Keywords
tympanoplasty - endoscopes - microsurgery - otologic surgical procedure - natural
orifice endoscopic surgery
Introduction
Endoscopes were used for the first time in the context of otorhinolaryngology in cholesteatoma
removal procedures and myringoplasties.[1] They are currently used as a primary or auxiliary device in a variety of middle
ear procedures, including tympanoplasty, ossiculoplasty, and cochlear implant surgery.[2]
[3]
[4] The microscopic technique is still widely used, since it has considerable advantages,
such as stereoscopic vision together with amplified surgical vision, and the possibility
of using the two hands of the surgeon to handle the equipment, facilitating the removal
of blood from the operative field during the procedures.[5] However, characteristics of microscopes such as narrow-angle vision and straight
field of view do not allow a wide observation of more hidden areas of the middle ear,
such as the facial recess, the attic, the epitympanum, and the tympanic sinus, requiring
the performance of procedures such as bone curettage or anterior canaloplasty, in
addition to external incisions.[6]
[7] Endoscopes, especially angular ones, guarantee direct access to these hidden areas,[8] besides offering considerable benefits, such as panoramic view, high definition
and magnification without loss of resolution, simplicity in obtaining zoom, and less
chance of incisions or perforations, given that the light source is located at the
tip of the endoscope itself.[9] In addition, the endoscopic approach, being minimally invasive, can guarantee more
satisfactory results for patients[10] and a better chance of education for trainees during the procedures.[11] Therefore, it is still important to elucidate and clarify the relationship of relative
benefits and disadvantages between the two techniques. In the present review, it is
also discussed whether there would be superiority in the choice of any of them, to
allow a more adequate choice for the surgeon, considering their technical experience,
and for the patient, taking into account their medical indication and adequacy to
the results and peri- and postoperative implications. The aim of the present study
was to compare the benefits and disadvantages of each technique, endoscopic and microscopic,
applied in tympanoplasty.
Literature Review
Research Protocol
The present systematic review was developed according to the Preferred Reporting Items
for Systematic Reviews and Meta-Analyses (PRISMA) recommendations.[12] A PRISMA flow diagram was used to describe the flow of information throughout the
various phases of the systematic review. The present study used qualitative methods
to examine the results.
In the present study, the main question was to evaluate what were the benefits of
endoscopic over microscopic tympanoplasty, with “to verify which method is safer,
comparing the endoscopic technique with the microscopic one” as the primary objective
and with “identify possible advantages and disadvantages of each technique, as well
as possible benefits in choosing these treatments” as the secondary objective.
PICO Strategy Adapted for Systematic Review
Intervention (what will be seen in the review): Raising of a hypothesis of primary
data from studies that assess the benefits of endoscopic versus microscopic tympanoplasty
treatment. Control (already established background, exploratory analysis): The endoscopic
technique offers a less invasive access, as well as better visualization of the middle
ear structures, which led to the hypothesis of safer procedures and better postoperative
periods for patients, when compared with the microscopic technique. Population (group
of articles that will be observed): Primary data articles that show the differences
and benefits of endoscopic tympanoplasty compared with microscopic treatment.
Expected results: A list with plausible hypotheses that justify or explain the superiority
of one treatment over another. Application/Outcome (who will benefit): The entire
scientific community that seeks to better understand the advantages and benefits of
one treatment over another and to assess the main issues that may support possible
future research aimed at better understanding the physiology behind these benefits.
Research Strategy
The authors searched the MEDLINE/PubMed, EMBASE, SciELO, and Lilacs databases for
all available articles reporting comparison between the endoscopic and microscopic
tympanoplasty techniques. The string used for searching the databases was as follows,
considering titles and abstracts: (endoscopic tympanoplasty) AND (microscopic tympanoplasty) AND (outcomes OR benefits OR hearing outcomes).
Eligibility Criteria
All primary data articles were considered eligible studies. Thus, descriptive, cross-sectional,
observational, case-control, cohort, case reports, and controlled clinical trials
have been revised. Studies were included without restriction of language, period,
or location.
All controlled clinical trial studies that contained terms found in their titles or
abstracts by searching the databases using the complete string with optimized keywords
and organized with Boolean operators were selected. Therefore, only primary studies
that evaluated the outcome and comparison between treatment with endoscopic tympanoplasty
and microscopic tympanoplasty were selected.
Exclusion Criteria
Secondary data studies published in the form of letters to the editor, guidelines,
literature reviews, narrative reviews, systematic reviews, meta-analyzes, and abstracts
were excluded.
Studies that did not describe the specificities chosen by the researchers as an objective
for the present research or that were unclear were also excluded. Other exclusion
criteria were: 1) Articles that did not investigate any pathophysiological, symptomatic,
subjective, or objective outcome or result related to treatment with endoscopic or
microscopic tympanoplasty; 2) articles that did not specify in detail in the study
methodology how each investigated favorable results or outcomes were evaluated; 3)
articles in a language other than English that are not fully available in English;
and 4) duplicates.
Data Analysis
The process of analyzing and extracting information from selected and eligible studies
was performed using a specific form for systematic reviews prepared by the authors
in Microsoft Excel software (Microsoft Corporation, Redmond, WA, USA). In this form,
the title and abstract of each selected study were first added. Then, all titles and
abstracts were read by the authors to seek and apply the inclusion and exclusion criteria
for each one. Based on titles or abstracts, the articles were selected for full reading,
and those that met at least one inclusion criteria and no exclusion criteria were
included. In case of disagreement between evaluators, a third evaluator made the decision
on the eligibility of the study in question.
Study Selection
After the studies were searched and listed, the authors evaluated full texts of eligible
articles based on the inclusion and exclusion criteria. The inclusion criteria were
as follows:[1] Article whose main or secondary objective was to identify and/or explore favorable
and/or unfavorable outcomes of treatment by endoscopic tympanoplasty and microscopic
tympanoplasty[2]; and articles whose primary or secondary objective was to compare treatment by endoscopic
tympanoplasty with microscopic tympanoplasty. The following types of publications
were excluded:[1] Articles that did not investigate any pathophysiological, symptomatic, subjective,
or objective outcome related to treatment with endoscopic or microscopic tympanoplasty[2]; articles that did not specify in detail in the study methodology how each investigated
favorable outcome was evaluated;[3] articles in a language other than English that do not have full text available in
English;[4] publications whose original articles were inaccessible (only abstracts were available)
and/or in which incomplete data were provided;[5] duplicates;[6] systematic reviews (since this type of article does not provide primary data).
Collected Data
The authors reviewed all relevant studies and independently extracted data, which
were put in a chart with their characteristics, to qualitatively compile the results.
Any discrepancies were resolved by consensus between the authors. The list of all
included studies and their respective study designs is described in the results.
Clinical Outcome
The clinical outcomes of interest were summarized and systematically analyzed, comparing
studies with similar designs and contrasting divergent results. The clinical outcomes
of interest from each included study were highlighted and discussed. Studies that
did not present results or outcomes referring to at least one analyzed technique were
not included in the sample of the present review.
Results
The first phase of the present systematic review found 99 articles in 4 databases.
After deleting 18 duplicate studies, 81 studies were selected by the reviewers for
reading their titles and abstracts. Of these, 28 articles were excluded according
to the established exclusion criteria and 15 articles were included in the second
step, which consisted of reading the entire manuscript. The entire article selection
process is described in [Fig. 1], which shows the PRISMA flow diagram for the inclusion of articles.
Fig. 1 PRISMA diagram. Source: developed by the authors.
All articles included in the present study were reviewed by the authors and their
results and conclusions were discussed to summarize all the results and support the
discussion on the topic. The highlights of each article and the design of each study
are shown in [Table 1].
Table 1
Endoscopic Tympanoplasty Compared with Microscopic Tympanoplasty: Study Designs and
Conclusions of Included Studies
|
Author and year
|
Study design
|
Conclusions
|
|
1
|
Aoki (2001)[38]
|
Retrospective
|
The endoscopic approach was effective for the treatment of attic cholesteatoma.
|
|
2
|
Ayache et al. (2008)[6]
|
Retrospective
|
Otoendoscopy was essential for remaining lesions of the retrotympanum and epitympanum
after MT approach.
|
|
3
|
Botti et al. (2020)[13]
|
Retrospective
|
No significant differences between ET and MT techniques.
|
|
4
|
Choi et al. (2017)[14]
|
Retrospective
|
The ET technique had shorter operation time and reduced pain level.
|
|
5
|
Cohen et al. (2016)[15]
|
Retrospective
|
TM closure success rates, hearing outcomes and surgical time were similar in both
techniques.
|
|
6
|
Dixon et al. (2020)[39]
|
Retrospective
|
TEES may be an alternative to a postauricular approach for removal of cholesteatoma
limited to the middle ear and/or the attic in children.
|
|
7
|
Dündar et al. (2014)[16]
|
Retrospective
|
ET and MT approach had similar results in terms of visualization of the TM and extra
interventions. The first technique had a shorter surgical time.
|
|
8
|
Dunya et al. (2021)[17]
|
Retrospective
|
The ET approach was an appropriate alternative to MT for difficult-to-repair anterior
perforations.
|
|
9
|
Fina et al. (2016)[18]
|
Retrospective
|
Similar results for ET and MT approach without significant statistical differences.
|
|
10
|
Gulsen et al. (2021)[19]
|
Retrospective
|
The ET had graft success rates and hearing results similar to MT approach.
|
|
11
|
Gülşen et al. (2019)[20]
|
Retrospective
|
ET had inferior complications rates, shorter surgical time than MT and similar graft
success rates in anterior perforations of the TM.
|
|
12
|
Guneri et al. (2020)[21]
|
Retrospective
|
ET and MT had similar results in the reconstruction of the ossicular chain. ET surgery
had a shorter duration.
|
|
13
|
Hargunani et al. (2020)[22]
|
Retrospective
|
There was no statistical difference between ET and MT results.
|
|
14
|
Hashim et al. (2020)[40]
|
Retrospective
|
Endoscopic and microscopic IBCT were associated with good success rates. The endoscopic
approach facilitates visualization, and a better understanding of the middle ear anatomy
and the required surgical steps.
|
|
15
|
Hsu et al. (2018)[23]
|
Retrospective
|
The TEES approach can achieve surgical outcomes and hearing restoration comparable
to those of MES. TEES was associated with shorter surgical and anesthesia time.
|
|
16
|
Huang et al. (2016)[24]
|
Retrospective
|
The ET approach offers superior visualization and shorter operative time than MT,
in addition to equal hearing outcomes and perforation rates.
|
|
17
|
James et al. (2017)[41]
|
Prospective
|
TEES is recommended as providing equivalent likelihood of perforation closure to the
postauricular approach but with less postoperative morbidity.
|
|
18
|
Ji et al. (2020)[42]
|
Retrospective
|
The frequency-specific hearing outcomes of ET and MT tympanoplasty were similar.
|
|
19
|
Karataş et al. (2019)[25]
|
Retrospective
|
EIBCT is safer than the MT approach in pediatric patients with COM and has less postoperative
morbimortality.
|
|
20
|
Kim et al. (2021)[26]
|
Retrospective
|
ET has similar graft success rate, comparable hearing outcomes, and shorter operative
period when compared with MT.
|
|
21
|
Kuo et al. (2017)[27]
|
Retrospective
|
The success rate, audiometry improvement, and complication rate are comparable between
ET and MT. ET had smaller operation wounds and lower medical expenditures.
|
|
22
|
Lee et al. (2019)[43]
|
Retrospective
|
The EIBCT technique and MT had similar success rates and hearing improvement.
|
|
23
|
Lee et al. (2020)[28]
|
Retrospective
|
ET offers similar surgical results compared with the MT technique, and a shorter operative
time and hospital stay after surgery.
|
|
24
|
Li et al. (2019)[29]
|
Retrospective
|
Good outcomes and similar results can be maintained during a transition of a surgeon
to adopting ET and teaching it to residents.
|
|
25
|
Li et al. (2021)[30]
|
Retrospective
|
ET has similar results when compared with MT, and a shorter surgical time. The incidence
of delayed facial palsy was not significantly different between the two approaches.
|
|
26
|
Marchioni et al. (2020)[44]
|
Retrospective
|
Endoscopic type I tympanoplasty can be considered as an alternative technique for
tympanic membrane perforations.
|
|
27
|
Marchioni et al. (2015)[45]
|
Retrospective
|
ET is a conservative and minimally invasive technique that showed a reduction of hospitalization
time with a good postoperative ABG.
|
|
28
|
Min et al. (2018)[31]
|
Retrospective
|
ET has smaller operative time and pain than MT, similar hearing improvement and graft
success.
|
|
29
|
Ohki et al. (2019)[32]
|
Retrospective
|
Under favorable conditions of the middle ear, TEES and PAMES resulted in similar hearing
improvement by tympanoplasty without ossiculoplasty. However, under adverse conditions,
TEES was a more beneficial approach.
|
|
30
|
Pal et al. (2019)[46]
|
Randomized Clinical Trial
|
Hearing improvement and graft success was similar for both the ET and the MT technique.
However, postoperative morbidity and surgery time were smaller in the ET approach.
|
|
31
|
Plodpai (2018)[47]
|
Randomized Clinical Trial
|
EOT provides more favorable anatomical and audiometric outcomes, a superior visibility
of middle ear structures, with fewer complications and less invasiveness than MOT.
|
|
32
|
Sanji et al. (2016)[33]
|
Retrospective
|
ET and MT had similar success rates. However, ET was associated with reduced surgery
time.
|
|
33
|
Shakya et al. (2020)[34]
|
Retrospective
|
Similar results without significant statistical difference. ET is a minimally invasive
technique with a shorter surgery time.
|
|
34
|
Shakya et al. (2021)[35]
|
Prospective
|
The ET offered superior visualization avoiding postauricular incision and canaloplasty.
It offers significantly faster completion of the procedure and provides minimally
invasive surgery.
|
|
35
|
Tseng et al. (2018)[37]
|
Cost-effectiveness study
|
The cost-effectiveness analysis indicates that ET is comparable to MT for treating
COM in Taiwan.
|
|
36
|
Wu et al. (2017)[48]
|
Prospective
|
When compared with MT surgery, ET achieves comparable postoperative hearing outcomes
with less invasiveness and a shorter operation time.
|
|
37
|
Zhang et al. (2021)[36]
|
Retrospective
|
ET is a minimally invasive surgery with similar graft success rate, comparable hearing
improvement, fast recovery, and low cost when compared with MT.
|
|
38
|
Zhang et al. (2020)[49]
|
Prospective
|
Hearing improvement was similar in ET and MT techniques. ET had reduced operation
time and postoperative pain.
|
Abbreviations: ABG, air-bone gap; COM, chronic otitis media; EIBCT, endoscopic inlay
butterfly cartilage tympanoplasties; EOT, endoscopic overlay tympanoplasty; ET, endoscopic
tympanoplasty; IBCT, inlay butterfly cartilage tympanoplasty; MES, microscopic ear
surgery; MOT, microscopic overlay tympanoplasty; MT, microscopic tympanoplasty; PAMES,
postauricular microscopic ear surgery; TEES, transcanal totally endoscopic ear surgery;
TM, Tympanic Membrane.
Source: developed by the authors.
A total of 31 included retrospective studies evaluated and compared the success of
the surgical technique and the effectiveness of the two techniques in the final anatomical
result, graft success, and hearing recovery in patients (air-bone gap), all of which
obtained a similar positive result, with no statistically significant difference between
the endoscopic and the microscopic approach. The duration of surgery was compared
in 21 of these studies,[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
[30]
[31]
[32]
[33]
[34]
[35]
[36] 13 of which reported a shorter surgical time in the endoscopic technique.[14]
[16]
[18]
[19]
[20]
[21]
[22]
[24]
[25]
[26]
[27]
[28]
[29]
[30]
[31]
[33]
[34]
[35]
[36] The postoperative recovery time and level of pain presented by patients were evaluated
by nine retrospective studies, seven of which had a significant difference in favor
of endoscopic tympanoplasty, showing a great improvement in both the pain reported
by the patients and the length of stay in the hospital.
The selection also included four prospective studies that found a shorter surgical
time in endoscopic tympanoplasty. In addition, the postoperative period was better
for the patients in these studies, both in terms of length of stay and referred pain.
Both techniques demonstrated similar results in tympanic membrane closure and graft
success rate. Hearing improvement was significant and equivalent in both groups and
the complication rate did not show any statistically significant difference in the
results. Two randomized clinical trials were also included in the present study, both
evaluating hearing outcomes and obtaining equivalence between the two techniques.
The anatomical closure presented better results in the endoscopic approach, as well
as in the postoperative complications, which were minimized; besides, the endoscopic
approach allows a better visualization of the middle ear structures. Surgery time
was shorter in one of the studies and the postoperative period proved to be much more
advantageous in the endoscopic technique.
Only one study evaluated cost-effectiveness parameters, using a simulated mathematical
model in the Taiwanese healthcare system, and no significant difference was found
between the cost-effectiveness of each technique. However, it is important to point
out that these values may vary depending on the reality of each service, as well as
on the available materials and professionals. Thus, the biggest difference was that
the endoscopic approach, probably because it is less invasive, had a lower cost of
postoperative consultation, while the microscopic approach had a slightly higher cost.
Discussion
None of the 38 studies analyzed showed inferiority between the techniques when they
were compared regarding surgical outcomes, such as the success rates of the grafts
performed or postoperative complications at the surgical site. This indicates an adequate
comparison in the safety and effectiveness of the endoscopic approach in technical
terms in relation to the traditional microscopic approach. Moreover, despite being
more recent and not yet fully incorporated in all hospital services, the endoscopic
approach demonstrates a promising capacity to be included and used in large scale.
However, endoscopy may still be preferentially indicated when addressing regions known
to be difficult for the microscopic technique. Thus, surgeries involving manipulation
of the epitympanum, the retrotympanum, or the attic may have a greater weight in the
choice of endoscopy, aiming at the complete removal of lesions without the permanence
of unseen remnants.
Li et al. also state that endoscopic results are positive and suitable even for surgeons
in transition in relation to techniques, allowing for good safety even during the
learning curve of the physician.[29]
However, it should be noted that, in certain studies, the use of the microscope as
a comparative technique was not isolated. In many cases, despite the convenience of
using both hands and greater knowledge and adaptation to microscopy, the endoscopes
served as an aid for a final review of the surgical site, in order to analyze the
unreachable places for the microscope and to reduce the chances of lingering injuries.
In one of the articles, Cohen et al.[15] even use a didactic classification to adequately specify at what level the endoscope
was used as an aid in microscopic surgery (whether only to enlarge the visualization
or even to aid in curettage), being able, therefore, to standardize its results and
those of subsequent studies, bringing greater clarity to the analyses.
On the other hand, among the 31 articles that evaluated audiometric outcomes, none
found significant differences in hearing recovery between the microscopic and the
endoscopic approach, which prompts a discussion about the importance of immediate
indication of speech and cognitive approaches for patients with complications resulting
from chronic otitis media, cholesteatomas, or other conditions that may compromise
the ossicular chain. Considering especially the most vulnerable groups, which would
be the extremes of age, hearing impairment can lead to important consequences on language,
understanding, and socialization. Thus, the very need for a surgical approach to the
tympanic membrane and the analysis of audiometric results subsequent to the procedure
should trigger the attention of the surgeon to adequately and early advise on the
performance of speech therapy or even the indication of the use of individual sound
amplification hearing aids in more complicated and chronic conditions.
There is a theoretical basis that indicates the possibility of an increase in temperature
in the middle ear due to the use of the flashlight at the tip of the endoscope and
in important proximity to the middle and internal structures of the ear during surgery;
however, none of the studies analyzed in the present study list any outcomes related
to this situation, in addition to demonstrating very similar audiometric outcomes
between the evaluated techniques.
Positive factors related to the endoscopic approach to the tympanic membrane include
its cost-effectiveness or lower cost, in addition to shorter surgical, anesthetic,
and hospital stay, which were found in 13 studies.[36]
[37] In addition, aesthetic and postoperative pain outcomes also favored the choice of
this technique in seven analyses. In the approach of pediatric patients, the safety
in choosing endoscopy was even considered superior, considering the narrowness of
the auditory meatus in children, the possibility of tragal incision, and the wide
field of vision made possible by the endoscopic camera.[25]
In the present systematic review, 31 evaluated articles followed the retrospective
methodology, based on the analysis of past cases. Only two were randomized clinical
trials. Thus, the possibility of biases presents during the selection of patients,
the choice of procedures, and the data analysis itself should be pointed out, since
these are factors that reduce the quality of evidence. More randomized and prospective
studies are needed to more accurately measure complication rates, surgery time, postoperative
pain, and audiometric outcomes. Comparative studies related to myringoplasty surgeries
were not included in the present, since this is an approach with its own characteristics
and which is naturally less invasive.
Although still under study, the endoscopic technique has already shown a very positive
potential to become an alternative both as an aid and as a total approach for tympanoplasties,
especially when it comes to beneficial results for the patient (aesthetic result,
pain, time to hospitalization, and comparable surgical quality). For an adequate choice,
therefore, the surgeon must keep in mind that both the microscopic and the endoscopic
technique have in fact comparable results, postoperative complications, and audiometric
outcomes, and that the endoscopic approach can provide more comfort for the patient
regarding pain and aesthetics. However, the availability of adequate materials in
each service, the costs involved in the technique and hospitalization, in addition
to the experience of the physician and comfort regarding the procedure are essential
points to be considered.
Final Comments
The studies analyzed in the present study demonstrate that the results obtained in
terms of tympanic membrane closure, audiometric results, and complication rates in
tympanoplasties by the endoscopic approach are equivalent to the results obtained
by the conventional microscopic method, in addition to allowing, in many cases, less
surgical time and less postoperative pain for patients.
