www.bjorl.org
Brazilian
Journal
of
OTORHINOLARYNGOLOGY
ORIGINAL
ARTICLE
Learning
curve
for
endoscopic
evaluation
of
vocal
folds
lesions
with
narrow
band
imaging
夽
Michał ˙
Zurek
a,
Anna
Rzepakowska
b,∗,
Ewa
Osuch-Wójcikiewicz
b,
Kazimierz
Niemczyk
baMedicalUniversityofWarsaw,StudentsScientificResearchGroupbyOtolaryngologyDepartment,Warszawa,Poland bMedicalUniversityofWarsaw,OtolaryngologyDepartment,Warszawa,Poland
Received15April2018;accepted10July2018 Availableonline4August2018
KEYWORDS Learningcurve; Narrowbandimaging; Vocalfold;
Dysplasia; Glotticcancer
Abstract
Introduction:Theendoscopicmethodsareprogressingandbecomingmorecommoninroutine clinicaldiagnosisinthefieldofotorhinolaryngology.Relativelylargeamountofresearcheshave provedhighaccuracyofnarrowbandimagingendoscopyindifferentiatingbenignandmalignant lesionswithinvocalfolds.However,littleisknownaboutlearningcurveinnarrowbandimaging evaluationoflaryngeallesions.
Objective: Theaim ofthisstudy was todeterminethe learningcurve for thenarrow band imagingevaluationofvocalfoldspathologiesdependingonthedurationoftheprocedure.
Methods:Records of134narrowbandimagingthatwere analyzed intermsoftheduration oftheprocedureandtheaccuracyofdiagnosisconfirmedbyhistopathologicaldiagnosiswere enrolledinthestudy.Thenarrowbandimagingexaminationswereperformedsequentiallyby oneinvestigatoroveraperiodof18months.
Results:Theaveragedurationofnarrowbandimagingrecordingswas127.82s.All134 stud-iesweredividedinto subsequentseriesofseveralelements.Anevidentdecreaseintimeof investigationwasnoticedbetween13thand14thseries,whentheexaminationsweredivided into 5elements series, which correspondsto thedifference between 65thand 70th subse-quent narrowband imagingexamination. Parallelgroups of67 examinations were created.
夽 Pleasecitethisarticleas: ˙ZurekM,RzepakowskaA,Osuch-WójcikiewiczE,NiemczykK.Learningcurveforendoscopicevaluationof
vocalfoldslesionswithnarrowbandimaging.BrazJOtorhinolaryngol.2019;85:753---9.
∗Correspondingauthor.
E-mail:arzepakowska@wum.edu.pl(A.Rzepakowska).
PeerReviewundertheresponsibilityofAssociac¸ãoBrasileiradeOtorrinolaringologiaeCirurgiaCérvico-Facial.
https://doi.org/10.1016/j.bjorl.2018.07.003
1808-8694/©2018Associac¸˜aoBrasileiradeOtorrinolaringologiaeCirurgiaC´ervico-Facial.PublishedbyElsevierEditoraLtda.Thisisanopen accessarticleundertheCCBYlicense(http://creativecommons.org/licenses/by/4.0/).
754 ZurekMetal. Group1included1stto67thsubsequentnarrowbandimagingexamination;Group2---68thto 134thnarrowbandimagingexaminations.Thenon-parametricUMann---Whitneytestconfirmed statisticallysignificantdifferencebetweenthemeandurationofnarrowbandimaging exam-inationinbothgroups160.5sand95.1s,respectively(p<10−7).Sensitivityandspecificityof narrowbandimagingexaminationinthefirstgroupwererespectively:83.7%and76.7%.Inthe secondgroup,theseindicatorsamounted98.1%and80%respectively.
Conclusions:Aminimumof65th---70thnarrowbandimagingexaminationsarerequiredtoreach aplateauphaseofthelearningprocessinassessmentofglottislesions.Analysisoflearning curves is useful for the development oftraining programsand determination ofamastery level.
© 2018 Associac¸˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Published by Elsevier Editora Ltda. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/). PALAVRAS-CHAVE Curvade aprendizado; Imagensdebanda estreita; Pregavocal; Displasia; Câncerglótico
Curvadeaprendizadoparaavaliac¸ãoendoscópicadelesõesdepregasvocaiscom imagemdebandaestreita
Resumo
Introduc¸ão: Os métodos endoscópicosestão progredindoese tornando comunsno
diagnós-tico clínico de rotina também na otorrinolaringologia. Um número relativamente grande
de pesquisas demonstrou alta precisão na endoscopia com imagem de banda estreita na
diferenciac¸ãodelesõesbenignasemalignasnaspregasvocais.Entretanto,poucosesabesobre acurvadeaprendizadonaavaliac¸ãodadebandaestreitadelesõeslaríngeas.
Objetivo:Determinaracurvadeaprendizadoparaaavaliac¸ãoporimagemdebandaestreita dasafecc¸õesdaspregasvocais,deacordocomadurac¸ãodoprocedimento.
Método: Foramincluídosnoestudo134registrosdeimagensdebandaestreitaanalisadasem termosdadurac¸ãodoprocedimentoedaacuráciadodiagnósticoconfirmadopelodiagnóstico histopatológico.Osexamescomimagemdebandaestreitaforamfeitossequencialmentepor uminvestigadorpor18meses.
Resultados: Adurac¸ãomédiadosregistrosdeimagemdebandaestreitafoide127,82s.Todos os 134estudos foramdivididos em sériessubsequentes devários elementos.Uma evidente diminuic¸ãonotempodeinvestigac¸ãofoiobservadaentreasséries13e14,quandoosexames foramdivididosemsériesdecincoelementos,oquecorrespondeàdiferenc¸aentreo65◦ e 70◦ examesdeimagem debanda estreita subsequentes.Foramcriadosgrupos paralelosde 67exames.Ogrupo1incluiuo1◦ ao67◦ examedeimagemdebandaestreitasubsequente; Grupo2---o68◦ ao134◦ examedeimagemdebandaestreita.Otestenão-paramétricoUde Mann-Whitneyconfirmouumadiferenc¸aestatisticamentesignificanteentreadurac¸ãomédiado examedeimagemdebandaestreitaemambososgruposde160,5se95,1s,respectivamente (p<10-7).Asensibilidadeeespecificidadedoexamedeimagemdebandaestreitanoprimeiro grupoforam,respectivamente:83,7%e76,7%.Nosegundogrupo,essesindicadoresforam98,1% e80%,respectivamente.
Conclusões:Ummínimode 65a70examesdeimagemdebanda estreitaénecessário para seatingirafasedeestabilizac¸ão(plateau)doprocessodeaprendizadonaavaliac¸ãodelesões deglote.Aanálisedascurvasdeaprendizadoéútilparaodesenvolvimentodeprogramasde treinamentoedeterminaron.
© 2018 Associac¸˜ao Brasileira de Otorrinolaringologia e Cirurgia C´ervico-Facial. Publicado por Elsevier Editora Ltda. Este ´e um artigo Open Access sob uma licenc¸a CC BY (http:// creativecommons.org/licenses/by/4.0/).
Introduction
Inmedicine,asinmanyotherfieldsofnaturalsciences,the effectivenessofspecificproceduresisofgreatimportance.
Throughout the world there are different regulations
concerning competency in performance of specific
meth-ods. For example in the United States the competency
in emergency ultrasonography requires performing of
150---300 procedures.1 The endoscopic methods are
pro-gressinginmanymedicalfieldsandbecomingmorecommon
in routine clinical diagnosis also in otorhinolaryngology; for nasal cavity, nasopharynx and larynx assessment. The questionaboutmethod’sreliabilityismostimportant. How-ever,ifthecredibilityisproven,theaspectofinvestigator’s experiencemayinfluenceeffectivenessofthemethod.The learning curvesare usuallyused for determination of the
number of procedures for physicians to obtain the right qualifications.Thosecurvesaremathematicalandgraphical presentationofthe relationshipbetweentheeffortputin andtheresults obtainedfromthelearning.2---5 The typical
learningcurveisshowninFig.1.Therelationshipbetween efficiency (vertical axis) and experience (horizontal axis)
is not a linear dependence. It takes a sigmoidal shape,
which means that the learning speed changes depending
ontheleveloftheexaminedperson,e.g.physician.2,5The
beginning of the curve is different from zero, becauseit isassumed thateachlearner startswithacertainamount ofknowledge (atleasttheoretical).Thisbasic levelis the referencepoint,towhichfurtherefficienciesarereferred.
Initially the examined person gets acquainted with the
procedure,whatreflectsthefirststageof‘‘slowprogress’’.
Then, with each repetition the efficiency of the process
increases,assomeaspectsoftheprocedureareimproved. This isnextstage ofsignificant increase ofefficiencyin a relativelyshorttimeiscalled‘‘steepprogress’’phase.The efficiencyincreaseslowsdowneventually,reachingthelast ‘‘plateau’’phase.2
The ‘‘experience’’ and ‘‘efficiency’’ on the learning
curve(Fig.1)arequalityvariablesandthusunmeasurable directly.Itisimpossibletomarktheirvalueonthenumerical axis, therefore other, directly correlating andmeasurable variablesshouldbeused.
The experience is usually measured by the number of
performedmedicalprocedures,forexampleendoscopies.6,7
The amount of tests assumes a total positive values and
can be presented on the horizontal axis of the chart for the learning curve. Otherwise, the measure of effective-nessmaycorrelatetodifferentvariables.Radiologistsuse thenumberof correctdiagnoses duringtheassessmentof a series of images.8 Surgeons evaluate the postoperative
complications.6,9An interestingmeasureistheassessment
ofthequalityofspecificprocedurebasedonquestionnaires that patients fillat determined stages of the therapy.An exampleistheOswetryquestionnaire.9
Narrowbandimaging(NBI)isamodernendoscopy intro-ducedinlaryngologyin2006.Themethodusesspecialfilters to obtain two wavelengths of light --- green (540nm) and
E F F I C I E N C Y
Asymptote: maximal performance
Plateau
Steep progress
Initial level of slow progress
EXPERIENCE
Figure1 Ageneraloutlineofthelearningcurvepresenting themainpropertiesofthecurve.
blue(415nm),thatareselectivelyabsorbedbyhemoglobin inbloodvesselsofthemucosa.10---14
Relatively large amount of researches proved high
accuracy of NBI endoscopy in differentiating benign and
malignantlesionswithinvocal folds.10---14 Theprocedure is
performed in office setting with topical anesthesia with
lidocainegel tothe nasal cavity and if necessary topical lidocainesprayontheposteriorpharyngealwall.According totheclassificationproposedbyNietal.from2011,there aredescribedfivevascularpatternsonthelaryngealmucosa (typeVconsistsof3subtypes).10TypesfromItoIVare
char-acteristicforbenignlesions,whilesubtypesVa-Vcindicate malignantchanges.
Many factors may affect the effectiveness of vascular patternassessmentwithNBIendoscopyofthevocalfolds. Forthecorrectevaluationofthemucosalvesselsitis
nec-essarytomaximallyapproximatetheimageofthemucous
membrane.Thisrequiresfromtheinvestigatorskillful
han-dling with the endoscope, high precision of movements
andexperience withimage recognition.The other aspect
is patients’ history andprevious therapies that may have
an impact on the appearance of vocal folds mucosa (for
example radiotherapy, chemotherapy, previous laryngeal
microsurgeries).Additionally,somepatientshaveexcessive gaggingandrequiretopicalanesthesiawithlidocainespray thatisnotalwayseffectiveincontrollingthereflex.
Therearenoavailablestudiesconcerningtheassessment oflearningcurvefor NBIendoscopyinevaluationof vocal foldlesions.
Theaimofourstudywastodeterminethelearningcurve fortheNBIevaluationofVFpathologiesdepending onthe durationoftheprocedureforoneinvestigator.
Methods
ThestudywasapprovedbytheResearchEthicsCommittee
of the local Medical University (KB/56/2015). All partici-pantsgavetheirinformedconsent.
TheresearchmaterialswererecordingsoftheNBI exami-nationscarriedoutsequentiallybyoneotolaryngologistover theperiodof18monthsinpatientswithsuspiciouslesions limited to VF that on initial diagnosis were described as hypertrophy,ulceration,leukoplakia,tumorandwhowere forthisreasonplannedformicrosurgeryofthelarynx.We excludedfromtheanalysisthefollow-upNBIexaminations. Theinvestigator,ENTspecialist,startedthepractical expe-riencewithNBIendoscopywiththefirstincludedrecordings. Previouslythedoctorhadparticipatedinoneinstructional course and prepared theoretically. Moreover, the investi-gatorhad been previously familiar withother endoscopic procedures on larynx, especially laryngovideostroboscopy and wasperforming excisional biopsy or laryngeal
micro-surgery for a large part of evaluated patients with the
feedbackonthehistopathologicalresults.
Weenrolledtothestudy134recordingsofNBIthatwere analyzedintermsofthedurationoftheprocedureandthe accuracyof diagnosis.The NBIwasperformed withVisera
Elite OTV-S190 video system and ENF-VH videoendoscope
byOlympusMedicalSystems(Volketswil,Switzerland).The patientduringtheexaminationwasinthesittingposition. Theflexibleendoscopewasinsertedthroughthenostrilafter
756 ZurekMetal. topical anesthesia with lidocaine gel. If the patient
pre-sentedgagging,twoorthreedosesoflidocainespraywere appliedonposteriorpharyngealwall.Theevaluationof
vas-cularpatternwasperformed aftermaximalapproximation
and magnification of the lesion. If only normal
longitudi-nal vessels were visualized, the Type I was recognized.
The longitudinal, but enlargedin diameter andbranching vesselswere indicative of TypeII. Ifthe whiteplaque of hyperkeratoticepitheliumwascoveringtheblood vessels, TypeIIIwasinitial diagnosis, butonly ifthe vascular pat-tern ofmucosa surroundingthe leukoplakiahad TypeI or TypeII.Ifbrownish,regulardotsoflowdensitywere visual-izedwithinthelesionorinthesurroundingofleukoplakia, theyindicatedTypeIV.Theirregular,spiralorwormshape,
brownish vessels were identified as Type Va. The same
image,butwithhigherdensityofirregularvesselswitheven moredisturbedshapesindicatedTypeVb.Theabrupt disap-pearanceofdistortedvesselsindicatedTypeVc.Thelesions withTypeItoIVwereidentifiedbytheinvestigatorasbenign withNBIexamination.ThosewithTypeVwerediagnosedas malignantlesions.Eachpatienthadtheexcisionalbiopsyof theVF lesionduring laryngeal microsurgery thatwas
per-formed within 0---3 days post NBI examination. The final
diagnosiswasconfirmedbyhistopathologicalexamination. Statisticalanalysiswasperformedusing:MicrosoftExcel 2016andStatistica13.1.Intheanalysiscontrolcharts:X-bar andRangechartswereused.TheShapiro---Wilktestwasused toconfirmthenormaldistributionofdata.Theintergroup analysiswasbasedonnon-parametricUMann---Whitneytest. Valuedifferences of p<0.05 were considered statistically significant.Toconfirmthecorrectnessofanalysissensitivity andspecificityofNBIexaminationswerecomputed.
Results
Thestudyenrolled134NBIrecordingsofglottislesions, per-formedsequentiallybyoneinvestigatorovertheperiodof
18months.The age of patientswhose examinationswere
includedintotheanalysisrangedbetween23and89years. Theaverageagewas60.7years.Menrepresentedthe major-ity of patients 89 (66.42%). The average duration of all NBI recordings was127.82s (about 2min and 9s). Basing
on vascular patterns evaluated with NBI, there were 93
benign lesions (Types I---IV according to Ni classification) and 41 malignant lesions (Type V). The histopathological examinationsconfirmedbenigncharacterin88changesand malignantin46.Table1presentsthedemographicdataof
the study group and results of Narrow BandImaging and
histopathologicaldiagnosesinanalyzed material. Compar-ingtheNBIandhistopathologicalresults,therewasobtained sensitivityandspecificityof92.13%and77.78%,respectively forallNBIexaminations.
The establishment of the learning curve for the NBI
examination was started by comparing the durations of
nextexaminationsanddeterminingthedependenceofthe
durationin sequence of examinations (Fig.2). The graph
presenting the duration of subsequent NBI examinations
is characterized by a downward trend that suggests the
correctnessoftheoriginalassumptionthattheexamination timeisshorteningwiththeexperienceoftheinvestigator.
Table 1 The demographic data of the study group and resultsofNarrowBandImagingandhistopathological diag-nosesinanalyzedmaterial.
Characteristics Value
NumberofNBIexaminations 134
Meanageofpatients 60.7years
Female 45(33.6%)
Male 89(66.4%)
MeantimeofNBIexaminations;SD (s);Median(s)
127.82s;5.19s;110s
NBIvascularpatterndiagnosedin134lesions
TypeI 16 TypeII 36 TypeIII 35 TypeIV 6 TypeVa 10 TypeVb 15 TypeVc 16
Histopathologicaldiagnosisofanalyzedlesions
Normalmucosa 4
Inflammatorychanges 42
Parakeratosis/hyperkeratosis 36
Lowgradedysplasia 6
Highgradedysplasia 10
Preinvasivecancer 9
Invasivecancer 27
Inordertocheckbetweenwhichexaminationsoccurred significantlydifferentinthedurationofperformance, con-trol charts were used. All 134 studies were divided into subsequentseriesofseveralelements.Theevidentdecrease intimeofinvestigationwasnoticedbetween13thand14th series,whentheexaminationsweredividedinto5elements series,which correspondstothe differencebetween 65th and70thsubsequentNBIexamination(Fig.3).
BasingonX-barchartresults,all134studiesweredivided intotwogroups, witha line of divisionbetween the65th and 70thresearch.There werecreated parallel groups of 67examinations.Group1included 1stto67thsubsequent
NBI examination; Group 2 --- 68th to 134th NBI
examina-tions. Table 2 presents the comparison of demographic
data, mean timeof NBI examination, results of NBI eval-uationandhistopathologicaldiagnosisbetweenGroup1and Group2.
The differences of mean duration of NBI
examina-tion between groups were also presented in the form
of histograms and on the box-and-whisker diagrams
(Figs.4and5).TheNBIexaminationswerealsoevaluated
in terms of the data distribution. The Shapiro---Wilk test confirmedthatthefirstgrouphadnormaldistribution.The secondgroupdidnotshowanyofthecommonlyknown dis-tributions.Therefore,theintergroupanalysiswasbasedon non-parametrictests.Thenon-parametricUMann---Whitney test confirmed statistically significant difference between mean durationof NBIexaminationsin both groups 160.5s and95.1s,respectively(p<10−7).
Wecheckedalsothe accuracy of NBIduringthe learn-ingprocesscomparingtheevaluatedvascularpatternswith
300 250 200 150 100 50 0 0 20 40 60 80 100 120 140 160 Case number Dur ation in sec
Duration of NBI exam
Figure2 AgraphspresentingthedurationinsecondsofsubsequentNBIexaminations.
Histogram of means Histogram of means 220 200 180 160 140 120 100 80 60 40 20 0 1 2 3 4 5 6 7 8
X-bar and R charts
X-mean: 127,82 (127,82); Sigma: 49,079 (49,079); n: 4,963 201,44 127,82 54,203 5 10 15 20 25 Range: 113,67 (113,67); Sigma: 42,437 (42,437); n: 4,963 230,58 101,04 0,0000 25 20 15 10 5 300 250 200 150 100 50 0 -50 0 2 4 6 8 10 1 3 5 7 9 11
Figure3 X-barandrangechartsanalysisofNBIexaminationsdividedintosubgroupsof5elements(26groupsconsistsof5NBI examinations,last27thgroupconsistof4examinations).
Table2 Thecomparisonofdemographicdata,meantimeofNBIexamination,resultsofNBIevaluationandhistopathological diagnosisbetweenGroup1---1stto67thsubsequentNBIexaminationandGroup2---68thto134thNBIexamination.
Characteristics Group1 Group2
NumberofNBIexaminations 67 67
Meanageofpatients 60.75 60.61
Female 16 29
Male 51 38
MeandurationofNBIexaminationinseconds;SD;Median 160.5s;59.6s;155s 95.1s;39.4s;88s
NBIdiagnosisoflesions
Benign(TypeI---IV) 38 54
Malignant(TypeV) 29 13
Histopathologicaldiagnosis
Benign(normalmucosa,inflammatorychanges,parakeratosis,lowgradedysplasia) 37 52
758 ZurekMetal. 20 18 16 14 12 10 8 6 4 2 0 0 40 80 120 160 200 240 280 320 20 60 100 140 180 220 260 300 0 40 80 120 160 200 240 280 320 20 60 100 140 180 220 260 300 Number of cases Group 1 Group 2 Categorized histogram
Duration (in sec) Duration (in sec)
Figure4 ThehistogramofthedistributionofthedurationofsubsequentNBIexaminationsinbothanalyzedgroups.(Group1 ---1stto67thsubsequentNBIexamination,Group2---68thto134thNBIexamination).
Box plot 180 160 140 120 100 80 1 2 Group Dur
ation (in sec)
Mean Mean+/-SE Mean+/-1,96*SE
Figure5 Thebox-and-whiskerdiagramofmeandurationof NBIexaminationsbetweenanalyzedgroups.(Group1---1stto 67thsubsequentNBIexamination,Group2---68thto134thNBI examination).
histopathologyresultsforbothgroups.Sensitivityand speci-ficityofNBIexaminationinthefirstgroupwererespectively: 83.7% and 76.7%. In the second group, these indicators amounted98.1%and80%respectively.
Discussion
Modern diagnostic techniques are designed to increase theefficiency andprecision of clinical diagnosis. The NBI endoscopyisoneofthemodernmethodsforaccurate eval-uation and differentiation between benign and malignant lesionswithinaerodigestivetrack.However,performingand evaluatingtheNBIdependsontheinvestigatorexperience. Many publications confirm accuracy of NBI in predicting
thefinalhistopathologywithinVFlesions.However,littleis knownabout learningcurvein NBIevaluationoflaryngeal lesions.
Thisstudy aimedatdefining thelearningcurvefor NBI assessmentofVFslesionsandindicatingtheminimum num-ber of examinationsnecessary for precise and competent diagnosis.Ouranalysisconfirmedthatafter65th---70thNBI examination theinvestigator can reachtheplateauphase ofthelearningprocess.Theinformationaboutlearning pro-cess and evaluation of experience acquisition in specific methodisusefulforassessmentofskills,developing train-ingprogramsanddeterminingtheconditionsfor receiving certificates.
Thelimitationofpresentedstudyistheaspectthat anal-ysis of the learningprocess concernsa single investigator results. For accuratedetermination of the exact learning curve oftheNBI inevaluation ofvocal foldslesionsthere arerequired additionalanalysisinvolving a largernumber of doctorsat variousstages of the specializationpractice andalsotakingintoaccountthetypeofpracticeperformed (outpatient or surgical). The another aspect that can be included into theanalysis is, for example,feedback from patientsaftertheexamination,expressedintheformofa scoredquestionnaire.
As mentioned in the introduction, learning curves have alreadybeen defined for many medicalprocedures. Trincadoetal.presentedtheeffectivenessoflaparoscopic proceduresinanaldiseases.Theyanalyzedvariousfactors (complications, conversion rate, mortality, number of involvedlymphnodes)forestimationofthelearningcurve ofthisprocedureandfoundtheplateauphaseforthe70th performed laparoscopy.6 Oda et al. introduced a special
training program on endoscopic submucosal dissection of
early gastric cancer, in which they managed to assess a
learning curve for the procedure with a plateau phase
The evaluation of learning in NBI procedure is quite popularingastroenterology,butnotinotorhinolaryngology. ThelearningcurveforNBIinthediagnosisofprecancerous gastric lesionsby usingWeb-based videoswasdetermined byDias-Silva etal.7The satisfactoryaccuracy levelin the
recognition of themucosal vascular patternwas obtained aftertheevaluationof150NBIexamination.7McGilletal.
evaluatedthelearningcurveforNBIdiagnosisofcolorectal
polyps performed by five endoscopists and they assumed
as the target point Negative Predictive Value (NPV) at
the level of 90% or higher and concordance between NBI
and histology at the level of 90% or higher.16 Xiu et al.
in their study confirmed that magnifying NBI could be
learnt easily and rapidly by beginning endoscopists for
diagnosis of oesophageal neoplastic lesions and that the less-experiencedendoscopistscouldbenefitfromthe
train-ingprogramme,thatwasproposedbyauthorsandimprove
their diagnostic skills to the level of highly experienced endoscopists.17 Patel etal. analyzed learning possibilities
for colorectal polyps assessment with NBI endoscopy by
gastroenterology trainees and found that a median of 49
videos wasrequired toachieve competency with the90%
agreement of NBI with histopathology.18 Baldaque-Silva
et al. analyzed endoscopic assessment and grading of
Barrett’sesophagus usingmagnified NBI and found within
thelearningprocessadecreaseinthetimeneededfor eval-uationandan increaseinthecertaintyofprediction,with thesensitivityfor detectionof neoplasiarangingbetween 62%and90%,irrespectiveofinvestigators’expertise.19
Conclusion
Minimum of 65th---70th NBI examinations are required to
reach plateauphase of learning process in assessment of glottislesions.Analysisoflearningcurvesisusefulfor devel-opingtrainingprogramsanddeterminationofmasterylevel.
Ethical
approval
This article does not contain any studies with animals
performed by any of the authors. All procedures
per-formed in studies involving human participants were
in accordance with the ethical standards of the
insti-tutional and/or national research committee and with
the 1964 Helsinki declaration and its later amendments
or comparable ethical standards. Informed consent was
obtained from all individual participants included in the study.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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