Technical Modifications for the Management of Complex Renal Cysts

The laparoscopic approach to ablating simple renal cysts is relatively straightforward; however for complex renal cystic lesions, there are technical modifications worthy of mention.

Peripelvic Renal Cysts

Although for peripelvic cysts both transperitoneal and retroperitoneal laparoscopic techniques are feasible, the transperitoneal approach provides optimum exposure of the renal hilum, a larger working space, and is therefore the approach of choice. Excision of Gerota's fascia and perirenal fat overlying the anteromedial aspect of the kidney is necessary to provide optimal visualization of the renal hilar structures.

Due to the close proximity of peripelvic cysts to the renal vasculature and collecting system, meticulous dissection must be carried out to avoid injury to these structures.

The branches of the renal vasculature and collecting system are often distorted and splayed by the peripelvic cysts, making them difficult to identify and differentiate from the cyst itself. Prior attempts at percutaneous drainage can also result in inflammation and scarring, making the tissue planes between the peripelvic cyst and hilar structures even less distinct. Placement of a ureteral catheter with retrograde injection of indigo carmine-or methylene blue-stained saline is useful in identifying the course of the splayed collecting system and for identification of collecting system injuries. Precise identification of renal vascular braches can be aided by the use of laparoscopic ultrasound with Doppler if available. Unlike with simple peripheral renal cysts, excision of the entire anterior cyst wall may not be feasible with peripelvic cysts. Overzealous attempts at cyst wall excision as well as cauterization of the cyst lining can lead to vascular and/or collecting system injury.

Only partial cyst wall excision is advisable with spot cauterization of the cyst edge. Suture fixation of a tag of perirenal fat, omentum, or polytetrafluoroethylene (Gore-Tex®) wick into the residual cyst cavity can encourage drainage and prevent reaccumulation of cyst fluid (9).

Autosomal Dominant Polycystic Kidney Disease

In patients with autosomal dominant polycystic kidney disease, kidney size is often large and can at times occupy the majority of the abdominal cavity, displacing adjacent organs.

A mechanical bowel preparation is recommended prior to cyst ablation in patients with autosomal dominant polycystic kidney disease to help decompress the bowels and optimize the already limited working space secondary to the large kidneys.

The transperitoneal approach provides the most exposure to the numerous cysts encountered in patients with autosomal dominant polycystic kidney disease and allows for access to cysts located both anteriorly and posteriorly; however success with retroperitoneal access has also been reported (21). Dissection of Gerota's fascia and perirenal fat off the entire renal surface and complete mobilization of the kidney are required to expose and gain access to as many cysts as possible.

The use of a laparoscopic ultrasound probe has proven very effective in facilitating the identification and treatment of deep-seated renal cysts, with one report citing a total of 635 cysts ablated in a single session.

All autosomal dominant polycystic kidney disease patients should undergo preoperative placement of a ureteral catheter with retrograde injection of dyed saline during and at the conclusion of cyst ablation to help identify any inadvertent entry into the collecting system.

Laparoscopic exploration offers a minimally invasive method of evaluating and treating renal cystic lesions. Patients must be aware of the possibility of requiring a partial or radical nephrectomy if malignancy is detected.

Large-to-medium cysts are punctured and drained, the exposed cyst wall excised, and the edge of the cyst cauterized. Through the defects of these unroofed cysts, deeper cysts that are identified are similarly unroofed and drained. The lining of the cyst cavities are not routinely cauterized or packed, but rather marsupialized with the peritoneal cavity.

■ Small-to-tiny cysts can be merely incised, punctured, or cauterized.

Transcutaneous ultrasound has been described to aid in intraoperative localization of deep-seated renal cysts in patients with autosomal dominant polycystic kidney disease. However, the pneumoperitoneum can interfere with the accuracy of cyst localization and therefore must first be decompressed (22).

The use of a laparoscopic ultrasound probe has proven very effective in facilitating the identification and treatment of deep-seated renal cysts, with one report citing a total of 635 cysts ablated in a single session (23).

In addition, intraoperative reference to preoperatively obtained imaging studies may be helpful in identifying and ablating as many renal cysts as possible. Due to the large number of cysts located both peripherally and in proximity to the renal hilum, the risk of injury to the collecting system is increased.

All autosomal dominant polycystic kidney disease patients should undergo preoperative placement of a ureteral catheter with retrograde injection of dyed saline during and, at the conclusion of cyst ablation, to help identify any inadvertent entry into the collecting system.

Indeterminate Renal Cysts

With the use of contrast-enhanced cross-sectional imaging techniques, the vast majority of renal cystic lesions can be categorized radiographically as benign versus neoplastic. However, a small subset of lesions still remain indeterminate, making management difficult (24). As compared to the surgical management of most renal cysts, the management of indeterminate (i.e., Bosniak class II and III) lesions is more controversial with reports citing a 14% to 41% risk of malignancy (25,26).

Laparoscopic exploration offers a minimally invasive method of evaluating and treating these lesions. Patients must be aware of the possibility of requiring a partial or radical nephrectomy if malignancy is detected.

Fluid is aspirated from these indeterminate renal cysts during laparoscopic exploration and sent for cytologic analysis. Biopsies of suspicious regions (e.g., areas of discoloration, nodularity, or calcifications) along the base of the renal cyst are sent for frozen section histopathologic analysis. Partial or radical nephrectomy can be performed immediately if malignancy is detected on frozen section. A staged operative procedure may be required following receipt of final histopathologic analysis in cases where frozen section assessment is inconclusive. In the absence of malignancy, the cyst is managed similar to that of a simple cyst.

In the case of collecting system injury and repair, the ureteral stent is left in place for two to four weeks depending on the extent of injury and removed cys-toscopically in the office.

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