대한임상신경생리학회지 12(2):55~6, 21 ISSN 1229-6414 Original Article 수근관증후군에서임상양상척도및신경전기진단결과와정중신경초음파소견의상관관계 고려대학교의과대학재활의학교실 The Correlation between Ultrasonographic Findings of Median Nerve and Clinical Scale and Electrodiagnotic Data in Carpal Tunnel Syndrome Gyu Ho Lee, M.D., Sei Joo Kim, M.D., Joon Shik Yoon, M.D., Byung Kyu Park, M.D., Jung Mo Cho, M.D., Jin Seok Jung, M.D. Department of Physical Medicine and Rehabilitation, Korea University School of Medicine, Seoul, Korea Received 1 June 21; received in revised form 18 June 21; accepted 13 October 21. Background: The aim of this study is to identify the correlation between ultrasonographic findings of median nerve and clinical scale and electrophysiologic data in carpal tunnel syndrome. Methods: Forty three patients (79 hands) with electrophysiologically confirmed carpal tunnel syndrome were evaluated. Clinical symptoms were examined by Historical-Objective (Hi-Ob) scale. Electrophysiologic data and Padua scale were used for severity of electrophysiology. In ultrasonographic study, cross sectional area and flattening ratio of median nerve were measured at distal wrist crease level (DWC), 1cm proximal to distal wrist crease level, and 1cm distal to distal wrist crease level. The correlation between Hi-Ob scale, electrophysiologic data and ultrasonography was measured with Spearman rank test. Results: The mean Hi-Ob scale was 2.4. Mean Padua scale was 4.. In ultrasnonographic study, cross sectional area and flattening ratio were.112 cm 2 ±.25 and 3.±.6 at 1cm proximal to DWC level,.118±.26 cm 2 and 2.9±.4 at DWC level, and.17±.32 cm 2 and 3.±.4 at 1 cm distal to DWC level. Hi-Ob scale was not correlated with cross sectional area and flattening ratio of median nerve. Hi-Ob scale was correlated with Padua scale positively (r=.44) and correlated with amplitudes of CMAP and SNAP, negatively (r= -.33; r= -.3). Cross sectional area of median nerve was significantly correlated with Padua scale, amplitudes and latencies of CMAP and amplitudes of SNAP. Conclusions: Ultrasonographic findings of median nerve and electrodiagnostic data had statistically significant correlation. Consequently, ultrasonography could be an adjunctive method in diagnosis of carpal tunnel syndrome. Key Words: Carpal tunnel syndrome, Ultrasonography, Electrodiagnosis, Clinical Scale 서 론 Address for correspondence; Joon Shik Yoon, M.D. Department of Physical Medicine and Rehabilitation, Korea University Kuro Hospital, 97 Gurodong-gil, Guro-gu, Seoul 152-73, Korea Tel: +82-2-2626-15 Fax: +82-2-859-5422 E-mail: rehab46@korea.ac.kr 수근관증후군은포착성말초신경병증중가장흔한질환으로중년여성에호발하며정중신경이완관절부위에서포착되어수지의감각이상과근력약화및통증을일으키는질환이다. 1,2 수근관증후군은수부의통증, 저림및작열감등의증상과정중신경분포부위의감각손상, 무지 Copyright 21 by The Korean Society of Clinical Neurophysiology 55
구근위축, 증상유발검사의양성소견등의임상소견을특징으로한다. 그러나경추신경근압박증, 탈수초질환, 당뇨나독성말초신경병에서도비슷한증상및임상소견을보일수있으므로이들질환과의감별이필요하다. 3 수근관증후군의진단은대부분신경전기진단검사로이루어진다. 신경전기진단검사로서신경의손상부위와그정도를평가할수있지만신경자체나주변조직에대한공간적정보를제공하지못하며큰수초섬유의탈수초화나축삭손상이어느정도일어난후에야이상소견을보이고세섬유를평가하지못한다는단점이있다. 2,4,5 초음파는방사선조사없이말초신경의해부학적구조평가가가능하고신경전기진단검사에비해비침습적이고검사비용과시간을절약할수있는장점이있다. 특히수근관증후군이나주관증후군등의포착성신경병증진단에유용하며공간정보를통해검사와함께주사치료나시술이가능한이점이있어최근말초신경평가를위한초음파의사용이점차확대되고있다. 이전의연구들에서전기진단검사와임상소견은어느정도상관관계가있는것으로보고되었으나지속적인연구가부족하였다. 또한초음파와전기진단학적검사는강한상관관계를보이는것으로알려져있으나초음파와임상소견의상관관계에대한연구는활발히진행되지않았다. 1,2,6-9 이연구는수근관증후군에서정중신경의초음파소견과임상양상척도및신경전기진단결과의상관관계를확인하고자하였다. 대상과방법 1. 연구대상손저림이나통증작열감, 이상감각등의증상과정중신경분포부위의감각이상, 무지구근육의위축, Tinel 검사, Phalen 검사및 reverse Phalen 검사에양성반응을보이는환자에서신경전기진단검사를시행하였으며수근관증후군으로진단된환자 43명 (79수) 을대상으로연구를진행하였다. 완관절의수술이나골절병력, 임상소견이나전기진단에서근위부정중신경병증, 신경근병증, 다발성신경병증등, 또는통풍, 당뇨, 만성신부전, 류마티스관절염, 전신성홍반성낭창, 임신, 말단비대증, 비타민 B12, 엽산결핍증등수근관증후군과연관된질환및최근 2주이내소염진통제등을복용한환자는대상에서제외하였다. 모든제외기준은병력, 신경근골격계에대한이학적검사, 방사선, 전기진단및초음파소견등을이용하여확인하였다. 2. 연구방법환자의사전동의를받은후임상척도평가, 전기진단및전기생리학적평가 (Padua 척도 ), 그리고초음파의순으로시행하였다. 1) 임상척도 (Hi-Ob 척도 ) Hi-Ob 척도는환자의주관적증상과객관적임상소견을근거로단계 ~5까지로나뉘며 단계는정상을 5단계로갈수록수근관증후군의심한정도를나타내며다음과같이분류한다. 1 단계 : 수근관증후군의증상이라할만한것이전혀없음. 단계 1: 취침시에만이상감각이있음. 단계 2: 주간에잠깐이라도이상감각이있음. 단계 3: 정중신경영역손가락의감각저하가있음. 단계 4: 위약을동반하거나하지않은무지구위축위축 : 손의다른내재근과비교시상대적위약 : 저항을가한무지외전으로검사단계 5: 무지구의완전위축또는완전마비완전위축 : 손바닥과비교했을때무지구가오목한경우완전마비 : 손바닥에서부터배측으로무지외전을하지못하는경우 2) 전기진단검사및전기생리학적평가 (1) 전기진단검사모든환자에서정중신경과척골신경의운동-감각신경전도검사를시행하였다. 피부온도를섭씨 32~34 로유지하고직류전류자극기와표면전극을이용하여표준적인방법대로최대초과경피자극을시행하였다. 정중운동신경전도검사는단무지외전근의중앙에활성기록전극을부착한후근위부 7 cm에서자극하여기시잠복기와기저선에서정점까지의진폭을구하였다. 감각신경검사는역행성신경전도검사를하였으며정중감각신경의활성전극을제3 수지의근위지절에부착한후 14 cm 근위부손목과 7 cm 근위부손바닥을자극하여기시잠복기와기저선에서정점까지의진폭을측정하였다. 이와함께침근전도검사를시행하여신경근병증, 근육질환, 신경근접합부질환등을감별한후최종적으로수근관증후군을진단하였다. 11 56 Korean J Clin Neurophysiol / Volume 12 / December 21
수근관증후군에서임상양상척도및신경전기진단결과와정중신경초음파소견의상관관계 (2) 전기생리학적평가 (Padua 척도 ) 전기진단검사에서감각신경과운동신경의결과를함께고려하여 1~6단계로나누어지며 1단계는정상을, 6단계로갈수록심한손상을나타내며다음과같이분류한다. 12 단계 1: 모든검사에정상단계 2: 표준감각신경검사에정상이나분절검사또는비교검사에비정상단계 3: 감각신경전도속도의저하및운동신경원위부잠복기의정상범위단계 4: 감각신경전도속도의저하및운동신경원위부잠복기의지연단계 5: 감각신경활동전위소실및운동신경잠복기의지연단계 6: 감각신경및운동신경활동전위소실 1 cm 원위부및 1 cm 근위부 ( 전완의말단 ) 에서측정하였다 (Figure 1A). 단면적은초음파의지속적단면적추적방법을이용하여횡단면에서고음영의신경외피에서가장근접한저음영을 3회측정한후평균값으로구하였다 (Figure 1B). 편평비는정중신경횡단면의가장큰직경과가장작은직경의비로역시 3회측정한수치의평균값을구하였다 (Figure 1C). 4) 통계분석통계분석은 SPSS 12.을이용하였다. Hi-Ob 척도와신경전도검사소견중운동, 감각신경전위잠복기및진폭및 Padua 척도, 그리고초음파검사에서구한세부위의단면적과편평비등의상관관계를 Spearman rank test로각각평가하였으며 p값이.5보다낮을때통계적유의성이있는것으로결정하였다. 3) 초음파고해상초음파기계로 HDI 35 (Philips, Holland) 의 7~12 MHz 탐촉자를사용하여환자의전기진단, 임상척도결과를검사자가알지못한상태에서초음파를시행하였다. 탐촉자의각도는직각을유지하여각형성 (angulation) 시실제와다른저에코로보이는이상현상인비등방성 (anisotropy) 을방지하였다. 또한정중신경의변형을막기위해탐촉자로피부표면을압박할때주의하였고손목의자세에따라정중신경의모양이변할수있으므로손목을중립위치로유지하였다. 9 이전의연구에서는한부위에서만측정한경우가많았으나본연구에서는수근관의원위부와근위부를포함시켜세부위에서측정하였다. 환자의자세를앙와위로한후전완을회외시킨상태에서정중신경의단면적, 편평비 (flattening ratio) 를원위손목주름부위와이로부터 결과환자의평균연령은 53.4세였으며, 여성은 4명, 남성은 3명이었다. 평균 Hi-Ob 척도는 2.4±1.4였다. 정중운동신경의잠복기및진폭은각각평균 5.3±1.7 ms, 6.7±3.6 mv, 감각신경의잠복기및진폭은 4.3±1.1 ms, 17.9±11.1 uv였고, Padua 척도는평균 4.±1.7 단계이었다. 측정한정중신경의단면적과편평비는각각전완의말단에서.112±.25 cm², 3.±.6, 원위손목주름부위에서.118±.26 cm 2, 2.9±.4, 그리고손목주름원위부에서는.17±.32 cm 2, 3.±.4로원위손목주름에서단면적이가장컸고편평비는비교적일정하게나타났다 (Table 1). 전체 79수중 Padua 척도는 4단계가 48수로가장많았으며, Hi-Ob 척도는 4단계와 2단 A B C Figure 1. Ultrasonographic transverse scan at different three level. (A) level C: The cross sectional area and flattening ratio at the distal wrist crease, level B: 1 cm proximal to the level C, level D: 1cm distal to the level C. (B) Cross sectional area of median nerve (outlined) at distal wrist crease level; the cross sectional area.12 cm 2. (C) Flattening ratio: the ratio of the nerve's major to minor axis at three levels (2.15=.58 cm/.27 cm) P: pisiform, S: scaphoid. Korean J Clin Neurophysiol / Volume 12 / December, 21 57
Table 1. Ultrasonographic cross sectional area of carpal tunnel syndrome Cross sectional area (cm 2 ) Flattening ratio 1 cm proximal to DWC.112±.4 3.±.85 DWC.118±.3 2.9±.57 1 cm distal to DWC.17±.4 3.±.71 Values are mean±s.d. DWC, distal wrist crease. Padua Hi-Ob 6 5 48 3 25 25 26 4 2 cases 3 cases 15 14 2 14 1 6 4 5 2 1 2 3 4 5 6 Figure 2. Distribution of various Hi-Ob and Padua scales. 1 5 7 7 1 2 3 4 5 Table 2. Correlation between Hi-Ob scale and electrophysiologic data Padua scale Motor latency Motor amplitude Sensory latency Sensory amplitude Hi-Ob scale.44 *.2 -.33 *.13 -.3 * Values are Spearman s correlation coefficiency. Hi-Ob scale, historical-objective scale. * p<.5. 계가 26수와 25수로많았다 (Figure 2). Hi-Ob 척도단계가높을수록 Padua 척도단계도증가하는양의상관관계를보였고, Hi-Ob 척도가높을수록운동신경과감각신경의진폭이감소하여, 임상증상과신경전도소견은통계적으로유의한음의상관관계를보였다 (Table 2). 초음파의정중신경의단면적, 편평비와 Hi-Ob 척도는원위손목주름의 1 cm 근위부에서통계적으로유의한상관관계를보였으나이외의부위에서는유의한상관관계가없었다. 반면근전도검사척도와초음파소견사이에서는세부위모두에서단면적이 Padua 척도, 운동신경잠복기와의미있는양의상관관계를, 운동ㆍ감각신경진폭과는의미있는음의상관관계를보였으며원위손목주름부위의단면적은감각신경잠복기와의미있는양의상관관계를보였으나편평비는 Hi-Ob 척도, 신경생리학적척도와관련성이없었다 (Table 3). 고찰수근관증후군을진단할때일반적으로임상적평가와전기진단학적검사가시행된다. 수근관증후군은진행정도에따라치료방침이결정되므로이를평가하기위한여러가지척도들이개발되고평가되었다. 임상적척도, 전기생리학적평가등이지속적으로연구되고있으며최근에는영상기술의발달과함께초음파적평가기준에대한연구가활발히진행되고있다. 이전의연구에서임상적평가와전기진단학적검사는서로상관관계를보이는것으로알려져있는데보스턴수근관설문, Simovic 척도, Hi-Ob 척도등의임상척도와 Bland 척도, Padua 척도, Mondeli 척도등의전기생리학적척도의관계에관한연구에서는임상적척도와전기생리학적척도는모두통계적으로유의한양의상관관계를보였고환자가직접평가하는보스턴수근관설문보다의사 58 Korean J Clin Neurophysiol / Volume 12 / December 21
수근관증후군에서임상양상척도및신경전기진단결과와정중신경초음파소견의상관관계 Table 3. Correlation between ultrasonographic data and Hi-Ob scale and electrophysiologic data of median nerve 1 cm proximal to DWC DWC 1 cm distal to DWC Hi-Ob scale Padua scale Motor latency Motor amplitude Sensory latency Sensory amplitude CSA (cm 2 ).35 *.41 *.32 * -.31 *.24 -.26 * Flattening ratio.11.1.7 -.8 -.7.12 CSA (cm 2 ).12.45 *.34 * -.31 *.27 * -.41 * Flattening ratio -.14.6 -..21 -.12.28 CSA (cm 2 ).7.34 *.28 * -.3 *.2 -.33 * Flattening ratio.5 -.5 -.1.22 -.3.34 Values are Spearman s correlation coefficiency. Hi-Ob scale, historical-objective scale; DWC, distal wrist crease; CSA, cross sectional area. * p<.5 가평가하는 Simovic 임상척도와 Hi-Ob 척도의상관계수가높았다는결과를보였다. 1 그러나, 모든상관계수의수치가높지않아임상적척도와전기진단학적검사는약한상관관계를가지는것으로나타났다. 또한, 임상증상에대한설문이순응도와정확도면에서문제가있었다. 본연구에서는임상적척도와전기생리학적평가는이전에알려진바와같이통계적으로유의한상관관계를보였으나전기생리학적평가로사용된 Padua척도, 운동신경전위와감각신경전위의진폭만이상관성을보였고, 잠복기는상관성이없어임상척도와전기생리학적평가는약한상관성을나타냈다. 전기진단학적검사로진단된수근관증후군환자 24명과 14명의대조군을대상으로한연구에서초음파로정중신경의편평비와단면적을구하여환자군과대조군을비교한결과단면적은통계적으로유의한차이가있었으며또한, Phalen s test, Tinel s sign 등의임상적척도도초음파로구한편평비, 단면적과유의한상관관계를보였으며초음파검사의민감도는 89%, 특이도는 1% 로매우높은것으로나타나초음파가수근관증후군의진단에유용한방법이며임상증상과도상관성이높다고주장하였다. 2 본연구에서는임상척도인 Hi-Ob와초음파검사로측정한세지점즉, 원위손목주름 1 cm 근위부, 원위손목주름그리고손목주름 1 cm 원위부의정중신경의단면적과편평비를비교하였을때원위손목주름 1 cm 근위부에서측정한단면적만이상관계수.351로상관관계을보였고 (p<.5), 나머지는상관관계가없는것으로나타났다. 이는 Phalen 검사나 Tinel 검사가증상을유발시키는간단한검사임에비해 Hi-Ob척도는여러항목을측정해야하므로순응도가떨어질가능성이있고또한, 증상의만성화로환자가적응되어감각의평가가신경손상정도에비례하지않기때문일수도있다. 또한요골- 척골접합부, 콩알뼈, 갈고리뼈에서측정한단면적이전기생리학적척도인정중운동신경잠복기, 정중감각신경전도속도와좋은상관성을보이며 13 진단기준으로는 1.3 mm 2 이민감도 97.9%, 특이도 1% 로가장높다고제시된바있는데 14 이번연구에서도전기진단소견과정중신경의단면적은초음파로측정한세부위모두에서통계적으로유의한양의상관관계를보여수근관증후군의진단에유용할뿐아니라전기진단과도잘일치됨을확인했다. 그러나그동안알려져있던것과달리, 본연구에서는편평비는전기진단소견중감각신경전위의진폭과유일하게상관관계를보이고대부분의전기진단척도와통계적으로유의한상관관계를보이지않아임상적용을위해서는보다많은연구가필요할것으로생각된다. 이연구에서는이전의다른논문과는달리초음파를사용하여세부위를측정하여비교하였다. 수근관증후군에서신경의부종이수근관의근위부와원위부까지있으므로이와관련되어증상과신경전기검사와의관련성을보고자하였으며세부위에서측정한신경단면적은모두전기검사와유의한상관성을보였다. 편평비는세부위모두에서신경전기검사와상관성이없는것으로나타나보조적지표로는그역할이제한적일것으로생각된다. 이연구는표본수가 43명 (79수) 으로적고수근관증후군이있는한명의환자를대상으로한것이아니라, 양측손에수근관증후군이있는경우는각각의손을대상으로하여각손에대하여 Hi-Ob 척도로임상증상에대한평가를시행하였으나, 환자가느끼는생활의불편함및통증은양측으로나누어말하기어렵기때문에임상척도측정에제한점이있었다. 또한여성의비율 (88.4%) 이높았고, 중증의환자가주로포함되어천정효과의가능성이있다. 결론적으로초음파는통증을유발하지않으며접근성이뛰어나고공간적정보를제공하며치료를함께시행할수 Korean J Clin Neurophysiol / Volume 12 / December, 21 59
있다는점에서수근관증후군을진단할때현재의전기진단과함께중요한진단방법으로사용될수있으리라생각한다. REFERENCES 1. Jung SH, Paik NJ, Bang MS, Han TR. Comparison of various clinical scales with electrophysiological scales for carpal tunnel syndrome. J Kor Ass EMG 25;7:79-89. 2. Kotevoglu N, Gülbahce-Saglam S. Ultrasound imaging in the diagnosis of carpal tunnel syndrome and its relevance to clinical evaluation. Joint Bone Spine 25;72:142-145. 3. Osterman AL. The double crush syndrome. Orthop Clin North Am 1979;19:147-155. 4. Kang KB, Kim SJ. Electrophysiological findings of patients with upper extremity complaints in diagnosing the carpal tunnel syndrome. J Korean Acad of Rehab Med 1993;17:9-17. 5. Visser LH, Smidt MH, Lee ML. High-resolution sonography versus EMG in the diagnosis of carpal tunnel syndrome. J Neurol Neurosurg Psychiatry 28;79:63-67. 6. Bayrak IK, Bayrak AO, Tilki HE, Nural MS, Sunter T. Ultrasonography in carpal tunnel syndrome: comparison with electrophysiological stage and motor unit number estimate. Muscle Nerve 27;35:344-348. 7. Altinok T, Karakas HM. Ultrasonographic evaluation of agerelated changes in bowing of the flexor retinaculum. Surg Radiol Anat 24;26:51-53. 8. Keleş I, Karagülle Kendi AT, Aydin G, Zöğ SG, Orkun S. Diagnostic precision of ultrasonography in patients with carpal tunnel syndrome. Am J Phys Med Rehabil 25;84:443-45. 9. Park GY, Bae JH, Oh JS, Lim JG, Son DG. Ultrasonographic findings of mild and very mild carpal tunnel syndrome. J Korean Acad Rehab Med 28;32:62-72. 1. Giannini F, Cioni R, Mondelli M, Padua R, Gregori B, D'Amico P, et al. A new clinical scale of carpal tunnel syndrome: validation of the measurement and clinical-neurophysiological assessment. Clinical Neurophysiol 22;113:71-77. 11. Cho JM, Yoon JS, Kim SJ, Park BK, Lee GH, Jeong JS. Feasibility of ultrasonographic area ratio of median nerve in the diagnosis of carpal tunnel syndrome in Korea. J Korean Acad Rehab Med 29;33:627-631. 12. Padua L, LoMonaco M, Gregori B, Valente EM, Padua R, Tonali P. Neurophysiological classification and sensitivity in 5 carpal tunnel syndrome hands. Acta Neurol Scand 1997;96: 211-217. 13. Nakamichi K, Tachibana S. Ultrasonographic measurement of median nerve cross-sectional area in idiopathic carpal tunnel syndrome: diagnostic accuracy. Muscle Nerve 22;26:798-83. 14. El Miedany YM, Aty SA, Ashour S. Ultrasonography versus nerve conduction study in patients with carpal tunnel syndrome: substantive or complementary tests? Rheumatology 24;43: 887-895. 6 Korean J Clin Neurophysiol / Volume 12 / December 21