Robot-assisted laparoscopic pyeloplasty: A retrospective case series review.

INTRODUCTION: Anderson-Hynes pyeloplasty has been gold standard in the management of pelviureteric junction obstruction (PUJO). It has evolved from open to laparoscopic and now robotic surgery. Open surgery has its drawback of long incision and scar mark, significant post-operative pain and long hospital stay. The main limitation of laparoscopic surgery had been the difficulty in endosuturing. Robotic surgery has incorporated the minimal access method of laparoscopy and endowrist movement of open surgery to overcome the challenge of intracorporeal suturing. Here, we present our initial experience of robotic pyeloplasty. PATIENTS AND METHODS: A total of 30 patients underwent robot-assisted laparoscopic pyeloplasty (RALP) over 19 months. Diagnosis of PUJO was made by computed tomography urography, diuretic renogram and retrograde pyelogram in selected patients. All patients underwent RALP by colon reflecting approach. Post-operative evaluation was done by DTPA scan at 3- and 6-month follow-up. Data were analysed after a mean follow-up of 11 months.
RESULTS: The mean operative time was 148 min and the mean hospital stay was 3.5 days. While 93% of the patients showed objective improvement in their drainage pattern on DTPA renogram, 90% of the patients were symptom-free at the end of 6 months.
CONCLUSIONS: Robotic pyeloplasty is a safe and easily conquerable technique with comparable outcomes in the hands of surgeons who are beginners in this technique.

INTRODUCTION

Incidence of congenital ureteropelvic junction obstruction (UPJO) is one in 500 live births.[1] Most of the congenital pelviureteric junction obstructions (PUJOs) are intrinsic in nature where a normal spirally arranged smooth muscle is replaced by either longitudinally arranged smooth muscle or collagenous tissue. The patient may be asymptomatic and present later in life with pain, hydronephrosis and decline in renal function.[2] The gold standard treatment of PUJO has been dismembered pyeloplasty (Anderson Hynes [AH]). Although antegrade and retrograde endoscopic pyelotomy was introduced at some point of time, it has fallen back because of its limited success.[3] In 1993, Schuessler et al. first demonstrated the laparoscopic approach for pyeloplasty with similar outcome and low morbidity compared to the gold standard modality of open pyeloplasty.[4] Robotic surgery came into practice in 2000. Gettman et al.[5] were the first ever to report the series of pyeloplasty done by robot in 2002. Robotic surgery has several advantages such as short learning curve, three-dimensional (3D) vision and precision in tissue handling and suturing. A meta-analysis indicated that robot-assisted pyeloplasty has higher success rate as compared to laparoscopic approach with reduced complication and re-intervention rates.[6] A formal training in laparoscopy is not mandatory to start robotic surgery because different skills are required in these two minimal access methods of surgery.[7] This fact was consolidated by our study. We present our experience of initial 30 cases of robot-assisted laparoscopic pyeloplasty (RALP) done at our institute.

PATIENTS AND METHODS

A retrospective analysis of RALP done from March 2018 to October 2019 was carried out. A total of 30 patients comprising 18 males and 12 females underwent RALP. The mean age was 29 years (range: 15–48 years). Majority of the patients presented with pain in the flank. The diagnosis of PUJO was based on the standard imaging such as computed tomography (CT) urography and diuretic DTPA renogram. All patients having significant obstruction (t½ >20 min) or equivocal obstruction (t½: 10–20 min) with symptoms underwent RALP.

Surgical technique

Retrograde pyelogram was performed in selected patients such as equivocal diagnosis, prior surgical intervention and secondary UPJO. After the induction of general anaesthesia, a 16 Fr catheter was placed in the bladder and it was clamped to facilitate a later antegrade ureteral stent placement. The patient was positioned in the lateral position with target kidney on upside. Pneumoperitoneum is created with Veress needle. Port sites are marked in straight line in the para-umblical line. Three 8-mm ports (one camera and 2 working) are placed at 8 cm distance from each other starting 2 cm below the hypochondrial line. An assistant port is placed 2 cm below the line joining the camera and working port. An additional 5-mm port is placed in case of the right pyeloplasty to facilitate retraction of liver. Robot (Da Vinci Xi, Intuitive Surgical, Sunnyvale, CA, USA) is docked from back [Figure 1]. All cases were done by transperitoneal route by colon reflecting approach. Colon is reflected medially by incising the white line of Toldt. Limited dissection is done just enough to expose the dilated pelvis and help mobilisation of the ureter. Pelvis is transected about 1 cm proximal to ureteropelvic junction. Any accessory lower pole renal artery is preserved, and transected pelvis is transposed anterior to it. Redundant pelvis is excised. Ureter is spatulated for approximately 1 cm on the lateral side. The small segment of the pelvis attached to the upper ureter is used for tissue handling and is excised once the ureter is anastomosed to the pelvis. Anastomosis of most dependent portion of transected pelvis to the apex of spatulated ureter is done first. It is followed by suturing of the posterior layer with 4-0 vicryl. Antegrade double J (DJ) stent is placed over a guidewire. Now, closure of the anterior layer and pelvis is done. Drain placement was optional. Perurethral catheter is removed on day 1, and the patient was generally discharged on day 2 after removal of drain if it is <50 ml. DJ stent is removed after 4 weeks, and diuretic renogram is performed after 3 and 6 months. Data were analysed after the last follow-up.

Figure 1

Port placement and robot docking from back

RESULTS

A total of 30 patients underwent RALP. Fifteen had the procedure on the left and the rest 15 on the right. All dismembered pyeloplasties were done through a transperitoneal colon reflecting approach. The data were analysed for robot docking time, dissection time and anastomosis time. No patients required blood transfusion. The mean blood loss was 60 ml. All cases were completed robotically without any conversion to open. Perurethral catheter was removed after 1 day, and the drain was removed after 2 days in all except two cases in which perurethral catheter was reinserted while the drain was kept for ≥2 days because of urinary leak. Both of these patients were managed conservatively without any additional surgical intervention. One of these patients had renal pelvis injury repaired primarily intra-operatively while another was a known case of nephrotic syndrome who inadvertently took diuretic in the post-operative period. The mean hospital stay was 3.5 days (range: 2–12 days).

The varied intra-operative findings were duplex collecting system with lower moiety UPJO and crossing vessel in one, concomitant renal stones in six, lower pole crossing vessels in 12, horseshoe kidney in one, secondary UPJO in two (both after endoscopic renal surgery) and malrotated kidneys in four. In the patient of duplex collecting system with lower moiety UPJO, the length of lower moiety ureter and stricture segment was not much evident on CT urography. A pre-operative retrograde pyelography was very helpful in delineation of exact confluence of the lower pole ureter and its length [Figure 2]. Careful dissection with preservation of the upper moiety ureter and dismembered pyeloplasty of lower moiety was done. In two patients of PUJO with malrotation, nephropexy was done as ureter crossing over the lower pole of hydronephrotic kidney was causing tenting of ureter. Here, lower pole was mobilised and fixed to the abdominal wall laterally so that there is no longer tenting of ureter. Stone retrieval in six patients was accomplished with the help of flexible scope and laser lithotripsy. Of these six patients, two had residual stone located in a difficult to access calyx and both underwent percutaneous nephrolithotripsy at later date with complete stone clearance. In patients with crossing vessels, transposition of the pelvis anterior to the crossing vessel was done after dismembering pelvis from the ureter [Figure 3]. One patient had a lower polar crossing vessel, but it was located superior to the transition point between dilated pelvis and non-dilated ureter. Because it was not compressing pelviureteric junction (PUJ), AH pyeloplasty was done without transposition of vessels.

Figure 2

Retrograde pyelogram showing duplex renal pelvis

Figure 3

(a) Crossing vessel, (b) stone retrieved

The mean follow-up was 11 months, with a success rate of 93.3% [Table 1]. Two patients showed persistent obstruction on a diuretic renogram and CT urogram. Of these two patients, one had secondary PUJO after an endoscopic procedure while another patient had pre-operative infected hydronephrosis and required percutaneous nephrostomy before pyeloplasty. Subsequently, both patients underwent retrograde laser endopyelotomy. There were four patients with poorly functioning kidney who improved clinically and on diuretic renal scan.

Table 1

Patient variables

Variables	Mean (range) or n
Number of patients	30
Age (years)	29 (15-48)
Male/female	18/12
Symptoms
Pain only	28
Pain and swelling	1
Pain and pyelonephritis	1
Incidental findings	0
Side
Right	15
Left	15
History of previous intervention	2
Primary PUJO	28
Secondary PUJO	2
Associated conditions
Opposite side PUJO	2
Malrotated kidney	4
Horseshoe kidney	1
Stones	6
Lower pole crossing vessels	12 (both artery and vein-3)
Giant hydronephrosis	2
Partial duplex system	1
Poorly functioning kidney	4
Solitary kidney	2
Docking time (min)	9 (5-15)
Operative time (min)	140 (80-240)
Blood loss (ml)	60
Conversion to open (%)	0
Duration of stay (days)	3.5
Drain removal (days)	2
PUC removal (days)	3
Complication
Intraoperative	1
Post-operative urinary leak	2
Success, n (%)	28 (93.3)
Failure, n (%)	2 (6.7)
Persistent PUJO	2
Symptomatic	3
Non-functioning kidney	0
Mean follow-up in months (range)	11 (3-20)

PUJO: Pelviureteric junction obstruction, PUC: Perurethral catheter

DISCUSSION

The gold standard management of PUJO is dismembered pyeloplasty (AH). Several other options exist for the management of PUJO such as Foley's Y-V plasty, Culp-DeWeerd spiral flap pyeloplasty, Scardino Prince pyeloplasty, Davis intubated pyeloplasty and endopyelotomy. The specific indications are dependent on configuration of the dilated renal pelvis and position of the ureter in relation with the renal pelvis. Dismembered pyeloplasty and other flap pyeloplasty can be accomplished by open, laparoscopic and robot-assisted laparoscopic methods. Both transperitoneal and retroperitoneal approach have been described for doing these surgical procedures. However, the most commonly performed surgery is transperitoneal dismembered pyeloplasty.[28910111213]

Minimal access method is increasingly being utilised for performing dismembered pyeloplasty. First laparoscopic pyeloplasty was performed by Schuessler et al. in 1993.[4] Gettman et al. were the first to publish large case series of robotic pyeloplasty in 2002.[5] Several advantages of robotic surgery have been described. These are 3D vision with magnification, 7 degrees of freedom of movement, fine movement with scaling of motion and filtering of tremors of surgeon's hand, absence of fulcrum effect and thus lessened trauma to the patient at the port site, less surgeon fatigue and better ergonomics. Not only this, but robotic surgery also helps in precise dissection, accurate tissue handling and swift suturing. Disadvantages include cost in terms of investment and consumable instruments, bulky set-up and lack of haptic feedback.[10]

Most surgeons perform pyeloplasty transperitoneally because of familiarity with the anatomy and availability of large working space. Gupta et al. have described colon reflecting approach for the right and transmesocolic approach for the left side. We performed all cases by colon reflecting approach on both sides.[13]

General principle of any ureteral surgery applies during pyeloplasty as well i.e. careful mobilisation of ureter sparing adventitia, spatulated, tension-free, stented and watertight anastomosis. Moreover, an anastomosis should be widely patent, at the dependent position and well funnelled. We also insisted to these principles.[14]

Although there is no consensus on the definition of complicated PUJO; concomitant multiple calyceal stone, malrotated kidney, horseshoe kidney, ectopic kidney, secondary PUJO, giant hydronephrotic kidney, small intra-renal pelvis, duplex pelvis and long strictures are considered complex PUJO.[1516]

We also encountered one case of duplex pelvis with lower moiety PUJO, six cases of PUJO with stone, two patients with secondary PUJO, four patients with poorly functioning kidney (differential renal function [DRF] <20%) and two patients with giant hydronephrosis. All these complex cases were treated successfully. Renal stone extraction during robotic pyeloplasty is challenging. It was accomplished by the use of flexible scope simultaneously. We encountered difficulty in doing it because of logging of irrigant fluid in the peritoneum, which caused fogging and wetting of camera. The air seal device got chocked by irrigant fluid and it needed to be changed. Another difficulty was damage of sealing sleeve of flexible scope in two cases while directing the scope to the desired calyx by robotic instrument. It occurred because of lack of haptic feedback, and hence, the application of undue force by robotic instrument on the flexible scope.

Gnech et al. have found that pyeloplasty in a poorly functioning kidney (DRF <20%) is not associated with increased morbidity, and DRF remains either unchanged (45%) or improve (36%) after pyeloplasty.[17] Therefore, preservation of the kidney is always advisable. We did pyeloplasty in four patients with poorly functioning kidney (DRF at least 15%), and on 6-month follow-up, patients are doing well.

Presence of crossing renal vessels (CRVs) described in the literature has been in 26%–100% of case series.[18] In our study, it was noted in 12 (40%) patients. Three patients had both artery and vein present as crossing vessel at the lower pole of the kidney. Crossing vessels are not always the cause of PUJO. This phenomenon is one of the conditions where dismembered pyeloplasty has clear advantage over endopyelotomy and other non-dismembered flap procedures. Endopyelotomy was introduced in 1984 by Ramsay et al. and later popularised by Badlani et al.[1920] Conlin have found that endopyelotomy is successful in 94% of patients without crossing vessel and success rate decreases to 70% if crossing vessel is present. They advocated that endopyelotomy should be avoided in patients with crossing vessel >4 mm.[21]

Presence of crossing vessel can be known pre-operatively by colour Doppler, contrast-enhanced CT or magnetic resonance urography (MRU).[22] Weiss et al. have found that MRU has 88.2% sensitivity and 91.7% specificity in the detection of CRV.[23] We had 12 patients having CRV found introperatively, but only two patients had pre-operative CT urography reporting CRV. It may be due to improper acquisition of angiographic phase by CT urography protocol adopted at our institute (Triple bolus, single phase). In all but one patient, transposition of renal pelvis after dismembering it from ureter was done. In one patient, hitching of vessel was done.

The mean operative time was 140 min with a range of 75–240 min. Initial few cases had prolonged operative time. Very soon, we got accustomed to efficiently use this most advanced surgical armamentarium. That is why, it is told that robotic surgery has short learning curve as compared to laparoscopy. Towards the end of 30th case, in uncomplicated and straight forward cases of pyeloplasty, we have console time (dissection + anastomosis time) in the range of 75–90 min which is comparable to most large series at high-volume centres. The docking time also substantially reduced as compared to at the beginning. The mean blood loss was 60 ml and the mean hospital stay was 3.5 days (range: 2–12) which is comparable to other studies. Post-operative outcome was similar to other reported case series. We had success rate of 93% in terms of resolution of symptoms and relief of obstruction at a mean follow-up of 10.9 months.[132425]

Biopsy of excised PUJ showed fibromuscular tissue in nine patients and fibrosis in one patient. Twenty patients showed no abnormality. Of these nine patients with fibromuscular dysplasia, three patients also had crossing vessels. Richstone et al. found no histological abnormality in 43% of patients with crossing vessel (P < 0.0003), and in patients without CRV, only 10% were found to have absence of any intrinsic abnormality.[26]

CONCLUSION

Robotic pyeloplasty is safe, effective procedure even in the hands of beginner. Its results and outcome are encouraging. It should be the first choice for the management of primary as well as secondary PUJO at the centre availing the facility of robot. It is also very effective in the management of complex PUJO.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.