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Figure 2 ■ Transverse ultrasound images obtained through the acoustic window provided by the liver allow the simultaneous localization of the Visiport® device and the kidney. Source: From Ref. 16.

Figure 2 ■ Transverse ultrasound images obtained through the acoustic window provided by the liver allow the simultaneous localization of the Visiport® device and the kidney. Source: From Ref. 16.

After the kidney has been positively identified, Gerota's fascia is incised with laparoscopic scissors and the perinephric fat dissected away to reveal the inferior pole of the kidney.

After positive identification of the surface of the kidney, laparoscopic biopsy forceps are used to obtain one to five cortical biopsies from the surface of the kidney, taking care to avoid deep samples containing medullary tissue.

Bleeding from the biopsy sites is controlled under direct vision using a 5-mm argon beam coagulator and by packing the sites with oxidized cellulose.

the tip of the Visiport device during advancement through the abdominal wall and the outline of the kidney thus ensuring that the trocar was being placed correctly (Fig. 2).

In patients without morbid obesity, an alternative technique can be applied wherein the retroperitoneum is first insufflated using a Veress needle prior to the placement of the first trocar. Capelouto et al. (17) first placed a Veress needle in the posterior axillary line 1 cm above the iliac crest at a 5° to 10° angle, and insufflated the retroperitoneum after confirming correct placement of the needle. Following insufflation, the Veress needle was removed, and a 1 cm incision was made in that location and the laparoscope was introduced into the retroperitoneum followed by balloon dissection of the retroperitoneum. Current modifications of this access technique have abandoned the balloon dilation, and the Visiport device is used to introduce the laparoscope following insufflation. Additional working space in the retroperitoneum is created by blunt dissection with the laparoscope.

Once in the retroperitoneum and insufflation established, the laparoscope is used to bluntly dissect tissue in the retroperitoneum revealing Gerota's fascia overlying the kidney. After sufficient space has been created, a 5-mm port is placed under direct vision in the anterior axillary line between the level of the first port and the level of the iliac crest (Fig. 1) and secured to the skin with suture. In general, the 5-mm trocar is the working port. However, if a 5-mm laparoscope is also available, the 10-mm trocar can also serve as a working port.

After the kidney has been positively identified, Gerota's fascia is incised with laparoscopic scissors and the perinephric fat dissected away to reveal the inferior pole of the kidney.

Proper identification of the kidney can sometimes be challenging, particularly if there is a large amount of perinephric fat. In these cases, intraoperative laparoscopic ultrasound using a 10-mm probe can be used to help identify the kidney prior to harvesting the biopsies (8). If intraoperative ultrasound is used, a 5-mm laparoscope is placed medially in the working port and the ultrasound probe is placed in the 10-mm trocar.

After positive identification of the surface of the kidney, laparoscopic biopsy forceps (Fig. 3) are used to obtain one to five cortical biopsies from the surface of the kidney taking care to avoid deep samples containing medullary tissue.

Frozen sections of the tissue are sent for pathological analysis to confirm renal origin of the biopsy sample and to determine adequacy of harvested tissue.

Bleeding from the biopsy sites is controlled under direct vision using a 5-mm argon beam coagulator and by packing the sites with oxidized cellulose.

When the argon beam coagulator is used, it is important to vent the retroperi-toneum to avoid overinsufflation. While awaiting the results of the frozen sections, insufflation pressure should be decreased to 5 mmHg and the biopsy site observed for adequate hemostasis for 5 to 10 minutes. After acquiring confirmation that adequate renal samples were obtained and complete hemostasis achieved, the carbon dioxide gas is evacuated from the retroperitoneum and the ports removed. Fascia does not need to be closed in this location, thus only the skin is closed using an absorbable suture. The patient is then awakened and brought to the recovery room. Patients are observed overnight with the vast majority of patients discharged the following day.

Figure S ■ Laparoscopic cup biopsy forceps.

Laparoscopic ultrasound to positively identify the kidney can avoid the complication of inadvertent biopsy of nonrenal tissue. It is also important to take superficial biopsies of the cortex. Deeper bites may result in the acquisition of mainly medullary tissue, increased bleeding, increased risk of arteriovenous fistula formation, or inadvertent violation of the collecting system, which increases the risk of urinary leak and fistula formation.

While this procedure is safe and is associated with relatively few complications, several points should be kept in mind to minimize the risk of complications. As noted above, gaining access to the retroperitoneum can be challenging, particularly in obese patients. The use of intraoperative ultrasound to identify landmarks to facilitate the safe placement of trocars is invaluable. Using this technique, Chen et al. (15) reported successful biopsy in eight patients with a mean body mass index of 52.8 in a mean operative time of 118 minutes and with an estimated blood loss of 71 mL.

The use of laparoscopic ultrasound to positively identify the kidney in equivocal cases can avoid the complication of inadvertent biopsy of nonrenal tissue. It is also important to take superficial biopsies of the cortex. Deeper bites may result in the acquisition of mainly medullary tissue, increased bleeding, increased risk of arteriovenous fistula formation, or inadvertent violation of the collecting system, which increases the risk of urinary leak and fistula formation.

After obtaining hemostasis, it is prudent to decrease the insufflation pressure from 20 to 5 mmHg before removing the trocars to ensure that complete hemostasis has been achieved, because high insufflation pressures can mask bleeding.

Laparoscopic renal biopsy is generally well tolerated. The majority of patients return home within 24 hours, with most of the remaining patients being discharged within 48 hours.

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