35 Posterior Retroperitoneoscopic Adrenalectomy Martin K. Walz

35.2.1 Preparation . . . 333 35.2.2 Positioning . . . 333

35.2.3 Placement of Trocars . . . 334

35.2.4 Preparation of the Adrenal Gland . . . 334 35.2.5 Partial Adrenalectomy . . . 335

35.2.6 Final Steps . . . 335

35.3. Indications and Contraindications . . . 336 35.4. Tips and Tricks . . . 336

35.4.1 Retroperitoneal Space . . . 336 35.4.2 Misplacement of Trocars . . . 336 35.4.3 Hemorrhage . . . 337

35.4.4 Retroperitoneal Fatty Tissue . . . 338 35.5 Results . . . 338

35.5.1 Perioperative Results . . . 338 35.5.2 Postoperative Results . . . 338 35.6 Summary . . . 339

References . . . 339

35.1 Introduction

The posterior retroperitoneoscopic approach to the adrenal glands is based on the combination of the clas- sical open posterior route and the technique of mini- mally invasive surgery. By doing so the advantages of both methods are integrated: the direct approach and limited access minimizing operative trauma. In 1993 and 1994 the technique of posterior retroperitoneo- scopic adrenalectomy was independently developed at different locations. Early descriptions were published from Turkey, United States of America, Italy, and Ger- many [5, 7, 8, 13]. Further studies demonstrated oper- ative feasibility [15] and – compared with the laparo- scopic approach – shorter operative times and less blood loss [1].Currently,the posterior retroperitoneo- scopic access has become one of the standard ap- proaches for adrenalectomy.In this chapter we present

35.2 Surgical Technique

35.2.1 Preparation

Posterior retroperitoneoscopic adrenalectomy is per- formed under general anesthesia with laryngeal intu- bation and assisted ventilation. In addition, a naso- gastric tube is placed routinely. In patients with a pheochromocytoma, previous cardiac diseases or se- vere arterial hypertension, a central venous catheter and an arterial line are inserted. Swan-Ganz catheters and urinary catheters are not used routinely. Patients with pheochromocytomas are pretreated with high- dosage phenoxybenzamine up to a final level of 2–3 mg/kg body weight [19]; patients with hyperal- dosteronism receive spironolactone 3–4 weeks prior to operation. Intraoperatively, intravenous antibiotics (i.e. 2 g cefazolin) are given.

35.2.2 Positioning

The procedure is performed with the patient in the

prone,half-jackknife position (Fig.1).Ideal placement

is essential to create sufficient space between the ribs

and the iliac crest: the hip joints and the knees are bent

(75–90°) and fixed in this position. The patient is po-

sitioned without lordosis on mattresses allowing in-

clination (“sagging”) of the abdomen. The lateral ab-

dominal wall is placed in a vertical line with the table

allowing free movement of all instruments.

to place a fourth trocar below the first line of ports in order to pull the kidney down by a separate retractor.

Mobilization of the adrenal gland begins medially and caudally between the diaphragm and the adrenal gland.In this area,on the right,the gland arteries cross the vena cava posteriorly. These vessels are separated by electrocoagulation or clip application. Clips are useful,especially in well-vascularized pheochromocy- tomas. By lifting up the adrenal gland the caval vein is demonstrated posteriorly in its retroperitoneal-cra- nial segment (Fig. 4). The vena cava is clearly visual- ized by the clearing of any fibro-fatty tissue. During this phase the renal vein and artery must not be iden- tified. Sometimes, an upper pole artery of the kidney crosses the caval vein. The short suprarenal vein be- comes clearly visible running posterolaterally usually close to the diaphragm. This key vessel is meticulous- ly prepared for a length of 1 cm and dissected between Fig. 1. Positioning of the patient in posterior retroperitoneo-

scopic adrenalectomy. Hip joints and knees are bended

Fig. 2a, b. Positioning of the trocars for posterior retroperi- toneoscopic adrenalectomy. (a Modified from [16]) 35.2.3 Placement of Trocars

Initially, a 1.5 cm transverse incision just below the tip of the 12th rib is made. The retroperitoneal space is reached by blunt and sharp dissection of the abdomi- nal wall. A small cavity is prepared with a finger for digitally guided insertion of two 5 mm trocars about 5 cm lateral and medial to the initial incision site with particular attention to the subcostal nerve. Thus, safe trocar placement is possible without visual control.

The medial 5 mm trocar is inserted at an angle of about 45°, allowing a direct view of the adrenal region and avoiding bending of the camera. The lateral 5 mm trocar is placed exactly lateral and below the 11th rib. A blunt trocar with an inflatable balloon and an adjustable sleeve is introduced into the initial incision site and sealed by balloon inflation. The capnoretro- peritoneum is created by maintaining a CO

pressure of 20–25 mmHg. Retroperitoneoscopy is performed with a 5 mm 30 degree endoscope that is initially in- troduced via the middle trocar and later positioned via the medial trocar near the spine (Fig. 2a, b). The initial view shows the fascia of Gerota,which must be opened by dissection (Fig. 3a, b).

35.2.4 Preparation of the Adrenal Gland

After creation of the retroperitoneal space underneath

the diaphragm by displacing the fatty tissue inferior-

ly, the upper pole of the kidney is seen. By doing so the

area of the adrenal gland is visualized. The kidney is

retracted downwards by one of the instruments from

the middle or lateral trocar. Sometimes it is necessary

clips (Fig. 5a, b). Mobilization of the right adrenal gland is completed by lateral and cranial dissection where further small vessels can be found.

For a left-sided retroperitoneoscopic adrenalecto- my, the adrenal gland vein must be prepared in the space between the adrenal gland and the diaphrag- matic branch medial to the upper pole of the kidney (Fig. 6). After dissection of the main vein (Fig. 7a, b), preparation of the adrenal gland is continued medial- ly, laterally, and cranially. All manipulations of the ad- renal gland are performed carefully using blunt pal- pation probes to prevent injury to gland tissue. For the whole dissection the monopolar electrocautery probe is used allowing a precise preparation of all essential Fig. 3. a Initial view on Gerota’s fascia. b After dissection the perirenal and periadrenal fatty tissue becomes visible

Fig. 4. Right-sided posterior retroperitoneoscopic adrena- lectomy. View after creation of the retroperitoneal space (vc, vena cava; a, adrenal gland with tumor; k, upper pole of the right kidney; arrow, adrenal vein). (Modified from [16])

structures. The harmonic scalpel is also practical but creates relatively dense fog in the small retroperitoneal working space (300–400 ml).

35.2.5 Partial Adrenalectomy

If a partial adrenalectomy is planned, the margin of the neoplasia has to be precisely identified. Therefore, it may be necessary to resect a portion of the sur- rounding fatty tissue. Additionally, retroperitoneo- scopic ultrasonography utilizing a 10 mm flexible 10 MHz probe is utilized.After clear identification, the tumor is resected with a margin of 0.5–1.0 cm of nor- mal tissue. These resections are regularly performed by electrocoagulation with or without clip application [17]. Preservation of the adrenal vessels depends on the individual situation and is not related to cortical function [4, 19].

35.2.6 Final Steps

Extraction of the adrenal tissue is performed through

the middle incision with a retrieval bag system (e.g.,

Endocatch,Tyco Norwalk,CT,USA).Depending on the

tumor size the incision site occasionally has to be en-

larged. Skin and fascia closure are performed after the

optional retroperitoneal drain insertion with reab-

sorbable materials. On the day of the operation bed

rest is abandoned and complete oral intake is allowed.

35.3 Indications and Contraindications (Table 1)

The posterior retroperitoneoscopic approach to the adrenal glands is indicated in adrenal tumors up to 6–7 cm in diameter, and in those patients with adrenal hyperplasia. Tumors less than 4 cm in size, and pa- tients with little retroperitoneal fatty tissue, are ideal candidates for this procedure.

Due to the limited working space and the increased risk of malignancy, tumors larger than 6–7 cm should not be operated via the posterior retroperitoneoscop- ic access.This also applies to tumors infiltrating neigh- boring organs or structures especially in patients with

adrenal metastases. Another contraindication is a short distance (less than 3–4 cm) between the ribs and the iliac crest in the prone position,i.e.in patients with severe osteoporosis or after spine fractures. In these patients placement of trocars is impossible. In ex- tremely obese patients (body mass index 45) the ab- domen causes severe compression of the retroperi- toneum. In such situations even a gas pressure of 30 mmHg does not create a sufficient and safe retro- peritoneal space.

35.4 Tips and Tricks

35.4.1 Retroperitoneal Space

A basic aspect of posterior retroperitoneoscopic adrenalectomy is the increased gas pressure with lev- els between 20 and 25 mmHg. This allows the creation of a sufficient space in the retroperitoneum without any relevant hemodynamic changes [6] even in obese patients. Additionally, an initial balloon dissection – as described in the early publications [14] – can be avoided.

35.4.2 Misplacement of Trocars

In rare instances of misplacement of one of the trocars causing tears of the pleura, the procedure can be con- Fig. 6. Left-sided posterior retroperitoneoscopic adrenalec- tomy. View after creation of the retroperitoneal space (rv, re- nal vessels; a,adrenal gland; k,left kidney; arrow,adrenal vein joining the diaphragmatic vein). (Modified from [16])

Fig. 5a, b. Right-sided retroperitoneoscopic adrenalectomy

(vc, vena cava; av, adrenal vein; ag, adrenal gland)

35.4.3 Hemorrhage

The major potential complication is bleeding. By the posterior retroperitoneoscopic approach the risk of arterial bleeding is minimal, as the main renal arter- ies and the aorta are usually not seen. Clips can con- trol lesions of small arteries, i.e. of the adrenal gland or the upper pole of the kidney.Venous bleeding may occur from suprarenal veins or from the caval vein, but due to the high CO

pressure relevant blood loss does not occur. We have seen very few significant hemorrhages from these vessels and a complete con- trol could always be achieved by clip application or temporary compression.Variations in the anatomy of the suprarenal veins are a special problem. They are not found on the left side, but on the right side we en- countered such anomalies in about 10% of patients [18]. Especially, conjunctions of adrenal veins with posterior hepatic veins may complicate dissection.

Another advantage of the posterior retroperitoneo- scopic adrenalectomy is the small space in which the Fig. 7a, b. Left-sided posterior retroperitoneoscopic adrenal-

ectomy (k, upper pole of left kidney; av, clipped adrenal vein;

ag, adrenal gland)

Table 1. Indications and contraindications of posterior retroperitoneoscopic adrenalectomy Indications Primary functioning tumors (size ≤6–7 cm) i.e. Pheochromocytoma

Conn’s adenoma Cushing’s adenoma Primary non-functioning tumors (size ≥3 cm and ≤6–7 cm)

Metastases (≤4 cm and without infiltration of surrounding structures except fatty tissue)

Nodular or non-nodular hyperplasia with hypercortisolism

Contra- Primary adrenal functioning or non-functioning tumors Laparotomy or laparoscopic approach indications (size >6–7 cm)

Malignant tumors (except small metastases) Laparotomy

Extreme obesity Lateral laparoscopic approach possible

No distance between ribs and iliac crest Lateral laparoscopic approach possible

whole procedure is performed, limiting the potential maximum blood loss.

35.4.4 Retroperitoneal Fatty Tissue

In patients with large amounts of fatty tissue in the retroperitoneum all surgical procedures for adrena- lectomy become extremely difficult. In these patients, typically with Cushing’s syndrome or Cushing’s dis- ease, the benefit of an endoscopically performed pro- cedure is high especially by avoiding large abdominal incisions. The trick in endoscopic adrenalectomy is to resect the fatty tissue around the upper pole of the kid- ney and the adrenal gland.Sometimes,this can be per- formed simply by suctioning of the typically soft and friable fatty tissue. Thereby, the essential anatomic structures and landmarks can be identified within a few minutes.

35.5 Results

35.5.1 Perioperative Results

Studies of posterior retroperitoneoscopic adrenalec- tomy demonstrate both the feasibility and the safety of this approach (Table 2). The conversion rate to open surgery is about 5% and decreases with growing expe- rience [15,18].Operative time ranges between 100 and 200 min; blood loss is minimal. Due to the direct ac- cess,we can achieve operative times of less than 30 min

in ideal patients with minimal retroperitoneal fatty tis- sue and small tumors. Up to now, no perioperative death has occurred after posterior retroperitoneo- scopic adrenalectomy. This approach has also been used in recurrent adrenal tumors especially after transperitoneal open operations and in retroperi- toneal paragangliomas [19, 20].

Hemodynamic studies show a significant increase of cardiac output, stroke volume, mean arterial pres- sure, and mean pulmonary arterial pressure following retroperitoneal insufflation in the prone position.

Heart rate, systemic vascular resistance, and pul- monary vascular resistance do not change, however, making it a safe procedure in patients with cardiac risk factors [6]. Intraoperatively, absorption of CO

by the retroperitoneal tissue without relevant alterations of arterial blood gas analysis has been demonstrated [11]. Further studies show stable pulmonary function in patients undergoing this approach both pre- and postoperatively [9].

35.5.2 Postoperative Results

Long-term results following posterior retroperitoneo- scopic adrenalectomy confirm biochemical cure in functioning adrenal tumors even after partial adrena- lectomy [12, 17, 18]. Local or locoregional recurrences have not been published. We have noted temporary weakness of the subcostal nerve in about 11% of pa- tients leading to relaxation or hypoesthesia of the abdominal wall [18].

Table 2. Studies of posterior retroperitoneoscopic adrenalectomy with more than ten procedures (n.d., no data) Author Year Adrenalecto- Conversions Operative Blood loss Remarks

mies (n) (n) time (min) (ml)

Mercan [8] 1995 11 0 150 n.d.

Duh [5] 1996 14 0 202 n.d. Comparison with

transperitoneal approach

Walz [14] 1996 30 5 124 40 Five partial adrenalectomies

Baba [1] 1997 13 1 142 32 Comparison with

transperitoneal and retro- peritoneal-lateral approach

Sasagawa [9] 1998 15 0 162 12 Only partial adrenalectomies

Baba [2] 1999 26 1 144 44 Six procedures: “solo surgery”

Balogh [3] 2000 14 2 128 100

Walz [18] 2001 142 7 101 54 39 partial adrenalectomies

Sasagawa [12] 2003 47 1 198 41 Only partial adrenalectomies

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