Surgery of Adrenal Disorders
John A. Libertino, M.D .*
Surgery of the adrenal gland is essentially that of the infradiaphragmatic great vessels and associated viscera, such as the pancreas, liver, and spleen. These structures constitute the greatest technical challenge of adrenal surgery. Historically, urologists, such as Cahill,2, 3 Flint,7-9 and Glenn, 10-13 have contributed greatly to the understanding of adrenal disease and adrenal surgery. They have fostered another generation of adrenal surgeons who maintain an interest in and have developed centers of excellence for the management of patients with adrenal endocrinopathies.
The diagnostic dilemmas confronting our former colleagues have been lessened by recent advances in computed tomography (CT) and radioisotopic scans. The surgical management of patients with adrenal disease depends on the functional nature of the endocrinopathy, a thorough knowledge of adrenal anatomy, and the various surgical approaches to the suprarenal gland.
SURGICAL ANATOMY OF ADRENAL GLAND
The position of the adrenal gland in the retroperitoneum adjacent to the upper pole of the kidneys is constant. The arterial supply arises from the inferior phrenic artery above, the aorta laterally, and the renal artery inferiorly and is more variable than the venous drainage (Fig. 1). The variable arterial supply rarely causes problems surgically. However, the adrenal venous supply, although more constant, may represent a major surgical problem. The right adrenal vein is short and enters the vena cava on its posterolateral aspect. Visualization of this vein may be obscured at its origin from the vena cava by an enlarged gland. When this vein is not securely ligated, it may result in considerable blood loss, which may be difficult to control intraoperatively. On the left side, the adrenal vein is prominent and exits from the anteroinferior aspect of the adrenal gland and drains into the left renal vein. Congenital anomalies of the adrenal gland,
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such as absence of or accessory adrenal tissue and heterotopia, have been reported. Heterotopic adrenal tissue may be intrahepatic, and, on occasion, the adrenal gland has been found beneath the renal capsule.
The adrenal cortex is microscopically divided into three anatomically and functionally important zones: the zona glomerulosa, the zona fasciculata, and the zona reticularis. The zona glomerulosa produces aldosterone, the zona fasciculata is the site of cortisol production, and the zona reticularis is responsible for elaboration of the sex hormones. The adrenal medulla, which produces catecholamines, is centrally located.
SYNOPSIS OF ADRENAL PHYSIOLOGY
The adrenal cortex produces steroid hormones, which can be catego- rized as corticoids, androgens, aldosterone, estrogens, and progesterone.
The activity of the adrenal cortex is regulated by hormonal mechanisms, in contrast to the adrenal medulla, which is stimulated by the sympathetic nervous system. The structure, growth, and secretory activity of the adrenal cortex is controlled primarily by ACTH from the anterior pituitary gland, except for aldosterone, which is produced by the zona glomerulosa and is regulated by angiotensin. The corticotropin-releasing factor (CRF) from the hypothalamus modulates release of ACTH from the pituitary gland. Of the various hormones produced by the adrenal cortex, only cortisol (hydrocor- tisone) has an important inhibitory feedback effect. The higher the cortisol level is, the lower the ACTH level is, and vice versa. This homeostatic mechanism maintains the level of circulating plasma cortisol within narrow limits unless a stressful situation induces an increase in secretion of ACTH regardless of the level of circulating cortisol.
All adrenal steroids are derived from cholesterol (Fig. 2). The gluco- corticoids are distinguished by the 11-deoxycortisol and 17-a-hydroxypro- gesterone groups, ultimately resulting in production of cortisol. Under basal conditions, the normal adult produces 15 to 20 mg of cortisol a day. Mineralocorticoids include aldosterone, which is produced at a rate of 75 to 125 µg per day. Weak androgens, the 17-ketosteroids, constitute the remainder of the hormones produced by the adrenal cortex and are secreted in quantities of 25 to 30 mg per day. The adrenal androgens (testosterone), estrogens, and aldosterone are not involved in the feedback mechanism that exists between the pituitary gland and the adrenal gland. The effects of corticoid excess are well known to all physicians and lead to the classic stigma of Cushing’s syndrome. In addition, hyperplastic adrenocortical lesions can produce excess testosterone or estrogen with their associated effects.
The renin-angiotensin-aldosterone relationship is an important one. Production of aldosterone is increased by an elevated circulating angiotensin level and, to a much lesser extent, by ACTH. The mineralocorticoid function of aldosterone controls retention of sodium as well as excretion of potassium and hydrogen by the kidney. A deficiency of mineralocorticoid secretion can lead to water loss, hyponatremia, hyperkalemic acidosis, and a contracted blood volume. Excess aldosterone causes the opposite effects, with volume-dependent hypertension and severe hypokalemic alkalosis secondary to potassium wasting. Thus, primary hyperaldosteronism, such as is seen with an adrenal aldosteronoma, will cause sodium retention, increased blood volume, and renin suppression. Conversely, in secondary
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hyperaldosteronism, such as is seen in renal artery stenosis, an elevation in renin results in chronic stimulation and overproduction of aldosterone.
The adrenal medulla functions as a separate unit in the adrenal gland, as would be expected from its distinct embryologic origin. The production of epinephrine and norepinephrine is under the control of the sympathetic nerves, which innervate the medulla. The physiology of catecholamine secretion and action is complex. Norepinephrine is synthesized by the tyrosine-dopa-dopamine pathway and is secreted at postganglionic sympa- thetic nerve fibers, including the adrenal medulla. In the adrenal gland, chromaffin cells convert norepinephrine to epinephrine as a result of the action of catechol-O-methyltransferase. This event can occur only in the adrenal medulla. This information is sometimes clinically helpful in deter- mining whether a pheochromocytoma is located in an adrenal gland or in an ectopic location.
Hypovolemia, upright posture, and cold can activate release of nor- epinephrine from the adrenal gland, whereas hypoglycemia stimulates production of epinephrine. Depending on certain cellular receptor sites, catecholamines have a direct effect on target organs. Beta-adrenergic receptors respond to epinephrines better than to norepinephrines and are responsible for arterial dilatation, venous constriction, bronchodilatation, and increased cardiac rate and contractility. Alpha-adrenergic receptors are primarily responsive to norepinephrine and result in arterial constriction, increased contraction of the gastrointestinal musculature, diaphoresis, and secretion of insulin. Again, norepinephrine triggers alpha-adrenergic recep- tors primarily, whereas epinephrine triggers both alpha-adrenergic and beta-adrenergic receptor sites.
CUSHING’S SYNDROME
Cushing’s syndrome is not a single disease entity. The clinical picture is secondary to chronic hypersecretion of cortisol by the adrenal cortex. It is best to classify patients with Cushing’s syndrome into two major groups, those with an elevated or normal level of circulating ACTH and those with a low or unmeasurable level of ACTH.14 In the series reported by Orth and Liddle, 75 per cent of patients had an elevated level of ACTH and 25 per cent did not.20 Of those with elevated ACTH, 79 per cent will have a pituitary adenoma, and 21 per cent will have an ectopic source outside of the pituitary. When electron microscopy and immunohistochemistry tech- niques are used, cortitroph adenoma cells can be demonstrated in over 90 per cent of Cushing’s disease tumors. Most of these tumors will show basophilic hematoxylin and eosin staining. In patients with an adrenal cause of Cushing’s syndrome (an adrenal adenoma or carcinoma), the circulating ACTH will be low or not measurable.
In patients with a high level of ACTH, it is usually, but not always, possible to separate the pituitary from the nonpituitary source by the level of ACTH and by the ability to suppress this level with dexamethasone. 14 Most pituitary tumors will have ACTH levels below 200 pg per dl (normal 41 to 68) and will demonstrate suppression of ACTH and cortisol with high-
dose dexamethasone (8 mg per day for 2 days).4 Ectopic sources of ACTH are neoplasms that produce the small, biologically active molecule. The ACTH levels in these instances will usually exceed 200 pg per dl and will be independent of suppression by dexamethasone. The most common of these tumors is oat-cell carcinoma of the lung, followed in frequency by bronchial adenoma, carcinomas of the thymus and pancreas, and carcinoid and neural crest tumors. 16
When the diagnosis of Cushing’s syndrome associated with an elevated level of ACTH is made, it is necessary to investigate the pituitary gland. High-resolution CT scanning is useful in demonstrating tumors greater than 6 mm in diameter.21 Magnetic resonance imaging (MRI), especially when accompanied by Gd-DTPA enhancement, promises to improve the diag- nostic accuracy.6 Should the tumor not be visualized on CT or MRI, selective sampling of ACTH levels in the inferior petrosal sinuses and comparing them to peripheral blood ACTH levels will point to a pituitary source of the ACTH and will indicate the correct site of the microadenoma. 23
The treatment of Cushing’s syndrome depends on the site of the tumor. For those in whom the diagnostic evaluation points to a pituitary adenoma as the source of the hormonal hypersecretion, the treatment is transsphenoidal removal of the tumor. In patients with a microadenoma (smaller than 1 cm), the cure rate for Cushing’s disease approaches 90 per cent.1, 4, 19 Cure can be obtained by the preservation of normal anterior pituitary function in most patients although return of normal ACTH-adrenal function may take 6 to 9 months. The cure for patients with suprasellar or invasive tumors is significantly lower, 48 per cent in Boggan’s series.1 It has been demonstrated that recurrence is related to regrowth of the tumor and not to hyperplasia of corticotroph cells in the pituitary.9 In patients in whom a discrete tumor cannot be found or in whom it is not possible to excise a tumor completely, it is reasonable to perform a total hypophysec- tomy in adults past reproductive age.1, 4 It is far easier to treat a patient by hypophysectomy than to risk leaving residual Cushing’s disease. In patients in whom it is not possible to effect cure by transsphenoidal surgery, radiotherapy should be administered. Ultimate cure rates from 50 to 80 per cent can be achieved. 15
Bilateral adrenalectomy for Cushing’s disease is no longer the treatment of choice because the patient is left panhypopituitary and with an 8 per cent chance of Nelson’s syndrome developing. 18 The tumor associated with Nelson’s syndrome tends to be more aggressive and is less responsive to surgery or radiotherapy.22
ADRENAL ADENOMA AND ADENOCARCINOMA
When an adrenocortical adenoma or carcinoma is the source of exces- sive glucocorticoid production, usually a feedback suppression of ACTH levels is observed. As a result, levels of plasma and urinary steroids are elevated, and ACTH levels are suppressed. Adrenal adenomas are usually unilateral and should be identified before operation. Computed tomography
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of the adrenal glands has become the most important diagnostic aid in localizing even small adrenal tumors (Fig. 3). The treatment of patients with an adrenal adenoma is total unilateral adrenalectomy. Supplementation with mineralocorticoids and glucocorticoids is usually temporary in the postoperative period because the function of the contralateral adrenal gland is usually suppressed by the severely lowered level of ACTH. After initial high-dose coverage with corticosteroids for the stress of the operative procedure, the dose is slowly tapered to a maintenance level, which should continue for several months after operation.
ADRENOCORTICAL CARCINOMA
Adrenocortical carcinoma is a rare tumor that may arise from any part of the adrenal cortex and present with a variety of clinical pictures. A number of adrenal carcinomas, however, produce no important hormonal aberration. Cushing’s syndrome and virilization are commonly associated with this malignant tumor. Hormone aberrations in the male are much less obvious because androgenic steroids are commonly produced with carci- noma. Males can undergo feminization, but this occurs less commonly than does virilization in the female. In addition, virilization may be the only effect of an adrenal tumor and almost invariably represents an adrenal carcinoma with a poor prognosis.
In men, adrenal carcinoma may present as a feminizing complex of signs and symptoms instead of Cushing’s syndrome. Gynecomastia reflects conversion of androgen to estrogen. Invariably, these patients have a malignant tumor and a poor prognosis, with a 5-year survival rate of between 9 and 13 per cent.
In females, virilization (acne, hirsutism, and clitoral hypertrophy) may be a finding in Cushing’s syndrome produced by an adenoma but more commonly is caused by exaggerated production of androgens secondary to an adrenocortical carcinoma. In the woman with a virilizing syndrome, when excretory urography with tomography or CT of the adrenal gland
fails to reveal an adrenal mass, an ovarian tumor must be considered. In patients with normal findings on CT of the adrenal gland, sampling of the ovarian vein and venography are necessary to rule out an ovarian arrhen- oblastoma. Occasionally, adrenal angiography is required in a patient with an adrenal carcinoma, and this study characteristically demonstrates neo- vascularity and inferior renal displacement (Fig. 4). Adrenal carcinomas invade the renal veins and vena cava, as is seen with renal cell carcinoma (Fig. 5).
The treatment of patients with adrenal carcinoma is surgical excision. The mean survival time in patients undergoing operation or operation plus chemotherapy is approximately 48 months. Adrenal carcinoma is radiore- sistant, and, therefore, radiotherapy is of little value in altering the patient’s life expectancy. In patients with metastatic disease, removal of the tumor followed by chemotherapy is now advocated as the treatment of choice. Chemotherapy with o,p’-DDD (Lysodren, Mitotane) and amino-gluteth- imide will block production of cortisol and androgen by the metastatic foci, thus achieving subjective improvement resulting from decreased production of steroids, but this treatment does little to improve longevity. The response rate of Mitotane is approximately 60 per cent, and the drug is helpful in relieving symptoms in patients with metastatic carcinoma of the adrenal gland. In addition, an aggressive surgical approach to isolated metastatic deposits occasionally improves palliation.
The workup for Cushing’s syndrome used to be a complex, time- consuming, expensive endocrine evaluation. The newer techniques of direct
measurement of cortisol and ACTH by immunoassay, when correlated with CT of the abdomen and head, permit a more rapid and direct evaluation of glucocorticoid excess and its probable cause (Fig. 6).
PRIMARY ALDOSTERONISM
Primary aldosteronism is a syndrome secondary to increased production of aldosterone by the zona glomerulosa, as first described by Conn in 1955.5
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Primary aldosteronism is an uncommon lesion occurring in less than 1 per cent of patients with hypertension and is recognized by hypertension and hypokalemic alkalosis. About 70 per cent of patients have a cortical adenoma (Fig. 7) as a cause of the syndrome; the remainder have microadenomas of the adrenal gland (Fig. 8). Micronodular adrenal hyperplasia is more common in children than in adults.
The adenomas are typically small, usually less than 3 cm. They produce increased amounts of circulating aldosterones, which result in hypokalemic alkalosis, decreased sodium excretion and increased potassium excretion in the urine, sodium retention, and an increased blood volume resulting in hypertension. The increased blood volume decreases the release of renin by the kidneys. Thus, primary aldosteronism is manifested by a high plasma aldosterone level, a low plasma renin level, and a low potassium level, resulting in muscle weakness, headache, or signs of hypokalemic nephrop- athy or hypokalemic alkalosis. The elevated aldosterone level, when iden- tified, is not suppressed by 2 L of saline solution infused over a 4-hour period. This confirms the diagnosis of primary hyperaldosteronism as the cause of the patient’s hypertension.
In secondary hyperaldosteronism caused by renal artery stenosis, increased release of renin leads to an increased production of angiotensin, which in turn results in increased serum aldosterone levels. Thus, secondary hyperaldosteronism is characterized by an increased aldosterone level along with an increase in the renin level in contradistinction to primary hyperal- dosteronism, which is characterized by an increase in aldosterone level and a suppression in renin level.
When the diagnosis of primary aldosteronism is biochemically con- firmed, radiographic evaluation with CT or MRI usually localizes the adenoma. These diagnostic modalities have a resolution of approximately 1 cm, so that even small adenomas are usually detected by these methods. Left-sided lesions are two to three times more common than right-sided lesions. Attempts should be made to identify the site of the lesion before operation. If CT or MRI fails to localize the tumor, samples of the adrenal vein and adrenal venography (Fig. 9) almost always point to the tumor-
bearing gland. Adrenal infarction (Fig. 10), however, is a potential risk of adrenal venography.
Occasionally, the surgeon must approach the patient without preop- erative knowledge of the location of the lesion. In such instances, bilateral adrenal exploration may be warranted. The left side is usually explored first; when the adenoma is not found in this gland, the procedure on the right side is accomplished.
High aldosterone levels from both adrenal vein samples and failure of venography to demonstrate an adenoma represent granulosa hyperplasia, a poorly understood entity in which the renin levels are not as suppressed as they are in patients with an adenoma. The hypertension fails to respond to bilateral adrenalectomy, making medical treatment preferable.
A rare familial form of hyperaldosteronism has been described in which the aldosterone levels parallel the ACTH levels. These patients respond to small doses of cortisol. These observations bring into question the primary nature of hyperplasia and discourage operation unless an adenoma is discovered before operation. Medical treatment in the form of spironolac- tone (Aldactone), a specific aldosterone antagonist, is available. In addition, a patient with an adenoma who is made normotensive by spironolactone will, in all likelihood, be cured or improved by surgical removal of the adenoma.
PHEOCHROMOCYTOMA
Tumors arising in cells of neural crest origin in the adrenal medulla or sympathetic ganglia are called pheochromocytomas. Biochemically, this is a functioning tumor of catecholamine-producing cells, which are widely distributed during embryonic development. Because of these characteris- tics, the tumor may be found in various locations in the body.
Pheochromocytoma is often associated with other endocrinopathies and can cause life-threatening hypertension. Of the pheochromocytomas, 95 per cent are located in the abdomen or retroperitoneum. The remainder are found within the mediastinum or the skull. Most (80 per cent) are located in the adrenal gland and the remainder in the sympathetic chain (Fig. 11) or in the organ of Zuckerkandl just below the aortic bifurcation. Ectopic tumors have also been found in the bladder and vagina. Malignant pheochromocytomas cannot be differentiated from benign lesions on a histologic basis; only the natural history of the neoplasm and subsequent development of metastatic lesions determine this diagnosis. In children, 20 to 40 per cent have multiple or bilateral tumors. The clinical presentation of pheochromocytoma is hypertension (episodic versus sustained), with a history of chronic weakness, tiredness, tachycardia, diaphoresis, and head- ache. These patients often have difficulty maintaining their body weight.
The diagnosis of a pheochromocytoma is made on the basis of biochem- ical data. Urinary catecholamines as well as catecholamine metabolites should be measured. Urinary vanillylmandelic acid, normetanephrine, and metanephrine levels are elevated in patients with a pheochromocytoma. The most accurate way of documenting the presence of a pheochromocytoma
is by measuring the serum catecholamine level; 98 per cent of patients with a pheochromocytoma will have an elevated serum or urinary level of catecholamines. Patients who are strongly suspected of having a pheochro- mocytoma but whose catecholamine level is normal may be candidates for a tyramine or glucagon stimulation test.
Other neuroectodermal diseases associated with pheochromocytoma are neurofibromatosis, Sturge-Weber disease, and von Hippel-Lindau disease. Sipple’s syndrome, consisting of medullary thyroid carcinoma and hyperparathyroidism, is also associated with pheochromocytoma.
Pheochromocytomas are best localized by abdominal CT and a scan using metaiodobenzylguanidine (MIBG), which has a high degree of accu- racy (Fig. 12). Computed tomography of the chest and skull may also be
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required to locate an ectopic pheochromocytoma. Tumors of the bladder and vagina are usually discovered at the time of cystoscopy or bimanual pelvic examination.
Angiography, although of value in localizing pheochromocytomas, is now infrequently required. When angiography is required, patients should be given phenoxybenzamine (Dibenzyline) before the study to prevent a hypertensive crisis. Angiography is dangerous in an unprotected patient. Even when the patient has been prepared, it is necessary to have phentol- amine or propranolol (Inderal) ready for administration in the angiography suite. Aortic angiography with digital subtraction stains most pheochromo- cytomas with a neovascular blush (Fig. 13). Subtraction also eliminates confusing bony shadows.
When angiography and CT do not localize an ectopic pheochromocy- toma, localization by obtaining multiple venous samples at sites along the superior and inferior vena cava for catecholamines is often helpful. Pheo- chromocytomas that secrete epinephrine predominantly, with only small amounts of norepinephrine, are almost always adrenal in origin. Exceptions have been reported, however.
ALPHA AND BETA BLOCKADE
Surgical removal of a pheochromocytoma presents a challenging prob- lem. Pharmacologic manipulation is necessary to control hypertension or arrhythmia. The alpha blockers, phentolamine and phenoxybenzamine, are important because the alpha effects of severe hypertension and reduced vascular volume predominate. Propranolol, the beta blocker, is added when tachycardia or arrhythmias are still present despite alpha blockade.
After the medications are administered, severe sustained hypertension is converted to normotension, and episodes of hypertension and frontal
headaches usually disappear. The chronically contracted intravascular tree expands, as manifested by a drop in the hematocrit, and is documented by measuring the serial plasma volume. In adults, phenoxybenzamine, 10 mg every 6 hours, is the usual starting dose, and the dose may be increased to as much as 30 to 40 mg every 6 hours. Three to four days of treatment is required for adequate blockade. If tachycardia or arrhythmias occur, pro- pranolol, 5 to 10 mg every 4 to 6 hours, is added to the regimen.
Some controversy exists as to the degree of pharmacologic blockade desired in the preoperative patient. Some physicians prefer complete preoperative alpha and beta blockade; other physicians prefer no blockade so that intraoperative palpation of the contralateral adrenal gland, celiac ganglia, sympathetic chain, preaortic tissue, and organ of Zuckerkandl and subsequent catecholamine activity is not pharmacologically blunted. Intra- operative palpation is helpful in localizing an ectopic pheochromocytoma. The intraoperative use of nitroprusside, 100 mg in 500 ml of 5 per cent dextrose in water, with its half-life of 20 minutes permits intraoperative palpation for ectopic lesions and at the same time precludes dangerous intraoperative changes in the patient’s blood pressure.
Induction and maintenance of anesthesia during operation are difficult and require special precautions. The anesthesia team must be experienced with the management of patients with pheochromocytoma. A central venous pressure catheter, Swan-Ganz catheter, and arterial line are recommended. The intraoperative exploration must be carried out methodically, especially along the sympathetic chain, and resulting hypertensive crisis must be managed appropriately and calmly. When a pheochromocytoma is removed, a wide margin of adjacent tissue should also be included because 10 per cent of these lesions are potentially malignant.
PREOPERATIVE AND POSTOPERATIVE CORTICOSTEROID THERAPY
Any surgeon who assumes the operative responsibilities of adrenal surgery should have a basic knowledge of the special requirements of corticosteroid replacement for patients about to undergo adrenal surgery. Corticosteroid therapy is usually not necessary for patients about to undergo unilateral adrenalectomy who have a normal contralateral adrenal gland confirmed by CT preoperatively. The same is true of patients undergoing unilateral excision of a pheochromocytoma. However, when CT shows contralateral atrophy or agenesis, supplemental corticosteroids are required before, during, and after unilateral adrenalectomy.
Patients undergoing unilateral adrenalectomy for aldosteronism do not require glucocorticoid or mineralocorticoid supplementation. Intravenously administered sodium is usually sufficient to reverse postoperative dehydra- tion, nausea, and lassitude from salt wasting. If the patient does not improve and if preoperative adrenal venography has been performed, the possibility of a contralateral adrenal infarction should be entertained and glucocorticoid and mineralocorticoid supplementation administered.
Patients with Cushing’s syndrome require glucocorticoid therapy be- fore, during, and after operation. Hydrocortisone (Solu-Cortef), 100 mg, or
methyprednisolone (Solu-Medrol), 25 mg, is given intravenously before and during operation. A parenteral dose is similarly given every 12 hours until the patient is taking an oral diet. Prednisone, 30 mg orally every 12 hours, and Florinef, 0.1 mg daily, are prescribed. The dose of prednisone is usually tapered to about 10 mg every 12 hours at the time of discharge from the hospital, and the dose of Florinef is 0.1 mg every other day.
The dose of corticosteroids is tapered over the next several weeks, and then these agents are discontinued. In some patients with adenoma or carcinoma, it may take up to 6 months to discontinue corticosteroid agents because of contralateral adrenal suppression by an autonomous tumor with attendant ACTH suppression. Premature discontinuance will result in adrenal insufficiency manifested by fatigue, fever, nausea, and low cortisol levels. Patients who have undergone bilateral adrenalectomy for Cushing’s syndrome usually take prednisone, 5.0 to 7.5 mg twice a day, and Florinef, 0.1 mg every other day.
SURGICAL APPROACHES FOR ADRENAL SURGERY
The three major routes to the adrenal gland are the anterior transab- dominal approach, the flank or thoracoabdominal approach, and the poste- rior approach.
Anterior Approach
The anterior approach is preferred in most patients with bilateral hyperplasia when pituitary surgery is not appropriate and in patients with pheochromocytoma or adrenal neoplasm when exploration of the extra- adrenal organs is necessary. In obese patients or whenever bilateral exposure of the adrenal glands is required, a chevron incision is preferred (Fig. 14).
The anterior exposure of the left adrenal gland is shown in Figure 15. After the peritoneal cavity has been entered and explored, the posterior peritoneum lateral to the left colon is incised along the white line of Toldt and carried upward to divide the splenocolic ligament. Care must be taken to protect the delicate capsule of the spleen. The plane between the pancreas and the spleen anteriorly and the kidney and the adrenal gland posteriorly is developed by sharp dissection (Fig. 16). The pancreas and duodenum are mobilized and reflected medially, and the spleen is mobilized cephalad. The anterior surface of the adrenal gland is exposed. The dissection is started laterally and carried up toward the apex of the adrenal gland (Fig. 17). Downward traction of the kidney is maintained; this maneuver will aid in gaining exposure of the adrenal gland. The apex of the adrenal gland is brought into view, and the inferior phrenic vessels are clipped with silver hemostatic clips (Fig. 18). The gland can now be rotated medially, and the posterior surface of the gland is completely mobilized (Fig. 19). Dissection is carried medially, and the arteries and veins supplying the adrenal gland are ligated with small silver clips. The adrenal vein is ligated in continuity with 2-0 silk sutures and divided. The adrenal gland is then removed (Fig. 20). When the left adrenal gland is being removed for pheochromocytoma (Fig. 21), the approach is different in that the initial
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steps should be ligation and division of the left adrenal vein. This will lessen elaboration of catecholamine from the left adrenal gland during operative manipulation.
Anterior Exposure of Right Adrenal Gland
The posterior peritoneum lateral to the right colon is incised vertically, and the incision is carried up around the hepatic flexure. The colon is reflected medially, the liver and gallbladder are retracted upward, and the kidney is gently retracted inferiorly to bring the anterior surface of the right adrenal gland into view (Fig. 22). Several of the small hepatic veins may be noted at this point and should be ligated and divided. After the fatty and areolar tissue is dissected off the anterior surface, the adrenal gland is mobilized laterally and posteriorly, meticulously dividing the small vessels between silver clips and avoiding any direct handling of the adrenal gland itself (Fig. 23). The apex of the gland is mobilized, and the inferior phrenic vessels are divided and ligated. The medial aspect of the adrenal gland is approached. The central vein is ligated with 2-0 silk sutures and divided. The remainder of the medial blood supply is ligated with silver clips (Fig. 24). The adrenal gland is freed from the upper pole of the right kidney and removed.
When the anterior approach is used to remove the adrenal gland and its contained pheochromocytoma, control of the major venous outflow of the adrenal gland is the first maneuver in the operative procedure. After the pheochromocytoma has been removed, the entire retroperitoneum is
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palpated carefully. Any suspicious masses are exposed and samples taken for biopsy. Any area that on palpation produces an elevation in blood pressure should be exposed widely; if a second pheochromocytoma is found, it should also be excised. A wide variety of adjacent structures, including the bladder, ureter, bowel or its mesentery, and the great vessels, may be involved. In general, the principles of cancer surgery should apply in such instances, with specific operative techniques varying according to local anatomic needs. In addition, the anterior approach is usually required in patients undergoing secondary and tertiary operative procedures for recur- rent pheochromocytoma.
Flank or Supracostal Approach
In patients with a unilateral adrenal endocrinopathy, a supracostal 11th or 12th rib approach to the adrenal gland is used, depending on the site of the lesion. A flank approach is usually appropriate for patients with an aldosteronoma, small adrenal adenoma, or small adrenal carcinoma. The advantage of this approach, its familiarity to urologic surgeons, is, however, outweighed by two disadvantages. First, only one adrenal gland can be seen at one time, and a decision for total removal, subtotal adrenalectomy, or no surgical intervention must be made without the knowledge of the condition of the contralateral adrenal gland. Second, the standard subcostal incision may result in low access to a high adrenal gland. Therefore, our preference is the supracostal approach in patients undergoing unilateral adrenalectomy.
The patient is positioned for a flank approach supracostal incision (Fig. 25). The incision is made at the tip of either the 11th or 12th rib and carried posteriorly along the border of the rib. The latissimus dorsi, external oblique, internal oblique, transversus abdominis, and intercostal muscles are divided along the upper border of the rib (Fig. 26). The course of the intercostal nerve is followed to dissect the pleura from the inner aspect of the rib (Fig. 27). The cleavage plane between the diaphragm and the retroperitoneal space is mobilized, and the retroperitoneal space is entered.
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Thoracoabdominal Approach
The thoracoabdominal approach is useful in patients with a large adrenal carcinoma who might also require concomitant splenectomy, distal pancreatectomy, or radical nephrectomy. In addition, this is a reasonable approach for patients with a large pheochromocytoma because it affords exposure and palpation of the entire retroperitoneum and abdominal viscera through a single incision. It is also appropriate for patients having secondary and tertiary procedures, such as for recurrent pheochromocytoma or an adrenal carcinoma, which is large and locally infiltrating. The patient is placed in a semioblique position (45-degree angle) with a rolled sheet placed longitudinally beneath the flank. The incision is begun in the ninth intercostal space near the angle of the rib and carried across the costal margin at the midpoint of the contralateral rectus muscle just above the umbilicus (Fig. 28). As an alternative, this incision can be made either in the bed of the 9th or 10th rib. The incision is carried down through the latissimus dorsi, external oblique, internal oblique, transversus abdominis, and the rectus muscles (Fig. 29). After the latissimus dorsi, external oblique, and rectus muscles have been divided, the intercostal muscles are divided in the direction of the incision. The costal cartilage between the 9th and 10th rib is divided (Fig. 30). The peritoneal and pleural cavities are entered. The diaphragm is divided, taking care to avoid injury to the phrenic nerve.
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The lungs are protected with Mikulicz pads, and a large Finochietto retractor is placed in the incision (Fig. 31).
Bilateral Posterior Approach
This is an older approach for removal of both normal adrenal glands as well as an aldosteronoma. The patient is placed in the prone position on
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the operating table with rolls beneath the hips and rib cages (Fig. 32). Two incisions are made over either the 11th or 12th rib and extended medially to the paraspinal muscles (Fig. 33). If necessary, the kidney bar can be elevated to give further flexion. The incision can be made over the 11th and 12th ribs depending on the level of each adrenal gland. The ribs are excised subperiosteally (Fig. 34). The incision is carried down through the periosteum of the rib (Fig. 35). After the periosteum has been divided, the pleura is mobilized superiorly. The diaphragm and pleura are retracted superiorly, and the paraspinal muscles are retracted medially, exposing the adrenal gland and the upper pole of the kidney (Fig. 36).
The major difficulty with this operative approach is controlling the right adrenal vein where it enters the inferior vena cava. When it is difficult to secure this vessel or if the ligature slips off, life-threatening hemorrhage from the inferior vena cava will ensue. It is essential then to gain control of the inferior vena cava through an anterior approach in an urgent fashion. For this reason, I am reluctant to use the posterior approach for adrenal surgery and prefer the other approaches described.
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Figure 35. Incision extended through periosteum. (By permis- sion of Lahey Clinic.)
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Figure 36. Exposure of adre- nal gland. (By permission of Lahey Clinic.)
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Department of Urology Lahey Clinic Medical Center 41 Mall Road Burlington, Massachusetts 01805