Correlation between microtia and temporal bone malformation evaluated using grading systems.
OBJECTIVE
To evaluate the relationships between temporal bone abnormalities and the severity of microtia in Japanese patients using objective grading systems.


METHODS
Retrospective case series study conducted between 1992 and 2003.


METHODS
Academic, tertiary care, referral medical center.


METHODS
One hundred forty-two ears of 109 Japanese patients (85 male and 24 female patients; mean age, 12.8 years [range, 2-36 years]) with microtia.


METHODS
The severity of microtia was classified according to Marx classification. Developmental abnormalities of the temporal bone were evaluated by a computed tomographic (CT) scoring system modified after the system used by Jahrsdoerfer and colleagues, using high-resolution CT scans of the temporal bone. Correlations between the scores obtained from these 2 grading systems were evaluated using a nonparametric statistical method.


RESULTS
Male preponderance and incidence of bilateral cases of approximately 30% were observed in our Japanese patients with microtia. There was no significant difference in the severity of microtia between unilateral and bilateral cases. The mean +/- SEM total points in the CT scoring system (full marks, 10) was 7.9 +/- 0.4 for grade I microtia, 6.6 +/- 0.6 for grade II, and 6.4 +/- 0.3 for grade III; the total points correlated inversely with the microtia grade. Development of the auricle correlated significantly with aeration in the middle ear spaces but not with ossicular development or formation of the oval/round windows. Proportion of acceptable surgical candidates according to the CT scoring system (>5 points) was 79% for grade I microtia, 52% for grade II microtia, and 65% for grade III microtia.


CONCLUSIONS
The principle "the better developed the auricle, the better developed middle ear" was confirmed in Japanese patients with microtia; however, even with grade II/III microtia, more than half of the patients were considered suitable for atresia surgery.
Ishimoto
Shin-Ichi
S
Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. shinchan-tky@umin.ac.jp
Ito
Ken
K
Yamasoba
Tatsuya
T
Kondo
Kenji
K
Karino
Shotaro
S
Takegoshi
Hideki
H
Kaga
Kimitaka
K
D000015:Abnormalities, Multiple; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004431:Ear, External / Q000002:abnormalities*; D004432:Ear, Middle / Q000002:abnormalities; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013701:Temporal Bone / Q000002:abnormalities*