대 한 방 사 선 의 학 회 지 1992 ; 28 ( 1) : 4 7~ 50 Journal 01 Korean Radiological Society, January, 1992

CT Findings of Automastoidectomy*

Hyung Jin Kim, M.D. , Hae Gyeong Chung, M.D. , Jae Hyoung Kim, M.D. , Eui Gee Hwang, M.D.** , Yong Woon Ma, M.D.** , Sung Hoon Chung, M.D.

Department of Radíology, College of Medícine, Gyeongsang Natíonal Uníversíty

- Abstract-

Cholesteatoma of the middle ear and mastoid sometimes destroys the posterior wall of the external auditory

canal(EACJ, and this phenomenon is termed as “ automastoidectomy" . During the past two years the authors reviewed

the CT features of automastoidectomy in eight patients with middle ear cholesteatoma. There was a variable amount

of the cholesteatomatous mass or debris within the mastoid cavity in all patients , of whom air collection was found

in fou r. Interestingly. the site and pattem of the erosion of the EAC were nearly identica1 between patients with

a ir in the mastoid cavity and those without it. Air in the mastiod cavity was the only clue of the expulsion of the

cholesteatoma. So. we think that the expulsion of the cholesteatoma might be pred,icted when the erosion of the

EAC is present in patients with cholesteatoma in the mastoid cavity. CT clearly depicted associated complications

caused by the cholesteatoma. such as ossicular destruction (n; 8 ), the eroion of the facial nerve canal (n; 2) . the

erosion of the lateral semicircular canal (n;2) . the erosion of the tegm en (n; 1). the erosion of the sigmoid sinus

plate (n; 1). the erosion of the superior semicircular canal (n; 1), and the erosion of the vestibule (n; 1).

Although much of the natura l history of the middle ear cholesteatoma still rema ins to be determined . we think

that careful evaluation of one type of possible progression of the disease will help us understand its clinical course .

Moreover. our findings strongly support the use of CT for evaluation of “ automustetomy ‘. seen in many cases of

cholesteatomá

Index Words: Ear. CT 2 1. 1211

Tempora l bone ‘ CT 2 1. 1211

Cholesteatoma 2 1.264

Since the advent and the technical development dings of “ automastoidectomy’‘ in eight patients with

of computerized tomography(CT j, it has proved to be middle ear cholesteatomas.

th e most effective method for evaluating

c holesteatoma of the middle ear(l -13) . Sometimes. MATERIALS AND METHODS

the mastoid bone forming the posterior wall of the

external auditory cana l(EAC) (Fig. 1) is destroyed by During the last two years. we retrospectively

an adjacent cholesteatoma. This leads to a so-called analized CT of 44 patients with surgically proved

“ automastoidectomy". commonly resulting in spon- cholesteatomas. Among them. eight patients show-

taneous drainage of the cholesteatoma through th e ed erosion of th e posterior wall of the EAC. In this

EAC. Despite numerous reports on the CT findings group there were two m en a nd six women ‘ agesrang-

of the middle ear cholesteatoma. only a few a rtic1es ing from 20 to 53 years(mean. 36yrs). The chief com-

concerning “ a utomastoidectom y " are found in the plaint was otorrhea in five and otalgia in two. and all

literature(4.1 3 .14). The a uthors evaluated the CT fin- patients had a variable degree of conductive h earing

*이 논문은 1991년도 경상대학교병원 임상연구비의 일부 지원으로 이루어졌음

**경상대학교 의과대학 이비인후과학교실

** Department of Otolaryngology. College of Medicine. Gyeongsang NationaJ University

이 논문은 1991년 7월 20일 접수하여 1991년 11월 14일에 채택되었음 Received July 20. Accepted November 14. 199 1.

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Journal of Korean Radiological Society 1992 ; 28( 1) : 47~50

loss. All patients were preoperatively examined by erosion of the EAC were nearly identical between pa -

a 9800 scanner(GE Medical System. Milwaukee) with tients with air in the mastoid cavity and those without

1.5mm collimation and with high-resolution bone it. Air in the mastiod cavity was the only clue of the

algorithm. 80th direct axial and coronal scans were expulsion of the cholesteatoma. All patients had

obtained. We particularly paid attention to the follow- ossicular destruction either totally or partially. Other

ing features: 1) site and pattern of the erosion of the complications caused by cholesteatoma were the ero-

bony EAC; 2) presence or a bsence of cholesteatoma sion of the facial nerve canal (n = 2). the erosion of the

within the mastoid cavity. and if present. its distribu- lateral semicircular canal (n = 2) . the erosion of the

tion pattern; 3) presence or a bsence of air within the tegm en (n = 1). the erosion ofthe sigmoid sinus plate

mastoid cavity. and if present. its distribution pattern ; (n = 1). the erosion of the superior semicircular canal

and 4) other complications of cholesteatoma. (n = 1). a nd the erosion of the vestibule (n = 1)

RESULTS DISCUSSION

The s ite of erosion of the EAC was mos t1y at the “ Automastoidectomy" is an uncommon but

posterosuperior aspec t. seen in six patients . In two rather unique complication of cholesteatoma of the

patients nearly the entire EAC was eroded . In six pa- middle ear(4) . It can be defined as the destruction of

tients. the adjacent scutum was concomitantly erod- the mastoid bone forming the posterior wall of the

ed . Although the pattern of the erosion was either EAC by the adjacent cholesteatoma in patients with

smooth or irreg비ar. it showed a lobulated appearance no history of previous operation. Spontaneous

in all patients. The cholesteatomatous mass or debris drainage of the cholesteatoma through the bone

was present in all eight patients . Its pattern of defect may ensue. This self-treatment may be e ither

distribution within the mastoid cavity was c ir- comple te or incomplete. In the complete form. the

cumferentiaJ in three(Fig. 2) . and total filling in self-cleaned a nd well-ventilated mastoid cavity is

four (Fig. 3). Near total filling was encountered in one r e miniscent of “ open canal' ’ type mastoid-

case except in some parts adjacent to the site of the ectomy(Fig. 4) . In the incomplete form . the residual

defect of the EAC. Air within the mastoid cavity was or unexpelled cholesteatoma still remains in the

seen in four patients(Fig. 2) among whom it was cen- mastoid cavity(Fig. 3 ). Strictly speaking. all of the

tral in three and periphera l a이acent to the site of the eight cases in this report belonged to the incomplete

defect of the EAC in one. The site a nd pattern of the form. in that there was a variable amount of the

1 2a 2b

Fig_ 1. Normal EAC. The EAC is formed by the tympanic bone anteriorly and the mastoid bone posteriorly . Fig_ ::!. Automastoidectomy The axia l(a) and coronal(b) CT scans of the left temporal bone show a typical bone defect of the EAC at its posterosuperior aspect with a direct communication between the EAC and the aerated mastoid cavity. Most of the cholesteatoma has been expelled through the bone defec t. Note the small amount of the shell-like remnant of the cholestesteatoma within the mastoid cavity in a circumferential fashion(arrows).

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Hyung Jin Kim , et al CT Findings of Automastoidectomy

3 4 5

Fig. 3. Automastoidectomy. The axial CT scan demonstrates the posterior wall defect of the EAC. The cholesteatoma has not been expelled. but wholely resides in the mastoid cavity which contains no air Fig. 4. Open-canal mastoidectomy. The axial CT scan showes the defects at the posterior wall of the EAC as well as the lateral wall of the mastoid bone in this patient with a history of mastoidectomy six years ago. There is a recurrent cholesteatoma within the mastoid cavity. Compare these findings with those of Fig. 2 Fig. 5. Impending a utomastoidectomy. The axial CT scan shows an expansile antral cholesteatoma thining the posterior wall of the EAC by pressure ero­sion(arrowheads). In authors' mind it would be followed by “ automastoidectomy" which might occur sooner or later.

cholesteatomatous mass or debris remaining in the Moreover, our findings strongly support the use of CT

mastoid caviy. for evaluation of “ automustetomy" seen in many

Presence ofair in the mastoid cavity may be used cases of cholesteatoma.

as an evidence that the cholesteatoma. either in its

part or entirety. has gone ou t. As shown in this study ,

despite the similarities in the site and pattern of the

erosion of the EAC , in all of four patients without

mastoid air , the cholesteatoma filled the e ntire

mastoid cavity. On the other hand , those with

mastoid air , there was a variable amount of a loss of

the cholesteatoma seen in the mastoid cavity. 50 , we

think that the expulsion ofthe cholesteatoma might

be predicted when the erosion of the EAC is present

in patients with cholesteatoma in the mastoid cavity.

While we reviewed CT of patients with middle ear

cholesteatoma, we encountered an interesting finding

in several patients. In them. the expansile antral

cholesteatoma thinned the posterior wall ofthe EAC

by presure erosion. as commonly noted in a sinus

mucocele , but not to the degree of frank destruction

as seen in the cases of “ automastoidectomy" (Fig. 5)

It seems reasonable to assume that “ automastoidec­

tomy" would follow sooner of later

In conclusion . as a part of complications of the

middle ear cholesteatoma. “ automastoidectomy"

does occur not uncommonly. We think that carefu l

evaluation of one type of possible progression of the

disease will help us understand its c linical course.

REFERENCES

1. Proctor B. Chronic otitis media a nd mastoiditis. In

Paparella MM ‘ Shumrick DA. eds. Otolaryngology

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pany ‘ 1980: 1455-1489

2. Mafee MF , Levin BC. Applebaum EL , Campos M‘

James CF. Cholesteatoma of the middle ear and

mastoid: A comparison of CT scan and operative fin­

dings. Otolaryngol Clin North Am 1988:22( 1):

265-293

3. Johnson DW , Voorhees RL. Lufkin RB. Hanafee W.

Canalis R. Cholesteatomas of the temporal bone:

Role of computed tomography. Radiology 1983:

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4. Johnson DW. Hinshaw DB Jr .. Hasso AN ‘ Thomp­

son J R. Stewart CE. Computed Tomography oflocal

complications of temporal bone cholesteatomas. J

Comput Assist Tomogr 1985 ‘ 9(3):519-523

5. Swartz JD. Cholesteatomas ofthe middle ear. Radiol

Clin North Am 1984:22: 15-35

6. Virapongse C. Rothman SLG , 5asaki C. Kier EL. The

role of high resolution computed tomography in

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Journal of Korean Radiological Society 1992 ; 28( 1) : 4 7~50

evaluating disease of the middle ear. J Comput bone: Evaluation with CT and MR. Seminars in

Assist Tomogr 1982;6(4):711-720 Ultrasound. CT and MR 1989;10(3):213-235

7. Mafee MF. Kumar A. Yannias DA. Valvassori GE. 11. Swartz JD. Goodman RS. Russell KB. Marlow FI.

Appelbaum EL. Computed tomography of the mid- Wolfson RJ. High-resolution computed tomography

dle ear in the evaluation of cholesteatomas and other of the middle ear and mastoid . Part 2: Tubotym-

soft tissue masses: Compaπson with pluridirectional panic disease. Radiology 1983; 148:455-459

tomography. Radiology 1983; 148:465-472 12. Johnson DW. CT ofthe postsurgical ear. Radiol Clin

8. Mafee MF. Aimi K. Kahen HL. Valvassori GE. Capek North Am 1984;22(1):67-75

V. Chronic otomastoiditis: A conceptual understan- 13. Kim HJ. Chung HK. Gong JC. et a l. CT of

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9. Swartz JD. Varghese S. Pars f1accida cholesteatoma Korean Radiol Society 1990;26(6): 1104-1115

as demonstrated by computed tomography. Arch 14. Nardis PF. Teramo M. Giunta S. Bellelli A. Unusual

Otolaryngol 1984; 110:515-517 cholesteatoma shell: CT findings . J Comput Assist

10. Holliday RA. In f1ammatory diseases of the temporal Tomogr 1988: 12(6): 1084-1085

<국문 요약〉

자연유돌절제술의 전산화단층촬영 소견

경상대학교 의과대학 방사선과학교실， 이비인후과학교실*

김형진 • 정혜경 • 김재형 • 황의기** • 마용운** • 정성훈

저자들은 지난 2년간 경상대학교병원에서 수술로 확진된 중이 진주종 환자중 자연유돌절제술의 소견을 보인 8례의 CT

소견을 분석하였다. 8례 모두에서 다양한 정도의 진주종이 유돌강(mastoid cavity) 내에서 관찰 되었으며 이중 4례에서

공기음영이 유돌강에서 보였는데 공기음영의 유무와 관계없이 외이도 후벽의 골파괴는 거의 유사한 양상으로 나타났다.

차이점은 단지 얼마 만큼의 진주종이 외이도를 통하여 바깥으로 자연 배출되었느냐 하는 것이었다. CT는 또한 진주종에

동반된 다른 합병증을 아는 데에도 매우 유용하였다.

결론적으로1 중이 진주종의 다양한 임상경로의 하나로서 나타나는 자연유돌절제술을 인지합은 진주종의 자연경과를 이

해하는데 일조를 할 것으로 생각되며 CT는 이런 병변을 밝히는데 가장 유용한 방법이 될 것이다.

- 50-