10.14639/0392-100X-N0612
Objective. Otosclerosis is an osteodystrophic disease of the otic capsule, determining conductive or mixed hearing loss, which can be successfully treated with stapedotomy. The aim of the present multicentric retrospective study was to identify prognostic factors related to better auditory outcomes in stapes surgery.Methods. 581 patients affected by otosclerosis were submitted to stapedotomy under local anaesthesia in two different hospitals. Both Teflon and titanium prostheses were adopted. Results. A statistically significant decrease of postoperative air-conduction thresholds and air–bone gap (ABG) values was seen, whereas the mean bone-conduction threshold did not differ from the preoperative condition. Among the various parameters investigated, the prosthetic material, duration of surgery and intraoperative detection of unexpected anatomical anomalies of the middle ear were found to be related to lower postoperative ABG values. Conclusions. All the previously mentioned parameters played a significant role in determining the postoperative auditory outcomes and can therefore be considered prognostic factors for the success of the stapedotomy.
text/xml
1827-675X
612
en
Andrea Canale
http://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
air-bone gap
Prognostic factors influencing postoperative air-bone gap in stapes surgery
Text.Serial.Journal
https://www.actaitalica.it/
42
Otology
2022-09-30
2020-01-17
2022-10-12
2022-10-12
380-387
1
Andrea Canale
2022/09/30
10.14639/0392-100X-N0612
380
Department of Surgical Sciences, University of Turin, Turin, Italy
1827-675X
air-bone gap
387
Prognostic factors influencing postoperative air-bone gap in stapes surgery
https://www.actaitalica.it/article/download/612/855
42
ACTA OTORHINOLARYNGOLOGICA ITALICA 2022;42:380-387; doi: 10.14639/0392-100X-N0612




Otology


Prognostic factors influencing postoperative air-bone
gap in stapes surgery
Fattori prognostici del miglioramento del gap tra via aerea e via ossea nella chirurgia
della staffa
Andrea Albera1, Fiorella Parandero2, Roberto Andriani2, Roberto Albera1, Giuseppe Riva1, Andrea Canale1
1
 Department of Surgical Sciences, University of Turin, Turin, Italy; 2 Section of Ear Nose and Throat, Fatebenefratelli Hospital,
University of Milan, Milan, Italy


SUMMARY
Objective. Otosclerosis is an osteodystrophic disease of the otic capsule, determining
conductive or mixed hearing loss, which can be successfully treated with stapedotomy. The
aim of the present multicentric retrospective study was to identify prognostic factors related
to better auditory outcomes in stapes surgery.
Methods. 581 patients affected by otosclerosis were submitted to stapedotomy under local
anaesthesia in two different hospitals. Both Teflon and titanium prostheses were adopted.
Results. A statistically significant decrease of postoperative air-conduction thresholds and
air–bone gap (ABG) values was seen, whereas the mean bone-conduction threshold did
not differ from the preoperative condition. Among the various parameters investigated, the
prosthetic material, duration of surgery and intraoperative detection of unexpected anatomi-
cal anomalies of the middle ear were found to be related to lower postoperative ABG values.
Conclusions. All the previously mentioned parameters played a significant role in
determining the postoperative auditory outcomes and can therefore be considered prognostic
factors for the success of the stapedotomy.
KEY WORDS: stapedotomy, conductive hearing loss, prognostic factors, otosclerosis, air-
bone gap

RIASSUNTO                                                                                               Received: January 26, 2022
Obiettivo. L’otosclerosi è un processo osteodistrofico che interessa la capsula otica e determina       Accepted: April 19, 2022
un’ipoacusia trasmissiva o mista che può essere trattata chirurgicamente mediante un intervento
di stapedotomia. Lo scopo del presente studio retrospettivo multicentrico è l’identificazione di        Correspondence
eventuali fattori prognostici correlati a migliori risultati uditivi nella chirurgia della staffa.      Andrea Albera
Metodi. 581 pazienti affetti da otosclerosi sono stati sottoposti a stapedotomia in anestesia           Department of Surgical Sciences, University of
                                                                                                        Turin, Via Genova 3, 10124, Turin, Italy
locale in due diversi ospedali. Sono state adottate protesi sia in teflon sia in titanio.
                                                                                                        Tel. +39 011 6709582
Risultati. I nostri dati hanno dimostrato, nel postoperatorio, una diminuzione statisticamente          E-mail: aalbera@hotmail.com
significativa dei valori di soglia per via aerea e del gap tra via aerea e via ossea (ABG), mentre
i valori medi della soglia per via ossea risultano sovrapponibili alla condizione preoperatoria.
Tra i vari parametri studiati, il materiale della protesi, la durata dell’intervento chirurgico e         How to cite this article: Albera A, Parandero F,
il rilevamento intraoperatorio di anomalie anatomiche dell’orecchio medio sono risultati                  Andriani R, et al. Prognostic factors influencing
correlati a inferiori valori di ABG postoperatorio.                                                       postoperative air-bone gap in stapes surgery. Ac-
                                                                                                          ta Otorhinolaryngol Ital 2022;42:380-387. https://
Conclusioni. Tutti i parametri precedentemente citati svolgono dunque un ruolo significativo
                                                                                                          doi.org/10.14639/0392-100X-N0612
nel modificare gli esiti uditivi postoperatori e possono quindi essere considerati fattori predittivi
per il successo della stapedotomia.
                                                                                                        © Società Italiana di Otorinolaringoiatria
PAROLE CHIAVE: stapedotomia, ipoacusia trasmissiva, fattori prognostici, otosclerosi,                   e Chirurgia Cervico-Facciale
air-bone gap
                                                                                                                       OPEN ACCESS

                                                                                                        This is an open access article distributed in accordance with
Introduction                                                                                            the CC-BY-NC-ND (Creative Commons Attribution-Non-
                                                                                                        Commercial-NoDerivatives 4.0 International) license. The
Otosclerosis is a localised disorder of bone metabolism within the human otic                           article can be used by giving appropriate credit and mentio-
                                                                                                        ning the license, but only for non-commercial purposes and
capsule leading to fixation of the stapes footplate by spongiotic foci located                          only in the original version. For further information: https://
anteriorly to the oval window, thus the region of the fissula ante fenestram 1,2.                       creativecommons.org/licenses/by-nc-nd/4.0/deed.en




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                                                                   Prognostic factors influencing postoperative air-bone gap in stapes surgery




This osteodystrophic phenomenon is one of the most com-          dotomy under local anaesthesia in two different centres,
mon causes of progressive conductive and mixed hearing           AOU Città della Salute e della Scienza of Turin (481 cases,
loss in young adults, particularly between the third and         82.8%) and Fatebenefratelli Hospital of Milan (100 cases,
fifth decades; however, otosclerosis can also frequently be      17.2%).
associated with sensorineural deafness due to progressive        Diagnosis of otosclerosis was based on normal otoscopic
involvement of the endosteal portion of the cochlea 3.           findings, progressive conductive hearing loss worse at
Stapes surgery, a minimally invasive procedure usually           lower tones with air conduction (AC) pure-tone average
performed under local anaesthesia, is considered the             (PTA) ≥ 30 dB in the range 0.5 to 4 kHz, a minimum 15-
gold standard procedure to restore the mechanical sound          dB preoperative ABG level and normal tympanogram (type
transmission through the middle ear 4; nevertheless, a           A) with absence of cochleostapedial reflexes 5.
hearing aid can always be considered a valid alternative for     Exclusion criteria of the present study were patients under-
patients who are not eligible for surgery 5.                     going revision surgery, fluctuating hearing loss with verti-
Several surgical techniques have been described in the           go, tympanic membrane perforation, intraoperative finding
literature, among which the most frequently applied are a        of congenital ossicular chain malformation, epitympanic
conventional procedure, in which the stapes suprastructure       fixation or erosion of the incus and superior or posterior
(SSS) is removed before placement of a prosthesis 4, and         semicircular canal dehiscence.
reverse stapedotomy, originally proposed by Fisch and            A preoperative imaging evaluation was not performed on
in which, for safety, an early perforation of the footplate      any patient in the diagnosis or surgical planning for oto-
followed by insertion of the piston is performed before          sclerosis.
removal of the SSS 6. Although many authors agree on             Each patient was routinely subjected to pure tone audiom-
the lesser intraoperative risk of complications, i.e. floating   etry, by testing all common frequencies up to 8 kHz, before
footplate, with the reversal of steps, their results are very    surgery and at each postoperative control, scheduled at one
discordant with respect to postoperative hearing outcomes        month, six months and one year after surgery. However,
and the same consideration can be asserted regarding             all postoperative hearing thresholds mentioned herein re-
both the material and diameter of the prosthesis 7,8. On the     fer only to PTA values and average ABG (mean hearing
contrary, despite the justifiable preferences of the surgeon,    threshold at 0.5-1-2-4 kHz) assessed at one year after sta-
knowledge of all surgical techniques and experience              pedotomy as to include sufficiently consolidated auditory
with different instruments and prostheses is universally         results.
considered essential in the training background of an            All surgical procedures were performed under local anaes-
otolaryngologist, in order to be able to improvise in the        thesia by the same senior surgeons in the two hospitals.
case of unforeseen circumstances.                                The detailed description of the surgery, which was always
Stapedotomy provides excellent results in terms of air-bone      performed in the same way for all patients, is provided
gap (ABG) closure in the vast majority of cases; however,        in a specific section as supplementary material. The only
in the literature, about 10% of patients do not achieve fully    variables that have been applied to the surgical procedure,
satisfactory hearing restoration following surgery, with         depending on the surgeon’s preference, were the stapes
persistent mild to moderate conductive hearing loss 9,10.        approach and type of prostheses. In some patients, the
A highly successful functional outcome of stapes surgery         conventional steps of stapedotomy (posterior crurotomy,
is commonly referred to postoperative ABG values lower           fracture of the anterior crus and subsequent removal of the
than 10 dB, while the achievement of an ABG closure be-          SSS) were performed before placement of the prosthesis.
tween 10 and 20 dB, despite still being well accepted by         In contrast, reverse stapedotomy was carried out in all other
patients, is considered as a partial success of surgery 11,12.   patients. As for the prosthesis, depending on their habits,
The aim of the present multicentric retrospective study was      the surgeons used either a fluoroplastic (Teflon) piston with
to define whether there are factors that can influence, and      a 0.3- or 0.4- mm shaft diameter, or a titanium soft clip pis-
therefore predict, one-year postoperative auditory improve-      ton with a 0.4 mm shaft diameter. All prostheses considered
ment (in terms of ABG) after stapedotomy performed un-           in the study had a length of 4.5 mm.
der local anaesthesia.                                           Overnight hospitalisation depended on the intraoperative
                                                                 or early postoperative onset of vertigo, nausea and vomit-
                                                                 ing, or transient facial nerve palsy due to local anaesthesia,
Materials and methods                                            which all recovered before discharge; other variables that
The present retrospective study was conducted on 581 pa-         controidicated same-day discharge and affecting the need
tients suffering from otosclerosis and submitted to stape-       for hospitalisation were the absence of a family member or



                                                                                                                                        381
A. Albera et al.




caregiver to arrange comfortable home transport and great        ference between patients submitted to stapedotomy in Tu-
distance between the patient’s home and hospital. Further-       rin and Milan with regards to preoperative and postopera-
more, same-day discharge after stapedotomy was imple-            tive AC PTA, BC PTA and ABG values (p > 0.05).
mented in Turin only for a few years whereas, previously,        Mean preoperative and 1-year postoperative AC PTA, BC
the internal clinical protocol required at least an overnight    PTA and ABG values are reported in Table I. In accord-
hospital stay in any case after surgery.                         ance with the expectations of the intervention, our data
Among the parameters taken into account to define which          demonstrated a statistically significant decrease of mean
factors can affect ABG closure, we considered both gen-          AC PTA thresholds (p < 0.001) and stable BC PTA thresh-
der and age of patients, unilateral or bilateral disease, type   olds (p > 0.05) after stapedotomy at paired-samples t-test.
of hospitalisation (same-day surgery or day hospital with        Furthermore, we highlighted a significant postoperative de-
overnight stay), duration of surgery, diameter of the ex-        crease of ABG values (p < 0.001), with a mean value of
ternal auditory canal (EAC), preoperative ABG, surgical          10.8 dB.
approach to the stapes and characteristics of the prosthe-       At the end of the surgery, 29.3% of patients were monitored
sis. Finally, both the intraoperative detection of anatomi-      for only a few hours before discharge, whereas 70.7% of
cal middle ear abnormalities (narrow oval window niche,          patients were hospitalised for the night and were discharged
very thick posterior crus, obliterative footplate, bulging       the following morning; no patient needed prolonged hospi-
intratympanic facial nerve) and the onset of intraopera-         talisation for more than a day.
tive surgical complications (extreme footplate mobilisation      With regards to the diameter of the EAC highlighted intraop-
or its fracture, transient vertigo, excessive bleeding) were     eratively, 35.7% and 30.5% of the surgeries were performed
also included among the variables taken into account for         with a 6.5 mm and 6 mm diameter speculum, respectively.
the study. The diameter of the EAC was indirectly reported       The other diameters observed were 7 mm (15.5%), 5.5 mm
according to the diameter of the otologic speculum used          (12.8%), 5 mm (3.2%) and 7.5 mm (2.3%).
to perform the surgical procedure and the duration of the        The independent-samples T-test performed among the 581
surgery was recorded in minutes from the first incision of       patients included in the study showed no significant post-
the posterior tympanomeatal flap to the Merocel packing          operative ABG differences between males and females,
of the EAC.                                                      right and left ear, unilateral and bilateral otosclerosis,
                                                                 same-day discharge and overnight hospitalisation (Tab. II).
Statistical analysis                                             With regards to the surgical technique, conventional stape-
Statistical analysis was performed using SPSS 24.0 statisti-     dotomy was correctly performed in 54.8% of patients and
cal software for Microsoft Windows (SPSS, Inc., Chicago,         the reversal of steps was preferred in the remaining 45.2%
IL). Descriptive statistics for both continuous variables        of patients. Although slightly better auditory outcomes
(means and standard deviations) and categorical variables        were highlighted when the platinotomy was performed as
(frequencies) were assessed. Variables were compared by          the first step in the reverse stapedotomy procedure, there
means of parametric tests due to their normally distribu-        was finally no significant difference between the two ap-
tion, in particular the independent-samples and paired-          proaches in terms of ABG closure (p = 0.140, Tab. III).
samples t-test. Pearson correlation was used to explore the      Concerning the stapedial prosthesis tightened to the long
relationship between continuous variables. Two-sided ex-         process of the incus, the surgeons preferred to apply a
                                                                 4- mm diameter piston (n = 439, 75.6%); moreover, a pros-
act tests were used and p values < 0.05 were considered
                                                                 thesis in fluoroplastic material was used in most surgeries
significant for all tests.
                                                                 (n = 480, 82.6%).
                                                                 While we obtained significantly lower postoperative ABG
Results
Among the 581 patients submitted to stapedotomy whose
                                                                 Table I. Preoperative and one-year postoperative auditory results of 581 pa-
characteristics met the study inclusion criteria, 372 patients   tients submitted to stapedotomy. The reported PTA values are average thresh-
were female (64%) and 209 patients were male (36%) with          olds at 0.5, 1, 2 and 4 kHz.
a mean age of 49.3 ± 11 years (range 18-79). Otosclerosis                          Preoperative            Postoperative          P-value
was unilateral in 160 patients (27.5%) and bilateral in 421       AC PTA         56.7 ± 14 (30-86)             38.7 ± 17 (6-120)          < 0.001*
patients (72.5%). Stapedotomy was performed in 303 cases          BC PTA         27.6 ± 11 (9-70)              27.9 ± 14 (2-120)           > 0.05
on the right side (52.2%) and in 278 cases on the left side       ABG            29.2 ± 9 (15-58)               10.8 ± 10 (0-53)          < 0.001*
(47.8%).                                                         All reported values are expressed in dB HL. Ranges are in brackets. AC: air conduction;
An independent-samples T-test reported no significant dif-       BC: bone conduction; ABG: air-bone gap; * statistically significant.




382
                                                                                              Prognostic factors influencing postoperative air-bone gap in stapes surgery




Table II. Average postoperative ABG values according to gender, side of the                anatomical anomalies or to the onset of complications only
disease, unilateral or bilateral nature of the disease and type of hospitalisation         in the 480 patients who underwent stapedotomy in Turin
after stapedotomy.
                                                                                           (Tab. IV).
                                                 Post-Op ABG         P-value
                                                                                           Based on our data, the detection of unexpected anatomical
    Gender                         Male               11.6 ± 9.8 dB        0.166
                                                                                           anomalies during surgery was found in 22.3% of patients
                                  Female             10.4 ± 10.2 dB                        and was reported to significantly affect postoperative hear-
    Side                           Right             10.8 ± 10.2 dB        0.879           ing with higher ABG closure values (p = 0.006); in particu-
                                    Left             10.9 ± 10.1 dB                        lar, the niche of the oval window particularly narrow was the
    Bilateral disease               No               11.9 ± 10.8 dB        0.096           anatomical anomaly that most negatively affected the post-
                                    Yes               10.1 ± 9.8 dB                        operative hearing outcome (p = 0.002). On the contrary, the
    Hospitalisation          Same-day surgery        10.6 ± 10.7 dB        0.670           occurrence of mild intraoperative complications, which were
                               Overnight stay         11.0 ± 9.9 dB                        reported in 13.5% of patients, did not play a significant role in
                                                                                           modifying postoperative ABG values (p = 0.179).
                                                                                           Finally, the average duration of the stapedotomy was
Table III. Mean postoperative ABG values according to the characteristics                  27.6 ± 8 min and, in particular, 38.8% of interventions last-
of the prosthesis (both material and diameter) and type of surgical approach               ed ≤ 20 minutes, 43.7% of the interventions lasted between
to the stapes.
                                                                                           21 and 30 minutes and only 17.5% of interventions lasted
                                              Post-Op ABG         P-value
                                                                                           more than 30 minutes.
    Prosthetic              Fluoroplastic (Teflon)    10.3 ± 10.1 dB        0.046*         Pearson’s correlation coefficient reported a significant
    material                      Titanium             12.1 ± 7.2 dB                       positive correlation between the lenght of surgery and
    Diameter of                    0.3 mm              12.1 ± 8.1 dB        0.096          postoperative ABG values (p = 0.002; r = .139) and a neg-
    prosthesis                     0.4 mm             10.3 ± 10.1 dB                       ative correlation between length of surgery and the EAC
    Surgical                    Conventional          11.2 ± 10.7 dB        0.140          diameter (r = -0.232; p < 0.001). Furthermore, the mean
    approach                    stapedotomy
                                                                                           duration of the stapedotomy was significantly longer when
                            Reverse stapedotomy        9.8 ± 10.4 dB                       the reverse technique was carried out (p = 0.034), when a
*
    statistically significant.
                                                                                           wider diameter of the piston was applied (p < 0.001), in
                                                                                           case of detection of anatomical anomalies (p < 0.001) and
                                                                                           in case of onset of intraoperative surgical complications
scores when fitting a wider piston than the 3mm diameter
                                                                                           (p = 0.014).
prosthesis (p = 0.042), there was no significant difference
in postoperative ABG values between Teflon or titanium
prostheses (p = 0.056).                                                                    Discussion
Pearson’s correlation coefficient did not show any signifi-                                The present study aimed to retrospectively review a large
cant correlation between postoperative ABG values and pa-                                  cohort of patients undergoing stapedotomy in order to as-
tients age (p = 0.093), EAC diameter (p = 0.100) and the                                   sess whether certain parameters could predict the extent of
same preoperative ABG values (p = 0.066).                                                  hearing improvement after primary surgery.
Unfortunately, it was possible to retrospectively trace the                                We set up a multicentre study by bringing together the sur-
intraoperative data relating to the finding of middle ear                                  gical series of two senior surgeons coming from the same


Table IV. Mean postoperative ABG values according to the intraoperative finding of middle ear anatomical anomalies or surgical complications.
                                                                                                             Post-Op ABG                    P-value
    Middle ear anatomical                                           None (77.7%)                                         9.8 ± 10.6 dB                 0 .006*
    anomalies                                            Narrow oval window niche (16.3%)
    (n = 480)                                                Obliterative footplate (2.9%)
                                                                                                                         13.1 ± 10.0 dB
                                                           Very thick posterior crus (2.1%)
                                                       Bulging intratympanic facial nerve (1%)
    Intraoperative                                                  None (86.5%)                                         10.8 ± 10.5 dB                 0.179
    complications                           Footplate fracture or excessive footplate mobilisation (7.9%)
    (n = 480)                                                 Excessive bleeding (3.3%)                                  9.1 ± 10.8 dB
                                                            Transient acute vertigo (2.3%)
*
    statistically significant.




                                                                                                                                                                   383
A. Albera et al.




surgical school and working in two reference hospitals for        ABG closure. Very few authors have previously presented
otosurgery: since no significant differences were found in        their results on same-day stapedotomy and only Ralli et al.,
surgical habits and on average preoperative and postopera-        although evaluating only 24 patients, recently confirmed
tive hearing thresholds between groups (Turin and Milan),         that the precision of this technique allows experienced sur-
all interventions were considered similar and therefore           geons to safely discharge patients a few hours after surgery
studied together.                                                 under local anaesthesia 19.
High surgical success rates were achieved in our series. The      In agreement with data in literature, we observed that
mean one-year postoperative ABG value on 581 patients             otosclerosis occurs about twice as frequently in women
was 10.8 dB, with an ABG closure ≤ 10 dB obtained in              compared to men (64 and 36%, respectively) 20,21 and in
62.3% of cases and therefore in line with the results re-         most cases affects both ears (72.5%, consistent with 75.6%
ported in literature, varying between 54% at 86% after sta-       mean value reported from Hueb et al. 22); nevertheless,
pedotomy, both microscopic and endoscopic assisted 11-14.         neither gender not unilateral or bilateral disease affected
Concerning diagnosis of otosclerosis, according to the            postoperative auditory outcomes. Similarly, age of
results of a recent systematic review by Wegner et al. 15, the    patients at time of surgery, although the older age is often
choice of both centres was to never perform a preoperative        considered a negative prognostic factor due to increased
high-resolution computed tomography (HRCT) as it was              cochlea frailty 10, did not significantly affect postoperative
considered unnecessary to confirm diagnosis and the               ABG values after stapedotomy.
surgical indication of those patients with clinical and           Among the parameters that were analysed in the present
audiometric findings strongly suggestive of otosclerosis.         study, there was also the diameter of the EAC, which has
A radiological evaluation was performed only in subjects          never been evaluated in relation to the postoperative hear-
with suspected further abnormalities of the middle ear and        ing outcome of the stapedotomy so far. This diameter,
who were therefore excluded from the study.                       whose most frequently encountered intraoperative values
All surgical procedures were correctly performed under            were 6 and 6.5 mm based on the ear speculum, has not
local anesthesia, thus reducing the potential serious com-        been shown to play a predictive role in postoperative ABG
plications of general anaesthesia with endotracheal intu-         closure, although a narrow EAC is undeniably recognised
bation 16 also allowing the patient to be discharged a few        as a parameter of difficulty as it limits the mobility and vis-
hours later in the absence of symptoms. With careful selec-       ibility of the surgeon.
tion of patients and adequate preoperative explanation of         Concerning the surgical approach to the stapes, all surger-
the surgical steps, we have been performing stapedotomy           ies were performed by means of a microdrill, which is con-
under local anaesthesia for about 10 years with high pa-          sidered safe and can even be used in patients with a small
tient compliance and satisfaction on the part of the operator     preoperative ABG without increasing the risk of sensori-
thanks to shorter surgical times and the possibility to test      neural hearing loss due to inner ear damage 23. Although
for subjective hearing improvement before concluding the          reverse stapedotomy was proposed by Fisch in 1980 to
surgical procedure. Only in a few cases (32 patients, 5.5%)       prevent excessive mobilisation of the platform or fractures
was it necessary to add mild conscious sedation with fen-         during crurotomy and, theoretically, achieve better hearing
tanyl 1 µg/kg and propofol in a target-controlled infusion        outcomes 6,7, we found no significant differences in post-
(TCI) due to sudden uncontrolled movements or discom-             operative ABG between conventional and the reverse sta-
forts like anxiety, dizziness, or excessive pain 17. The safety   pedotomy.
and efficacy of mild propofol anesthesia in middle ear sur-       Similar outcomes were reported in a recent review of the
gery was also reported by Thota et al., who reported shorter      literature, namely comparable audiological results between
recovery times, less nausea and vomiting in the immediate         techniques despite confirming better results in terms of
postoperative and improved patient satisfaction 18.               footplate and incus-associated complications with the re-
In our case series 70.7% of patients were hospitalised and        versal of surgical steps thanks to an increase in the stabil-
discharged the next morning, although this result is cer-         ity of the ossicular system 8. Although the choice of which
tainly influenced by the previous clinical protocol of the        technique to use is therefore always up to the surgeon and
two hospitals which required an overnight stay after almost       our data support this statement, it is important to emphasise
any type of otologic surgery. The possibility of carrying out     that the intraoperative detection of middle ear anomalies
same-day discharge after stapedotomy was fully introduced         such as a narrow oval window niche or a very thick poste-
only a few years ago and the data of this study confirm that      rior crus, in the case of SSS still intact, can limit the way
outpatient execution of this intervention allows to reduce        to space between facial nerve and SSS, and thus hinder the
the occupancy rate of beds in the ward without influencing        reverse stapedotomy.



384
                                                                    Prognostic factors influencing postoperative air-bone gap in stapes surgery




In our subseries of 480 patients for whom it was possible         materials 29, our data showed significantly better hearing
to obtain sufficient surgical data, the intraoperative iden-      outcomes with fluoroplastic pistons compared to titanium
tification of middle ear anomalies, which was highlighted         ones, with a mean postoperative ABG value lower by 2 dB
in 22.3% of subjects, was demonstrated to significantly           when using those in Teflon. We are convinced that a piston
worsen postoperative ABG values. In particular, the very          in fluoroplastic material, once sufficient experience in in-
narrow oval window niche, whose incidence according               sertion has been achieved, guarantees good results by vir-
to literature ranges from 2.6% to 31% 12,24 and which was         tue of intrinsic characteristics such as excellent chemical,
detected in 16.3% of our patients, was correlated with an         biological and electrical inertness, high thermal stability
ABG closure even higher than 4 dB compared to normal              and an elastic memory which avoids excessive crimping of
subjects. On this topic, Vincent confirmed our results by         the Teflon loop around the long process of the incus. Sim-
having analysed more than 3000 stapedotomies, reporting           ilar conclusions were also reported by Durko et al., who
that a successful outcome may be expected although with           consider this material as the best option for stapedotomy 30.
evident effect of middle ear abnormalities on the success         The occurrence of mild intraoperative surgical complications
rate of this surgery 24.                                          has been reported in 13.5% of surgeries and among them, the
The duration of surgery is another intraoperative param-          most frequent were an excessive footplate mobilisation or
eter that has been correlated with postoperative auditory         a footplate fracture (8%); however, the piston was correctly
outcomes: our results showed that the shorter the opera-          placed in all patients and we never had to use gelfoam or fat
tive time, the better the final result in terms of ABG clo-       as sealing to prevent perilymph leakage. Another frequent
sure as very good outcomes (ABG lower than 10 dB) were            intraoperative complication in our series was significant
obtained in interventions that lasted less than 20 minutes.       bleeding, which at times made the placement of the pros-
The operative time, as expected, was found to be signifi-         thesis very challenging and which Demir reported was sig-
cantly longer in case of intraoperative findings of anatomi-      nificantly lower in cases of incisions with cautery compared
cal anomalies of the middle ear or in case of minor surgical      to cold instruments, with no difference in postoperative pain
complications. However, stapedotomy can be also techni-           and in wound healing 31. Finally, the last quite infrequent
cally challenging due to anatomic variations in size, shape,      complication highlighted among our patients was the onset
or irregularity of the EAC and, in fact, in our series, the       of transient acute vertigo, which is reported in the literature
surgical time was significantly increased parallel to the re-     in up to 77% of cases 31, likely due to excessive injections
duction of the EAC diameter. Although the final auditory          of local anaesthetic in the EAC prior to tympanomeatal flap
result did not ultimately change in relation to the latter pa-    elevation and sometimes due to perilymphatic displacement
rameter, surgical delay described is likely to be related to      during the positioning of the piston. Despite these unpleasant
the surgeon’s need to perform a larger atticotomy to get a        occurrences, the onset of intraoperative surgical complica-
correct view of the SSS.                                          tions did not play a significant role in modifying the postop-
Since the development of stapes surgery in 1956, a large          erative hearing outcome. However, the strengths of this case
number of prostheses have been used and both size and ma-         series were the focus on a large sample (almost 600 patients)
terial have always been the focus of research for improve-        with medium-term audiological follow-up (at least 1 year)
ment. Looking in the literature, the piston diameter varies       and the completion of all surgeries by only two highly ex-
from 0.3 mm up to 0.8 mm 25. Experimental studies based           perienced surgeons, thus making unlikely that interpersonal
on mathematical and anatomical models have shown a trend          differences in surgical approach or expertise had an influ-
towards better auditory outcomes of stapedotomy in case of        ence on hearing outcomes.
larger diameter prostheses 26,27, since it is reasonable that
an extremely narrow piston will not transmit enough sound
energy into the vestibule due to smaller volume displace-
                                                                  Conclusions
ment. In contrast, a recent systematic review by Wegner           In conclusion, the present multi-centre retrospective study,
et al. concluded that there is insufficient evidence to sup-      including 581 patients undergoing primary stapedotomy
port the superiority of a larger-diameter piston compared         for otosclerosis, confirms the safety and efficacy of this
to a smaller-diameter one for primary stapedotomy 28 and,         intervention performed under local anaesthesia, with ex-
indeed, our results also did not show significantly different     cellent auditory results in terms of postoperative blood gas
postoperative ABG values between 0.3 mm and 0.4 mm di-            analysis. Furthermore, the study suggests some predictors
ameter prostheses. Furthermore, although Faramarzi et al.         of failure of the stapedotomy (postoperative ABG > 10 dB)
reported, in a recent randomised clinical trial, similar short-   such as the material of the prosthesis, the length of surgery
term auditory results in the use of prostheses of different       and intraoperative detection of anatomical abnormalities



                                                                                                                                         385
A. Albera et al.




such as a narrow oval window niche. Therefore, our find-                        10
                                                                                     Albera R, Giordano L, Rosso P, et al. Surgery of otosclerosis in the
                                                                                     elderly. Aging Clin Exp Res 2001;13:8-10. https://doi.org/10.1007/
ings can encourage the development of increasingly effec-                            BF03351487
tive surgical approaches and provide the surgeon with very                      11
                                                                                     de Bruijn AJ, Tange RA, Dreschler WA. Efficacy of evaluation of
useful preoperative or intraoperative information on the                             audiometric results after stapes surgery in otosclerosis. I. The effects
likelihood of stapedotomy success.                                                   of using different audiologic parameters and criteria on success
                                                                                     rates. Otolaryngol Head Neck Surg 2001;124:76-83. https://doi.
                                                                                     org/10.1067/mhn.2001.111601
Conflict of interest statement                                                  12
                                                                                     Daniel RL, Krieger LW, Lippy WH. The other ear: findings and re-
The authors declare no conflict of interest.                                         sults in 1,800 bilateral stapedotomies. Otol Neurotol 2001;22:603-
                                                                                     607. https://doi.org/10.1097/00129492-200109000-00007
Funding                                                                         13
                                                                                     Babighian GG, Albu S. Failures in stapedotomy for otosclero-
                                                                                     sis. Otolaryngol Head Neck Surg 2009;141:395-400. https://doi.
This research did not receive any specific grant from fund-                          org/10.1016/j.otohns.2009.03.028
ing agencies in the public, commercial, or not-for-profit                       14
                                                                                     Bianconi L, Gazzini L, Laura E, et al. Endoscopic stapedotomy: safe-
sectors.                                                                             ty and audiological results in 150 patients. Eur Arch Otorhinolaryn-
                                                                                     gol. 2020;277:85-92. https://doi.org/10.1007/s00405-019-05688-y
Author contributions
                                                                                15
                                                                                     Wegner I, van Waes AMA, Bittermann AJ, et al. A systematic re-
                                                                                     view of the diagnostic value of CT imaging in diagnosing oto-
All authors contributed to the study conception and design.                          sclerosis. Otol Neurotol 2016;37:9-15. https://doi.org/10.1097/
Material preparation, data collection and analysis were                              MAO.0000000000000924
performed by FP, RAl, GR, RAn and AC. AA wrote the                              16
                                                                                     Taheri A, Hajimohamadi F, Soltanghoraee H, et al. Complications of
first draft of the manuscript and other authors provided                             using laryngeal mask airway during anaesthesia in patients undergo-
                                                                                     ing major ear surgery. Acta Otorhinolaryngol Ital 2009;29:151-155.
critical revision.                                                              17
                                                                                     De Siena L, Albera R, Pallavicino F, et al. Monitored Anesthesia care
                                                                                     with target controlled infusion (TCI) in myringoplasty. Otorinolarin-
Ethical consideration                                                                gologia 2013;63:179-184.
Written informed consent to be inserted in our database                         18
                                                                                     Thota RS, Ambardekar M, Likhate P. Conscious sedation for middle
                                                                                     ear surgeries: a comparison between fentanyl-propofol and fentanyl-
was obtained by each patient and the protocol study, car-                            midazolam infusion. Saudi J Anaesth 2015;9:117-121. https://doi.
ried out according to the 1964 Helsinki Declaration and its                          org/10.4103/1658-354X.152818
later amendments or comparable ethical standards, was ap-                       19
                                                                                     Ralli G, Mora R, Nola G, et al. Day-case stapedotomy: is it a viable
proved by the Institutional Review Board of the University                           option? Acta Otolaryngol 2012;132:21-26. https://doi.org/10.3109/00
                                                                                     016489.2011.619572
of Turin (protocol n. 0058243, May 2021).                                       20
                                                                                     Emmett JR. Physical examination and clinical evaluation of the pa-
                                                                                     tient with otosclerosis. Otolaryngol Clin North Am 1993;26:353-357.
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Supplementary material                                                       performed before placement of the prosthesis: disarticula-
                                                                             tion of the incudostapedial joint (ISJ), posterior crurotomy,
                                                                             fracture of the anterior crus towards the promontory and
Detailed description of the surgical steps
                                                                             subsequent removal of the stapes suprastructure (SSS). In
of the stapedotomy
                                                                             contrast, the reverse stapedotomy originally proposed by
All surgical procedures were always performed by the
                                                                             Ugo Fisch was carried out in all other patients, with an
same senior surgeon in the two clinical centres respectively
and every patient was submitted to stapedotomy under lo-                     early and safer perforation of the footplate followed by in-
cal anaesthesia.                                                             sertion of the piston before disarticulation of the ISJ and
In particular, a combination of adrenaline (1 in 15.000) and                 removal of the SSS.
mepivacaine (3%) as the local anaesthetic agent was used,                    Similarly to the surgical approach, even as regards the pros-
injected anteriorly at the 3 o’clock position, inferiorly at                 thesis were used two different types depending on the sur-
the 6 o’clock position and posteriorly at the 9 o’clock po-                  geon’s preference and habit: a fluoroplastic piston (Teflon)
sition of the external meatus. The approach to the middle                    with a 0.3- or 0.4 mm shaft diameter, and a titanium soft
ear was performed by means of a posterior tympanomeatal                      clip piston with a 0.4 mm shaft’s diameter. All prostheses
flap and, if necessary, a small atticotomy was carried out                   considered in the study had a 4.5 mm length.
by means of a curette in order to expose the oval window                     The malleus neck was always probed at the end of the pro-
region.                                                                      cedure to rule out any ossicular chain fixation. Finally, the
Then, according to the surgeon’s preference, the stapes ap-                  tympanomeatal flap was repositioned and a ciprofloxacin
proach was performed in two different ways. In some pa-                      0.3%/dexamethasone 0.1% soaked Merocel was placed in
tients, the conventional surgical steps of stapedotomy were                  the external acoustic meatus.




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