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Case Report J Korean Orthop Assoc 2011; 46: 438-442 http://dx.doi.org/10.4055/jkoa.2011.46.5.438 www.jkoa.org Far-out Stenosis by the Lumbosacral Transitional Vertebrae 김영훈 윤기식가톨릭대학교서울성모병원정형외과 요천추이행성척추의만성요통과인접분절추간판의퇴행성변화에대한임상적의미에대하여는이견이많다. 이중이행성척추의이형성횡돌기, 하부천추익상부의변형된관절형성과이부위에서의신경근압박에의한요천추부극외척추관협착증에대하여는증례를통하여드물게보고되고있으며, 보존적치료에반응하지않은경우전방및후방감압을통한수술적치료가제시되고있다. 저자들은이행성척추에의한요천추부의극외척추관협착증환자를경험하였으며, 이를후외방접근을통한감압으로성공적인치료를경험하였기에이를문헌고찰과함께보고하고자한다. 색인단어 : 이행성척추, 극외척추관협착증, 후외방감압 요천추이행성척추는요추의천추화또는천추의요추화변형으로관찰되는선천성척추기형으로일반인구의 4-30% 에서관찰된다. 이기형의임상적의미는수술적치료에있어서병변척추의분절파악에있어서중요한고려의대상이며, 요통의하나의원인에대해서는이견이있으나, 많은보고에서요통과관계가있음이주장되고있다. 또한, 증례보고를통하여이들의극외척추관협착증증세유발에대하여도드물게보고되고있다. 1,2) Abe 등은이형성횡돌기와천추의익상부의비정상적인관절형성으로인한신경근의압박을전방감압술로치료한것을보고하였으며, 1) 이후이러한병변에대하여전방접근대신후방접근을통한성공적인감압이보고되고있다. 2) 그러나, 요천추이행성척추변형에의한극외척추관협착증및이의치료에대한국내의보고는없기에본원에서치료한증례를문헌고찰과함께보고하고자한다. 증례보고 55 세남자로 8 개월전가벼운낙상이후시작된우측둔부및하 접수일 2010 년 11 월 16 일게재확정일 2011 년 4 월 27 일교신저자김영훈서울시서초구반포동 505, 서울성모병원정형외과 TEL 02-2258-6118, FAX 02-535-9834 E-mail boscoa@empal.com 지의방사통을주소로내원하였다. 과거의치료력상이기간동안수차례의보존적치료를시행하였으나증세의호전은없었으며, 보존적치료로이학요법과경막외주사및신경근차단술을수차례시행받았으나증세의호전은없었다. 과거력상특이소견은없었다. 내원시이학적검사에서하지직거상검사는우측이 80도에서우측둔부및우하지의방사통을호소하였으며, Thomas 검사및 Patrick 검사에서는음성이었다. 신경학적검사상근력의저하는없었으며, 제1천추신경근분포부위의감각둔화를호소하였다. 건반사는정상이었으며, 병적반사의증거는없었다. 초진시측정한요통및하지동통에대한 Visual analog scale (VAS) 7점및 Oswestry disability index (ODI) 59점이었다. 내원시촬영한단순방사선상천추의요추화변화및 Castellvi's type IIa 3) 의요천추이행성척추변형이관찰되었으며, 우측횡돌기의천추익상부와가관절형성소견이관찰되었다 (Fig. 1). 타기관에서촬영한자기공명영상소견으로는추간판의돌출및추간공부위의신경근압박소견은없었으며, 제6요추 ( 제1천추의요추화 ) 체의외측과우측의횡돌기와의간격의협소화를확인할수있었다. 요천추부위의이행성척추에의한극외추간공협착증을확인하기위하여전산화단층촬영및근전도검사를추가로시행하였다. 전산화단층소견상과성장되어있는제6요추의우측횡돌기와추체에의한극외추간공의협착소견을확인할수있었으며 (Fig. 2), 근전도검사상우대둔근및무지외전근에서의비정상자발전위가있어우측제1천추신경근병증을확인할수있었다. 이상 대한정형외과학회지 : 제 46권제 5호 2011 Copyright 2011 by The Korean Orthopaedic Association This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

439 으로제1천추의이행성척추변형및이부위에서의극외척추관협착증에의한제1천추신경근의압박으로진단하여이에대하여후방감압을시행하였다. 수술적치료는 Wiltse 접근방법으로후외방접근을이용하였으며, 장골능의후측부에의한공간의협소화로일반적수술견인장치를사용하기어려울것으로예상하여수술공간을최대한확보하기위하여 METRX tubular retractor (Medtronic Sofamor Danek, Memphis, TN) 를이용하여현미경하 에감압을시행하였다. 수술중 C-arm을이용하여 tubular retractor의위치를확인하였으며, 후관절의외측으로횡돌기를노출시킨후추체의외측및횡돌기의전면부까지감압을시행하였다. 현미경하횡돌기의전방및내측의척추체의완전한노출및신경근의주행을확인한후수술을마쳤다. 수술후촬영한전산화단층촬영상우측의제6요추횡돌기의내측부위의감압을확인할수있었다 (Fig. 3). 수술직후환자는하지의동통의감소를경험하였으며, 수술후 3개월에측정한 VAS 3점및 ODI는 30점으로수술전증세의회복을경험하였다. 고찰 Figure 1. Plain radiographs show the right abnormal articulation of the enlarged transverse process of the lowest lumbar spine with the sacral alar portion (arrow). It can be classified as a type IIa of the Castellvi s classification. 요천추부이행성척추는제5요추의천추화또는제1천추의요추화변형으로정의될수있는선천성척추기형으로 Castellvi의형태적분류로이형성된횡돌기의형태와하부의천추와의가동성 (diarthrodial) 관절또는유합의형태에따른형태학적분류가이용되고있다. 이병변과관련되어요통의원인및인접분절의추간판퇴행성변화등의임상적의미에대하여는논란이있다. 많은연구에서이기형의임상적의미가보고되고있으며, 요통의원인으로제시되고있는근거는 1) 이행성척추가있는경우역학적부하의변화로상위분절의추간판을포함한관절의퇴행성변화가촉진되며, 2) 이형성된횡돌기와하부의천추익상부의가동성관절의퇴행성변화가요통의원인이되며, 3) 이행성척추의유합또는가동성관절형성에따른반대측후관절의응력증가로인한관절증의원인등이있다. 4-6) 그러나, Tini 등 7) 은 4,000 명의환자들분석에서이행성척추와요통의관계가없다고주장하였으며, Elster 8) 는이행성척추의유무가추간판의병변및척추관협착증의발생과관계없다고주장하였다. 따라서이행성척추 Figure 2. Preoperative radiographs. (A, B) MR images show no definite compression of the nerve root at central and foraminal portions. (B, C) Right lumbosacral tunnel is encroached by the hypertrophied abnormal transverse process (arrow).

440 김영훈 윤기식 Figure 3. Intraoperative microscopic image shows decompressed nerve root (arrow head) and exposure of anteromedial side of right transverse process (arrow). Postoperative CT shows the decompressed portion of right lumbosacral tunnel (arrow). 변형의요통의발생원인에대하여는아직이견이많다. 이행성척추에의한극외척추관협착에의한신경근의압박은드물게보고되고있으며, Wiltse 등의보고이후해부학적인연구 9) 를통하여제5요추신경근의제5요추체, 요천추인대및천추익상부로형성되는추간공외공간인요천추터널 (lumbosacral tunnel) 부위에서의압박의가능성이주장되었으며, 이러한임상증례의보고가있었다. 2,9,10) 요천추이행부위에서의추간공외측에서의신경근의압박에대한임상증례의보고는제5요추체의전외측부위의골극에의한것으로전방혹은후방적접근을통하여주로골극의제거를통한수술적치료의결과를보고하였다. 10) 추간공외측협착증원인의다른하나인이행성척추변형에의한신경근의압박에대해서 Abe 등이처음보고한이후드물게보고되고있다. Abe 등 1) 은수술적치료로전방복막외접근을통한감압을보고하였고, Ichihara 2) 는이행성척추변형에동반된증례에서신경근차단술로치료한증례와보존적치료에실패한증례에서후외방접근을통한수술적감압으로치료한증례를보고하였다. 이러한보고들에서와같이이행성척추변형에의한요천추이행부의추간공외측의신경근압박은매우드문질환으로본증례에서도수개월간의신경근의압박증세가있었으나, 정확한신경근의압박소견을영상학적인검사를통하여확인할수없어보존적치료및수차례의신경근차단술을시행하였으나실패하였다. 본증례의경우천추의요추화변형이있었으며, Castellvi 분류상 type IIa형으로우측의이형성된횡돌기하부와천추익상부의관절형성이있었으며, 근전도검사상제1천추신경의지배영역의이상소견이있어이부위에서의극외척추관협착으로진단하고감압술을시행하였다. 이미기술한증례보고들에서각각전방또는후방의감압이치료방법으로제시되었으며, 전방감압을주장한 Abe 등은후방접근으로추체의전면부까지의접근시 출혈및시야확보의제한이예상되어전방접근을이용한감압을시행하였다고하였으나, 추간공외측의감압에대하여후방접근을통하여충분한감압을시행할수있다는보고들이있으므로 2,10) 본저자들또한후외방도달법을이용하여감압을실시하였다. 그러나후방접근시장골능의후측부의돌출로인하여수술시야확보의어려움이있을것으로예상하여이에대하여 tubular retractor를이용하였으며, 이를통하여충분한시야를확보할수있었다. 요천추부이행성척추변형의임상적의미에대하여는아직이론의여지가있으며, 4-7) 이변형에대하여본저자를포함하여많은임상의들이이를간과하는경향이있는것이사실이다. 그러나, 이행성척추변형은수술및신경근차단술등을시행할때정확한신경근의선택에있어서간과해서는안되는부분이며, 특히요천추이행부위신경근추간공외측의협소화에의한신경근의압박소견에대하여도세심한주의가필요할것으로생각된다. 참고문헌 1. Abe E, Sato K, Shimada Y, Okada K, Yan K, Mizutani Y. Anterior decompression of foraminal stenosis below a lumbosacral transitional vertebra. A case report. Spine (Phila Pa 1976). 1997;22:823-6. 2. Ichihara K, Taguchi T, Hashida T, Ochi Y, Murakami T, Kawai S. The treatment of far-out foraminal stenosis below a lumbosacral transitional vertebra: a report of two cases. J Spinal Disord Tech. 2004;17:154-7. 3. Castellvi AE, Goldstein LA, Chan DP. Lumbosacral transitional vertebrae and their relationship with lumbar extradural defects. Spine (Phila Pa 1976). 1984;9:493-5.

441 4. Bertolotti M. Contribute alla conoscenza dei vizi di differenzazione del rachide con speciale reguardo all assimilazione sacrale della v lombare. La Radiologia Medica. 1917;4:113-44. 5. Epstein JA, Epstein NE, Marc J, Rosenthal AD, Lavine LS. Lumbar intervertebral disk herniation in teenage children: recognition and management of associated anomalies. Spine (Phila Pa 1976). 1984;9:427-32. 6. Luoma K, Vehmas T, Raininko R, Luukkonen R, Riihimäki H. Lumbosacral transitional vertebra: relation to disc degeneration and low back pain. Spine (Phila Pa 1976). 2004;29:200-5. 7. Tini PG, Wieser C, Zinn WM. The transitional vertebra of the lumbosacral spine: its radiological classification, incidence, prevalence, and clinical significance. Rheumatol Rehabil. 1977;16:180-5. 8. Elster AD. Bertolotti's syndrome revisited. Transitional vertebrae of the lumbar spine. Spine (Phila Pa 1976). 1989;14:1373-7. 9. Nathan H, Weizenbluth M, Halperin N. The lumbosacral ligament (LSL), with special emphasis on the "lumbosacral tunnel" and the entrapment of the 5th lumbar nerve. Int Orthop. 1982;6:197-202. 10. Matsumoto M, Chiba K, Nojiri K, Ishikawa M, Toyama Y, Nishikawa Y. Extraforaminal entrapment of the fifth lumbar spinal nerve by osteophytes of the lumbosacral spine: anatomic study and a report of four cases. Spine (Phila Pa 1976). 2002;27:E169-73.

442 김영훈 윤기식 Far-out Stenosis by the Lumbosacral Transitional Vertebrae Young Hoon Kim, M.D., and Ki Sik Yoon, M.D. Department of Orthopedic Surgery, Seoul St.Mary s Hospital, The Catholic University of Korea, Seoul, Korea Surgeons still have many different views on the clinical significances of the lumbosacral transitional vertebrae as one of the causes of chronic low back pain and a higher incidence of adjacent disc degeneration. Moreover, in rare case reports, compression of the exiting nerve root due to abnormal articulation between the hypertrophied transverse process and the sacral ala has been proposed as one of the reasons for the far-out lumbosacral stenosis. Anterior or posterior surgical decompression is recommended in the cases that are refractory to conservative treatment. We reviewed the related literatures and report on a case that suffered from the farout stenosis due to lumbosacral transitional vertebra and this was successfully treated by decompression using the posterolateral approach. Key words: transitional vertebra, far-out stenosis, posterolateral decompression Received November 16, 2010 Accepted April 27, 2011 Correspondence to: Young Hoon Kim, M.D. Department of Orthopedic Surgery, Seoul St. Mary s Hospital, 505, Banpo-dong, Seocho-gu, Seoul 137-701, Korea TEL: +82-2-2258-6118 FAX: +82-2-535-9834 E-mail: boscoa@empal.com