ORIGINAL ARTICLE ISSN 1598-1703 (Print) ISSN 2287-6782 (Online) Korean J Endocr Surg 2015;15:34-40 http://dx.doi.org/10.16956/kaes.2015.15.2.34 The Korean Journal of Endocrine Surgery 부갑상선점수가갑상선전절제술후저칼슘혈증을예측할수있을까? 경북대학교의학전문대학원외과학교실박진희ㆍ박호용ㆍ정진향ㆍ황승욱ㆍ이지연ㆍ권택주ㆍ김완욱 Can Parathyroid Score Expect Hypocalcemia after Total Thyroidectomy? Purpose: The aims of this study were to investigate whether parathyroid score can predict hypocalcemia after total thyroidectomy with central lymph node dissection (CLND) and to determine clinical value of parathyroid score for treatment of hypocalcemia. Methods: A prospective review of 209 patients who underwent total thyroidectomy with CLND for papillary thyroid cancer from January to December 2012 was conducted. Parathyroid score was designed based on the number and color of parathyroid preservation (Save and intact color of a parathyroid was 2; Save but mild discoloration was 1.5; Not identification was 1.2; Autotransplantation was 1.0; Sacrifice was -1). Results: The mean numbers of parathyroid glands were as follows: save & intact color was 2.0; save & mild discoloration was 0.8; not identification was 0.8; autotransplantation was 0.4. The average parathyroid score was 6.54±0.69 (range 3.4 8.0). The average PTH was 16.3 at the 1 st POD. Transient and permanent hypocalcemia were 33.4% (70/209) and 0.9% (2/209), respectively. Parathyroid score was 6.78±0.54 in patients without transient hypocalcemia, 5.93±0.67 with hypocalcemia, parathyroid score was significantly lower in transient hypocalcemia, abnormal PTH at the 1 st POD (P<0.001, P<0.001). Conclusion: Parathyroid score may predict patients at risk of developing transient hypocalcemia after total thyroidectomy with CLND. Key Words: Hypocalcemia, Parathyroid hormone, Parathyroid score, Total thyroidectomy 중심단어 : 갑상선절제술, 부갑상선점수, 부갑상선호르몬, 저칼슘혈증 Jin Hee Park, Ho Yong Park, Jin Hyang Jung, Seung Ook Hwang, Jeeyeon Lee, Taek Ju Kwon, Wan Wook Kim Department of Surgery, School of Medicine, Kyungpook National University, Daegu, Korea Received March 16, 2015, Revised April 29, 2015, Accepted May 18, 2015 Correspondence: Wan Wook Kim Department of Surgery, School of Medicine, Kyungpook National University, 807 Hoguk-ro, Buk-gu, Daegu 702-120, Korea Tel: +82-53-200-2705 Fax: +82-53-200-2027 E-mail: kww1324@naver.com 서론 다양한갑상선수술의기법이발전되고있지만갑상선전절제술후의가장흔한합병증은부갑상선기능저하증으로일시적인저칼슘혈증의발생빈도는 0.3 49%, 영구적인저칼슘혈증은 0 13% 로보고되고있다.(1) 이러한술후저칼슘혈증은수술시직접적인부갑상선의손상또는의도하지않은제거, 부갑상선으로가는혈류차단, 혈종, 부갑상선박리후기절현상 (stunning), 칼시토닌 ( 부갑상선호르몬억제 ) 의분비또는혈액 의희석등이주된원인으로보고되고있으며, 그외에저칼슘혈증의위험인자로갑상선전절제술, 광범위한절제술, 악성종양, 림프절절제술, 흉골하갑상선선종, 그레이브스질병등이관여하는것으로알려져있다.(2-6) 대부분의경우, 저칼슘혈증은수술후약 2 3개월이지나부갑상선의기능이회복되면서정상화되는것으로알려져있으며, 영구적인부갑상선기능저하증은 0.5 5% 정도로드물게나타난다.(4,7) 부갑상선기능저하로인한저칼슘혈증은손발의저림, 입주변의감각이상, 심한경우손발근육, 안면근육의경련등을유발하여환자의재원기간을 Copyright 2015 Korean Association of Thyroid and Endocrine Surgeons; KATES. All Rights Reserved. cc 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.
박진희외 : Parathyroid Score after Total Thyroidectomy 35 늘리고환자의삶의질에나쁜영향을미치는중요한원인이되고있다.(8,9) 수술후저칼슘혈증을예방하기위해갑상선전절제술을받는모든환자에게관례적으로칼슘제를투여함으로써저칼슘혈증을예방할수있다고보도한바있다.(6,8) 하지만모든환자에게칼슘제를투여할경우치료가필요하지않는대부분의환자에게불필요한치료를하게되고칼슘제투여에따른부작용을경험할수있다. 그리고최근들어갑상선수술을전문으로하는숙련된외과의에의한갑상선절제술이시행되고, 부갑상선해부학에대한이해도가높아져부갑상선을보존하는갑상선술기발전으로인해부갑상선손상으로인한저칼슘혈증은과거보다많이줄어든양상이다. 이러한갑상선절제술후의저칼슘혈증을예측하기위한지표들로서수술후총칼슘수치, 이온화칼슘수치, 수술중또는수술후부갑상선호르몬 (parathyroid hormone, PTH) 수치등을이용한방법들이보고되고있으나정확도가높지않고검사를위해반복적인채혈로인한불편감이있었다.(6,10-13) 조기에저칼슘혈증을정확히예측할수록불필요한칼슘제투여를줄이고, 저칼슘혈증이있을경우빠른치료를할수있어저칼슘혈증증상의경험을예방하고빠른회복으로조기퇴원을할수있겠다. 본연구에서는지금까지보고된바없는부갑상선점수가갑상선전절제술후저칼슘혈증을예측할수있는지를전향적분석을통해살펴보고저칼슘혈증치료에있어서부갑상선점수의임상적유용성을알아보고자하였다. 방법 2012년 1월부터 12월까지칠곡경북대학교병원유방갑상선외과에서전통적인절개법으로갑상선전절제술및중심경부림프절절제술을시행받은 209명의갑상선유두암환자를대상으로하여전향적으로연구로진행하였다. 이기간중로봇수술을받은경우, 여포성또는양성종양으로수술한경우, 변형적경부 림프절곽청술 (modified radical neck dissection) 또는측경부의선택적림프절절제술 (selective neck dissection) 을시행받은경우와수술범위가일엽절제술로축소된경우, 중심경부림프절절제술을생략한경우는제외하였다. 그리고수술전골다공증등의이유로칼슘제를복용하였거나부갑상선기능이상 ( 항진증, 저하증 ), 만성신부전증, 요로결석, 이전에경부수술을받은과거력, 경부방사선치료과거력, 입원전 7일이내에아스피린또는혈액응고억제제의복용력이있는환자도본연구에서제외하였다. 모든수술은동일한갑상선외과전문의 1명 ( 김완욱 ) 에의해시행되었고수술은 Ultrasonic activated shears (Harmonic Focus R, Ethicon Endo-Surgery, Inc, Seoul, Korea) 또는 LigaSure Small Jaw R (Covidien, Energy-based Devices, Boulder, Colorado, USA) 를사용하여시행하였다. 에너지를이용한수술시주변구조물의열손상을막기위해반회후두신경으로부터최소 3 mm, 부갑상선으로부터 2 mm 이상의안전거리를두고기구를작동하였다. 모든부갑상선점수는수술중집도의에의해평가되었다. 부갑상선점수는술중부갑상선의확인및보존여부, 보존된부갑상선의색깔, 부갑상선의자가이식을근거로산출하였는데부갑상선이보존되고온전한색깔일경우 2점, 보존되었지만약간변색이있을경우 1.5점, 확인하지못한경우 1.2점, 자가이식 (Autotransplantation) 한경우 1점, 확인했으나암의침윤등으로살리지못하고절제한경우는 1점으로점수화했다 (Fig. 1). 부갑상선을보존하였으나약간변색이있는경우는수술종료시점까지관찰하여더이상의변색이없을경우자가이식없이수술을마쳤다. 갑상선절제술및림프절절제술후에조직내에함께적출된부갑상선이있는지찾도록노력하였으며부갑상선을제자리에살리지못하고예기치않게함께절제된경우또는살렸으나혈류장애등으로변색이심한경우에는괴사가능성이높으므로부갑상선을적출하여 1 mm 이하로작게절편하여반대측흉쇄유돌근 (sternocleidomastoid muscle) 에자가이식하였다. Fig. 1. Gross status of parathyroid gland according to color of it. Surgeon saved parathyroid with intact color (A); parathyroid could be save and it became mild discolored (B); parathyroid could be saved but it became severe discolored (C).
36 Korean J Endocr Surg 2015;15:34-40 journal.kates.or.kr 수술후혈중 PTH, 총칼슘및이온화칼슘, 인수치등을측정하였는데이중혈중총칼슘, 이온화칼슘및인수치는수술직후, 수술후 1일, 2일, 10일 ( 첫외래방문시기 ), 2개월및 6개월에측정했으며, PTH 수치는수술후 1일, 10일, 2개월및 6개월에측정하였다. 환자는갑상선수술후저칼슘혈증의증상으로양측손발의저린감및감각이상, 입주위의감각이상, 근육경련, 강직, Trousseau s sign, Chvostek s sign 등이나타나는지를확인하였다. 재원기간중 1회라도저칼슘혈증의증상이나타나거나재원기간중혈중총칼슘수치 ( 범위 : 8.6 10.2 mg/dl) 가 8.0 mg/dl 미만또는이온화칼슘수치 ( 범위 : 1.13 1.32 mmol/l) 가 1.0 mmol/l 미만으로떨어지면저칼슘혈증으로분류하여칼슘제투여를하였고, 술후 1일째 PTH 수치가 5 pg/ml ( 범위 : 14 72 pg/ml) 미만인경우에는증상이없고칼슘이정상이어도수술후 2일째부터칼슘이떨어지는임상적경험을바탕으로저칼슘혈증증상의경험을막기위해예방적으로칼슘제를미리투여하였다. 치료가필요한저칼슘혈증에는 calcium carbonate (500 mg 3 T 3번 / 하루, Carnit R, Jinyang Pharm co., Seoul, Korea), calcitriol (0.25 μg 1 C 2번 / 하루, Bonky R, Yu Yu Pharmaceutical Co., Seoul, Korea) 을복용하도록하였다. 정맥내칼슘주사는중증의저칼슘증상 (Trousseau s sign 양성, tetany, carpopedal spasm) 이있거나총칼슘 <6.0 mg/dl 또는이온화칼슘 <0.8 mmol/l 인경우에시행하였다. 술후 6개월후 PTH가정상이하 (<14 pg/ml) 시영구적저칼슘혈증으로분류했다. 수술후 2일째출혈및장액종소견이없으며저칼슘혈증증상이없고총칼슘 >8.0 mg/dl, 이온화칼슘 >1.0 mmol/l이고배액량이 30 cc/ 일이하인경우에배액관을제거후퇴원하도록하였다. 통계처리는 SPSS Version 22 (SPSS Inc., Chicago, IL, USA) 을사용하였고연속형변수는 independent t-test 또는 Mann-Whitney test를범주형변수는 Chi-square test 또는 Fisher s exact test로검증하였고부갑상선점수의유용성과절단값 (cut-off value) 을판단하기위해 Receiver Operating Characteristic (ROC) curve를이용하였고 P <0.05 인경우를통계적으로유의하게간주하였다. 결과 환자의임상병리학적특성은 Table 1에서보여지고있다. 총 209예중남자와여자의비율은 1:5.9였고, 평균연령은 49.3 세 ( 범위 : 15 77세 ) 였다. 평균수술시간은 103.4±19.9분 ( 범위 : 68 230분 ) 이었으며평균재원기간은 3.3±0.1일이었다. 갑상선암의평균크기는 0.9±0.1 cm ( 범위 : 0.11 6.5 cm) 였다. 절제된중심경부림프절개수는평균 9.5±0.4개 ( 범위 : 1 31개 ) 이며그중이후병리조직검사상림프절전이로확인된경우는평균 1.3±0.1개 ( 범위 : 0 12개 ) 였다. TNM 병기상 I, II, III가각각 114예, 2예, 92예있었다. 수술후합병증으로일시적인반회후두신경마비가 6예 (2.8%), 영구적인마비가 2예 (0.9%) 있었다. 일시적저칼슘혈증은 70예 (33.4%) 에서있었지만대부분 2달이내에회복되었고 6 개월이상지속되는영구적저칼슘혈증은 2예 (0.9%) 에서있었다. 수술후출혈및장액종이각각 1예씩있었다. 수술후총칼슘및이온화칼슘수치의변화는다음과같다 (Fig. 2). 수술후 1 2 일째최저점으로떨어졌다가상승하기시작하여수술후 10일이후로거의정상으로회복되었다. 수술후 1일째 PTH 평균값은 16.3±15.1 pg/ml ( 범위 : 0 85.7 pg/ml) 고정상범위이하로떨어진경우는 88예 (42.1%) 에서있었다. PTH 수치도칼슘과비슷하게수술후 10일째지나면서회복이되기시작하였고수술 10일째평균 21.6±18.8 pg/ml ( 범위 : 0 84.9 pg/ml) 였고, 정상범위이하로떨어진경우는 63예 (30.3%) 다. 부갑상선점수에따른부갑상선의평균개수및합산은다음과같다 (Table 2). 수술건수당평균적으로부갑상선을보존하고온전한색깔을지닌것이 1.95개, 보존하였지만약간변색이있는것이 0.85개, 확인안된것이 0.78개, 자가이식한것이 0.39개였다. 술중부갑상선의확인및보존여부, 보존된부갑상선의색깔, 부갑상선의자가이식에따라술자의판단에따른가중도를근거로산출한부갑상선점수의평균은 6.54±0.69 ( 범위 : 3.4 8.0) 이었다. 일시적저칼슘혈증이없던환자에서부갑상선점수는 6.78±0.54였고저칼슘혈증이있던환자에서는 5.93±0.67이었으며통계적으로의미있는차이를보였다 (P <0.001) (Table 3). 또한수술후 1일와 10일째 PTH 수치가정 Table 1. Clinicopathologic characteristics of patients Age (years) 45 <45 Characteristics Total (n=208) (range or %) 49.3±0.8 (15 77) 126 (60.6%) 82 (39.4%) Gender (male:female) 1:5.9 Tumor size (cm) <1 cm Multiple tumor Hashimoto s thyroiditis 0.9±0.1 (0.1 6.5) 138 (66.3%) 89 (42.8%) 45 (21.6%) Extrathyroidal extension Central lymph node metastasis 123 (59.8%) 85 (40.9%) Number of retrieved lymph node (n) 9.5±0.4 (1 31) Number of metastatic lymph node (n) 1.3±0.1 (0 12) Operation time (min) 103.4±1.3 (68 230) Hospital stay (day) 3.3±0.1 (2 7) Total drain amount (ml) 114.5±5.1
박진희외 : Parathyroid Score after Total Thyroidectomy 37 Fig. 2. Changes of Serum total calcium (A) and ionized calcium (B) level according to postoperative day. Serum total calcium and ionized calcium level were decreased at postoperative #1, 2 days and recovered after postoperative #10 days. Table 2. Parathyroid score based on the preservation and color of parathyroid, mean number of parathyroid Gross status of parathyroid Parathyroid score Mean number of parathyroid Sum of parathyroid score Preservation of parathyroid with 2 1.95 3.90 intact color Preservation of parathyroid with 1.5 0.85 1.27 mild discoloration Non-identification of parathyroid 1.2 0.78 0.93 Autotransplantation of parathyroid 1 0.39 0.39 Sacrifice of parathyroid 1 0.02 0.02 Sum 4.00 6.54 Table 3. Comparison parathyroid score according to PTH level, hypocalcemia Characteristics PTH at POD #1 Normal Abnormal PTH at POD #10 Normal Abnormal Hypocalcemia No Transient Permanent Sum of parathyroid score 6.8±0.5 6.0±0.6 6.7±0.6 6.3±0.6 6.8±0.5 5.9±0.6 6.1±0.11 P value <0.001 <0.001 <0.001 0.305 PTH = parathyroid hormone; POD = postoperative day. 상수치보다낮았던환자에서도부갑상선점수가의미있게낮았다 (P<0.001, P<0.001). 하지만, 영구적저칼슘혈증이없던환자에서부갑상선점수는 6.55±0.70, 있던환자에서는 6.13±0.11이었으나통계적인차이를보이지않았다 (P=0.305). 일시적인저칼슘혈증을상태변수로하고부갑상선점수를검정변수로 ROC curve를산출하였을때영역범위 (area under the Fig. 3. ROC (Receiver Operating Characteristic) curve and AUC (Area under the curve) of parathyroid score for transient hypocalcemia. curve, AUC) 는 0.870 였고점근유의수준은 0.000, 95% 신뢰구간은하한 0.808, 상한 0.923이었다 (Fig. 3). 절단값 (cut-off value) 수치를 6.3으로하였을때이에따른민감도, 특이도는 82.6%, 83.1% 였다.
38 Korean J Endocr Surg 2015;15:34-40 journal.kates.or.kr 고찰 과거에비해외과의사의기술기법의발전과수술도구의개발로갑상선수술이안전하게시행되고있지만저칼슘혈증은갑상선수술후의가장흔한합병증중의하나이다. 수술후저칼슘혈증의위험인자로는그레이브스병, 갑상선의크기, 갑상선염, 광범위한림프절절제술, 진행된병기, 나이, 여성, 수술전총칼슘수치및혈중비타민D 수치등이있다고알려져있다.(3,4,14) 그리고저칼슘혈증의원인으로는수술중부갑상선손상, 술중공급되는수액에의한비특이적혈액희석, 술후비타민D 대사의변화, Endothelin 1의분비에의한 PTH의분비저하, 장시간의수술로인한체온의저하등이있다.(5) 이런원인들가운데수술중부갑상선손상에의한경우가대부분이다. 이는부갑상선의위치변이가많아수술중찾기가어려울수있어부갑상선의보존이쉽지않고그뿐만아니라부갑상선의혈관을보존하지못하는데에따른혈류장애도중요한원인이된다. 부갑상선은일반적으로좌우각각 1쌍으로총 4개의상, 하부갑상선이존재하나 2개에서 9개까지보고된바도있다. 상부갑상선의위치는보통갑상선의후외방에존재하나, 설골하부에서부터상부종격동까지어디든지위치할수있으며, 약 7% 내외에서는갑상선내에존재할수도있다.(15) 상부갑상선은일반적으로갑상선의후면부위위치하고하갑상선동맥과반회후두신경이교차하는점에서상방 2 cm 이내에위치하게되며주위지방조직에쌓여있는경우가많다. 하부갑상선은좀더위치변이가심한데주로갑상선의하부나갑상선흉선인대근처에있는경우가가장많고흉선안에위치하고있는경우도드물지않게있다. 일반적인경우상부갑상선은반회후두신경후방에, 하부갑상선은신경전방에주로위치한다.(16,17) 부갑상선을잘살리기위해서는먼저부갑상선을잘찾고림프절, 지방과구분할수있어야한다. 부갑상선은색깔, 모양으로지방, 림프절과구분하는데부갑상선은지방보다좀더어둡거나짙은노랑색이고림프절보다부드럽고후물거리는양상을하고있다. 부갑상선은갑상선피막에쌓여있는경우가종종있고부갑상선으로가는혈관을잘살리기위해위에서섬세한피막박리 (capsular dissection) 를통한부갑상선혈류보존이필수적이다. 혈류보전을위해서는부갑상선으로가는혈관들을잘확인하고혈관을근위부에서결찰하지않고갑상선에가깝게원위부에서결찰하여부갑상선으로가는혈관을보존하도록한다. 특히상부갑상선의경우상 / 하갑상동맥의분지에서혈류를공급받지만, 하부갑상선은하갑상동맥의분지에서만혈류를공급받기때문에하갑상동맥의보존이특히중요하다. 그리고부갑상선주변에지방조직과함께살리면좀더좋은결과를얻을수있 고흉선내부갑상선이위치해있을수있으므로흉선은제거하지않도록한다. 갑상선발생의변이를생각하여갑상선내에부갑상선이존재할가능성도염두에두도록한다.(15) 만약, 의도하지않게부갑상선이함께제거되었거나혈류장애로부갑상선의변색이있는경우는부갑상선을적출해서절편하여흉쇄유돌근이나요골근에반드시자가이식을하는것이장기적으로부갑상선기능저하를예방하는데도움이된다.(15,18,19) 그러므로갑상선절제및림프절절제술후조직과함께제거된부갑상선이있는지찾아보는것이중요하다. Thomusch 등 (20) 은저칼슘혈증을예방하기위해적어도 2개이상의부갑상선이기능적으로보존되어야하며 3개이상보존은큰이득이없다고보고했으며다른연구에서는적어도 3개이상의부갑상선이보존되어야한다고보고된적있다.(21,22) 반면, 적어도 1개이상의부갑상선이보존되면영구적저칼슘혈증을일어나지않는다는연구결과도있다.(23) 또한부갑상선자가이식만으로는장기적으로관찰하였을때 43% 까지만회복되기때문에가능한잘보존하도록노력해야한다는보고도있으며변색된부갑상선의기능은일시적으로손상된것이며술후짧은시간내에회복된다는보고도있다.(24,25) 수술후저칼슘혈증이생길가능성을대비하여술후 PTH, 총칼슘, 이온화한칼슘수치및저칼슘혈증증상여부등의지속적인추적관찰이필요하며, 술후최소 2일이상자세한추적관찰을시행하여야한다. Kim 등 (26) 은또한혈중이온화칼슘수치는술후 2일째가장낮게나타나기때문에이때까지주의를기울여야함을보고하였다. 하지만이는환자들에게매일채혈을해야하는경우환자에게불편감및경제적인부담을줄수있다. 일부논문에서는모든환자들에게동일한칼슘제제를투여함으로써퇴원을보다안전하고빠르게할수있다고보고하였으나, 모든환자들에게칼슘제제를투여하는것은경제적으로도효과가없을뿐아니라환자들에게불필요하게투여함으로써칼슘제의부작용을경험하게할수있다.(27) 그러므로저칼슘혈증을정확하게예측하는것은치료가불필요한환자에게서칼슘제투여를막고증상이있을환자에게미리칼슘제를투여함으로써저칼슘혈증증상을최소화하고퇴원을빨리할수있도록도와주기때문에중요한문제라할수있겠다. 부갑상선기능저하증예측인자로수술중에 PTH 수치를측정하여 10 pg/ml 이하인경우에저칼슘혈증이발생할가능성이높으므로조기에비타민 D를투여하면저칼슘혈증의증상을줄이는데도움이된다는보고도있다.(28) 지금까지의연구에서는부갑상선의개수, 자가이식한부갑상선의점수가갑상선전절제술후저칼슘혈증과어떠한관련이있는지에대한보고들은있었지만본연구에서처럼부갑상선의개수, 변색, 자가이식, 확인수, 적출한수를점수화하여술후저칼슘혈증과의관련성을
박진희외 : Parathyroid Score after Total Thyroidectomy 39 연구한논문은없었다. 이에대해본저자는갑상선전절제술후발생하는저칼슘혈증을예측하기위한새로운접근으로수술중부갑상선의보존에대해육안적판단하여부갑상선점수를합산을하여이를술후저칼슘혈증발생을미리예측할수있는지를알아보고자했으며칼슘치료에도움이되는지, 그리고일시적저칼슘혈증치료를위한부갑상선점수의절단값 (cut off value) 를확인해보고자하였다. 부갑상선점수는술자의경험및참고문헌을참고로정하였는데, 변색없이부갑상선을잘보존한경우 2점, 부갑상선의약간의변색이있고더이상변색이진행되지않은경우일시적인기능저하증은있으나곧회복이되어어느정도기능을할것이므로 1.5점으로하였다. 부갑상선을확인하지못한경우의도적으로부갑상선을찾으려고더이상애쓰지않아서부갑상선위치의변이에의해어딘가에남겨져있을가능성이있고, 적은빈도이지만수술시조직과함께제거될가능성도있으므로 1.2점을주었고, 자기이식을한경우부갑상선은약 43% 정도기능을회복하고그기간까지최소 1주이상, 평균 3개월정도소요되므로 1점을주었다. 본연구에서는수술시평가한부갑상선점수를각각환자임상증상, 수술후이온화칼슘, 칼슘농도를근거로본연구에서정의한일시적인저칼슘혈증및술후 1일째 PTH 수치와연관관계를비교했으며모두유의한상관관계가있었다. 영구적인저칼슘혈증의빈도가 2예로적어서부갑상선점수로정확하게예측하기어려웠다. 절단값을높일수록민감도는낮아지고특이도는높아지게되는데적정한민감도, 특이도를위해서절단값을 6.3으로선택하였다. 본연구의결과를바탕으로부갑상선점수를임상치료에적용하기위해갑상선전절제술후칼슘치료에대한알고리즘을고안하였다. 수술후 PTH 수치가정상인경우에는저칼슘혈증이있는경우가거의없어더이상칼슘제치료는필요없을것으로생각하였다. PTH 수치가정상이하인경우 부갑상선점수를계산하여절단값인 6.3 초과인경우칼슘복용없이지켜보고이중저칼슘혈증증상이있는경우와부갑상선점수가 6.3 이하인경우에칼슘제복용을하도록하였다 (Fig. 4). 이와같이부갑상선점수를임상에적용할경우갑상선수술후필요한환자에게만칼슘제복용을하도록하여불필요한칼슘치료를줄이고, 필요한환자에게보다빨리적절한칼슘치료를하여수술후 1 2일째부터올수있는저칼슘혈증증상경험을줄이고늦게칼슘복용을시작할경우칼슘수치회복을위한재원기간이길어질수있는데빠른치료로재원기간을줄일수있고불필요한혈액검사를줄일수것으로사료된다. 부갑상선점수는술자의경험및노력에따라정확도, 민감도가달라질수있으므로 PTH 수치, 칼슘수치와절대적으로비교하여우월한지여부를알기어렵다. 그리고혈중 PTH와칼슘수치를대치할정도로민감하고정확하기는어려우나부갑상선점수를잘평가하면 PTH가약간떨어져있으나저칼슘혈증증상이없어칼슘복용을할지결정하기어려운환자들의치료전략에보조적으로사용할수있을것으로사료된다. 부갑상선점수에대한본연구에는몇가지제한점이있다. 첫째, 저자가정한부갑상선의보존상태에따른부갑상선점수는개인적인경험및논문에따른것이지만이에명확한근거가없어통계학적힘 (power) 를결정하기어렵다는점이다. 둘째, 집도의의경험의차이에따라부갑상선점수를매기는기준및정확도가차이가있을수있고주관적일수있다는것이다. 지방, 림프절을부갑상선으로잘못인식하거나부갑상선의혈류장애에따른변색에정도에따라점수가달라질수있다. 부갑상선점수가적은빈도수로생긴영구적부갑상선기능저하증이있는환자의평가에크게도움은되지않았다. 마지막으로부갑상선점수는전체개수를 4개를기준으로한점수체계이므로부갑상개수에변이가있을수있을경우 (5 20%) 점수에영향을줄수있다. 부갑상선점수를임상적으로잘적용하기위해서는집도의의많은경험과정확한평가를하기위한노력그리고향후많은환자를대상으로한추가연구가필요할것으로사료된다. 결론 Fig. 4. Algorism for calcium supplement based on parathyroid hormone (PTH) at postoperative (POD) #1 day and parathyroid score. 부갑상선보존및상태에근거한부갑상선점수는갑상선전절제술후일시적인저칼슘혈증및 PTH 수치와상관관계가높았다. 부갑상선점수는수술후일시적인저칼슘혈증이올수있는위험도가높은환자를미리예측하는데도움이되었으며갑상선수술후불필요한칼슘치료를줄이고저칼슘혈증으로칼슘치료가필요한환자에게보다빨리적절한칼슘치료를하는데도움이될것이다.
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