Simple renal cysts (Bosniak I and II)

Most simple cysts are totally asymptomatic and will never demand active treatment.

Although surgical treatment of Bosniak I and IIF renal cysts is not normally needed, patients may present with important symptoms such as pain, infection, and urinary obstruction. In fact, simple cysts can in some cases grow enough to result in compression or rupture of collecting systems, likely related to a trauma [12]. Moreover, cystic fluid can become infected, needing surgical treatment. As a simple cyst grows, it may rarely result in systemic hypertension or impairment of renal function by causing tubular obstruction or local ischemia [13].

Nowadays, percutaneous drainage and sclerotherapy are the most frequent first‐line treatments for symptomatic simple renal cysts [14]. Laparoscopic treatment is accomplished for patients in whom conservative procedures have failed or are contraindicated (obese patients, bleeding disorders, complex location of the cyst, etc.). Another indication for first‐line laparoscopic treatment is the presence of concomitant pathologies of the ipsilateral kidney or upper urinary tract which necessitate surgical treatment (i.e. pielolithotomy, pyeloplasty, simple tumor enucleation, or partial nephrectomy) [15].

Marsupialization, decortication, and unroofing are the three main techniques described for simple renal cyst laparoscopic treatment. The patient should be preoperatively informed that if malignancy is suspected intraoperatively, the treatment can vary toward a more radical surgical excision [16].

Complex renal cysts (Bosniak III and IV)

Diagnosis of simple cysts is often incidental in the absence of specific symptoms. A specific meta‐analysis found that Bosniak class II, III, and IV cysts are associated with the risk of 24, 41, and 90% of malignancy, respectively [17].

Some authors have described the possibility of cyst aspiration to rule out the presence of malignant cells, even if this practice is strongly not recommended because of the high risk of tumor seeding and the possibility of a false‐negative result [18]. Conservative management is never recommended for lesions Bosniak III–IV because of the high suspicion of cancer and, as for percutaneous aspiration, preoperative biopsy is not indicated.

Finally, in view of the findings that approximately 40–60% of class III and 85–100% of class IV cysts prove to be malignant, laparoscopic simple enucleation, partial or radical nephrectomy is always demanded [1, 2].

The main limit for the laparoscopic approach is represented by intraparenchymal cysts, treatment of which can be difficult because of the risk of significant bleeding and injury to the collecting system. In these situations, an open surgical approach should be considered.

Preoperative evaluation and patient preparation

Even if standard abdominal ultrasound study is used to diagnose simple renal cysts, a detailed preoperative radiological evaluation is required to plan the surgical strategy and to avoid potential complications. Three‐phase renal CT with precontrast, nephrogram, and delayed images is the gold standard among imaging modalities. It gives crucial information about the number, size, location, exophytic/endophytic growth of the renal cyst, and its relation to renal hilum, the pyelocalyceal system, and proximal ureter. Moreover, it allows the relation with contiguous structures such as bowel, liver, or spleen and Bosniak classification to be identified. Finally, this study can guide surgeons on the decision as to what surgical approach to use. In general, a transperitoneal approach is indicated for cysts located in the anterior renal face or parapelvic or when concomitant diseases have to be treated, such as stones affecting the ipsilateral kidney [15]. The retroperitoneal approach is more appropriate for posteriorly located or inferior pole cysts.

In patients where CT is contraindicated (i.e. chronic kidney disease or previous contrast medium reactions), abdominal MRI is a valid alternative. Previous surgical history, body mass index (BMI), and patient comorbidities should be ruled out in order to choose the most suitable therapeutic approach.

Patient preparation includes a complete evaluation of previous abdominal surgical procedures or diseases in order to exclude situations which may impair laparoscopic treatment (i.e. previous transperitoneal procedures, open surgery procedures, hepatosplenomegaly, chronic obstructive pulmonary disease, kyphoscoliosis, or coagulation disorders) [20].

An adequate preoperative bowel preparation regime is required for the transperitoneal approach, but is not useful for the retroperitoneal one. Trichotomy of the surgical access point is necessary and the surgical site should be marked before access to the operating room. A detailed informed consent including surgical procedure and potential complications should be obtained from the patient. Prophylactic antibiotic is given at the time of general anesthesia induction and a Foley urethral catheter is placed before patient positioning. An orogastric tube is only required for transperitoneal procedures.

Operating room configuration and patient positioning

Once general anesthesia has been administered, patient positioning maneuvers can begin, according to the type of approach being used. The operating room configuration is independent of the type of approach selected. All members of the operating room team can visualize the procedure from a principal monitor placed on the opposite side from the surgeon. The primary tower with insufflator, light source, and camera box has to be visualized by the surgeons in order to be able to modify the setting during the procedure. For transperitoneal approach, the surgeon and assistant are on the contralateral side of the renal cyst, facing the patient’s abdomen (Figure 105.1); for retroperitoneal approach, the surgeons stay behind the patient’s back (Figure 105.2).

The table is slightly split in order to have tension on the interested flank. This position is also achieved by using light Trendelenburg placement and by putting a raising towel under the contralateral flank. For the transperitoneal procedure the patient is placed in a modified flank position with a 45° of patient angulations to the operating table. For the retroperitoneal approach, the patient is placed in a full flank position. Moreover, the working space is increased by splitting the operating table at the lumbar level in order to achieve a wide space between the iliac crest and the 12th rib.

All pressure points (including contralateral elbow, legs, and ankles) are properly padded to avoid decubitus lesions. An axillary roll is preferred to protect the contralateral brachial plexus. The lower leg is flexed and the upper one is kept extended and some pillows are positioned between them in order to avoid direct pressure contact. The umbilicus is at the level of the operating table break. The patient is secured to the operating table with wide tape at the level of axilla, hips, and legs. The surgical field is prepared and painted with povidone–iodine (Betadine®) from the nipples to pubis level and from the contralateral pararectal space up to the level of the spine.

Laparoscopic access can be achieved using different techniques, depending on surgeon personal experience and patient characteristics [21].

Trocar positioning – transperitoneal procedure

For laparoscopic transperitoneal access we prefer to adopt a linear port configuration, rather than the triangulation rule as classically depicted. As described by Harper et al., three 5 mm trocars are positioned on the ipsilateral pararectal line [22]. The camera trocar, cranial, with a 30° lens, is positioned two fingerbreadths below the costal margin on the site where the Veress needle was previously placed in order to achieve a 15 mmHg pneumoperitoneum. The other ports are then positioned with a distance of four fingerbreadths between them under direct vision. This trocar positioning avoids interference between surgeon and camera assistant and improves the ergonomics (Figure 105.3) [15]. In the case of obese patients, all ports can be positioned more laterally, according to patient habitus. A low transverse incision such as Pfannenstiel is performed if needed for extraction of surgical specimen.

Trocar positioning – retroperitoneal procedure

As the retroperitoneal approach gives a smaller working field and a limited area for port positioning, particular maneuvers are needed in order to achieve ideal access. The patient is placed in a fully flank position without any angulation, in order to displace the posterior peritoneum as far as possible. The first 5 mm trocar is placed under direct vision along the posterior axillary line halfway between the iliac crest and the tip of the 12th rib, in the area called Petit’s triangle. By mechanical blunt dissection, the retroperitoneal working space is progressively developed at the same time as CO₂ insufflation. Some authors suggest the use of a mechanical balloon dilator, progressively insufflated with 800–1000 ml [23].

The peritoneum is then medialized and two additional 5 mm trocars are positioned along the middle and anterior axillary line at the level of the first trocar site under direct vision. A 5 mm port is used for the optic and the others are the working ports for the surgeon, allowing a good balance between vision and ergonomics [24, 25] (Figure 105.4).