Indications and contraindications for robotic pyeloplasty

The indications for robotic-assisted laparoscopic pyeloplasty are the same for any pyeloplasty, regardless of approach. Indications for pyeloplasty in adults can be categorized as either clinical or radiological. PUJ obstruction is a radiological diagnosis, made with a contrast enhanced CT scan showing hydronephrosis and a classic tapering at the PUJ and functional nucleotide imaging such as a mercaptoacetyltriglycine (MAG 3) scan with the addition of a diuretic. Demonstration of functional obstruction by a T ½ of greater than 20 minutes with or without a differential function of less than 40% is the radiological indication for pyeloplasty.

Once the diagnosis has been made radiologically, the clinical indications for pyeloplasty are flank pain, recurrent upper urinary tract infection, development of renal calculi, and worsening renal function. Pain is often described after a significant fluid or diuretic challenge such as with alcohol or caffeine, known as Dietl crisis.

In the setting of a poorly or nonfunctioning kidney (<10% to 15% split function), observation or nephrectomy may be preferred. Other contraindications include all contraindications to robotic assisted/laparoscopic surgery, active infection, suspicion of an upper tract urothelial malignancy, and an intrarenal pelvis ( Table 22.1 ). ^,

Indications and contraindications for robotic pyelolithotomy and nephrolithotomy

Due to the lowering costs and the increasing ubiquity of robotic-assisted surgery in urologic practice, coupled with the rising incidence of stone disease, indications and application for the operating robot in upper tract stone surgery continue to evolve. Current guidelines for the management of large upper tract calculi are well established. Both the American Urological Association (AUA) and the European Association of Urology (EUA) recommend PCNL over URS or shock-wave lithotripsy (SWL) as first-line management for symptomatic stones greater than 20 mm and lower pole stones greater than 10 mm. ^, Traditionally, an open approach was utilized for stones not amenable to PCNL or with previously failed endoscopic extraction. Laparoscopic and subsequently robotic stone removal emerged as alternatives to an open approach, avoiding the morbidity of a large incision. These techniques have been utilized when stones and anatomic defects, such as PUJ obstruction, occur concomitantly. Despite mounting data, the precise indications for the use of robotics as a first-line approach for upper tract stones without reconstruction have yet to be fully codified.

The upper limits for PCNL with regard to stone size or density are not well defined, and a robotic approach has demonstrated efficacy for solitary large, hard, or complex upper tract stones. In 1994 Gaur et al. first reported on laparoscopic pyelolithotomy with a subsequent small series confirming its feasibility with concomitant PUJ repair. Robotic pyelolithotomy (RPL) series began appearing in the literature after 2005, with indications including concomitant upper tract reconstruction, failed prior intervention, and primary treatment for large staghorn stones without upper tract abnormality.

Staghorn kidney stones have one of the lowest clearance rates reported with PCNL and more often require multiple puncture sites which carry an increased risk of bleeding and need for transfusion. Badani et al. have demonstrated excellent results with primary robotic stone removal of staghorn calculi with particularly high clearance rates for partial staghorn stones. ^, Similar success for partial staghorn clearance has been shown in subsequent series. ^,

Infectious or struvite stones are very frequently staghorn in configuration. These stones have a high likelihood of sepsis and subsequent growth when fragments are left behind. As such, guidelines recommend that these patients be rendered completely stone-free. RPL traverses the renal pelvis providing a low-pressure system for stone extraction, potentially without fragmentation minimizing potential septic complications. Swearingen et al. demonstrated excellent efficacy for staghorn calculi, as well as one case of a gas-containing stone, where robotic removal was presumably chosen to mitigate fragmentation, and therefore infection risk.

Patients with large kidney stones and concurrent anemia and/or chronic kidney disease (CKD) may also be potential candidates for RPL, avoiding exacerbation of these comorbidities. Access through the renal parenchyma can decrease glomerular filtration rate (GFR) in preexisting CKD or when multiple puncture sites are needed and can cause bleeding due to the high vascularity of the kidney. ^{, ,} Several modern robotic series have reported excellent stone-free rates with minimal to no reduction in GFR and low transfusion rates. ^{, ,}

Another potential indication for RPL is large or complex stones in obese patients. While direct comparison studies have not been conducted, increased BMI can affect PCNL with longer operative times, inferior stone-free rates, and higher repeat intervention rates, while obesity has not demonstrated a difference in the outcomes of robotic renal surgery. ^,

Other, though less frequent, indications for upper tract robotic stone extraction include symptomatic anterior calyceal diverticulum with stones, ectopic kidneys with large stone burden not amenable to PCNL, and large impacted ureteral stones with or without concomitant strictures. These are relatively rare instances, and the decision to use the operating robot should be made on a case-by-case basis with the relevant anatomy and operating surgeon’s skill set considered.

A full list of indications for robotic stone removal can be found in Table 22.2 .

We do not recommend robotic stone surgery as first-line therapy for clinically straightforward stones less than 2 cm which meet well-established criteria for URS, SWL, or PCNL. Relative contraindications to RPL include large calyceal stones with narrow infundibula in the upper and/or lower pole, which present a challenge to robotic removal without fragmentation due to poor access and visualization. Complete staghorn stones with large calyceal components also demonstrated lower stone-free rates in multiple series. ^, In the largest series to date with RPL for primary stone removal, only 5 out of 70 patients required secondary procedures for incomplete removal; 4 out of those 5 were stones with some form of calyceal component. While robotic anatrophic nephrolithotomy has been described for complete staghorn stones, it is not recommended as it can be technically challenging with a potential for significant blood loss and a low reported stone-free rate of 28.6%.

Collecting systems with many dispersed stones can make complete clearance difficult with a robotic approach. Bedside pyeloscopy with laser lithotripsy can be performed through a robotic port. Roth et al. reported lower stone-free rate compared to other studies, as well as one instance of urosepsis. Notably, in this series, most patients had multiple stones, and concurrent endoscopy was performed which may have been the reason for the infectious complication. Nevertheless, multiple stones are likely best approached with other modalities of lithotripsy for the highest chance of success.

Further contraindications include lack of surgeon experience with the operating robot as well as patients with significant prior abdominal (or retroperitoneal) surgical history, scarring or fibrosis. When the surgeon can anticipate poor surgical planes, aberrant anatomy, and/or difficult robotic maneuverability intraoperatively, other approaches are best explored.

Preoperative assessment

Patients should be counseled on the risks, benefits, and alternatives to the proposed procedure as well as expected outcomes and potential complications. The need for a ureteric stent as well as common side effects should be thoroughly explained. The extent of preoperative blood work and the need for medical clearance will vary with a patient’s comorbidities; at a minimum, a basic metabolic panel and urine culture are necessary. A noncontrast computer tomography (CT) scan with three-dimensional (3D) reconstruction is imperative in planning renal stone surgery ( Figs. 22.1 and 22.2 ), particularly in cases where there is more than one stone. For pyeloplasty, a contrast study, either CT or magnetic resonance imaging (MRI), is essential to outline the relevant anatomy and identify any lower pole crossing vessels.

Staghorn in Renal Pelvis Axial.

Three-Dimensional Reconstructed Staghorn.

Patient preparation and positioning

The patient is induced under a general anesthetic and depending on the preoperative workup, either placed in lithotomy for cystoscopy and retrograde pyelogram or into a modified lateral decubitus position with gel roll supports posteriorly. The authors prefer to place a stent antegrade intraoperatively. The ipsilateral leg is extended and supported with a pillow and the contralateral leg is flexed with adequate padding beneath the knee and lateral malleolus of the ankle. The ipsilateral arm is draped over a pillow or in a gutter and secured with tape. The contralateral arm is extended on an arm board and an axillary roll placed if required. The patient is secured at the hips and thorax with tape. An upper body “Bair Hugger” is applied for warming. The patient’s abdomen is shaved and prepped to include the genitalia to allow access to the urethra intraoperatively. Draping is performed to allow exposure of above.

Port placement and robot docking: Transperitoneal approach

We favor a transperitoneal approach as this allows better access to the renal pelvis. Depending on body habitus and the extent of renal pelvis dilation, ports may be shifted slightly more caudal compared to a standard set-up for robotic renal surgery. In general, ports are placed in a straight line beginning at the lateral border of the rectus (about 6 cm lateral to the midline). For very thin/small patients, ports may be placed in the midline. For those with a larger body habitus, ports may be shifted laterally to the mid-clavicular line. A 5 mm or 8 mm AirSeal assistant port is placed through the umbilicus. Surgery is performed with insufflation set to 12 mmHg. The robot is docked perpendicular to the patient, ideally from the posterior aspect. A list of recommended equipment is provided in the box that follows.

Bowel mobilization

For patients with severe left hydronephrosis, a transmesenteric approach can be performed. The attenuated mesentery is incised and dissected off the underlying renal pelvis and ureter, taking care to avoid any mesenteric vessels. In the majority of cases, however, standard bowel mobilization is necessary in order to ensure adequate exposure. The bowel is medialized by dividing the peritoneum and large bowel adipose tissue lateral to the colon as it overlies Gerota fascia. Gentle blunt dissection is used to locate the proximal ureter and renal pelvis. Identification of the renal hilum is not always required but can help to avoid inadvertent injury to the renal vein during dissection of the renal pelvis. On the left side, the colon does not need to be dissected as extensively as for a partial or radical nephrectomy as long as there is adequate exposure to the PUJ; splenic mobilization is rarely required. On the right side, the liver may need to be elevated in order to provide adequate exposure. A laparoscopic grasper is passed through a subxiphoid incision and secured to the diaphragm; alternatively, this can be accomplished using a ProGrasp placed in the most cranial robotic port with the camera shifted caudally to the port lateral to the umbilicus. The duodenum should be identified and may or may not need to be kocherized depending on its relationship to the PUJ.

Pyeloplasty

The ureter is identified after the bowel mobilization along the psoas, medial to the lower pole of the kidney. Without skeletonizing the ureter, it is mobilized to the PUJ and the renal pelvis is dissected out. Care is taken to identify a crossing vessel and if one is found, it is advised to transpose the anastomosis anterior to the vessel/s.

Once the PUJ has been dissected out, using robotic Potts scissors, the PUJ is incised, and before completely transecting, the ureter is spatulated at least 1 cm in length on the lateral aspect. If there is redundant renal pelvis, this may be excised to ensure appropriate funneling and dependent drainage through the anastomosis. If a concurrent pyelolithotomy is being performed, a flexible cystoscope is introduced through the assistant port and stones are removed with a grasper or basket. Alternatively, depending on stone location, using the ProGrasp, the renal pelvis is held up and the camera can look directly in to remove the stones using robotic graspers.

To ensure the best possible set-up for anastomotic suturing, the authors use the ProGrasp on the periureteric tissue to hold up the ureteric end without grasping any urothelium. A stay-suture of 4-0 Vicryl can also be employed. The anastomosis is created using 4-0 Vicryl on a taper needle with the first suture placed at the apex of the spatulated ureter and the most dependent portion of the renal pelvis. The apex is the most crucial part of the anastomosis and, as such, the authors prefer to place three interrupted sutures to ensure a watertight closure. The posterior wall is then closed in a running fashion. At this point a 6 Fr double J ureteric stent is placed over a guidewire in an antegrade fashion. Using a 16 Fr flexible cystoscope, the distal coil of the bladder is confirmed. The proximal coil is then placed in the renal pelvis and the anterior wall is closed in a running fashion.

Pyelolithotomy and nephrolithotomy

Port placement, docking, as well as bowel mobilization are identical to robotic pyeloplasty and are described above. A retroperitoneal approach has been described for RPL; however, we do not advocate this technique for the same reasons we do not recommend it for robotic pyeloplasty (described above). In the case of robotic stone surgery, longer operative times and increased blood loss were reported with a retroperitoneal approach.

Renal pelvis identification and stone extraction

Once the bowel is medialized, the ureter is identified, isolated, and mobilized up to the renal pelvis. Subsequent dissection of the renal pelvis from all its surrounding tissue and fat is performed. Surrounding tissue may be inflamed secondary to the renal stone, chronic infections and/or prior attempts at management; therefore a slow methodical dissection should be undertaken. Care is then used to identify and preserve the renal vessels which, in a transabdominal approach, will lie anterior and cranial to the pelvis itself.

Using Potts scissors, the renal pelvis is then opened. The extent of the incision is dependent upon the size and location of the offending calculi. The stone is dissected free from the tissue and extracted, ideally intact ( Fig. 22.3 ). The specimen is then placed in an EndoCatch bag to avoid losing fragments intraabdominally. If smaller stones are present these can be handed to the bedside assistant and removed with a laparoscopic grasper. Relevant imaging should be available in the operating room to confirm the stones removed are consistent with the location, shape, and burden seen on imaging. Additionally, intraoperative ultrasound can also be used as needed to help identify stones in the collecting system. The renal pelvis is then inspected to ensure no further stones are found, and subsequent irrigation can be used to flush out any remaining pieces. If there is concern for remaining stones, flexible nephroscopy with or without laser lithotripsy with basket extraction can be performed by the bedside assistant. A double J ureteric stent is then fed antegrade over a wire down to the bladder. The wire is removed, and the proximal curl placed in the renal pelvis. The renal pelvis is then closed with a running 3-0 absorbable suture with care taken to avoid passing the suture through the proximal curl of the ureteric stent. The kidney is then placed back in the retroperitoneum which is then closed with a 3-0 suture. A Blake/Robinson drain is placed adjacent to the closed pyelotomy. The specimen is then extracted with a small, extending incision of the assistant port site.

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