대한정형외과학회지 : 제 43 권제 3 호 2008 J Korean Orthop Assoc 2008; 43: 379-384 조기발병안면견갑상완근이영양증 - 시상면상척추불균형에서골반신전근의중요성 - 황창주ㆍ강석중 * ㆍ이성우ㆍ안영준 ㆍ김영태ㆍ이동호ㆍ이춘성 울산대학교의과대학서울아산병원정형외과학교실, 인제대학교의과대학부산백병원정형외과학교실 *, 국립경찰병원정형외과 Early-Onset Facioscapulohumeral Muscular Dystrophy - Significance of Pelvic Extensor in Sagittal Spinal Imbalance - Changju Hwang, M.D., Seok-Joong Kang, M.D.*, Sung-Woo Lee, M.D., Young-Joon Ahn, M.D., Yung-Tae Kim, M.D., Dong-Ho Lee, M.D., and Choon Sung Lee, M.D. Department of Orthopaedic Surgery, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea, Department of Orthopaedic Surgery, Pusan Paik Hospital, College of Medicine, Inje University*, Pusan, Korea, National Police Hospital, Seoul, Korea An 11-year-old girl with early-onset facioscapulohumeral muscular dystrophy (FSHD) presented with progressive gait disturbance and lumbar hyperlordosis. The motor power of her pelvic extensor muscles was grade 3. Pelvic tilt and hip flexion were markedly increased as determined by gait analysis. This FSHD case is an impressive example of a patient demonstrating the concept that weak pelvic extensor muscles cannot keep the spine upright and balanced. The most important factor in the development of hyperlordosis is the weakness of the pelvic extensor muscles, and the results of gait analysis exquisitely explain the pathophysiology. The patient stands with her spine hyperextended to maintain upright posture by a compensatory mechanism of relatively strong back extensor muscles. Corrective surgery for lumbar hyperlordosis was not considered as it could eliminate the compensatory lumbar hyperextension, thus making the spine of the patient stoop forward through the hip joint during walking, being caused by the weakness of her pelvic extensor muscles. Key Words: Facioscapulohumeral muscular dystrophy (FSHD), Sagittal Spinal imbalance (SSI), Lumbar Hyperlordosis, Pelvic Extensor muscle, Gait analysis 안면견갑상완근이영양증 (facioscapulohumeral muscular dystrophy, FSHD) 은세번째로흔한유전성근육질환으로서유병율은약 2만분의 1로추정된다 4). 증상은대개 10세를전후하여발현하고비교적양호한임상경과를보이나, 유아기또는소아기초기에발병하는증례가드물게보고되며이러한조기발병안면견갑상완근이영양증 (early-onset FSHD) 은예후가좋지않은것으로알려져있다 2,6-8). 임상양상은매우다양하지만전형적으로 5세이전에안면근육약화, 10세이전에 통신저자 : 이춘성서울시송파구풍납동 388-1 울산대학교의과대학서울아산병원정형외과 TEL: 02-3010-3530 ㆍ FAX: 02-488-7877 E-mail: cslee@amc.seoul.kr 견갑및상완근육의진행성약화가발생하며골반대약화 (pelvic girdle weakness) 및요추과다전만증 (lumbar hyperlordosis) 이뒤따르게된다 2,4,8). 이질환에동반되는주요척추변형인과다전만증에관한병태생리및치료방침은아직까지명확히기술된바가없는데, 저자들은이증례가시상면상척추불균형 (sagittal spinal imbalance, SSI) 에서골반신전근 (pelvic extensor muscle) 의중요성을잘보여주고있다고생각한다. 따라서증례보고와함께이를기술하고자한다. Address reprint requests to Choon Sung Lee, M.D. Department of Orthopaedic Surgery, Asan Medical Center, College of Medicine, University of Ulsan, 388-1, Poongnap-dong, Songpa-gu, Seoul 138-736, Korea Tel: +82.2-3010-3530, Fax: +82.2-488-7877 E-mail: cslee@amc.seoul.kr 379
380 황창주ㆍ강석중ㆍ이성우외 4 인 증례보고명백한근육질환의가족력이없는 11 세여자환자가 Fig. 1. Facial photograph showing bifacial weakness. Note the inability of the patient to close her mouth completely. 근력약화및보행장애를주소로내원하였다. 출생당시에는특별한문제가없었으나 2세경에잘때에도눈을완전히감지못하며무의식적으로입을벌려혀를내밀고있는증상이발현되었고 (Fig. 1) 이때보행을시작한후일어서는것을힘들어하고걷다가쓰러지는일이잦아졌다. 5세부터는팔을어깨높이위로들어올리지못하게되었으며걷거나서있을때복부와둔부가돌출되면서몸이뒤로젖혀지는양상이진행되었다 (Fig. 2). 환아는독립보행이가능하였지만심한동요 (waddling) 및요추과다전만증의소견과함께 10분이상걸으면요통이심해지면서현저하게힘이떨어지고숨이찬증상을호소하였으며기립시골반신전근의약화에의한전방골반경사를보상하기위하여수부와전완부로둔부를지지하는양상 8) 을보였다 (Fig. 2). 양측성익상견갑 (winged scapula) 이있었고뚜렷한족하수 (foot drop) 는없었지만신체검사상상지와하지의모든근육이위축되어있었으며근력도제4 급이하로측정되었다. 특히우측견관절굴곡및외전근, 고관절신전근의근력은제 Fig. 2. Lateral and posterior photographs with the patient standing demonstrate the extremely marked lumbar lordosis with the hands clasped on the posterior hip region for support. This clinical appearance is virtually pathognomonic for early-onset FSHD. Scapular winging is evident in the back view of the patient. Standing radiographs show lumbar hyperlordosis and a horizontal sacrum (arrow).
조기발병안면견갑상완근이영양증 381 3 급이었으며, 한발로서서균형을잡는것이불가능하였다. 척추의굴곡근및신전근근력은각각제3 급, 제4 급이었다. Gower 징후는명확하지않았고가성비대 (pseudo-hypertrophy) 는관찰되지않았다. 음식삼키는것을힘들어하여영양상태가좋지못하였으며저작근의근력과혀조절능력도감소되어있었으나속상수축 (fasciculation) 은보이지않았다. 구음장애 (labial dysarthria) 가있고휘파람을불수없었으며, 경도의안검하수 (blepharoptosis) 와안구운동장애를보였다 (Fig. 1). 시력, 청력및지능은정상이었다. 혈액검사상혈청 creatine kinase 가 466 U/L ( 정상치, 50-250 U/L) 로증가되어있었고, 상지및하지의근전도 / 신경전도와삼각근에서시행한조직검사결과는근병증-myopathy) 에부합하였다. 청력측정검사 (audiometry) 결과는정상이었고, 안저검사상망막혈관병증 (retinal vasculopathy) 이있었다. 분자유전학적검사는시행하지않았다. 뇌및척추의자기공명영상상이상소견은없었고폐기능검사상중등도의제한성환기장애를보였다. 심전도는정상이었다. 척추의기립전후면및측면단순방사선사진상제7 Fig. 3. The deformity of the patient was flexible. Fig. 4. The result of gait analysis. Anterior pelvic tilt increased so severely that it could not be visualized.
382 황창주ㆍ강석중ㆍ이성우외 4 인 흉추부터제 2 요추까지 15 도의우측흉요추측만증과제 1 요추부터제1 천추까지 90도의요추전만증이있었으며후자는비교적유연하였다 (Fig. 2, 3). 보행분석 (gait analysis) 상심한전방골반경사 (anterior pelvic tilt) 와고관절굴곡이과도하게증가되어있는소견을보였다 (Fig. 4). 고찰안면견갑상완근이영양증은임상적, 유전학적및검사실기준이확립된바있지만 7) 여러표현형변이 (phenotypic variant) 가지속적으로발견되어왔다 3,4,6). 1977년 Brooke 1) 이이질환의특이한형태로서유아기형안면견갑상완근이영양증 (infantile FSHD) 을처음기술한이래전세계적으로 60예가량이보고되었으며발생율은전체안면견갑상완근이영양증의 5% 이하일것으로추정된다 2,4). 이에대한통일된진단기준은아직없지만 Brooke 1) 은 2세이전에안면근육약화가나타나는것으로정의하였고, Brouwer 등 2) 은문헌에서의 40예및자신들의 6예를분석한논문에서 5세이전에안면근육약화, 10세이전에견갑대약화 (shoulder girdle weakness) 의증상또는징후가보인경우를포함기준 (inclusion criteria) 으로삼았다. 이러한유아기형또는조기발병안면견갑상완근이영양증은한때고주파범위에서의양측성감각신경성난청 (sensorineural hearing loss) 과망막혈관이상이빈발한다는사실때문에유전학적이질성 (genetic heterogeneity) 의가능성이제기되기도하였으나최근의연구결과에의하면기존의안면견갑상완근이영양증과동일한유전적결손을보이며, 결손된유전자의크기와임상양상의정도및발병시기가항상일치하는것은아니다 2,8). 본증례의환아는비교적전형적인조기발병안면견갑상완근이영양증의임상양상을보이고있지만, 기존의진단기준에서외안근, 저작근, 인두및설근의이환을배제기준에포함시키고있는것에비하면, 안구운동장애, 안검하수증, 저작및연하기능의약화등은흔하지않은증상이다 3,7,8). Shapiro 등 8) 은 9예의유아기형안면견갑상완근이영양증환자중 6예가 12세에서 19세사이에완전히보행이불가능하게되었음을보고하면서기존의질환보다예후가좋지않다고하였는데, 물론예외적인경우도있지만 2,4) 이환자역시향후근력약화와 척추변형의진행, 이로인한호흡기능부전등으로인하여수명이단축될가능성도배제할수없겠다. 척추변형의치료에있어서치료의목표는단순한변형자체의교정이아니라변형의진행을방지하고척추의균형을유지함으로써기능을향상시키는것임은이론의여지가없다. 다양한신경근육성질환이척추의변형을일으키지만대부분은측만증이며조기발병안면견갑상완근이영양증에서발생하는요추과다전만증과같은순수한시상면상의변형은매우드문동시에그치료방침도뚜렷하게제시되어있지않다 8-10). 시상면상의변형은척추자체의문제뿐만아니라골반과이에연결된하지의동력학적인문제가함께연관되어있기때문에 5) 단순히방사선사진상의변형을교정한다고해서그것이유지되고환자에게기능적으로도움이될것인지를심사숙고해야할것이다. 시상면상척추불균형 (SSI) 의수술적치료방침을결정하는데있어서골반경사와골반신전근의중요성은 Lee 등 5) 의퇴행성편평배부 (degenerative flat back, DFB) 에관한연구에서증명된바있다. 퇴행성편평배부는기립또는보행시골반의위치에따라두가지유형으로나눌수있는데, 제1 군은골반신전근이정상으로서후방골반경사를보이는경우이며, 제2 군은골반신전근의약화로인해요추후만에대한골반의보상기전이소실되어현저한전방골반경사를보이는경우이다. 요추의퇴행성후만 (lumbar degenerative kyphosis) 을수술적으로교정한다고하더라도온전한골반신전근에의해보상성후방골반경사가가능하여야술후골반및체간의구부러짐 (stooping) 이호전될수있다. 따라서시상면상척추불균형의수술적치료시온전한골반신전근은중요한필요조건이며, 제2 군에서는술후골반및체간의구부러짐이지속될가능성이높기때문에교정술을시도해서는안된다. 아직까지골반신전근의상태를확인할수있는객관적인방법이확립되어있지는않지만, 보행분석을통해골반경사를평가하는것이그대안으로사용될수있다. 골반신전근이약하면척추의직립및균형이유지될수없다. 안면견갑상완근이영양증에서의요추과다전만증역시퇴행성편평배부 (DFB) 와마찬가지로동적인시상면상척추불균형 (dynamic SSI) 으로서, 본증례는이러한개념을실증하고있다. 변형및불균형의원인이
조기발병안면견갑상완근이영양증 383 Fig. 5. The mechanism of hyperlordosis in this case. The weakness of the pelvic extensor muscles brings about secondary hip flexion contracture (A), and compensatory lumbar hyperlordosis follows (B). Although the lumbar deformity can be corrected surgically or with a brace, stooping will become more severe as the weak pelvic extensor muscles are not be able to overcome the stooping of the pelvis and trunk. 척추자체의구조적변화라기보다는골반과하지의운동역학과관련되어있으며기립및보행시더욱뚜렷해진다는점이 동적 ' 인성질을시사한다. 과다전만증의발생에있어가장중요한요소는 Shapiro 등 8) 이지적했던것처럼골반신전근의약화이고, 보행분석에서관찰되는보행시과도한전방골반경사와고관절굴곡이이를증명한다. 환자는직립자세를유지하기위하여상대적으로강한척추신전근의보상작용에의해척추를과신전하게되는것이다 (Fig. 5). 만약직접적인원인을간과하고단순히요추과다전만증만교정한다면, 이러한과신전에의한보상기전이와해되고, 골반신전근이약하기때문에기립또는보행시고관절을중심으로척추전체가전방으로구부러지면서전방주시가불가능하거나아예걷지못하게될것이분명하다. 따라서이러한환자에서수술적치료는금기이며, 본증례는저자들이과거제안하였던퇴행성편평배부환자에대한치료방침의타당성을확인시켜주고있다 5). 참고문헌 1. Brooke MH: Clinical examination of patients with neuromuscular disease. Adv Neurol, 17: 25-39, 1977. 2. Brouwer OF, Padberg GW, Wijmenga C, Frants RR: Facioscapulohumeral muscular dystrophy in early childhood. Arch Neurol, 51: 387-394, 1994. 3. Dorobek M, Kabzinska D: A severe case of facioscapulohumeral muscular dystrophy (FSHD) with some uncommon clinical features and a short 4q35 fragment. Eur J Paediatr Neurol, 8: 313-316, 2004. 4. Felice KJ, Jones JM, Conway SR: Facioscapulohumeral dystrophy presenting as infantile facial diplegia and late-onset limb-girdle myopathy in members of the same family. Muscle Nerve, 32: 368-372, 2005. 5. Lee CS, Lee CK, Kim YT, Hong YM, Yoo JH: Dynamic sagittal imbalance of the spine in degenerative flat back: significance of pelvic tilt in surgical treatment. Spine, 26: 2029-2035, 2001. 6. Miura K, Kumagai T, Matsumoto A, et al: Two cases of chromosome 4q35-linked early onset facioscapulohumeral muscular dystrophy with mental retardation and epilepsy. Neuropediatrics, 29: 239-241, 1998. 7. Padberg GW, Lunt PW, Koch M, Fardeau M: Diagnostic criteria for facioscapulohumeral muscular dystrophy. Neuromusc Disord, 1: 231-234, 1991. 8. Shapiro F, Specht L, Korf BR: Locomotor problems in
384 황창주ㆍ강석중ㆍ이성우외 4 인 infantile facioscapulohumeral muscular dystrophy. Retrospective study of 9 patients. Acta Orthop Scand, 62: 367-371, 1991. 9. Song EW, Lenke LG, Schoenecker PL: Isolated thoracolumbar and lumbar hyperlordosis in a patient with cerebral palsy. J Spinal Disord, 13: 455-460, 2000. 10. Vialle R, Khouri N, Guillaumat M: Lumbar hyperlordosis in cerebral palsy: anatomic analysis and surgical strategy for correction. Childs Nerv Syst, 22: 704-709, 2005. = 국문초록 = 점차진행하는보행장애와요추과다전만증을보이는 11 세여자환자가조기발병안면견갑상완근이영양증으로진단되었다. 골반신전근의근력이제 3 급이었으며, 보행분석상골반경사와고관절굴곡이현저히증가되어있었다. 이는골반신전근이약하면척추의직립과균형을유지할수없다는사실을보여주는전형적인증례로서, 골반신전근의약화가과다전만증이발생하게된가장중요한원인이며, 보행분석의결과가이를잘설명해주고있다. 환자는직립자세를유지하기위하여상대적으로강한척추신전근의보상작용에의해척추를과신전하게되는것이다. 요추의과다전만증을수술적으로교정하면이러한과신전에의한보상기전이와해되고, 골반신전근이약하기때문에기립또는보행시고관절을중심으로척추전체가전방으로구부러지게될것이분명하다. 따라서이러한환자에서수술적치료는금기이며, 이는저자들이과거제안하였던퇴행성편평배부환자에대한치료방침의타당성을실증하고있는예이다. 색인단어 : 안면견갑상완근이영양증, 시상면상척추불균형, 요추과다전만증, 골반신전근, 보행분석