Journal of Korean Society of Spine Surgery Tardy Spinal Cord Compression without Bone Cement Leakage after Kyphoplasty - A Report of 3 Cases - Dong Ki Ahn, M.D., Dea Jung Choi, M.D., Hoon Seok Park, M.D., Chang Wook Yoo, M.D J Korean Soc Spine Surg 2010 Mar;17(2):104-110. Originally published online June 30, 2010; doi: 10.4184/jkss.2010.17.2.104 Korean Society of Spine Surgery Department of Orthopaedic Surgery, Ewha Womans University Collge of Medicine #911-1 Mok-dong, Yangcheon-gu, Seoul, 158-710, Korea Tel: 82-2-2646-6808 Fax: 82-2-2646-6804 Copyright 2010 Korean Society of Sping Surgery pissn 2093-4378 eissn 2093-4386 The online version of this article, along with updated information and services, is located on the World Wide Web at: http:///doix.php?id=10.4184/jkss.2010.17.2.104 Subscriptions: Information about subscribing to Krspine is online at http:///index.php?main=subscription. 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. Downloaded from by on June 30, 2010
Case Report pissn 2093-4378 eissn 2093-4386 J Korean Soc Spine Surg. 2010 Jun;17(2):104-110. doi: 10.4184/jkss.2010.17.2.104 Tardy Spinal Cord Compression without Bone Cement Leakage after Kyphoplasty - A Report of 3 Cases - Dong Ki Ahn, M.D., Dea Jung Choi, M.D., Hoon Seok Park, M.D., Chang Wook Yoo, M.D. Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital, Seoul, Korea Study Design: This is a case report Objective: We report here on three cases of late spinal cord compression without bone cement leakage after kyphoplasty from the view point of the common characteristics, the suspected etiologies and the performed treatments, and we propose a technique to prevent this kind of complication. Summary of the Literature Review: Kyphoplasty is widely accepted as an effective and safe treatment for osteoporotic vertebral compression fracture (VCF). Complicated compression fractures and even bursting fractures with a compromised spinal canal are currently indicated for kyphoplasty. The wide spread application of kyphoplasty may be mainly due to reducing the complication rates associated with cement leakage and possible restoration, even though partially, of a vertebral kyphotic deformity. Materials and Methods: we experienced three cases of newly emerged complications that caused delayed neurologic compromise after uneventful kyphoplasty without any immediate neurologic deficits. MR imaging was done to find the pathologic regions and surgical treatment was performed. Results: Refracture of an augmented vertebra at the conus medullaris level can cause late occurring spinal cord compression without compromising the spinal canal. Posterior instrumentation and posterior fusion with posterior decompression were effective treatments. Conclusions: The anatomical peculiarity of the conus medullaris and the dynamic irritation of the spinal cord by a bone cement mass after refracture of an augmented vertebral body can be the causes of late spinal cord compression after kyphoplasty. The neurologic symptoms were treated by posterior decompression and fusion. This kind of complication can be prevented by injecting a sufficient amount of bone cement with a shape to support both endplates. Key words: Kyphoplasty, late spinal cord compression 서론 척추성형술시전방또는외측으로누출이발생할경우대부분신경학적증상을일으키지않는다고보고되지만, 척추관내또는신경공내누출은신경학적합병증을발생시킬수있으며골시멘트제거술이시행된예도보고되고있다. 1,2) 그러나지금까지보고된예는시술중발생하여즉각적인신경학적합병증이동반된보고였으며누출된골시멘트의직접적인압박에의한경우가대부분이었다. 척추성형술의만족할만한보고들에힘입어적용범위가점차넓어지면서불안정한형태의골다공증성추체골절에도점차시술이많아지고있으며이에따라기존에보고되지않았던새로운형태의지연성합병증이발생하게된것으로사료되어문헌고찰과함께그발생원인과치료에대하여보고하고자한다. Received: February 16, 2010 Revised: May 13, 2010 Accepted: May 20, 2010 Published Online: June 30, 2010 Corresponding author: Dae Jung Choi, M.D. Department of Orthopedic Surgery, Seoul Sacred Heart General Hospital 40-12 Chungryangri-dong, Dongdaemoon-gu, Seoul 130-010, Korea TEL: 82-2-966-1616, FAX : 82-2-968-2394 E-mail: niceosu@freechal.com 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. 104 Copyright 2010 Korean Society of Spine Surgery
Journal of Korean Society of Spine Surgery Tardy Spinal Cord Compression after Kyphoplasty 증례보고 증례 1. 65세여자로골밀도는 T-점수 -3.08이었으며체질량지수 (BMI: Body mass index) 는 33이었다. 가벼운외상후배부동통이발생하여단순방사선검사및자기공명영상검사상제 12 흉추의압박골절이발견되었다. 골절은하부종판을침범하였으며척추관의침범은없었다. 척추관의침범은자기공명영상검사의축상면상에서척추관면적의감소로측정하였다. 전방붕괴추체높이는 67%, 추체후만각 20도로소실되었으며골절 발견 3주에추체후만변형이더진행하지는않았으나동통의감소소견이없어풍선척추성형술을시행하였다. 술후추체후만각은 3도로감소하고전방붕괴추체높이는 79% 로증가하였다. 골시멘트의주입형태는추체의하부에만위치하고지상교합 (interdigitation) 은되지않았으며추체외측과하부추간판으로누출이있었다. 술후동통은소실되어흉요천추보조기착용하에당일부터보행및실내활동을시작하였다. 술후약 4주후에외상없이보행의불편과배부동통이다시발생하여자기공명영상검사를한결과제 1요추에새로운골절이발생하였다. 보존적치료로지속적인보조기착용을권고하였으나술후 13주에 Nurick 4등급의보행장애와배뇨장애를호소하며재차내원하였다. 자기공명영상검사상골시멘트가제 12흉추와제 1요추사이의추간판으로이동하였으며추체간격은소실되고제 12흉추의하부종판과섬유륜이척수원추를압박하였다. 척추관의침습은상부추체하연을기준으로하여약 30% 정도만발생하였으나척수원추의부종에의해뚜렷한압박소견이있었다 (Fig. 1). 수술적치료로후방접근법을이용하여제 12흉추와제 1요추사이수핵과골시멘트일부를제거하고추체간골이식을하였다. 척추경나사못과강봉을사용하여제 10흉추에서제 3요추까지후방고정술을하였다. 술후신경증상은즉시회복소견을보였으며 2년추시상 Nurick 2등급으로호전되고배뇨장애는소실되었다. 증례 2. 72세여자환자로골밀도는 T-점수 -3.14 이었으며체질량지수는 29.6 이었다. 내원 2개월전부터지속적인배부동통과양측분부동통을호소하였다. 단순방사선검사상제 12흉추의골절과추체내공기음영이관찰되었다. 전방추체의높이는 29% 로감소하였으며추체후만각은 27도였다. 해당추체후연의상부에의해약 38% 의척추관침범이있었다. 풍선척추성형술을시행하자동통은즉시감소하였다. 골시멘트의주입양상은상, 하종판사이전체에지상교합이 Fig. 1. (A) T12 compression fracture was noticed in 65-year old female patient. (B) Compressed conus medullaris is noticed at 4-month follow-up after kyphoplasty. (C) Posterior decompression and fusion with posterior instrumentation were performed. 없는견고한형태로되었으며시술직후추체외골시멘트누출 은없었다. 술후에추체후만각은 13 도로회복되었으며전방붕 괴추체높이는 62% 로정복되었다. 수술당일부터흉요천추보 조기를착용하고보행훈련을시작하였다. 술후약 7 주에바닥에가볍게주저앉은후배부동통과 Nurick 3 등급의보행장애, 배뇨장애를호소하였다. 자기공명 영상검사상이전해당추체의골시멘트가충전되지않은부 위에재골절소견이있고제 10, 11 흉추, 제 1 요추의골절이추 가로발생하였으며척수원추의심한부종과압박소견이관 찰되었다 (Fig. 2). 그러나척추관의침습은 38% 로변화가없었 다. 제 9 흉추에서제 2 요추까지후방유합술을하고 2 년추시상 Nurick 1 등급으로호전되고배뇨장애는소실되었다. 증례 3 74 세여자로골밀도는 T- 점수 -4.34 였으며체질량지수는 26.6 이었다. 내원 2 개월전타병원에서제 12 흉추에풍선척추 성형술을받았다. 수술후약 1~2 주경과부터보행량이점차많 아지면서양측하지의동통및 Nurick 2 등급의보행장애가발 생하였다고하였다. 본원내원시단순방사선검사상전방붕괴 추체의높이는 53%, 추체후만각은 19 도의소견을보였고자기 공명영상검사상해당추체에재골절소견이있고해당추체후 면이척추관으로돌출되어약 30% 정도의침습을보였다 (Fig. 3). 후방감압술과제 9 흉추에서제 2 요추까지후방기기고정술 을시행하였다. 술후 1 년추시상 Nurick 1 등급으로호전되었 다. 고찰 경피적척추성형술은골다공증성척추압박골절이발생한 고령의환자에서통증조절면에서탁월함이인정되었고있으나 105
Dong Ki Ahn et al Volume 17 Number 2 June 2010 Fig. 2. (A) T12 compression fracture resulted in severely collapsed deformity. (B) Collapse of the cement-augmented vertebral body is noticed about 7 week follow-up after a minor trauma with new compression fractures at T10, T11, and L1 verterbrae. Conus medullaris looks compressed and redundant with signal change on T1 weighted sagittal MR. (C) Posterior fusion and posterior instrumentation were performed without posterior decompression. (D) 2-year follow-up T1-weighted sagittal MR shows relief of compressed and swollen conus medullaris. 골시멘트누출의문제와해당추체의재함몰및추체후만각변형을교정할수없다는문제점을가지고있다. 3) 이후추체후만변형의교정을위하여풍선척추성형술이개발되었으나추체후만각의교정은부분적으로만가능하며, 해당추체상, 하분절을포함한국소시상각및전체시상면교정에는의미있는효과는없는것으로보고되고있다. 4,5) 풍선척추성형술은풍선확장시형성된추체내의공간에높은점도의골시멘트를낮은압력으로주입할수있으므로골시멘트누출로인한합병증의발생율을감소시킬수있는것으로보고되고있으나추체해면골과지상교합을이루지못한골시멘트괴에의해인접분절종판으로응력전달이증가하고이로인하여인접추체압박골절을증가시킬수있다는보고가있어경피적척추성형술보다풍선척추성형술이더유용한지에대하여서는논쟁의여지가남아있다. 또한인접추체압박골절및해당추체의재골절등의발생에는여러가지내적, 외적위험인자들이관여하고있어서단지기술적인방법차이에서이러한문제들이더발생한다고생각되지는않는다. 4) 경피적척추성형술또는풍선척추성형술후해당추체의재골절은저자들에따라 3.21%~63% 가발생하는것으로보고되었으며위험인자로는무혈성괴사, 스테로이드의장기적사용, 골다공증치료제를사용하지않은경우, 전방추체의복원을많이한경우그리고불충분한골시멘트의주입등이제시되고있다. 6,7) 반면척추의신전운동은이와같은골절을감소시킬수있는것으로연구된바도있다. 8) 그러나이전연구자들의증례들에서는해당추체재골절의의발생유무또는추가적인인접추체의압박골절에의한동통과변형이논점이되었을뿐, 이로인한척수압박에따른신경학적합병증발생에대해서는언급이없었다. 적은수의증례이지만저자들의경험한상기증례들의공통점은풍선척추성형술을시행받았다는것, 골시멘트로강화된해당추체의재골절이있었다는것, 척수원추 (conus medullaris) 높이에해당하는제 12흉추부위에서척수원추압박이발생하였다는것이다. 또한골절편의척추관침범이 50% 를넘지않았음에도불구하고척수원추의부종과이에따른압박소견이지연성으로발생하였다는것이특이하였다. 이러한소견은골다공증성척추압박골절에대하여저자들이보존적치료를시행한경우에는관찰된바가없었다. 또한본증례들에서는골시멘트가척추관내누출된경우는없었으며소량의척추관내의골시멘트누출은신경증상을일으키지않는다는보고가대부분이므로, 척추관내누출된골시멘트에의해직접적 106
Journal of Korean Society of Spine Surgery Tardy Spinal Cord Compression after Kyphoplasty Fig. 3. (A,B) Weighted MR show suspected compression of conus medullaris by cement-augmented vertebral body. (C) Posterior decompression and fusion with posterior instrumentation were performed. (D,E) T2 weighted MR shows that malunited posterior wall fragment of cement-augmented vertebral body does not further compress conus medullaris. 으로골시멘트성분에의한화학적자극이나물리적자극이신경증상의원인일것으로는생각되지않는다. 상기증례의발생의원인으로첫째, 생역학적인자가고려되어야한다. 풍선척추성형술시풍선확장으로해면골은단단히압박되므로골시멘트와지상교합을형성하지않으며주입된골시멘트는견고한괴 (solid mass) 형태로추체내존재하게된다. 또한골다공증성추체의해면골은상당히응력에취약한부분으로생각되므로골시멘트괴의표면에서접촉하고있는해면골주는적은응력발생에도쉽게파손되어골시멘트괴와분리될수있을것으로생각된다. 특히골절된추체후연이척추관침습을하고있는경우에, 추체내위치한견고한골시멘트괴가상, 하종판을지지하여정복된후연을지속적으로유지할정도로충분한높이가되지못하면, 환자의기립운동이시작되면서종판과골시멘트괴사이의해면골은서서히압박되어재함몰되거나, 외상이반복되어해당추체의재골절이발생하면골시멘트괴의역동적 (dynamic) 미세전후방운동이발생할수있는유격이형성될수있다. 이러한골시멘트괴의역동적미세전후방운동은추체후연의골편을반복적으로자극하고이응력은척수로전달되어척수부종을발생시킬수있을것으로생각된다. 둘째, 해부학적특성을고려해볼수있다. 척수의요추확장부 (lumbar enlargement) 는제 9번흉추에서부터점차넓어져서제 12번흉추에서가장커지며이후급격히좁아지면서척수원추형태를하고있다. 9) 따라서제 12번흉추의척추관너비는척수너비를고려할때상대적으로좁기때문에이부위에서의척추부종이발생할경우이차적으로후외방의척추관에의한신경압박이발생할수있을것으로생각된다. Watanabe 등 10) 은장분절에대한후방기기고정술을시행한경우유합최상위척추또는최상위인접척추압박골절의발생위험인자에대한보고에서, 술후비교적조기에발생하여급격한신경관압박증상까지를발생하는척추압박골절및후만변 107
Dong Ki Ahn et al Volume 17 Number 2 June 2010 Fig. 4. (A) Preoperatively T12 compression fracture is noticed. (B,C) Postoperative radiographs show cement mass enough to support upper and lower endplates, performed with vertebroplasty with 2.8mm-daimetered cement filler. (D) 2-month follow-up radiograph shows stable cement pillar mass, even though the slight recollapse of the cementaugmented vertebra. Fig. 5. A technique to infuse cement enough to support both endplates. (A) Cement fillers should be plated in the middle of the opposite endplate to a fractured site. (B) Cement was fully infused into non-fractured but fragile, scanty cancellous portion. (C,D) The amount of cement enough to support both endplate was infused successfully until the cement advanced into fractured portion without cement leakage. 108
Journal of Korean Society of Spine Surgery Tardy Spinal Cord Compression after Kyphoplasty 형을발생시키는위험인자중하나로 26.7이상의체질량지수 (BMI: body mass index) 를제시하고있다. 저자들의증례모두체질량지수가 26이상의과체중환자였다. 따라서과체중 (BMI: 25~29.9), 비만 (BMI: 30.0~40.0) 및고도비만 (BMI: >40) 에해당하는환자에서제 12흉추에상기와같은압박골절의발생하여척추성형술을시행하였다면, 추시중해당추체의재골절발생시신경증상이발생할수있을가능성을간과해서는안될것으로생각된다. 특히고령의환자에서는팔, 다리체지방의소실이많고체지방은주로상체및복부에집중되므로키와몸무게로산출된체질량지수는저평가되어있다는것또한고려되야할사항이다. 이러한합병증을예방하기위해서는제 12 흉추에서의척추성형술시주입되는골시멘트의양상은가급적재함몰및재골절을피할수있도록상, 하종판을골시멘트가지지할수있을정도의충분한량의골시멘트를주입해야하면서도해면골과골시멘트경계가지상교합을형성하는형태의골시멘트주입이이상적일것으로생각된다. 이를위해서는해면골을압박시켜버리는풍선사용을지양하고, 일측종판을침범하는골절의경우골절이안된종판부의중앙에골시멘트충전관의출구끝을위치하여골절이없으면서도해면골의밀도가낮은취약한부위부터골시멘트를주입하면이부위에서골시멘트가해면골과먼저지상교합을이루도록유도할수있을것이다. 골절이없는골다공증성해면골부위에골시멘트가충분히채워지고나면자연스럽게골시멘트는골절부위로이동하면서충전이이루어지게된다. 이러한방법으로골시멘트괴의많은부분은지상교합을이루어역동적미세전후방운동이발생하는것을예방할수있으며, 상, 하종판을지지할수있는충분한량의골시멘트주입으로해당추체의재함몰과재골절을최대한방지할수있을것으로예상된다 (Fig. 4,5). 치료에있어서보존적요법은효과를거둘수없었다. 수술적치료에있어서골절추체후연의척추관침범이많지않은경우에는추체제거술또는광범위한후방감압술등없이도좋은결과에도달하였다. 전방도달법을사용할경우성형추체의제거와함께전방재건술이불가피하나, 척추관의침습이 50% 미만으로척수의압박이발생하지않을조건인것을고려하여광범위한수술적치료를피하고후방접근법을사용하였다. 증례 2 의경우에서처럼척추관의직접감압술없이후방기기고정술및후방유합술만으로치료하였으나보행장애및배뇨장애가호전된것을감안하면술전자기공명영상검사상으로는파악할수없는척수에대한역동적인응력전달과이와관련된척추압박이존재하였을것으로생각되며후방기기고정술및후방유합술은추체내견고한골시멘트괴에의한발생하는역동적미 세전후방운동으로인한역동적척수자극을없애는데중요한역할을한것으로생각된다. REFERENCES 1. Kim KT, Suk KS, Kim JM, Park KC. Root injury after percutaneous vertebroplasty in compression fracture: case report. J Korean Soc Spine Surg. 2001;8:181-5. 2. Hiwatashi A, Westesson PL. Vertebroplasty for osteoporotic fractures with spinal canal compromise. Am J Neuroradiol. 2007;28:690-2. 3. Chen JK, Lee HM, Shih JT, Hung ST. Combined extraforaminal and intradiscal cement leakage following percutaneous vertebroplasty. Spine. 2007;32:358-62. 4. Ahn DK, Choi DJ, Lee S, Kim KS, Kim TW, Chun TW. The efficacy of kyphoplasty on osteoporotic vertebral compression fracture: A 1-year follow-up study. J Korean Soc Spine Surg. 2009;16:79-88. 5. Pradhan BB, Bae HW, Kropf MA, Patel VV, Delamarter RB. Kyphoplasty reduction of osteoporotic vertebral compression fractures: correction of local kyphosis versus overall sagittal alignment. Spine. 2006;31:435-41. 6. Lin WC, Lee YC, Lee CH, et al. Refractures in cemented vertebrae after percutaneous vertebroplasty: a retrospective analysis. Eur Spine J. 2008;17:592-9. 7. Shin DA, Kim KN, Shin HC, Kim SH, Yoon DH. Progressive collapse of PMMA-augmented vertebra: a report of three cases. Zentralbl Neurochir. 2008;69:43-6. 8. Huntoon EA, Schmidt CK, Sinaki M. Significantly fewer refractures after vertebroplasty in patients who engage in back-extensor-strengthening exercises. Mayo Clin Proc. 2008;83:54-7. 9. Grey HD, Clemente C. The text book of anatomy of the human body 13thed. Philadelphia, Lea & Febiger:960-1, 1985. 10. Watanabe K, Lenke LG, Bridwell KH, Kim YJ, Koester L, Hensley M. Proximal junctional vertebral fracture in adults after spinal deformity surgery using pedicle screw constructs: analysis of morphological features. Spine. 2010;35:138-45. 109
Dong Ki Ahn et al Volume 17 Number 2 June 2010 풍선척추성형술후골시멘트누출없이발생한지연성척수압박 - 3 예보고 - 안동기 최대정 박훈석 유창욱서울성심병원정형외과 연구계획 : 증례보고목적 : 풍선척추성형술후골시멘트누출이없이지연성으로발생한척수압박 3예을보고하고, 증례의공통적특성, 발생가설과치료법및합병증을예방하기위한기술적인방법을제시하고자한다. 선행문헌의요약 : 풍선척추성형술은골다공증성척추압박골절에대하여효과적이고안전한치료방법으로널리인정되어있다. 추체의후만변형을부분적이지만어느정도정복이가능하게하고골시멘트누출에따른합병증의위험성을감소시킬수있는장점이있으며, 최근에는복잡한압박골절뿐만아니라척추관침범이있는형태의방출성골절에서도성공적인결과가보고되어점차사용범위가넓어지고있다. 대상및방법 : 저자들은신경증상을동반하지않은척추압박골절에서풍선척추성형술시행시골시멘트누출로인한신경학적합병증의발생이없이성공적인시술후, 일정시간이지나서신경증상이발생된 3예를대상으로하였다. 자기공명영상검사로척수부종소견을확인하고후방감압술및후방유합술을시행하였다. 결과 : 척수원추부에서성형된척추체의재골절은척추관침범의증거없이도지연성척수압박을유발할수있으며후방감압술및후방유합술로신경증상이회복되었다. 결론 : 풍선척추성형술후발생한지연성척수압박은척수원추부위의해부학적특성과성형추체의재골절후발생하는골시멘트괴의역동적자극에의한것으로생각되며후방감압술및유합술로신경증상이회복되었다. 척추성형술시상하종판을지지할수있는형태로충분한골시멘트를주입함으로써이같은합병증을예방할수있을것으로생각된다. 색인단어 : 풍선척추성형술, 지연성척수압박 약칭제목 : 풍선척추성형술후지연성척수압박 110