 93.9, respectively. A total of 10 (83%) patients returned the GBI questionnaire with complete information. All of them had positive overall GBI scores (35.0 T 17.0, range +8 to +61). All reported a positive effect overall (100%) and for the general subcategory (100%), whereas minor improvement was indicated for social support (33%), with no patient reporting a physical wellness (0%). The HISQUI29 questionnaire was filled in by 9 of 12 (75%) subjects. The mean score was 152.8 T 28.0, which means that on average, subjects rated the sound quality as ‘‘very good.’’ Six patients referred to the sound quality as being very good, two as good, only one rated the sound quality as moderate, and none of them scored the quality of sound as bad or very bad. Lower Figure 3 represents mean values of the HISQUI29.
DISCUSSION Main Findings The main findings of this study confirm that RW vibroplasty is an effective treatment for subjects with open
cavities suffering from conductive or mixed hearing losses. Patients have particularly benefited from improved hearing performance and take subjective advantage, which is reflected in QOL and quality of sound questionnaires. Moreover, the lack of significant variation of hearing outcomes at the last follow-up enhances the stability of the coupling. We believe that careful selection, a homogeneous group of patients, individualized surgical technique with intraoperative electrophysiological measures, and careful follow-up of the patients are all crucial factors which lead to stable audiological results. Indications Subjects enrolled in this study had medical or audiological contraindications which prevented the use of traditional hearing aids or refused a percutaneous bone-anchored hearing device. So, the VSB was an attractive treatment option for these subjects suffering from chronic otitis media (COM) with tympanoplasty failures, avoiding the problems of percutaneous pedestals caused by transcutaneous transmission. In recent years, transcutaneous bone conduction implants are playing an important role for patients with open cavities and conductive hearing loss. The Bonebridge system has arisen as a plausible option for some patients with COM and conductive or mixed hearing loss with a BC threshold of up to 45 dB (1). However, it has been recently suggested that according to the output, the real threshold may be closer to 30 dB (19). Moreover, BC implants have the disadvantage of
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ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES
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FIG. 3. Upper, mean NCIQ scores per evaluation moment. A higher value indicates a better result. The error bars represent standard deviations. Lower, mean scores of the HISQUI29 questionnaire, grouped by sound quality (very bad or bad, 0 patients; moderate, 1 patient; good, 2 patients; very good, 6 patients).
stimulating both cochleas at the time, leading to poorer results in terms of localization. Therefore, a patient with an open cavity with mixed hearing loss that may not benefit from surgery or hearing aids in which the bone conduction threshold exceeds those recommended for BC implants may be the main indication for vibroplasty. Our QOL results confirm the patient satisfaction with this system when it is carefully indicated. Hearing Results In our study, there was no significant change in BC after surgery, the mean functional gain was 34.3 dB, and SDS improved from 14 to 85% postoperatively. Our data agree with those described in other VSB studies (20). In a systematic review of the safety and effectiveness of the VSB, Klein et al. (21) reported an average functional gain for the VSB of 27.1 dB, ranging from 12.9 to 47.2 dB across 39 studies that included a total of 796 patients. If we observe Figures 1B and C, we may notice that the gains at 1 year after first fitting are slightly higher than those obtained at the last follow-up, but no significant difference was found except at 0.5 Hz. This slight
decrease has been previously described also after implantation by the transmastoidal posterior tympanotomy approach (22). On the other hand, the aided effective exceeds the BC threshold by approximately 7 dB HL at 2 and 4 kHz. Colletti (23) published a mean gain value of 9.7 dB at the 60-month follow-up, with the highest gains obtained at 1 and 2 kHz, at which a significant overclosure of the VSB-air bone gap was observed. According to Colletti’s group, the ‘‘underclosure’’ for frequencies less than 1 kHz is caused by the frequency roll-off of the FMT below 1 kHz and not to a mismatch in the respective diameters of the FMT and the RW membrane and niche, which would be present systematically at all frequencies. Disyllabic word recognition improved from a mean of 14% preoperatively to 83% postoperatively, with all subjects demonstrating an increase with the VSB. After 1 year of device use, 11 of 12 patients scored 50% or higher. In terms of day-to-day life, this represents the difference between not being able to engage in everyday conversation and being able to do so successfully. The results are consistent with previous findings (2,24). Otology & Neurotology, Vol. 36, No. 6, 2015
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3, successful 42 (12Y76) 4/12 (33%) Present study, 2014
Existing open cavity/subtotal petrosectomy
Not stated Various approaches 9/533 (1.7%) Klein et al., 2013
Comments Revision Surgery
Revision surgery to reposition the FMT Two revision procedures to cover the wire In 4 patients, repeated extrusion after revision surgery Not stated 18 (range 0Y36) 41.2 (range 5Y64) 51 (range 26Y73) Existing open cavity Existing open cavity Transcanal 2/21 (9%) 1/13 (8%) 5/13 (38%) Skarzinsky et al., 2014 De Abajo et al., 2013 Zwartenkot et al., 2011
Mean Follow-up (mo) Approach No. Extrusions Author, yr
Complications In this study, a high incidence of conductor link extrusions was found. This complication has been reported in patients undergoing VSB implantation (25,28) (Table 3). Klein et al. (21) reported 1.7% of patients who experienced device extrusion or migration in a systematic review of the safety of the VSB, which included 22 studies involving 533 patients. However, this rate may be higher, especially when considering implantation in open cavities. Zwartenkot et al. (22) described five cases (38%) of conductor wire extrusions in a series of 13 patients with severe external otitis undergoing a transcanal approach for VSB implantation. The wire extrusion was noticed at a mean postoperative period of 25 months (range, 4Y41 mo). Interestingly, four of these patients were reimplanted, a new extrusion occurring in three of them. Although the approach by open cavity versus transcanal may not be comparable, these findings reflect the high tendency of extrusion of the conductor wire. As in our series, some patients are still users despite having the extruded wire in the EAC. It has been recommended to drill a deep groove for placing the conductor link in open cavities (29). This was carefully performed in all our patients. However, extrusion occurred in four cases, all of them lateral to the facial ridge. This finding may be differentiated from migration of the FMT from the RW niche, which may reflect imperfect coupling or stabilization of the FMT. Nevertheless, because
Overview of VSB extrusions reported in the literature
Coupling The dual mechanism for compensation of the conductive loss (air-bone gap) and the cochlear loss (BC threshold) may act differently across the patients. Many plausible factors explain such variability among which the coupling of FMT to RW membrane may be crucial. If the FMT is not in full, close, and stable contact with the RW membrane, there will be inefficiencies in transferring vibratory energy supplied by the audio processor (3). One controversial topic regarding VSB coupling to the RW is the necessity or not of interposing some tissue between the FMT and the RW membrane. Although some authors have recommended to directly place the FMT on the RW (2,25), interposition of perichondrium or cartilage has been proposed to be safer and to increase the sound transmission (26,27). Our results suggest that the decision must be individualized for each case according to the anatomical findings and especially to the CAP feedback. Although in half of our cases the best intraoperative electrophysiological response was obtained interposing a piece of cartilage between the FMT and the RW membrane, we believe that there is not a single way to assure the best coupling, and that electrophysiology is essential to confirm the adopted technique in each particular case. As some studies have described the loss of natural coupling material (i.e., fascia or cartilage) and the importance of avoiding any bone contact with the FMT (23,25), the use of couplers may be useful in certain cases of vibroplasty. To optimize the contact between the FMT and the round window membrane, the manufacturer has recently launched a new generation of couplers that have yet to be tested (9).
After revision surgery, hearing was restored The performance of the device remained stable Despite the extrusion of the wire in the EAC, the patients are still actively using their VSB Systematic revision of VSB studies reporting adverse events
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TABLE 3.
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ROUND WINDOW VIBROPLASTY IN OPEN CAVITIES of the cases of wire extrusion which appeared in our group of patients, we suggest that the subtotal petrosectomy with closure of the EAC may be a safer approach for most patients undergoing RW vibroplasty in open cavities. Although potential complications of this technique must be explained to every candidate, it has become our preferred technique for VSB implantation in open cavities. QOL-HISQUI29 Significant changes in self-reported QOL questionnaires were found in our study. Overall, patient satisfaction with the VSB was very good, suggesting that patients perceived system benefit in their daily life (24,26,27,30,31). Interestingly, our patients rated a mean HISQUI29 score corresponding to ‘‘very good’’ sound quality. We see this finding of particular interest, as the quality of sound has been an argument in favor of middle ear implants as opposed to hearing aids or bone conduction implants. As an example, the mean HISQUI29 score for patients with cochlear implants revealed ‘‘moderate’’ sound quality in the study by Amann and Anderson (18). The quality of sound of middle ear implants has been rated as better than both conventional hearing aids and bone conduction implants, as direct ossicular drive maximizes the ability to hear naturally produced sound with minimal distortion (7,32Y34).
CONCLUSIONS In our experience, the RW vibroplasty represents an effective treatment option for patients with the combination of a conductive or mixed hearing loss and an open cavity, who are not suitable candidates for conventional middle ear surgery or air conduction hearing aids. Patients with mixed hearing loss, who may not benefit from a transcutaneous bone conduction device, seem to be the best candidates. The intraoperative CAP measurement is a useful tool to optimize the FMT placement to achieve maximum energy transfer to the inner ear. To avoid the high rate of extrusion, middle ear obliteration may be taken into consideration in these patients. Acknowledgments: The authors would like to thank Peter Grasso for his support with the intraoperative measures and writing the article.
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