Surgery of the Adrenal Glands

George K. Chow, MD, Michael L. Blute, Sr., MD



















Surgery of the adrenal gland consists of operative procedures to correct endocrine abnormalities or to treat malignant disease. As outlined in Chapter 57, various adrenal disorders can be identified and treated medically. When medical therapy is ineffective or does not exist for a particular adrenal disease, surgery becomes necessary.


Traditional open adrenal surgery has been performed since the late 19th century. Various techniques and anatomic approaches have been described for adrenalectomy, but the essential surgical principles have remained unchanged for a century. The introduction of laparoscopic adrenalectomy has revolutionized adrenal surgery and largely supplanted the open approach. However, we are not yet ready to relegate open adrenal surgery to the history books. There is a diminished but vital role for open adrenal surgery in the management of invasive adrenal carcinoma. Furthermore, all urologic surgeons should be familiar with the open techniques in the event that emergent open surgical conversion is necessary.


The future of adrenal surgery is evolving. New technology, such as robotics and percutaneous ablation, is being developed. These minimally invasive nonsurgical approaches may obviate the skills of the surgeon. Nevertheless, it is important that the urologist be part of the treatment team, either as direct practitioner of the technique or as a direct consultant guiding therapy.



History


The first adrenalectomy was performed by Thornton in 1889 for a large tumor in a 36-year-old woman (Thornton, 1890). At the time, Thornton was unaware of the adrenal origin of the patient’s disease and removed the adrenal en bloc with the kidney. Sargent performed the first planned adrenalectomy in 1914 for a large adrenal adenoma. Charles Mayo (1927) performed the first flank adrenalectomy for pheochromocytoma in 1927. As was often the case in these early forays, Mayo was not aware of the exact nature of the pathologic process with which he was dealing and assumed that he was removing an aberrant retroperitoneal nerve.


Young (1936) described the posterior approach using a “hockey stick” incision to access both adrenal glands simultaneously. The thoracoabdominal incision for management of large retroperitoneal masses was first described by Chute and colleagues (1949). In 1965, Turner-Warwick developed and described a supracostal transdiaphragmatic variation of Young’s posterior approach.


Gagner performed the first laparoscopic adrenalectomy in 1991 (Gagner et al, 1992). He used a transperitoneal approach to gain access to the adrenal gland. Also in 1992, Gaur developed and described the first device for balloon dilation of the retroperitoneum. Retroperitoneal access has been developed for both flank (Gasman et al, 1998) and posterior (Baba et al, 1997) approaches.



Surgical Anatomy


The adrenal glands are situated in the retroperitoneum within the Gerota fascia. The right adrenal gland tends to lie more cephalad than the left adrenal gland. The anatomic borders of the right adrenal gland are the liver anteriorly, the vena cava medially, the right kidney laterally and inferiorly, and the diaphragm along its superior and posterior aspects. The medial aspect of the right adrenal gland will often be retrocaval, and the right adrenal vein will enter the inferior vena cava in a posterolateral position.


The left adrenal gland is bordered by the aorta medially, the stomach and body of the pancreas anteriorly, the kidney inferiorly, the spleen superiorly, and the diaphragm posteriorly. The left adrenal gland is often more elongated than the right adrenal gland and will lie in a more superomedial position to the kidney. This tends to place the gland closer to the left renal hilum, and these structures must be accounted for during dissection. The anatomic relationships of the adrenal glands are summarized in Fig. 58–1.



The arterial blood supply to the adrenal gland can be variable but tends to derive from three major sources on each side. Each adrenal gland receives branches from its ipsilateral inferior phrenic artery (superior adrenal arteries), aorta (middle adrenal arteries), and renal artery (inferior adrenal arteries). The venous drainage is typically simple; a single adrenal vein drains into the vena cava directly on the right and into the left renal vein on the left. Accessory veins (5% to 10%) that drain into the right renal vein, right hepatic vein, or inferior phrenic vein can be present (Fig. 58–2).



Lymphatic drainage from the adrenal glands consists of a lateral aortic lymph node chain extending from the diaphragm to the ipsilateral renal artery.



Clinical Indications and Selection of Patients






Past Surgical History


Is open surgery indicated when there is a history of previous surgery close to the adrenal gland? The laparoscopic approach can be tailored to deal with past surgical history; a patient with previous transabdominal surgery could have a retroperitoneal laparoscopic procedure (Caddedu et al, 1999), and a history of previous open flank surgery could be addressed by performing a transperitoneal laparoscopic procedure. Furthermore, Gill and colleagues (2001) have reported their experience with a transthoracic laparoscopic approach that may be ideally suited for this situation. The thoracic cavity is entered thorascopically, the diaphragm is divided, and the adrenal gland is approached superiorly.



Size


Tumor size is a relative contraindication to laparoscopic surgery. In the initial experience of many laparoscopists, a cutoff of 5 or 6 cm was chosen because of the increased risk of treating an adrenal cortical carcinoma. Subsequently, ample empirical evidence has accumulated to suggest that specimen size is not necessarily a contraindication to laparoscopic adrenalectomy. MacGillivray and colleagues (2002) noted no difference in operative time, blood loss, complication rate, and hospital stay among 12 patients with large tumors (mean, 8.2 cm; range, 6 to 12 cm) and 36 patients with small tumors (mean, 2.5 cm; range, 0.4 to 5.6 cm).


In contrast, Hobart and colleagues (2000) noted increased operative time (205 minutes vs. 158 minutes; P = .07), increased blood loss (400 mL vs. 113 mL; P = .009), higher complication rate (21.4% vs. 8.9%; P = .21), and higher open conversion rate (14.3% vs. 2.2%; P = .14) in comparing 14 large tumors (mean, 8 cm) with 45 small tumors (mean, 2.2 cm). However, Hobart did find that operative time, blood loss, hospital stay, narcotic use, and complication rate were lower with laparoscopic adrenalectomy than with traditional open adrenalectomy for large tumors. Although a higher morbidity could be expected with larger tumors, morbidity was still less than with open surgery.


Conversion to open surgery is most often due to infiltrative adrenal cortical carcinoma. In the largest series, conversion occurred electively after initial laparoscopic exploration and not because of hemorrhage or other emergent causes. MacGillivray and colleagues (1996) concluded that preoperative computed tomographic scanning can identify those infiltrative tumors that are likely to be invasive carcinoma.


MacGillivray and coworkers (2002) and Henry and colleagues (1999) recommend an upper size limit of 12 cm for laparoscopic adrenalectomy. However, keep in mind that computed tomographic scanning can underestimate specimen size by as much as 16% (Lau et al, 1999).



Obesity


With a worldwide epidemic of obesity, it is an increasingly common occurrence to operate on morbidly obese patients. Rather than obesity being a relative contraindication, laparoscopy may offer a less morbid alternative for adrenalectomy on obese patients. Comparing results between obese patients (body mass index greater than 30) who underwent laparoscopic adrenal or renal surgery and those who underwent open surgery, Fazeli-Matin and colleagues (1999) noted that patients who underwent laparoscopic surgery had fewer complications (18% vs. 47%; P = .21), less blood loss (50 mL vs. 300 mL; P = .03), less narcotic use (P = .01), and shorter hospital stay (<24 hours vs. 5.5 days; P = .01). However, these surgeries were performed by a veteran laparoscopist, and obesity may remain a relative contraindication for less experienced surgeons.



Adrenal Cortical Carcinoma


Laparoscopic adrenalectomy on adrenal cortical carcinoma can be a daunting task. Adrenal carcinomas tend to be larger (>6 cm). Henry and colleagues (2002) noted that of 150 consecutive laparoscopic adrenalectomies, none of the smaller (<4 cm) tumors (N = 102) was malignant. In contrast, 12.5% of tumors larger than 4 cm (N = 48) were malignant. Using a 6-cm cutoff, Prager and coworkers (2004) noted that 21.2% of tumors larger than 6 cm were malignant versus 1.9% of lesions smaller than 6 cm. Also, the prospect of invasion by infiltrative lesions into surrounding structures can prohibit successful laparoscopic surgery. However, if computed tomography indicates that no local invasion is present and the lesion is not excessively large, laparoscopic adrenalectomy is possible.


Known adrenal vein or vena caval involvement is an absolute contraindication to laparoscopic surgery. However, in one case report, Kim and colleagues (2004) described an intraoperatively discovered adrenal vein thrombus with a 7-cm adrenal mass. With use of atraumatic vascular clamps, the renal vein was entered, and the intact tumor thrombus was removed en bloc with the adrenalectomy specimen.


Cancer control is dependent on adherence to the same oncologic principles as in open surgery. Wide local excision with periadrenal fat is necessary for good local control to be obtained. Adrenal cortical carcinoma tends to be an aggressive disease, and locoregional recurrence can develop as often as 60% (Vassilopoulou-Sellin and Schultz, 2001). Most reports of postoperative adrenal cortical carcinoma recurrence have been in case reports. Henry and colleagues (2002) published a summary of 12 cases of carcinoma recurrence in the medical literature. In 25% of the cases, the authors admitted to specimen disruption during the case.



Preoperative Management


It is important to correct any electrolyte abnormalities that may result from an endocrinologically active adrenal tumor. Most notably, aldosteronoma can result in hypokalemia that may require potassium repletion and administration of a potassium-sparing diuretic. Hypertension should also be treated before surgery.


With a pheochromocytoma, α-adrenergic blockade should be started 2 weeks before surgery. Phenoxybenzamine is most often used for adrenergic blockade prior to surgery. Some patients with tachycardia may benefit from concurrent β blockade. Alternatively, an α1-selective blocker such as prazosin or doxazosin can be used. Intraoperatively, high blood pressure can be treated with nitroprusside or a short-acting β blocker like esmolol. Volume repletion is important to prevent the postoperative hypotension secondary to loss of tonic vasoconstriction after removal of a pheochromocytoma.


Patients with Cushing syndrome require correction of electrolyte abnormalities and hyperglycemia before surgery. These patients may benefit from administration of adrenolytic agents such as mitotane or aminoglutethimide.


Potential errors in preoperative preparation are summarized in Table 58–3.


Table 58–3 Errors in Preparation of Patients for Adrenal Surgery























Primary Aldosteronism


Cushing Syndrome




Incidentalomas

Adrenal Carcinoma


Pheochromocytoma




Modified from Vaughn ED. Complications of adrenal surgery. In: Taneja SS, Smith RB, Ehrlich RM, editors. Complications of urologic surgery: prevention and management. 3rd ed. Philadelphia: WB Saunders; 2001. p. 363.


A mechanical bowel preparation can be helpful for open or laparoscopic transperitoneal surgery. Retroperitoneal surgery may not require this bowel preparation. All patients should receive appropriate preoperative antibiotics. A nasogastric or orogastric tube can be placed to decompress the bowel, especially helpful for transperitoneal cases. The placement of a urinary catheter to help measure urine output and to decompress the bladder is essential.



Open Adrenalectomy


Open adrenalectomy can be performed through either a transperitoneal or retroperitoneal approach. The transperitoneal approaches include midline, subcostal, and thoracoabdominal. The retroperitoneal approaches include flank and posterior lumbodorsal. The advantages of the transperitoneal approaches are better exposure for larger tumors and excellent access to the great vessels and retroperitoneum. The main disadvantages are prolonged ileus and difficult exposure in morbidly obese patients. The retroperitoneal approach results in less ileus and may result in shorter hospital stays. There is a smaller operative field, and access to larger tumors and surrounding involved organs may be difficult. The best surgical approach for a given adrenal disease is indicated in Table 58–2.



Flank Retroperitoneal Approach




Right Side


The patient is placed in flank position with the right side facing up (Fig. 58–3). The bed is placed in maximal flexion, and the kidney rest is deployed to accentuate the space between the costal margin and iliac crest. Palpation is used to identify the course of the 11th rib. The skin and fat overlying the 11th rib are incised, and the fascia and muscle overlying the rib are divided. (Fig. 58–4).




Once the anterior surface of the rib is exposed, the anterior periosteum is cauterized, and the periosteal elevator is used to scrape it off the anterior rib surface. The edges of the periosteum on the superior and inferior aspects of the rib should now be visible. The periosteal elevator is used to develop a plane between the posterior rib surface and the posterior leaf of the periosteum. The Doyen instrument and surgical cautery are used to strip the periosteum off the rib from the tip of the rib back toward the paraspinal muscles. With the rib cutter, the 11th rib is excised (Fig. 58–5). A rongeur can be used to remove any sharp remnants on the rib stump. Cautery or bone wax can be used to render the marrow hemostatic.



Next, the neurovascular bundle is identified and freed with sharp and blunt dissection to avoid injury during subsequent dissection and closure (Fig. 58–6). The lumbodorsal fascia is entered sharply with Metzenbaum scissors, and blunt dissection is used to dissect the peritoneum off the transverse fascia anteriorly. The flank muscles and their accompanying fasciae are divided anteriorly—the external oblique, internal oblique, and transverse abdominal. Next, the posterior muscle diaphragmatic attachments are divided with cautery. The pleura is sharply and bluntly dissected off the superior edge of the 12th rib.



The plane between the Gerota fascia and the peritoneum can be started with the cautery or sharp dissection. Once it is identified, this plane can be maximally developed with blunt dissection. The peritoneum needs to be freed from the superior aspect of the Gerota fascia as well. Once the peritoneum is mobilized, on the right side, the vena cava can be visualized, and with cephalad dissection, the adrenal gland and renal vein can be seen as well. Placement of a self-retaining retractor is essential for maximal exposure to be obtained.


Dissection of the adrenal gland typically begins along the medial border of the gland with the vena cava. The overlying peritoneum is divided, and blunt dissection is used to expose the plane between the medial surface of the adrenal gland and the lateral surface of the vena cava. The adrenal vein is often difficult to identify until this plane is developed. The adrenal vein is dissected out with a right-angled instrument such as a Mixter forceps. Surgical ties or clips can be placed to ligate the adrenal vein. In our opinion, surgical ties are more reliable than standard titanium clips. However, locking surgical clips may be substituted for added security. There are numerous arterial branches to the gland that can be ligated and divided individually. Alternatively, many authors attest to the utility of the harmonic scalpel in hemostatically dividing arterial attachments. Once this is done, the psoas muscle is often visible posteriorly. Superior attachments are divided with the aid of surgical cautery or harmonic scalpel. Downward traction on the kidney assists with this dissection. Inferomedial attachments to the kidney are taken with sharp or cautery hook dissection.


Dissection of the left adrenal gland is similar except that the aorta is visualized, and the adrenal vein originates from the renal vein. Other authors have described supracostal technique with intentional violation of the pleura. This approach may be helpful for larger tumors.


Closure of the incision consists of a two-layer closure with a running No. 1 polydioxanone suture. The deep layer consists of the transverse abdominal muscle, internal oblique muscle, and fascia. The outer layer consists of the external oblique muscle and fascia. Skin closure can be completed with surgical staples or absorbable subcuticular suture.



Lumbodorsal Posterior Approach


The main advantage of this approach is the ability to easily access both adrenal glands for bilateral surgery. The disadvantages include a limited operative field and respiratory limitation. If bleeding is extensive, it can be difficult to control from this position. The posterior approach requires prone positioning of the patient with arms extended cephalad. The procedure has been extensively modified over time—with or without rib resection, transthoracic through the diaphragm, or diaphragm sparing. A rib-resecting, diaphragm-sparing approach is described.




Right Side


An incision is made along the course of the right 11th rib (Fig. 58–7). This is taken down to the periosteum, and the rib resection is performed in a manner similar to that described for flank incision. The diaphragm is dissected off the underlying peritoneum and liver. The peritoneum is then dissected off the Gerota fascia, which is retracted inferiorly. If a bilateral procedure is undertaken, a Finochietto retractor can be used to assist in bilateral exposure (Fig. 58–8

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Jun 4, 2016 | Posted by in ABDOMINAL MEDICINE | Comments Off on Surgery of the Adrenal Glands

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