Management for Ureteral Stenosis: A Comparison of Robot-Assisted Laparoscopic Ureteroureterostomy and Conventional Laparoscopic Ureteroureterostomy

Abstract

Background:

To describe and analyze our experience of robotic-assisted laparoscopic ureteroureterostomy (RALU) and conventional LU for the repair of ureteral stenosis and compare the differences of safety and efficacy between RALU and LU.

Materials and Methods:

Patients who underwent RALU or LU for ureteral stenosis were retrospectively analyzed. Baseline characteristics, details of stenosis, surgery and some laboratory tests, and follow-up data were collected and analyzed.

Results:

Among 126 patients presented with ureteral stenosis, 65 patients underwent RALU and 61 patients underwent LU. All operations were completed successfully without conversion to open surgery. Both groups were comparable in baseline characteristics and details of stenosis. The mean operative time, suturing time, and hospitalization time of patients in RALU group were significantly less than those in LU group. The mean operative time of the RALU group was 126.34 minutes, whereas the mean operative time of the LU group was 176.57 minutes (P < .001). The average suturing time of RALU and LU was 26.88 and 70.43 minutes, respectively (P < .001). The mean hospitalization time of RALU and LU was 4.01 and 5.02, respectively (P < .001). RALU presented a lower degree of leukocytes rise than LU (P < .001). The mean follow-up time was 29.52 months.

Conclusions:

RALU and LU both are safe and feasible for ureteral stenosis with a low incidence of complications. Compared with LU, RALU may be a better choice with shorter operative time, suturing time, postoperative hospitalization time, and slighter inflammation. Further clinical studies of high quality are needed to confirm the priority of RALU.

Introduction

Ureteral stenosis is a disease that can occur in both children and adults. It may result from several causes including malignancy, ureteral calculus, radiation, ischemia, or trauma caused by surgical dissection, periureteral fibrosis caused by abdominal aortic aneurysm, or endometriosis, endoscopic instrumentation, renal ablation injury, infection (tuberculosis), and idiopathic condition.

Treatment for ureteral stenosis ranges from endourologic options, including ureteral stent placement, balloon dilation, and endoureterotomy to surgical repair. Surgical strategy including ureteroureterostomy, ureteroneocystostomy, psoas hitch, boari flap, and renal descensus is performed based on ureteral defect length.

Ureteroureterostomy, also known as ureteral–ureteral anastomosis, is a classic treatment option that the segments of ureter are reconnected after excision of a stenosis.¹ At first, open ureteroureterostomy (OU) was performed, but it usually resulted in long hospitalization time and more blood loss. Nezhat et al.² first reported laparoscopic management of an obstructed ureter resulting from endometriosis. After that, Piaggio and Gonzalez³ and Smith et al.⁴ reported laparoscopic ureteroureterostomy (LU) in the pediatric population. More recently, Mufarrij et al.,⁵ Thiel et al.,⁶ Passerotti et al.,⁷ Lee et al.,⁸ and Lee et al.⁹ applied robotic-assisted LU (RALU) to a small number of patients. These studies proved the feasibility and safety of minimally invasive ureteroureterostomy. However, few studies have compared the robotic-assisted laparoscopic and conventional laparoscopic approach for ureteroureterostomy.

In this study, we review our experience of RALU and LU for the repair of ureteral stenosis and compare the differences of safety and efficacy between RALU and LU.

Materials and Methods

Patients selection

We retrospectively selected same number of patients undergoing RALU or LU for ureteral stenosis in our department from January 2014, a year before our hospital was equipped with an operating robot, Intuitive Surgical DaVinci S/Si system^®, to December 2018. Patients with different etiologies and location in the ureter were included, but patients who experienced ureteral reimplantation were excluded. No patients were converted to open surgery. Our study follows the principles of the Declaration of Helsinki. Decision for an RALU or LU was based on the surgical referral pattern to our urology department rather than patient selection criteria.

Surgical technique

All patients underwent computed tomography or ultrasonography to confirm and assess the location and the extent of the stenosis before surgery. Several tests including basic blood test and kidney function test were conducted before surgery.

The RALU and LU were carried out by 2 urologists who had both performed more than a 1000 laparoscopic surgeries. All surgeries were performed by the transperitoneal approach. The patient was placed in the oblique supine position and pneumoperitoneum was achieved. Four trocars including one 12 mm optic trocar, two for working arms, and one 12 mm conventional laparoscopic trocar were prepared for RALU. Three trocars were prepared for LU. The monopolar electrotome and bipolar electrotome were used in RALU, whereas the ultrasonic scalpel was used in LU. After meticulous dissection of dense adhesions, ureteral stenosis was exposed, identified, and freed up. To avoid torsion, a guide suture was used to orient the anterior borders of the proximal and distal margins. The ureteral lesion is then resected.

A tension-free interrupted or continuous anastomosis was performed 4-0 monocryl while preserving ureteral vascularization. A Double-J stent was placed into the ureter, a drainage tube was placed at the anastomosis, and a Foley catheter was used for catheterization.

Blood test was performed immediately after the surgery and kidney function was also monitored. About 2 and 5 days after the operation, the drainage tube and Foley catheter were removed, respectively. The Double-J stent was left in place for at least 4 weeks and then removed.

Data extraction

Baseline characteristics including gender, age, and body mass index (BMI) were collected. We also collected patients' stenosis details, including laterality, site, and etiology. Information about surgery including operative time and suturing time, details of blood test and kidney function, and follow-up data were collected.

Statistical analysis

Statistical analysis was performed by SPSS^® 23.0. Categorical variables were presented using absolute numbers and percentage. Continuous variables are presented as mean and standard deviation, whereas median and range of some were also presented. In the comparison part, the chi-square test was used for categorical variables and t-test was used for continuous variables. For all statistical tests, two-tailed P values <0.05 were considered statistically significant.

Results

In total, 126 patients undergoing end-to-end ureteral–ureteral anastomosis were included. Among these patients, 65 were performed with RALU, and 61 were managed with conventional LU. All operations were completed successfully without conversion to open surgery.

The baseline characteristics, stenosis and surgery details, and follow-up information of patients are summarized in Table 1. In 74 patients, stenosis was localized in the right ureter and 52 patients in the left ureter. In terms of site, more than half (65 patients) of stenoses were localized in the upper ureter, with 31 cases in the middle ureter, and 30 cases in the lower ureter. Ureteral stenosis was due to different causes. Among iatrogenic causes, 62 patients experienced ureteroscopy with lithotripsy (URS), 27 patients with ureterolithotomy, 13 with abdominal surgery, 8 patients with endometriosis, 5 patients with tuberculosis, 3 patients with radiation, 2 patients with idiopathic condition, and 6 patients with other causes. In the present series, the mean operative time and suturing time were 150.66 and 47.96 minutes, respectively. The average postoperative hospitalization time was 4.50 days, ranging from 3 to 9 days.

Table 1.

Basic Characteristics, Stenosis, and Surgery Details, Follow-Up Information of Patients

Variables	Value
Gender, n (%)
Male	83 (65.9)
Female	43 (34.1)
Age (years)
Mean ± SD	46.01 ± 12.37
Median (range)	45 (19–72)
BMI (kg/m²)
Mean ± SD	22.49 ± 3.07
Median (range)	22.49 (16.73–29.75)
Laterality of the stenosis, n (%)
Right	74 (58.7)
Left	52 (41.3)
Site of the stenosis, n (%)
Upper	65 (51.6)
Middle	31 (24.6)
Lower	30 (23.8)
With stones or not, n (%)
Yes	28 (22.2)
No	98 (77.8)
Etiology, n (%)
After URS	62 (49.2)
After ureterolithotomy	27 (21.4)
After abdominal surgery	13 (10.3)
Endometriosis	8 (6.3)
Tuberculosis	5 (4.0)
Radiation	3 (2.4)
Idiopathic condition	2 (1.6)
Other	6 (4.8)
Surgical approach, n (%)
RALU	65 (51.6)
LU	61 (48.4)
Operative time (hours)
Mean ± SD	150.66 ± 47.34
Median (range)	140.5 (87–260)
Suturing time (minutes)
Mean ± SD	47.96 ± 22.78
Median (range)	34.00 (20–89)
Postoperative hospitalization time (days)
Mean ± SD	4.50 ± 1.39
Median (range)	4 (3–9)
Follow-up time (months)
Mean ± SD	29.52 ± 9.77
Median (range)	26 (16–56)
Clavien complications, n (%)
Grade 1	7 (5.6)

BMI, body mass index; LU, laparoscopic ureteroureterostomy; RALU, robotic-assisted LU; SD, standard deviation; URS, ureterorenoscopy with lithotripsy.

Table 2 compares the basic characteristics and stenosis details between the RALU group and LU group. Two groups were comparable in baseline characteristics, including gender, age, BMI, and laterality. The mean age of patients in the RALU group was 46.29 years old, ranging from 22 to 72 years old, and in the LU group, it was 45.70 years old, ranging from 19 to 69 years old. Sixteen (24.6%) patients in the RALU group were overweight with BMI >24 kg/m², and 19 (31.1%) patients in LU group were overweight. Both groups were also comparable for stenosis details, including laterality, site, causes of stenosis, and whether accompanied with stones. The major laterality, site, and cause of two groups were all “right side,” “upper ureter,” and “after URS,” respectively. Only a small fraction of patients were accompanied with stones in both groups.

Table 2.

Comparison of Baseline Characteristics and Stenosis Details Between RALU Group and LU Group

	RALU (n = 65)	LU (n = 61)	P
Gender, n (%)
Male	40 (61.5)	43 (70.5)	.289
Female	25 (38.5)	18 (29.5)
Age (years)
Mean ± SD	46.29 ± 12.66	45.70 ± 12.15	.791
Median (range)	44 (22–72)	46 (19–69)
BMI (kg/m²)
Mean ± SD	22.09 ± 3.24	22.91 ± 2.85	.138
Median (range)	22.41 (16.73–29.75)	22.86 (18.47–28.37)
Laterality of the stenosis, n (%)
Right	37 (56.9)	37 (60.7)	.671
Left	28 (43.1)	24 (39.3)
Site of the stenosis, n (%)
Upper	34 (52.3)	31 (50.8)	.804
Middle	17 (26.2)	14 (23.0)
Lower	14 (21.5)	16 (26.2)
With stones or not, n (%)
Yes	17 (26.2)	11 (18.0)	.273
No	48 (73.8)	50 (82.0)
Etiology, n (%)
After URS	30 (46.2)	32 (52.5)	.803
After ureterolithotomy	13 (20.0)	14 (23.0)
After abdominal surgery	8 (12.3)	5 (8.2)
Endometriosis	3 (4.6)	5 (8.2)
Tuberculosis	3 (4.6)	2 (3.3)
Radiation	2 (3.1)	1 (1.6)
Idiopathic condition	1 (1.5)	1 (1.6)
Other	5 (7.7)	1 (1.6)

BMI, body mass index; LU, laparoscopic ureteroureterostomy; RALU, robotic-assisted LU; SD, standard deviation; URS, ureterorenoscopy with lithotripsy.

Table 3 gives the comparison of surgery details and follow-up data between two groups. The average operative time, suturing time, and postoperative hospitalization time of patients in the RALU group were significantly less than those in the LU group. In the RALU group, operative time of 53 (81.5%) patients was <150 minutes, and that of only 5 (7.7%) patients was >180 minutes. However, in the LU group, the operative time of only 14 (22.6%) patients was <150 minutes and operative time of 28 (45.9%) patients was >180 minutes. In the RALU group, the suturing time of 57 (87.7%) patients was ≤30 minutes, and the suturing time of no patient was >40 minutes. However, in the LU group, the suturing time of all patients was >45 minutes, with a maximum of 89 minutes.

Table 3.

Comparison of Surgery Details and Follow-Up Data Between RALU Group and LU Group

	RALU (n = 65)	LU (n = 61)	P
Operative time (hours)
Mean ± SD	126.34 ± 32.15	176.57 ± 47.37	<.001
Median (range)	126 (87–230)	177 (90–260)
Suturing time (minutes)
Mean ± SD	26.88 ± 3.85	70.43 ± 8.43	<.001
Median (range)	27 (20–38)	71 (45–89)
Hemoglobin decline (g/L)
Mean ± SD	14.43 ± 10.93	12.74 ± 11.36	.396
Leukocytes rise (10⁹/L)
Mean ± SD	3.26 ± 2.28	5.07 ± 1.52	<.001
Creatinine decline (μM)
Mean ± SD	6.43 ± 22.47	7.49 ± 10.77	.734
GFR rise (mL/minutes)
Mean ± SD	1.45 ± 7.34	1.46 ± 7.56	.995
Postoperative hospitalization time (days)
Mean ± SD	4.01 ± 1.07	5.02 ± 1.51	<.001
Median (range)	4 (3–6)	5 (3–9)
Follow-up time (months)
Mean ± SD	27.31 ± 9.48	31.89 ± 9.61	.008
Median (range)	23 (16–46)	28 (22–56)
Clavien complications, n (%)
Grade 1	3 (4.6)	4 (6.6)	.634

GFR, glomerular filtration rate; LU, laparoscopic ureteroureterostomy; RALU, robotic-assisted LU; SD, standard deviation.

In terms of postoperative hospitalization time, the mean of the LU group is longer than that of the RALU group by ∼1 day. Prolonged hospitalization time was mainly due to postoperative pain, prolonged fever, and wound infection. In the laboratory tests, the number of leukocytes in the LU group experienced a significantly higher rise than those in the RALU group. The difference of follow-up time between the two groups was significant. The overall average follow-up time was 29.52 months. The mean follow-up time of the RALU group was 27.31 months, ranged from 16 to 46 months, and that of the LU group was 31.89 months, ranged from 22 to 56 months.

We evaluated the number, type, and grade of postoperative complications according to the Clavien–Dindo Classification. In the RALU group, 2 patients had fever after operation, with body temperature of up to 39.2 and 39.6°C, respectively, and 1 patient had a wound infection. In the LU group, 3 patients had fever up to 38.9, 39.2, and 39.4°C, respectively, and 1 patient had a wound infection. They all were treated by medical therapy.

Discussion

Ureteral stenosis is a relatively common disease in urology department resulting from various causes. Proper treatment of a ureteral stenosis is essential to preserve renal function. There are several therapy approaches, among which surgery is a conventional therapy. Before any surgical repair, it is essential to conduct careful evaluation of the nature, location, and length of the ureteral stenosis, because they heavily influence the surgery options. Ureteroureterostomy is a surgery that is most appropriate for the short defect involving the upper ureter or mid ureter, either in the form of stenosis or as a consequence of recent injury. Now RALU or LU is often performed rather than OU.

In 1992, Nezhat first reported LU management of an obstructed ureter.² In that case, ureteroureterostomy was performed laparoscopically over a ureteral stent after resection of the obstructed ureteral site.² After that, many case reports or series came out. Compared with OU, LU is a minimally invasive surgical way with a shorter hospitalization time, faster recovery, and similar outcome. Although LU becomes an ideal alternative to OU,^3,4 its drawback is also obvious. The difficulty in intracorporeal suturing and limited movement of instruments make it hard for urologists to master this modality.¹⁰ Several studies concluded that a skilled laparoscopic urologist is required for successful LU.^11,12

In recent decades, the introduction of robotic platform makes laparoscopic surgery easier dramatically. In 2006, Yee first reported RALU in an adolescent with an obstructed upper pole system and crossed renal ectopia with fusion.¹³ In 2007, Mufarrij pointed out that robotics can be successfully and safely used for virtually any type of upper urinary tract reconstruction.⁵ In 2008, Passerotti confirmed that RALU is a reliable and efficient technique for the correction of ureteral obstruction in children.⁷ In 2015, Lee concluded that RALU was a safe and effective alternative to OU in children with duplication anomalies and single system obstructed ureters.⁹ Now RALU is generally accepted by doctors all over the world.

However, so far, there were few studies focused on the comparison between robotic and laparoscopic approaches of ureteroureterostomy. In 2016, Schiavina reported that both robotic and pure laparoscopic approaches may offer good results in terms of perioperative outcomes, low incidence of complications, and recurrence, but the robotic approach may present less estimated blood loss and hospitalization time than the laparoscopic approach.¹⁴

In our study, we selected 126 patients with comparable baseline characteristics for RALU or LU and compared their safety and efficiency. Compared with laparoscopic approach, robot-assisted laparoscopic approach significantly shortened the operative time and suturing time. This is a proof that the robotic system could provide finer operation, larger operative view, and eliminate unnecessary tremor. We also found that LU might lead to a significantly larger increase in leukocytes after surgery than RALU, which indicated that LU was associated with a more severe inflammation or stress response. In another study, the average intraoperative blood loss of RALU (47.2 mL) was less than that of LU (91.2 mL).¹⁴

We concluded that both approaches had almost the same hemoglobin decline of ∼14 g/L, but no patients needed blood transfusion. The decrease in hemoglobin might be caused by intraoperative intravenous infusion. After surgery, serum creatinine slightly declined and the glomerular filtration rate slightly increased, but there was no significant difference between the two groups. This indicated that both approaches could remove stenosis successfully to the same extent.

Among follow-up data, the postoperative hospitalization time of RALU was significantly less than that of the LU group. The prolonged hospitalization time was mainly due to obvious postoperative pain. All surgeries were performed successfully, and they reported only 7 (5.6%) grade 1 complications according to the Clavien system, which indicated a high safety of RALU and LU. The follow-up time of the RALU group was significantly shorter than that of the LU group. This was affected by the equipment time of the robotic system.

Our study is the largest series considering robotic-assisted laparoscopic and laparoscopic surgery for ureteral stenosis, but it has several limitations. Its retrospective design, short follow-up time, and limited cases weakened the statistical significance of some differences between the two groups. In addition, the experience between 2 urologists might be different, although they were both experienced and professional. Besides, our hospital is among the top in China. Patients in other hospitals might be transferred to our hospital, but we seldom transfer patients to those hospitals. This may limit the generalizability of our results.

Conclusions

RALU and LU both are safe and feasible for the repair of ureteral stenosis with a low incidence of complications. Compared with LU, RALU may be a better choice because of its shorter operative time, suturing time, postoperative hospitalization time, and slighter inflammation.

Footnotes

Acknowledgment

We deeply thank Zhangqun Ye for his guidance.

Ethical Approval

For this type of study, formal consent was not required.

Disclosure Statement

No competing financial interests exist.

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