Retroperitoneal Approach via Paramedian Incision for Aortoiliac Occlusive Disease

Abstract

Aortoiliac occlusive disease is a frequently encountered occlusive arterial disease. Different surgical approaches to the infrarenal abdominal aorta have been reported. We retrospectively studied the postoperative outcomes of patients who were treated for aortoiliac occlusive disease via a retroperitoneal versus a transperitoneal surgical approach.

From January 2005 through May 2009, 47 patients underwent surgery at our hospital for the correction of aortoiliac occlusive disease: 30 via a paramedian incision and retroperitoneal approach, and 17 via a midline sternotomy and transperitoneal approach. In the retroperitoneal group, the surgical procedures involved iliofemoral bypass in 15 patients, aortofemoral bypass in 12, aortoiliac bypass in 2, and aortobifemoral bypass in 1. All 17 patients in the transperitoneal group underwent aortobifemoral bypass. The preoperative characteristics and perioperative data of the patients were analyzed. We believe that the retroperitoneal aortoiliac approach with a paramedian incision may be considered as a surgical option for aortoiliac revascularization.

Aortoiliac occlusive disease is among the most common forms of chronic obliterative atherosclerosis. The atherosclerotic process typically develops around the aortic bifurcation and occurs to varying degrees in patients who show symptoms of arterial insufficiency.¹ Standards regarding the treatment of aortoiliac occlusive disease were established in the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II), published in 2007.² Recently, aortic procedures have been performed via laparoscopic surgery, because minimally invasive techniques produce results that are comparable with those of conventional techniques.^3–5

Here, we discuss our retrospective analysis of the surgical outcomes of patients who underwent paramedian retroperitoneal surgical approaches versus midline transperitoneal approaches in the treatment of aortoiliac occlusive disease.

Patients and Methods

We studied the cases of 47 patients (46 of whom were men) who were operated upon for aortoiliac occlusive disease from January 2005 through May 2009. Thirty of the patients had undergone surgery via a paramedian incision and retroperitoneal approach, and the other 17 via a midline incision and transperitoneal approach (Table I). In both groups, risk factors were associated with peripheral vascular disease.

TABLE I. Preoperative Characteristics of the Patients

The surgical indications were to relieve ischemic pain, heal ischemic ulcers, prevent limb loss, improve function and quality of life, and prolong survival, as described in the TASC II consensus.² The major indication for taking the retroperitoneal approach was unilateral aortoiliac occlusive disease; for taking the transperitoneal approach, the chief indication was bilateral aortoiliac occlusive disease.

The patients who had multiple risk factors and the patients who had symptoms of coronary artery disease (angina, ischemic changes upon electrocardiography, ischemia upon dipyridamole thallium scintigraphy, or left ventricular wall-motion abnormalities upon stress echocardiography) were evaluated by means of preoperative coronary angiography. Angiography was performed in 13 patients in the retroperitoneal group and in 8 patients in the transperitoneal group. One patient in each group underwent coronary artery bypass surgery, and 2 in the retroperitoneal group underwent coronary artery angioplasty. The remaining 10 retroperitoneal and 7 transperitoneal patients had nonsignificant coronary lesions and received medical therapy.

All but 8 patients in the retroperitoneal group and 2 patients in the transperitoneal group were operated upon solely because of the results of computed tomographic angiography. One patient was examined preoperatively by both peripheral and computed tomographic angiography (Figs. 1 and 2). Iliac lesions were not considered appropriate for treatment via percutaneous transluminal coronary angioplasty. Decisions to perform surgery were made after consultation with radiologists. Patients with unilateral lesions, previous abdominal surgery, or severe chronic obstructive pulmonary disease (COPD) that might complicate general anesthesia were selected for revascularization via the retroperitoneal approach. Early during the study period, patients who had bilateral lesions were selected for the transperitoneal approach. As our surgical experience increased, bilateral lesions were more often treated via the retroperitoneal approach.

Fig. 1 Preoperative peripheral angiography shows a lesion in the left iliac artery.

Fig. 2 Preoperative computed tomographic angiography shows A) the aortoiliac arterial segment and B) the femorodistal arterial segment in the same patient as shown above.

Surgical Techniques

All operations were performed with the patients under general anesthesia, except for 5 in the retroperitoneal group. These 5 patients were given regional epidural and spinal anesthesia. The femoral artery was exposed first in all patients in whom aortofemoral or iliofemoral bypass was planned. Paramedian incisions were performed in the 30 patients in the retroperitoneal group, via a vertical 7- to 8-cm incision approximately 6 cm to the left or right of midline, extending from a few centimeters above the umbilicus to just above the symphysis pubis (Fig. 3). The anterior rectus sheath was incised at the external end of the rectus abdominis muscle, and the posterior rectus sheath was incised above the semilunar line. The retroperitoneal space was then entered in order to attain access to the aorta or the iliac artery. In contrast, the patients in the transperitoneal group underwent a midline laparotomy from above the umbilicus to the symphysis pubis. The aorta was exposed transperitoneally, and bypass surgery was performed after the terminal abdominal aorta or the iliac arteries were exposed.

Fig. 3 Postoperative photograph shows the paramedian surgical incisions.

We preferred 8-mm Dacron expanded-polytetrafluoroethylene grafts and polypropylene sutures for unilateral procedures, and 16- to 18-mm bifurcated Dacron grafts for bilateral procedures. Anticoagulation was accomplished by using 1 mg/kg body weight of heparin until a target activated clotting time of 250 to 350 seconds was achieved. Proximal end-to-side anastomosis was performed first on the side-clamped inflow artery. In the retroperitoneal group, the surgical procedures involved iliofemoral bypass in 15 patients, aortofemoral bypass in 12, aortoiliac bypass in 2, and aortobifemoral bypass in 1 patient. Aortobifemoral bypass was performed in all 17 of the patients in the transperitoneal group. Nine patients in the retroperitoneal group and 7 patients in the transperitoneal group had extensive infrainguinal occlusive disease that necessitated additional femoropopliteal bypass operations (P=0.528).

Statistical Analysis

The preoperative characteristics and perioperative data on the patients were analyzed. Statistical analysis was performed with use of SPSS statistical software version 10.0 (SPSS Inc.; Chicago, Ill). Categorical variables were analyzed via the c ² test. Continuous variables were expressed as mean ± SD and were compared by means of the 2-tailed independent-samples t test. A P value of less than 0.05 was considered to be statistically significant.

Results

Two patients in the retroperitoneal group died postoperatively—1 of myocardial infarction and the other of pulmonary complications. Surgical success was ascertained in all patients by means of physical examination and determination of ankle–brachial indices. The mean length of postoperative hospitalization in the retroperitoneal group was 7.6 ± 3.24 days (range, 4–16 d), versus 12.35 ± 5.75 days (range, 6–24 d) in the transperitoneal group. The mean duration of stay in the intensive care unit (ICU) was 0.66 ± 0.82 days (range, 0–3 d) in the retroperitoneal group versus 1.76 ± 1.2 days (range, 0–4 d) in the transperitoneal group (Table II).

TABLE II. Perioperative and Postoperative Data on the Patients

No intraoperative complications occurred. Six patients required subsequent reoperation: 2 in each group for acute distal embolism to the contralateral limb, and 2 in the retroperitoneal group for distal anastomosis leakage. These were successfully treated upon simple reoperation. All 45 surviving patients were discharged from the hospital on antiplatelet therapy.

Three transperitoneal-approach patients developed distal surgical-site infections, and 1 contracted nosocomial pneumonia. All were treated with parenteral antibiotics. No complications resulted from the incisions.

Graft patency was evaluated by means of physical examination and Doppler ultrasonography. Upon the patients' hospital discharge, primary graft patency was 100%. Follow-up was conducted on 26 patients in the retroperitoneal group for a mean period of 15.9 ± 11.9 months (range, 1–42 mo) and on 14 patients in the transperitoneal group for 10.3 ± 11.5 months (range, 1–40 mo). Four patients in the retroperitoneal group underwent reoperation during the follow-up period: 2 for acute graft occlusion and 2 for femoropopliteal disease. Thrombectomy and femoropopliteal bypass surgery were successfully performed in these patients.

Discussion

In recent years, surgeons have tended to use the retroperitoneal approach for aortic surgery because it may reduce physiologic risks, such as reduction of cardiac stress, respiratory complications, postoperative ileus, and 3rd-space fluid losses.⁶ However, randomized prospective studies have determined no significant differences in outcome. The retroperitoneal approach has proved advantageous in patients with multiple previous intra-abdominal surgical procedures, previous aortic surgery, and other hostile abdominal conditions. A retroperitoneal approach may also be helpful if substantial juxtarenal or pararenal disease requires repair or when concomitant left renal arterial revascularization or other visceral arterial repair is necessary. Technical difficulties occur in obese patients, because access to the right renal artery is poor, and control and repair of the right iliac artery may be difficult through a left retroperitoneal approach.⁷ We did not encounter such complications, because our patients were not morbidly obese.

In a retroperitoneal approach to the infrarenal abdominal aorta, paramedian and flank incisions have both induced atrophy of the anterolateral abdominal muscle (paramedian more so than flank). Multiple cuts in the intercostal nerves probably induce denervation of the rectus abdominis muscle.⁸ None of our patients experienced a complication due to muscle atrophy during the follow-up period.

Recently, laparoscopic surgery has increased in importance, and some institutions have changed to laparoscopic retroperitoneal procedures when an abdominal approach to the aorta is best avoided because of abdominal, cardiac, or pulmonary risks. However, due to a learning curve, laparoscopic operative and clamping times are usually longer than those that are typical in open repair of aortoiliac occlusive disease. Median blood loss is comparable to that of conventional aortic surgery, and body temperature at the end of the operation is better preserved. Nonetheless, laparoscopy does not favorably influence postoperative outcome in patients who are at high surgical risk, except in those who are morbidly obese or who have severe COPD.

Laparoscopy affords rapid postoperative recovery and a reduced incidence of abdominal-wall hernia.⁵ The morbidity and mortality rates in our groups were acceptable. In our series, durations of stay in the ICU and the hospital were significantly higher among the patients in the transperitoneal group, all of whom underwent aortobifemoral bypass because of extensive disease; in contrast, our patients in the retroperitoneal group underwent mostly unilateral revascularization. Controversies surrounding midline laparotomy—prolonged ileus, higher incidence of COPD, longer lengths of stay in the ICU and the hospital, and increased hospitalization costs—are well known.⁹ It is possible to perform aortobifemoral bypass via a left paramedian retroperitoneal approach, as we did in 1 patient in our study group. Another advantage of the retroperitoneal approach is that it can be performed with use of regional anesthesia in patients who are awake (as we did in 5 of our patients), which may shorten their hospital stay.

Although the retroperitoneal approach tends to result in fewer postoperative complications, shorter stays in the hospital and the ICU, and lower costs, patients experience increased long-term incisional pain. No difference has been found in the incidence of incisional bulges or hernias.⁹ Nevertheless, investigators have suggested the use of the retroperitoneal approach for treating infrarenal aortic disease.⁹ Our patients did not experience pain so severe that they required narcotic analgesia. Regional anesthesia may provide postoperative pain relief in patients who are operated upon under epidural anesthesia.

Unilateral aortofemoral–iliofemoral and aortoiliac bypass surgery has an excellent long-term outcome. The retroperitoneal approach with lateral flank incision for unilateral aortoiliac obstructive disease has been suggested as a good alternative to conventional aortobilateral reconstruction in these lesions.¹⁰ The retroperitoneal approach via a paramedian incision affords easy access and rapid exposure of the retroperitoneal vascular structures. Femorofemoral crossover bypass surgery carries the disadvantage of proximal stenosis in the donor iliac vessel, which may jeopardize both extremities¹¹; therefore, this procedure should be reserved for patients who are unsuited to a retroperitoneal approach or who have a short life expectancy.¹²

Arteriosclerosis is frequently a generalized process. Obliterative disease in the aortoiliac segment frequently coexists with disease below the inguinal ligament. However, aortoiliac disease is usually segmentally distributed, and therefore effective treatment is feasible.⁷ In our study, both groups comprised patients who had extensive infrainguinal lesions that were revascularized during additional femoropopliteal bypass procedures. Another consideration is that progression of disease in the aorta from an untreated contralateral iliac artery will necessitate reoperation in some patients who were treated initially with unilateral operations for apparent 1-sided disease; however, the frequency of this occurrence remains controversial.¹³ We did not observe progression of the disease to the contralateral side in the patients who were operated upon for unilateral occlusive disease. However, 1 patient in whom disease progressed to the infrainguinal arteries required revascularization by means of femoropopliteal bypass.

The levels of biochemical markers in both of our study groups were similar, which could lead to the conclusion that both procedures would have resulted in similar outcomes. Although we used no cell-savers in our study population, these may decrease the need for transfusion. In our study, more surgical-site infections were observed in the transperitoneal group, and these probably prolonged the hospitalization durations. Although the comparison of death between the groups was not statistically significant, 2 patients died in the retroperitoneal group. Both were 73 years of age and had several comorbidities.

Distal atheromatous embolism, caused by the placement of side-biting clamps on atheromatous aortas, occurred in 4 patients in the early postoperative period. The complication did not occur when aortas were cross-clamped. Postoperative follow-up in the retroperitoneal group revealed graft occlusions in 2 patients whose superficial femoral arteries were mildly stenotic. The occlusions, which were detected 1 and 2 years postoperatively and were treated by means of thrombectomy, may have been due to end-to-side anastomoses. End-to-end anastomoses would have provided better hemodynamic performance.

Major limitations of this study include the small number of patients in the groups, the inequality of the study subpopulations in number, the limited duration of postoperative follow-up, and (to some extent) the heterogeneity of the groups.

We believe that a retroperitoneal aortoiliac approach with a paramedian incision is a feasible surgical option in the treatment of aortoiliac occlusive disease. The approach incurs few postoperative complications, and it is tolerated well. It can also be applied in patients with bilateral lesions. These advantages have made this our preferred approach in the treatment of most of these lesions.