ORIGINAL ARTICLE pissn 2234-778X eissn 2234-5248 J Minim Invasive Surg 2015;18(4):106-112 Journal of Minimally Invasive Surgery 보조기구를이용한단일공복강경하담낭절제술 온진석, 정해일, 배상호, 백무준, 이문수, 김창호 순천향대학교의과대학천안병원외과학교실 Jin Seok Ohn, M.D., Hae Il Jung, M.D., Sang Ho Bae, M.D., Ph.D., Moo-Jun Baek, M.D., Ph.D., Moon Soo Lee, M.D., Ph.D., Chang Ho Kim, M.D., Ph.D. Department of Surgery, Soonchunhyang University Cheonan Hospital, Cheonan, Korea Purpose: Currently, single port laparoscopic cholecystectomy (SLC) is gradually being expanded. However, its operative time and complications are reportedly variable according to the surgeon s expertise and experience. In order to overcome these problems, we introduced surgical methods using a 2 mm sized auxiliary device (NELIS, Korea) in cholecystectomy. Methods: Between March 2010 and October 2010, laparoscopic cholecystectomy was performed in 53 patients for non-inflammatory gallbladder stones or gallbladder polyps based on the computed tomography findings. Fourteen of 53 consecutive patients underwent SLC and others underwent CLC. The patient`s clinical characteristics and operative results were evaluated retrospectively. Results: Comparison of clinical characteristics between SLC and CLC groups indicated that the SLC group included younger patients (p=0.008), however other characteristics (sex, mean body index, and previous abdominal operation history) were not significantly different. Operative outcomesparameters including the intensity of postoperative pain, rate of wound complication, and postoperative hospital stay did not differ significantly between the 2 groups. Operative time of the SLC group was longer than that of the CLC group (p=0.002). However, the operative time was decreased according to the increasing SLC cases. By 3 months, patients in the SLC group reported significantly better cosmesis (p=0.036). Conclusion: SLC with an auxiliary device (2 mm, Hold port, NELIS) is technically feasible and might be an alternative method for obtaining a critical view of safety and cosmetic results. Received June 24, 2015 Revised September 7, 2015 Accepted October 5, 2015 Corresponding author Sang Ho Bae Department of Surgery, Soonchunhyang University Cheonan Hospital, 31 Soonchunhyang 6gil, Dongnam-gu, Cheonan 31151, Korea Tel: +82-41-570-3636 Fax: +82-41-571-0129 E-mail: bestoperator@schmc.ac.kr Keywords: Gallbladder, Cholecystectomy, Laparoscopic 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. Copyright 2015 The Journal of Minimally Invasive Surgery. All rights reserved. 서론 1985 년 Eric Muhe 에의해최초로소개된복강경담낭절제 술은국내에는 1990 년대초에처음으로도입되었으며, 이후세 계적으로널리시행되며꾸준히발전을거듭하여현재는담낭절제의표준수술법으로자리잡게되었다. 1 지난 20년간수술법및복강경장비의비약적인발전과더불어여러외과의들에의해투관침숫자를줄이려는노력이있었다. 2,3 단일공복강경하 Journal of Minimally Invasive Surgery Vol.18, No.4, 2015 http://dx.doi.org/10.7602/jmis.2015.18.4.106
107 담낭절제술 (single port laparoscopic cholecystectomy, SLC) 의경우 1997 년에 Navarra et al. 4 의해최초로시행되었으며, 이후여러연구를통해임상적유용성과안정성, 미용적결과의향상이보고되고있다. 5-7 하지만기구의숙달정도와집도하는외과의의축적된경험의정도에따라수술시간과합병증이다양하게보고되고있고, 일반적으로시행되고있는 3공또는 4공복강경담낭절제술 (conventional laparoscopic cholecystectomy, CLC) 에비해기술적인어려움이있어아직까지는제한된경우에만시행되고있다. 8 본연구에서는이러한기술적인문제를극복하고자보조기구인직경 2 mm Hold port (NELIS, Korea) 를이용하여 SLC 를시행하였으며, CLC와비교를통해이방법의기술적인적합성과수술방법및수술전후결과에대해소개를하고자한다. 대상및방법 2010 년 3월에서 2010 년 10 월까지순천향대학교천안병원에서양성담낭질환으로 150 예의복강경담낭절제술이시행되었다. 이중수술전영상단층촬영의결과에따라담낭농흉, 총담관석, 급성담낭염, 담낭암이의심되는환자들과미국마취협회 (ASA) 기준신체점수 3, 4점인고위험군을제외한 53 명의환자를대상으로, 보조기구를이용한 SLC 를받은 14 명의환자군과 CLC를받은 39명의환자의의무기록을참조하여후향적으로분석하였다. 수술은일반적인담낭절제술경험이 200예이상인단일외과의에의하여시행되었고, 수술전모든환자에게충분히고지를하여동의를한환자에게서시행되었고연구윤리심의위원회의승인을받았다 (OOOLA 201506008). 수술방법 scalpel (Ethicon EndoSurgery, Cincinnati, OH, United States), Suction-Hook bovies (Endopath Probe, Ethicon, USA) 및 Roticulator Endo Dissect (Covidien, Mansfield, MA, USA) 를이용하여담낭관과담낭동맥을박리하여노출시키고각각클립을이용하여결찰하고절단하였다. 필요에따라서는 1개의 Hold port 를추가로넣어담낭팽대부를잡아좌우로견인하면서 Calot 삼각의시야를확보하였다 (Fig. 1B). 간으로부터담낭을박리하고복강외로꺼내기전에세심한지혈을시행하였고, 수술중담즙유출이있었던경우선택적으로배액관을삽입하였다. 배액관은 Hold port 크기에맞게 2 mm 직경의배액관을제작하여사용하였고수술종료시점에서 Hold port 를제거할때배액관을잡고나올수있게하였다. 담낭은복강경용비닐백 (Lapbag, Sejong Medical Co., Ltd., Paju, South Korea) 에넣어서복강외로꺼내고복벽과피하층을각각 Safil R 1-0 (B. Braun, Melsungen AG, German) 과 Monosyn R 5-0 (B. Braun, Melsungen AG, German) 으로단속봉합을시행하였고 Hold port site 는봉합하지않고 steri strip 을적용하였다. A 환자는전신마취하에머리와우측편이올라간자세를취하였다. 집도의는환자의좌측에위치하고, 제1 보조의는환자의우측에위치하여변형된보조기구를통해담낭기저부를견인하며, 제2 보조의는집도의의좌측에위치하여복강경카메라를조정하였다. 배꼽을관통하여수직으로 2 cm 가량의절개창을가하고단일통로다투관침기구인 SILS port (Covidien, Inc., Norwalk, CT) 를넣었다. 30 o rigid 10 mm 카메라를 (Karl Storz, Tuttlingen, Germany) 사용하여복강내유착및염증유무를확인하고담낭기저부를견인을할경우위치하는곳인환자의우측상복부늑골직하방에 2 mm 절개를가하여보조기구 Hold port (NELIS, Korea) 를삽입하였다. 담낭기저부를잡아환자의머리쪽으로견인하였고 (Fig. 1A), Harmonic Fig. 1. (A) First, hold the fundus of gallbladder with a Hold port for the cephalad retraction of the gallbladder. (B) Insert another Hold port and hold the infundibular portion of the gallbladder for the bi-directional traction. B www.e-jmis.org
108 Jin Seok Ohn et al. 보조기구 (Hold port) 의구조와사용법 Hold port 는올가미몸통 (snare body, a), 지침 (guide needle, b), 직경 2 mm 의본체 (main body, c) 로구성되었다 (Fig. 2A). 올 가미는강선으로제작되어크기의변동에도타원형고리를형 성할수있는충분한탄성이있었다. 복부에삽입하는방법은 11 번 mes 로피부에 2 mm 절개창을가하고본체에지침을결합 하여복강내로넣은후, 지침을제거하고, 올가미몸통을본체 에밀어넣어손잡이를앞뒤로조정하여올가미크기를조절하 여사용하였다. 손잡이에는걸림장치를두어원하는크기로고 정될수있도록제작되었다 (Fig. 2B). 수술후통증의측정과조절및미용적측면에서환자만족도 수술후통증을조절하기위하여 Ketoloc (Keromin, 30 mg/ ml/ample, Ketorolac tromethamin, Hana Pharm Co., Seoul, Korea) 를통증을호소할때정주하였으며, 1 시간뒤에도지속적 으로통증호소시에 Fentanyl (Fentanyl, 100 mcg/2 ml/ample, Fentanyl citrate, Gu Ju Pharm Co., Seoul, Korea) 를반앰플을 사용하였다. 수술후 2 일째까지 visual analogue scale (VAS) 를 a b c Snarebody Guideneedle Main body Handle Snare Fig. 2. (A) Hold port is composed of snare body (a), guide needle (b) and main body (c), initially combination of the (b) and (c) are used for the insertion into the abdominal cavity. When the hold port is inserted, (b) is removed and then insert (a). (B) The snare's size can be reduced by moving handle of backward. A B 이용하여통증을측정하였고, VAS 는 0부터 10 까지측정되었다. 미용적만족도는 1부터 5로나누어순서대로, 매우만족, 만족, 보통, 불만족, 매우불만족으로나누어수술후 7일재외래에서추적관찰시에측정하였고, 수술후 3개월후에전화연락을취하여다시측정하였다. 자료의통계적분석은 IBM SPSS statistics 18.0 프로그램을이용하였다. 연속변수는 T 검정, Mann-Whitney 검정, 명목변수는 χ 2 검정과 Fisher`s exact 검정을사용하여분석하였고, p값이 0.05 미만인경우를통계적으로유의한것으로판정하였다. 결과 2010 년 3월부터 10 월까지 SLC 또는 CLC를시행받은환자들의나이, 성별, 신체비만지수 (mean body index, BMI), 복부수술과거력의유무및수술후결과에대해조사하였다 (Table 1). 먼저, SLC 를시행받은 14 명의환자군과 CLC를시행받은 39명의환자군의임상적특징을보면, SLC 군에는남성 6명, 여성 8명이포함이되었으며 CLC군에는남자 21 명, 여성 18 명이포함이되었다. 각군의평균연령은 37세와 48세로 SLC 군이연령이낮았고 (p=0.008), BMI 의경우각각 23.4 과 23.7 로나타났으며 (p=0.820) 이전에복부수술력이있는환자는각각 2명과 8 명이포함이되었다 (p=0.100). 수술전진단은 SLC 군의경우복부증상을동반한담석증이 6명, 담낭용종이 3명, 만성담낭염이 5명이었으며, CLC군의경우유증상담석증이 8명, 담낭용종이 8명, 만성담낭염이 23명으로나타났다 (p=0.204). 이외에도 SLC 군과 CLC군의수술과관련된결과들을보면수술중담낭천공의유무의경우양군각각 3명과 8명으로평균 20% 에서발생하였으나, 통계적인유의성은없었다 (p=0.100). 수술시간은 SLC 를시행받은군이 66.8 분, CLC군이 50분으로통계적으로유의하게 SLC 군이더길었지만 (p=0.002), 수술시간은초기 3예를기점으로단축되어서평균 59분의수술시간을형성하는것을보여주었다 (Fig. 3). 수술후재원일수의경우 SLC 군이 4.6 일, CLC를시행받은군이 5.1 일이었고 (p=0.184), 양군모두에서수술후창상감염및개복수술로의전환은없었다 (Table 1). 수술후 2일째까지의 VAS 점수는 SLC 군과 CLC 군에서통계학적인차이는없었지만 (p=0.801, p=0.264, p=0.536), 수술후 3개월째미용적만족도는 SLC 군에서 CLC 군보다각각 1.07, 1.64 로 SLC 군에서의만족도가의미있게높았다 (p=0.036). 고찰 1997 년 Navarra et al. 4 이처음으로단일공복강경하담낭절제술 (SLC) 을시행한이후로최근까지복강경기구의발달과여 Journal of Minimally Invasive Surgery Vol. 18. No. 4, 2015
109 Table 1. Patient s characteristics and operative outcome Parameter SLC* (N=14) CLC (N=39) p value Sex 0.480 Male 6 21 Female 8 18 Age (yr), mean±sd(range) 37.0±12.8 (17~59) 48.8±14.0 (23~74) 0.008 BMI (kg/m 2 ), mean±sd (range) 23.4±3.0 (19.02~30.48) 23.7±4.4 (17.58~35.78) 0.820 Previous abdominal operation 2 8 0.100 Preoperative diagnosis 0.204 Gallbladder stones 6 8 Gallbladder polyps 3 8 Chronic cholecystitis 5 23 Intraoperative bile leak (%) 21.4 20.5 0.100 Operative times (min) 66.8 (30~100) 50.0 (20~80) 0.002 Wound infection 0 0 Pain score (VAS ) Day 0 5.4 (4~7) 5.5 (3~7) 0.801 Day 1 3.6 (2~6) 3.9 (2~6) 0.264 Day 2 2.2 (1~5) 2.4 (1~4) 0.536 Total analgesics requirement NSAID (mg) 87.9 (0~150) 90.0 (0~270) 0.901 Opioid (mg) 0.87 (0~1.9) 0.78 (0~1.8) 0.403 Cosmesis score Day 7 1.62 (1~3) 1.77 (1~4) 0.921 3 months 1.07 (1~2) 1.64 (1~3) 0.036 Postoperative hospital stay 4.6 (4~8) 5.1 (4~9) 0.184 Continuous variable are expressed as mean±standard deviation. *Single port laparoscopic cholecystectomy, Conventional (3 or 4-port) laparoscopic cholecystectomy, Body mass index; Visual analogue scale. Minutes 120 100 80 60 40 20 0 Operative time and learning curve 1 2 3 4 5 6 7 8 9 Cases 10 11 12 13 Fig. 3. Operative time and learning curve. The learning curve for modified single port laparoscopic cholecystectomy should be around 3 cases. 14 러종류의다채널포트 (port) 의개발, 복강경카메라기능의향상등으로 SLC 는더욱활발히시행되고있다. 2007 년 Natural Orifice Transluminal Endoscopic Surgery (NOTES) 담낭절제술이보고된후 4,9 SLC 에대한관심이많아지면서다양한수술법들이개발되어왔고각각의안정성과장점들에대해 CLC와비교연구되어왔다. 6,10 특히최근에는 CLC와비교하여수술시간의연장이있을수있지만안전성의차이가없다고보고되면서미용적인장점과함께적응증이늘어가고있다. 11 하지만제한된공간에서여러기구들간의충돌이불가피하고인체공학적으로도기술적어려움이여전히남아있는상태로아직까지는제한된환자군에서만시행되고있는상황이다. 12 또한, 수술의용이함과안전성을높이기위해서는안전한수술시야 (critical view of safety) 를확보하는것이중요한데, 13 SLC 의경우에는이런수술시야를확보하는것이어려울수있다. 따라서이러한 www.e-jmis.org
110 Jin Seok Ohn et al. 한계를보완하기위하여적은투관침을사용하면서담낭을견인하는다양한방법에대해연구가이루어지는추세이다. 14-18 결국안전한시야를확보하면서기구들간의충돌을줄이기위해서는단일공을통해삽입되는기구의수를줄이는것이도움이될수있는데, 이를위해기존에많이시행되는방법으로봉합사를이용하거나, 2 mm 기구등의보조기구를이용하여담낭기저부를견인하는방법이있다. 19,20 이외에도보조기구를사용하지않으면서단일공으로기구들간의충돌을줄이면서지렛대의원리를이용하여 SLC 를시행하는방법이있다. 21 이방법은피부절개창을공유하면서근막의절개창을완전히열기보다는투관침을환자의근막에각각넣는단일절개, 다투관침법으로복강경작업기구들간의충돌을피하기위해 10 mm 카메라투관침에서최대한멀리 5 mm 투관침을위치시키고조명또한꺾인케이블커넥터를사용하여방해를최소화하였다. 하지만이역시집도하는외과의의주시술이왼손으로이루어지는어려움과학습곡선 (learning curve) 이 30예가량으로비교적긴단점이있었다. 또한담낭기저부를견인할때사용되는복벽경유봉합사는담즙유출과견인력감소등이발생할수있고, 16 단일공을통해 endoloop 나 2 mm grasper 를사용하여견인하는경우는담낭기저부견인까지의시간이오래걸리거나다른기구와의충돌이발생할가능성이있다. 17,21 따라서이런문제점등을해결하여투관침개수를줄이면서도담도손상등의합병증의발생을줄이기위한 critical view of safety 를확보하기위하여, 13 본원의술자는 needle grasper 와 endoloop 기능을함께할수있게제작된직경 2 mm의보조기구 Hold port (NELIS, Korea) 를사용하였다. 지금까지보고되 Fig. 4. Hold port site shows minimal scar. Hold port site Single port site 는 SLC 의학습곡선은 8 증례에서 30 증례까지다양하지만, 22 본원에서는초기 3예의적은학습곡선으로 (Fig. 3) 숙련된외과의이외에도쉽게학습할수있는방법이면서수술의안전성과미용적인효과를유지할수있었다. 결과적으로수술시간은 66.8 분으로 CLC군보다는길었는데, 이는초기 3예에서수술시간이연장되었기때문일것으로생각되며, 초기 3예를제외하면평균 59분으로 CLC군과비슷한결과를보였고기존의보고들과비슷하였다. 11 결국충분히담낭기저부를견인함으로써수술시야를확보하여보다안전한수술을할수있으면서, 수술후 2 mm port 반흔 (scar) 은수술후 1주일뒤추적관찰시에거의보이지않았다 (Fig. 4). 담낭기저부의견인방법에대한여러보고들중가장흔한방법으로는봉합사를이용하는것과보조기구를이용하는방법이있다. 봉합사를이용한견인은 2-0 나일론실을이용하여중간쇄골선상의 8-9-10 늑간을통해담낭의장막을통과하게한후다시늑간을통해나오게하여담낭기저부를견인하는방법으로, 담낭의천공으로인한담즙유출가능성이있고견인하는힘이약해서완전한수술시야를확보하는데어려움이있다. 17 최근에새롭게보고된 LEAN Back technique 은복강내에서담낭기저부와횡경막을봉합하여견인하는방법으로역시견인력이충분하지않고담즙유출가능성이있으면서단일공을통해서 needle holder로횡경막을봉합해야하는기술적인문제가있을수있겠다. 14 보조기구를이용한방법으로는 2-mm needlescopic grasper (Minilap grasper; Stryker, San Jose, CA), endoloop (Surgitie; Autosuture, Tyco Healthcare United States Surgical, Norwalk), magnetic forceps (IMANLAP project) 등이보고되고있는데, 환자의우측상복부의정중쇄골선상에작은절개창을이용하는경우와단일공통로를직접이용하는경우가있다. 전자의경우완전한단일공은아니지만추적관찰했을경우미용적인이득에대한보고들이있었고 14-18 후자의경우완전한단일공통로를이용하지만기구들간의충돌은여전히남아있는한계점이었다. 배꼽을통한탈장보고가있었고, 수술후만성통증에대한보고가부족한상황에서기존의 CLC와비교하여 SLC 가우위에있는수술법이될수없다는보고들이있었지만, 12,23 최근대규모연구에서는이러한합병증의발생률이비슷하게보고되고있다. 24 수술직후의통증을수술후사용한진통제와 VAS 점수를사용하여비교하였을때, 본연구에서는두군간의의미있는차이는없었지만, 최근연구들에서는두군간에차이가없다는보고부터 10 수술시간의연장과, 단일공절개창의크기가기존의배꼽의절개창보다커서오히려수술직후통증이높다는보고까지다양하게발표되고있다. 25 하지만단일공단독에의한수술보다수술시간을단축하고배꼽을통한투관침 Journal of Minimally Invasive Surgery Vol. 18. No. 4, 2015
111 숫자를줄여주는것들이미용적인이득뿐만아니라수술후통증을줄일수있는한방법이될수있고이런점들이보조기구등을이용한변형단일공담낭절제술 (modified single port laparoscopic cholecystectomy) 의장점이될수있겠다. 비록본연구는오직한명의집도의에의해서초기 14 예의적은환자군을대상으로시행되었고수술직후통증을의미있게감소시켜주지는못하였지만, 미용에대한환자만족도를높이면서 5년간장기적인추적관찰을하였을때, 절개창의탈장, 만성통증등의발생이없었고 SLC 의경험이적은집도의가초기 3예의아주적은학습곡선으로안전하게수술을적용할수있었던것에의의가있을수있겠다. 비록본연구에서는수술의적응증이염증이심하지않은, 양성담낭질환만으로제한이되었지만, 집도의의경험이지속적으로축적이된다면점차염증이심한경우나해부학적변형이있는경우로확대하여적용시킬수있을것으로생각된다. 결론적으로단일공담낭절제술에있어서본원에서사용한보조기구의사용은단일공단독수술보다는안전한수술시야를확보함으로써적은학습곡선으로도안전하게수술할수대안이라고생각되며, 미용적으로도 2 mm 보조기구를사용한부위는상처가남지않아단일공단독수술을보완할수있는우수한수술방법이라고사료된다. REFERENCES 1) Soper NJ, Stockmann PT, Dunnegan DL, Ashley SW. Laparoscopic cholecystectomy. The new 'gold standard'? Arch Surg 1992; 127:917-921; discussion 921-913. 2) Mori T, Ikeda Y, Okamoto K, et al. A new technique for twotrocar laparoscopic cholecystectomy. Surg Endosc 2002;16:589-591. 3) Slim K, Pezet D, Stencl J Jr, et al. Laparoscopic cholecystectomy: an original three-trocar technique. World J Surg 1995;19:394-397. 4) Navarra G, Pozza E, Occhionorelli S, Carcoforo P, Donini I. Onewound laparoscopic cholecystectomy. Br J Surg 1997;84:695. 5) Sharma A, Soni V, Baijal M, Khullar R, Najma K, Chowbey PK. Single port versus multiple port laparoscopic cholecystectomy-a comparative study. Indian J Surg 2013;75:115-122. 6) Saad S, Strassel V, Sauerland S. Randomized clinical trial of single-port, minilaparoscopic and conventional laparoscopic cholecystectomy. Br J Surg 2013;100:339-349. 7) Reibetanz J, Ickrath P, Hain J, Germer CT, Krajinovic K. Singleport laparoscopic cholecystectomy versus standard multiport laparoscopic cholecystectomy: a case-control study comparing the long-term quality of life and body image. Surg Today 2013;43: 1025-1030. 8) Ma J, Cassera MA, Spaun GO, Hammill CW, Hansen PD, Aliabadi-Wahle S. Randomized controlled trial comparing singleport laparoscopic cholecystectomy and four-port laparoscopic cholecystectomy. Ann Surg 2011;254:22-27. 9) Marescaux J, Dallemagne B, Perretta S, Wattiez A, Mutter D, Coumaros D. Surgery without scars: report of transluminal cholecystectomy in a human being. Arch Surg 2007;142:823-826; discussion 826-827. 10) Qiu J, Yuan H, Chen S, He Z, Han P, Wu H. Single-port versus conventional multiport laparoscopic cholecystectomy: a metaanalysis of randomized controlled trials and nonrandomized studies. J Laparoendosc Adv Surg Tech A 2013;23:815-831. 11) Zehetner J, Pelipad D, Darehzereshki A, Mason RJ, Lipham JC, Katkhouda N. Single-access laparoscopic cholecystectomy versus classic laparoscopic cholecystectomy: a systematic review and meta-analysis of randomized controlled trials. Surg Laparosc Endosc Percutan Tech 2013;23:235-243. 12) Alptekin H, Yilmaz H, Acar F, Kafali ME, Sahin M. Incisional hernia rate may increase after single-port cholecystectomy. J Laparoendosc Adv Surg Tech A 2012;22:731-737. 13) Berci G, Morgenstern L. An analysis of the problem of biliary injury during laparoscopic cholecystectomy. J Am Coll Surg 1995; 180:638-639. 14) You KC, Yoo T, Park SG, et al. How to do single-port laparoscopic cholecystectomy using LEAN BACK technique. ANZ J Surg 2015;85:284-285. 15) Sulu B, Diken T, Altun H, et al. A comparison of single-port laparoscopic cholecystectomy and an alternative technique without a suspension suture. Ulus Cerrahi Derg 2014;30:192-196. 16) Kim MJ, Kim TS, Kim KH, An CH, Kim JS. Safety and feasibility of needlescopic grasper-assisted single-incision laparoscopic cholecystectomy in patients with acute cholecystitis: comparison with three-port laparoscopic cholecystectomy. J Laparoendosc Adv Surg Tech A 2014;24:523-527. 17) Uras C, Boler DE. Endoloop retraction technique in singleport laparoscopic cholecystectomy: experience in 27 patients. J Laparoendosc Adv Surg Tech A 2013;23:545-548. 18) Dominguez G, Durand L, De Rosa J, Danguise E, Arozamena C, Ferraina PA. Retraction and triangulation with neodymium magnetic forceps for single-port laparoscopic cholecystectomy. www.e-jmis.org
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