KISEP Rhinology Koean J Otolaryngol 1998;4112:155-1556 전두개저에대한전사골관의해부학적관계 : 전산화단층촬영에의한사골와의유형별분석 홍순관 1 엄준형 1 변성완 1 김종남 1 김춘동 1 정승용 1 장주애 1 최혜영 1 Anatomical Relationship of the Anterior Ethmoid Canal to the Anterior Skull Base A Computed Tomographic Analysis on the Types of the Fovea Ethmoidalis Soon Kwan Hong, MD 1, Jun Hyung Eum, MD 1, Sung Wan Byun, MD 1, Chong Nahm Kim, MD 1, Chun Dong Kim, MD 1, Seung Yong Chung, MD 1, Ju Ae Chang, MD 1 and Hae Young Choi, MD 2 1 Department of Otolaryngology and 2 Radiology, College of Medicine, Ewha Womans University, Seoul, Korea ABSTRACT Background and ObjectivesAs the anterior ethmoid canal AEC provides a good surgical landmark and its injury may result in serious complications, the anatomical relationship of the AEC to the anterior skull base ASB should be evaluated preoperatively. Despite some studies on the ASB, studies analyzing this anatomical relationship and the types of the fovea ethmoidalis FE on computed tomography CT are rare. The aim of this study is to better understand this anatomical relationship by determining the frequency of each type of the FE and distances between anatomical structures on the CT scans with our new classification. Materials and MethodFour hundred sides of the FE were analyzed from the preoperative coronal CT scans of 2 chronic sinusitis patients 1 males and 1 females, aged 2 to 59 years. The FE was classified into 4 types non-separated type, partially separated type, completely separated type, unidentifiable type and 2 subtypes Adeveloped medial cranial wall, Bundeveloped medial cranial wall). Heights of the medial cranial wall a, the AEC b, and the ethmoid roof c were measured on the CT image. ResultsFrequencies of the types - were 48.% A25.2%, B22.8%, 19.3% A4.3%, B15.%, 29.5% A29.5%, B %, and 3.2%, respectively. The medial cranial wall of type A was significantly longer than those of the other types, and the AEC of type A was in a significantly lower position than those of the other types. ConclusionOn the CT scans, we found the AEC in 96.8% and type A in nearly 3% of all types of the FE. Sinus surgery should be performed only after preoperative evaluation of these anatomical relationship on the CT scans under close scrutiny. For the type A, surgery should be performed with utmost care due to high risk of injury to the AEC and the medial cranial wall. Korean J Otolaryngol 1998;4112:155-1556 KEY WORDSAnterior ethmoid canal Anterior skull base Computed tomography Fovea ethmoidalis. 155
Fig. 1. Schematic drawings showing the 3 different types,, and 2 subtypes A, B of the fovea ethmoidalis according to the anatomical relationship of the anterior ethmoid canal to the anterior skull base. The fovea ethmoidalis where the anterior ethmoid canal is unidentifiable on CT scans is classified as type. Note variations of heights of the medial cranial wall a, the anterior ethmoid canal b, and the ethmoid roof c. The length of b is a vertical distance from the cribriform plate to the point where the anterior ethmoid canal enters the anterior skull base, and the length of c is a vertical distance from the cribriform plate to the point where the ethmoid roof meets the orbit Type nonseparated type, Type partially separated type, Type completely separated typesubtype Aa subtype where the medial cranial wall is developed, Subtype Ba subtype where the medial cranial wall is undeveloped. 1551
전두개저에 대란 전사골관의 해부학적 관계 를 나와 주행도중 사골동천장으로 부착되는 부분분리형, 를 구한 후, 유형별 빈도의 남녀간 차이는 χ2-test로 분석하 Ⅲ형 전사골관이 안와를 나와 사골동천장에 부착되지 않 였고 각 계측치의 남녀간 차이는 t-test로 분석하였으며 각 고 주행한 후 후각와로 들어가는 완전분리형, Ⅳ형 CT상 유형간의 계측치의 차이는 ANOVA test로 분석하였다. 또한 에서 전사골관을 확인할 수 없는 형)으로 분류하고, 다시 좌우측이 같은 유형인 환자와 다른 유형인 환자의 빈도를 조 Ⅰ-Ⅲ형을 두개내벽(medial cranial wall) 발달유무에 따 사한 후 두 경우의 빈도간에 유의한 차이가 있는 지를 bino- 라 2가지 아형(A아형 두개내벽이 발달한 경우, B아형 mial test로 분석하였다. 통계적 분석은 SAS program 두개내벽이 발달하지 않은 경우)으로 재분류하였다(Fig. (version 6.3)을 이용하였고 유의수준은 모두 5%로 하였다. 1). 두개내벽 발달유무를 구별하기 어려운 경우는 다음과 Table 1. Frequency of the types of the fovea ethmoidalis according to the anatomical relationship of the anterior ethmoid canal to the anterior skull base 같이 구별하였다. 사골동천장이 사판으로 이행하는 과정에 Frequency 약간의 각이라도 존재하면 그 외측은 사골동천장, 내측은 두개내벽으로 판단하고 이러한 각이 없이 점진적으로 이행 Type 하면 전체를 사골동천장으로 간주하여 두개내벽이 발달하 Ⅰ 지 않은 형으로 판단하였다. 또한 각 유형에 있어서 첫째, 두개내벽의 높이(a), 둘째, 전사골관의 높이, 즉 사판으로 안와와 만나는 지점까지의 높이(c)를 위 그래픽 프로그램 (version 7.)으로 환산하여 구하였다(Fig. 1). 계측을 일 정하게 하기 위하여, 전사골관이 전두개저로 들어가는 관 상면 영상에서 위 거리들을 측정하였다. 각 유형별로 그 빈도, a, b, c 계측치의 평균과 표준편차 IA IB 1552 IIA IIB 89( 44.5%) 13( 51.5%) 192( 48.%) B 4(2.%) 51(25.5%) 47( 23.5%)* B Ⅳ (N 4) 52(26.%) 15( 7.5%)* 32(16.%) 58(29.%) Ⅲ 을 이용하여 좌표로 측정한 후, Microsoft Excel program (N 2) 49(24.5%) A 셋째 사골동천장의 높이, 즉 사판으로부터 사골동천장이 A Ⅱ 부터 전사골관이 전두개와로 들어가는 지점까지의 높이(b), (N 2) 3( 15.%)* 2( 1.%)* 28(14.%) 6( 3.%) A 58(29.%) 6(3.%) B (.%) (.%) 6( 3. %) 7( 3.5%) 11(25.2%) 91(22.8%) 77( 19.3%) 17( 4.3%) 6(15.%) 118( 29.5%) 118(29.5%) (.%) 13(3.2%) Total 2(1.%) 2(1.%) 4(1.%) *Differences between the frequencies in male and female are statistically significant in the type Ⅱ and ⅡA, respectively (p<.5, χ2-test). IIIA Fig. 2. The coronal plane computed tomographs showing the 3 different types (Ⅰ, Ⅱ, Ⅲ) and 2 subtypes (A, B) of the fovea ethmoidalis. Arrows indicate the anterior ethmoid canals. Type ⅢB was not found in this study. Korean J Otolaryngol 1998;41(12):155-1556
Table 3. Frequency of subjects in whom both sides of the fovea ethmoidalis are of the same or different types Male N=1 Female N=1 Total N=2 Of same type 5656.% 6565.% 1216.5% Of different type 4444.5 3535.% 7939.5% *Differences between the frequencies of both types are statistically significant in female and in total, respectively p.5, binomial test. 1553
Table 2. Heights of the medial cranial wall a, the anterior ethmoid canal b, and the ethmoid roof caccording to the types of the fovea ethmoidalis, measured on the coronal computed tomography scans Height a mm b mm c mm Type N2 N2 N4 N2 N2 N4 N2 N2 N4 A 4.481.27 4.291.3 4.391.15 4.541.27 4.441.46 4.491.36 4.541.27 4.441.46 4.491.36 1.777.6 1.777.6 1.777.6 1.777.6 1.7711.76 1.7711.76 1.777.6 1.7711.76 1.7711.76 B 3.711.36 3.781.52 3.751.45 3.711.36 3.781.52 3.751.45 1.187.6 1.189.41 1.189.41 1.187.6 1.189.41 1.189.41 A 3.81.2 4.121.66 3.841.4 5.761.86 6.182.91 5.811.89 11.13.3 8.243.33 1.763.33 2.355.29 2.945.29 2.355.29 2.358.82 4.128.24 2.358.82 2.9417.6 5.881.61 2.9417.6 B 3.271.8 3.341.61 3.31.34 1.874.47 9.13.48 1.84.1 1.185.88 1.778.24 1.188.24 6.4727.6 4.712.6 4.7127.6 A 6.71.46* 6.411.3* 6.561.38* 3.11.3 2.63.83 2.87.96 11.544.14 8.972.7 1.243.7 4.128.82 2.949.41 2.949.41 1.185.29 1.185.29 1.185.29 4.7122.94 4.1217.12 4.1222.94 Average of Subtype A 5.481.76 5.371.61 5.431.7 4.11.54 3.51.52 3.771.55 8.674.62 6.853.16 7.634.39 1.778.82 1.779.41 1.779.41 1.188.82 1.1811.76 1.1811.76 1.7722.94 1.1817.12 1.7722.94 Subtype B 3.511.24 3.631.55 3.571.42 6.894.72 5.693.5 6.284.16 1.187.6 1.189.41 1.189.41 1.1827.6 1.182.6 1.1827.6 Total 3.442.99 3.162.92 3.32.96 3.821.45 3.551.53 3.691.5 8.14.73 6.373.35 7.24.18 8.82 9.41 9.41 1.188.82 1.1811.76 1.1811.76 1.18 27.6 1.182.6 1.1827.6 *The value of a in the type A is significantly higher than those in the other types in male, female, and total, respectively p.5, ANOVA, the value of b in the type A is significantly higher than those in the other types, and the value in the type A is significantly higher than those in the other types but lower than that in the type A p.5, ANOVA., the values of b in the type B and A are significantly lower than those in the other types p.5, ANOVA., the value of b in the type A is significantly higher than those in the other types, and the value in the type A is significantly higher than those in the other types but lower than that in the type A p.5, ANOVA. The values of c in the type A and B are significantly lower than those in the other types in male, female, and total, respectively p.5, ANOVA. The values of b and c in the type A of male are significantly higher than those of female, respectivelyp.5, ANOVA. 1554 Korean J Otolaryngol 1998;4112:155-1556
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