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J Korean Orthop Assoc 2007; 42: 24-31 선천성근성사경환자의두개안면비대칭 - 두부방사선계측촬영을이용한분석 - 이동연송병욱조태준최인호정진엽유원준 Craniofacial Asymmetry in Congenital Muscular Torticollis Patients - A Study using Cephalometry - Purpose: To propose an objective method for evaluating the craniofacial asymmetry in congenital muscular torticollis patients, and to determine the correlation between the craniofacial asymmetry and clinical parameters such as age and the limitation of neck motion. Materials and Methods: Forty eight patients with congenital muscular torticollis, who underwent cephalometry for an evaluation, were enrolled in this study. The craniofacial curvature on the coronal plane, calvarial asymmetry, and mastoid process length were analyzed on the radiograph of the cephalometry. These radiographic measurements were analyzed to determine the correlation between the craniofacial asymmetry and clinical parameters. Results: The craniofacial axis was tilted to the affected side by 5.2 o ±2.8 o. The skullbase axis was tilted to the affected side by 2.6 o ±2.6 o, and the mandible axis was tilted to the affected side by 1.0 o ±2.3 o. The difference in the mastoid process length from the skullbase was 7.0%±8.5%. The calvarial width from the vertical midline was 15.4%±11.6% larger in the affected side. In patients older than 5 years, the mandibular tilting angle (p=0.017) and the length of the mastoid process (p=0.007) were greater than those of the younger patients. Conclusion: We proposed a new objective method for quantifying the craniofacial asymmetry in congenital muscular torticollis patients. This method confirmed the patients to have an angular deformity and asymmetry in the craniofacial bone. Key W ords: Congenital muscular torticollis, Cephalometry, Craniofacial asymmetry 서론선천성근성사경은흉쇄유돌근의편측성구축에의하여머리가동측으로기울고얼굴은반대측으로회전되는질환으로진단이지연되었거나적절한치료를받지못할경우이차적인변형으로두개골과안면부의비대칭현상이유발될수있다 2,5). 여러저자들은두개안면비대칭이존재하여도 3세이 통신저자 : 조태준서울시종로구연건동 28 서울대학교어린이병원정형외과 TEL: 02-2072-2878 FAX: 02-745-3367 E-mail: tjcho@snu.ac.kr * 본논문의요지는 2005 년도대한정형외과학회추계학술대회에서발표되었음. 전에수술을시행하면많은경우에비대칭이호전될수있다고보고하였다 2-4,14). 그러나두개골은장관골과달리비정형적인구조로되어있고각종지표를방사선검사상확인하기도어렵기때문에수술전두개골변형을정량화하고수술후그변화를측정하는것에어려움이있었다. 또, 선천성근성사경때문에고개를기울이고돌린상태로있기때문에두개골단순방사선검사를해 Address reprint requests to Tae-Joon Cho, M.D. Department of Orthopedic Surgery, Seoul National University Children's Hospital, 28, Yeongeon-dong, Jongno-gu, Seoul 110-744, Korea Tel: +82.2-2072-2878, Fax: +82.2-745-3367 E-mail: tjcho@snu.ac.kr 24

25 도두개골의촬영위치가표준화되어있지않아재현성있는측정이어려웠었다. 선천성근성사경에동반된두개안면비대칭에대해 Hollier 등 6) 은두부방사선계측촬영 (cephalometry) 및의학실물사진을이용해서 16명의선천성근성사경환자를대상으로결과를발표하였으나좌우의비대칭유무로만변형을기술하였으며, 현재까지두개안면비대칭을객관적으로정량화하는방법의표준으로정립된방법이없는실정이다. 본연구의목적은선천성근성사경환자에서동반된두개안면비대칭을객관적인방법으로측정하는방법을제시하고연령및경부운동범위등의임상인자와의관련성을분석하고자하였다. 대상및방법 1. 연구대상선천성근성사경으로 2003년 3월부터 2005년 3월까지수술적치료를예정하고두부방사선계측촬영을시행한 48명을대상으로하였다. 남자 39예, 여자 9예였으며병변은우측이 28예, 좌측이 20예였다. 45명의환자는흉쇄유돌근절제술 ( 단극성유리술 12예, 양극성유리술 33예 ) 을시행하였으며 3세이하의환자중 3명은지속적인물리치료로호전되어수술적치료를시행하지않았다. 본연구는서울대학교병원의학연구윤리심의위원회에서허가받았으며환자및보호자로부터동의를받았다. 2. 연구방법모든환자에서이학적검사를시행하여경부운동범위는좌우회전운동범위및측방굴곡범위의합을구하여좌우차이를기록하였다. 단순방사선촬영으로경부방사선촬영, 두부방사선계측촬영을시행하였다 (Table 1). 두부방사선계측촬영은양측외이도를잇는선을수평선으로하고두개골을고정한상태에서두개골을후전면으로단순방사선촬영하는것이다 (Fig. 1). 두부방사선계측촬영을객관적으로분석하기위해 Kim 등 9) 이제시한계측지표에추가하여새로운계측지표를다음과같이정의하였다. 먼저관상면 (coronal plane) 상에서두개안면의만곡변형을양측외이도 (external auditory meatus) 를연결한선과측두골추체부 (petrous part) 의 상연및양측하악각 (angle of mandible) 을지나는선이이루는각도를각각두개골기저부경사각 (skullbase tilting angle), 하악경사각 (mandibular tilting angle) 이라하였다 (Fig. 2A). 그리고시상봉합 (sagittal suture) 과비중격 (nasal septum) 을잇는선과비중격 (nasal septum) 과하악 (mandible) 의앞니 (incisor) 사이를지나는선이이루는각을두개안면경사각 (craniofacial tilting angle) 이라하였다 (Fig. 2B). 양측유양돌기의크기차이를평가하고자측두골추체부상연에서부터유양돌기말단까지의길이를측정하여양측간의차이를건측의거리로나누어백분율로표시하였다 (Fig. 2C). 두개및안면부의좌우비대칭정도를비교하고자양측외이도를지나는선에서비중격을지나는수직선 (vertical midline) 을긋고이로부터양측두정골 (parietal bone) 까지의길이의차이를건측의거리로나누어백분율로표시하고두개비대칭 (calvarial asymmetry from vertical midline) 이라고하였다 (Fig. 2D). 그리고비중격과하악의앞니사이를지나는선으로부터양측측두골추체부말단까지길이를측정하여양측간의차이를건측의거리로나누어백분율로표시하고두개골기저부비대칭 (skullbase asymmetry) 으로정의하였다. 같은방법으로양측하악각간의거리차이를건측의거리로나누어백분율로표시하고하악비대칭 (mandibular asymmetry) 으로정의하였다 (Fig. 2E). 또한각측정지표의재현성 (reproducibility) 를확인하기위해연속변수를구간으로나누고, kappa 통계처리 (kappa statistics) 을이용하여관찰자내신뢰도 (intraobserver reliability) 및관찰자간신뢰도 (interobserver reliability) 을측정하였다. 신뢰도는 Landis와 Koch 10) 의기준에맞추어, kappa 수치가 0.60 이상인경우상당한신뢰도 (substantial reliability) 가있는것으로판단하였다. 각각의환자에서측정된수치의평균과표준편차를구하고환자의연령과경부운동범위가이들과상관관계가있는지통계분석하기위해 5세미만인군 22명과 5세이상인군 26명으로나누어이들군을비교하였다. 또한, 좌우경부운동범위 ( 회전운동및측방굴곡운동의합 ) 의차이가 50 o 미만인군과 50 o 이상인군으로나누어이들군을비교하였다. 이들군간의비교를위해 T-test 를사용하였으며 p값이 0.05 미만인경우를통계적유의수준으로하였다. 그리고보다세부화된비교분석을위해

26 Table 1. Patients Data Mastoid Calvarial process Difference Skullbase Mandibular Craniofacial asymmetry length Skullbase Mandibular Affected of neck tilting tilting tilting from Patient Age Sex difference asymmetry asymmetry side motion angle angle angle vertical from (%) (%) (degree) (degree) (degree) (degree) midline skullbase (%) (%) 1 1 Male Right 0 0 0-2.1 1.1 6.0 5.3 1.4 2 1 Male Left 45 0-2.3 8.7-7.8 23.2 18.3 17.0 3 1 Male Right 60 2.4 0.5 4.3 0.0 36.9 29.0 24.4 4 1 Male Right 90 6.1 1.4 7.6 0.0 33.8 26.0 10.0 5 1 Female Right 100 1.4-0.2 2 4.3 5.4-4.8-9.9 6 2 Male Left 0-1.4-3.3 4.7-5.4 8.8 12.2 9.6 7 2 Male Left 25 7.8 6.1 9.2-7.6 48.7 17.6 0.0 8 2 Male Right 50 0-0.6 2.3 7.6 21.2 26.8 21.6 9 2 Male Right 50 2.3 0.5 2.6 8.9 30.2 31.1 19.3 10 2 Female Left 60-0.7-3.2 5 6.3 20.5 31.0 16.6 11 2 Male Left 65 3.7 0.9 5.5 3.3 11.8 15.0 15.0 12 2 Male Left 70 1.7-2.6 9.4 0.0 15.5 29.2 13.3 13 2 Male Right 75 1 0.3 0.5 5.3-11.9-16.7-22.7 14 3 Male Right 40 4.7 1.9 2.6 5.9 19.3 7.4 12.5 15 3 Male Right 15-1.5-1.6 3.5 2.0 0.2 2.3-7.7 16 3 Male Left 40 1 0.4 3.7 5.1 12.9 12.4 11.4 17 3 Female Right 50 2.1-1.4 5.6 3.8 18.0 15.6 5.1 18 3 Female Right 55 0 1.3 2 8.5 9. 12.2-5.7 19 3 Female Right 80 2.2-0.7 2.7 9.0 10.8 7.1 2.7 20 3 Male Right 80 6 3.7 3.5 8.2 23.4 4.9 3.8 21 3 Male Right 95 4.7 1.2 10.3 8.7 40.3 27.8 21.6 22 4 Male Left 65 4.1 0.9 6.5 10.1 17.2 12.2 9.9 23 5 Male Left 25 2.3 2 2-4.1 3.6-5.3-6.0 24 5 Male Right 35 0 0.7 7.8 12.3 24.7 16.8 3.4 25 5 Male Right 50 0 0.2 4.9 7.7 16.5 13.7-4.0 26 5 Female Right 110 0.8 1.2 1.4 14.7 5.7 10.8-1.7 27 6 Male Left 40 1-2.1 4.2 18.8 1.5 12.8 9.7 28 6 Female Left 45 1.7 1.3 1.5 0.0 12.1 16.3 17.1 29 6 Male Right 50 4.1 0.7 5.8-9.9 29.9 8.9-5.7 30 6 Male Right 60 0.6 0 7.2 22.0 11.0 21.6-0.9 31 6 Male Left 75 0.8-0.4 6.4 7.5 11.7 15.4 7.6 32 7 Male Right 35 1 1.4 2.9 15.7 3.9 14.2 8.2 33 8 Male Right 40 1.1 3.9 8.2 28.4 25.3 23.5-9.0 34 8 Male Left 45 6.4 3 4.4-3.8 16.4 27.0 21.6 35 8 Male Right 50 3 0.2 9.8 15.0 5.6 5.0-3.9 36 9 Male Left 30 11 8.2 7 8.7 32.3 4.3 3.7 37 10 Male Left 60 7.4 5.7 5.1 11.1 16.7 0.7-7.0 38 10 Female Right 15 3.5 3.3 0.8 8.4 11.8 9.0 3.0 39 10 Male Right 20 2.6 1.8 7.5 9.2 18.4 12.1-9.3 40 10 Male Left 50 5.1 3.8 7.2 5.2 5.7-1.6-2.2 41 11 Male Left 60 4.9 0.4 7.7-4.4 5.2 2.4 13.9 42 12 Female Right 50 1.2 1.2 6.2 14.6 24.5 21.6 4.6 43 12 Male Left 65 1 0.1 5.2 13.2 11.5 12.7-2.1 44 13 Male Right 50 1.7 0.1 9.4 10.5 1.9 2.0-12.3 45 14 Male Right 30 5.1 0 7 7.6 11.6 3.2 6.0 46 14 Male Right 50 4.6 1.9 6 31.6 10.4 4.3-5.6 47 18 Male Left 0 4.8 2.4 6.9 5.7 13.6 23.3 14.2 48 18 Male Right 30 2.3 3.1 5.6 15.3 4.3 3.3 7.9

27 전체환자를 4개군으로나누어제1군은나이가 5세미만이고좌우경부운동범위의차가 50 o 미만인환자 7명, 제2군은나이가 5세이상이고좌우경부운동범위의차가 50 o 미만인환자 13명, 제3군은나이가 5세미만이고좌우경부운동범위의차가 50 o 이상인환자 15명, 제4군은나이가 5세이상이고좌우경부운동범위의차가 50 o 이상인환자 13명으로정의하여이들간의비교를 ANOVA를사용해시행하였으며역시 p값이 0.05 미만인경우를통계적유의수준으로하였다. Fig. 1. The cephalometry was taken in the posteroanterior projection with the skull stabilized with a device that had references of the external auditory meatus for standardization. 결과관상면상에서두개부는안면부에대해환측으로만곡변형이있었다. 두개안면경사각은환측으로 5.2 o ±2.8 o 기울어져있었다. 두개골기저부경사각은환측으로평균 2.6 o ±2.6 o 기울었으며하악경사각은환측으로평균 1.0 o ±2.3 o 기울어져있었다. 측두골추체부상연에서부터측정한유양돌기의양측길이차이는 7.0%±8.5% 로대부분환측이반대측에비해길었지만환측이더작은경우도 7예있었다. 이 7예중 5예는좌우경부운동범위의차이가 50 o 미만이었다. 두개및안면부비대칭소견도확인되었다. 두개비대칭 (calvarial asymmetry from A B C D E Fig. 2. Parameters evaluating the craniofacial asymmetry using cephalometry. (A) The angle between the horizontal meatus line (line connecting bilateral external auditory meatus) and the horizontal petrous line (line connecting the bilateral upper margin of the petrous part of the temporal bone) was defined as the skullbase tilting angle (arrow) and the angle between the horizontal meatus line and the horizontal mandibular line (line connecting bilateral mandibualr angle) was defined as the mandibular tilting angle (arrow head). (B) The angle between the vertical cranial line(line connecting the sagittal suture and the nasal septum) and the vertical facial line(line connecting the nasal septum and the midline of two incisors of the mandible) was defined as the craniofacial tilting angle (arrow). (C) The length of the mastoid process was measured from the upper margin of the petrous part of the temporal bone to the mastoid process tip. The mastoid length difference ratio was calculated; the mastoid length of the normal side was subtracted from that of the involved side and then divided by the length of the normal side. The result is expressed as a percentage parameter. (D) The horizontal length of the skull was measured from a line passing the nasal septum, which is tangential to the horizontal meatus line to the margin of the parietal bone. The difference in the cranial asymmetry length was calculated by subtracting the length of the normal side from that of the involved side and divided by the length of the normal side. The result is expressed as a percentage parameter. (E) The horizontal lengths of the skullbase and mandibular angle were measured from the vertical facial line to the margin of the petrous part of the temporal bone and to the mandibular angle respectively. The skullbase asymmetry and the mandibular asymmetry were calculated by subtracting the length of the involved side from that of normal the side and then divided it by the length of the normal side. The result are expressed as percentage parameters. PB, petrous part of the parietal bone; EAM, External auditory meatus; MA, Mandibular angle; NS, Nasal septum; MI, midline of two central incisor; MP, Mastoid process.

28 Table 2. Case Analysis according to Age Mastoid Skullbase Mandibular Craniofacial process tilting tilting tilting length angle angle angle difference (degree) (degree) (degree) from skullbase (%) Calvarial asymmetry Skullbase Mandibular from asymmetry asymmetry vertical (%) (%) midline (%) Age 5 2.2±2.6* 0.1±2.2 4.6±3.1 4.0±5.3 18.2±13.9* 14.6±12.4 7.7±11.7 Age 5 3.0±2.6 1.7±2.1 5.7±2.4 10.0±10.0 12.9±8.7 10.7±8.6 2.0±8.8 p-value 0.271 0.017 0.158 0.007 0.114 0.203 0.060 *average±sd. Table 3. Case Analysis according to Difference in Neck Motion Mastoid Skullbase Mandibular Craniofacial process tilting tilting tilting length angle angle angle difference (degree) (degree) (degree) from skullbase (%) Calvarial asymmetry Skullbase Mandibular from asymmetry asymmetry vertical (%) (%) midline (%) Difference of neck motion 50 o 2.7±3.2* 1.5±2.8 4.8±3.0 5.8±9.4 14.9±11.8 11.8±8.2 5.7±9.0 Difference of neck motion 50 o 2.6±2.2 0.6±1.8 5.4±2.6 8.0±8.0 15.7±12.0 13.0±12.0 3.8±12.0 p-value 0.906 0.178 0.448 0.390 0.834 0.705 0.530 *average±sd. vertical midline) 은환측이 15.4%±11.6% 더컸다. 두개골기저부비대칭은 9.8%±9.1% 으로환측두개골기저부가더크게나타났고하악비대칭도 1.9%±9.5% 로환측이반대측에비해더큰경우가 31예였다. 5세미만인 22명과 5세이상인 26명사이에는하악경사각 (p= 0.017) 및유양돌기의길이차이 (p=0.007) 가나이가많은군에서더큰값을나타내었고이는통계적으로유의하였다. 두개안면부의만곡변형을나타내는지표인두개안면경사각은나이가많은군에서더큰값을나타내고두개안면부의비대칭을나타내는지표인두개비대칭, 두개골기저부비대칭및하악비대칭은나이가많은군에서더작은값을나타냈으나통계적으로유의한차이는아니었다 (Table 2). 또한, 양측경부운동범위의차이가 50 o 미만인군과 50 o 이상인군간에는하악경사각이운동범위차이가더큰군에서작게나타났고두개안면경사각및유양돌기길이차이등이경부운동범위차이가큰군에서크게나타났으나통계적으로유의한차이는없었다 (Table 3). 나이 5세기준및좌우경부운동범위의차이 50 o 을기준으로하여전체환자를 4개군으로나 Table 4. Analytic Results between the 4 Groups using ANOVA p-value Skullbase tilting angle (degree) 0.544 Mandibular tilting angle (degree) 0.066 Craniofacial tilting angle (degree) 0.337 Mastoid process length difference from skullbase (%) 0.015 Calvaridal asymmetry from vertical midline (%) 0.439 Skullbase asymmetry (%) 0.311 Mandibular asymmetry (%) 0.086 The results were analyzed by dividing the patients into four groups according to age and the difference in neck ROM. The mean values between 4 groups were compared. 눌경우 (Table 4) 유양돌기의길이만이 p=0.015로군간의차이가유의함을나타냈으며군간비교에서제1군이나머지군과유의한차이를보였다 (Fig. 3). 나머지측정값에서는통계적으로유의한차이는없는것으로나타났다. 각각의측정지표는관찰자내신뢰성, 관찰자간신뢰성을측정한결과모든지표에서 kappa 수치가 0.70 이상으로재현성 (reproducibility) 이높음을확인하였다.

29 Ratio to unaffected side (%) 14 12 10 8 6 4 2 0-2 -4 Mastoid process length difference Group I Group II Group III Group IV Fig. 3. Difference in the length of the mastoid process length between the 4 groups. The results were analyzed by dividing the patients into four groups according to age and the difference in neck motion. 고찰흉쇄유돌근의구축으로인한선천성근성사경을진단하기위해서는자세한병력청취와이학적검사, 방사선검사를통해사경을유발할수있는사시등의다른질환을감별하여야만한다. 선천성근성사경은생후 1세이전에는경과관찰만으로도호전되는경우가있으므로보존적치료가추천되고수술적치료의적절한시기와수술적응증에대해서는저자들에따라차이가있다 4). Ling 과 Low 12) 는 1세에서 4세사이를수술적치료의이상적인시기라고하였고 Canale 등 1) 과 Ippolito 등 8) 은 6세까지도수술적치료로좋은결과를얻을수있다고보고하였다. Shim 등 15) 은 8세이상의환자들을대상으로수술적치료를시행하여성장이완료된환자에서도목운동범위와두부경사도의호전과기능, 미용상만족스러운결과를얻을수있다고보고하였다. 두개안면비대칭은적절한시기에선천성근성사경이진단되어치료가이루어진다면진행을막을수있는것으로알려져있으나, 이미형성된두개안면비대칭에대한수술적치료의효과에대해서는논란이있어, 연령이나수술적방법에관계없이그결과가만족스럽지못하다는보고 1,9,16) 와연령이어린경우에는교정이된다는보고 2-4) 가있었다. 그러나현재두개안면비대칭을평가하는방법으로는육안으로두부와안면부의비대칭정도를평가하는방법이주로사용되고있으며비대칭정도를객관적으로정량화하는적절한방법이없어수술전후의변화를계측하는데어려움이있는상태이다. 두개안면비대칭을객관적으로평가하기위하여여러가지방법들이제시되었는데 Yu 등 17) 은 14명의치료받지않은선천성근성사경환자를대상으로 3차원컴퓨터단층촬영 (3 Dimensional CT, 3D-CT) 을이용한두개안면부분석에서환측안면부에저성장 (hypoplasia) 소견이있다고보고하였으며 Kim 등 9) 은얼굴받침대를이용한실물사진을이용하여비대칭각을측정하였고, 두부방사선촬영을이용하여두개수직각 (craniovertical angle) 및안와-두개수평각 (orbital plane-cranial horizontal line angle) 을측정하여두개안면비대칭을기술하였다. 본연구에서는양측외이도를잇는선을수평선으로하고두개골을고정한상태에서두개골을후전면으로단순방사선촬영하여두부회전으로인한영향을배제한상태로 13) 경사각 ( 두개골기저부, 하악, 두개안면 ) 과비대칭 ( 두개, 두개골기저부, 하악 ) 을계측하였으며유양돌기의크기를비교하였다. 본연구의결과중두개안면경사각 (craniofacial tilting angle) 이환측으로 5.2 o ±2.8 o 기울어져있는사실을통해체간과경부에서의변형외에안면과두개골사이에서도장축이환측으로기울어져있음을확인하였다. 또한두개의비대칭이있어환측의두개부가커져있었다. 선천성근성사경에서아이를눕혀서재우는경우후두골부위가지속적으로눌리어두개골의변형이오고엎드려재우는경우안면부와이마에변형이오는것으로알려져있으나두개안면부의만곡변형은그런외부적요인외에도환측흉쇄유돌근자체의구축및지속적인견인에의한요인도원인의하나로작용하고있을것으로생각된다 9). 양측의유양돌기의크기를비교하였을때환측의유양돌기가반대측에비해길어져있었고이는흉쇄유돌근의지속적인구축및견인으로인한이차적변화인것으로추정할수있다. 이에대해 Hollier 등 6) 은 16명의선천성근성사경환자를대상으로한연구중가장나이가많았던환자 1명에대한기술에서환측유양돌기가반대측에비해커져있다는사실을보고하였고 Kim 등 9) 도 3차원컴퓨터단층촬영검사상환측유양돌기가커져있는것으로확인된증례를제시한바있다. 본연구에서는 48명의환자를대상으로하여환측의유양돌기가반대측에비해평균 7.0%±8.5% 커져있음을확인하였다. 9예에서는 5% 이내의차이를보였고 18예에서는 5% 이상및 10%

30 미만의차이를보였으며 14예에서는환측이반대측보다 10% 이상길었다. 나이및경부운동범위등의인자가두개안면비대칭과관련이있는지를파악하기위해시행한분석에서는관상면상에서두개안면부의만곡변형을볼수있는지표인하악경사각이나이가많은군에서더큰값을나타내었고유양돌기의길이차이도나이가많은군에서환측과반대측과의길이차이가더컸다. 이는성장함에따라관상면상에서의만곡변형및유양돌기의길이차이가진행하는것으로볼수도있을것이다. 나이및경부운동범위 2개의기준을적용하여 4개의군으로나누어시행한분석에서는나이가작고좌우경부운동범위차이가작은군에서유양돌기길이차이가작게나타났다. 이는나이가작고경부운동범위제한이심하지않을때에는유양돌기길이차이가크지않으나, 나이가많고흉쇄유돌근의단축이심해경부운동범위제한이큰경우지속적인견인의효과로유양돌기길이의차가커지는것을의미한다고할수있다. 결론표준화된두부방사선계측촬영은선천성근성사경환자에서동반된두개안면비대칭을객관적으로정량화할수있는검사방법이다. 이러한계측을통해선천성근성사경환자에관상면상경추부에서의만곡변형뿐아니라두개안면부의만곡변형과두개골의비대칭이있다는것을확인하였다. 수술후두부방사선계측촬영을추시하여본연구에서제시한측정법으로분석한다면두개안면비대칭이수술후자연교정되는지여부를객관적으로확인할수있을것으로기대된다. 참고문헌

31 = 국문초록 = 목적 : 대상및방법 : 결과 : 결론 : 색인단어 :