Otology Korean J Otorhinolaryngol-Head Neck Surg 2017;60(10):491-6 / pissn 2092-5859 / eissn 2092-6529 https://doi.org/10.3342/kjorl-hns.2017.00087 Management of Attic Cholesteatoma While Preserving Intact Ossicular Chain; Modified Bondy Technique vs. Canal Wall Up Mastoidectomy with Tympanoplasty Type I & Scutumplasty Dan Bi Shin, Jung On Lee, Tae-Uk Cheon, Jung Gwon Nam, Tae-Hoon Lee, and Joong Keun Kwon Department of Otolaryngology-Head and Neck Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea 상고실진주종에대한수술적치료로귓속뼈연쇄를보존하는방법비교 ; 변형 Bondy 술식 과 폐쇄공동술식 / 제 1 형고실성형술및순판성형술 신단비 이정온 천태욱 남정권 이태훈 권중근 울산대학교의과대학울산대학교병원이비인후과학교실 Received February 3, 2017 Revised May 29, 2017 Accepted June 4, 2017 Address for correspondence Joong Keun Kwon, MD, PhD Department of Otolaryngology- Head and Neck Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, 877 Bangeojinsunhwando-ro, Dong-gu, Ulsan 44033, Korea Tel +82-52-250-7180 Fax +82-52-234-7182 E-mail kwonjk@live.co.kr Background and ObjectivesZZThe aim of this study is to evaluate the clinical outcomes of two surgical techniques-modified Bondy technique and canal wall up mastoidectomy with tympanoplasty type I and scutumplasty (CWUM/T1)-to remove attic cholesteatoma while preserving ossicular chain intact. Subjects and MethodZZA retrospective study was performed on 23 surgical cases for the attic cholesteatoma with postoperative audiometry data of more than six months after surgery. The patients postoperative clinical features and audiometric results were compared between the two surgical groups. ResultsZZOut of 23 patients, CWUM/T1 was performed in 13 cases and modified Bondy technique was used in 10 cases. There were no significant differences for the preoperative and postoperative audiograms between the two groups. But air-bone gap increased significantly after CWUM/T1 while it decreased after modified Bondy technique. Three cases with postoperative problems were seen after CWUM/T1 (recurrent cholesteatoma, pars tensa adhesion, recurrent otitis media with effusion). Two cases with postoperative problems were found after modified Bondy technique (mild attic retraction, pars tensa retraction). ConclusionZZBoth surgical techniques seem to be adequate to treat attic cholesteatoma while preserving intact ossicular chain. Given good postoperative hearing results and stability of open cavity against recidivism, the modified Bondy technique seems to be a good choice for the attic cholesteatoma with intact ossicular chain when mastoid is not highly pneumatized. Korean J Otorhinolaryngol-Head Neck Surg 2017;60(10):491-6 Key WordsZZ Audiometry ㆍ Cholesteatoma ㆍ Mastoid ㆍ Otologic surgical procedures. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright 2017 Korean Society of Otorhinolaryngology-Head and Neck Surgery 491
Korean J Otorhinolaryngol-Head Neck Surg 2017;60(10):491-6 서론 진주종성중이염의수술에서폐쇄공동술식이냐개방공동술식이냐하는선택의문제는늘논란이있어왔다. 폐쇄공동술식은개방공동술식에비해수술후청력이양호하나 1,2) 재발가능성이상대적으로높다고알려져왔고, 3,4) 개방공동술식은수술시간및창상치유기간이상대적으로길지만재발위험이적다. 5-7) Bondy는만성중이염수술에서고막과귓속뼈를보존하는변형근치유돌절제술 (Bondy operation) 을소개하였으나높은안면능선 (facial ridge) 과정맥동경막각 (sinodural angle), 유돌첨 (mastoid tip) 에서유돌벌집 (mastoid air cell) 이남기쉬운술식의결점때문에폭넓게선택되지못했다. 이러한단점을극복하기위해 Sanna 등은변형Bondy 술식 (modified Bondy technique) 을도입하였으며상고실진주종환자의청력이좋거나정상일경우혹은유일청 (only hearing) 이거나건청 (better hearing) 일때주로사용하여왔다. 8,9) 국내에서는변형Bondy 술식에대한치료성적이보고된적이있으나, 10) 폐쇄공동술식 / 제1형고실성형술및순판성형술 (canal wall up mastoidectomy with tympanoplasty type I and scutumplasty, CWUM/T) 의치료성적과비교된것은없다. 저자들의경험상귓속뼈연쇄가정상인상고실진주종에서 CWUM/T1을선택한경우유양돌기함기화가상대적으로좋았음에도불구하고수술후기도청력이나빠진경우가간혹있었던반면, 변형Bondy 술식이후에는수술전기도청력이대부분잘유지되었다. 이에저자들은귓속뼈연쇄가정상인상고실진주종환자들을대상으로변형Bondy술식과 CWUM/T1의치료성적을청력결과와함께비교해보고자하였다. 대상및방법 2001년 8월부터 2015년 12월까지단일병원에서정상적인귓속뼈연쇄를보존한채수술을시행한진주종환자 40명의의무기록을검토하였다. 포함기준은 1) 상고실진주종, 2) 수술전과수술 6개월이후까지청력검사및고막모습을확인할수있었던증례로한정하였으며, 조건을충족한 CWUM/ T1 13 예, 변형 Bondy 술식 10 예의자료를후향적으로분석하 였다. 본연구는기관임상윤리심의위원회 (IRB No. UUH 2017-01-016) 를통해승인되었다. 두군의평균연령과남녀비는비슷하였고수술후추적 관찰기간은 CWUM/T1 이더길었다 (Table 1). 수술방법 진주종에의한상고실파괴가광범위하지않으면서유양돌 기함기화가큰경우 CWUM/T1 및순판성형술 (scutumplasty) 을주로시행하였고, 상고실파괴정도가크거나유양 돌기의함기화가적은경우변형 Bondy 술식을우선적으로선 택하였다. 폐쇄형유돌절제술 / 제 1 형고실성형술및순판성형술 (CWUM/T1) 후이개접근법을통해폐쇄형유돌절제술을시행하고유돌 동 (antrum) 후방과외이도를통해진주종의범위를확인하 고제거하였다. 순판의골결손부재건은전체두께의이갑개 연골 (conchal cartilage) 을순판결손크기보다크게재단하 여외이도내측면에서덧대고연골막이나근막으로덮어주었 다. 필요시재건에사용된연골판크기에맞게순판전방과 후방에 1 mm diamond burr 로새로운뼈고랑 (bony furrow) 을만들어재건된연골판이안정적으로위치하게하였다. 변형 Bondy 술식 후이개절개로접근하여고막을고실륜 (tympanic annulus) 후방과망치뼈에서분리하였으며고막배꼽 (umbo) 은망치뼈 에붙여둔채고막을앞으로젖혔다. 고실내에서진주종의범 위와귓속뼈연쇄상태를확인한뒤유돌절제술과상고실개 방술을시행하였다. 상고실개방술중모루뼈짧은다리 (incus short process) 와모루뼈몸통 (incus body) 바로외측의뼈다리 (bony bridge) 는 3-mm diamond burr 를이용하여계란껍질 처럼얇게갈아내고귓속뼈가손상되지않게 pick 등으로조심 스럽게제거하였다. 모루뼈하방에서는고실륜높이까지안 면능선을낮추어개방공동을만들고뼈외이도후하방은뼈 고실륜이노출될때까지천공기 (drill) 로넓혀고막전체가외 이도를통해노출되도록하였다. 수술후발생할수있는상고 Table 1. Demographic features 492 CWUM/T1 (n=13) Modified Bondy (n=10) Sex (M:F) 6:7 5:5 Age (years old) 41.5 (20-54) 44.6 (15-59) Follow-up duration (months) 41.4 (6-110) 17.6 (6-40) Numbers as mean value (lowest-highest). CWUM/T1: canal wall up mastoidectomy with tympanoplasty type 1 and scutumplasty, modified Bondy: modified Bondy technique
Management of Attic Cholesteatoma Preserving Intact Ossicular Chain Shin DB, et al. 실함몰과고막후방함몰을막기위해얇은연골조각을모루뼈몸통과망치뼈놀이 (malleus head) 의내측면바닥에삽입하고, 또다른연골조각을모루뼈긴다리 (long process of incus) 와안면능선위에걸쳐두었다 (Fig. 1). 근막으로상고실과유돌동을덮어주고 Choi 등 11) 이제시한방법으로외이도확장성형술을시행하였다. 청력검사및고막소견모든환자들의수술전후고막과외이도상태를이내시경으로확인하였으며, 수술후최종관찰기간까지확인된이내시경소견으로고막함몰이나진주종재발등이상소견여부를비교하였다. 청력은기도역치 (air conduction threshold) 의경우 0.5~8 khz, 골도역치 (bone conduction threshold) 의경우 0.5~4 khz 에대한순음청력검사를실시하였고, 수술전과수술후 6~ 12개월사이에측정된결과를 4분법평균 (0.5, 1, 2, 3 khz) 을이용하여비교하였다. Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery의임상가이드라인에따라수술전후의골도- 기도차, 골도- 기도차감소량 [=( 수술전골도- 기도차 )-( 수술후골도- 기도차 )] 을비교하였다. 수술후골도- 기도차를 10 db 이하, 11~20 db, 21 db 이상으로분류하여수술군간에비교하였다. 통계분석은 IBM R SPSS R statistics ver. 21(SPSS Inc., Chicago, IL, USA) 을이용하였고 p<0.05 일경우의미있는결과로판정하였다. 수술전후변화는 Wilcoxon signed-rank test, 다른군간의비교는 Mann-Whitney U test, 2 3 교차분석은선형대선형결합을이용하여검정하였다. 결과 수술전두군의상고실함몰소견은공통적이었으나변형 Bondy술식을선택한환자에서대체로더광범위한함몰과파괴소견을보이는경향이있었다. 추적관찰기간동안술후문제점이확인된경우는 CWUM/ T1에서는 3예 (23.1%) 로상고실진주종재발 1예 (Fig. 2A), 고막긴장부유착 1예, 재발성삼출성중이염이 1예가관찰되었다. 변형Bondy 술식후에는경도의상고실함몰 1예와고막후방함몰 1예등총 2예 (20.0%) 에서문제가관찰되었다 (Table 2). 변형Bondy 술식이후재발성이루나좁은외이도등공동문제 (cavity problem) 는관찰되지않았다 (Fig. 2B). 두군간의수술전청력을비교했을때골도역치 (CWUM/ T1: 17.0±6.0 db, 변형Bondy 술식 : 15.8±10.9 db) 와기도역치 (CWUM/T1: 27.5±7.7 db, 변형Bondy술식 : 33.3±12.7 db) 는통계적인차이가없었다. 같은군내의수술전후골도- 기도차변화는 CWUM/T1 술식후에는 10.5±7.4 db에서 A B Fig. 1. Intraoperative microscopic view of modified Bondy technique. Canal wall down mastoidectomy is performed preserving ossicular chain intact (A). A piece of thin cartilage chip (arrow) is inserted under incus body and malleus head to prevent postoperative attic retraction and an additional thin cartilage chip (arrowhead) is draped over long process of incus and fallopian canal to prevent possible posterior pars tensa retraction (B). A B Fig. 2. Postoperative endoscopic view after left canal wall up mastoidectomy with tympanoplasty type I (A) and right modified Bondy technique (B). Crescent shape of recurrent attic retraction (arrows) is observed in front of cartilage plate used as scutumplasty ( * ) (A). A thin cartilage chip ( * ) placed over long process of incus to prevent pars tensa retraction is seen after modified Bondy technique (B). www.kjorl.org 493
Korean J Otorhinolaryngol-Head Neck Surg 2017;60(10):491-6 Table 2. Postoperative problems Postop status 6 months CWUM/T1 (n=13) Modified Bondy (n=10) Recurrent attic cholesteatoma 1 Attic retraction 1 Pars tensa adhesion 1 1 Postop recurrent OME 1 Total (%) 3 (23.1) 2 (20.0) CWUM/T1: canal wall up mastoidectomy with tympanoplasty type 1 and scutumplasty, modified Bondy: modified Bondy technique, OME: otitis media with effusion Table 3. ABG value before and after surgery (db HL) Surgery Preop ABG Postop ABG p-value ABG closure CWUM/T1 (n=13) 10.5±7.4 13.2±8.1 0.033* -2.69±3.79 Modified Bondy (n=10) 17.5±11.3 12.7±6.8 0.203 4.80±10.23 p-value 0.257 0.832 0.049* *indicates statistical significance (p <0.05), Wilcoxon signed-rank test for the same group, Mann-Whitney U test between two groups. CWUM/T1: canal wall up mastoidectomy with tympanoplasty type I and scutumplasty, modified Bondy: modified Bondy technique, ABG: air-bone gap, ABG closure: preoperative ABG-postoperative ABG 8 6 Postoperative air-bone gap Postop ABG 10 db Postop ABG 11-20 db Postop ABG 21 db 수술후골도- 기도차를 10 db 단위로분류해보면 CWUM/ T1군은 13예중 11예 (84.6%) 에서, 변형Bondy 군은 10예중 9 예 (90.0%) 에서 20 db 이하의골도- 기도차를보였다. 10 db 이하의골도- 기도차를갖는경우는 CWUM/T1 은 3예 (23.1%), 변형Bondy 군은 4예 (40.0%) 로변형Bondy 군에서더많았지만의미있는차이는없었다 (Fig. 3). 고 찰 Cases 4 2 0 3 CWUM with T1 Fig. 3. Postoperative air-bone gap expressed in 10-dB unit bins. In majority of cases, air-bone gap remains within 20 db after surgery in both groups. Percentage of accomplishing air-bone gap within 10 db is higher after modified Bondy technique than after canal wall up mastoidectomy without significant difference (p=0.415). 13.2±8.1 db 로의미있는차이를보이며증가하였다 (p=0.333). 변형 Bondy 술식후에는 17.5±11.3 db 에서 12.7±6.8 db 로감 소하였으나통계적차이는없었다. 두군간의수술후골도 - 기도차감소량도 CWUM/T1 군에서는 -2.69±3.79 db, 변형 Bondy 술식군에서는 4.80±10.23 db 로변형 Bondy 군에서 골도 - 기도차가더많이줄어들었으며두군간에의미있는 차이를보였다 (p=0.049)(table 3). 8 2 4 5 1 Modified Bondy 본연구는상고실진주종환자에서정상적인귓속뼈연쇄를유지한채수술한 CWUM/T1와변형Bondy 술식의성적을비교한결과이다. 상고실진주종수술에서정상적인귓속뼈연쇄를보존하게되면재건이쉽고, 수술후청력보존에유리하고, 빈상고실보다수술후상고실함몰관리가쉬운장점이있다. 12) 진주종이직접닿아있던귓속뼈에서진주종이재발할가능성도있지만정상적인귓속뼈연쇄를보존하면서수술하더라도재발률이상승하지않는다고알려져있다. 3,13) 저자들은상고실진주종수술시상고실파괴범위가커서순판성형술로재건하기어렵거나유양동의함기화가크지않으면개방공동술식을유양동의함기화가매우발달해있으면폐쇄공동술식및순판성형술을우선적으로고려하였다. 연구기간동안초기에는 CWUM/T1을우선적으로고려했으나 2008년이후에는변형Bondy 술식이좀더적극사용되었기에변형Bondy 술식군의수술후추적관찰기간이더짧다. 두군간의수술전청력은통계적인차이가없었으나변형 Bondy술식군의수술전평균기도역치및골도-기도차가 CWUM/T1군보다더컸다. 이는상고실파괴범위가큰환자 494
Management of Attic Cholesteatoma Preserving Intact Ossicular Chain Shin DB, et al. 에서변형Bondy 술식군을선택한것과연관이있을것으로추정된다. 외이도공명효과등을고려하면똑같이제1형고실성형술을시행하더라도개방공동보다는폐쇄공동술식의청력결과가더양호할것으로예상했으나반대의결과가관찰되었다. 즉, CWUM/T1 후골도- 기도차가수술전보다오히려증가하였고골도-기도차감소량측면에서도 CWUM/T1보다는변형 Bondy술식이더우수하였다. CWUM/T1 수술후골도- 기도차가더커진이유는분명하지않으나순판골결손을메우기위해사용한두꺼운이갑개연골판이일부증례에서망치뼈목 (malleus neck) 을압박하면서귓속뼈움직임을방해했을가능성이있다. 수술후출혈에따른상고실섬유화등도귓속뼈움직임을제한했을수있다. 반면, 전례에서골도- 기도차가 30 db 이내인것을고려하면과다한상고실점막제거로인한귓속뼈- 상고실덮개 (tegmen epitympani) 간의골융합이청력을악화시켰을가능성은적어보인다. 반면, 변형Bondy 술식후에는골도-기도차가감소하는경향을보였으며골도- 기도차가 10 db 이하로유지된경우도 CWUM/T1군보다비교적더많았다 (Fig. 3). 변형Bondy 술식에서망치뼈놀이와모루뼈몸통이이식근막에유착되어귓속뼈움직임이제한될가능성도있지만본대상자들에서는영향이미미했던것으로보인다. 이러한청각적호전변화는딱딱한가피형태로상고실을압박하던진주종이제거되면서귓속뼈의움직임이개선된것이이유가아닐까생각된다. 변형Bondy술식에서도상고실과고막후방함몰을막기위해상고실바닥과모루뼈긴다리외측에각각얇은연골조각을삽입하였다. CWUM/T1의순판성형술에사용된크고두꺼운연골판보다는변형Bondy 술식에사용된얇은연골조각들이귓속뼈움직임에영향을줄가능성이적어보인다. 귓속뼈연쇄가정상인경우유양돌기의함기화나외이도공명효과보다는귓속뼈의자유로운움직임을확보하는것이더중요하리라판단된다. 변형Bondy 술식의가장큰위험은회전중인천공기가모루뼈에직접접촉하여생기는감각신경성난청이며이를방지하기위해서는모루뼈외측의뼈다리를제거할때 3-mm diamond burr로계란껍질처럼얇게갈아낸뒤남은뼈는 pick 등으로조심스럽게제거하여귓속뼈손상을방지하는주의를기울여야한다. 본연구에서는변형Bondy 술식후골도역치가 10 db 이상악화된증례는없었다. 정상귓속뼈연쇄를가진상고실진주종에서또다른변형근치술식인 intact bridge mastoidectomy가변형bondy 술식의대안으로고려될수도있다. Intact bridge mastoidectomy 는개방공동의장점을가지면서뼈다리를보존하므로천공 기와유착으로부터귓속뼈연쇄를보호할수있는장점이있다. 그러나뼈다리를보존할경우상고실전체를노출시킬수없으므로진주종을남길우려가있고장기적으로함몰이발생할가능성이있다. 또한상대적으로높은안면능선이남아공동문제가생길수있으므로저자들은변형Bondy 술식의대안으로선택하지않았다. 술후이상소견을보인경우는 CWUM/T1에서는상고실진주종재발 1예를비롯하여 3예, modified Bondy군에서는얕은상고실함몰 1예를포함한 2예로두군간에큰차이가없었다. 수술방법에따른재발여부를비교하기에는본연구에사용된증례수가적고추적관찰기간이짧아더많은증례의외삽 (extrapolation) 을통해전체진주종성중이염에대한개방공동술식과폐쇄공동술식의임상경과를비교하여보기로하였다. 2001년부터 2015년까지같은병원에서진주종성중이염으로수술받은환자 344명중, 폐쇄공동술식 136 명, 개방공동술식 208명의의무기록을후향적으로비교하였다. 폐쇄공동술식후총 12예 (9.5%) 에서재수술을시행하였으며모두재발성진주종이원인이었다. 개방공동술식후 4예 (2.0%) 에서재수술을시행하였으며이중 1예는재발성진주종으로, 1예는좁아진외이도에의한공동문제, 2예는고막재천공으로수술을시행하였다. 폐쇄공동술식후생기는문제는고막긴장부유착및함몰 (14.7%), 상고실함몰 (11.8%), 삼출성중이염 (5.1%), 진주종재발 (3.7%), 재천공 (1.5%) 등의순으로총 36.8% 에서문제가관찰되었다. 개방공동술식후생기는문제는고막긴장부유착 (8.7%), 상고실함몰 (4.3%), 공동문제 (2.4%) 재천공 (1.9%), 연골염 (0.9%), 진주종재발 (0.05%), 두개저골수염 (0.05%) 등총 18.8% 에서문제가관찰되었다. 재수술빈도, 진주종재발, 기타수술후고막문제의발생빈도등수술후문제는개방공동술식이폐쇄공동술식에비해훨씬적었다. 재발성진주종, 수술후상고실함몰, 고막유착등의문제가처음확인된시기는폐쇄공동술식후평균 31.5개월, 개방공동술식후평균 36.5개월이었고 3~132 개월에걸쳐이상소견이발견되었으므로수술방식에관계없이수술후초기부터 10년이상장기간의추적관찰이필요한것으로보인다. 개방공동술식은뼈구조물을최대한편평하게제거하므로수술후국소적인재함몰의위험이낮고재함몰이나가피가발생하더라도상고실과고막후방이외이도로충분히노출되므로재수술없이외래처치만으로치료가능한경우가많다. 반면폐쇄공동술식은외이도공명효과를보존하는장점이있으나상고실과고막후방의재함몰이발생할경우보존적치료만으로해결하기힘든경우가많아재수술이종종요구된다. 문헌고찰에서도후천성일차진주종 (primary acquired cholesteatoma) 수술후 recidivism 발생률은개방공 www.kjorl.org 495
Korean J Otorhinolaryngol-Head Neck Surg 2017;60(10):491-6 동술식후 0~13.2%, 폐쇄공동술식후 16.7~61% 로보고되어 개방공동술식후 recidivism 이더적게발생하는것으로알 려져있다. 14) 개방공동술식의장점을가진변형 Bondy 술식은 한번의수술로수술전청력을보존하고재수술가능성을 줄일수있는좋은선택이된다. 정상귓속뼈연쇄를가진상 고실진주종에서유양돌기가크게함기화되어있지않은경 우라면변형 Bondy 술식은선택할수있는중요한술식으로 항상고려되어야할것이다. 이연구의제한점은연구에포함된환자수가적고, 변형 Bondy 술식군의경우추적관찰기간이상대적으로짧다는 것이다. 그러므로향후연구에서는이를보완하여더많은 환자를대상으로장기간추적관찰을해볼필요가있겠다. REFERENCES 1) Brown JS. A ten year statistical follow-up of 1142 consecutive cases of cholesteatoma: the closed vs. the open technique. Laryngoscope 1982;92(4):390-6. 2) Shirazi MA, Muzaffar K, Leonetti JP, Marzo S. Surgical treatment of pediatric cholesteatomas. Laryngoscope 2006;116(9):1603-7. 3) Nyrop M, Bonding P. Extensive cholesteatoma: long-term results of three surgical techniques. J Laryngol Otol 1997;111(6):521-6. 4) Tomlin J, Chang D, McCutcheon B, Harris J. Surgical technique and recurrence in cholesteatoma: a meta-analysis. Audiol Neurootol 2013; 18(3):135-42. 5) Kim CS, Chang SO, Lee SS, Hwang CH, Park JB, Won TB. Follow up hearing and complication results of the two surgical techniques in the treatment of adult cholesteatoma. Korean J Otolaryngol-Head Neck Surg 2001;44(10):1043-7. 6) Woo HY, Sohn JH, Cho KR, Kim HK, Kim JY. Clinical features of cholesteatoma in the normal hearing ear. Korean J Otorhinolaryngol- Head Neck Surg 2008;51(10):861-5. 7) Kim MB, Choi J, Lee JK, Park JY, Chu H, Cho YS, et al. Hearing outcomes according to the types of mastoidectomy: a comparison between canal wall up and canal wall down mastoidectomy. Clin Exp Otorhinolaryngol 2010;3(4):203-6. 8) Naguib MB, Aristegui M, Saleh E, Cokkeser Y, Russo A, Sanna M. Surgical management of epitympanic cholesteatoma with intact ossicular chain: the modified Bondy technique. Otolaryngol Head Neck Surg 1994;111(5):545-9. 9) Sanna M, Facharzt AA, Russo A, Lauda L, Pasanisi E, Bacciu A. Modified Bondy s technique: refinements of the surgical technique and long-term results. Otol Neurotol 2009;30(1):64-9. 10) Hwang E, Lim HJ, Lee HB, Kim SY, Park K, Park HY, et al. Clinical usefulness of modified Bondy operation for management of cholesteatomas. Korean J Audiol 2011;15(2):72-5. 11) Choi IJ, Song JJ, Jang JH, Chang SO. A novel meatoplasty method in canal wall down tympanomastoidectomy: a perichondrial posterior fixation technique. Clin Exp Otorhinolaryngol 2009;2(4):164-8. 12) Tos M. Manual of middle ear surgery. New York: Thieme Medical Publisher, Inc.;1995. p.432. 13) Lau T, Tos M. Tensa retraction cholesteatoma: treatment and longterm results. J Laryngol Otol 1989;103(2):149-57. 14) Kerckhoffs KG, Kommer MB, van Strien TH, Visscher SJ, Bruijnzeel H, Smit AL, et al. The disease recurrence rate after the canal wall up or canal wall down technique in adults. Laryngoscope 2016;126(4): 980-7. 496