Otosclerosis and Stapes Surgery - part 9 pptx

Karger AG, Basel Stapes surgery in experienced hands is a safe procedure and inner ear age with hearing loss or severe vertigo only seldom occurs.. In the extracochlear group, hearing of

Arnold W, Häusler R (eds): Otosclerosis and Stapes Surgery.

Adv Otorhinolaryngol Basel, Karger, 2007, vol 65, pp 300–307

Protecting the Cochlea during Stapes Surgery: Is There a Role for

corticos-Copyright © 2007 S Karger AG, Basel

Stapes surgery in experienced hands is a safe procedure and inner ear age with hearing loss or severe vertigo only seldom occurs However, in theserare instances, it represents a severe complication and should be avoided in any

dam-case The most important issue in prevention of hearing loss after stapes surgery

is a meticulous surgical technique; nevertheless, hearing loss may occur even intechnically correct and uneventful surgical procedures Mechanisms other thandirect mechanical trauma, e.g inflammation or infection, acoustic and meta-bolic stress and disturbance of fluid balance, may be at the origin of postopera-tive hearing loss Additional pharmacological treatment for the protection of theinner ear, e.g with corticosteroids, has found interest and is applied in clinicalpractice in an attempt to prevent or alleviate auditory dysfunction

Corticosteroids have been shown to reduce noise-induced cochlear damageand hearing loss [1–3], increase recovery after noise trauma [4, 5] and are themainstay in the treatment of sudden sensorineural hearing loss [6, 7] However,efficacy in stapedoplasty is still under debate Riechelmann et al [8] found nopositive effect but increased patient discomfort after intravenous administration

of corticosteroids in stapedoplasty; Hendershot [9] stated that short-acting ticosteroids were able to alleviate postoperative serous labyrinthitis, whereaslong-acting corticosteroids increased the incidence of postoperative vertigo andreduced the success rate Spandow et al [10] reported possible ototoxicity afterlocal administration of hydrocortisone

cor-Possible ways of application are systemic and local application, either viadiffusion through the round window or by direct instillation after opening ofinner ear spaces

Niedermeyer et al [11] have measured concentrations of prednisolone inthe human perilymph after systemic application and found that high doses of

250 mg were necessary to obtain a significant increase of concentration Theyalso noted a great interindividual variability of results

Tobita et al [12] were able to measure uptake of prednisolone, with a peak

1 h after application and a prolonged stay in cochlear tissue only at high doses

of 100 mg/kg (corresponding to a human dosage of 7,000 mg for a 70-kgpatient); at 30 mg/kg, corresponding to 1,000 mg human dosage, they could notdetect an increase in steroid concentration in the tissue with their measurementsystem Relatively high doses of corticosteroid seem to be necessary to exertmeasurable effects in the inner ear, but they carry the risk of systemic sideeffects Therefore, direct instillation of drugs into the cochlea offers severaladvantages, allowing delivery of high drug concentrations to the target organwhile minimizing side effects Some attempts at steroid delivery directly intothe cochlea, such as intratympanic therapy [13] and osmotic micropump infu-sion [14, 15], have been reported

To further evaluate the efficacy and exclude any ototoxic effects, wedecided to design an experimental study on the safety of topically appliedsteroid and protective effects on acoustic hearing in guinea pigs after specifictrauma

Animal Preparation and Application of Corticosteroids

This study complied with the guidelines of the Institutional Review Board All efforts were made to minimize both the number of animals used and their suffering.

Eleven pigmented guinea pigs (21 ears), weighing from 400 to 630 g, were used in the study Guinea pigs were anesthetized by intraperitoneal injection of Ketavet (ketamine, Pharmacia & Upjohn GmbH, Erlangen, Germany; dose: 85 mg/kg), xylazine (Rompun, Bayer, Leverkusen, Germany; dose: 8.5 mg/kg), and atropine (Braun, Melsungen, Germany; dose: 0.3 mg/kg) Body temperature was maintained at 37⬚C during the experiments The otic bulla was exposed via a postauricular incision and opened with a hole of 2 ⫻ 2 mm to allow visualization of the round window.

In the extracochlear study arm, a size of 1 ⫻ 1 mm Gelfoam with 5 ␮l Volon A ® talline triamcinolone acetonide solution, 5 ears, verum group) or saline (Ringer’s solution,

(crys-5 ears, control group) was implanted in contact with the round window membrane In the intracochlear study arm, a cochleostomy of about 1 ⫻ 1 mm in the basal turn of the cochlea was drilled and 3 ␮l Volon A (7 ears, verum group), or Ringer’s solution (4 ears, control group) were infused into the scala tympani, using a microsyringe.

Measurements of Compound Action Potentials

A gold hook electrode was anchored to the bony edge of the round window and nected to a percutaneous plug at the vertex to serve as recording electrodes for the acousti- cally evoked compound action potentials (CAPs) of the auditory nerve.

con-Acoustic thresholds were determined in a soundproof chamber using specific gauss pips The acoustic stimuli were delivered to the ear via a tightly sealed tubed earphone The intensity of the gauss pip was changed in 5-dB steps between 20 and

frequency-119 dB SPL Thresholds of CAPs were determined at 25 frequencies, distributed cally between 250 Hz and 64 kHz In addition, input/output (I/O) functions of CAPs in response to click stimuli of increasing intensity were recorded to assess the cochlear function

logarithmi-at threshold and suprlogarithmi-athreshold levels CAP amplitudes were measured from the first tive peak to the subsequent positive peak of the waveform through a programmed algorithm Frequency-specific thresholds and I/O functions were determined after opening of the bulla, prior to the placement of Gelfoam at the round window or before cochleostomy, and repeated soon after the placement of Gelfoam or cochleostomy and regularly on days 1, 3, 7,

nega-14, 21 and 28 after the operation.

Statistical Analyses

Paired t tests were used to analyze pre- and postoperative results within animals Unpaired t tests were used for comparison of group results Differences were considered sta- tistically significant when p ⬍ 0.05 Mean values are given ⫾ SD.

Extracochlear Study Arm

No significant shifts of mean CAP thresholds at different frequencies havebeen observed after the application of the corticosteroid or in the control group.Whereas thresholds remained unchanged, mean maximal amplitudes of I/Ofunction in response to click stimuli at suprathreshold levels increased signifi-cantly (p ⬍ 0.05) at days 14, 21, and 28 after application of the steroid in com-parison with amplitudes prior to the application There were no significantchanges of amplitudes from pre- to postapplication of saline in the controlgroup (fig 1) These results indicate that there are no ototoxic effects, but onthe contrary, steroids increased amplitudes of CAPs

Intracochlear Study Arm

Soon after cochleostomy, thresholds increased up to about 10–20 dB inboth the corticosteroid group as well as in the control group Cochleostomyitself induced a significant hearing loss (p ⬍ 0.05) in comparison with the

pre 1st day 7th day 14th day 21st day 28th day

*

Fig 1 Mean maximum amplitudes of CAPs at different intervals after extracochlear

application of either corticosteroid or saline Note the significant increase of amplitudes in the steroid group at days 14, 21 and 28 Significant changes (p ⬍ 0.05) are marked with an asterisk.

Mean maximal amplitudes of I/O function, both from the steroid and thecontrol group, decreased immediately after cochleostomy, and were down to thelowest level at the 3rd day In the steroid group, recovery could be found on day

14, which continued until day 28 Amplitudes from the control group stayed at

a low level until day 14 and recovered only after the 21st day following tion, about 1 week later than in the steroid group

Control groups

Fig 2 Mean changes of thresholds after cochleostomy in the steroid and the control

group at different time intervals after operation Significant changes (p ⬍ 0.05) are marked with an asterisk.

The safety and efficacy of topic application of steroids to the inner ear isstill controversial and few reports on possible ototoxicity are available Doubtsabout the effects of steroids on inner ear function still exist [16–18]

In this study, we investigated the safety of topically applied steroid andpossible protective effects on acoustic hearing in guinea pigs after surgicaltrauma to the inner ear Our findings from this study were consistent with thosestudies which did not find ototoxic effects

In the extracochlear group, hearing of animals in both the steroid as well asthe control group did not change significantly from the time of application ofthe drug up to 28 days after surgery; on the contrary, even enhanced amplitudes

of CAPs were found in the steroid group The latter phenomena could be tially interpreted by the study of Shirwany et al [19], in which they observedthat blood flow in the cochlea increased after application of the steroid Anotherpossible interpretation could be that the surgical procedure of preparation andopening of the bulla and placing the recording electrode already introduced aminor trauma to the inner ear Application of the steroid might, as in the intra-cochlear group, have some rescuing effect on inner ear structures Results fromthis first set of experiments clearly demonstrated absence of ototoxicity of thesteroid for the substance, concentration and route of application that were used.Applying drugs onto the round window membrane has previously been shown

par-to be a reliable route for the delivery of drugs par-to the inner ear Nomura [20],Bachmann et al [21] and Parnes et al [13] using triamcinolone, dexametha-sone, prednisolone-21-hydrogen succinate and hydrocortisone, respectively,demonstrated that corticosteroids permeate through the round window mem-brane into the perilymph and they reported success in the treatment of patientswith sudden hearing loss [22, 23]

In the case of intracochlear application of steroid to the inner ear after asurgical trauma, hearing of animals decreased soon after cochleostomy in bothgroups While hearing loss was initially similar in both groups, thresholds in thesteroid group started to recover from the 7th day and returned close to thepreapplication level on day 28, whereas recovery of thresholds in the controlgroup did not reach the preapplication level on day 28 Possible reasons of hear-ing loss after cochleostomy may be loss of perilymph, acoustic trauma due todrilling noise, and inflammation due to surgical disturbance In principle, peri-lymph loss should be stopped by sealing the opening of the cochleostomy andshould be compensated spontaneously by cerebrospinal fluid, which reaches thecochlea via the open cochlear aqueduct Influence of drilling noise on hearingcan either be a temporal threshold shift, disappearing within a few hours to a week,

or a permanent damage Corticosteroids may contribute to related intracochlear

In recent years, more studies on apoptosis in the auditory system have beenreported It is agreed that any trauma associated with cochlear implant electrodeinsertion has the potential to form reactive oxygen species and to result in loss

of auditory sensory cells through oxidative stress-induced apoptosis [24] It ishypothesized that steroids may have the ability to block the initiating pathways

of sensory cell apoptosis and inhibit the subsequent degeneration of the eral processes of the auditory neurons, thereby enhancing neural preservationfor patients receiving cochlear implants

periph-In conclusion, results from this study indicated that topical application ofsteroid had no ototoxic effect and was able to rescue some cochlear functions inthe guinea pig after trauma to the inner ear Moreover, it was shown that corti-costeroids can have a protective effect against damage of inner ear structuresand hearing loss in stapes surgery They were not able to prevent hearing lossbut to increase recovery There are indications that local application by directinstillation is more effective than diffusion via the round window and can avoidthe side effect of systemic application However, possible local effects, e.g.delayed healing, will have to be investigated

3 Wang Y, Libermann MC: Restraint stress and protection from acoustic injury in mice Hear Res 2002;165:96–102.

4 Lamm K, Arnold W: The effect of prednisolone and non-steroidal anti-inflammatory agents on the normal and noise-damaged guinea pig inner ear Hear Res 1998;115:149–161.

5 Lamm K, Arnold W: Successful treatment of noise induced cochlear ischemia, hypoxia and ing loss Ann NY Acad Sci 1999;28:233–248.

hear-6 Wilson WR, Byl FM, Laird N: The efficacy of steroids in the treatment of idiopathic sudden ing loss: a double-blind clinical study Arch Otolaryngol 1980;106:772–776.

hear-7 Lamm K, Arnold W: How useful is corticosteroid treatment in cochlear disorders? Otorhinolaryngol Nova 1999;9:203–216.

8 Riechelmann H, Tholen M, Keck T, Rettinger G: Perioperative glucocorticoid treatment does not influence early post-laser stapedotomy hearing thresholds Am J Otol 2000;21:809–812.

9 Hendershot EL: Corticosteroid therapy in stapedectomy: a clinical study Laryngoscope 1974;84:1346–1351.

10 Spandow O, Anniko M, Hellström S: Hydrocortisone applied into the round window niche causes electrophysiological dysfunction of the inner ear ORL J Otorhinolaryngol Relat Spec 1989;51: 94–102.

11 Niedermeyer HP, Zahneisen G, Luppa P, Busch R, Arnold W: Cortisol levels in the human lymph after intravenous administration of prednisolone Audiol Neurotol 2003;8:316–321.

peri-12 Tobita T, Senarita M, Hara A, Kusakari J: Determination of prednisolone in the cochlear tissue Hear Res 2002;165:30–34.

13 Parnes LS, Sun AH, Freeman DJ: Corticosteroid pharmacokinetics in the inner ear fluids: an mal study followed by clinical application Laryngoscope 1999;109:1–17.

ani-14 Lefebvre P, Staecker H: Steroid perfusion of the inner ear for sudden sensorineural hearing loss after failure of conventional therapy: a pilot study Acta Otolaryngol 2002;122:698–702.

15 Kopke RD, Hoffer ME, Weter D, O’Leary MJ, Jackson RL: Targeted topical steroid therapy in den sensorineural hearing loss Otol Neurotol 2001;22:475–479.

sud-16 Nordang L, Linder B, Anniko M: Morphologic changes in round window membrane after topical hydrocortisone and dexamethasone treatment Otol Neurotol 2003;24:339–343.

17 Arriaga MA, Goldman S: Hearing results of intratympanic steroid treatment of endolymphatic hydrops Laryngoscope 1998;108:1682–1685.

18 Karlidag T, Yalcin S, Ozturk A, Ustundag B, et al: The role of free oxygen radicals in noise induced hearing loss: effects of melatonin and methylprednisolone Auris Nasus Larynx 2002;29:147–152.

19 Shirwany NA, Seidman MD, Tang W: Effect of transtympanic injection of steroids on cochlear blood flow, auditory sensitivity, and histology in the guinea pig Am J Otol 1998;19:230–235.

20 Nomura Y: Otological significance of the round window, in Pfaltz CR (ed): Advances in Rhino-Laryngology Basel, Karger, 1984, pp 63–71.

Oto-21 Bachmann G, Su J, Zumegen C, Wittekindt C, Michel O: Permeability of the round window brane for prednisolone-21-hydrogen succinate Prednisolone content of the perilymph after local administration vs systemic injection HNO 2001;49:538–542.

mem-22 Chandrasekhar SS: Intratympanic dexamethasone for sudden sensorineural hearing loss: clinical and laboratory evaluation Otol Neurotol 2001;22:18–23.

23 Hillman TM, Arriaga MA, Chen DA: Intratympanic steroids: do they acutely improve hearing in cases of cochlear hydrops? Laryngoscope 2003;113:1903–1907.

24 Scarpidis U, Madnani D, Shoemaker C, et al: Arrest of apoptosis in auditory neurons: implications for sensorineural preservation in cochlear implantation Otol Neurotol 2003;24:409–417.

PD Dr J Kiefer

Klinik und Poliklinik für HNO-Heilkunde, Klinikum r.d Isar der Technischen Universität München

Ismaninger Strasse 22

DE–81675 Munich (Germany)

Tel 49 89 4140 2389, E-Mail J.Kiefer@lrz.tum.de

Arnold W, Häusler R (eds): Otosclerosis and Stapes Surgery.

Adv Otorhinolaryngol Basel, Karger, 2007, vol 65, pp 308–313

Imaging of Postoperative

Sensorineural Complications of

Stapes Surgery

A Pictorial Essay

Denis Ayachea, Delphine Lejeunea, Marc T Williamsb

a ENT Department, and b Department of Imaging, Fondation Rothschild,

Paris, France

Abstract

Sensorineural hearing loss and/or vertigo are rare but severe complications of stapes surgery for otosclerosis, ranging from 0.2 to 3% Management of such complications depends on the underlying cause: intravestibular protrusion of the prosthesis, perilymph fis- tula, labyrinthitis, and reparative granuloma extending into the vestibule Surgery is manda- tory in cases of intravestibular prosthesis or of persistent perilymph fistula In cases of suppurative labyrinthitis or reparative granuloma extending into the vestibule, prognosis is usually poor, despite aggressive medical therapy or revision surgery CT scan or magnetic resonance imaging can frequently help to determine the cause of the inner ear complication

of stapedectomy Demonstrative cases are presented to illustrate the prominent place of imaging in managing sensorineural complications of stapes surgery.

Copyright © 2007 S Karger AG, Basel

Sensorineural hearing loss (SNHL) is a rare but severe complication ofstapes surgery, frequently associated with vertigo, ranging from 0.2 to 3% inprimary stapedectomy for otosclerosis [1, 2] Management and prognosis ofpostoperative SNHL are closely related to its etiology According to previousreports [1, 3, 4], surgical revision is mandatory in cases of intravestibular pros-thesis or perilymph fistula (PLF) On the other hand, suppurative labyrinthitisand granuloma extending into the vestibule are of poor prognosis despitesurgical revision [1, 3, 4] To improve diagnosis of post-stapedectomy SNHL,imaging plays a more and more important role [5–8]

CT Findings

In case of postoperative SNHL or disabling vertigo, CT is performed inemergency because it can show causes which need to be surgically managedpromptly The imaging technique consists in helical CT with multiplanar recon-structions (MPR), with particular attention to reconstructing images along themain axis of the prosthesis

Too Long Prosthesis

As there is no standard definition, we consider the diagnosis of too longpiston syndrome when postoperative vertigo or SNHL are associated with apenetration of the prosthesis of more than 1 mm into the vestibule This caneasily be depicted with CT (fig 1), leading to revision surgery

Pneumolabyrinth

A pneumolabyrinth is defined as the presence of an air bubble in the labyrinth,and has been considered to be the only pathognomonic imaging sign of PLF [7, 8].Nevertheless, a pneumolabyrinth can be observed on CT within the first post-operative days following stapes surgery, without any pejorative meaning (fig 2)

A pneumolabyrinth can readily suggest PLF if it is not observed in theimmediate postoperative period (fig 3), leading the otologist to prompt revision

Fig 1 Intravestibular protrusion of the tip of the prosthesis on axial CT with MPR.

Ayache/Lejeune/Williams 310

surgery On the other hand, if a pneumolabyrinth is observed in the immediatepostoperative period, the decision on whether or not to perform revision surgerymust take into account the evolution of the clinical presentation and audiologicevaluations with aggressive medical therapy

Noncontributive CT Findings

In case of postoperative sensorineural complications of stapes surgery, CT

is considered as negative when it shows a well-located prosthesis without a

Fig 2 a A pneumolabyrinth on axial CT with MPR performed 3 days after dectomy b Follow-up CT showing resolution of the air bubble 3 days later.

stape-Fig 3 Coronal CT showing a pneumolabyrinth in a patient referred for postoperative

SNHL 1 month after surgery (PLF was found at revision surgery).

pneumolabyrinth or opacity of the middle ear, or when it reveals a nonspecificopacity of the middle ear in the immediate postoperative period.

MRI Findings

When CT findings are not relevant, MRI can be helpful to assess theunderlying causes of the postoperative inner ear complications

Intralabyrinthine Hemorrhage

MR examination may show an intralabyrinthine hemorrhage presenting as

a high signal intensity of labyrinthine cavities on both T1- and T2-weightedimages (fig 4) If vestibular bleeding is the only cause to assess postoperativecomplication, the prognosis is usually good with rest and medical therapy [9]

Intralabyrinthine Reparative Granuloma

Intravestibular extension of a reparative granuloma is a rare but severecomplication of stapes surgery CT examination usually shows a nonspecificsoft tissue mass filling in the oval window fossa Conversely, intralabyrinthinefocal hypointensity on T2-weighted images with associated enhancement onpostcontrast T1-weighted images is highly suggestive of reparative granuloma(fig 5) Reparative granuloma has a poor prognosis despite aggressive medicaltherapy, and even revision surgery [4]

Ayache/Lejeune/Williams 312

Fig 5 In this case of postoperative SNHL, the axial T2 -weighted image shows the obliteration of the labyrinthine fluids corresponding to an extension of the reparative granu- loma into the labyrinth.

Fig 6 a In case of postoperative labyrinthitis, the axial T2-weighted image shows partial

obliteration of the labyrinthine cavities b The axial T1 -weighted image after contrast tion shows an enhancement of the cochlea, vestibule and fundus of the internal auditory canal.

Imaging has a predominant role in managing post-stapedectomy SNHL

CT is the first imaging technique to perform It can depict an excessive tration of the prosthesis into the vestibule or a pneumolabyrinth caused by PLF

pene-In case of negative or noncontributive findings, MRI might be helpful, as it canshow reparative granuloma extending into the vestibule, labyrinthitis or import-ant bleeding into the vestibule

6 Swartz JD, Lansman AK, Berger AS, Wolfson RJ, Bell G, Popky GL, Swartz NG: Stapes sis: evaluation with CT Radiology 1986;158:179–182.

prosthe-7 Rangheard AS, Marsot-Dupuch K, Mark AS, Meyer B, Tubiana JM: Postoperative complications

in otospongiosis: usefulness of MR imaging AJNR Am J Neuroradiol 2001;22:1171–1178.

8 Williams MT, Ayache D: Imaging of the postoperative middle ear Eur Radiol 2004;14:482–495.

9 Ayache D, Sleiman J, Nengsu Tchuente A, Elbaz P: Variantes et incidents per-opératoires observés

au cours de la chirurgie de l’otospongiose Ann Otolaryngol Chir Cervicofac 1999;116:8–14.

Arnold W, Häusler R (eds): Otosclerosis and Stapes Surgery.

Adv Otorhinolaryngol Basel, Karger, 2007, vol 65, pp 314–319

Revision Stapes Surgery

Klaus Jahnke, Daniela Solzbacher, Philipp Dost

Department of Otorhinolaryngology, University Hospital of Essen,

Essen, Germany

Abstract

We present the results of our revision stapes operations from 1989 to 2004 (n ⫽ 217) Long-term follow-up was performed in the first 135 cases Eighteen of these patients were revised because of inner ear symptoms, predominantly within the first year One hundred and sixteen cases underwent revision surgery due to conductive hearing loss, on average after 10.6 years One patient was operated because of dysgeusia In 1999, we first described inner ear damage after implantation of gold prostheses Therefore, we developed a titanium implant that was initially investigated in cell culture and subsequently tested in a clinical trial We report on the most frequent causes that led to revision surgery such as adhesions, prosthetic problems, erosions of the long process of the incus, or refixation of the footplate, and on the different surgical techniques In a first series of patients with a conductive hearing loss, a significant hearing improvement of 69.4% of these cases was obtained However, this result very much depends on the selection of cases There was no case of additional sen- sorineural hearing loss Since 1999, we had mainly used titanium implants for replacement in stapes revision surgery In a second series, a significant hearing improvement of 76.2% was found One patient with a platinum Teflon implant had to be revised because of vertigo and conductive hearing loss which was observed during MRI.

Copyright © 2007 S Karger AG, Basel

Stapes surgery is one of the most standardized and successful procedures

in otology This does not apply to revision surgery, which is performed aftershorter or longer periods of time due to very different causes of failure Theresults of the revision surgery are considerably influenced by the selection ofcases and the specific surgical techniques used

The aim of this study was to describe pre- and intraoperative findings in

217 cases, our general surgical rules and special techniques as well as the operative results of the first 135 cases

post-Patients and Methods

From April 1989 to December 2004, one author (K.J.) performed 217 revision stapes surgeries The mean age of the patients was 48.7 years (range 11–78 years) Long-term follow-up was performed in the first 135 cases, done until December 2000.

Eighteen of these patients were revised because of inner ear symptoms, predominantly within the first year (n ⫽ 11), after an interval of 1–10 years (n ⫽ 6) and after more than

10 years (n ⫽ 1) Six cases mainly complained of progressive sensorineural hearing loss;

in 10 cases, sensorineural hearing loss together with vertigo was observed, and 2 patients exclusively had vertigo.

One hundred and sixteen cases underwent revision surgery due to significant tive hearing loss; the interval between the two operations was less than 1 year in 12 cases, 1–10 years in 60 cases and more than 10 years in 44 cases One patient was operated because

conduc-of dysgeusia In total, 76% conduc-of the patients had previously been operated on elsewhere All patients had otosclerosis except 5 with minor ear malformations and 1 with a stapes fracture after skull base trauma.

Additionally, the short-term results of the last 82 cases will be reported.

Results

Surgical Procedures

In stapes revision surgery, there are some important rules according toDietrich Plester First, all operations should be performed under local anesthe-sia whenever possible so that there is control of vertigo when carefully touchingthe implant inserted during the first procedure During the last few years, twomedialized implants had to be left in place because of vertigo while trying tolateralize them In addition, it is an advantage to examine hearing improvement

at the end of surgery Everything has to be explained to the patient prior tosurgery Furthermore, there must be an informed consent that the surgeon hasthe option to postpone surgery at any stage

During the last few years, the erbium:YAG laser proved to be advantageouswhen scars and bony fragments were noted near the vestibulum

Intraoperative Findings

The causes of inner ear symptoms were inner ear otosclerosis, middle earinflammation, excessively long prostheses, gold incompatibility, adherentswab/particles and a fistula In the 2 patients sent to our department withmiddle ear inflammation within 2 weeks postoperatively, the residual hearingcapacity could be saved and slightly improved by rinsing the middle ear withantibiotics and corticoid solution

In 1999, we first described inner ear damage after implantation of goldstapes prostheses [1] Usually, sensorineural hearing loss developed within the

Jahnke/Solzbacher/Dost 316

first postoperative weeks starting in the high frequencies (n ⫽ 4) Early sion showed significant granulation tissue formation around the implant veri-fied by histology (fig 1a) Topical and systemic corticoid therapy resulted inpartial recovery of the high-tone loss in 3 cases (fig 1b) Dermal tests with suchimplants demonstrated a metal allergy only in 1 of 4 cases Therefore, it is morelikely that the high current conductibility of this metal – in contrast to titanium –plays a significant role in such cases [Helm, J., pers comment]

revi-After our report, we got the information that in some other departmentssingle cases of complete deafness were observed Therefore, we developedstapes prostheses made of titanium in co-operation with an industrial partner In

a first step, the biocompatibility of titanium was confirmed in in vitro studieswith human stapes osteoblasts (fig 2a) [2] It is well known that the potential oftitanium to form a tight connection with bone depends on the surface structure.Consequently, the piston was polished and the loop grasping around the incuswas roughened (fig 2b) The loop was altered so that it could not hinder itselfwhen pinched around the long process During that time, we noticed that Fisch

et al [3] had also used titanium implants for stapes replacement in a fewselected cases

Within a prospective clinical study, the initial 47 implants were analyzed Itwas seen that the titanium stapes prosthesis was at least as good in practical use

0 10 20 30 40 50 60 70 80 90 100 110 120

Pre revision Post revision

Fig 1 Sensorineural hearing loss after implantation of gold stapes prostheses

a Granulation tissue close to the implant b An example of a ‘gold incompatibility’ audiogram,

bone conduction only.

as the conventional implants used until now We have observed no hints of anyside effects or incompatibility since autumn 1999, when this new implant wasintroduced [4].

The clinical trial demonstrated an excellent inner ear compatibility Up tonow, we have not observed any sensorineural hearing loss in more than 300cases Therefore, we think that a possible advantage of titanium implants is anexcellent compatibility when the implant is in contact with the perilymph of thevestibulum as well as with the long process of the incus On the other hand, itcannot be judged if there is an increased risk of an osseous fixation by recurrentotosclerosis of the oval window niche

In many revision cases on the basis of conductive hearing loss (n ⫽ 116),different causes were seen (table 1)

According to the findings, the operation techniques were very different: in

102 cases, the adhesions were cut, e.g between the long process of the incusand the tympanic membrane, or in other cases, scar tissue was carefullyremoved from the oval window niche, sometimes with the erbium:YAG laser In

28 cases, only a new adjustment of the prosthesis was necessary; however, inthe majority of cases, a new implant was inserted (n ⫽ 86), mostly a piston.When the end of the long process of the incus was completely cut, which wasparticularly observed with the platinum band Teflon piston, the angled implant

Fig 2 Titanium stapes prostheses a Excellent biocompatibility was confirmed in in vitro studies with human stapes prostheses b Essen titanium stapes prosthesis.

Jahnke/Solzbacher/Dost 318

was used In cases in which the Schuknecht wire prosthesis had been used in thefirst intervention according to Plester, it proved to be very advantageous to cutthe wire with scissors and leave the end in place (n ⫽ 9) (fig 3) In a next step,the vestibulum had to be opened carefully at the posterior circumference, where

a new piston was inserted

Ninety-eight of the patients could be followed up in the long term Therewas no single case of a significant additional sensorineural hearing loss Thehearing improvement in patients with conductive hearing loss was more than

Table 1 Most frequent causes leading to revision

Erosion of the long process of the incus n ⫽ 42

Refixation of the footplate n ⫽ 28

Dysfunction of the eustachian tube n ⫽ 5

Fig 3 Plester’s technique: Divide the

shaft of the Schuknecht wire prosthesis, leave the end in place, open the vestibulum posteriorly (arrow).