Laparoscopic aortic surgery learning curve: experimental study in pigs

Abstracts

BACKGROUND: Laparoscopic aortic surgery (LAS) is evolving as a minimal invasive alternative technique for the treatment of abdominal aortic aneurysms and peripheral aortoiliac arterial disease. Few articles have objectively evaluated the technique learning curve in vascular surgery. OBJECTIVE: The aim of the present experimental study was to demonstrate surgical feasibility and evaluate each surgical step of LAS. METHODS: Between October 2007 and January 2008, two beginning surgeons attended laparoscopic courses and operated on six consecutive pigs with a total laparoscopic retroperitoneal aortic dissection and interposition of a Dacron tube graft in the infrarenal aortic segment. Both anastomoses were performed under total laparoscopic technique. RESULTS: All surgical time curves decreased along time: 45.9% in total surgical time, 85.8% in dissection time, 81.2% in aortic exposure, 55.1% in total cross-clamping, 71% in proximal anastomosis and 64.9% in distal anastomosis. CONCLUSION:This experimental study showed that satisfactory results with LAS were only reached after a long learning curve. However, this learning curve decreased along time, as experience with the technique, materials and non-stereoscopic vision improved. Vascular surgeons should attend practical courses and should have training opportunities in simulators and animals to achieve results similar to those of conventional surgery.

Video-assisted surgery; aorta; vascular diseases; learning; animal models

CONTEXTO: A cirurgia videolaparoscópica (CVL) vem evoluindo como alternativa cirúrgica menos invasiva para o tratamento da doença aterosclerótica oclusiva aorto-ilíaca e do aneurisma da aorta abdominal. Poucos estudos avaliaram objetivamente a curva de aprendizado com essa técnica em cirurgia vascular. OBJETIVO: Avaliar objetivamente os tempos e a evolução de cada passo cirúrgico e demonstrar a exeqüibilidade dessa técnica. MÉTODOS: Entre outubro 2007 e janeiro de 2008, dois cirurgiões vasculares iniciantes na CVL operaram, após cursos e treinamentos, seis porcos consecutivos, com dissecção aórtica e interposição de um enxerto de dácron em um segmento da aorta infra-renal abdominal, com técnica totalmente laparoscópica. RESULTADOS: Todos os tempos cirúrgicos foram decrescentes ao longo do estudo, apresentando redução de 45,9% no tempo total de cirurgia, 85,8% no tempo de dissecção da aorta, 81,2% na exposição da aorta, 55,1% no clampeamento total, 71% na confecção da anastomose proximal e 64,9% na anastomose distal. CONCLUSÃO: O presente estudo mostrou que os resultados técnicos satisfatórios da CVL vascular ocorreram somente após longa curva de aprendizado, que foi decrescente ao longo do tempo, à medida que aumentou a experiência e vivência com os materiais e com a visão não-estereoscópica. Essa técnica pode ser realizada com perfeição por cirurgiões vasculares desde que façam cursos especializados, com treinamento em simuladores e animais, e desde que busquem constante aprimoramento a fim de conseguir resultados similares aos obtidos com a cirurgia convencional.

Cirurgia videoassistida; aorta; doenças vasculares; aprendizagem; modelos animais

ORIGINAL ARTICLE

Laparoscopic aortic surgery learning curve: experimental study in pigs

Ricardo de Alvarenga Yoshida^I; Winston Bonetti Yoshida^II; Hamilton de Almeida Rollo^II; Ralf Kolvenbach^III; Sílvia Elaine Rodolfo de Sá Lorena^IV

^IGraduate student. Vascular and endovascular surgeon. Collaborator, Angiology, Vascular and Endovascular Surgery Department, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil

^IIProfessor. Associate professor, Angiology, Vascular and Endovascular Surgery Department, Faculdade de Medicina de Botucatu, UNESP, Botucatu, SP, Brazil

^IIIProfessor. Head, Vascular and Endovascular Surgery Service, Hospital Augusta, Dusseldorf, Germany

^IVPhD student, Department of Veterinary Anesthesiology and Surgery, Faculdade de Medicina Veterinária e Zootecnia (FMVZ), UNESP, Botucatu, SP, Brazil

Correspondence

ABSTRACT

BACKGROUND: Laparoscopic aortic surgery (LAS) is evolving as a minimal invasive alternative technique for the treatment of abdominal aortic aneurysms and peripheral aortoiliac arterial disease. Few articles have objectively evaluated the technique learning curve in laparoscopic vascular surgery.

OBJECTIVE: The aim of the present experimental study was to demonstrate surgical feasibility and evaluate each surgical step of LAS.

METHODS: Between October 2007 and January 2008, two beginning surgeons attended laparoscopic courses and operated on six consecutive pigs with a total laparoscopic retroperitoneal aortic dissection and interposition of a Dacron tube graft in the infrarenal aortic segment. Both anastomoses were performed under total laparoscopic technique.

RESULTS: All surgical time curves decreased along time: 45.9% in total surgical time, 85.8% in dissection time, 81.2% in aortic exposure, 55.1% in cross-clamping, 71% in proximal anastomosis and 64.9% in distal anastomosis.

CONCLUSION: This experimental study showed that satisfactory results with LAS were only reached after a long learning curve. However, this learning curve decreased along time, as experience with the technique, materials and non-stereoscopic vision improved. Vascular surgeons should attend practical courses and should have training opportunities in simulators and animals to achieve results similar to those of conventional surgery.

Keywords: Video-assisted surgery, aorta, vascular diseases, learning, animal models.

VIDEO

^{Laparoscopic aortic surgery learning curve: experimental study in pigs} (a08f01.mpg)

Laparoscopic aortic surgery learning curve: experimental study in pigs

Ricardo de Alvarenga Yoshida; Winston Bonetti Yoshida; Hamilton de Almeida Rollo; Ralf Kolvenbach; Sílvia Elaine Rodolfo de Sá Lorena

J Vasc Bras. 2008;7(3):231-238.

Introduction

Laparoscopic aortic surgery (LAS) has been evolving as a less invasive surgical alternative for the treatment of varied diseases.^1-6 Initially, the same interest and enthusiasm for LAS has not been observed in vascular surgery.^1,7 Initial technical difficulties in vascular dissection and clamping, lack of specific materials and accessories, long learning curve did not encourage many vascular surgeons to dedicate to this laparoscopic technique.^1,7,8

However, some centers, especially in Europe and Canada, reached remarkable advancement in LAS, making such vascular surgical technique accessible and standardized.^1,3,9-12

The advantages of videolaparoscopic vascular surgery for aortic reconstructions are the same expected in other gastrointestinal or urological laparoscopic surgeries, i.e., are less invasive, have reduced surgical trauma, shorter abdominal incision and postoperative pain, early oral feeding, and shorter hospital stay.^5,8,13-17 Laparoscopic aortic surgeries had similar or better results than those obtained with conventional open surgery when compared with hemodynamic, metabolic and inflammatory parameters^17-21 and long-term follow-up.^5,8,13-17

One of the limitations of LAS is the long learning curve required to obtain technical success.^1,3 Few studies have been conducted to prospectively and specifically evaluate this detail of the technique.^23-28

Therefore, this experimental study aims to objectively evaluate the times and evolution of each surgical step and demonstrate feasibility of this technique.

Methods

This study was performed from March 2007 through January 2008 as part of a graduation project. It was approved by the Animal Research Ethics Committee. A prospective analysis of the surgical times required to complete each stage of the operative technique in pigs was performed. Only a descriptive statistical analysis of the data was performed.

Throughout this pilot study in pigs, the authors attended courses of general laparoscopic surgery (8 and 30 hours) and gynecological laparoscopic surgery (32 hours). They also had an intensive training of suture and knots using a black box (about 60 hours).

Next, six Landrace pigs of both genders, weighing between 20-30 kg, in good health conditions, were submitted to a totally laparoscopic surgery. All the surgeries were performed at the Laboratory of Experimental Surgery of the Department of Surgery and Orthopedics at Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP) (Figure 1A).

The animals were submitted to a 14-hour fasting, and water ad libitum. Intramuscular preanesthetic medication was administered combining acepromazine (0.1 mg/kg), xylazine (1 mg/kg), ketamine chloride (8 mg/kg), and morphine (0.5 mg/kg) Fifteen minutes after application, the central vein of the ear was punctured using a 22 G needle (Abbocath^®), and anesthesia was induced by intravenous administration of ketamine chloride (2 mg/kg) and propofol (4 mg/kg). Maintenance was performed using halothane. Next, the animal was placed in prone position on the procedure table for orotracheal intubation with a 7.0 probe. Volume-controlled ventilation was applied using a respirator model 674 of the K. Takaoka anesthesia device (mod. 2.600, Nikkei, Brazil). The current volume was standardized in 20 mL/kg^-1 of O_2, and respiratory frequency in 10-12 mov min^-1 to maintain final expiratory pressure of CO₂ (PETCO₂) between 30-35 mmHg. Saturation of O₂ was measured by pulse oximetry, placing a sensor on the animal's tongue, at a value above 97%. Fluid therapy was performed using a 10 mL/kg infusion of Ringer's lactate.

Surgical technique

All the surgeries were performed by a main surgeon and by an auxiliary, who accumulated the functions of camera and surgical assistant. The equipment used were the sets for laparoscopic surgery by Storz, Astus or Olympus, according to availability.

After placing the animal in right side prone position (Figure 1B), the pneumoperitoneum was started after puncture using a Veress needle in the left subcostal space and maintained with a 12 mm Hg pressure of CO₂. Next, an 11-mm trocar was placed above the umbilicus to introduce a 30º optics. Two other 11-mm trocars (Endopath, Johnson & Johnson) were placed in the medial line, below and above the umbilicus. In addition, four other trocars were placed around the left side, having the costal ridge, medial axillary line, dorsal muscles and iliac crest as reference (Figure 1B).

Exposure of the aorta started with the medial mobilization of the left hemicolon, left kidney and splenic flexure, using grasper, laparoscopic scissors and harmonic scalpel (ULTRACISION,^® Johnson & Johnson). Gerota fascia was exposed, and the left hemicolon was detached, according to the Apron technique²⁹ (Figures 2A and B). After complete dissection of the aorta and its bifurcation (Figures 2C and 2D), the aortic lumbar arteries were ligated using Liga-clip^® (Johnson & Johnson) or electrocoagulated using a harmonic scalpel (ULTRACISION^®, Johnson & Johnson). A laparoscopic aortic clamp (Storz Laparoscopic Vascular Clamp, ref. 49310VC) was placed in the infrarenal aorta, and another clamp in the aorta just above its bifurcation, through portals located below the costal ridge and iliac crest, respectively. After administration of endovenous heparin (100 IU/kg), the aorta was clamped and sectioned (Figure 2E). A longitudinal aortotomy measuring about 6 cm was performed between both clamps (Figure 2F). A vascular 6-mm Dacron graft was introduced through one of the portals, and proximal anastomosis was performed laparoscopically using a continuous Prolene^® 4-0 suture (Johnson & Johnson) through a laparoscopic needle holder (Storz, ref. 49310NL), according to the technique described by Coggia et al.³⁰ After proximal anastomosis, blood flow was temporarily released to observe remaining bleedings, which were repaired with additional stitches whenever present (Figure 3A). After re-clamping, distal anastomosis was performed in the same manner (Figure 3B).

After the anastomoses were performed, flow in the distal anastomoses was released, letting the air out of the graft, and then in the proximal anastomosis, thus restoring perfusion into the lower limbs (Figure 3C). The bleedings that remained after proximal and distal anastomoses were repaired using additional stitches. The graft was covered by the left hemicolon and by the peritoneum, placing the animal back to the horizontal supine position.

By the end of the procedure, the animals were euthanatized using endovenous potassium chloride under general anesthesia.

Results

Means of total surgical time, cross-clamping time and distal anastomosis time could only be calculated after the third surgery, as it was not possible to complete all surgical steps initially. Initial technical problems to perform the totally laparoscopic surgery, especially to perform anastomosis, required very long surgical time.

Mean total surgical time was 185 minutes (130-240 min), with decreasing partial times of 240, 180, 180 and 130 minutes for the surgeries performed in pigs 3, 4, 5 and 6, respectively (45% reduction between the third and the last surgery) (Figure 4). Mean dissection and aortic exposure times before clamping were 20 minutes (5-35 min), with decreasing times of 35, 21, 14, 16, 10 and 5 minutes (85% reduction between the first and the last surgery), and 28.5 minutes (9-48 min), with decreasing times of 48, 14, 13, 19, 9 and 9 minutes (81.2% reduction between the first and the last surgery), respectively (Figure 5). Mean surgical time for retroperitoneal exposure of the aorta, before clamping, using the Apron technique, as well as its dissection and external ligation of lumbar arteries with clips (Liga-clip^®, Johnson & Johnson) or electrocoagulation using a harmonic scalpel (ULTRACISION^®, Johnson & Johnson) was 48.5 minutes (decreasing from 83 to 14 min). Mean cross-clamping time was 115.5 minutes, with decreasing times of 157, 166, 82 and 74 minutes (52.8% reduction between the third and the last surgery), for the surgeries performed in pigs 3, 4, 5 and 6, respectively (Figure 6).

Mean proximal anastomosis time was 64.5 minutes, with decreasing times of 100, 50, 40, 38, 46 and 29 minutes (71% reduction between the first and the last surgery) (Figure 7). Application of additional hemostatic stitches was required in two pigs. Mean distal anastomosis time was 47 minutes, with decreasing times of 57, 38, 48 and 37 minutes (35% reduction between the third and the last surgery), for the surgeries performed in pigs 3, 4, 5 and 6, respectively (Figure 7).

There were no inadvertent lesions in blood vessels or neighboring structures. In the second surgery, one animal died before being sacrificed due to problems in the anesthesia device, related to poor diffusion of anesthetic gases.

Autopsy was performed in the sixth surgery to verify both anastomoses, and there were no technical defects, stenoses or leakages.

In the final inventory of the abdominal cavity, there were no lesions of intracavity organs in any of the six surgeries.

Discussion

The laparoscopic aortic surgery was firstly described by Dion in 1993.³¹ It has evolved until being routinely performed in most patients with aortoiliac occlusive disease or abdominal aortic aneurysm (AAA),^{3,10,11,32-35} in addition to being an adjunct in endovascular procedures, characterizing hybrid techniques.^15,33,36-38 Nowadays, three main technique are employed for aortic reconstructions: hand-assisted laparoscopic surgery (HALS), minimally invasive laparoscopic surgery (minilaparotomy) and totally laparoscopic surgery.¹

At Augusta Hospital (Prof. Kolvenbach service, in Dusseldorf, Germany) from 2002 to 2006, 131 patients diagnosed with AAA were operated using the totally laparoscopic technique. After a mean follow-up time of 39 months, 127 patients were alive and being regularly followed.³_.

However, to achieve such results, a long learning curve had to be overcome. In the present study, it was not possible to end the first surgeries and the time to perform proximal anastomosis was initially longer than the total time of the last completed surgeries. However, throughout time, all temporal curves of total surgical time, aortic dissection and exposure, proximal and distal anastomoses and cross-clamping had a decreasing profile, not only due to the experience acquired with the surgeries, but also from training using the black box and theoretical and practical courses in laparoscopic surgery attended during this study period. Such courses provided the authors with resources, techniques of knots and sutures, in addition to protocols and training in simulators, which, although focused on general, gynecological and urological surgery, contributed to reduced surgical time. Another important factor to reduce surgical time was the use of a harmonic scalpel, which facilitated aortic dissection and exposure due to its effective cutting and coagulation power, without dissipating heat or causing smoke, minimizing undesirable bleedings. It can be used in periaortic tissues, which are often bleeding sites. However, reduced surgical times could be even more significant if the surgeries had been performed by a main surgeon and two assistants, as suggested in the literature, since the accumulation of camera and surgical assistant by a single assistant surgeon makes performance of anastomoses even more difficult.

At the Department of Vascular Surgery of University of Pisa, Italy, headed by Prof. Mauro Ferrari, there was significant reduction in surgical steps and clamping times, after learning curve, in at least 30 patients, corroborating the data of this study on decreasing surgical times during the learning curve as the experience of successive cases sums up.^1,11

Dion et al.,²³ in an experimental study involving six pigs, showed the feasibility of end-to-side suture performed laparoscopically, with mean total surgical time of 198 minutes (170-240 min). Fusco et al.³⁶ obtained cross-clamping time for aortofemoral surgery of 1 hour in an operated pig. Compared with the present study, mean times were similar for anastomoses (64.5 min for proximal anastomosis and 47 min for distal anastomosis) and for mean total surgical time (185 min). Difference in mean times for aortic dissection and exposure (48.5 min) before clamping and in cross-clamping (115.5 min) was due to the different surgical procedures performed in these studies.³⁶ Laparoscopic aortic surgery can only be performed when the surgeon and a well trained team, comprised of at least one assistant responsible for the camera and another assistant for the surgery itself, have acquired basic laparoscopic skills^1,3,10,17,33 and are in perfect harmony. It does not matter if such skills arise from laparoscopic surgical procedures of general surgery or from laparoscopic courses focused on other specialties.^1,3 Currently in Brazil there are no courses focusing on vascular surgery or even vascular surgery services routinely using the vascular laparoscopic technique. In addition, there are no vascular laparoscopic surgeries considered "minor" to start and practice this technique, such as the case of other specialties.^1,3 Those interested should search knowledge in general laparoscopic courses and training in simulators and experimental animals before taking risks in the treatment of vascular patients using LAS. Good quality and specific materials for vascular laparoscopy must be used.

A limitation for the development of this technique is its long learning curve, and it is currently difficult to form a well trained team, due to all aspects previously mentioned.¹ Furthermore, the equipment, materials and clamping are not cheap. However, LAS, which is nothing more than the conventional surgery performed laparoscopically, has presented good results associated with technical elegance, low invasiveness and safety; such results should be the motivation to make vascular surgeons start this learning.^1,3

The present study showed that the satisfactory technical results of LAS only occur after a long learning curve, which decreases as the experience and familiarity with the materials and the non-stereoscopic view increase. This technique can be successfully performed by vascular surgeons, just like general, gynecological and urological surgeons perform complex laparoscopic surgeries. Intensive training, laparoscopy courses and constant search of technical enhancement should be pursued to obtain the same results of conventional surgery.

Acknowledgements

The authors thank the enterprises Johnson & Johnson - Ethicon Endo-Surgery Division, Karl Storz Germany and Brazil, H. Strattner and Astus, for supporting and providing equipment and materials for this project. They also thank H. Strattner for sponsoring the videolaparoscopic course.

References

• 1. Kolvenbach R, Yoshida RAY. Cirurgia aórtica videolaparoscópica. In: Maffei FHA, ed. Doenças vasculares periféricas. 4Ş ed. Rio de Janeiro: Guanabara Koogan; 2008. v. 2. "No prelo".
• 2. Lin JC, Kolvenbach R, Schwierz E, Wassiljew S. Total laparoscopic aortofemoral bypass as a routine procedure for the treatment of aortoiliac occlusive disease. Vascular. 2005;13:80-3.
• 3. Kolvenbach R. Total laparoscopic aortic aneurysm surgery. Acta Chir Belg. 2006;106:36-9.
• 4. Coggia M, Javerliat I, Di Centa I, et al. Total laparoscopic infrarenal aortic aneurysm repair: preliminary results. J Vasc Surg. 2004;40:448-54.
• 5. Coggia M, Di Centa I, Javerliat I, Alfonsi P, Kitzis M, Goeau-Brissonniere OA. Total laparoscopic abdominal aortic aneurysms repair. J Cardiovasc Surg (Torino). 2005;46:407-14.
• 6. Kolvenbach R, Ceshire N, Pinter L, Da Silva L, Deling O, Kasper AS. Laparoscopy-assisted aneurysm resection as a minimal invasive alternative in patients unsuitable for endovascular surgery. J Vasc Surg. 2001;34:216-21.
• 7. Ahn SS, Ro KM. Laparoscopic aortobifemoral bypass. Ann Vasc Surg. 1998;12:625-8.
• 8. Kolvenbach R, Da Silva L, Deling O, Schwierz E. Video-assisted aortic surgery. J Am Coll Surg. 2000;190:451-7.
• 9. Javerliat I, Coggia M, Di Centa I, Kitzis M, Mercier O, Goeau-Brissonniere O. Total laparoscopic abdominal aortic aneurysm repair with reimplantation of the inferior mesenteric artery. J Vasc Surg. 2004;39:1115-7.
• 10. Dion YM, Cardon A, Hartung O, Gracia CR. Laparoscopic Aorto-Iliac Surgery: Present Status and Future Perspectives. Surg Technol Int. 2000;VIII:201-207.
• 11. Ferrari M, Adami D, Del Corso A, et al. Laparoscopy-assisted abdominal aortic aneurysm repair: early and middle-term results of a consecutive series of 122 cases. J Vasc Surg. 2006;43:695-700.
• 12. Mercier O, Coggia M, Javerliat I, Di Centa I, Colacchio G, Goeau-Brissonniere O. Total laparoscopic repeat aortic surgery. J Vasc Surg. 2004;40:822-5.
• 13. Kolvenbach R. The role of video-assisted vascular surgery. Eur J Vasc Endovasc Surg. 1998;15:377-9.
• 14. Silva L, Kolvenbach R, Pinter L. The feasibility of hand-assisted laparoscopic aortic bypass using a low transverse incision. Surg Endosc. 2002;16:173-6.
• 15. Wassiljew S, Kolvenbach R, Puerschel A, Schwierz E. Total laparoscopic iliac artery aneurysm repair using endoscopic techniques and endovascular balloon occlusion. Eur J Vasc Endovasc Surg. 2006;32:270-2.
• 16. Dion YM. History and perspectives in laparoscopic vascular surgery. Acta Chir Belg. 2004;104:493-8.
• 17. Munro MG. Laparoscopic access: complications, technologies, and techniques. Curr Opin Obstet Gynecol. 2002;14:365-74.
• 18. Kolvenbach R, Deling O, Schwierz E, Landers B. Reducing the operative trauma in aortoiliac reconstructions--a prospective study to evaluate the role of video-assisted vascular surgery. Eur J Vasc Endovasc Surg. 1998;15:483-8.
• 19. Alfonsi P, Vieillard-Baron A, Coggia M, et al. Cardiac function during intraperitoneal CO₂ insufflation for aortic surgery: a transesophageal echocardiographic study. Anesth Analg. 2006;102:1304-10.
• 20. Byrne J, Hallett JW Jr., Ilstrup DM. Physiologic responses to laparoscopic aortofemoral bypass grafting in an animal model. Ann Surg. 2000;231:512-8.
• 21. Polat C, Yilmaz S, Serteser M, Koken T, Kahraman A, Dilek ON. The effect of different intraabdominal pressures on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy. Surg Endosc. 2003;17:1719-22.
• 22. Coggia M, Javerliat I, Di Centa I, et al. Total laparoscopic versus conventional abdominal aortic aneurysm repair: a case-control study. J Vasc Surg. 2005;42:906-10; discussion 911.
• 23. Dion YM, Hartung O, Gracia C, Doillon C. Experimental laparoscopic aortobifemoral bypass with end-to-side aortic anastomosis. Surg Laparosc Endosc. 1999;9:35-8.
• 24. Fusco PEB, Marino HLT, Natal SRB, et al. Enxerto aorto-femoral por via laparoscópica modelo experimental. J Vasc Bras. 2005;4:396-400.
• 25. Dion YM, Gracia C. Experimental laparoscopic aortic aneurysm resection and aortobifemoral bypass. Surg Laparosc Endosc. 1996;6:184-90.
• 26. Dion YM, Gaillard F, Demalsy JC, Gracia CR. Experimental laparoscopic aortobifemoral bypass for occlusive aortoiliac disease. Can J Surg. 1996;39:451-5.
• 27. Dion YM, Chin AK, Thompson TA. Experimental laparoscopic aortobifemoral bypass. Surg Endosc. 1995;9:894-7.
• 28. Dion YM, Cardon A, Gracia CR, Doillon C. A model for laparoscopic aortic aneurysm resection. Surg Endosc. 1999;13:654-7.
• 29. Dion YM, Thaveau F, Fearn SJ. Current modifications to totally laparoscopic "apron technique". J Vasc Surg. 2003;38:403-6.
• 30. Coggia M, Bourriez A, Javerliat I, Goeau-Brissonniere O. Totally laparoscopic aortobifemoral bypass: a new and simplified approach. Eur J Vasc Endovasc Surg. 2002;24:274-5.
• 31. Dion YM, Katkhouda N, Rouleau C, Aucoin A. Laparoscopy-assisted aortobifemoral bypass. Surg Laparosc Endosc. 1993;3:425-9.
• 32. Dion YM, Griselli F, Douville Y, Langis P. Early and mid-term results of totally laparoscopic surgery for aortoiliac disease: lessons learned. Surg Laparosc Endosc Percutan Tech. 2004;14:328-34.
• 33. Kolvenbach R, Schwierz E, Wasilljew S, Miloud A, Puerschel A, Pinter L. Total laparoscopically and robotically assisted aortic aneurysm surgery: a critical evaluation. J Vasc Surg. 2004; 39:771-6.
• 34. Memon MA, Fitzgibbons RJ, Jr. Hand-assisted laparoscopic surgery (HALS): a useful technique for complex laparoscopic abdominal procedures. J Laparoendosc Adv Surg Tech A. 1998;8:143-50.
• 35. Zucker KA. Perceived future of laparoscopic general surgery. Can J Surg. 1992;35:297-304.
• 36. Kolvenbach R, Schwierz E. Combined endovascular/laparoscopic approach to aortic pseudoaneurysm repair. J Endovasc Surg. 1998;5:191-3.
• 37. White GH, Yu W, May J, Chaufour X, Stephen MS. Endoleak as a complication of endoluminal grafting of abdominal aortic aneurysms: classification, incidence, diagnosis, and management. J Endovasc Surg. 1997;4:152-68.
• 38. Kolvenbach R, Lin J. Combining laparoscopic and endovascular techniques to improve the outcome of aortic endografts. Hybrid techniques. J Cardiovasc Surg (Torino). 2005;46:415-23.

Publication Dates

• Publication in this collection
  14 Apr 2009
• Date of issue
  Sept 2008