Surgical Applications

Because of their fairly central position in the abdominal cavity, the adrenal glands cannot be felt, and few tumors grow large enough to be palpated. Approaches to the gland can be made through the posterior, lateral, and anterior surfaces. Laparoscopic adrenalectomy has become in recent years the technique of choice for most adrenal tumors. Surgical techniques are described in greater detail in other chapters of this book. The anatomic landmarks are mentioned here as an introduction.

Open Adrenalectomy

POSTERIOR APPROACH

The posterior approach, originally described by Young,48 offers the technical advantage of being extraperitoneal, extrapleural, and subdiaphragmatic and the clinical advantage of being associated with a low postoperative morbidity. The incision is usually over the 11th rib. Structural stratification of the posterior thoracic wall in this region49 is summarized in Table 64-2.

During right adrenalectomy, the dissection plane encounters the costopleural sinus, which can be reflected superiorly; rarely, it might be necessary to incise the pleura and diaphragm. After incision of Gerota's fascia, dissection between the right kidney and the vena cava allows identification of the adrenal gland. Posteriorly and laterally, dissection can proceed quickly because few major vessels cross this space. When dissecting on the medial aspect, it must be remembered that there is usually only one adrenal vein and that this is often only 1 cm wide and only 2 to 3 mm long. The vein is sometimes found at the upper pole of the adrenal gland, and its point of entrance into the cava lies immediately beneath the liver. Once the adrenal vein has been divided, the tumor usually becomes much more mobile, and remaining connections can be divided safely.

Left adrenalectomy has fewer pitfalls. It is important to recognize and protect the spleen and to differentiate the inferior surface of the pancreas, which may look similar to an

TABLE 64-2. Anatomic Stratification in the Plane of Incision Lines for Adrenalectomy

Layer Landmark Description

Posterior Approach

1 Skin

2 Superficial fascia

3 Serratus posterior inferior muscle

4 External intercostal muscle

5 Internal intercostal muscle* The intercostal nerves and vessels run between the internal intercostal and transversus muscies, under the inferior border of the corresponding rib, with vein, artery, nerve (VAN) from superior to inferior

6 Transversus thoracis muscle

7 Endothoracic fascia and parietal pleura or peritoneum

8 Pararenal fat

9 Gerota's fascia

10 Perirenal fat and adrenal capsule

Anterior Approach

1 Skin The natural lines of cleavage in the skin (Langer's lines)

run almost horizontally around, and the incision, therefore, intercepts them

2 Superficial fascia Camper's fascia is the superficial fatty layer

Scarpa's fascia is the membranous layer

3 Deep fascia Thin areolar tissue covering the muscles

4 Muscles Three broad thin sheets (external oblique, internal oblique, and transversalis) that are aponeurotic in front and form a fibrous sheath (rectus sheath) for the wide vertical rectus abdominis muscle Right and left rectus sheaths fuse on the midline and form the linea alba, which extends from the xiphoid process down to the symphysis pubis The anterior wall of the rectus sheath is firmly attached to it by the muscle's tendinous intersections, whereas the posterior wall is not attached The structure of the rectus sheath varies Between the costal margin and the level of the anterior superior iliac spine (ASIS), the aponeurosis of the internal oblique splits and one part passes in front of the rectus muscle (together with the external oblique) and one part passes behind the rectus muscle and lies in contact with the fascia transversalis Below the level of ASIS, the aponeurosis of all three muscles from the anterior wall of the rectus sheath and the rectus muscle lies in contact with the fascia transversalis

5 Fascia transversalis Continuous with a similar layer lining the diaphragm and the iliac muscle (forming together one continuous lining for the abdominal lining of the abdominal and pelvic cavities)

6 Extraperitoneal fat

7 Parietal peritoneum

Continued

TABLE 6<1-2. Anatomic Stratification in the Plane of Incision Lines for Adrenalectomy—Cont'd

Vascular and Nervous Supply of the Anterior Abdominal Wall over the Incision Line

Cutaneous nerves'

Pass in the interval between the internal oblique and

transversus muscles

Derived from the anterior rami of the lower six

thoracic (the lower five intercostal nerves and the

subcostal nerve) and the first lumber (iliohypogastric

and ilioinguinal nerves) spinal nerves

Innervate the skin of the anterior wall, the muscles,

and the peritoneum

Arterial supply

Branches of the superior and inferior epigastric

arteries (for the area near the midline) and from the

intercostal, lumbar, and deep circumflex iliac artery

(for the flanks)

Superior epigastric artery (one of the terminal

branches of the internal thoracic artery) enters the

upper part of the rectus sheath, descends behind the

rectus muscle, and anastomoses with the inferior

epigastric artery (a branch of the external iliac artery);

these vessels must be identified and safely ligated

when transecting the muscles

Venous drainage

Network of veins that radiates from the umbilicus and

then into the axillary vein (via the lateral thoracic

vein) and into the femoral vein (via the superficial

epigastric and long saphenous veins); a few small

vems (the periumbilical veins) drain along the

ligamentum teres into the portal vein (one of the

important portosystemic anastomoses)

Cutaneous lymph vessels

Above the umbilicus: upward into the anterior

axillary lymph node

Below the umbilicus: downward into the superficial

inguinal nodes

'From the angle of the rib, the muscle is replaced by its aponeurosis, the posterior (internal) intercostal membrane

'Innervation oi the dermatomes corresponding to the incision line (T7 is situated in the epigastrium, just over the xiphoid process; T10 includes the umbilicus) makes high spinal anesthesia (epidural) necessary tor postoperative pain control.

V « intercostal veins draining into tlie azygos vein (on the right) or the inferior hemiazygos vein (on the left), A = intercostal arteries (branches of the thoracic aortal; N = intercostal nerves (anterior rami of the thoracic spinal nerves),

edge of the adrenal gland. Definitive pedicles may not be identified so clearly, but important tethering feeding vessels that fix the gland medially inferiorly and superiorly must be divided. The left adrenal vein may be identified as a discrete vessel entering the renal vein, and its length and width allow control and safe ligature division.

ANTERIOR APPROACH

The anterior approach was initially advocated by Cahill, one of the pioneers of adrenal surgery,50 because of the advantage of simultaneous bilateral exploration, but it is more difficult, more time consuming, and associated with a greater morbidity (especially in the obese patient with Cushing's syndrome). It is advantageous especially when the adrenal disease is bilateral, when the tumor is large (>10 cm), or when there are preoperative indications that the tumor has invaded surrounding anatomic structures. Because of the progress in preoperative diagnosis and localization, the use of the anterior approach is decreasing.

A long, curved transverse incision ("reversed smile") is used, with the center point situated halfway between the umbilicus and the xiphisternum. A vertical (midline or paramedian) incision has also been advocated. The anatomic stratification in the incision line is outlined in Table 64-2.

Left Adrenalectomy. There are three ways of accessing the adrenal region.51

1. Incision of the posterior parietal peritoneum lateral to the left colon, continued upward, dividing the splenorenal ligament (important relations are with the spleen, the splenic vessels, and the pancreas, which are enveloped by the splenorenal ligament, and caution should be used to avoid injury)

2. Opening of the lesser sac through the gastrocolic omentum (incision should be longitudinal, outside of the gastroepiploic arcade)

3. Through the left mesocolon, with the problem of maintaining the main branches of the middle and left colic arteries forming the vascular arcade and yet allowing enough space.

Anterior access to the adrenal gland allows easy recognition of the hilum and isolation of the adrenal vein from the elements of the renal pedicle.

Right Adrenalectomy. After mobilization of the hepatic flexure of the colon, the liver is carefully retracted upward; to provide maximum exposure of the adrenal gland, the falciform and the right triangular ligaments are carefully divided. The duodenum is mobilized in its second portion (Kocher's maneuver) by incision on its lateral aspect (the avascular peritoneal reflection), allowing exposure of the vena cava, the right adrenal gland, and the upper pole of the right kidney. In this area, there are important relations to remember with the common bile duct and the gastroduodenal artery. The critical step is the clamping of the right adrenal vein because it is short, leaves the gland on its anterior aspect, and enters the vena cava on its posterior surface.

Early control and ligation of the adrenal vein in surgery for pheochromocytomas have been advocated in an attempt to control the amount of catecholamines released in circulation during tumor handling. Whichever technique of adrenalectomy is chosen, however, it is clear to any operator that this ideal is not easily achieved, and in some approaches the adrenal vein might be the last connection to be divided, allowing severance of the tumor from the patient.

Laparoscopic Adrenalectomy

Laparoscopic surgery of the adrenal glands is described in detail in Chapter 74.

The largest experience has been with nonfunctioning adrenal masses (incidentalomas) and with aldosteronomas. The laparoscopic dissection of Cushing's adenoma has been described as moderately difficult due to the relatively higher retroperitoneal fat content present in these patients. Bilateral adrenalectomies for Cushing's disease have been described in patients who failed transsphenoidal pituitary ablation. Laparoscopic removal of pheochromocytoma has proved to be a safe alternative in skilled hands. The role of laparoscopic adrenalectomy for isolated adrenal metastases is still controversial.

Contraindications to laparoscopic adrenalectomy include adrenal carcinoma and adrenal masses greater than 10 cm.

TRANSABDOMINAL LAPAROSCOPIC ADRENALECTOMY

Left Adrenalectomy. The splenic flexure is mobilized medially to expose the lienorenal ligament. The ligament is then incised to demonstrate the short gastric vessels posteriorly behind the stomach. This allows the spleen to fall medially, exposing the retroperitoneal space. The adrenal gland, the adrenal mass, and the adrenal vein are identified. Grasping the perinephric fat, the lateral and anterior parts of the adrenal gland are dissected avoiding to grasp the adrenal gland or tumor directly, because the tissue may tear.

For smaller adrenals (<5 cm), the gland is dissected infe-romedially. This allows for early identification and clipping of the adrenal vein. As dissection is continued upward, adrenal branches of the inferior phrenic vessels are clipped. For larger glands, dissection proceeds superiorly, clipping the adrenal branches of the inferior phrenic vessels.

Right Adrenalectomy. A retractor is placed through the most anterior port and the right hepatic lobe is retracted anteriorly. The lateral right hepatic attachments are divided along with the right triangular ligament. The adrenal and its mass are identified. The inferolateral edge of the right adrenal gland is identified and dissected inferiorly.

For glands less than 5 cm, the right adrenal vein is visualized early and taken. The adrenal branches of the inferior phrenic vein are clipped and divided as the dissection is completed upward. For adrenals greater than 5 cm, the lateral and superior dissections are completed first; dissection is then carried caudally to identify the adrenal vein, which is clipped and divided.

RETROPERITONEAL LAPAROSCOPIC ADRENALECTOMIES

One approach used by some surgeons is to create a space around the adrenal gland with an air-filled balloon inserted retroperitoneally. This allows for minimal trauma to organs within the peritoneal cavity. The patient is placed in prone jackknife position and a balloon trocar is placed in the retroperitoneal space, insufflated, and then removed. Operative and retracting ports are placed.

Left Adrenalectomy. Laparoscopic ports to insert a camera and instruments (usually three or four ports) are positioned below the left rib cage. The left adrenal gland is exposed after the spleen is freed up from attachments over the adrenal, the colon is moved down, and the tissue over the upper pole of the kidney opened to reveal the adrenal gland. The inferomedial border of the gland is identified and dissected, exposing the left renal vein. The vein is divided along with remaining vascular twigs.

Right Adrenalectomy. Laparoscopic ports (four or five) are inserted along the right rib cage for camera, instruments, and a liver retractor. Mobilizing the right lobe of the liver from the tissues of the back of the abdomen is critical. Once the retroperitoneum is exposed and the liver retracted, the vena cava is exposed and, by following it, the adrenal vein is identified. Depending on the anatomy of the region and the reason for the adrenalectomy procedure, the adrenal vein or veins may be divided early. Alternatively, arterial branches into the gland may be divided at this point before the vein is clipped, stapled, or oversewn.

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment