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\begin{document}

\title{The biofilm characteristics and management of skin flap infection
following cochlear implantation: A prospective study from 2001 to 2021}



\author[1]{Xi-Hang Chen}%
\author[2]{Yuqing Chen}%
\author[1]{Rong Zhang}%
\author[1]{Shengnan Ye}%
\author[3]{Zhongyang Lin}%
\author[1]{Chang Lin}%
\affil[1]{The First Affiliated Hospital of Fujian Medical University}%
\affil[2]{The First Affiliated hospital of Fujian Medical University }%
\affil[3]{The First affiliated hospital of Fujian Medical University}%


\vspace{-1em}



  
  \date{May 20, 2024}


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\selectlanguage{english}
\begin{abstract}
Objective: To assess the clinical features and the management of skin
flap infection (SFI) following cochlear implantation (CI) and to
characterize the biofilm features by the scanning electron
microscopy.Setting: The study was conducted at a tertiary care
center.Participants: A total of 1,251 patients receiving CI in the First
Affiliated Hospital of Fujian Medical University between August 2001 and
March 2021 were enrolled. Scanning electron microscopy was utilized for
characterizing the etiology of infection. Main outcome measures: A
proposed stratification system was applied to optimize treatments for
post-operation flap infection.Results: After CI, SFI was reported in 16
patients (1.28\%) and patients under 18-year-old were more prone to flap
infection. Staphylococcus Aureus was found to be the most common
bacterial culprit for flap infection, with 6 cases explored in this
group (6/16, 37.5\%). Bacterial biofilm was observed within the
jelly-like substance on the surface of CI equipment of SFI patients. A
two-stage stratification was proposed for optimizing the treatment
schemes. Conservative therapy was recommended for stage I cases while
surgical treatment was the preferred method for stage II
patients.Conclusions: Pediatric patients are more susceptible to SFI
after CI. The formation of bacterial biofilm may be the vital cause of
SFI. The proposed stratification can facilitate the management of SFI.%
\end{abstract}%



\sloppy


\textbf{Abstract}

\textbf{Objective} To assess the clinical features and the management of
skin flap infection (SFI) following cochlear implantation (CI) and to
characterize the biofilm features by the scanning electron microscopy.

\textbf{Setting} The study was conducted at a tertiary care center.

\textbf{Participants} A total of 1,251 patients receiving CI in the
tertiary Hospital between August 2001 and March 2021 were enrolled.
Scanning electron microscopy was utilized for characterizing the
etiology of infection.

\textbf{Main outcome measures} A proposed stratification system was
applied to optimize treatments for post-operation flap infection.

\textbf{Results} After CI, SFI was reported in 16 patients (1.28\%) and
patients under 6-year-old were more prone to flap infection.
Staphylococcus Aureus was found to be the most common bacterial culprit
for flap infection, with 6 cases explored in this group (6/16, 37.5\%).
Bacterial biofilm was observed within the jelly-like substance on the
surface of CI equipment of SFI patients. A two-stage stratification was
proposed for optimizing the treatment schemes. Conservative therapy was
recommended for stage I cases while surgical treatment was the preferred
method for stage II patients.

\textbf{Conclusions} Pediatric patients are more susceptible to SFI
after CI. The formation of bacterial biofilm may be the vital cause of
SFI. The proposed stratification can facilitate the management of SFI.

\par\null

\textbf{Keywords} Cochlear implant; biofilm; infection; scanning
electron microscope; management

\textbf{Key Points}

\selectlanguage{ngerman}· The study proposes a system to stratify the SFI treatments, which may
optimize individual treatment strategies and reduce hospitalization and
cost for all patients.

· Bacterial biofilm is found in the receiver-stimulator area of SFI
after cochlear implantation.

· A treatment flow is conceived to address the SFI patients more
accurately.

· The skin integrity of the infectious area indicates different regimens
toward SFI after the implantation.

\textbf{1.Introduction}

Cochlear implantation (CI) is considered as a well-defined and safe
surgical procedure allowing hearing rehabilitation of patients with
severe or profound hearing loss\textsuperscript{1,2} . With the advance
and popularization of newborn hearing screening, bilateral severe or
profound sensorineural hearing loss can be detected earlier. CI surgical
technique has progressed strongly over the past decade, with operations
increasing and postoperative complications decreasing. Postoperative
skin flap infections, a recognized complication of cochlear implant
procedure, may induce significant morbidity\textsuperscript{2,3}.

Generally, CI postoperative infections have been classified into the
minor or major complications and also can be divided into early or
delayed infections according to duration\textsuperscript{4,5}. Skin flap
infection (SFI) remains one of the most challenging and devastating
modes of failure following cochlear implants, which is difficult for the
otologists to predict and may ultimately lead to device removal, despite
rigorous medical and surgical endeavors to eradicate the infections.

To date, however, few studies have compared the efficiency between
conservative and surgical treatments. The current study focused on the
bacterial biofilm formation-related infections of cochlear implantation.
It aimed to investigate frequency and efficacy management of
postoperative infections and to identify the potential causes of the
refractory SFI.

\textbf{2.Methods}

\textbf{Design}

Each included patient gave their informed consent to participate in the
study. The study protocol was approved by the ethics committee and
institutional review board of the hospital.

All 16 SFI patients who developed postoperative infection received
immediate conservative treatment or surgical intervention when the
conservative treatment was proven ineffective.

\textbf{Data availability statement}

The data that support the findings of this study are available from the
corresponding author upon request.

\textbf{Setting}

The study was conducted at a tertiary care center.

\textbf{Participants}

Retrospectively reviewed were the medical records of 1,251 patients who
underwent CI to treat profound hearing loss between August 2001 and
March 2021.All patients suffered severe or very severe bilateral
sensorineural hearing loss (HL, defined as hearing threshold
\textgreater{} 70 dB HL). Before the initial CI, assessments were
conducted of acoustic impedance, auditory brainstem response, distortion
product otoacoustic emissions, transient evoked otoacoustic emissions,
auditory steady state response. Middle ear high-resolution CT (HRCT) and
inner ear magnetic resonance hydrography were performed to rule out the
deformity in middle and inner ears, middle ear mastoiditis, tympanic
effusion, or other infections before operation. Brain MRI examination
was conducted to reveal potential white matter lesions and CI was
considered for those cases with mild and non-progressive white matter
lesions.

\textbf{Main outcome measures}

Patients with postoperative infection were treated immediately with
ceftriaxone sodium and subsequently with pathogen-specific antibiotics
on the basis of the culture results. The pus was drained when the
formation was localized in the subcutaneous tissue.

Patients irresponsive to conservative treatment received revision
surgery or re-implantation surgery if the revision surgery failed. The
former consisted of cleaning up granulation tissue in the bone groove,
rinsing equipment with 3\% hydrogen peroxide, normal saline, and 1\%
iodophor repeatedly, finally reverting suitable temporal muscle covering
the groove. The latter involved explanting equipment but saving the
electrode in cochlear, and implanting a new cochlear in the opposite
side. Both surgical treatments were followed by a 3-day administration
of ceftriaxone sodium.

The jelly-like biofilm on the surface of receiver/stimulator was rinsed
with phosphate buffered saline (PBS) 3 times (1 minute per time), soaked
in 1\% osmic acid solution at \textless{} 4\selectlanguage{english} for 2 h. Then, the samples
were sequentially dehydrated in 30\%, 50\%, 70\%, 85\%, 95\%, and 100\%
ethanol for 15 minutes per time, respectively. After the
CO\textsubscript{2} critical dry point and correcting the position and
orientation, samples were placed on the platform for sputter-coated with
gold in a vacuum condition and examined in a high vacuum of 20kv under a
scanning electron microscope (SEM; American FEI company, model Quanta
450). Multiple bacterial biofilm SEM areas of each specimen were
observed with multiple magnifications (50\selectlanguage{english}~10000 times).

The formation of bacterial biofilms was diagnosed when the images met
the three criteria: dense

accumulation of bacterial cells, the presence of a polysaccharide matrix
around bacterial cells, and firm surface binding\textsuperscript{6}.

All statistical tests were performed using SPSS software (version 26.0;
SPSS Inc., Chicago, IL, USA). The differences of categorical variables
were assessed using Fisher's test as appropriate including sex, age,
implant side, different regimens and outcomes. \emph{P} -values of less
than 0.05 indicated statistical significance. All statistical tests were
two-sided.

\textbf{3 Results}

A total of 1,251 CI cases (739 males, 59.05\% and 512 females, 40.95\%)
were reviewed (Table 1), with CI performed on 898 right ears (71.79\%),
337 left ears (26.90\%), and 16 bilateral ears (1.28\%); surgery age
ranged from 10 months to 63 years old, with a mean age of 7.3 years old
and a median age of 3.5 years old. All cases were operated by one
surgeon in our institution between August 2001 and March 2021.

A total of 16 SFI patients were reported from the whole CI patient
cohort (1.28\%, 8 males and 8 females), who were all under 6 years old
(\emph{p} \textless{} 0.05), with a mean age of 3.09 years old (Table
2). The onset of SFI symptoms ranged from 20 days to 3 years after the
implantation, affecting 14 right ears (87.5\%), 1 left ear (6.25\%) and
1 bilateral ear (6.25\%). Gender were not significantly different.
Laterality was significant difference (\emph{p} \textless{} 0.05), but
paired statistics revealed no significance (\emph{p} \textgreater{} 0.05
for all three paired statistics).

Of the 16 children, three were cured by conservative methods (3/16,
18.75\%) and thirteen by surgery (13/16, 81.25\%). In the latter group,
three patients were cured by revision surgery (3/13, 23.08\%) and ten
failed to be remedied by initial revision surgery but cured by
subsequent re-implantation surgery (10/13, 76.92\%) (\emph{p}\textless{}
0.05).

In all infectious symptoms (Table 3), skin redness was reported in 2
patients (2/16, 12.5\%), one cured by conservative method and the other
by revision surgery; subcutaneous pus formation was found in 4 patients
(4/16, 25\%), two cured by conservative method and two by
re-implantation surgery; punctured pus in 7 patients (7/16, 43.75\%),
one by revision surgery (1/7, 14.3\%) and 6 by re-implantation surgery
(6/7, 85.7\%); the implant was exposed in 3 patients and rescued by
re-implantation surgery (100\%).

The results indicated no significant differences in therapeutic efficacy
between conservative and surgical treatments in skin redness or
subcutaneous pus formation but noticeable significance for punctured pus
when re-implantation was compared with either revision surgery or
conservative treatment (\emph{p} \textless{} 0.05, respectively). The
revision surgery was not effective regardless of the clinical
manifestations (Figure1).

On the images by scanning electron microscopy (Figure 2),
microorganisms, consistent with \emph{Staphylococcus} , and matrix were
found over the surface of the stimulator-receiver, but not on the
electrode. Large mesh can be seen in the middle of the grid.

Granulation tissue appeared in the bone groove and surrounding the
cochlear equipment, foam-like tissue cells was visualized in the
granulation tissue by the hematoxylin-eosin staining, which indicates
that the symptoms of SFI cases are chronic inflammation reaction (Figure
2).

\textbf{4 Discussion}

Postoperative infection is one of the most common
complications\textsuperscript{5,7} after cochlear implantation and
conservative treatments are suggested to be primary and first-line
regimens. For post-CI infection, a routine procedure may sequentially
involve antibiotic treatments, pus puncture, revision surgery, and
re-implantation\textsuperscript{8}, which does not take heed of the
specific clinical postoperative manifestations of CI and may cause
repeated SFI. Therefore, a more accurate and efficient staging system is
needed.

In the current study, the integrity of local skin is a significant index
that greatly influences the diagnosis and efficacy of treatments for
post-CI infection. Before the skin ruptures, oral or intravenous
antibiotic therapy was prescribed. Puncture and etiology-guided
antibiotics were administered after abscess was formed. Once the
integrity of the skin flap was breached, the majority of patients were
cured by re-implantation. These findings suggest that for all SFI cases,
the integrity of skin flap can serve as a facilitating index for
stratifying the clinical manifestations (Figure 3):

Stage I: Complete skin with redness and swelling or subcutaneous pus
formation that can be properly addressed by conservative treatment.

Stage II: Ruptured pus formation or exposed implant that can be remedied
by re-implantation.

Of note, the revision surgery was attempted to prevent the cochlear
equipment from explant, which proved to be ineffective at any stage in
the current study. Thus, re-implantation plays an important role in the
prognosis of patients at stage II.

This stratification system only targets the post-CI SFI, whose bacterial
culture was a positive result. The skin injury, from antenna pressure
stratified by the National Pressure Ulcer Advisory
Panel\textsuperscript{5} and foreign body response including knot and
device, is not involved in the current stratification system. The
similar symptoms of infection, antenna pressure, and foreign body
response may pose some confusion in choosing a correct system, which
needs a more comprehensive study.

It is worth mentioning that in all cases of post-CI infection, no
obvious malfunctions were reported in cochlear implants, which suggests
that post-CI infection only affects the bone groove and skin flap where
the receiver/stimulator is located while the cochlear electrodes are
safe. But some studies have reported that the function of the device was
affected after SFI\textsuperscript{9,10}, which is related to persistent
infection and the hypersensitivity caused by the
infection\textsuperscript{9}. Therefore, such complications should also
be considered.

The rate of postoperative infection in the current study is similar to
that of several previous studies, within the range of
1.6\%\textasciitilde{}8.2\%\textsuperscript{11}. The incidence of
complications has remained stable for many
decades\textsuperscript{5,12}, no matter how experienced the surgeon is
with cochlear implantation. Staphylococcus and pseudomonas are
recognized as the most easily-colonized bacteria on the surface of
implants in most studies\textsuperscript{5,8}. But for all cases of
infection in our center, conservative treatment, even guided by culture
results, cannot eradicate SFI thoroughly, which may relapse in weeks or
months.

We found a jelly-like substance on the flap-covered side, which
concentrated in the center and scattered around, and observed a
bacterial biofilm under the scanning electron microscope. We suspect
that antibiotic-resistant bacterial infection may be one of the
recurrent reasons, while the formation of biofilm has a greater impact
on the recurrent SFI.

Biofilm is easily found on the surface of the device, and most
distributed in the center of the device\textsuperscript{9}. This may be
due to the absence of a silicone package over the magnetic pole in the
center of the equipment, which indicates that the design and material
improvements are needed for the receiver-stimulators so as to reduce the
probability of infection after CI. Tea tree oil (the essential oil of
Melaleuca) was found to remove methicillin-resistant Staphylococcus
aureus from the surface of the implants\textsuperscript{13-15}.
Bioactive glass particles can inhibit the mature bacterial biofilm on
the surface of the cochlear equipment\textsuperscript{16}. But the
availability and safety of these materials await further exploration.

Bacterial biofilm is a complex ecosystem. Multi-microbial aggregates
composed of a variety of bacteria are embedded in the exopolysaccharides
(EPS), mainly composed of polysaccharides, protein-nucleic acids, and
lipids\textsuperscript{17}. Antibiotics only inhibit the planktonic
bacteria released by the biofilm, but fail to eliminate the
biofilm\textsuperscript{18}. Bacteria are generally located in the
middle layer of the membrane and are wrapped with the
EPS\textsuperscript{19}, which makes it difficult for antibiotics to
penetrate every layer of the biofilm and clean bacteria up. On the other
hand, the implanted cochlear may provide acquired conditions for the
biofilm to resist the environmental changes and the human immune
system\textsuperscript{20}, which usually terminates when the antenna is
removed from the body by procedure\textsuperscript{18}. This complexity
may explain the recurrent bacterial infection and the irresponsive
antibiotic treatment.

In the revision surgery of SFI, the surface of the receiver-stimulator
was covered with the jelly-like biofilm, which was similar to the
substance found by Jiri et al\textsuperscript{21}. On the electron
microscopic images at 5000 times, a morphology of typical dense network
can be observed in the bacterial biofilms, with pipe-shaped channels,
which is in line with the morphology reported by Gi Jung Im et
al\textsuperscript{9}.

How to eradicate biofilm is a challenging handicap. We managed to remove
the granulation around the implant and soaked the receiver-stimulator of
the implant with 1.5\% hydrogen peroxide and the aqueous solution of
betadine for 30 minutes as reported by Jiri Skrivan et
al.\textsuperscript{21}, and covered with part of temporalis to protect
the equipment, but the results were negative. Mohnish Grover et al.
chose to re-grind a new bone groove which was located away from the
original bone groove and infected area to place the
receiver\textsuperscript{3}. This is a method that can be used as a
reference, but it will damage the skull of patients. The original place
with a weak skull is vulnerable to intracranial trauma when hit by
force.

Aseptic enhancement during the initial surgery can reduce the patients'
pain and preserve the expensive devices via inhibiting the formation of
biofilm. The CI surgery can only commence after the complete curation of
inflammation in the ears\textsuperscript{5}. Preoperative skin
preparation in the operating room significantly reduces the
postoperative infection rate\textsuperscript{22,23}, including waxing
the patient's hair a few days before CI, lavaging the patients' external
auditory canal with 70\% alcohol daily with 0.5\% chlorhexidine, and
wiping the skin of the surgery area\textsuperscript{5}.

The position of CI incision also impacts the infectious rate. Kabelka et
al. found that the postoperative SFI rate of the incision behind the ear
was about 15 times lower than that of the incision in the
ear\textsuperscript{5}. Gawecki et al. found that when the short C-type
incision behind the ear was compared with the long incision, the
infection rate dropped from 2.43\% (11/452) to 1.28\%
(8/624)\textsuperscript{5}. In our cohorts, all cases were operated with
short C-type incision behind the ear and the overall infectious rate was
lower than in many institutions\textsuperscript{11}.

Ceftriaxone sodium injection is generally used as a preventive
medication for 3 days after the initial surgery. Garcia Valdecasas et
al. reported that ceramic-coated cochlear implants such as MED-EL
implants and Cochlear Nucleus and Advanced Bionics implants employ
titanium silicon for the artificial coating, using ceftriaxone sodium
before surgery and clarithromycin after surgery, in which the
postoperative infection rate is significantly lower than that of
ceftriaxone sodium alone\textsuperscript{5}. This can be a different
inspiration. Lisa Kirchhoff et al.\textsuperscript{24} tried to utilize
bioactive glass (BAG) of type S53P4 as a promising tool for the
reduction of biofilm formation.

\textbf{5. Conclusion}

In summary, with the reviewed clinical data of the enrolled cohort
patients, this study proposes a staging system to stratify the treatment
of SFI, which may optimize individual treatment strategies and reduce
hospitalization and cost for all patients. The bacterial etiological
analysis reveals that the presence of bacterial biofilm contributes to
the recurrent CI infections, which can be cured by re-implantation.
Given the large cohort of CI patients and infectious risk factors
analyzed, younger patients with CI surgery are at a high risk of
refractory repeated infection, indicating that additional efficient
follow-up strategies should be implemented for the underaged.

\textbf{References}

1. Farinetti A, Ben Gharbia D, Mancini J, Roman S, Nicollas R, Triglia
JM. Cochlear implant complications in 403 patients: comparative study of
adults and children and review of the literature. \emph{Eur Ann
Otorhinolaryngol Head Neck Dis.} 2014;131(3):177-182.

2. Olsen LB, Larsen S, Wanscher JH, Faber CE, Jeppesen J. Postoperative
infections following cochlear implant surgery. \emph{Acta
Otolaryngol.}2018;138(10):956-960.

3. Grover M, Sharma S, Kataria T, Samdani S, Agarwal S, Singh SN. Soft
tissue reactions following cochlear implantation. \emph{Eur Arch
Otorhinolaryngol.} 2019;276(2):343-347.

4. Filipo R, D'Elia C, Covelli E, et al. Haematoma after cochlear
implantation: management of a minor complication. \emph{Acta
Otolaryngol.} 2010;130(1):108-113.

5. Vijendren A, Borsetto D, Barker EJ, et al. A systematic review on
prevention and management of wound infections from cochlear
implantation. \emph{Clin Otolaryngol.} 2019;44(6):1059-1070.

6. Elzayat S, Nosair N, Ghazy AA, Abdulghaffar IA. Otitis media with
effusion is not a sterile inflammatory process: scanning electron
microscope evidence. \emph{Eur Arch Otorhinolaryngol.} 2020.

7. Qin F, Li W, Qiu J, Zhang L, Zhong M. After cochlear implantation:
Complications related to flap around implants. \emph{J
Otol.}2016;11(4):198-201.

8. Patrick JA, James CL, Robert AB. Bacterial Biofilms May Contribute to
Persistent Cochlear Implant Infection. \emph{Otology \&
Neurotology.}2004;25:953-957.

9. Im GJ, An YS, Choi J, Song JJ, Chae SW, Jung HH. Analysis of
Bacterial Biofilms on a Cochlear Implant Following Methicillin-Resistant
Staphylococcus Aureus Infection. \emph{J Audiol
Otol.}2015;19(3):172-177.

10. Del Pozo JL. Biofilm-related disease. \emph{Expert Rev Anti Infect
Ther.} 2018;16(1):51-65.

11. McAllister K, Linkhorn H, Gruber M, Giles E, Neeff M. The Effect of
Soft Tissue Infections on Device Performance in Adult Cochlear Implant
Recipients. \emph{Otol Neurotol.} 2017;38(5):694-700.

12. Hsieh HS, Lee CY, Wu HP, Zhuo MY, Hwang CF. Pressure ulcers and skin
infections after cochlear implantation: A delayed yet serious
issue.\emph{Int J Pediatr Otorhinolaryngol.} 2020;138:110241.

13. Farnan TB, MRCS., MCCALLUM J, et al. Tea tree oil: in vitro efficacy
in otitis externa. \emph{The Journal of Laryngology \&
Otology.}2005;119:198-201.

14. Brady A, Loughlin R, Gilpin D, Kearney P, Tunney M. In vitro
activity of tea-tree oil against clinical skin isolates of
meticillin-resistant and -sensitive Staphylococcus aureus and
coagulase-negative staphylococci growing planktonically and as
biofilms.\emph{J Med Microbiol.} 2006;55(Pt 10):1375-1380.

15. Brady AJ, Farnan TB, Toner JG, Gilpin DF, Tunney MM. Treatment of a
cochlear implant biofilm infection: a potential role for alternative
antimicrobial agents. \emph{J Laryngol Otol.} 2010;124(7):729-738.

16. Hoing B, Kirchhoff L, Arnolds J, et al. Bioactive Glass Granules
Inhibit Mature Bacterial Biofilms on the Surfaces of Cochlear
Implants.\emph{Otol Neurotol.} 2018;39(10):e985-e991.

17. Christine MD, Payam F, John MC, Annemarie B, Rahwa T, Abby L G.
Patients with familiar adenomatous polyposis harbor colonic biofilms
containing tumorigenic bacteria. \emph{Science.} 2018;359:592-597.

18. Costerton JW, Stewart PS, Greenberg EP. Bacterial biofilms: a common
cause of persistent infections. \emph{Science.}1999;284(5418):1318-1322.

19. Low KE, Howell PL. Gram-negative synthase-dependent
exopolysaccharide biosynthetic machines. \emph{Curr Opin Struct
Biol.}2018;53:32-44.

20. Cevizci R, Duzlu M, Dundar Y, et al. Preliminary results of a novel
quorum sensing inhibitor against pneumococcal infection and biofilm
formation with special interest to otitis media and cochlear
implantation. \emph{Eur Arch Otorhinolaryngol.} 2015;272(6):1389-1393.

21. Skrivan J, Drevinek P. A case report of a cochlear implant infection
- A reason to explant the device? \emph{Cochlear Implants
Int.}2016;17(5):246-249.

22. Richard S, Benedict MR. Wound infections after preoperative
depilatory versus razor preparation. \emph{Am J Surg.} 1971;121:251-254.

23. Alicia JM, Teresa CH, Michele LP. Guideline for prevention of
surgical site infection. \emph{Hospital Infection Control Practices
Advisory Committee.} 1999;27(2):97-132.

24. Kirchhoff L, Arweiler-Harbeck D, Arnolds J, et al. Imaging studies
of bacterial biofilms on cochlear implants---Bioactive glass (BAG)
inhibits mature biofilm. PLOS One. 2020 Feb 21;15(2): e0229198.\selectlanguage{english}
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\verb`Tab.1.docx`  available at \url{https://authorea.com/users/732187/articles/710722-the-biofilm-characteristics-and-management-of-skin-flap-infection-following-cochlear-implantation-a-prospective-study-from-2001-to-2021}

\textbf{Hosted file}

\verb`Tab.2.docx`  available at \url{https://authorea.com/users/732187/articles/710722-the-biofilm-characteristics-and-management-of-skin-flap-infection-following-cochlear-implantation-a-prospective-study-from-2001-to-2021}

\textbf{Hosted file}

\verb`Tab.3.docx`  available at \url{https://authorea.com/users/732187/articles/710722-the-biofilm-characteristics-and-management-of-skin-flap-infection-following-cochlear-implantation-a-prospective-study-from-2001-to-2021}

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