Overview
Definition:
The retroperitoneal approach to the abdominal aorta involves accessing the aorta by dissecting through the retroperitoneal space, posterior to the peritoneum
This contrasts with transperitoneal approaches
It offers advantages for certain aortic pathologies, particularly infrarenal abdominal aortic aneurysms (AAA) and aortic occlusive disease, by providing direct visualization and control of the aorta and its branches with minimal bowel manipulation.
Epidemiology:
Abdominal aortic aneurysms are the 15th leading cause of death in men over 65 in the US
The prevalence increases with age and risk factors like smoking and hypertension
Surgical repair, often via retroperitoneal or transperitoneal routes, is a common intervention
The choice of approach depends on surgeon preference, patient anatomy, and the specific pathology.
Clinical Significance:
This approach is crucial for managing life-threatening conditions such as ruptured AAA, symptomatic AAA, and aortoiliac occlusive disease
Understanding its anatomy, techniques, and potential complications is vital for surgical residents preparing for DNB and NEET SS examinations, as it directly impacts patient outcomes and surgical decision-making.
Indications
Specific Conditions:
Infrarenal abdominal aortic aneurysms (AAA)
Juxtarenal or suprarenal AAA when feasible via this approach
Aortoiliac occlusive disease
Chronic mesenteric ischemia due to visceral artery stenosis
Trauma to the abdominal aorta
Infected AAA where avoiding bowel contamination is paramount.
Patient Factors:
Previous abdominal surgery with extensive adhesions making transperitoneal approach difficult
Significant comorbidities where minimizing bowel handling and operative time is beneficial
Obesity may favor a retroperitoneal approach for better exposure of the aorta.
Contraindications:
Absolute contraindications are rare
Relative contraindications include extensive retroperitoneal fibrosis or malignancy, and significant coagulopathy
Acute visceral ischemia may necessitate a transperitoneal approach for direct visceral artery access.
Preoperative Preparation
Patient Evaluation:
Comprehensive cardiovascular assessment, including ECG, echocardiogram, and stress testing if indicated
Pulmonary function tests
Renal function assessment
Hematological profile including coagulation status
Glycemic control in diabetic patients.
Imaging:
CT angiography (CTA) is essential for detailed anatomical assessment of the aneurysm or stenosis, including neck length and diameter, relationship to renal arteries and iliac vessels, presence of thrombus, and calcification
Duplex ultrasound may be used for initial screening or follow-up.
Anesthesia Considerations:
General anesthesia with endotracheal intubation is standard
Invasive hemodynamic monitoring, including arterial line and central venous catheter, is usually required
Epidural analgesia can be considered for postoperative pain management
Blood products should be readily available.
Procedure Steps
Patient Positioning:
Patient is placed in a lateral decubitus position, typically right lateral decubitus for left flank approach or left lateral decubitus for right flank approach
The ipsilateral flank is elevated to open the retroperitoneal space.
Incision:
A flank incision is made in the lumbar region, typically 2-3 cm above the iliac crest, extending anteriorly and superiorly
The skin, subcutaneous tissue, and muscles (obliques, transversus abdominis) are divided
The retroperitoneal space is entered anterior to the quadratus lumborum muscle.
Dissection And Exposure:
The peritoneum is mobilized anteriorly, exposing the colon, spleen (if left-sided), pancreas, and duodenum
Careful dissection identifies the aorta and its surrounding structures
Ligation of lumbar arteries and veins may be necessary for adequate exposure
Mobilization of the left renal vein is often required for suprarenal control.
Aortic Control:
Proximal control of the aorta is achieved using vascular clamps, typically distal to the superior mesenteric artery and renal arteries for infrarenal aneurysms
Distal control is achieved at the aortoiliac bifurcation or common iliac arteries
Careful attention is paid to avoid injury to the vena cava and ureters.
Aneurysm Repair:
For AAA repair, an aortobifemoral or aortounilial graft is typically used
The aorta is opened longitudinally, the sac is inspected, and the graft is anastomosed proximally and distally
For occlusive disease, bypass grafting or endarterectomy is performed
Hemostasis is meticulously achieved.
Postoperative Care
Monitoring:
Continuous monitoring of vital signs, urine output, and hemodynamic status
Fluid management to maintain adequate renal perfusion
Pain management with analgesics, including patient-controlled analgesia (PCA) or epidural anesthesia
Serial abdominal examinations for distension or tenderness.
Complication Surveillance:
Close monitoring for signs of bleeding (hematoma formation, hemodynamic instability), graft infection, limb ischemia, or bowel compromise
Laboratory monitoring of renal function, electrolytes, and complete blood count
Early ambulation to prevent deep vein thrombosis and pulmonary complications.
Discharge Planning:
Patient education on wound care, activity restrictions, signs and symptoms of complications, and medication adherence
Follow-up appointments for graft surveillance with duplex ultrasound or CTA as per protocol
Dietary recommendations and smoking cessation advice.
Complications
Early Complications:
Hemorrhage from lumbar vessels or aortic stump
Injury to vena cava, ureter, or bowel
Graft dehiscence or infection
Ischemia of distal extremities or abdominal organs
Renal failure
Ileus.
Late Complications:
Graft infection
Pseudoaneurysm formation at anastomotic sites
Graft occlusion
Endoleak (in endovascular repairs, though less common with open)
Chronic mesenteric ischemia
Lumbar pseudoaneurysm formation.
Prevention Strategies:
Meticulous surgical technique, careful dissection, secure anastomoses, adequate hemostasis
Perioperative antibiotic prophylaxis
Careful identification and protection of adjacent structures
Preoperative optimization of patient comorbidities
Vigilant postoperative monitoring.
Key Points
Exam Focus:
Understanding the anatomical landmarks for dissection
Indications for retroperitoneal vs
transperitoneal approach
Management of lumbar vessels and renal vein
Crucial steps for proximal and distal aortic control
Common complications and their management strategies.
Clinical Pearls:
The right lateral decubitus position provides excellent exposure of the infrarenal aorta and iliacs with less retraction of the colon
Left renal vein often needs to be mobilized for suprarenal control
Always confirm adequate proximal and distal control before opening the aorta
Meticulous hemostasis is critical.
Common Mistakes:
Injury to the inferior vena cava during mobilization
Inadequate proximal or distal aortic control leading to uncontrolled hemorrhage
Incomplete ligation of lumbar vessels causing postoperative retroperitoneal hematoma
Overlooking injury to the ureter or bowel
Insufficient mobilization of the left renal vein for suprarenal clamping.