Percutaneous nephrolithotomy or flexible ureteral lithotripsy, which one is better for patients with upper ureteral calculi of 1.5-2.0cm in diameter

doi:10.21203/rs.3.rs-3107480/v1

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Research Article

Percutaneous nephrolithotomy or flexible ureteral lithotripsy, which one is better for patients with upper ureteral calculi of 1.5-2.0cm in diameter

https://doi.org/10.21203/rs.3.rs-3107480/v1

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Purpose

To evaluate the clinical efficacy and safety of flexible ureteral lithotripsy (FURSL) and percutaneous nephrolithotomy (PCNL) in the treatment of upper ureteral impacted calculi (1.5cm to 2.0cm in diameter).

Methods

From December 2018 to October 2022, 104 patients with calculi in the upper ureter received percutaneous nephrolithotomy (PCNL)or flexible ureteroscopic lithotripsy (FURSL) in our institution. The clinical data of the patients in the two groups were retrospectively searched. Stone removal rate, operation time, blood loss, postoperative pain score, postoperative inflammatory factor, postoperative complication rates were compared between the two groups.

Results

A total of 104 patients were included in the study. The stone clearance rate and the secondary surgery rate were 88.89% and 7.41% in the FURSL group, the figures were 97.96% and 2.0% in the PCNL group (p=0.067, 0.198).Compared to patients in FURSL group, patients in the PCNL group had shorter operation time(PCNL 71.81±18.94minutes vs FURSL 86.80±22.49minutes, p=0.0004), fewer complications(PCNL 20.37% vs FURSL 6.12%), and lower postoperative inflammatory factor（p=0.0004）, yet they got more hemoglobin drop（PCNL 13.14±9.81g/L vs FURSL 4.77±3.55g/L, p<0.0001）, higher postoperative pain scores (p=0.0017) in the first three postoperative days.

Conclusion

Both FURSL and PCNL were effective methods for treating upper ureteral stones of 1.5-2.0cm in diameter given that there was an extremely high stone clearance rate and a very low secondary surgery rate. While PCNL effectively reduced operative time, postoperative inflammatory factor and the risk of postoperative complications, it had more hemoglobin drop and postoperative pain scores comparing with FURSL.

percutaneous nephrolithotomy

flexible ureteral lithotripsy

upper ureteral stone

Urological stones are one of the most common urological disorders in clinical practice for urologists. It reported 1–20% people suffer from urological stones during their lifetime [1, 2]and incidence rate is increasingly rising around the world[3, 4]. The ureteral stones are more severe and often occurred in the upper ureter, as they lead to hydronephrosis and renal impairment[5–7].

To be precise, these upper ureteral stones, usually combining with some degree of hydronephrosis on the affected side are located in the ureter and remain in the same position for days or even weeks and could lead to unilateral renal impairment and severe loss of unilateral renal function. Also, multiple polyp formation below and dilated and tortuous ureters above are associated, which make the treatment harder[8, 9].

In clinical practice, patients could not be cured when only receiving non-operation treatment. Some other surgeries have also been unpopular because of a variety of issues[10, 11]. For example, ureteral rigidoscopy is a complicated procedure for the treatment of stones in the upper ureter and has a low success rate as the stones tend to travel up to the renal pelvis during the surgery. Another option, laparoscopic surgery is indicated for complex and large stones and has been gradually replaced in recent years due to the high degree of trauma and slow postoperative recovery[12–14].Also, extracorporeal shock wave lithotripsy is suitable for patients with upper ureteral stones, the postoperative residual fragments limit its acceptance among patients[15, 16].

With the development of minimally invasive urological techniques, the most common and widely-accepted options for upper ureteral calculi are percutaneous nephrolithotripsy (PCNL) and retrograde intrarenal surgery, which is flexible ureteral lithotripsy (FUSRL) in this case. When the kidney stone is greater than 2.0 cm in diameter, PCNL is recommended and widely accepted by experts.

However, in newest consensus on PCNL[17], which were made by hundreds of experts from Europe and Asia, PCNL is recommended when stones are greater than 1.5 cm in diameter in the upper ureter. While retrograde intrarenal surgery, mainly shown as flexible ureteroscopy lithotripsy (FURSL) is recommended for stones that are smaller than 2.0cm in diameter in another new consensus by similar experts[18]. Consequently, there is no consensus when the upper ureteral stone is between 1.5cm to 2.0 cm in diameter.

Thus, we conducted this retrospective study to evaluate the clinical outcomes of PCNL versus FURSL in the treatment of upper ureteral stones by searching and analyzing the clinical data from patients through imaging system in our hospital. To our knowledge, this is the first study regarding upper ureteral stone with a diameter of 1.5cm to 2.0cm.

2.1 Research ethics board approval

This study was approved by the ethics committee of Shanghai Jinshan District Central Hospital (Number: JSYY2023201). All methods were performed in accordance with the Declaration of Helsinki. Informed consent was obtained from all subjects and/or their legal guardians.

2.2 Clinical information

All the patients were retrospectively selected from our institution: Shanghai Jinshan District Central Hospital. The diameter of ureteral stones was measured from coronal, cross-sectional and sagittal CT images, the longest diameter was recorded as the selection basis. patients with upper ureteral stones with a diameter of 1.5cm to 2.0cm who were treated by PCNL or FURSL from December 2018 to October 2022, were selected through the imaging system in our institution.

2.3.1 Inclusion criteria: (1) the stone was in the upper ureter and located there more than 2 months; (2) clinical data were kept intact; (3) the operators were part of the same surgical team.

2.3.2 Exclusion criteria: (1) patients with severe infections such as septic kidney; (2) patients with urological tumors; (3) patients with psychiatric disorders and impaired consciousness; (4) patients with cardiac, pulmonary, hepatic and renal insufficiency; (5) patients with coagulation disorders; (6) patient with cardiovascular and cerebrovascular diseases; (7) with spinal deformities.

2.4 Treatment Procedure for PCNL and FURSL

2.4.1 Surgical Procedure for PCNL group:

After receiving general anesthesia with supine lithotomy, patients were inserted with the F6 ureteral catheter through the F12 nephroscope(Richard_Wolf)in their upper ureter. Then patients were later changed to the prone position. Subsequently, the patient's renal area and ureter were scanned to the locate the stone distribution in the ultrasound image using a Danish BK ultrasound detector. Next, a 16G puncture needle (Cook Medical) was passed through the posterior superior calyx or posterior middle calyx of the kidney in the area between the subcostal or subcostal 12 and the mid-axillary line to the scapular line under ultrasound guidance. Through the urine drainage path, the guidewire (Cook Medical) was placed into the collecting system and the percutaneous tract was formed with a 0.8 cm incision and a fascial dilator dilated from F8 to F18. After this, a holmium laser lithotripter (Lumenis) was attached close to the stone which was subsequently crushed and flushed out of the body with saline.

2.4.2: Surgical Procedure for FURSL group

FURSL group: patients received general anesthesia and were placed in the lithotomy position. An F7.8 ureteroscope (Karl Storz) was inserted through the urethra under direct vision, if there was a double J tube, it should be removed at first. It was followed by the progress that the rigid ureteroscope was removed, the flexible ureteroscope sheath (F12/14, Cook Medical) was inserted through the smooth guide wire and the flexible ureteroscope (F7.8, Karl Storz) was inserted through the sheath. Next, the stone was transferred to the middle or upper calyx of the kidney with a reticular basket and subsequently crushed with holmium laser (Lumenis). Finally, it was removed out of body with a reticular basket or saline and a double J tube was left in place after the procedure.

After the surgery (PCNL or FURSL), the patient receives antibiotics, and if there was an infection, the patient continued to receive sensitive antibiotics for about 3 days according to the urine culture results, and the blood tests are repeated within 3 days after the surgery. Two weeks after surgery, the patient receiving CT scan detecting residual stones and a removal of the double J-tube, and if there were residual stones, they would get a second operation one month after the surgery.

2.5 Observation Index

The following data were collected: Operation time; intraoperative bleeding, measured with hemoglobin drop; stone clearance rate, measured with CT images before and one month after surgery; Complication (including high fever, greater than 39℃, ureteral stricture, etc.); secondary surgery rate; Postoperative VAS score (day1 to day3); postoperative inflammatory factor indicators (C-reactive protein, day1 to day3).

2.6 Statistical methods

Data analysis was performed using GraphPad Prism 9 for Windows. Categorical data were examined using the Chi-square test and the continuous variable was assessed using the independent sample t-test. p < 0.05 was considered to indicate a statistically significant difference, and the measurement data of normal distribution were represented by (x ± s) and data were compared using a t-test. Also, data were expressed as percentages (%) or the number of cases.

3.1 Clinical data comparison between PCNL and FURSL group

A total of 103 patients with upper ureteral stones with a diameter of 1.5cm to 2.0cm were included and analyzed in this study. In FURSL group, there were 34 males and 21 females, age ranging from 28 to 77(mean age :55.02 ± 13.43), and in the PCNL group, there were 30 males and 19 females, aged 31 to 74 years (mean age :53.12 ± 9.64), The differences in gender, age, stone diameter, stone density, and hydronephrosis between the two groups were not statistically significant (Table 1).

3.2 Comparison of Perioperative and Postoperative-Related Indexes

PCNL group showed a better performance in operation time and complications (71.81 ± 18.94 minutes vs 86.80 ± 22.49 minutes, p = 0.0004; 11 cases (20.37%) vs 3 cases (6.12%)). FURSL group had a lower Hemoglobin drop (4.77 ± 3.55g/L vs 13.14 ± 9.81g/L, p < 0.0001). The complications were high fever and postoperative bleeding. Eight patients had postoperative high fever in FURSL group while only 2 patients had this in PCNL group. However, one patient in PCNL group had uncontrollable postoperative bleeding and ultimately underwent highly selective embolization. (Table 2)

The rate of stone clearance and secondary surgery rate between the FURSL group and PCNL group were 88.89% versus 97.96% (p = 0.067) and 7.41% versus 2.00%(p = 0.198). 4 patients in FURSL group received a second surgery to remove the residual stone and the other 2 expulsed stone without a surgery. While in PCNL group, only one patient received super selective renal artery embolization, other patients with residual stone did not need a surgery.

3.3 Comparison of postoperative pain scores between the two groups in the first three postoperative days.

The postoperative pain scores was postoperatively lower in the FURSL group compared to PCNL group (p = 0.0017).The scores in FURSL group for the first three postoperative days were 2.46 ± 0.61,1.79 ± 0.54, and 1.30 ± 0.42 respectively and the figures in PCNL group were 3.15 ± 0.68,2.54 ± 0.61, and 1.95 ± 0.58. (Firgure1)

Firgure1.Comparison of postoperative VAS pain scores in the first three postoperative days.

3.4 Comparison of postoperative inflammatory factor indicators between the two groups in the first three postoperative days

The C-reactive protein gradually decreased significantly in both groups from the 1st to 3rd day postoperative period, while the C-reactive protein higher in FURSL than in PCNL (p = 0.0004). (Table 3)

In this retrospective study, 103 patients showed that PCNL and FURSL were both effective methods treating upper ureteral stones of 1.5-2.0 cm in diameter. Patients could get rid of upper ureteral stones after receiving these 2 surgeries, the stone clearance rates were extremely quite high, 88.89% and 97.96%, respectively. only 7.41%(FURSL) and 2%(PCNL) patients need a second surgery. Furthermore, patients treated with PCNL had higher hemoglobin drop compared to those receiving FURSL, however, they had a shorter operation time and fewer complications. 8 patients had postoperative high fever in FURSL group and 2 had high fever in PCNL group. After 1 to 3 days of antibiotic treatment, all these patients had their temperature under control. Also, the postoperative inflammatory factors also showed that PCNL could avoid a possible infection compared to FURSL.

This study first focused on the upper ureteral stones of 1.5-2.0 cm in diameter although there were plenty of research regarding the treatment of ureteral stones with PCNL or FURSL, as both these 2 surgeries were the most wide-accepted surgeries currently. According to the previous studies, the risk of complications associated with percutaneous nephrolithoscopy, such as bleeding, related to its access diameter [13–15]. In this study, we used 16-22F sheath, and it was proved that postoperative complications are greatly declined compared to the standard percutaneous nephrolithoscopy[16]. However, the postoperative bleeding issue could not be avoided and highly selective embolization was effective remedy for this problem. In our study, only one patient had postoperative bleeding and received highly selective embolization finally. On the other hand, PCNL is the treatment of choice for large renal stone, especially for staghorn stones. According to the up-to-date consensus on PCNL[11], it is recommended for the stones are greater than 1.5 cm in diameter in the upper ureter.

Meanwhile, ureteral lithotripsy is a procedure that involves the placement of a flexible ureteroscope through the body's natural lumen, combined with a laser to treat renal or ureteral stones safely and effectively[19, 20]. Ureteral lithotripsy can be adjusted to reach various locations of the renal calyces and effectively remove stones in different locations.Yet it can promote intrarenal pressure results from outflow obstructed by small fragments, as a result, it could increase the risk of infections or even sepsis[21]. Consequently, for these upper ureteral stones, they are pushed into the calyces during surgery at first and then lithotripsy is performed by laser to avoid excessive pressure and damage to the ureter which can cause ureteral stenosis[22].

In our study, the upper ureteral calculi could be displaced to the upper or middle calyces with a mesh basket and then lithotripsy was performed with good results. Another newest consensus on retrograde intrarenal surgery gave a recommendation that a stone less than 20 mm in diameter is the best indication for retrograde intrarenal surgery.Thus, for those 1.5 to 2.0 cm stones in diameter, experts did not give a decisive conclusion according to the newest recommendation. In addition to the expert consensus, we found a few studies comparing PCNL and RIRS for renal or ureteral stones less than 2.0 cm in diameter[23–25]. However, there are no studies that specifically focus on upper ureteral stones of 1.5-2.0 cm in diameter, which means that there is no evidence to prove which procedure is better for stones of this size.

This study was a retrospective study, and therefore potential selection bias could not be avoided. In addition, the sample size of this study was insufficient and some clinical data were not recorded to draw conclusive conclusions. Therefore, further multicenter randomized controlled trials and randomized controlled trials with larger sample sizes are needed to complement our study.

In this unprecedent study, it was indicated that both FURSL and PCNL are effective methods for treating upper ureteral stones with a diameter of 1.5- 2.0 cm. Also, FURSL can effectively reduce surgical bleeding, postoperative pain, while PCNL can reduce operation time, the risk of infection and complications. Therefore, doctors could select suitable surgical treatment for those patients depending their different clinical situation.

PCNL: percutaneous nephrolithotripsy; FUSRL: flexible ureteral lithotripsy; VAS: Visual Analog Scale

-Ethics approval and consent to participate

-Consent for publication

Not applicable.

-Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

-Competing interests

The authors declare that they have no competing interests.

-Funding

Not applicable.

-Authors' contributions

Study concept: Hengda Hu, Wenpu Chen and Guofeng Yu;Data collection or management and data analysis: Wenpu Chen and Guofeng Yu. Study design and drafting of the manuscript: Hengda Hu. Revision of the manuscript: Wenpu Chen and Guofeng Yu.

-Acknowledgements

Not applicable.

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Table 1

Clinical data comparison between FURSL and PCNL group.
	FURSL (n = 55)	PCNL (n = 49)	P value
Age(Y)	51.02 ± 10.86	48.26 ± 11.22	0.211
Gender(Male/Female)	34/21	30/19	0.839
CT value	900.64 ± 180.16	864.52 ± 200.83	0.336
Diameter(cm)	1.65 ± 0.31	1.69 ± 0.22	0.376
hydronephrosis	55	49	1

Table 2

Comparison of Perioperative and Postoperative -Related Indexes.
	FURSL	PCNL	P value
Operation time, (min)	86.80 ± 22.49	71.81 ± 18.94	0.0004
Hemoglobin drop (g/L)	4.77 ± 3.55	13.14 ± 9.81	< 0.0001
stone clearance rate	48(88.89%)	48/49(97.96%)	0.067
Complication	11(20.37%)	3(6.12%)	0.035
Secondary surgery rate	4/54(7.41%)	1/49(2.00%)	0.198

Table 3

Comparison of postoperative inflammatory factor between the two groups
	C-reactive protein(mg/L)
Postoperative Day	1	2	3
FURSL	8.97 ± 1.35	7.93 ± 1.20	6.80 ± 1.14
PCNL	7.32 ± 1.10	6.41 ± 1.03	5.27 ± 1.09

No competing interests reported.

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You are reading this latest preprint version

Percutaneous nephrolithotomy or flexible ureteral lithotripsy, which one is better for patients with upper ureteral calculi of 1.5-2.0cm in diameter

Status:

Version 1

Abstract

Figures

1. Introduction

2. Patients and method

2.1 Research ethics board approval

2.2 Clinical information

2.4 Treatment Procedure for PCNL and FURSL

2.4.1 Surgical Procedure for PCNL group:

2.4.2: Surgical Procedure for FURSL group

2.5 Observation Index

2.6 Statistical methods

3. Results

3.1 Clinical data comparison between PCNL and FURSL group

3.2 Comparison of Perioperative and Postoperative-Related Indexes

3.3 Comparison of postoperative pain scores between the two groups in the first three postoperative days.

3.4 Comparison of postoperative inflammatory factor indicators between the two groups in the first three postoperative days

4. Discussion

5. Conclusion

6. Abbreviations

7. Declarations

References

Tables

Additional Declarations

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