The majority of adrenalectomies are currently performed using robotic and laparoscopic approaches. Surgery for the adrenal gland truly reaps the benefits of minimally invasive techniques because of location and anatomy. There is continued development of new laparoscopic and robotic approaches, but many are still under evaluation. Despite these advances, open surgery remains a critical approach for certain indications, including large adrenal adenomas, caval involvement, need for concurrent abdominal procedures, anatomic concerns, primary adrenal cancer, and some pheochromocytomas. When only considering benign adrenal pathology, robotic surgery is emerging as the new gold standard approach ( Box 31.1 ).
Greater than 5 cm adrenal incidentaloma
For successful adrenal surgery, the surgeon must have thorough anatomic knowledge and perform a careful preoperative workup to obtain a diagnosis. The adrenal glands have important relationships to surrounding organs ( Fig. 31.1 ). Variable distance between the adrenal gland and kidney can make dissection challenging, especially in obese patients. The anterior and lateral right adrenal gland usually abuts the inferior vena cava and inferior-posterior surface of the liver, and the anterior and medial left adrenal gland usually is covered by the pancreas and splenic vein ( Fig. 31.2 ). Thus, these organs can be exposed while remaining extraperitoneal by lifting the liver or spleen anteriorly ( Fig. 31.3 ). The posterior surface of both adrenals is in contact with the posterior diaphragm. The adrenal glands lie in the retroperitoneal space with the peritoneal membrane, fusion fascia, and Gerota fascia overlying anteriorly, and the lateroconal fascia overlying posteriorly ( Fig. 31.4 ). These layers are incised for transperitoneal (see Fig. 31.4, A ) and retroperitoneal (see Fig. 31.4, B ) approaches, respectively. The inferior lumbar triangle is a useful landmark used in the retroperitoneal approach and is bound by the iliac crest inferiorly, external oblique muscle anteriorly, and latissimus dorsi posteriorly.
There is an intricate vascular supply to the adrenal glands ( Fig. 31.5 ). The inferior phrenic artery is the main blood supply in adults, with additional branches from the aorta and the renal artery ( Fig. 31.6 ). There are many small perforating arteries, except on the anterior and posterior surfaces. The right adrenal vein, a common source of very troublesome bleeding, is short and fragile. This can rarely merge with a hepatic vein. Small right-sided vessels from the aorta emerge from behind the inferior vena cava as the right middle adrenal artery (see Fig. 31.5 ), entering the gland medially. Care must be taken to control and keep these vessels from tearing and bleeding behind the vena cava. The confluence of left adrenal and renal veins is often just slightly medial and opposite the gonadal vein, just lateral to the renal vein crossing the aorta. There is rarely a second small left adrenal vein that drains laterally into the renal vein. Injury to the left intercommunicating vein can occur as it courses medially near the medial aspect of the adrenal gland ( Fig. 31.7 ). The apical branch of the renal artery to the upper pole of the kidney can be mistaken for an artery to the adrenal gland, leading to inadvertent ligation (see Fig. 31.6 ).
Preoperative Preparation and Planning
Most adrenal lesions are noted incidentally on computed tomography (CT) imaging and require further workup to carefully assess for underlying pathology and prepare the patient for surgery when indicated. CT imaging is generally sufficient to assess the size, anatomy, and Hounsfield units of an adrenal mass. Some radiologists recommend magnetic resonance imaging (MRI) to further delineate anatomy. Precontrast negative Hounsfield units can diagnose benign myelolipoma, which does not require resection. Precontrast 10 Hounsfield units or less indicates benign adenoma, but pheochromocytoma or adrenocortical carcinomas are generally greater than 30 Hounsfield units. Larger adrenal masses that are greater than 5 cm are at increased risk of being adrenal carcinoma, which is discussed in greater detail in Chapter 32 . Approximately 10% to 20% of adrenal lesions have hormonal activity, which can be occult, and thus metabolic evaluation is mandatory.
The full approach to the endocrine evaluation for an adrenal mass is beyond the scope of this chapter. A brief overview of this assessment follows. Pheochromocytoma is the most important pathology to rule out during workup of an adrenal mass. Although they can present with classic symptoms, including sustained hypertension, palpitations, and headache, they are often indolent. Evaluation includes checking plasma-free metanephrine and normetanephrines, although 24-hour total urinary metanephrines and fractionated catecholamines are acceptable as well. MRI or metaiodobenzylguanidine (MIBG) scan may be considered to assess local anatomy and for distant metastases. With proper perioperative management, recent series of pheochromocytomas have shown a mortality rate of less than 3%. Phenoxybenzamine to block α-adrenergic receptors should be started 2 weeks before surgery, with progressively increased dosing. If tachyarrhythmia occurs, beta-blockers may be initiated after alpha blockade. Some experts advocate use of calcium channel blockers instead of alpha-blockers. Finally, dehydration from chronic vasoconstriction must be replenished. Skilled and experienced anesthetic management is of the utmost importance. The surgical approach should be modified for early control of the adrenal vein, with minimal manipulation of the adrenal gland and tumor tissue. Patients need close monitoring and treatment for intraoperative hypertension during adrenal manipulation, as well as rebound hypotension after control of the adrenal vein. Close communication with anesthesiology and all operating room personnel during adrenalectomy of these lesions is critical. Postoperatively, close cardiopulmonary monitoring in an intensive care unit is recommended until the effects of phenoxybenzamine completely wear off.
Cushing syndrome results from excess cortisol production by the adrenal gland. Patients can present with physical stigmata of excess cortisol, including virilization, weight gain, central obesity, and fatigue. Physical examination may reveal hypertension, moon facies, facial plethora, hirsutism, and abdominal striae. Workup includes an overnight low-dose dexamethasone suppression test (2 mg/day), late night salivary cortisol test, or 24-hour urinary-free cortisol evaluation. A suppressed corticotropin level suggests Cushing syndrome from hypersecretion of cortisol from an adrenal adenoma rather than Cushing disease caused by excess corticotropin production from a pituitary adenoma or an ectopic source. After diagnosis, electrolyte abnormalities and hyperglycemia must be corrected. Stress dose steroids should be administered in the perioperative period.
Patients with hyperaldosteronism may be asymptomatic or present with hypertension. Electrolyte abnormalities include hypokalemia, elevated aldosterone with concurrent hyponatremia, and alkalosis, although many patients are normokalemic. It is important to discontinue potassium sparing and mineralocorticoid receptor blocking diuretics 6 weeks before testing. A positive screen is an elevated morning aldosterone-to-renin ratio in the presence of elevated aldosterone level. This should be confirmed with salt loading followed by a 24-hour urine study. CT and adrenal vein sampling can be used to localize hyperaldosteronism and assess for bilateral adrenal hyperplasia. Potassium repletion and administration of a potassium sparing diuretic should be performed perioperatively.
Patient Positioning, Surgical Incision, and Operative Techniques
Several surgical principles should be upheld regardless of approach. Visualization may be difficult because of the deep-seated location of the adrenals and should be consciously maintained throughout the procedure. When treating obese patients with minimally invasive approaches, additional ports can aid with exposure. During laparoscopic cases, we prefer using cutting and coagulation instruments such as the harmonic scalpel, which is very helpful for the dissection and hemostasis of vasculature embedded in retroperitoneal fat. For open cases, headlights can be worn by the surgeon and assistant for maximal light exposure.
In general, dissection of the adrenal should begin at the superior and medial borders of the gland because this allows retraction en bloc with the kidney. The avascular anterior and posterior aspects of the gland allow for subsequent inferior mobilization to aid exposure of the adrenal vein. Care must be taken to avoid direct grasping and manipulation of the gland; rather, the surrounding fat or attached structures should be gently retracted using a blunt instrument. This is especially true for pheochromocytoma, in which the steps of the procedure are altered to allow for early control of the adrenal vein prior to manipulation of the adrenal gland. Partial adrenalectomy can be performed using any approach and is generally used for bilateral lesions or in a solitary adrenal gland. In this situation, hemostasis is best achieved through judicious use of GIA stapling, suturing, and generous use of a bipolar device because of the adrenal gland’s high vascularity.
Choice of Surgical Approach
There are many considerations when choosing type of approach. This decision depends on the etiology of the adrenal disorder, size of the adrenal lesion, and body habitus. The optimal approach is also based on surgeon experience, proficiency, and preference. Robotic surgery is currently the most common technique for small localized benign lesions, with numerous comparative studies showing safety and efficacy with less morbidity for laparoscopic and robotic approaches compared with open approaches. Advantages of the robotic-assisted system over conventional laparoscopy are well established and include stereoscopic vision, greater range of motion, scaled movements enabling precise tissue handling, and a shorter learning curve. The indications for robotic adrenalectomy are identical to those for laparoscopic adrenalectomy, although robotic surgery can generally be used for more challenging anatomy. Considering laparoscopic procedures, there are similar outcomes when comparing intraperitoneal and retroperitoneal laparoscopic approaches. Despite the prevalence of minimally invasive techniques, a level of confidence and proficiency for the open approach must be maintained in the event of conversion to open surgery. Very large tumors are ideally suited to an open thoracoabdominal approach. Bilateral lesions can be visualized and resected with a transabdominal chevron incision or laparoscopic and robotic approaches with repositioning.
In the current era of widespread minimally invasive technologies, the open approach to adrenal surgery should be reserved for very large tumors because they confer significant postoperative morbidity. For the treatment of small benign tumors, we believe it is time to retire these procedures to the history of surgery textbooks, and thus these approaches are not covered in detail in this chapter. Furthermore, because open approaches are rarely used, safe training to achieve proficiency is very difficult.
Robotic-Assisted Laparoscopic Transperitoneal Approach
Positioning, Incisions, and Port Placement
Place a catheter in the patient’s bladder and shave the abdomen if needed. Place the bracket for the airplane-style armboard just superior to the armboard on the side opposite the lesion. Position the patient in the left-side-up lateral decubitus position for left-sided cases and the right-side-up lateral decubitus position for right-sided cases ( Fig. 31.8 ). Depending on central adiposity and lesion size, a horizontal incline between 45 and 70 degrees may be used. Place an axillary roll 2 fingerbreadths below the axilla. Flex the table such that there is slight extension of the flank. Hyperextension is not required because the abdominal wall will continue to extend after pneumoperitoneum is established. Support, pad, and secure the upper arm in a natural and mildly flexed position on the airplane-style armboard. Bend the bottom leg while keeping the upper leg straight. Place several pillows between the knee and ankles to protect pressure points. Secure the lower arm, chest, waist, and knees using towels and cloth tape and double tape the chest and waist (see Fig. 31.8 ). A beanbag positioner or posteriorly placed incline ramps can be used to maintain this position. The table is turned so the patient’s back faces the robot to enable docking.
The da Vinci Surgical System is used in a three- or four-arm configuration per surgeon preference. We use a similar port configuration to what we routinely use for other robotic upper urinary tract procedures. See Fig. 31.9 for right- and left-sided port configurations. Veress needle access ideally should be achieved through the planned final location of the camera port. Make this camera port incision at appropriate length for a 12-mm trocar. Before insufflation, this point is approximately 5 cm below the costal margin along the lateral border of the rectus abdominis muscle or in the midclavicular line in obese patients. The goal with insufflation and expansion of the abdomen is for this point to migrate inferiorly and end up 10 cm below the costal margin (see A in Fig. 31.9 ). In obese patients, use the expected relation to the midclavicular line and costal margin after insufflation rather than strictly relying on the lateral border of the rectus abdominis because this may result in anteromedially displaced ports.
After making the incision, spread the tissue overlying the fascia with a Kelly forceps for visualization and insert a Veress needle through the fascial layers. Aspirate from the Veress needle using a syringe and perform a drop test to confirm free flow of fluid into the peritoneal cavity. If there is concern for abdominal adhesions or a consistently abnormal drop test, switch to an open Hasson technique using a blunt tip trocar or use Palmer’s point for entry, which is 3 cm inferior to the costal margin on the left midclavicular line. Insufflate the abdomen with carbon dioxide to a pneumoperitoneum of 20 mm Hg if tolerated by the patient. Insert a 12-mm trocar for the camera port. Insert a 30-degree, 10-mm rigid laparoscope via this trocar to carefully inspect the peritoneal cavity and examine for injuries upon entry, the presence of adhesions, or signs of metastatic disease. The remaining ports are all placed under direct vision. It is important to note that these are all placed after insufflation. The scope can be rotated to 30 degrees up during port placement if visualization is difficult. An 8-mm robotic port is placed approximately 8 cm superior to the camera port along the lateral border of the rectus muscle or midclavicular line and 2 cm beneath the costal margin (see B in Fig. 31.9 ). A second 8-mm robotic port is placed approximately 8 cm away from the camera port, angled 90 to 120 degrees from the camera port and first robotic port, at least 2 fingerbreadths away from the anterior superior iliac spine (ASIS) (see Fig. 31.9, C ). A 12-mm assistant port (see D in Fig. 31.9 is placed along the low midline just inferior to the umbilicus (see C in Fig. 31.9 ). An optional 8-mm robotic port is placed inferiorly to the camera to assist with retraction of the kidney, either in the midline or along the lateral border of the rectus muscle 10 cm below the assistant port (see E in Fig. 31.9 ). Care is taken to ensure at least 8-cm distance between these ports to prevent clashing. A second 5-mm assistant port may be placed in the midline between the camera port and the upper robotic port (see F in Fig. 31.9 ). The suction and irrigation device is generally used through this port. For right-sided cases, an additional 5-mm port is placed in the midline below the xiphoid process for a liver retractor (see G in Fig. 31.9 ). The second assistant port and the fourth robotic arm are optional, but these additional ports can be especially helpful with obese patients ( Fig. 31.10 ). After all ports are placed, reduce the pneumoperitoneum to 15 mm Hg.
The robot is docked over the patient’s ipsilateral shoulder, and the robotic instruments are inserted. These include monopolar curved scissors in the right robotic arm, bipolar forceps in the left robotic arm, and optional grasping forceps if a four-arm configuration is used. The bedside assistant stands on the side of the patient opposite the mass. Laparoscopic instruments are handled by the bedside assistant and routinely include a suction and irrigation device, a grasper, or a clip applier. In the event of robotic arm collisions caused by poor port positioning, insertion of an additional robotic port in a better location and transfer of the arm will improve efficiency in using the robot.
Surgical Steps: Left
Incise the phrenocolic ligament. Using a combination of blunt and sharp dissection with judicious use of electrocautery, mobilize the colon medially and the spleen cranially. Cut the peritoneum, fusion fascia, and renal fascia and then extend the incision upward along the lateral border of the spleen until the greater curvature of the stomach is exposed ( Fig. 31.11 ). Allow the spleen to fall away in the craniomedial direction by its own gravity until the posterior surface of the pancreas is exposed. Identify the pancreas prospectively because it may be mistaken for the left adrenal gland. It is important to mobilize the spleen to optimize exposure of the adrenal gland so work is performed in a controlled and safe operative field. The goal is to establish adequate exposure, allowing for minimal manipulation of adrenal tissue, thereby minimizing systemic effects from metabolically active lesions.