Journal of Korean Society of Spine Surgery Union Patterns of Local Autogenous Bone Grafts Using Metal Cages, Allogenic Bone, and Local Autogenous Bone

Journal of Korean Society of Spine Surgery Union Patterns of Local Autogenous Bone Grafts Using Metal Cages, Allogenic Bone, and Local Autogenous Bone Around the Cages During Posterior Lumbar Interbody Fusion: A Retrospective CT Analysis Chan Ho Park, M.D., Eung-Ha Kim, M.D., Ph.D., Keonhee Yun, M.D. J Korean Soc Spine Surg 2017 Jun;24(2):87-94. Originally published online June 30, 2017; https://doi.org/10.4184/jkss.2017.24.2.87 Korean Society of Spine Surgery Asan Medical Center, 88 Olympic-ro 43 Gil, Songpa-gu, Seoul, 05505, Korea Tel: +82-2-483-3413 Fax: +82-2-483-3414 Copyright 2017 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://www.krspine.org/doix.php?id=10.4184/jkss.2017.24.2.87 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. www.krspine.org

Original Article J Korean Soc Spine Surg. 2017 Jun;24(2):87-94. https://doi.org/10.4184/jkss.2017.24.2.87 Union Patterns of Local Autogenous Bone Grafts Using Metal Cages, Allogenic Bone, and Local Autogenous Bone Around the Cages During Posterior Lumbar Interbody Fusion: A Retrospective CT Analysis Chan Ho Park, M.D., Eung-Ha Kim, M.D., Ph.D.*, Keonhee Yun, M.D.* Department of Orthopedic Surgery, Yeungnam University Hospital, Daegu, Korea *Department of Orthopedic Surgery, Soonchunhyang University Bucheon Hospital, Bucheon, Korea Study Design: Retrospective study. Objectives: To conduct an analysis of the union rate and union patterns of local autogenous bone grafts using metal cages, allogenic bone, and local autogenous bone around the cages in posterior lumbar interbody fusion (PLIF). Summary of Literature Review: Local autologous bone grafting using metal cages is regarded as an effective method for union during PLIF without iliac bone harvesting. There are few studies about the additional bone grafting except using metal cages. Materials and Methods: Thirty-nine patients (68 segments) with postoperative computed tomography (CT) results from 6 to 18 months after PLIF were included. We used 2 metal cages filled with local autogenous bone intraoperatively (region C). We also grafted allogenic bone between 2 cages (region A) and local autogenous bone at the side of the cages (region B). Retrospective analyses of the coronal CT sections were performed using the modified Bridwell criteria for assessing the presence of union. A quantitative evaluation was performed using a scoring system that assessed the proportion of radiopaque parts of the union mass. Results: Among the 68 segments, union was observed in 64 segments, resulting in a union rate of 95.6%. The union rates in regions A, B, and C were 86.8%, 89.7%, and 94.1%, respectively. Trabeculation and the quantitative evaluation of union bone showed a statistically significant trend for improvement from regions A to C (p<0.001). Conclusions: In this study, the complementary effect of additional bone grafting other than local bone grafting was not proven, but it was effective in increasing the fusion area at around 90%. Keeping the height of disc space with the cages, additional bone grafting using local autogenous and allogenous bone may be used as an effective method for stable union. Key words: Lumbar spondylosis, Posterior lumbar interbody fusion, Allogenic bone, Local autologous bone, Union rate 후방추체간유합술시골유합을얻기위해제거된추간판공간에자가골, 동종골및인공구조물에이식골을채워서넣은방법들은여러저자들에의해소개되었다. 1-3) 일반적으로자가골은동종골단독보다유합이빠르고견고한유합을얻을수있다는장점이있다. 4,5) 장골능에서채취하는자가장골이식방법은생물학적골형성을통해골유합률을높일수있어선호되는방법이나공여부의출혈및지속적인동통이발생할수있고, 6,7) 골다공증이심한환자의경우충분한양의자가골을얻지못하는경우가있다. 반면몇몇저자들이동종골만을이용하여골이식을하는경우에도자가골에비하여방사선학적, 임상적결과에차이가없다고보고하였고, 7,8) 또한최근보고된체계적문헌고찰에서자 가장골이식과동종골이식간의유합률의비교에있어유의한 차이가없다고보고하였다. 9) 그러나상업화된동결건조동종 Received: February 2, 2017 Revised: February 7, 2017 Accepted: May 30, 2017 Published Online: June 30, 2017 Corresponding author: Eung-Ha Kim, M.D., Ph.D. ORCID ID: 0000-0003-4615-4163 Department of Orthopedic Surgery, Soonchunhyang University Bucheon Hospital, 170 Jomaru-ro, Wonmi-gu, Bucheon, Gyeonggi-do, of Korea TEL: +82-32-621-5259, FAX: +82-32-324-9577 E-mail: eungha@gmail.com Copyright 2017 Korean Society of Spine Surgery Journal of Korean Society of Spine Surgery. www.krspine.org. pissn 2093-4378 eissn 2093-4386 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 87

Chan Ho Park et al Volume 24 Number 2 June 2017 골만사용하는경우골형성능력의부족으로초기골유합의진행속도가느리다고보고되었으며, 10) 후방추체간유합술시행시동일한조건의추체간에서도자가골과동종골의유합양상과골소주의형성에는차이가있을것으로예상된다. 그렇다면장골능에서의골채취로인한부작용과동종골만을이용하는경우의느린유합진행속도를보완하기위한대안으로서후궁절제술을통해얻어진자가국소골을이식하는방법을생각할수있다. 이미 Okuda 등은고령의환자에서도후방추체간유합술시후궁절제술로얻은자가국소골을케이지외측에이식하여만족스러운결과를보고하였다. 11) 그러나자가국소골만을이용하는경우이식골의양이충분하지않아동종골을동시에이식해야할가능성이높다. 골유합의확실성을높이기위해국소골을채운케이지이외의공간에남은국소골과동종골을추가적으로삽입한다면골유합의가능성을높이는효과가있지않을까하는가설이입증된다면추가적인골이식방법이유합을높이는데있어효과적인술식으로사용할수있겠다. 본교실에서는 2008년부터후방장골능에서자가장골의채취없이부분후궁절제술로얻은자가국소골과동결건조동종골을동시에추간판공간에이식함으로써만족스러운방사선학적, 임상적결과를보였다. 이에따라본연구의목적으로는후궁절제술을통해얻은자가국소골을케이지내부에삽입하여이식하는방법과함께케이지이외의공간을구분하여케이지사이에는동종골을채우고케이지외측에는남은자가국소골을다져넣어각부위별로유합률과유합양상을 Computed tomography (CT) 를이용하여후향적으로분석하고자하였다. 대상및방법 1. 연구대상 2009년 1월부터 2014년 11월까지단일술자에의해서후방요추체간유합술을시행한환자중 2년이상추시가가능하였고술후 6개월에서 18개월사이에 CT를촬영한환자를대상으로하였다. 총 39명의환자가포함되었으며, 유합술의범위는 1분절 16명, 2분절 20명, 3분절 4명으로총 68분절이었다. 환자들의성별은남자 15명, 여자 24명이었고, 평균연령은 65.5 세 ( 범위, 51~83세 ) 였다. 환자들의평균찰슨동반상병지수 (Charlson Comorbidity Index) 는 2.9( 범위, 0~9) 였다. 수술후 CT를촬영한기간은평균 11개월이었다. 원인질환은 28례에서척추관협착증, 퇴행성전방전위증이 4예, 인접분절질환이 4 예, 협부형전방전위증 1예, 퇴행성추간판증이 1예, 재발된추간판탈출증이 1예였다. 2. 골이식방법수술시모든분절에서두개의금속케이지 (Neo-IC R square, U & I Corporation, Uijeongbu, Korea) 를이용하였다. 이케이지는전만각이 0도, 4도, 8도세가지의종류가있어수술시분절당요추전만각을회복하고자하는정도에따라케이지를선택하였고, 케이지를삽입후회전시켜전만각을회복하는방식의케이지이다. 부분후궁절제술로얻은자가국소골을조각골로만들어케이지내부에채운후먼저한개의케이지를추간판공간을이분하였을때좌측중심에삽입한후회전시켜고정하였다. 그런다음척추체중심부에동종골조각들을삽입하고우측중심에케이지를삽입하고케이지를추간판공간중심을향하여힘을가한뒤회전시킴으로써케이지사이이식된동종골이압착되어밀도가높아지도록하였다. 그후케이지외측에공간에남은자가국소골을깔때기와막대를이용하여치밀하게다져넣었다. 이처럼골이식을케이지사이동종골이식부 Fig. 1. The method of laminectomy and bone grafting was like as below diagram. (A) Allogenic bone between cages, (B) Local autogenous bone, (C) Local autogenous bone using cages. 88 www.krspine.org

Journal of Korean Society of Spine Surgery Union Pattern of Grafted Bone During Posterior Lumbar Interbody Fusion 위 (A 구역 ), 케이지외측자가국소골이식부위 (B 구역 ), 케이지내부자가국소골이식부위 (C 구역 ) 로나누어시행하였다 (Fig. 1). 케이지외측의자가국소골이식부위는남은국소골을사용하고추가적장골능채취는하지않았다. 케이지삽입과골이식후후방고정을시행하였고, 원주상유합술은시행하지는않았다. 3. 방사선학적평가 2개이상의분절환자의경우방사선학적평가는각각의분절에대하여따로실시하였다. CT 관상면에서 A, B, C 구역을분석하였다. 추체간유합의판단은세가지의골이식구역중어느한부분이라도유합소견을보이는경우로정하였다. 척추체간유합의평가는 modified Bridwell criteria 12) (Grade I, 골가교형성및골소주재형성이되어유합된경우 ; Grade II, 완전히골가교형성및골소주재형성은되지않았으나케이지및이식골상하부척추체와접한부분에방사선투과성 (radiolucency) 이없는경우 ; Grade III, 케이지및이식골상하부척추체와접한부분에명확한방사선투과성 (radiolucency) 이있는경우 ; Grade IV, 명확히유합이되지않은경우 ) 로평가하였다. 유합의정도만이아니라유합골괴의정량적분석을위해 Image J ver. 1.49 K (NIH, Bethesda, MD, USA) 를이용하여방사선투과성 (radiolucent) 부분을 0~80까지의 Hounsfield Unit (HU) 으로설정하여처리한후유합골괴의전체크기와유합골괴내방사선투과성부분을정량적으로측정하였다 (Fig. 2). 전체유합골괴에서투과성부분을뺀유합골괴의비율이 100~75% 의경우 3점, 75~50% 의경우 2점, 50~25% 의경우 1 점, 25% 이하의경우를 0점으로점수화하여분석하였다. 3. 통계분석점수화한순위척도에대한경향분석을위해 Jonckheere- Terpstra test 시행하였고, 유의수준은 0.05로하였다. 13) 결과 1. 골소주형성 (Trabeculation) 골소주형성은 A구역에서 Grade I 10예 (14.7%), Grade II 49예 (72.1%), Grade III 7예 (10.3%), Grade IV 2예 (2.9%) 로나타났다. B 구역에서는 Grade I 28예 (41.2%), Grade II 33 예 (48.5%), Grade III 5예 (7.4%), Grade IV 2예 (2.9%) 로나타났다. C 구역에서는 Grade I 37예 (54.4%), Grade II 27예 (39.7%), Grade III 2예 (2.9%), Grade IV 2예 (2.9%) 로나타났다. Jonckheere-Terpstra test 상유의하게 A에서 C 구역으로갈수록골소주형성이잘되는선형적인경향성이나타났다 (p<0.001) (Table 1, Fig. 3A). Fig. 2. Measurement of radiopaque area in union bone by software program (between 0 to 80 Hounsfield unit). 2. 유합골괴의정량분석 (Quantitative evaluation) Image J를이용한정량분석을점수화한결과는 A구역에서 3점 4예 (4.4%), 2점 35예 (51.5%), 1점 25예 (36.8%), 0점 5예 (7.4%) 로나타났다. B 구역에서는 3점 16예 (23.5%), 2점 38예 (55.9%), 1점 12예 (17.6%), 0점 2예 (2.9%) 로나타났다. C 구역에서는 3점 28예 (41.2%), 2점 29예 (42.6%), 1점 11예 (16.2%), 0점 0예 (0%) 로나타났다. Jonckheere-Terpstra test 상유의하게 A에서 C 구역으로갈수록높은선형적인경향성이나타났다 (p<0.001) (Table 2, Fig. 3B). Table 1. Comparison of trabeculation by Bridwell criteria Grade I Grade II Grade III Grade IV p-value A region 10(14.7) 49(72.1) 7(10.3) 2(2.9) B region 28(41.2) 33(48.5) 5(7.4) 2(2.9) C region 37(54.4) 27(39.7) 2(2.9) 2(2.9) *:All values are described as frequency (%), : p-value was calculated by Jonckneere-Terpstra test (alternative hypothesis; decreasing). <0.001 www.krspine.org 89

Chan Ho Park et al Volume 24 Number 2 June 2017 Table 2. Comparison of density by scoring system 3 2 1 0 p-value A region 3(4.4) 35(51.5) 25(36.8) 5(7.4) B region 16(23.5) 38(55.9) 12(17.6) 2(2.9) C region 28(41.2) 29(42.6) 11(16.2) 0(0) *: All values are described as frequency (%), : p-value was calculated by Jonckneere-Terpstra test (alternative hypothesis; increasing). <0.001 A B Fig. 3. Proportions of the Bridwell of trabeculation (A) and the density scores (B) in each region. 3. 유합률 (Union rate) Bridwell Grade I과 II는유합된것으로간주하였으며, 세개의구역중어느한부분이라도골소주형성되어유합된예는전체 68분절중에 64분절에서관찰되어 94.1% 의높은유합률을보였다. 각구역에서의유합률은 A구역에서 86.8%, B 구역에서 89.7%, C 구역에서 94.1% 로나타났다. 케이지내부자가국소골이유합이안된채로그외의구역에서유합된예는없었다. 고찰 금속케이지를이용한후방추체간유합술은방사선학적, 임상적인치료결과가매우우수한것으로알려져있다. 14) 추간판공간에케이지없이동종골만을이식하여도좋은결과를보인다는보고도있으나, 15) 동종골만을이식한경우수술직후생역학적안정성을충분히얻지못하여이식골붕괴와불유합의발생가능성이있다. 16) 본연구에서두개의금속케이지속의국소자가골은상하추단판과안정적인접촉으로인해유합의가능성이가장높은것으로생각되며, 술후평균 11개월에촬영한 CT상 C구역에서 94.1% 로관찰되었다. A, B 구역에서도유합골의붕괴없이 86.8%, 89.7% 의유합율을보였으나자가국소골이유합이안된채로동종골만이유합된예는없었으므로 동종골이식이전체유합률을향상시키는데기여하지않았다고생각할수있다. 따라서 B구역과 C구역의추가적인골이식이불유합을보완하는지는이연구에서는제시할수없었다. 그러나케이지이외공간의이식골은약 90% 에서골소주형성을보여자가국소골과동종골의추가적이식이추체간의유합골괴의크기를증가시켜케이지에가해지는부하를줄일수있는이점을생각할수있다. 동일하게후궁절제술에서얻은자가국소골을이용했음에도불구하고케이지내부와외측의골이식방법중골소주형성및유합골괴의정량분석모두케이지내부의자가국소골이더우수한것으로나타났다. 이는케이지내부의국소골이상하추단판압박으로인한골전도 (osteoconduction) 가잘일어난것으로생각된다. 또한케이지사이의동종골은최대한압착하여이식하였음에도불구하고골조각상태로삽입하기때문에상하추단판과의접촉이케이지를이용한국소자가골에비해부족하며, 동종골이기때문에골유도능력이부족하여유합률이떨어진것으로판단된다. 케이지외측의국소자가골은깔때기를이용하여치밀하게시행하여추단판과의접촉은양호하나자가국소골이부족한경우충분한양의이식을할수없어유합률이낮을수밖에없는것으로판단된다. B 구역에서자가국소골을깔때기를사용하여치밀하게이식하여상하추단판과접촉이잘되었지만몇례에선자가국소골이부족하여충분히채워지지못하였으며, CT 상골소주형성 90 www.krspine.org

Journal of Korean Society of Spine Surgery Union Pattern of Grafted Bone During Posterior Lumbar Interbody Fusion 이부진한예는이때문인것으로생각된다. CT 상 B 구역에서국소골을충분히다져넣은례로국한하여분석한다면유합률은지금보다높을것으로추정된다. 일반적으로척추유합술후골소주형성은강한고정력을가진구조에의해촉진된다. 17) 이는유한요소법에의한생역학연구에서도알수있듯이, 케이지가삽입된분절에여러방향의부하를가해도케이지는움직임이거의없이안정적으로유지됨으로써골생성에안정적인환경을제공해준다. 18) 후방추체간유합술은최근에거의 2개의케이지와후방나사못고정을시행하는바추간판내안정성은세구역에서비슷하다고생각한다면이식골의종류와이식방법이유합률과유합양상을결정한다고하겠다. 이연구는술후약 1 년에 CT를시행한례에서만분석을시행하였지만장기간추시한경우결과는다를수있다. 인접분절질환등으로술후 2년째촬영한 CT에서이전에관찰되지않았던골소주형성이잘형성되었음을확인할수있었다 (Fig. 4). 이는제한적이지만, 많은연구에서최종추시상에서자가골과동종골의골유합은차이가없다는결과와일치한다고볼수있다. 8,19) 반면, 본연구의증례처럼술후 6~12개월경과시에는골이식방법에따른골소주형성차이가유의하게있는것으로보아케이지내부자가국소골이골소주형성이가장빨리됨을알수있다. 또한케이지내부자가국소골이유합이안된채로케이지외측자가국소골과케이지사이동종골이유합된예가없는것으로보아케이지내부자가국소골에서골소주생성이먼저이루어지면서그이후케이지외측자가국소골, 동종골이식부위로골소주생성이된다고생각할수있겠다. 이점을고려하였을때유합을얻지못한 4예의원인은케이지를통해척추체간충분한안정성을얻지못하면서케이지내부자가국소골에서적절히골소주형성이이루어지지않고케이지외측자가국소골과동종골에서도골소주형성이되지않은것으로생각된다. Ito 등의저자들이보고한다기관연구에서자가장골채취없이자가국소골만을사용한경우와자가장골을동시에이식한경우의유합률이각각 96.3%, 98.3% 유합률의차이가없는것으로보고하였다. 7) 본연구에서의유합률은 94.1% 로, Ito의연구와유사한결과를보여저자들의골이식방법도동등한결과를얻을수있는방법이라할수있겠다. 또한동종골대신수산화인회석이나삼인산칼슘등의골이식확장제사용에대한연구들이보고되고있는데, 20-22) 골이식확장제의단독사용시의유합률은우수하지못한것으로보고되고있다. Tahler 등이보고한연구에서케이지내부에베타-삼인산칼슘만을단독사용하여후방추체간유합술을시행한경우 1년뒤 CT를이용 A B Fig. 4. (A) 77-year-old woman showed the trabeculation of Bridwell grade IV in region A of L4-5 after 12 months of posterior lumbar interbody fusion. (B) After the another 12 months, solid union of Bridwell grade I in region A was obtained. 한유합률이 61.4% 로현저히낮은것으로나타났다. 23) 그러나 수산화인회석을자가국소골과혼합하여사용한연구에서는 유합률이 91.7% 로자가국소골과자가장골의유합률 94.6%, 92.9% 와차이가없다고보고되어, 본연구와유사한유합률을 보였다. 24) 결국골이식확장제들은단독사용은어렵고자가골 과같이혼합하여이식하는경우만족할만한결과를보이고있 어자가골이식이골유합에중요함을알수있다. 25) 이상의논문들의결과에더하여본연구의결과에서보듯이 케이지사이에이식한동종골이술후 1 년간의전체유합률향 상에기여하지못한다는것을볼때동종골과자가골을혼합하 여케이지사이에사용하는것이유합율을높일가능성이있을 것으로보인다. 다만케이지사이공간이넓어국소골이부족한 www.krspine.org 91

Chan Ho Park et al Volume 24 Number 2 June 2017 Fig. 5. Sagittal images also showed the long axis of union bone that had superior tendency of quantitative evaluation from C region to A region. 경우가대부분이어서추가적골채취가필요하다는단점이있겠다. 저자들은케이지에넣고남은자가국소골을좁은케이지외측공간에치밀하게이식하여유합의가능성을높일수있다고생각하였다. 본연구의제한점으로는첫째, 후향적연구로서 CT의촬영시기가 6~18개월로동일하지못하다는점이다. 그러나평균촬영시기는술후 11개월로대부분골유합을얻을수있는시점이므로이로인한오차보다는이식재부위에따른상대적인골유합진행속도의차이를알수있었다. 두번째로 CT 촬영시금속케이지로인한간섭현상을줄이기위한특별한처리를하지않아유합골괴의경계선이정확히관찰되지않을수있어 Image J 를이용한유합골괴의정량적분석이측정자간오차가발생할수있다. 임상적으로유합여부를시상면영상으로판단하기좋고시상면상의분석으로정량적정확성을높일수있으나저자들은비교와분석을용이하게하기위해관상면영상을분석하였다 (Fig. 5). 위와같은제한점에도불구하고본연구의강점으로는자가골과동종골의유합골괴를 CT를이용하여관찰하여유합양상을분석하였고, 유합골괴의정량적인분석을하였다는것이다. 결론 저자들이시행한케이지를이용하여자가국소골이식이외의추가적골이식이전체유합율을높이는보완적효과는입증되지않았으나, 후방추체간유합술후약 1년경과시약 90% 의유합률을보여유합면적을높이는효과가있었다. 또한케이지사이의동종골, 케이지외측자가국소골, 케이지내부의자가국소골로갈수록골소주형성이우수하고유합골괴의질 도양호한것으로나타나, 하나의분절에서골이식방법과골이식재에따라유합률및유합양상의차이가있음을알수있었다. 그러므로케이지를이용하여추간판간격을유지한채로추가적인자가골과동종골이식은안정적인유합을얻기위한효과적인방법으로사용될수있겠다. REFERENCES 1. Pitzen T, Geisler FH, Matthis D, et al. Motion of threaded cages in posterior lumbar interbody fusion. Eur Spine J. 2000;9:571-6. 2. Ma GW. Posterior lumbar interbody fusion with specialized instruments. Clin Orthop Relat Res. 1985:57-63. 3. Brantigan JW, Steffee AD, Geiger JM. A carbon fiber implant to aid interbody lumbar fusion. Mechanical testing. Spine (Phila Pa 1976). 1991;16(Suppl):277-82. 4. Jorgenson SS, Lowe TG, France J, et al. A prospective analysis of autograft versus allograft in posterolateral lumbar fusion in the same patient. A minimum of 1-year follow-up in 144 patients. Spine (Phila Pa 1976). 1994;19:2048-53. 5. An HS, Lynch K, Toth J. Prospective comparison of autograft vs. allograft for adult posterolateral lumbar spine fusion: differences among freeze-dried, frozen, and mixed grafts. J Spin Disord. 1995;8:131-5. 6. Fernyhough JC, Schimandle JJ, Weigel MC, et al. Chronic donor site pain complicating bone graft harvesting from the posterior iliac crest for spinal fusion. Spine (Phila Pa 1976). 1992;17:1474-80. 92 www.krspine.org

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Original Article J Korean Soc Spine Surg. 2017 Jun;24(2):87-94. https://doi.org/10.4184/jkss.2017.24.2.94 후방추체간유합술시금속케이지를이용한자가국소골이식과케이지주변동종골과자가국소골의유합양상 : 전산화단층촬영분석 박찬호 김응하 * 윤건희 * 영남대학교병원정형외과, * 순천향대부천병원정형외과연구계획 : 후향적연구목적 : 후방추체간유합술시금속케이지를이용한자가국소골이식과케이지주변에이식한자가국소골및동종골의유합률및유합양상에대하여분석하고자한다. 선행문헌의요약 : 금속케이지를이용한자가국소골이식은후방추체간유합술시장골능의골채취없이골유합을얻는데효과적인방법으로생각된다. 국소골케이지외추가적골이식이유합율을높이는지에대한연구는별로없다. 대상및방법 : 요추부질환으로후방추체간유합술을시행받은환자중술후 6개월에서 18개월사이에 CT (computed tomography) 를촬영한환자 39 명, 68분절을대상으로하였다. 후방추체간유합술시 2개의금속케이지 (C 구역 ) 에후궁절제술로얻은자가국소골을채운후사용하였다. 두개의케이지사이에는동결건조동종골 (A 구역 ) 을이식하였고, 케이지측면에도자가국소골 (B 구역 ) 을이식하였다. CT 관상면을분석하여케이지내부및주변추체와의골소주형성정도를 modified Bridwell criteria 를이용하여분석하였고, 유합골괴의정량적분석을위해전체크기중방사선비투과성부분의크기를점수화하여분석하였다. 결과 : 전체 68분절중에 64분절에서유합되어 94.1% 의높은유합률을보였으며, A, B, C 구역각각의유합률은 86.8%, 89.7%, 94.1% 로나타났다. 골소주형성과유합골괴의정량적분석모두케이지사이동종골이식부위 (A 구역 ) 에서케이지외측자가국소골이식부위 (B 구역 ), 케이지를내부자가국소골이식부위 (C 구역 ) 로갈수록우수한경향을보였다 (p<0.001). 결론 : 본연구를통해케이지를이용한자가국소골이식이외의추가적골이식이전체유합율을높이는보완적효과는입증되지않았으나 90% 내외에서유합을보여유합면적을높이는효과가있었다. 케이지로추간판간격을유지한채로추가적인자가골과동종골이식은안정적인유합을얻기위한효과적인방법으로사용될수있겠다. 색인단어 : 요추질환, 후방추체간유합술, 동종골, 자가국소골, 유합률 약칭제목 : 후방추체간유합술시이식골의유합양상 접수일 : 2017년 2월 2일 수정일 : 2017년 2월 7일 게재확정일 : 2017년 5월 30일 교신저자 : 김응하 경기도부천시원미구조마루로 170 순천향대부천병원정형외과 TEL: 032-621-5259 FAX: 032-324-9577 E-mail: eungha@gmail.com 94 Copyright 2017 Korean Society of Spine Surgery Journal of Korean Society of Spine Surgery. www.krspine.org. pissn 2093-4378 eissn 2093-4386 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.