Adrenalectomy

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CHAPTER 19 Adrenalectomy

E. Carter Paulson, Rachel R. Kelz

Case Study

A 38-year-old female presents to an endocrinologist for evaluation of suspected hyperaldosteronism. Three years earlier, she was diagnosed with hypertension that remains poorly controlled on four antihypertensive medications. She is taking supplemental potassium chloride for recalcitrant hypokalemia. She reports increased fatigue, muscle weakness, and frequent urination.

Physical examination reveals a well-appearing 135-lb woman with a blood pressure of 151/85 mm Hg. Findings on abdominal examination are unremarkable. No masses or striae are appreciated.

She undergoes laboratory testing, which reveals a serum potassium level of 3.1 mEq/L, a serum renin level of 1.31 ng/mL/hr (normal range, 0.15–3.39 ng/mL/hr), and a serum aldosterone level of 82 ng/dL (normal range, 1–16 ng/dL). A computed tomography (CT) scan of the abdomen shows a 2-cm left adrenal mass and a normal-appearing right adrenal gland (Fig. 19-1).

Figure 19-1 CT scan of the abdomen. A left adrenal mass (arrows) is seen.

(From Mettler F: Essentials of Radiology, 2nd ed. Philadelphia, Saunders, 2004.)

BACKGROUND

The adrenal glands are bilateral, retroperitoneal endocrine glands that are located above the kidneys. Each gland consists of a medulla and surrounding cortex. The chromaffin cells of the medulla, which are derived from the neural crest, are the body’s main source of the catecholamine hormones epinephrine and norepinephrine. The adrenal cortex is a site of steroid hormone synthesis. Three distinct regions of the adrenal cortex, the zona glomerulosa, zona fasciculata, and zona reticularis, are responsible for the production of mineralocorticoids (e.g., aldosterone), glucocorticoids (e.g., cortisol), and androgens (e.g., dehydroepiandrosterone), respectively. The cortex is regulated by neuroendocrine hormones secreted by the pituitary gland and hypothalamus and the renin–angiotensin axis.

Tumors arising within the adrenal gland are broadly categorized as either functioning or nonfunctioning. The former secrete one of a number of hormones (Table 19-1). The indications for adrenalectomy, the subject of this chapter, include the treatment of functioning adrenal tumors, suspected primary adrenal malignancies, and in select cases, isolated metastases from extra-adrenal malignancies.

TABLE 19-1 Studies Frequently Obtained in the Evaluation of Functional Adrenal Tumor

Does your patient have a functioning or nonfunctioning adrenal mass?

INDICATIONS FOR ADRENALECTOMY

I. Aldosteronoma

A. Aldosteronomas are the most common functional adrenal tumor and the most common cause of primary hyperaldosteronism (see Table 19-1). Patients classically present with hypertension refractory to multiple medications and hypokalemia. Other symptoms include headaches, polyuria, nocturia, muscle weakness, and cramping.

B. The presence of a unilateral adrenal lesion with biochemical evidence of primary hyperaldosteronism (see Table 19-1) is an indication for adrenalectomy. When imaging shows either bilateral normal glands or bilateral adrenal nodules, adrenal vein sampling may be used to establish the laterality of the lesion. Patients with lateralizing venous sampling benefit from adrenalectomy. Laparoscopic adrenalectomy is the procedure of choice because these lesions are generally small and benign. In contrast, bilateral aldosterone hypersecretion is managed medically (typically with spironolactone).

II. Cortisol-Producing Adenoma

A. Cortisol overproduction (Cushing’s syndrome) can result from increased adrenocorticotropic hormone (ACTH) production by the pituitary gland (Cushing’s disease) or an ectopic source, or from increased adrenal production of cortisol itself. Cushing’s syndrome may present with central obesity, glucose intolerance, hypertension, excess hair growth, osteoporosis, kidney stones, menstrual irregularity, and emotional lability.

Cushing’s syndrome refers to the signs and symptoms of hypercortisolism. When caused by a pituitary adenoma, this syndrome is known as Cushing’s disease.

B. The presence of a unilateral adrenal tumor in patients with biochemical evidence of Cushing’s syndrome (see Table 19-1) is an indication for adrenalectomy. Patients with bilateral adrenal hyperplasia and Cushing’s syndrome require bilateral adrenalectomy. Bilateral adrenalectomy is also indicated in patients in whom trans-sphenoidal surgery for Cushing’s disease is unsuccessful and in some patients with ectopic Cushing’s syndrome when the ACTH-secreting tumor cannot be removed.

III. Pheochromocytoma

A. Pheochromocytomas are rare catecholamine-secreting tumors. The symptoms classically associated with these tumors are attributable to excess adrenaline production and include recurrent episodes of sweating, headache, and anxiety. Excessive catecholamine secretion can also precipitate life-threatening hypertension or cardiac arrhythmias.

B. More than 90% of pheochromocytomas are located within the adrenal glands. Extra-adrenal pheochromocytomas, which develop in the paraganglion chromaffin tissue of the sympathetic nervous system, may occur anywhere from the base of the brain to the urinary bladder. Common locations include the organ of Zuckerkandl (at the origin of the inferior mesenteric artery), the bladder wall, the heart, the mediastinum, and the carotid and glomus jugular bodies.

Pheochromocytoma is known as the 10% tumor: 10% malignant, 10% multiple, 10% bilateral, 10% familial, 10% extra-adrenal, 10% in children.

C. The presence of an adrenal tumor with biochemical evidence of a pheochromocytoma (see Table 19-1) is an indication for adrenalectomy. Manipulation of a pheochromocytoma during surgery can result in the release of large amounts of catecholamines and hemodynamic instability. All patients should receive α- and β-antagonists and volume replacement before surgery. α-Blockade must be initiated before β-blockade because hypertensive crises can result from unopposed alpha stimulation.

α-BLOCKADE MUST BE STARTED BEFORE β-BLOCKADE TO AVOID HYPERTENSIVE CRISES.

IV. Adrenocortical Carcinoma

A. Adrenocortical carcinoma is a rare tumor, affecting one to two persons per 1 million. The median age at diagnosis is 44 years. Between 60% and 80% of these tumors are functional. Nonfunctional tumors often present with symptoms related to local invasion or mass effect, such as abdominal or flank pain. Only 30% of these malignancies are confined to the adrenal gland at the time of diagnosis.

B. Cross-sectional imaging (CT scan and magnetic resonance imaging [MRI]) often localizes the tumor. Radiographic findings that suggest malignancy include large size (most adrenal carcinomas are larger than 6 cm at the time of diagnosis), irregular borders, and invasion into surrounding structures. Radical surgical excision, generally performed using an open approach, is the treatment of choice for patients with localized malignancies and remains the only therapy with which long-term disease-free survival can be achieved.

V. Adrenal Metastases. The adrenal glands are relatively common sites of metastases. Breast, lung, and renal cell cancers; melanomas; and lymphomas may metastasize to the adrenal glands. Surgical resection of solitary adrenal metastases in patients with a long previous disease-free interval and no evidence of extra-adrenal disease results in prolonged survival. Imaging, including positron emission tomography scanning to rule out the presence of other metastatic disease and appropriate laboratory testing to determine the functionality of the lesion, should be performed before resection. If pheochromocytoma is ruled out, fine-needle aspiration under CT or ultrasound guidance may also be useful in making a definitive diagnosis.

FINE-NEEDLE ASPIRATION OF AN UNDIAGNOSED PHEOCHROMOCYTOMA CAN RESULT IN A HYPERTENSIVE CRISIS BECAUSE OF CATECHOLAMINE RELEASE.

VI. Incidentalomas. The term incidentaloma refers to an asymptomatic mass or lesion discovered on routine imaging. Adrenal incidentalomas are noted on up to 5% of all abdominal CT scans. In the absence of a history of malignancy, nonfunctioning lesions smaller than 4 to 5 cm are typically followed with serial imaging (CT scan or MRI). Adrenalectomy is usually recommended for nonfunctioning adrenal masses larger than 5 cm because of the elevated risk of malignancy associated with larger lesions. All functioning incidentalomas should be resected (Fig. 19-2).

Figure 19-2 Algorithm for the evaluation and management of adrenal incidentalomas. ACTH, adrenocorticotropic hormone; CT, computed tomography; FNA, fine-needle aspiration; MRI, magnetic resonance imaging; PAC, plasma aldosterone concentration; PRA, plasma renin activity.

(Adapted from Cameron J: Current Surgical Therapy, 7th ed. Philadelphia, Mosby, 2001.)

PREOPERATIVE EVALUATION

I. Tests of endocrine function include 24-hour urine catecholamines, metanephrines, and cortisol; plasma ACTH, aldosterone, and renin; serum potassium; and dexamethasone suppression tests. These tests distinguish functioning from nonfunctioning masses.

II. Cross-Sectional Imaging. CT scanning and MRI may aid in the localization of adrenal masses and the identification of malignant characteristics. Adrenal lesions that are large (>5 cm in diameter) and have irregular borders are more likely to be malignant. Invasion into surrounding structures is diagnostic of malignancy. These modalities also allow for identification of extra-adrenal disease (e.g., extra-adrenal pheochromocytomas or extra-adrenal metastatic disease).

Does your patient’s adrenal lesion have radiographic features suggesting malignancy?

III. Iodine-131-Metaiodobenzylguanidine (MIBG) Scanning. ¹³¹I-MIBG selectively accumulates in chromaffin cells and may aid in the identification of small, recurrent, or extra-adrenal pheochromocytomas that cannot be localized with CT scanning and MRI.

IV. Adrenal vein sampling is primarily used to differentiate between unilateral hyperaldosteronism and bilateral adrenal hypersecretion. Aldosterone and cortisol levels are measured in venous blood samples from both adrenal veins and the inferior vena cava.

COMPONENTS OF THE PROCEDURE AND APPLIED ANATOMY

See Figure 19-3.

Figure 19-3 Anatomy of the adrenal glands. The adrenal gland receives blood supply from branches of the inferior phrenic arteries (superior suprarenal arteries) and branches of the aorta (middle and inferior suprarenal arteries). The right adrenal vein drains directly into the vena cava, whereas the left adrenal vein drains into the left renal vein.

(From Becker JM, Stucchi AF [eds]: Essentials of Surgery. Philadelphia, Saunders, 2006.)

There are multiple operative approaches to adrenalectomy. Traditionally, adrenal resections were performed in an open fashion through one of four approaches: transabdominal, lateral flank, posterior retroperitoneal, and thoracoabdominal. The laparoscopic approach has largely supplanted the lateral flank and posterior retroperitoneal approaches and is described in detail. The retroperitoneal laparoscopic and open approaches are briefly reviewed.

Preoperative Considerations

I. Urinary catheterization is indicated to decompress the bladder and monitor intraoperative and postoperative volume status.

II. Manipulation of pheochromocytomas can result in the release of catecholamines, which may be accompanied by wide and unpredictable fluctuations in blood pressure. An arterial line, to allow for continuous blood pressure monitoring, should therefore be inserted before resection of a pheochromocytoma.

Patient Positioning and Preparation

I. The patient is placed in the lateral decubitus position, with the side opposite the lesion down (Fig. 19-4).

II. The table is flexed and the patient is placed in a slight reverse Trendelenburg position.

III. The anterior and posterior axillary lines are useful landmarks for port placement and should be marked before the patient is prepped.

IV. The abdomen is prepped to the nipples superiorly, to the anterior superior iliac crest inferiorly, to the umbilicus anteriorly, and to the vertebral column posteriorly.

Figure 19-4 Lateral decubitus position. The patient is placed on a padded mattress. The table is flexed, and the patient is placed in a reverse Trendelenburg position.

(From Townsend CM, Beauchamp RD, Evers BM, Mattox KL [eds]: Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice, 17th ed. Philadelphia, Saunders, 2004.)

Port Placement

I. In general, left adrenalectomy is performed through three operative ports and right adrenalectomy is performed through four operative ports. The additional port on the right side allows for the placement of a liver retractor.

II. Initial access to the abdomen is obtained just medial to the anterior axillary line and lateral to the rectus muscle. This can be accomplished using a “blind” percutaneous technique using a Veress needle or an open technique; the latter is more commonly used.

THE VERESS NEEDLE APPROACH SHOULD NOT BE USED IN PATIENTS WHO HAVE HAD PREVIOUS ABDOMINAL SURGERY.

III. Open Technique for Placement of the First Port

A. A small transverse incision is made just medial to the anterior axillary line five fingerbreadths below the costal margin.

B. The external oblique fascia is exposed after blunt dissection of the subcutaneous soft tissue. The fascia is incised.

C. The three muscle layers underlying the fascia are bluntly dissected to reveal the transversalis fascia.

D. The posterior fascia and underlying peritoneum are divided under direct vision.

E. Sutures are placed in the fascia to secure the port and to minimize CO₂ leakage and loss of pneumoperitoneum.

F. The port is inserted through the incision using a blunt-tipped trocar.

G. CO₂ is insufflated through the port. The abdomen should distend symmetrically and become uniformly tympanic. If this does not happen, extraperitoneal port placement should be suspected.

H. The laparoscope is inserted through the port, and the peritoneal cavity is surveyed.

IV. Placement of the Remaining Ports

A. The remaining ports are inserted under direct intra-abdominal visualization. Cutting (sharp) introducers are used to penetrate the fascia and enter the peritoneal cavity.

B. The additional ports are placed, evenly spaced at least 5 cm apart, along the costal margin (Fig. 19-5).

C. On the left side, the splenic flexure of the colon is mobilized before insertion of lateral ports to reduce the risk of colonic injury.

Figure 19-5 Port placement for laparoscopic adrenalectomy.

(From Cameron J: Current Surgical Therapy, 7th ed. Philadelphia, Mosby, 2001.)

Right Adrenalectomy

I. Exposure

A. The right triangular ligament of the liver is divided using electrocautery to allow for retraction of the right liver lobe and exposure of the inferior vena cava (IVC) and right adrenal gland (Fig. 19-6).

B. A liver retractor is inserted through the most medial port to retract the right lobe of the liver medially.

C. An atraumatic grasper is used to apply lateral traction to the adrenal gland.

D. Electrocautery is used to create a plane between the medial edge of the gland and the lateral border of the IVC, exposing the right adrenal vein.

II. Isolation and Division of the Right Adrenal Vein

A. A dissector is used to expose the right adrenal vein circumferentially.

B. Three surgical clips, two placed proximally on the IVC side and one placed distally, are applied to the vein.

C. The vein is divided sharply between the proximal and distal clips.

III. Mobilization of the Right Adrenal Gland

A. Dissection is continued along the edge of the gland inferiorly and superiorly.

B. Most small arteries entering the gland can be cauterized; however, larger branches should be clipped.

C. The inferior dissection proceeds in a medial to lateral direction. Care should be taken to stay close to the edge of the adrenal gland to avoid injuring branches of the renal vessels.

D. Superiorly, dissection continues in the relatively avascular plane between the superior pole of the gland and the musculature of the diaphragm.

E. Posteriorly, the avascular attachments to the back muscles and retroperitoneal fat can be divided with electrocautery.

F. Once it is fully mobilized, the specimen is placed in an impermeable bag.

G. The retroperitoneum is irrigated and inspected for hemostasis.

IV. Specimen Extraction

A. The specimen is extracted through one of the port sites.

B. For large tumors, a separate incision (umbilical or suprapubic) may facilitate specimen removal.

C. In general, malignant tumors or metastatic lesions should be removed intact to allow for thorough pathologic evaluation.

Figure 19-6 A, The right triangular ligament of the liver is divided to allow for medial rotation of the right lobe. B, The medial border of the adrenal is dissected to expose the inferior vena cava and right adrenal vein.

(From Brunt LM: Laparoscopic adrenalectomy. In Eubanks WS, Swanstrom LL, Soper NJ [eds]: Mastery of Endoscopic and Laparoscopic Surgery. Philadelphia, Lippincott Williams & Wilkins, 2000, p 325.)

Left Adrenalectomy

I. Exposure

A. The splenic flexure of the colon is mobilized by dividing the splenocolic ligament, allowing retraction of the colon away from the left kidney and the inferior pole of the spleen (Fig. 19-7).

B. The splenorenal ligament (between the inferior pole of the spleen and the superior pole of the kidney) is divided close to the spleen to allow medial rotation of the spleen and access to the left retroperitoneum.

C. The medial and lateral borders of the adrenal gland are defined using electrocautery dissection.

D. Dissection is continued inferiorly to identify the left adrenal vein, a branch of the left renal vein, which exits the gland in an inferiomedial position.

II. Isolation and Division of the Left Adrenal Vein

A. A dissector is used to expose the left adrenal vein circumferentially.

B. The vein is doubly clipped and divided.

III. Mobilization and Detachment of the Left Adrenal Gland

A. Dissection is continued along the medial and lateral edges of the gland.

B. The superior and posterior attachments to the diaphragm and retroperitoneal fat are divided.

C. Once the dissection is complete, the specimen is placed in an impermeable bag and the retroperitoneum is irrigated and inspected for hemostasis.

IV. Specimen Extraction

A. The specimen is extracted in the same manner described for the right adrenal gland.

B. Of note, care should be taken to inspect the tail of the pancreas. If there is concern that the parenchyma of the pancreas was injured, a closed-suction drain should be left in place.

Figure 19-7 A, The splenocolic ligament is divided (dotted line), followed by division of the splenorenal ligament (dashed line). B, The spleen is rotated medially, and the kidney is retracted laterally. The adrenal vein is ligated at the inferomedial border of the adrenal with endoscopic clips.

(From Brunt LM: Laparoscopic adrenalectomy. In Eubanks WS, Swanstrom LL, Soper NJ [eds]: Mastery of Endoscopic and Laparoscopic Surgery. Philadelphia, Lippincott Williams & Wilkins, 2000, pp 326, 327.)

Other Operative Approaches

I. The posterior retroperitoneal laparoscopic approach is useful for bilateral adrenalectomy or in patients who have had previous abdominal surgery. The procedure is performed with the patient in prone position. The initial port is placed just inferior to the tip of the 12th rib into the retroperitoneum. A balloon dissector is used to expose the retroperitoneal space. Two additional trocars are placed: one at the edge of the erectus spinus muscle and one at the posterior axillary line. The adrenal gland is identified above the kidney. Exposure and dissection of the adrenal glands proceed in the same fashion as for the transabdominal lateral laparoscopic approach.

II. The open transabdominal approach, which allows access to both adrenal glands and the entire abdominal cavity, is the preferred method for tumors too large to be removed laparoscopically and for all invasive adrenal tumors. This approach may be performed through a subcostal or midline incision. Exposure and dissection proceed as described for laparoscopic adrenalectomy.

III. The open posterior retroperitoneal approach, performed through a hockey-stick incision on the back (Fig. 19-8), has been almost entirely supplanted by laparoscopic approaches. This approach allows for visualization of both adrenal glands, but provides limited working space. Furthermore, the incision is not well tolerated by patients.

IV. The open lateral retroperitoneal approach is sometimes preferred in obese patients or patients with large tumors. As with the lateral laparoscopic approach, the patient is placed in the lateral decubitus position, with the table flexed. A subcostal or intercostal incision centered at the midaxillary line is used. Like the posterior open method, this approach has been largely supplanted by laparoscopic resection.

V. The open thoracoabdominal approach is performed through an incision that extends from the abdominal wall to the eighth intercostal space and provides exposure to both the abdominal and chest cavities. This exposure allows for control of the vena cava, which is sometimes necessary for the safe resection of large adrenal tumors or those that involves the vena cava.

Figure 19-8 Incision for open posterior approach to adrenalectomy (dashed line). The incision is extended inferiorly and laterally from the tenth rib to the posterior iliac crest.

(From Townsend CM, Beauchamp RD, Evers BM, Mattox KL [eds]: Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice,17th ed. Philadelphia, Saunders, 2004.)