The operative technique was according to the references (
1, 2, 6, 7). 2.1. Anesthesia and Patient Preparation
The procedure is performed under general anesthesia. A nasogastric tube is placed routinely. A urinary catheter is not routinely inserted for two reasons: the relatively short operative time, and the reduction in urine output following retroperitoneal insufflation. This may give the anesthesiologist a false sense of insecurity. Patients with pheochromocytoma require an arterial line and a central venous catheter. Antibiotic prophylaxis is done in the form of a single dose of Cefazolin (2 - 3 gm based on the patient’s weight) intravenously. Venous thromboembolic disease (VTED) prophylaxis typically in the form of intermittent pneumatic compression is routinely used because the patient’s position during the procedure involves compressing the iliac and femoral veins. Furthermore, the IVC is also compressed by the elevated retroperitoneal pressure. Nevertheless, VTED following PRA has not been reported.
2.2. Patient’s Position
The patient is placed prone in a half-jackknife position, with the hip joints and knees bent at 75 - 90° and fixed in this position (
Figure 1). The purpose of this position is to create an adequate working space between rib 12 and the iliac crest. The back should be flat (no lordosis). This allows sagging of the abdomen which in turn allows the abdomen to adequately accommodate viscera when the retroperitoneal pressure rises, maintaining the working space created in the retroperitoneum. This is done by placing two towel rolls one beneath the lower thorax and another across the iliac crests. Alternatively, a surgical cushion/stomach support could be used for this purpose ( Figure 2).
Figure 1. Patient’s Position in Posterior Retroperitonoscopic Adrenalectomy
The operating table here supports proper positioning of the hip joints and knees.
Figure 2. Stomach cushion; Its Use is Very Helpful in Allowing Sagging of the Abdomen During Posterior Retroperitonoscopic Adrenalectomy.
Unlike other surgical procedures, the patient should not be centered on the operating table. Instead, the patient’s lateral abdominal wall on the side destined for surgery, should be placed in line with the edge of the operating table to allow the free movement of instruments during the procedure. However, if both sides are to be operated upon simultaneously (concordant bilateral retroperitonoscopic adrenalectomy; COBRA), the patient should be placed in the center of the table.
2.2.1. Trouble Shooting
Occasionally, the available operating table does not support proper positioning of the patient (i.e. hip joints being bent at 75 - 90°). This could be easily resolved by removing part of the operating table (leg support) and replacing it with a chair.
In most cases, a 5 mm 30° camera provides a satisfactory view. Dissection is carried out using Bipolar Scissors (LigaSure® 5 mm blunt tip 37 cm). Bipolar scissors are preferred over ultrasonic shears because the amount of surgical smoke generated by the latter, obscures the surgeon’s vision in the available limited working space.
2.4. Port Placement
Classically, a 1.5 cm incision was made just below the tip of rib 12 and the retroperitoneal space is then entered sharply using scissors, and a 10 mm port was placed. However, as the position and orientation of rib 12 related to the operative field varies among individuals due to variations in body habitus, a more appropriate way of placing the first port is midway between the spine and lateral abdominal wall just below and parallel to rib 12. Placement of the second port (5 mm) is digitally guided and does not require visual control; the tip of rib 11 is palpated with the index finger and the port is placed just lateral and below the tip of rib 11 in line with the first port. The third port (5 mm) is placed only after creation of the working space and visualization of the kidney to avoid inadvertent entry into the thorax.
2.4.1. Creation of the Working Space
With the scope in port 1 and a grasper in port 2, CO
2 insufflation is started at 20 mmHg and can be raised to 30 mmHg if required, as in obese patients. The space below the diaphragm is created by displacing fatty tissue downward until the upper pole of the kidney is visualized ( Figure 3).
Figure 3. Preparation of the A, Working Space; B, Entry Into Gerota’s Fascia Displacing the Fatty Tissue Downward Until the Upper Pole of the Kidney is Visualized.
2.4.2. Placement of the Third Port (5 mm)
This is done under direct vision. The port is inserted lateral to the paraspinous muscles, parallel to the spine and is directed cranially, at an almost flat angle to the skin. There are two reasons for this special technique of port placement. First, it should always be remembered that the adrenal glands are found in close proximity to the spine, and that the third port (medial port) will ultimately serve as the camera port. Accordingly, such port placement allows direct visualization of the gland. Second, this technique minimizes the risk of subcostal nerve injury whether during port insertion or during the procedure as the port tends to be fixed at the gland and not freely mobile. With the use of this technique for port placement, the reported incidence rate of subcostal nerve injury is only around 10% and is transient. This is significantly favorable compared to its conventional posterior counterpart. Eventually, all three ports are situated along a straight line just below Rib 12 (
Figure 4. Final Port Position; All Ports are Aligned Just Below and Parallel to Rib 12.
2.4.3. Alternative Technique for First and Second Port Placement
After making a 1.5 cm incision midway between the spine and lateral abdominal wall, a 10 mm port cannula (without trocar) is pushed directly into the retroperitoneal space. It should be remembered that the distance to the retroperitoneal space is about 1.5 cm and that entry into the space is accompanied by the sensation of “loss of resistance”. Entry into the retroperitoneum should be controlled by applying opposing forces on the cannula. Extra care is required in Cushing’s patients due to tissue friability in this subgroup of patients. The second port is placed under vision after creation of the working space.
Both sides can be operated on simultaneously by two surgical teams (COBRA). In such cases, an equal pressure should be maintained on both sides at all times even if the intervention is over on one side. Pressure differences allow the compression or decompression of one side or the other one.
2.5. Dissection and Resection
At the commencement of dissection, the medial port should serve as the camera port, and the middle and lateral ports are for the surgeons’ working hands. The kidney should be retracted downwards by an instrument in either the middle or lateral port. Sometime, placement of an additional port, below the line of existing ports, may be required for retracting the kidney. The adrenal gland is mobilized medially (3 O’clock to 9 O’clock direction) and caudally (along the plane between the lower border of the adrenal gland and the superior border of the kidney). On the right side, the adrenal arteries are seen crossing the posterior surface of the IVC. Dividing the adrenal arteries, frees the confluence of the adrenal vein and the IVC. The gland is then lifted off the IVC exposing the adrenal vein that enters the posterior aspect of the IVC (
Figure 5. On the Right Side, the Upper Part of the Adrenal Gland Lies Partially Behind the IVC and the Adrenal Vein Exits Below the Apex
Therefore, once the gland is lifted off the IVC, the adrenal vein can be seen entering its posterior aspect (the tip of the energy device). This requires dividing the adrenal arteries that are found inferomedially crossing the posterior surface of the IVC.
On the left side, dissection starts in a similar manner. The vein is prepared in the area between the adrenal gland and the left hemidiaphragm medial to the upper pole of the kidney; the area where the adrenal arteries are found (
Figure 6). The middle adrenal artery typically covers the confluence of the adrenal and inferior phrenic veins ( 8). The vein is then divided and dissection is completed while lifting the gland from the venous stump. Care must be taken to identify and preserve a superior polar artery (to the kidney) that is present in 20% - 30% of individuals. On the left side, extended mobilization of the upper pole of the kidney is essential as the lower pole of the adrenal gland lies in front of the kidney.
In PRA, division of the adrenal veins is done towards the end of the procedure. This contradicts the vein-first dogma. Controlling the vein first especially in cases of pheochromocytoma, was considered as the golden rule to prevent catecholamine surges related to gland manipulation. However, it has been demonstrated that delayed division of the vein is as safe as dividing it first (
9- 11). Delayed division of the adrenal vein does not significantly increase hemodynamic changes during endoscopic adrenalectomy via the lateral transperitoneal or the posterior retroperitonoscopic approach. Thus, the vein-first dogma is no longer valid.
Figure 6. On the Left Side, the Adrenal Vein (the Tip of the Energy Device) is Exposed in the area Between the Adrenal Gland and the Left Hemidiaphragm Medial to the Upper Pole of the Kidney
The left adrenal vein is typically joined by the inferior phrenic vein before draining into the left renal vein. The inferior phrenic nerve could be safely preserved.
At this point, it is worth emphasizing that in PRA, the aim is to dissect the superior pole of the kidney and thus, the adrenal gland is dissected en bloc with its surrounding fatty tissue. It is not itself targeted nor is it necessary to clearly visualize it. It should also be re-emphasized that dissection is carried out medially and caudally. The cranial aspect of the gland is dissected towards the end of the procedure so that it would serve as a natural means of retraction during the procedure (
Figure 7. Left Side; Dissecting the Cranial Attachment of a Adrenal Gland Towards the End of the Procedure
The superior pole of the kidney is seen below the energy device, and the caudal aspect of the adrenal gland and its surrounding fat have been completely dissected free from it.
2.5.1. Potential Hazard Related to the Anatomy of the Adrenal Veins
Detailed knowledge of surgical anatomy is the key to a successful surgery. In PRA, this becomes clearly evident when considering anatomy of the adrenal veins particularly the one on the right. The anatomy of the left adrenal vein is usually constant and is typically joined by the inferior phrenic vein before draining into the left renal vein. The inferior phrenic vein could be preserved in most instances. On the other hand, anatomic variants of the right adrenal vein exist in about 13% of cases and have been found to be related to certain patient- and tumor- related features (
12). Anatomic variations include: the absence of a main adrenal vein, the presence of additional small veins, and a double adrenal vein ( 12). The right adrenal vein sharing confluence with an inferior accessory right hepatic vein has also been reported ( 7, 13). In the experience of the developer of PRA (Dr Walz), the greatest potential hazard is related to misidentification of the right adrenal vein; mistaking it with a posterior hepatic vein ( 14). In situations where the adrenal vein is not identified with certainty, a useful tip is to complete the dissection of the gland without dividing the vein. In other words, the gland is left hanging only from its vein ( Figure 8). A complete understanding of the anatomic variations in the drainage of the right adrenal vein is paramount for the safe performance of endoscopic adrenalectomy.
Figure 8. The Right Adrenal Gland Suspended Only From Its Vein; This is a Useful Technique in Situations Where an Adrenal Vein is Confused With a Posterior Hepatic Vein
The background demonstrates the blue tinge of the peritoneum overlying the liver.
2.6. Concluding the Operation
The field is routinely irrigated and hemostasis is secured at a low pressure to prevent any tamponade effect of high retroperitoneal pressure (
Figure 9). Drain placement is not routinely required. It could be placed following partial adrenalectomy when a potential risk of remnant bleeding exists. The specimen is retrieved in an endobag via the middle port that might need to be enlarged ( Figure 10). Occasionally, specimens need to be morcellated for successful retrieval. The patient is allowed oral intake upon full recovery from anesthesia, and ambulation encouraged. Occasionally after long interventions, the patient’s skin may become erythematous all the way up to the face. This is not worrisome. It is only transient and resolves completely within a few hours after desufflation. Patients’ informed consent was obtained regarding the use of photos related to their surgeries for scientific purposes.
Figure 9. Final View of the Operative Field Following Resection of the Left Adrenal Gland
The background represents the peritoneum overlying the stomach and spleen. Drains are not routinely required.
Figure 10. The Adrenal Gland Resected en Bloc With Its Surrounding Fatty Tissue.