10.14639/0392-100X-suppl.1-43-2023-07
Among the functional failures of stapes surgery is recurrent conductive hearing loss, which can occur after a variable period of hearing improvement, from days/months up to many years after surgery. The most common cause of recurrent conductive hearing loss is prosthesis displacement, while fibrous adhesions or stapedotomy hole/oval window re-obliteration due to otosclerosis, occur less frequently. High resolution computed tomography plays an important role in the identification of the cause of hearing loss recurrence. Parallel to this, intra-operative exploration of the middle ear is crucial to confirm the cause of failure and address its treatment, possibly restoring hearing. While generally worse than after primary surgery, hearing outcomes after revision stapes surgery have improved thanks to advancements in pre-operative assessment, intra-operative view and technical refinements.
text/xml
1827-675X
2609
en
Giulia Molinari
http://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
stapedectomy
Recurrence of conductive hearing loss after stapes surgery: a narrative review
Text.Serial.Journal
https://www.actaitalica.it/
43
Annual congress report
2023-04-21
2023-04-20
2023-04-28
2023-04-28
S56-S60
1
Giulia Molinari
2023/04/21
10.14639/0392-100X-suppl.1-43-2023-07
S56
Department of Otolaryngology - Head and Neck Surgery, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy; Department of Specialistic, Diagnostic and Experimental Medicine, Alma Mater Studiorum University, Bologna, Italy
1827-675X
stapedectomy
S60
Recurrence of conductive hearing loss after stapes surgery: a narrative review
https://www.actaitalica.it/article/download/2609/944
43
ACTA OTORHINOLARYNGOLOGICA ITALICA 2023;43(SUPPL.1):S56-S60; doi: 10.14639/0392-100X-suppl.1-43-2023-07




Otology section


Recurrence of conductive hearing loss
after stapes surgery: a narrative review
Recidiva di ipoacusia trasmissiva dopo chirurgia della staffa: una narrative review
Ignacio Javier Fernandez, Federico Rondini, Livio Presutti, Giulia Molinari
Department of Otolaryngology - Head and Neck Surgery, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy;
Department of Specialistic, Diagnostic and Experimental Medicine, Alma Mater Studiorum University, Bologna, Italy


SUMMARY
Among the functional failures of stapes surgery is recurrent conductive hearing loss,
which can occur after a variable period of hearing improvement, from days/months up to
many years after surgery. The most common cause of recurrent conductive hearing loss
is prosthesis displacement, while fibrous adhesions or stapedotomy hole/oval window
re-obliteration due to otosclerosis, occur less frequently. High resolution computed to-
mography plays an important role in the identification of the cause of hearing loss recur-
rence. Parallel to this, intra-operative exploration of the middle ear is crucial to confirm
the cause of failure and address its treatment, possibly restoring hearing. While generally
worse than after primary surgery, hearing outcomes after revision stapes surgery have
improved thanks to advancements in pre-operative assessment, intra-operative view and
technical refinements.
KEY WORDS: endoscopic ear surgery, otosclerosis, stapes surgery, revision surgery,
stapedotomy, endoscopic stapes surgery, conductive hearing loss, stapedectomy

RIASSUNTO
Tra le cause di fallimento funzionale della chirurgia della staffa si annovera la recidiva
di ipoacusia trasmissiva, che può verificarsi dopo un periodo variabile di miglioramento
                                                                                                 Received: December 10, 2022
dell’udito, da giorni/mesi fino a molti anni dopo l’intervento chirurgico. Le cause più co-
                                                                                                 Accepted: January 17, 2023
muni di ipoacusia trasmissiva ricorrente includono lo spostamento della protesi, mentre
le aderenze fibrose o la ri-obliterazione della platinotomia/finestra ovale dovuta all’oto-
                                                                                                 Correspondence
sclerosi, si verificano meno frequentemente. La TC ad alta risoluzione svolge un ruolo
                                                                                                 Giulia Molinari
importante nell’identificazione della causa della recidiva di ipoacusia trasmissiva. Paral-      Department of Otolaryngology - Head and Neck
lelamente, l’esplorazione intra-operatoria dell’orecchio medio è cruciale per confermare         Surgery, IRCCS Azienda Ospedaliero-Universitaria
la causa del fallimento funzionale e gestire correttamente il suo trattamento, con la finalità   di Bologna, via Massarenti 9, Bologna, Italy
di migliorare l’udito. Nonostante i risultati generalmente peggiori rispetto a quelli della      Tel. + 39 0512144176
chirurgia primaria, i risultati della revisione di stapedotomia sono nel tempo migliorati        E-mail: giulia.molinari8@unibo.it
grazie ai progressi nella valutazione pre-operatoria, nella visione intra-operatoria, ed al
perfezionamento della tecnica chirurgica.
                                                                                                   How to cite this article: Fernandez IJ, Ron-
PAROLE CHIAVE: chirurgia endoscopica dell’orecchio, otosclerosi, chirurgia della                   dini F, Presutti L, et al. Recurrence of con-
staffa, chirurgia di revisione, stapedotomia, chirurgia endoscopica della staffa, ipoacusia        ductive hearing loss after stapes surgery: a
trasmissiva, stapedectomia                                                                         narrative review. Acta Otorhinolaryngol Ital
                                                                                                   2023;43(SUPPL.1):S56-S60.           https://doi.
                                                                                                   org/10.14639/0392-100X-suppl.1-43-2023-07

Introduction                                                                                     © Società Italiana di Otorinolaringoiatria
                                                                                                 e Chirurgia Cervico-Facciale
Functional failure of primary stapes surgery can occur due to persistent con-
ductive hearing loss, recurrent conductive hearing loss after a variable period                                 OPEN ACCESS

of hearing improvement, or surgical complications, as in the case of post-op-                    This is an open access article distributed in accordance with
                                                                                                 the CC-BY-NC-ND (Creative Commons Attribution-Non-
erative vertigo, tinnitus, or sensorineural hearing loss. In the case of recurrent               Commercial-NoDerivatives 4.0 International) license. The
conductive hearing loss (CHL), a good functional outcome can be seen for a                       article can be used by giving appropriate credit and mentio-
                                                                                                 ning the license, but only for non-commercial purposes and
variable duration from days/months up to many years after surgery, before                        only in the original version. For further information: https://
the occurrence of new CHL 1. The most common causes of recurrent CHL af-                         creativecommons.org/licenses/by-nc-nd/4.0/deed.en




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                                                                                                   Conductive hearing loss after stapes surgery




ter stapes surgery is prosthesis displacement, while fibrous
adhesion or stapedotomy hole/oval window re-obliteration,
due to otosclerosis, occur less frequently. These are among
the most frequent indications to revision stapes surgery 2,3.
Revision stapes surgery, due to the presence of major pit-
falls such as scarring tissue or extended erosion of the long
process of the incus, is often burdened by higher failure
rates. Indeed, while primary stapes surgery can be con-
sidered a standardised surgery, with relatively consistent
and satisfactory hearing outcomes in most cases, revision
surgery has less predictable and successful functional out-
comes 4-6.
The audiological results of primary surgery reported in the
literature are very good, allowing to reduce the air-bone         Figure 1. Intraoperative view during endoscopic revision stapes surgery for
gap (ABG) within 20 dB for the frequencies 500-3,000 Hz           recurrent hearing loss, showing fracture of the long process of the incus. The
                                                                  white arrow indicates the fracture line.
(PTA 500-3,000) in 93%-98% of cases and within 10 dB
in 72%-94% of cases 7-9. Conversely, the results reported in
the literature for revision surgery show significantly worse
results, with an ABG within 20 dB for PTA 500-3,000 rang-
ing between 40% and 92%, and an ABG closure (< 10 dB)
between 9% and 80.5% 10-15.
In addition, the incidence of neurosensory damage and iat-
rogenic cophosis (“dead ear”) must be considered with an
incidence that is up to 20% for the former and up to 14%
for the latter, according to different series 13,16,17.
It should be noted that the variability of the data on revision
stapes surgery in the literature is extremely large for series
before 1995, when some techniques and materials were
not yet introduced or widely available. Moreover, the dif-
fusion of high-resolution computed tomography (HRCT)
has led in recent years to perform this radiological imag-        Figure 2. Intraoperative view during endoscopic revision stapes surgery
ing routinely before revision surgery, thus improving the         showing another cause of recurrent hearing loss: obliteration of the previous
preoperative diagnostic accuracy of hearing failure. The          stapedotomy hole and of the adjacent oval window (white arrow).
introduction and diffusion of the CO2 laser, malleostape-
dotomy technique, ionometric bone cement and improve-
ment of the accuracy of pre-operative imaging with HRCT           of the incus 2,3. The prosthetic dislocation can be associ-
have allowed an overall improvement of functional results         ated with a localised erosion or fracture of the long pro-
after 1995, with not only better but also more predictable        cess of the incus (Fig. 1), lateralisation of the footplate, or
results 18,19. In fact, an ABG < 20 dB is reported in 75% to      obliterating otosclerosis with closure of the stapedotomy
86% of cases and < 10 dB only in 45% to 80% of cases.             hole (Fig. 2). All these situations can be combined in vari-
However, a proportion of severe sensorineural damage or           ous ways, as detailed in Table I.
“dead ear”, on average lower than in previous studies and         According to the patient’s history, prosthetic dislocation
less variable among the authors (up to 2%), persists and          determines progressive or sudden onset of CHL. In some
this should be a topic to discuss during patient counselling.     cases, the pattern of hearing loss could help in identifying
                                                                  the cause and type of dislocation: if hearing loss occurred
Diagnosis of recurrent conductive hearing                         after induced pressure change (Valsalva manoeuver, high-
                                                                  altitude travel, air travel) or head trauma, the prosthesis is
loss after stapes surgery                                         generally dislocated at the level of the stapedotomy hole.
The possible causes of recurring CHL after stapedoplasty          On the other hand, in the case of progressive or step-by-step
are mainly related to the dislocation of the prosthesis ei-       hearing deterioration, erosion of the long process of the in-
ther from the stapedotomy hole or from the long process           cus and secondary prosthetic dislocation are more likely 2,3.



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I.J. Fernandez et al.




Table I. Summary of causes of recurrent conductive hearing loss after stapes surgery, with related anatomical sites of interest and associated issues to be con-
sidered during revision surgery.
 Causes of recurring conductive hearing loss                                       Site                                   Associated problems
 Dislocation of the prosthesis                                            From the stapedotomy hole                          Short prosthesis
                                                                                                                                Scar tissue
                                                                                From the incus                   Erosion of the long process of the incus
                                                                                                                Fracture of the long process of the incus
 Fracture of the long process of the incus                                           Incus                            Excessive prosthesis crimping
                                                                                                              Erosion and fracture of the long process after
                                                                                                            prosthesis dislocation from the stapedotomy hole
 Lateralisation of the footplate                                                   Footplate                     Erosion of the long process of the incus
                                                                                                                         Obliterating otosclerosis
 Obliterating otosclerosis with closure of the stapedotomy hole                    Footplate                           Dislocation of the prosthesis
                                                                                                                 Erosion of the long process of the incus



Lesinski et al. proposed several mechanisms for prosthet-                         (Figs. 3, 4), while it did not permit to pre-operatively un-
ic migration. First, in cases with the use of a sealing mem-                      derstand the cause of hearing failure in 14 cases show-
brane, some collagen contracture of the membrane itself                           ing a normal position of the prosthesis. No cases of round
lifted the prosthesis above the stapedectomy or stape-                            window obliteration were observed 4.
dotomy fenestration, with greater lateralisation occurring
in thicker sealing materials, in decreasing order fascia,
fat, perichondrium, and vein. Second, adhesive tissue is
frequently found between the prosthesis and the promon-
tory, facial ridge, or pyramidal eminence. In general, the
prosthesis was displaced toward that structure by the pull-
ing forces of collagen contracture of the neomembrane.
No clear mechanism of prosthesis displacement has been
identified in cases of failure after stapedotomy without
graft interposition. However, if no adhesions were found,
the prosthesis was not perpendicular to the plane of the
footplate but displaced in the angulated direction from the
forces evoked by the vibrating incus. In other occasions,
the prosthesis had migrated away from the oval window
because of faulty crimping; i.e., the loop around the incus
neck was found flattened, and the prosthesis migrated off                         Figure 3. Temporal bone high resolution computed tomography, axial
                                                                                  view. On the left, the end of the prosthesis appears dislocated from the
the incus. In 5% (13/260) of patients, the prosthesis was                         oval window.
found attached to the incus neck, but too short to reach the
neomembrane. Less than 1% of these patients were found
to have a prosthesis that was loosely attached to an intact
incus with no other abnormalities 3.
HRCT is the gold standard exam that allows identification
of the cause of recurrent CHL with considerable accuracy.
While HRCT can detect prosthetic dislocation from the
stapedotomy hole, less accurate is the diagnosis of an ero-
sion or fracture of the long process of the incus, unless
the distal fragment is displaced itself 4,12. In a recently
published study by Fernandez et al, of the 18 consecu-                            Figure 4. Temporal bone high resolution computed tomography, coronal
                                                                                  view. On the left the oval window is empty and the prosthesis is displaced
tive cases of recurrent CHL after primary stapes surgery                          upwards towards the Fallopian canal. It is not possible to assess if the incus
who had a pre-operative HRCT scan, pre-operative imag-                            long process is eroded from this imaging. Only exploratory tympanotomy
ing was diagnostic for prosthesis dislocation in 3 cases                          could clarify the cause of prosthesis displacement.



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                                                                                                             Conductive hearing loss after stapes surgery




Intra-operative findings during revision                                           in brackets indicates the number of patients found to have
stapes surgery for recurrent hearing loss:                                         that specific endoscopic situation): partial erosion (10) or
                                                                                   extensive erosion (1) of the incus, fracture of the incus (1),
the role of the endoscope                                                          and incus luxation (1); fixed malleus (1); incorrect anterior
In cases where pre-operative assessment of the cause of re-                        stapedotomy hole (1), re-closed stapedotomy hole (14),
current CHL is not possible, an exploratory tympanotomy                            absent stapedotomy hole (2), fibrous tissue at the level of
allows for proper identification of the cause of stapes sur-                       the stapes (6) – as shown in Figure 5; short prosthesis (7),
gery failure, thanks to the close view on the ossicular chain,                     long/intravestibular prosthesis (1), absent prosthesis (2),
oval window, and prosthesis 13,17.                                                 attached to the incus-out of stapedotomy hole (12), de-
The use of the endoscope in stapes surgery has shown ex-                           tached from incus-inside stapedotomy hole (1), detached
cellent results that are comparable to those with the micro-                       from incus-out of stapedotomy hole (13). Such a detailed
scopic technique, according to several reports 20,23.                              description of intratympanic findings could have been more
Regarding revision stapes surgery, accumulating evidence                           difficult under straight microscopic view.
has led to consider not only that totally endoscopic revision                      Parallel to this, it has been shown that all intra-operative
stapes surgery is safe and effective in experienced hands,                         situations encountered during revision stapes surgery are
but also that the endoscopic approach allows an extremely                          manageable through an exclusive endoscopic approach,
detailed exploration of the entire middle ear cavity through                       supporting the concomitant therapeutic role of this ap-
a transcanal approach, without the need for an endaural or                         proach 4.
retroauricular approach and with the possibility to diagnose
and manage all possible intra-operative scenarios during                           Outcomes after revision stapes surgery
revision surgery. This represents a greater advantage of the                       in patients with recurrent conductive
endoscopic technique compared to the classic microscopic                           hearing loss
approach.
In the experience of the senior authors, in a study involv-                        Primary stapes surgery can be considered successful if an
ing 34 patients, a cause of persistent or recurrent hearing                        ABG of < 10 dB is achieved 22,23. Similarly, the success of
loss was detected in all patients during endoscopic tym-                           revision surgery is generally confirmed by closure of the
panotomy. Of those, 2 presented with persistent CHL and                            post-operative ABG within 10 dB. According to the litera-
32 with recurrent CHL. The intra-endoscopic findings                               ture, revision stapes surgery creates an opportunity for im-
were numerous and occasionally combined (the number                                proving hearing in 24%-80% of cases 10-15.
                                                                                   When deciding on reoperation after primary stapedotomy,
                                                                                   it should also be noted that it is usually a more difficult
                                                                                   procedure than the initial operation, as a consequence of
                                                                                   the need to dissect adhesions in the tympanic cavity, as well
                                                                                   as to manage the previously used prosthesis in atraumatic
                                                                                   way 3-6. Furthermore, it is associated with a higher risk of
                                                                                   complications than in the initial procedure, including hear-
                                                                                   ing loss and injury to the facial nerve.
                                                                                   A recent experience on the use of the endoscopic technique
                                                                                   during revision stapes surgery has shown positive results,
                                                                                   with 89.5% of cases with post-revision ABG within 20 dB
                                                                                   and 68.5% of cases with post-revision ABG within 5 dB.
                                                                                   These data appear to be higher than those reported in the re-
                                                                                   cent literature on stapes revision surgery with microscopic
                                                                                   technique, but larger series with longer follow-up are need-
                                                                                   ed for a proper comparison between the two techniques 8.


Figure 5. Endoscopic transcanal view of revision stapes surgery. The pres-         Conclusions
ence of fibrous and adhesive tissue around the prosthesis and the long pro-
                                                                                   Although primary stapes surgery provides excellent func-
cess of the incus is another cause of recurrent hearing loss after stapes sur-
gery. In these cases, treatment consists of removing this tissue and controlling   tional results in a very large percentage of cases, some pa-
the mobility of the ossicular chain and prosthesis.                                tients may suffer from CHL after a variable period of time.



                                                                                                                                                   S59
I.J. Fernandez et al.




An appropriate intra-operative diagnosis of recurrent CHL                     6
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Conflict of interest statement                                                11
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The authors declare no conflict of interest.                                       revision stapedectomy. Otol Neurotol 2003;24:560-566. https://doi.
                                                                                   org/10.1097/00129492-200307000-00005
Funding                                                                       12
                                                                                   Bernardeschi D, Canu G, De Seta D, et al. Revision stapes surgery:
                                                                                   A review of 102 cases. Clin Otolaryngol 2018;43:1587-1590. https://
This research did not receive any specific grant from fund-                        doi.org/10.1111/coa.13181
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Author contributions                                                          14
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