untitled

J Korean Assoc Maxillofac Plast Reconstr Surg 2012;34(5):337-342 pissn:1225-4207 eissn: 2233-7296 Case Report 비골을이용한 3 차원적하악골재건시가상모의수술및입체조형기법을이용한골절단가이드의활용 : 증례보고 남웅, Nicholas Makhoul 1, Brent Ward 1, Joseph I. Helman 1, Sean Edwards 1 연세대학교치과대학구강악안면외과학교실, 1 미시건대학교치과대학구강악안면외과학교실 Abstract Virtual Surgical Planning and Stereolithography-guided Osteotomy for 3 Dimensional Mandibular Reconstruction with Free Fibula Osseous Flaps: A Case Report Woong Nam, Nicholas Makhoul 1, Brent Ward 1, Joseph I. Helman 1, Sean Edwards 1 Department of Oral and Maxillofacial Surgery, Yonsei University College of Dentistry, 1 Department of Oral and Maxillofacial Surgery, University of Michigan College of Dentistry The osseous or osteocutaneous free fibula flap has become the gold standard for most mandibular reconstructions because of its favorable osseous characteristics. However, disadvantages, such as the time-consuming reconstructive step, difficulty in performing the osteotomies to precisely recreate the shape of the missing segment of mandible and poor bone-to-bone contact play a role in making the surgeons look for alternative flaps. With the advent of computerized design software, which accurately plans complex 3-dimensional reconstructions, has become a process that is more efficient and precise. However, the ability to transfer the computerized plan into the surgical field with stereolithographic models and guides has been a significant development in advancing reconstruction in the maxillofacial regions. The ability to "pre-plan" the case, mirror and superimpose natural structures into diseased and deformed areas, as well as the ability to reproduce these plans with good surgical precision has decreased overall operative time, and has helped facilitate functional and esthetic reconstruction. We describe a complex case treated with this technique, showing the power and elegance of computer assisted maxillofacial reconstruction from the University of Michigan, Oral and Maxillofacial Surgery. Key words: Virtual surgical planning, Stereolithography, Fibula 원고접수일 2012년 6월 12일, 원고수정일 2012년 7월 31일, 게재확정일 2012년 8월 27일책임저자남웅 (120-752) 서울시서대문구연세로 50, 연세대학교치과대학구강악안면외과학교실 Tel: 02-2228-2971, Fax: 02-2227-8022, E-mail: seanedwa@med.umich.edu 337 RECEIVED June 12, 2012, REVISED July 31, 2012, ACCEPTED August 27, 2012 Correspondence to Woong Nam Department of Oral and Maxillofacial Surgery, Yonsei University College of Dentistry 50, Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea Tel: 82-2-2228-2971, Fax: 82-2-2227-8022, E-mail: seanedwa@med.umich.edu CC 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.

338 남웅 : 가상모의수술및입체조형기법을이용한하악골재건 서론 하악골의재건은미세재건술이도입된이후에도여전히어려운데, 그이유는하악골이기능및하안면부의미적조화측면에있어서아주중요한부분을차지하고있기때문이다 [1-3]. 이러한하악골의재건에있어서그동안다양한방법및재료가이용되어져왔으나 [2,4,5], 최근에는우수한골성특징을가진혈관화유리비골피판이하악골재건에있어일차적으로선택되고있다 [6-8]. 그동안일직선형태로곧은비골피판을하악골의형태에맞도록적합시키려는노력이다방면으로진행되어져왔고 [5,9], 최근에는증강현실 (augmented reality)[10,11] 및컴퓨터를이용한술중네비게이션 (computer-assisted intraoperative navigation) 의도입과 3차원적인술전치료계획의설정 [1,12] 이가능해졌음에도불구하고, 비골피판을이용한하악골의재건은여전히어려운데, 그이유는비골을이용해하악골의형태를잡는것이아직도술자의경험에많이의존하고있고, 골절단면의예측이어렵기때문이다 [2]. 이론적으로, 수술시이용되는금속재건판의형태는결국원래의하악골또는컴퓨터상에서재건한하악골의바깥쪽피질골을따르게되는데, 이러한이유로하악골재건시, 특히중심부에서는원래의형태보다항상작아지게되며, 골과골사이의긴밀한접촉 (bone-to-bone contact) 도얻기힘들다. 게다가스크류를조이게되면각골편들이바깥쪽으로움직이게되어서로간에멀어지는결과를초래하기도한다 [13]. 이외에긴수술시간역시이러한문제를더욱어렵게하는요소로생각되고있다 [2]. 본논문에서는이러한단점을극복하기위해보다정교하게조절된가상모의수술계획 (virtual surgical planning) 으로술전에 3차원적인수술계획을세우고, 술중입체조형물과골절단가이드를통해보다향상된골과골사이의접촉이가능하도록하는입체조형물을이용한골절단기법 (stereolithography-guided osteotomy) 으로성공적으로치유된미시건치과대학구강악안면외과환자의증례와그기법들을소개하고자한다. 증례보고 38세여자환자가자동차사고로양측하악골골절이되어내원하였다. 구강내는무치악이었으며, Crohn's disease 병력과만성스테로이드복용, 심한하악골위축을동반하고있었다. 따라서초기치료는관혈적정복술및내고정술로이루어졌다. 술후골수염이동반되었으며, 장기간의항생제치료및외부고정장치 (external fixator) 가장착되었다. 골수염이완치된후하악골재건을위해본과에다시내원하였다 (Fig. 1). 안면우측에장착되었던외부고정장치 (external fixator) 가실패하면서하악골의형태가소실되었다. 미시건대학교구강악안면외과수술팀은다음과같은과정으로치료를진행하였다. 우선환자의두경부수술부위와비골부위의컴퓨터단층촬영 (computed tomography, CT) 을시행한후, Medical Modeling Inc. 측에 CT 이미지를전송, 3차원적인이미지로변환하였다. 수술팀은컴퓨터상에서 Simplant 프로그램을이용, 3차원적인가상모의수술 (virtual surgery) 을시행하면서골절단부를결정하고, 비골이미지를중첩시켜재건할하악골 (neomandible) 을설계하였다. 이과정에서수술팀은본환자하안면부의수직, 관상및시상면을재설정하였으며, 과두와하악지의생리적위치도재설정하였다 (Fig. 2). 상기한과정을모두시행한후파일의형태로전송, 입체조형기법 (stereolithographic manufacturing) 으로재현된두개모형 (skull) 을받았고, 부가적으로받은비골절단가이드 (fibular cutting guide) 와비골로재건된하악골모형에술중사용할금속재건판을미리적합 (precontouring) 해보았다. 2팀동시수술 (2-team approach) 에의해안면부수술이진행되는동안재건을담당한수술팀이혈관화유리비골피판의거상과비골절단가이드 (fibular cutting guide) (Fig. 3) 를이용한정교한골절단까지모두완료한후피판을안면으로옮겨미리적합된금속재건판에피판을고정하고, 미세혈관문합을시행하였다. 본환자의경우혈관화비골피판을이용하여한쪽하악각에서부터반대쪽하악각 Fig. 1. (A) Frontal view. (B) Lateral view. A 38-year-old woman with mandibular fracture combined with edentulism and atrophic mandible. She also had Crohn's disease and chronic steroids medication. Initial treatment was comprised of open reduction and internal fixation. However, external fixator was attached and long-term antibiotics therapy was done due to postoperative osteomyelitis. Rightside external fixator was lost and virtual surgical planning and stereolithography-guided osteotomy for 3 dimensional mandibular reconstruction with free fibula osseous flaps was initiated. J Korean Assoc Maxillofac Plast Reconstr Surg

Woong Nam: VSP for Mandibular Reconstruction 339 Fig. 2. (A) Three-dimensional recontruction of high-reslolution computed tomography scan of craniofacial skeleton. (B) Plate adapted to proposed neomandible. (C) Planning of fibular osteotomies. 술 후 컴퓨터단층촬영(CT)과 파노라마사진(pantomogram)에서 모두 술 전 수술계획과 동일한 결과를 보여주고 있으며(Fig. 5, 6), 현재 의치를 이용한 구강내 치료를 위해 내원중이며 계속적인 경과관찰 중에 있다. 고 찰 컴퓨터를 이용한 가상모의수술 및 입체조형물을 이용한 3차원 적 하악골재건기법(virtual surgical planning and stereolithography-guided osteotomy for 3 dimensional manfig. 3. Fibular cutting guide. dibular reconstruction)은 다음의 4가지 단계로 이루어진다. 즉, 술 전 계획단계(planning Phase), 모델제작단계(modeling 까지 재건하였고, 잔존하던 전치부 골편은 비골 위쪽으로 고정하여 phase), 수술재건단계(surgical phase), 그리고 마지막 술 후 전방 비골피판의 높이를 증가시켰으며, 앞으로의 구강내 치료를 평가단계(evaluation phase)[2,14]. 2009년 Hirsch 등[2]은 술 위한 전정부의 형태와 깊이를 유지하기 위해 보존하였다(Fig. 4). 후 평가단계(evaluation phase)를 포함시키지 않았지만, 2012년 술 후 양호한 경과를 보였으며, 술 후 10일째 퇴원하였다. Levine 등[14]은 환자에게 이용된 이러한 기법들을 평가하고 술 Vol. 34 No. 5, September 2012

340 남웅 : 가상모의수술및입체조형기법을이용한하악골재건 Fig. 4. (A) Stereolithographic model of neomandible and preadapted plate. (B) Fibula free flap is harvested while the flap continues to be perfused and shaped according to the length of the template. (C) Plate fixed to residual mandible and the pre-shaped fibula flap is then fixed to the plate. (D) Revascularization of free fibula flap. 후결과를향상시키기위해서술후평가단계 (evaluation phase) 를포함시켰고, 평가결과수술의정확도는 1 5 mm 이내로정확하고우수하였다고보고하였다. 특히이러한기법은혈관화유리비골피판을이용한하악골의재건에특히유용한데, Hidalgo 등의초기임상발표 [6-8] 이후하악골재건의표준이된혈관화유리비골피판은 2팀동시수술이가능하고, 비교적직경이큰혈관과다수의골절단이가능케하는혈관계, 그리고전하악골재건 (near-total mandibular reconstruction) 이가능한충분한길이등의장점을가진동시에, 그동안하악골재건을위한정확한골절단및접합이어려워수술시간이길어졌던단점등을충분히보완할수있었기때문이다. 술전계획단계 (planning phase) 는수술팀과소프트웨어제작기술팀과의원활한의사소통을바탕으로하악골절제의범위를결정하고, 남아있는하악골과두개안면골격과의관계에맞도록비골을위치시키는과정, 즉가상모의수술 (virtual surgery) 과정을포함한다. 가상골절단 (virtual osteotomies) 을통해술후 bony union을위한최적의골침착이가능하도록하고술중비골을위치시키고고정하는과정을용이하도록한다. 모델제작단계 (modeling phase) 는술전계획단계에서이루어진가상모의수술 (virtual surgery) 의자료를바탕으로, 입체조형물 (stereolithographic model) 을제작하는데, 이는수련의나학생들에게골절제범위와그질환에대한교육적인정보도제공해줄뿐만아니라, 골절단가이드 (cutting guide) 를함께위치시켜봄으로써술중정확한골절단위치에대한정보도제공해준다. 또한가상모의수술시위치시킨비골상에재건판을미리적합시켜수술 에이용함으로써수술시간을줄일수있고, 혈관화유리비골재건술시가장시간이많이소요되는비골절단과정을단축시킬수있다. 이러한모델제작과정이없는 1세대의, 컴퓨터를이용한가상모의수술 (virtual surgery) 이나술중네비게이션 (intraoperative navigation) 기법들은술자에게시각적인정보만을제공할뿐이지만, 2세대라불리는신속조형기법 (rapid prototyping technique) 이나 3차원적인입체조형물의제작 (3D stereolithography) 기법은술자에게부가적인 ' 촉각 (haptic)' 정보까지제공해주어수술시매우편리하다. 수술재건단계 (surgical phase) 에서는주로, 실제적인하악골의절제와기존에이용되던 Marchetti 등 [5] 의방법을이용해상하악관계를일시적으로유지시킨후미리적합시켰던재건판을하악골에부착시킨다. 또한모델제작단계 (modeling phase) 에서준비되었던골절단가이드 (cutting guide) 를이용하여비골을절단하면수술시간을단축시킬수있다. 이후과정은통상적인미세혈관문합수술및혈관화유리비골피판의고정과정, 봉합등을포함한다. 마지막으로술후평가단계 (evaluation phase) 를통해이전의모든단계를재점검하고수술의정확도를평가, 수술기법을개선하도록한다. 이러한기법은현재양성, 악성종양수술후의두경부재건뿐만아니라, 악교정수술, 악안면외상, 측두하악관절및두개저수술등다양한방면으로응용되고있는데 [14], 본논문에서소개된환자는전신적인만성질환과위축된하악골의골절, 골수염및장기간의항생제복용등의복합적인문제가있었던경우로, 치료 J Korean Assoc Maxillofac Plast Reconstr Surg

Woong Nam: VSP for Mandibular Reconstruction 341 Fig. 5. Postoperative view. (A) Frontal, (B) lateral, (C) & (D) 3-dimensional tomographic images. Fig. 6. Posteoperative panorex view. 계획으로서는골절부위를안정시키고, 골수염이동반된창상에혈류를공급해줌으로써골절부위로골형성세포를유도해주어야하는어려움이있었다. 만일, 결손부위가작은것만고려하여비혈관화자가골이식만시행하였다면, 불량한이식골주위환경으로인해이식된골이괴사되었거나불량한술후결과를초래하였을것으로생각한다. 하지만, 이러한증례에앞서언급한기법들을적용함으로써환자와술자모두만족스러운술후결과를얻을수있었으며, 수술시간또한크게단축할수있었다. 본증례에서살펴본바와같이컴퓨터를이용한가상모의수술및입체조형물에의한 3차원적하악골재건기법 (virtual surgical planning and sterelithography-guided osteotomy for 3 dimensional mandibular reconstruction) 은비교적최근에이르러서야활발히사용되기시작했으며, Hirsch 등 [2] 은이기법의또다른장점들을다음과같이기술하였다. 첫째로, 실제와같은크기로제작된모델을이용함으로써술전에이공 (mental foramen) 과같은해부학적중요구조물들을고려한최적의절제범위의설정이가능하다는점, 두번째로, 술전에가상수술을통해비골로새롭게만들어진하악골 (planned neomandible model) 상에재건판을미리적합 (premolded) 해봄으로써수술시간을단축시킬수있다는점, 실제로재건팀이혈관화유리비골피판을거상하는동안수련의들이수술에사용될재건판을제작된모델에적합시킬수있었다. 마지막으로환자들에게현재의문제점과재건의어려움을설명하고이해시키는데큰도움을줄수있었다는점, 반면비교적높은비용이든다는점과술중절제범위가달라질경우에신속하게변경할수없다는점은이기법의극복해야할단점으로생각되었으며, 차후술중네비게이션기법의도입 [10,15] 과역시절제범위가달라질경우를대비한술중모델제작기법의개발등이보다나은술후결과를위해반드시필요할것으로생각하였다. Vol. 34 No. 5, September 2012

342 남웅 : 가상모의수술및입체조형기법을이용한하악골재건 References 1. Hallermann W, Olsen S, Bardyn T, Taghizadeh F, Banic A, Iizuka T. A new method for computer-aided operation planning for extensive mandibular reconstruction. Plast Reconstr Surg 2006;117:2431-7. 2. Hirsch DL, Garfein ES, Christensen AM, Weimer KA, Saddeh PB, Levine JP. Use of computer-aided design and computer-aided manufacturing to produce orthognathically ideal surgical outcomes: a paradigm shift in head and neck reconstruction. J Oral Maxillofac Surg 2009;67:2115-22. 3. Sharaf B, Levine JP, Hirsch DL, Bastidas JA, Schiff BA, Garfein ES. Importance of computer-aided design and manufacturing technology in the multidisciplinary approach to head and neck reconstruction. J Craniofac Surg 2010;21: 1277-80. 4. Pogrel MA, Podlesh S, Anthony JP, Alexander J. A comparison of vascularized and nonvascularized bone grafts for reconstruction of mandibular continuity defects. J Oral Maxillofac Surg 1997;55:1200-6. 5. Marchetti C, Bianchi A, Mazzoni S, Cipriani R, Campobassi A. Oromandibular reconstruction using a fibula osteocutaneous free flap: four different "preplating" techniques. Plast Reconstr Surg 2006;118:643-51. 6. Hidalgo DA, Pusic AL. Free-flap mandibular reconstruction: a 10-year follow-up study. Plast Reconstr Surg 2002;110: 438-49. 7. Cordeiro PG, Disa JJ, Hidalgo DA, Hu QY. Reconstruction of the mandible with osseous free flaps: a 10-year experience with 150 consecutive patients. Plast Reconstr Surg 1999; 104:1314-20. 8. Hidalgo DA. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg 1989;84:71-9. 9. Wang TH, Tseng CS, Hsieh CY, et al. Using computer-aided design paper model for mandibular reconstruction: a preliminary report. J Oral Maxillofac Surg 2009;67:2534-40. 10. Ewers R, Schicho K. Augmented reality telenavigation in cranio maxillofacial oral surgery. Stud Health Technol Inform 2009;150:24-5. 11. Juergens P, Krol Z, Zeilhofer HF, et al. Computer simulation and rapid prototyping for the reconstruction of the mandible. J Oral Maxillofac Surg 2009;67:2167-70. 12. Rana M, Essig H, Eckardt AM, et al. Advances and innovations in computer-assisted head and neck oncologic surgery. J Craniofac Surg 2012;23:272-8. 13. Leiggener C, Messo E, Thor A, Zeilhofer HF, Hirsch JM. A selective laser sintering guide for transferring a virtual plan to real time surgery in composite mandibular reconstruction with free fibula osseous flaps. Int J Oral Maxillofac Surg 2009;38:187-92. 14. Levine JP, Patel A, Saadeh PB, Hirsch DL. Computer-aided design and manufacturing in craniomaxillofacial surgery: the new state of the art. J Craniofac Surg 2012;23:288-93. 15. Ewers R, Schicho K, Undt G, et al. Basic research and 12 years of clinical experience in computer-assisted navigation technology: a review. Int J Oral Maxillofac Surg 2005;34:1-8. J Korean Assoc Maxillofac Plast Reconstr Surg