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the surgical management of cholesteatoma has still remained a controversial subject even over 100 years after the first successful mastoidectomy . throughout the past decade ,
the controversy of canal - wall - up mastoidectomy ( cwum ) versus canal - wall - down mastoidectomy ( cwdm ) in cholesteatoma was addressed .
there seem to be inherent limitations and advantages in both cwum and cwdm including the ease of disease removal , incidence of recurrence , and the extent of postoperative care .
if possible , intact - canal - wall mastoidectomy ( icwm ) is viewed as superior to cwdm due to its better aesthetic consequences and aural hygiene . the higher rate of residual disease is the drawback of icwm rather than cwdm ( 19 - 47.7% vs 5 - 12% ) , which seemed to be because of the poor visualization of particular areas in middle ear during surgery .
the number of criteria , published in the literature , using for choosing the technique in cholesteatoma surgery is few .
it includes patient factors such as age , anatomic factors such as the degree of cellularity of the mastoid , pathologic factors that depend on the degree of extension of cholesteatoma , functional factors that involve hearing affection , and social factors regarding the accessibility of the patient for the follow - up . according to many otologists ,
canal - wall - down procedures provide better visualization in the most part of middle ear than intact - canal - wall procedures .
the study of hulka and mcelveen ( 1998 ) on 12 cadaveric temporal bones confirmed this idea .
they suggested that cwdm showed significantly superior visualization of the lateral epitympanum , posterior crus of the stapes , and sinus tympani rather than icwm . during the past 40 years
, a number of techniques were suggested for getting better intraoperative visualization of middle ear cavity structures in sergeons by sergeries while keeping the posterior canal wall safe .
most of these techniques were intended to make view of the posterior tympanic cavity better particularly , the sinus tympani .
the techniques included reversing the surgeon orientation , using mirrors to see around bony ridges , and temporarily removing the posterior canal wall .
although these methods enhance the visualization approximately , they all have some limitations and none of them has entirely been accepted . in 1967 ,
mer et al . first depicted the use of fiberoptic endoscopes for observing the middle ear cavity .
however , those early otoendoscopes were short of maneuverability since they were connected to surgical microscope stands .
since then , technological advances have made preparations for handheld scopes that coming higher resolution and smaller diameters . at present ,
rigid otoendoscopes are used for primary cholesteatoma surgery and for second - stage organized investigative surgeries .
it has been proved that the 2.7-mm 30 and 70 otoendoscopes are most practical during the primary surgery .
several reports have been published on endoscopy - aided otologic surgery and its associated lower rate of residual cholesteatoma . for example , yung reported a 9.4% rate of residual cholesteatoma later than icwm aided by 0 and 30 endoscopy . similarly on a second look , badr - el - dine ( 2002 ) discovered that using otoendoscopy for the primary icwm surgery , only 8.6% of his operations displayed residual disease .
( 1993 ) found that the rate of residual cholesteatoma following icwm decreased from 47.7% to 5.5% when they start using adjunctive otoendoscopy .
the rates of residual cholesteatoma using endoscopy - aided icwm are comparable to those of cwdm using microscopy . while it is widely accepted and logical that this trend is due to increased visualization of the endoscopes ,
none of the known studies have quantitatively compared visualization through both the approaches in a randomized , blinded manner . in a study by rehl et al .
( 2012 ) , 30 and 70 otoendoscopy on 10 cadaveric temporal bone showed better visualization on sinus tympani and eustachian tube while there is no significant difference among the lateral epitympanum , posterior stapes crus , and round window niche . in this study
, we tried to compare the quality of visualization in different middle ear structures with otoendoscopy compared with cwdm .
patients with the diagnosis of cholesteatoma signed a written consent form after being explained about the study procedure .
they underwent tympanomastoidectomy ( by retroauricular approach routinely done at our institute ) and then those selected for cwdm were included in the study ( 25 patients11 females and 14 males ) .
after removing the cholesteatoma from the involved areas ( using otomicroscope in routine manner in all middle ear structures to the extent that was possible regarding visualization before lowering the posterior canal wall ) , otoendoscopic examination was done with a 4 mm , 0 endoscope by a neurootologist . in all cases ,
the scutum was removed for better vision to the extent that stapedius muscle could be seen . also the incus was removed after recognizing erosion ( resulting in better vision and freedom to act ) .
all five middle ear structures suspected of occult cholesteatoma were evaluated in terms of having or lacking the pathology ( cholesteatoma ) .
these five anatomic sites were lateral epitympanum , sinus tympani , posterior crus of the stapes , round window niche , and eustachian tube orifice .
then , cwdm was performed and all of the mentioned sites were reevaluated for the diagnosis of occult cholesteatoma .
the accurate diagnosis of pathology using endoscopy in these sites was compared with that of cwdm .
statistical analyses were performed with statistical package for the social sciences ( spss ) version 16 ( spss - inc . ,
results were reported as sensitivity , specificity , positive predictive value ( ppv ) , and negative predictive value ( npv ) .
twenty - five patients ( 11 female and 14 male ) were studied . on average , they had suffered from chronic otitis media for 16 years ( 3 - 40  9.3 ) .
the mean age was 46 years ( range from 13 years to 70 years ) . of these patients , 56% presented with granulation tissue , 24% presented with polyp , 80% presented with an ossicular chain destruction , and 28% with tympanosclerotic plaque .
considering cwdm as a gold standard for detecting occult cholesteatoma during surgery , sensitivity , specificity , ppv , and npv of otoendoscope is presented for each site in table 1 .
sensitivity , specificity , positive predictive value ( ppv ) , negative predictive value ( npv ) , and symmetric measures of otoendoscopy in different sites of middle ear , comparing cwd in lateral epitympanum , the otoendoscope showed 93.8% sensitivity and 77.8% specificity with a symmetric measure of 73% ( p < 0.001 ) , demonstrating that there is no significant difference between two techniques visualization .
all of the negative sites in sinus tympani were also detected as negative by cwdm ( 100% specificity ) . in this area ,
in one case , we diagnosed cholesteatoma in sinus tympani with otoendoscope , but after the removal of canal wall , the observed pathology was tympanosclerotic plaque . the sensitivity , specificity , and symmetric measures were 77.8% , 85.7% , and 63% , respectively .
the specificity for round window niche ( as well as sinus tympani and eustachian tube orifice ) was 100% .
its sensitivity was 75% and its symmetric measure was 81% ( p < 0.001 ) .
in all the patients , otoendoscope detected the involved eustachian tube correctly ( sensitivity and specificity 100% ) with a symmetric measure of 100% .
this study showed that otoendoscopy , compared with cwdm , would provide a good visualization of middle ear structures that are suspected for occult cholesteatoma .
the anatomic sites evaluated in this study were lateral epitympanum , sinus tympani , posterior crus of the stapes , round window niche , and eustachian tube orifice .
these anatomic sites were known as areas with difficult visualization and cholesteatoma removal in icwm .
thus , these areas are high risk for residual or recurrent diseases . in this study , instead of
we hypothesized that in relatively shallow structures of middle ear , maneuvering 0 endoscope would replace lateral vision endoscopes .
we can detect a good degree of visualization in lateral epitympanum and round window niche as cwdm .
( 2003 ) reported that most sites of cholesteatoma remnants were seen in sinus tympani . in this study , we found the symmetric measure of this site desirable ( 92% with p - value less than 0.001 and specificity of 100% ) .
previous studies reported that otoendoscopy provided better visualization of sinus tympani than cwdm , since cwdm did not address the obstruction caused by the overlying facial canal .
the poor symmetric measure for posterior crus of the stapes may be due to conservative manipulation of this anatomic site fearing facial nerve or hearing damage . however , some researchers state that the stapedial tendon will block visualization of the posterior crus .
for this reason , posterior crus of the stapes would be best visualized by placing the endoscope inferiorly in the middle ear and then viewing superiorly , seeing the posterior crus of the stapes under the stapedial tendon .
the sensitivity , specificity , and symmetric measure of eustachian tube orifice are all 100% .
however , generally , in our population the number of involved eustachian tubes was four , and we diagnosed all of them correctly using an otoendoscope .
the little amount of involvement can be due to the fact that this anatomic site is more involved in congenital cholesteatomas than acquired cholesteatomas .
however , the access to eustachian tube can theoretically be affected by the distance between umbo and promontorium .
one of the disadvantages of otoendoscope is fogging the lens of the endoscope , but this can easily be handled by using an antifog solution .
moreover , smearing of blood on the tip of an otoendoscope can significantly obstruct one 's view or hinder interpretation of middle ear anatomy .
( 2012 ) on 10 cadaver temporal bones which has used 30 and 70 otoendoscopes .
it showed that otoendoscopy was significantly better than cwdm for sinus tympani , and there was no significant difference for lateral epitympanum , posterior crus of stapes , and round window niche . in a prospective study comparing cwdm , cwum with or without otoendoscopy , meselaty et al .
( 2003 ) reported that after a period of 12 - 48 months of follow - up , all cholesteatoma residuals were from groups of patients with no otoendoscopy .
( 2010 ) reported a recurrence rate of 67% for cholesteatoma in patients treated with 4.3-mm 0 , 30 , 70 otoendoscopy following 3 months to 2 years .
this is comparable with that of cwdm . despite of these results , saravanappa et al .
( 2003 ) in a survey in uk , showed that only 2 - 10% of surgeons use otoendoscope routinely and 7 - 38% use it occasionally .
it should be emphasized that this method has to be used much more in the future by more surgeons , reducing cwdm in selected patients .
the results of the present study confirmed that otoendoscope could be applied in the surgical management of middle ear cholesteatoma .
in fact , the otoendoscopy offers a less invasive procedure with a comparable detecting power of cholesteatoma in anatomic structure that could be hidden in otomicroscopy .
hra contributed in the conception of the work , conducting the study , interpretation of data and revising the draft and approval of the final version of the manuscript .
fa contributed in the conception of the work , responsible for the first draft of the manuscript , acquisition , analysis , interpretation of the data and approval of the final version of the manuscript .
mr cotributed in the conception of the work revising the draft and agreed for all aspects of the work .
nb cotributed in the conception of the work revising the draft and agreed for all aspects of the work .
background : the surgical management of cholesteatoma is a controversial issue , particularly regarding intact - canal - wall mastoidectomy ( icwm ) versus canal - wall - down mastoidectomy ( cwdm ) . the current experiment compared the quality of visualization in different middle ear structures using icwm with otoendoscopy with findings of cwdm by microscopy.materials and methods : the patients diagnosed with cholesteatoma underwent tympanomastoidectomy , and then the patients selected for cwdm were included in the study ( 25 patients : 11 females and 14 males ) . after removing the cholesteatoma from the involved areas , otoendoscopic examination was done with a 4 mm , 0 endoscope by a neurootologist . 
 all five middle ear structures ( lateral epitympanum , sinus tympani , posterior crus of the stapes , round window niche , and eustachian tube orifice ) suspected of occult cholesteatoma were evaluated in terms of having or lacking the pathology . 
 then , cwdm was performed and all of the mentioned sites were reevaluated for diagnosing occult cholesteatoma.results:the symmetric measures were 73% , 92% , 63% , 81% , and 100% for lateral epitympanum , sinus tympani , posterior crus of the stapes , round window niche , and eustachian tube orifice , respectively.conclusion:otoendoscopy was confirmed to have a great potential to be adopted by surgeons as a less invasive procedure in the surgical management of middle ear cholesteatoma .