Video-assisted, retroperitoneal approach for abdominal aortic aneurysm exclusion

Video-assisted, Abdominal

Retroperitoneal Aortic Aneurysm

Martin T. Grune, MD, Kenric M. Murayama,

Abdominal aortic aneurysm (MA) repair is a common procedure associated with significant morbidity and mortality. Although attempts have been made to reduce operative risk in patients with significant comorbid disease by combining aneurysm exclusion with axillofemoral bypass, the morbidity is not greatly reduced when the standard operative approach is required for exclusion. The authors describe a technique for staple exclusion of AAA using a minimally invasive, video-assisted retroperitoneal approach. Am J Sorg. 1996;172:363-366. tandard therapy of infrarenal abdominal aortic aneurysm (AAA), which involves placing a synthetic graft within the aneurysmal segment, is associated with a mortality rate that may be as high as 5%.’ This mortality rate may double if the patients have significant cardiac, pulmonary, or renal dysfunction.2 The high risk of standard repair excludes some individuals, leaving them at risk of rupture and exsanguination. Furthermore, many frail elderly individuals surviving standard operative repair do not return to their normal level of activity.3 Exclusion of the AAA with re-establishment of lower extremity blood flow via axillobifemoral bypass was developed in an attempt to reduce the morbidity and mortality associated with open aneurysmorrhaphy.4-6 Because the risk of rupture was not reduced by attempts at outflow occlusion and aneurysm thrombosis alone, both outflow and proximal inflow exclusion are required to minimize the risk of rupture. When an open surgical technique is used for proximal aortic aneurysm exclusion, the morbidity in comparison with standard repair is not significantly reduced. Furthermore, the patency of the axillofemoral bypass was clearly inferior to anatomic reconstruction. Minimally invasive surgical techniques have been shown to decrease operative morbidity and reduce postoperative recovery. ’ These techniques have been used in the treatment of aortoiliac occlusive disease.8,9 Recent reports of axillofemoral bypass graft using externally supported ring grafts have shown a marked improvement in patency to levels comparable with standard anatomic repair.5 We have developed a minimally invasive retroperitoneal approach to

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From the Department of Surgery and Division of Urology, University of Nebraska Medical Center, Omaha, Nebraska. Requests for reprints should be addressed to Timothy Baxter, MD, University of Nebraska Medical Center, 600 South 42nd Street, Omaha, Nebraska 68198-3280. Manuscript submitted November 21, 1995 and accepted in revised form April 1, 1996.

Medica,

Inc.

Approach Exclusion

for

MD, Thomas G. Lynch, MD, 6. Timothy Baxter, MD

Omaha,

0 1996 by Excerpta All rights reserved.

-. -7

Nebraska

aneurysm bypass.

exclusion

combined

with

standard

axillofemoral

TECHNIQUE The aorta is approached through the left retroperitoneum. To facilitate both AAA exclusion and axillobifemoral bypass, the patient is affixed to the operating room table in a modified left flank position at approximately a 45” angle to the table. The table is flexed to maximize the distance between the costal margin and left iliac crest (Figure 1). The table can then be rotated so the patient is flat for placement of the axillofemoral bypass or rotated to a full flank position to obtain retroperitoneal aortic exposure. The field, which is prepped and draped, includes the left arm, shoulder, axilla, and hemithorax, and the entire abdomen and both groins to the mid thigh. The retroperitoneal space is developed using the technique initially described by Gaur.‘” An incision is made in the mid-axillary line just anterior to the tip of the 12th rib. Blunt dissection is performed to enter the retroperitoneal space. A balloon trocar is placed through the incision into the retroperitoneal space and inflated to dissect an operating space. The balloon trocar is replaced with a lo-mm operative trocar and t-he retroperitoneum is insufflated to between 12 and 15 mm Hg. Three accessory lo-mm trocars are placed into the retroperitoneal space in a diamond configuration as shown in Figure 1. Anterior and medial retraction of the left kidney allows the infrarenal aorta to be dissected so that it can be encircled just proximal to the aneurysm with a l-cm-wide strip of polytetrafluoroethylene (ePTFE) that is 0.4 mm in thickness. Dissection around the left common iliac artery is performed just distal to the extent of the aneurysm if it involves the iliac artery. The iliac is then encircled with ePTFE. The pneumoretroperitoneum is released and the trocars are left in place. The operating table is then rotated posteriorly so that the patient is supine. Standard incisions are made for the axillofemoral bypass, which is done using an externally supported g-mm ePTFE graft. The graft is tunneled slightly anterior to the midaxillary line to avoid the trocar sites. Prior to arterial clamping, local, rather than systemic, heparin is used in anticipation of the aortic stapling. During infusion of the heparinized saline into the subclavian artery, care must be taken to ensure that no air is introduced. After flow is reestablished through the axillofemoral bypass graft, the right groin incision is extended cephalad above the inguinal ligament to allow retroperitoneal exposure of the iliac artery. The distal right common iliac artery is stapled using a TA stapler (US Surgical, Norwalk, Connecticut) with 4.8-mm vascular staple load placed over a 0.4-mm0002-961 O/96/$1 PII SOOO2-9610(96)00200-0

5.00

363

Pledgened Staple Line

Figure 1. (A and B) A diagramatic representation of the patient’s position on the operating room table. (C) A diagramatic representation of the trocar sites showing the initial trocar position just anterior to the 12th rib.

Figure 2. A diagramatic aorta incorporating the staple line.

thick strip of ePTFE to obtain a pledgetted suture line (Figure 2). The patient is rotated to the flank position and the pneumoretroperitoneum is re-established. The initial lo-mm trocar is replaced with a 15-mm trocar to accommodate the stapler. The stapler is then aligned across the aorta over the ePTFE to form a pledgetted staple line. The distal end of the stapler must be visualized with an angled viewing scope to ensure that no other structures are being incorporated into the staple line. The proximal aorta is stapled followed by stapling the left common iliac artery distal to the aneurysm. The pneumoretroperitoneum is released and all trocar sites are closed in layers. The patient is returned to a supine position and all incisions are closed. The completed procedure is diagrammed in Figure 3.

representation of the stapler around the ePTFE as a pledget and the completed

/

COMMENTS As with any new procedure, problems will be encountered that could not be anticipated by swine or cadaver studies. Despite performing aortic stapling in vivo in 16 swine and 10 fresh cadavers, a patient’s right renal artery, which coursed downward along the aorta, was injured with the tip of the stapler. This was easily recognized in the postoperative period since this was the patient’s only functioning kidney. He was returned to the operating room and the renal artery was explored through a right flank incision. The injured segment of the artery was repaired with a vein interposition. The patient’s renal function returned to baseline levels (preoperative creatinine, 2.6 mg/dL; postoperative creatinine, 2.9 mg/ dL). This was a significant complication, which we believe could have been avoided had we used an angled scope (30”) to visualize the distal tip of the stapler. The staple lines using ePTFE pledgets were quickly applied once the dissection was completed. This technique was developed after extensive in vitro experience with cadaveric human aortas and in vivo experience with pigs. The strength of these staple lines was tested on diseased cadaveric aortas and was found to withstand pressures in excess of 250 mm Hg. Despite the diseased nature of these aortas, a single 2-mm leak was noted through the suture line in 364

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Figure 3. A diagramatic representation of the completed aortic exclusion and axillobifemoral bypass reconstruction. (Staple lines are represented by the black lines across the vessels.)

one out of 10 aortas. Our initial experience with stapling of the pig aorta demonstrated that the pledgetted staple line was necessary to achieve complete hemostasis. At 18month follow-up of our patient, CT scan demonstrates a decrease in aneurysm size and there is no blood flow noted within the aneurysmal segment. The procedure remains technically difficult. One of the limitations at the present time is inadequate laparoscopic instrumentation for aortic procedures, especially for dissection and control of the aorta itself. We believe the development of gasless laparoscopy is an important advance, as OCTOBER

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it may allow us to use standard instruments for aortic and iliac dissection. Our experience suggests that the CO2 insufflation is particularly useful in developing the retroperitoneal space and minimizing bleeding. Thereafter, conversion to the gasless technique would allow the use of standard instruments for aortic and iliac dissection and control. Morbidity of standard graft replacement for AAA is significant.’ Minimally invasive surgery has been shown to reduce morbidity and postoperative recovery time of cholecystectomy, evaluation of abdominal trauma, and Nissen fundoplication.7 Although the operative time for this new approach is longer than the standard procedure, the absence of any ischemic period and the avoidance of a large abdominal incision should reduce the postoperative ileus and expedite return to normal activity. While this is a technically challenging procedure, we believe it to be far simpler than techniques that attempt laparoscopic placement of aortic grafts. The occasional difficulty of graft placement using standard open procedures suggests that laparoscopic suturing of graft15will not be widely adaptable without new and innovative suturing techniques. The role of minimally invasive surgery in the treatment of aneurysmal aortic disease may eventually combine endoluminal and laparoscopic techniques. Although work remains to be done in refinement of techniques, we believe this report clearly demonstrates the feasibility of video-assisted AAA exclusion. The potential for a brief hospital stay and early return to activities may allow this procedure to be extended to better risk patients in the future.

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REFERENCES 1. Katz DJ, Stanley JC, Zelenock GA. operative mortality rates for intact and ruptured abdommal aortlc aneurysms in Michigan: an 11-year statewlde experience. .I Vctsc Surg. 1994;19:804815. 2. Hollier L, Tayl. 3. VanRamshursr B, Vander-Griend R, Eikelboom BC. Survival and life quality after surgery for ruptured abdominal aneurysm. In: Greenhalgh RM. Mannick JA, Powell JT, eds. The Cnuse and Manuge77unt of Aneurysms. London: W.B. Saunders Company, 1990:433-440. 4. Blaisdell F, Hall .4, Thomas A. Liratlon treatment of abdominal aortic aneurysm. Am J Surg. 1965;109:560-545. 5. Pevic WC, Holcroft JW, Blaisdell FW. Ligation and extraanatomic arterial reconstruction for the treatment of aneurysms of the abdominal aorta. J Vusc Surg. 1994;20:629-636. 6. Karmody A, Leather R, Goldman M. et al. The current position of nonresective treiltment for abdominal aortic aneurysm. Surgery 1983;94:591-597. 7. Soper NJ, Brunt LM, Kerbl K. Lapanxcopic general surgery. NE/M. 1994;330:409-419. 8. Berens ES, Herder JR. Laparoscopic vascular surgery: four case reports. J Vast Surg. 1995;22:73-79. 9. Dion YM, Kathouda N, R ou I eau C. Ancom A. Laparoscopyassisted aortobifemoral bypass. Surg Z.@unrsc En&c. 1993;3:425429. 10. Gaur DD. Laparoscopic operative retn)peritoneoscopy: use of a new device. J Ural. 1992;148:1137--1139.

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