Journal of Korean Society of Spine Surgery Congenital Hypoplasia of the Posterior Arch of the Atlas Associated with a Fracture of the Odontoid Process - A Case Report - Sung Kyun Oh, M.D., Seung Bin Lee, M.D. J Korean Soc Spine Surg 2012 Jun;19(2):64-67. Originally published online June 30, 2012; http://dx.doi.org/10.4184/jkss.2012.19.2.64 Korean Society of Spine Surgery Department of Orthopedic Surgery, Inha University School of Medicine #7-206, 3rd ST. Sinheung-Dong, Jung-Gu, Incheon, 400-711, Korea Tel: 82-32-890-3044 Fax: 82-32-890-3467 Copyright 2011 Korean Society of Spine 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.2012.19.2.64 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.
Case Report pissn 2093-4378 eissn 2093-4386 J Korean Soc Spine Surg. 2012 Jun;19(2):64-67. http://dx.doi.org/10.4184/jkss.2012.19.2.64 Congenital Hypoplasia of the Posterior Arch of the Atlas Associated with a Fracture of the Odontoid Process - A Case Report - Sung Kyun Oh, M.D., Seung Bin Lee, M.D. Department of Orthopedic Surgery, Wonkwang University, Iksan, Korea Institute of Wonkwang Medical Science, Iksan, Korea Study Design: Case report. Objectives: To report a rare posterior arch hypoplasia of the atlas and review the clinical significance. Summary of Literature Review: Congenital hypoplasia of posterior arch of the atlas is uncommon. In particular, the combined fracture of the odontoid process has not been reported. Material and Methods: A 56-year-old man developed severe neck pain after a traffic accident. Cervical CT scan revealed a fracture of the odontoid process and hypoplasia of posterior arch of the atlas. Results: Bony union was achieved after halo vest immobilization for three months. Conclusions: Hypoplasia of posterior arch of the atlas is determined incidentally in asymptomatic patients. However, the patients should be evaluated in detail with a 3D CT and MRI to avoid a misinterpretation as fracture, instability or misdiagnosis. Key Words: Atlas, Hypoplasia, Congenital, Anomaly, Dens fracutre 서론 제 1경추후궁의기형은보통경부통증이나외상후검사중우연히발견되는경우가많고빈도역시전체인구중 0.95% 로드물게보이는양성기형으로알려져있다. 1,2) 하지만일부형태의경우골절과혼동가능성이있고또한불안정성이동반된형태의경우작은외상으로도신경학적증세를보일수있으므로그중요성에대해서는간과할수없다. 저자들은이전에보고된바없는제 2경추치상돌기골절과동반된제 1경추후궁의저형성기형을가진환자를치료하였기에보고하고자한다. 증례보고 교통사고후발생한경부통과우측슬관절의동통및부종을주소로 56세남자환자가응급실을통해입원하였다. 환자의단순방사선소견상우측슬관절고원부의골절과함께제 2경추의치돌기골절이의심되었다. 환자의과거력상이전에경부통은없었고고혈압외에특이질환이나타기형은없었으며신경학적검사상에서도이상소견은없었다. 경부 CT 검사상치돌기골절은치돌기와추체사이의골절로 D Alonzo 분류제 2형에해당되었고제1 경추의일측후궁결손과결손측의제2경추척추경골절도동반되어있었다 (Fig 1). 3-D 재건 CT 의경우추 가적으로후궁결손과골절부위의입체적인조망이가능하였고 (Fig 2A), 추가적으로시행한 MRI 상척수의이상소견은보이지 않았고제 1 경추횡인대도관찰할수있었다 (Fig 3). 치돌기골절 의경우 D Alonzo 분류제 2 형에해당되었지만측방상에서전 위가거의없고각변형도보이지않아윤조끼보조기를이용해 고정하였으며, 3 개월후골절부위의유합을추시 CT 상확인할 수있었다 (Fig 2B). 환자의외래추시상 1 년후경추운동범위는 정상으로예전직업과활동으로복귀한상태였다. Received: September 15, 2011 Revised: January 25, 2012 Accepted: February 15, 2012 Published Online: June 30, 2012 Corresponding author: Sung Kyun Oh, M.D. Department of Orthopedic Surgery, School of Medicine, Wonkwang University Sanbon Hospital, Sanbondong, Gunpo city, Gyeongido, Korea TEL: 82-31-390-2224, FAX: 82-31-390-2244 E-mail: niceo@hanmail.net 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. This paper was supported by Wonkwang university in 2012 64 Copyright 2012 Korean Society of Spine Surgery
Journal of Korean Society of Spine Surgery Hypoplasia of the Posterior Arch of the Atlas 고찰 제 2경추치돌기골절의경우 Anderson 과 D Alonzo 의제2 형의치료에대해서는아직도논란이있다. 비수술적인방법으로는불유합의가능성이높기때문에처음부터수술을시행해야한다는의견과전위와각변형이경미한경우윤조끼고정으로치료하면 87-93% 의유합율을보이므로보전적치료에도골유합소견이없는경우에만시행하는것이좋다는의견도있다. 3,4) Ballad 등은측방상에서 5mm 이하의전위와 10도이하의각변형을보이는경우윤조기보조기로고정하도록하며그이상의전위나각변형시에는윤견인으로정복한후수술을시행할것 을권유하고있다. 4) 본환자의경우도전위가거의없고각변형도없어윤조끼보조기로치료하기로하였다. 제 1경추의경우골화발달과정상양측괴의골화중심이후궁으로의골화를진행해출생시거의연골로는유합이되지만실제 3-5살경에야완전한골화된후궁을완성하게된다. 따라서이골화과정의문제가후궁저형성의원인일수있다. 특히골화중심의결함보다는후궁의연골화과정 (cartilage preformation) 의결함을시사하는수술중혹은부검과정의소견이제시된바있다. 5,6) 또한제1경추후궁저형성은성선이형성증, Klippel-Feil 증후군,Arnold-Chiary 기형, 터너혹은다운증후군과연관된다고알려져있다. 2,5,7) Fig. 1. (A C) CT scan shows odontoid process fracture and unilateral defect in posterior arch of the atlas. Fig. 2. Three dimensional reconstructions CT give an additional perspective (A) and (B) After 3 months, union was achieved. 65
Sung Kyun Oh et al Volume 19 Number 2 June 2012 Fig. 3. Magnetic resonance imaging of the cervical spine. T2-weighted sagittal view (A) show no spinal cord lesion and Axial T2 weighted image (B) show the intact transverse atlantoaxial ligament. Fig. 4. Clssification of posterior arch hypoplasia of the atlas. 1) Type A: Failure of posterior midline fusion of the two hemiarches.type B: Unilateral defect. Type C: Bilateral defect. Type D: Absence of posterior arch, with persistent posterior tubercle. Type E: Absence of the entire arch, including the tubercle. 제 1경추후궁저형성은보고자에따라다르지만후궁저형성만보이는경우전체인구의 1.5% 에서 5% 에서보일수있다 1,7) 고하며한국인에서의빈도는 1153례의 CT분석결과 11례로 0.95% 로좀더낮은빈도로보고된바있다. 2) 또한전궁결손의경우더욱낮은 0.1% 의빈도로보일수있다고보고되고있으며대부분후궁저형성과동반되어있다고알려져있다. 8) 1994 년 Currarino 등 1) 은제 1경추후궁저형성을형태에따라 5개의아형으로분류하였다 (Fig 4). 이중가장흔한 A 형의경우인구의 4% 에서보일수있다고하였으나나머지아형의경우 0.69% 로비교적드문것으로알려져있다. 1) 본증례의경우일측후궁의결손을보이는 B형에해당된다. 제 1경추후궁저형성의경우 3가지임상적의의를고려할수있다. 첫째대부분이우연히검사중발견되는무증상의양성병변이라는점이며증상을보이는증례는거의없으나 Currarino 분류의 C나 D형의경우후방결절이치상돌기사이에척수신경을자극하여소위척수충돌 (neural impinge) 을일으켜척수증의원인이될수있다고보고되었다. 5,6) 따라서척수증이나두통과경추통을호소하는 C나 D형의경우후방결절의절제가고려될수있다. 5-7) 둘째로 E형과같은후궁전체의결손을보이는경우경추1-2 번불안정성에의한증세가있을수있으므로 MRI검사를통해환추횡인대 (transverse atlantoaxial ligament) 의존재를확인하여안정성에대한검사가필요할수있다는것이다. 5,7,9) 본 66
Journal of Korean Society of Spine Surgery Hypoplasia of the Posterior Arch of the Atlas 환자의경우도자기공명검사를통해환추횡인대의건전함을확인할수있었고척수공동 (syrinx) 등의척수내병변도관찰되지않았다. 셋째로골절과의감별이필요하다는점이다. 후궁결손의경우는물론전방결손의경우도마찬가지이나외상후발견된경우 Jefferson 골절과의감별이필요할수도있으며이경우 CT검사를통한골절선의경화유무나연부조직부종유무를통해감별이필요하며단순 CT검사의경우제1경추경부기저부에위치하여경부전만에따라축상면에서일부만조영될수있으므로특히 3차원 CT의경우감별및진단에많은도움을준다. 8,9) 결론 치돌기골절과동반된환추후궁결손을보이는환자에대해윤조끼보조기를이용해대증적으로치료하여골유합을얻었다. 이들환자의경우 3차원 CT 영상과 MRI는진단및감별에필수적이며임상적으로양성병변이지만척수증을보일수있는아형이있으므로이를고려하여치료해야한다. REFERENCES 1. Currarino G, Rollins N, Diehl JT. Congenital defects of the posterior arch of the atlas: a report of seven cases including an affected mother and son. AJNR Am J Neuroradiol. 1994;15:249-54. 2. Kwon JK, Kim MS, Lee GJ. The incidence and clinical implications of congenital defects of atlantal arch. J Korean Neurosurg Soc. 2009;46:522-7. 3. Denaro V,Papalia R,Di Martino A,Denaro L,Maffuli N. The best surgical treatment for type Ⅱfractures of the dens is still controversial. Clin Orthop Relat Res. 2011;469:742-50. 4. Ballard WT,Clark CR.Fracture of Dens.(in Clark CR ed. The cervical spine 3rd ed.philadelphia,lippincott-raven:1998.415-27. 5. Klimo P, Jr., Blumenthal DT, Couldwell WT. Congenital partial aplasia of the posterior arch of the atlas causing myelopathy: case report and review of the literature. Spine (Phila Pa 1976). 2003;28:E224-8. 6. Richardson EG, Boone SC, Reid RL. Intermittent quadriparesis associated with a congenital anomaly of the posterior arch of the atlas. Case report. J Bone Joint Surg Am. 1975;57:853-4. 7. Sabuncuoglu H, Ozdogan S, Karadag D, et al. Congenital hypoplasia of the posterior arch of the atlas: case report and extensive review of the literature. Turk Neurosurg. 2011;21:97-103. 8. Park JS, Eun JP, Lee HO. Anteroposterior spondyloschisis of atlas with bilateral cleft defect of posterior arch: a case report. Spine (Phila Pa 1976). 2011;36:E144-7. 9. Corominas L, Masrouha KZ. Congenital absence of the posterior arch of the atlas associated with a fracture of the anterior arch. J Bone Joint Surg Br. 2010;92:1300-2. 제 1 경추후궁기형과동반된치돌기골절 오성균 이승빈원광대학교의과대학정형외과학교실 ^ 원광의과학연구소 연구계획 : 증례보고목적 : 드문제 1경추후궁기형에대해보고하고임상적의의에대해기술하고자한다. 선행문헌의요약 : 제 1경추후궁저형성의경우우연히발견되는양성기형으로알려져있으나외상후제 2경추치돌기골절과동반된경우는보고된바없다. 대상및방법 : 교통사고후발생한경부통으로응급실방문한 56세남자환자의방사선학적검사상제 1경추후궁의일측결손과제 2경추치돌기골절이진단되었다. 결과 : 치돌기골절부위의전위와각변형이없어윤조끼보조기로 3개월간고정하여완전한골유합을얻을수있었다. 결론 : 제 1경추후궁저형성의경우무증상환자에서우연히발견될수있으나정확한아형의분류및진단을위해 3-D CT 와 MRI 검사가필요하다. 색인단어 : 제 1 경추, 저형성, 선청성, 기형, 치돌기골절 약칭제목 : 환추후궁결손 67