Transperitoneal Robot-Assisted Laparoscopic Pyeloplasty *

Abstract

Minimally invasive pyeloplasty has achieved success that has approached open pyeloplasty. Key principles such as removal of fibrosis, extensive mobilization of the ureteropelvic junction and crossing vessels, and creation of a tension-free, widely spatulated anastamosis are important in successful repair. In this review, we discuss the preparation and operative steps in performing a robotic pyeloplasty. Patient selection and diagnostic approach is discussed in the preoperative setting. Important surgical steps described include port placement, management of crossing vessels, division and spatulation of the ureter, and reanastamosis. Finally, management of more difficult cases is discussed.

Introduction

W ith the development of robot-assisted surgery, the option for minimally invasive pyeloplasty has become more widely available. Recent evidence shows that robot-assisted and laparoscopic pyeloplasty have approached the success of open pyeloplasty,^1
–3 while offering the potential for shorter recovery time and reduced postoperative pain.^4
–6 In addition, long-term follow-up of patients who were undergoing other forms of minimally invasive treatment for ureteropelvic junction obstruction (UPJ)—in particular, endopyelotomy—has shown an increased risk of failure or recurrence relative to a pyeloplasty.⁷ Despite its success, factors in patient selection and operative technique can influence the outcome of robot-assisted pyeloplasty. In this article, we review technical aspects of patient selection, operative preparation, and the surgical steps of robot-assisted pyeloplasty.

Indications and Contraindications

Patients who present with a diagnosis of UPJ obstruction should be offered robot-assisted pyeloplasty as a primary therapy. The gold standard for management of UPJ obstruction has been open pyeloplasty, which has reported 90% to 95% success rates.^8,9 Recent reports suggest that robot-assisted pyeloplasty has equivalent success rates.^3,5 Minimally invasive surgery also offers the additional advantage of decreased postoperative pain and shorter convalescence in many of the adult series.^3,5,6 As an alternative to minimally invasive pyeloplasty, endopyelotomy has a lower success rate of 60% to 80%.^7,10 It has thus fallen out of favor as first-line therapy for primary UPJ obstruction, but it is still often used in secondary UPJ obstruction or for patients who are poor operative candidates.

Patients who present to the urologist for management of UPJ obstruction often have imaging that suggests hydronephrosis without hydroureter. If the patient is asymptomatic with stable hydronephrosis and renal function, it is appropriate to observe the patient. Patients often present, however, with pain that is thought to be of renal origin that is recurrent or limiting to daily activity. Other indications, usually in addition to pain, to treat patients with UPJ obstruction include worsening renal function on renal scans, evidence for worsening obstruction on imaging, history of urinary tract infections, nephrolithiasis in the affected kidney, or hematuria.^11
–13

Minimally invasive pyeloplasty or any corrective intervention of UPJ obstruction is contraindicated in the setting of active urinary tract infection. Another contraindication to pyeloplasty would be in the setting of an upper tract urothelial carcinoma.¹² Relative contraindications include a long stricture (3 cm or larger). In addition, a small, intrarenal pelvis can make minimally invasive pyeloplasty, especially dismembered pyeloplasty, extremely difficult. In these cases, one must consider an open pyleoplasty or a ureterocalicostomy. In some of these situations, a Fenger plasty or Y-V plasty could be considered. Finally, patients with a poorly functioning kidney and significant symptoms should be considered for laparoscopic nephrectomy.¹²

Preoperative Evaluation

Patient history should determine whether he or she has had any previous urinary tract infections, stones, or hematuria. One should also inquire about previous surgeries or traumas. Although some urologists, especially in pediatrics, prefer ultrasonography to identify hydronephrosis, CT is more accurate in identifying stones. Delayed phase CT with intravenous contrast can also identify an upper tract urothelial lesion if the history raises suspicion of one. CT angiography can be used to help identify lower pole crossing vessels (90% accuracy in a previous series).¹⁴ A functional study, such as a mercapto acetyl triglycine renal scan, which can measure differential renal function and renal drainage, can confirm obstruction and monitor for decline in renal function.¹⁵ A baseline radionuclide renal scan is also useful when following the patient postoperatively.

The patient should have a preoperative urine culture performed and infections treated. If the patient has signs of impending sepsis, drainage with either a stent or nephrostomy tube should be considered. Although patient convenience may make stents preferable, a stent can make additional evaluation of the UPJ difficult. A nephrostomy tube can be used to perform antegrade nephrostography. Other laboratory evaluations include serum creatinine levels, blood counts, and basic coagulation studies.

Diagnosis of UPJ obstruction can have some pitfalls. In patients who have large renal pelvic stones, the stone itself or the inflammation from the stone can obstruct the UPJ, giving the appearance of a primary UPJ obstruction. The stone should be removed, usually via a percutaneous nephrostolithotomy, after which the UPJ can be more fully evaluated. In symptomatic patients with equivocal obstruction on renal scan (T1/2 of 15–22 minutes), placing a nephrostomy tube to relieve symptoms or to perform a Whitaker test can identify surgical candidates. Treatment of symptoms in this manner can help confirm the diagnosis of a symptomatic UPJ obstruction. For patients in whom abnormal anatomy or urothelial lesions are suspected, retrograde pyelography or ureteroscopy may be indicated.

Preoperative Preparation

Before surgery, a negative culture should be confirmed and all urinary tract infections appropriately treated.¹² Female patients should have a negative urine pregnancy test. The possibility for coagulopathy should be ruled out. The afternoon and evening before surgery, the patient should be limited to a liquid diet and should abstain from oral intake after midnight. A bottle of magnesium citrate is taken the afternoon before surgery. Just before surgery, under the same anesthetic, retrograde pyelography is performed at our institution. A retrograde pyelogram can elucidate stricture length, pelvic anatomy, distal obstruction, and filling defects that may preclude pyeloplasty. At this time, a stent may be placed up the ureter of interest or, alternatively, this can be placed in an antegrade fashion after dividing the UPJ.

After administration of anesthesia, the patient is positioned on the table in a modified flank position, with the affected kidney up at a 45-degree angle. A beanbag or rolls are used to help support the patient in this position. The umbilicus is placed at the break of the table. Moderate flexion of the bed can drop the upper arm, which is resting on an armrest or pillows, to allow more room for the upper robotic arm. The lower arm (opposite the kidney of interest) is placed on an arm board extended perpendicular to the body. An axillary roll is placed just inferior to the axilla. The upper leg is extended at the hip and knee, while the lower is flexed at the knee. Padding is placed underneath the lower knee and ankle, and pillows are placed between the legs to support the upper leg. The patient is secured to the table with tape applied below the knee, at or just below the hip, and just below the nipple line. The head end of the operating table is rotated, if needed, toward the patient side cart, which is then brought over the patient's chest and shoulder.

Instrumentation

Two 12-mm bladeless, disposable trocars are used (one for the assistant port and one for the robotic camera). Alternatively, one could use reusable ports. Two 8-mm robotic trocars are used. An additional 8-mm trocar can be used if a robot's fourth arm is used. We have found three robot arms (one for the laparoscope and two for the instruments) adequate. For right-sided pyeloplasties, a 5-mm epigastric trocar can be used for liver retraction.

The daVinci^® Surgical System (Intuitive Surgical, Sunnyvale, CA) robot is used. In the right arm, the robotic endoshears, reusable up to 10 times, is placed, and, in the left, the PK dissector. Alternatively, a hook cautery could be used in the right hand and/or a fenestrated bipolar in the left. Robotic Potts scissors are used for dismemberment. Large needle drivers are used for anastomosis. Alternatively, a robotic fine tissue forceps can be used for gentler handling of tissues. Usually, the anastomosis is completed with a 4-0 or 5-0 polyglactin suture on an RB-1 needle. The assistant uses a suction irrigator (nondisposable tip) to provide exposure.

Surgical Steps

Port placement

Intraperitoneal access is obtained through the umbilicus using the Veress needle technique, but the Hasson technique may also be used. The table is rotated so that the patient is nearly flat during initial access. A 12-mm trocar is placed under direct vision using a bladeless trocar after the abdomen has been inflated to 15 mm Hg. After initial port placement, the table is now rotated until the patient is at 90 degrees with the floor. If a liver retractor is needed, a 5-mm port placed subxyphoid should be placed before rotating the table to the lateral position. A second 12-mm port is placed laterally 1 to 2 cm below and medial to the tip of the 12th rib, which is used for the robotic camera. Alternatively, in a modified lateral camera postion, the camera port is placed more medially, at the level of the midclavicular line, approximately in-line with the other robotic ports.

Two 8-mm ports are placed: One is placed 2 cm below the costal margin in the midclavicular line, or just medial to this. The other is placed two fingerbreadths above the iliac crest, slightly more lateral to the midclavicular line. A fourth robotic arm, if necessary, can be placed medially and inferior to the lower robotic arm. Alternatively, by transposing the lower of the two 8-mm trocars superiorly and medially, one could place the fourth arm in the anterior axillary line and above the iliac crest. With this lateral camera configuration, one will predominantly use a 30-degree up lens. If one were instead to place the camera at the umbilicus, then a 30-degree down lens would be used (Fig. 1).

FIG. 1.

Port placement for robot-assisted pyeloplasty.

Mobilization of the ureter and pelvis

The first step in identifying the ureter and renal pelvis is to reflect the colon medially, especially on the left. Alternatively, in smaller children and patients without much mesenteric fat, a transmesenteric approach can be used. After sufficient mobilization, the gonadal vein is identified a few centimeters below the lower pole of the kidney. The fascia of the psoas muscle should be identified next. While staying anterior to the fascia, dissection in the region of the gonadal vein will identify the ureter. The ureter should be freed from surrounding fibrotic tissue, but should not be skeletonized, in a proximal direction. Holding the ureter gently up can aide in dissection.

Care should be taken as one approaches the lower pole to identify lower pole vessels. Occasionally, the retroperitoneal or perirenal fat is abundant and makes exposure of this region difficult. Retraction sutures or a fourth arm can be used to retract this tissue laterally. Retraction sutures are 2/0 polyglactin sutures that are used to suture the peripelvic fat to the tissue more laterally placed or to the Gerota fascia. These sutures are divided at the end of the surgery. Once the pelvis is reached, it should be freed from surrounding tissue up to the level of the primary renal vein.

Mobilization of the lower pole vessels

Lower pole renal vessels have been identified in up to 20% to 50% of adults who present with primary UPJ obstruction.¹³ Early identification of these vessels is important to avoid injury. Using blunt dissection, these can be lifted off the UPJ. The attachments to the vessels should be removed along the course of the artery. The lower pole vein can be divided occasionally to provide further mobilization of the artery, if necessary. A meticulous and wide mobilization of the lower pole crossing vessels is essential to ensure that the vessels can be transposed easily, if needed (Fig. 2).

FIG. 2.

Mobilization of crossing vessels.

After division of the UPJ, the proper positioning of the lower pole artery should be tested before reanastomosis, because transposition posteriorly may not always be indicated. In two recent series of 23 and 30 patients with nontransposed crossing vessels, respectively, the success rate was similar to those undergoing transposition.^16,17 Occasionally, posterior transposition increases tension on the anastomosis, in which case, superior transposition may be better.

Division of the UPJ

Incision of the UPJ is started on the medial pelvis, about 2 cm above the UPJ. The incision is lengthened on the anterior surface of the pelvis, extending laterally with an inferiorly directed angle so that the ureter is reached at the UPJ with the incision. An oblique division of the pelvis is therefore produced. Spatulation then occurs at the lateral portion of the ureter for about 1 to 2 cm. The length of the spatulation may be increased, depending on the redundancy of the proximal ureter and the pelvis to ensure a tension-free anastomosis. Performing this spatulation with the posterior wall of the UPJ intact can help properly direct the spatulation. Finally, the posterior wall is divided in an angle parallel to the anterior wall.

The placement of stay sutures during the division of UPJ can improve one's ability to properly direct the incisions while minimizing trauma to the tissues (Fig. 3). A total of three retraction sutures are placed: The first on the medial pelvis, above the line of incision; the second, on the medial ureter below the incision line (in the area of excess stenotic ureter that will be removed); and the third, on the lateral pelvis. Traction on the medial pelvic retraction suture can help during division of the anterior and posterior walls of the UPJ. Traction of the lateral pelvic retraction suture can help with lateral spatulation of the ureter.

FIG. 3.

Placement of stay sutures around the area of division and reanastomosis.

Reanastomosis

For the left-sided pyeloplasty, suturing starts at the ureter in an out-to-in fashion at the vertex of the lateral spatulation. The suture is then passed in-to-out on the dependent lateral pelvis, and the knot is tied. The suture is passed underneath the anastomosis to complete the posterior wall. By throwing a suture in an out-to-in direction on the pelvis, the suture line is now arranged in a very ergonomic fashion for completing the posterior anastamosis (suturing in-to-out on the ureter and out-to-in on the pelvis). At the most medial point, the suture is ended with the needle on the outside of the ureter. The anterior suture is completed in a lateral to medial fashion starting on the ureter. The anterior and posterior sutures are tied together at the medial side of the anastomosis.

In the case of the right-sided pyeloplasty, the suture is begun on the dependent, lateral pelvis (out-to-in) and sutured through the vertex of the ureteral spatulation (in-to-out). After passing the needle posteriorly, a similar reversal stitch can be placed through the ureter to arrange the posterior suture line for ergonomic right-handed suturing. At the medial side, this suture line ends with the needle on the outside of the pelvis.

Before anastomosis, suctioning out the pelvis can remove any clots that may later obstruct the kidney, leading to urine leakage. Using stents with multiple holes at the ends along with minimizing grasping of the ureteral stent during anastomosis with the robotic instruments can minimize stent obstruction. Finally, when placing the stent either retrograde or antegrade, use a stent that is a size longer than what is measured or calculated. This allows for some movement of the stent without the risk of migration of the distal stent into the distal ureter. We typically use a stent that is 4 cm longer than the length of the ureter from the UPJ to the ureterovesical junction measured at the time of retrograde pyelography before laparoscopy.

Difficult scenarios

After dismemberment, if tension is expected at the anastomosis, further mobilization of the ureter and the pelvis would be needed. Occasionally mobilization of the entire kidney to facilitate caudal displacement may be necessary.

In patients with little or no redundant pelvis, a dismembered pyeloplasty could be difficult. Because there is no extra pelvis, the ureter cannot be widely spatulated to increase the diameter of the anastomosis. In this situation, a Foley Y-V plasty or Fenger plasty could be used. In the laparoscopic case, moving the lateral and medial segments of the Y-incision slightly anterior facilitates reconstruction. Conversely, in large, redundant pelvises, the region superior and lateral to the anastomosis can be excised.

A high ureteral insertion can be dealt with by dividing the UPJ and transposing the ureter to the inferior and medial position on the pelvis. This can be done by making an entirely separate incision, or by extending the excision line laterally, depending on the distance. Patients with a long ureteral stricture and redundant pelvis could be treated with a Culp-DeWeerd flap, which brings a flap of the pelvis down to cover a spatulated but not completely divided ureter.

In the horseshoe kidney, there are often several aberrant vessels present, making this procedure difficult. In addition, the kidney is often rotated such that the pelvis is more anteriorly placed, relative to the parenchyma. In a series of three patients, Chammas et al¹⁸ describe spatulation on the posterior aspect of the ureter.¹⁸ A case report demonstrates successful laparoscopic repair of a retrocaval ureter that is often repaired in an open fashion.¹⁹ The UPJ was dismembered at the lateral edge of the cava, and the ureter was mobilized medial to the vena cava for reanastomosis and excision of the atretic portion.

Postoperative Care

At the end of the procedure, a drain is place through one of the 8-mm ports and positioned near but not directly on the anastomosis. This is connected to bulb suction. Fascial closure of the midline 12-mm port should be done. In patients who are at risk, the fascia of the laterally placed 12-mm port can also be closed. The patient is transferred to the ward with a urethral catheter and a drain. With a stent in place, the catheter ensures that the bladder stays at low pressure to avoid reflux of urine back up the ureter and contributing to a potential leak.

The patient is allowed to ambulate and eat a regular diet on postoperative day 1. If the drain output is moderate, the urethral catheter is removed. The drain is monitored for approximately 4 hours or at least one void, and fluid is sent for measurement of creatinine. If it is normal, the drain is removed, and the patient is discharged. The stent will remain in place for 4 to 6 weeks. Six weeks after stent removal, a renal scan is obtained to evaluate drainage and function. We then follow the patient with renal scans 6 months and 18 months later, assuming the patient is asymptomatic.

Complications

The intraoperative complication rate for robot-assisted pyeloplasty is rare, 0% to 2%, including minor complications and elective conversions.^{3,7,20

–24} Splenic and hepatic lacerations can occur when robotic instruments are exchanged while off-screen. Usually coagulation with the PK or bipolar or hemostatic adjuncts and pressure is sufficient for control. Bowel injuries, if inflicted without heat and small in size, can be repaired robotically by oversewing them, assuming there has not been gross spillage of bowel contents. Otherwise, these necessitate open management. Vascular injuries are exceedingly rare and may also lead to open conversion.

Postoperatively, the patient is carefully monitored for urine leakage, which may occur in less than 2% of cases.^20

–23 Perioperative complications have occurred in 3% to 11% of cases.^20

–23 If a urine leak occurs shortly after the procedure (within 1–2 h), abdominal radiography can confirm the position of the ureteral stent. Distal migration of the stent up the ureter may necessitate ureteroscopy and basket retrieval of the distal end. Disruption of the anastomosis will likely necessitate reoperation.

Obstruction of the stent or ureter with debris or kinking can occur early or later on. Initial conservative management may allow edema from the procedure to subside, thereby relieving the obstruction. If the obstruction leads to worsening pain and leakage, the stent may have to be exchanged. Alternatively, a nephrostomy tube could be placed. Postoperative urinary infections should be managed with antibiotics aggressively. A longer course of antibiotics of 2 weeks, depending on the severity of the infection, may be indicated because of the indwelling stent. If signs of sepsis continue despite proper urinary drainage and antibiotics, an abscess or infected urinoma should be assessed with a CT scan.

Results

In a recent meta-analysis of the success rate of robot-assisted and laparoscopic pyeloplasties, both modalities had a success rate of 88% to 100%, with the majority of series better than 95% (Table 1).² In a multi-institutional review of 865 patients from 15 centers in the Robotic and Laparoscopic Pyeloplasty Collaborative Group, Kaplan-Meier analysis revealed a 97.2% 1-year and 94.5% 2-year freedom from secondary procedure in 485 robot-assisted pyeloplasties.²⁵ Pain improved in 95.4%, and obstruction improved in 96.8%.

Table 1.

Outcomes for Robot-Assisted Pyeloplasty

Series	N	OR time (min)	Intraoperative complications	Success	Postoperative complications
Mufarrij 2008²⁰	140	217	1 minor splenic injury	Radiologic: 95.7% Symptom: 92. 4% 2nd procedure: 4.3%	2 urine leaks 7% major (7/10 stent problems)
Schwenter 2007²¹	92	108^a	0	Radiologic: 96.7% 2nd procedure: 3%	3 urine leaks
Gupta 2009 ²²	86	121	2 conversions	Radiologic: 96.5% 2nd procedure: 2.3%	3 urine leaks, 1 port site hernia, 1 volvulus
Patel 2005²⁴	50	122	0	Radiologic: 100% 2nd procedure: 0	1 readmitted for colic, stent placed, removed w/o pain
Palese 2005²³	38	225	0	Radiologic: 94.7% 2nd procedure: 5.3%	0 leaks 4 complications
Yanke 2008⁷	29			Radiologic: 100%2nd procedure: 0
Olsen 2007²⁶ (pediatric)	67	142	1 conversion	Radiologic: 95.5%Symptom: 98.4%2nd procedure: 5.9%	4 temporary PCNs, 2 UTIs
Sethi 2010²⁷	52	212		Radiologic: 92%Symptom: 96%	4 complications
Lucas, Sundaram 2010²⁵	485	204	1.9%	Radiologic: 96.8%Symptom: 95.4%2nd procedure: 3.8%	Urine leaks 1.8%Postop complications 5.4%

Time estimated from docking to completion.

OR = operative; PCN = percutaneous nephrostomy; UTI = urinary tract infection; postop = postoperative.

Conclusion

Robot-assisted pyeloplasty is effective for the treatment of patients with UPJ obstruction with a low rate of complication. Appropriate patient selection and preoperative preparation is necessary to maximize results. A stepwise approach of mobilization, division with wide spatulation, and a tension-free, watertight anastomosis are key steps in robot-assisted pyeloplasty.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

Appendix

List of Instruments

Instrument	Manufacturer	Number of uses
da Vinci Large Needle Driver (2)	Intuitive Surgical, Inc.	10
da Vinci Fine Tissue Forceps	Intuitive Surgical, Inc.	15
da Vinci Hot Shears	Intuitive Surgical, Inc.	10
da Vinci PK Dissecting Forceps	Intuitive Surgical, Inc.	10
da Vinci Potts Scissors	Intuitive Surgical, Inc.	10
Stryke Flow 2 suction irrigator	Stryker	Disposable pump Reusable metal tip

*

A coordinating article with video is available in Videourology 25/1 at www.liebertonline.com/vid/doi/full/10.1089/vid.2010.0150

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