Do Anesthesia Methods in Retrograde Intrarenal Surgery Make Difference Regarding the Success of Ureteral Access and Surgical Outcomes?

Abstract

Background:

Retrograde intrarenal surgery (RIRS) is a safe and minimally invasive method for the endoscopic treatment of upper urinary system stones especially sized <2 cm. Ureteral entrance is an important stage of RIRS. General anesthesia (GA) is usually used for RIRS. There is not enough data about the effect of anesthesia methods on the success of ureteral entrance and RIRS. We aimed to evaluate the effects of anesthesia methods (spinal anesthesia [SA], epidural anesthesia [EA], and GA) on the ureteral access and RIRS outcomes in primary surgery.

Methods:

After local ethical approval, 105 patients were prospectively randomized into three groups according to the anesthesia methods. GA, SA, and EA were defined as Group 1, 2, and 3, respectively.

Results:

Stone density was statistically significantly different between three groups (P = .008). Lithotripsy and operation time were significantly lower in Group 3 (P = .001). Dilatation and stone access time were significantly lower in Group 1. There was no statistically significant difference for scopy time, success, Visual Analog Scale score at 8th and 24th hours, and intraoperative and postoperative complications.

Conclusions:

GA may be recommended to decrease manipulations for the success of first ureteral access and time to reach the stone if there is not any contraindication.

Introduction

Retrograde intrarenal surgery (RIRS) is a safe and minimally invasive method for the endoscopic treatment of upper urinary system stones especially sized <2 cm. High comorbidity of percutaneous nephrolithotomy (PNL) and lower stone-free rate (SFR) of shock wave lithotripsy make RIRS an advantageous method.¹ Patient selection, correct usage of the surgical instruments and appropriate techniques increase safety and success. Ureteral access sheath (UAS) usage has made RIRS more popular.² The access into the ureter is an important stage of RIRS. The success of ureteral access and UAS placement depends on the axial force in the orifices and the friction coefficient on the surface of the UAS. The ability of the placement of ureteroscope through the UAS depends on the compression force.³ Enabling multiple access, decreasing intrarenal pressure, scope protection, minimizing ureteral injury, and making it easier to access collecting system are advantages of UAS.⁴ In primary surgeries, the first access may not be possible and increasing force can usually cause ureteral injury.⁵

There are studies about UAS insertion that mention increasing success rate of ureteral entrance and surgery. Some methods, increasing the ureteral entrance success such as ureteral balloon dilatation, passive dilatation by preoperative ureteral stenting, and preoperative alpha blocker usage were reported in these studies. These methods have pros and cons. Active balloon dilatation is an option but it has risks such as ureteral edema, postoperative discomfort, and seconder ureteral stricture.⁶ There are studies about the effect of stone and patient characteristics on the success of RIRS.^7,8 General anesthesia (GA) is usually used in RIRS. However, there is not enough data about the effect of anesthesia methods on the success of ureteral entrance and RIRS.

The anesthesia method may have a role in the success of ureteral entrance and RIRS by affecting manipulations at the ureteral entrance. In our study, we aimed to evaluate the effects of anesthesia methods (spinal anesthesia [SA], epidural anesthesia [EA], and GA) on the ureteral access and RIRS outcomes in primary surgery.

Methods

Patients

After local ethical approval, 105 patients, who had appealed to our clinic and underwent RIRS for the treatment of upper urinary system stones, were prospectively selected between February 2018 and January 2019. Patients were randomized into three groups according to the anesthesia methods. GA, SA, and EA were defined as Group 1, 2, and 3, respectively.

Primary patients >18 years old were included in our study. Patients who had neurogenic disease, urethral and/or ureteral stricture, access failure, kidney anomalies, contraindications for regional anesthesia (RA), ASA (The American Society of Anesthesiologists) ≥3, or who underwent preoperative ureteral stenting, chronic pain treatment, peroperative change of anesthesia methods were excluded. Also, we excluded the middle and distal ureteral stones because the distance from the stone to the orifice affects the stone access time directly, which could impair the standardization of the study.

All patients were evaluated with kidney ureter bladder graphy, urinary system ultrasonography, and noncontrast computed tomography (CT) preoperatively. Preoperative data such as age, gender, body mass index (BMI), stone density, stone size (the longest diameter in CT), preoperative creatinine levels, ASA score, stone laterality and localization, and comorbid diseases were recorded.

Prophylactic intravenous third generation cephalosphorin was administered to all patients 30 minutes before the operation. It was ensured that all urine cultures were sterile. In case of positive urine culture, the operation was performed after antibiotherapy. Informed consents were taken from all the patients before the operation. Informed consent was obtained from all individual participants included in the study. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Anesthesia method

Anesthesia was performed by the same anesthetist. Vascular access was performed to the patients with 20 G intravenous cannula in the surgery preparation room. Patients were monitored and systolic blood pressure, diastolic blood pressure, average blood pressure, pulse rate, and oxygen saturation (SpO₂) were measured noninvasively and recorded.

Group 1

The patients who were administered GA were monitored. Preoxygenation was performed with 100% oxygen for 3–5 minutes. Anesthesia induction was done with 2 μg/kg fentanyl, 2–3 mg/kg propofol, and 0.5 mg/kg rocuronium. After muscle relaxation, endotracheal intubation was performed. Controlled intubation was performed with 8–10 mL/kg tidal volume and 10–12/min respiration frequency settings. Anesthesia maintenance was performed with 1% MAC sevoflurane in 50% O₂ and 50% N₂O.

Group 2

In the SA group, preoperative hydration was performed with balanced electrolyte solution (500 mL) 30 minutes before the operation. After monetarization and skin cleaning, the anesthetist entered the vertebral space with midline approach technique from L3-L4 or L4-L5 in the sitting position. Twenty-five or 26 G spinal needle was used. After clear cerebrospinal fluid observing, 3 mL 0.5% hyperbaric bupivacaine (5 mg/mL) was administered slowly. Sensory block level was evaluated with the pinch method (Pinprick test). The operation was started after the sensory block level was in T6-T8 dermatome.

Group 3

In the EA group, after monetarization and skin cleaning, the anesthetist entered T11-T12 range with 18 G stiff needle in the sitting position. Epidural space was found with negative pressure method and an epidural catheter was placed. After 3 mL prilocaine HCl (Citanest^® 2% 20 mg) test dose medication, 1.5 mL prilocaine was added for each segment. The operation was started after the sensory block level was at T6 level.

RIRS technique

All operations were performed by 2 experienced surgeons. After anesthesia procedure, 0.038-inch hydrophilic guidewire was inserted into the ureter in modified dorsal lithotomy position during cystoscopy. Ureteral dilatation was performed with 9 Fr ureteroscope by following the guidewire. A 12/14 Fr UAS (Elite Flex, Ankara, Turkey) was placed into the ureter through a guidewire and 7.5 Fr flexible ureterorenoscope (Karl Storz^®, Flex-X², Germany) was advanced along UAS. After reaching to the stone, lithotripsy was performed with 200 μm holmium laser (Laser:Dornier; Meditech, Munich, Germany). Lithotripsy was performed at 8–15 Hz frequency and 1.2–3 J power. After complete fragmentation of the stones, the operation was ended. JJ stent was placed in all patients at the end of the operation. Time from starting endoscopy to accessing 1/3 distal ureter was defined as dilatation time. Time from UAS insertion into the ureter to access to the stone was defined as stone access time. The time between starting endoscopy and end of JJ stent insertion was defined as operation time. The time between starting and ending of lithotripsy was recorded as lithotripsy time. KUBG was performed for postoperative control of JJ stent and fragmented stones at the postoperative first day. Patients pain levels were evaluated with Visual Analog Scale (VAS) at 8th and 24th hours. JJ stent was taken 4 weeks later. Then, noncontrast CT was performed. Being stone free or having <3 mm residual fragment in intraoperative and postoperative controls (first day and first month) were described as successful.

Intraoperative and postoperative complications were recorded. Intraoperative complications were classified according to Satava classification system and postoperative complications were classified due to the modified Clavien classification system.^9,10 In our study, the effects of three anesthesia methods (SA, EA, and GA) on ureteral entrance and surgery success were compared.

Statistical analysis

Power analysis identified a minimum of 105 patients (35 per group) as the total sample size between the three groups with a maximum permissible error of 20% and a power of 83%, at a 5% significance level. All statistical tests were calculated using Statistics Package for Social Sciences version 25 (IBM SPSS^®, Chicago, IL). Kolmogorov–Smirnov and Shapiro–Wilk tests were performed for normality analysis. Differences in the categoric parameters between the three groups were calculated using the chi-square test. For numerical parameters, Kruskal–Wallis analysis was performed. For normally distributed numerical parameters, one-way ANOVA analysis was chosen. P < .05 was considered statistically significant.

Results

One hundred five patients were included in our study. There was no statistically significant difference for age, BMI, stone size, stone laterality, stone opacity, stone localization, preoperative creatinine levels, ASA score, and comorbidities between three groups. Stone density was statistically significantly different between three groups (P = .008) (Table 1).

Table 1.

The Demographic Values and Preoperative Features

	General anesthesia (n = 35)	Spinal anesthesia (n = 35)	Epidural anesthesia (n = 35)	P
Age (SD)	44.97 ± 14.6	45.80 ± 15.42	47.31 ± 14.75	.80
Gender, n (%)				.74
Female	12 (34.3)	10 (28.6)	13 (37.1)
Male	23 (65.7)	25 (71.4)	22 (62.9)
BMI (SD)	33.40 ± 22.84	37.41 ± 61.48	29.28 ± 7.09	.36
Stone density (HU) (SD)	1116.03 ± 294.94	1035.77 ± 371.76	854.60 ± 384.19	.008
Stone size (mm) (SD)	13.0 ± 3.81	12.7 ± 3.57	11.77 ± 2.87	.29
Preoperative creatinine (mg/dL)(SD)	0.98 ± 0.41	0.96 ± 0.33	0.91 ± 0.28	.68
ASA, n (%)				.42
ASA 1	11 (31.4)	13 (37.1)	8 (22.9)
ASA 2	24 (68.6)	22 (62.9)	27 (77.1)
Stone side, n (%)				.85
Right	15 (42.9)	15 (42.9)	17 (48.6)
Left	20 (57.1)	20 (57.1)	18 (51.4)
Stone location, n (%)				.89
Upper calix	1 (2.9)	0 (0)	1 (2.9)
Mid calix	2 (5.7)	1 (2.9)	3 (8.6)
Lower calix	5 (14.3)	4 (11.4)	1 (2.9)
Renal pelvis	12 (34.3)	13 (37.1)	14 (40)
UPJ	4 (11.4)	5 (14.3)	4 (11.4)
Upper ureter	11 (31.4)	12 (34.3)	12 (34.3)
Stone opacity, n (%)				.20
Opaque	33 (94.3)	30 (85.7)	28 (80.0)
Nonopaque	2 (5.7)	5 (14.3)	7 (20.0)
Comorbidity, n (%)	4 (11.4)	0 (0.0)	3 (8.9)	.16

Bold indicates values are statistically significant, p < 0.05.

ASA, American Society of Anesthesiologists; BMI, body mass index, HU, Hounsfield unit; SD, standard deviation; UPJ, ureteropelvic junction.

Lithotripsy and operation time were significantly lower in Group 3 (P = .001). Dilatation and stone access time were significantly lower in Group 1. There was no statistically significant difference for scopy time, success, VAS score at 8th and 24th hours and intraoperative and postoperative complications (Table 2).

Table 2.

Outcome of Retrograde Intrarenal Surgery Between Three Different Anesthesia Groups

	General anesthesia (n = 35)	Spinal anesthesia (n = 35)	Epidural anesthesia (n = 35)	P
Dilatation time (seconds) (SD)	73.51 ± 38.11	175.0 ± 72.56	192.85 ± 77.05	.00
Time to reach to stone (seconds) (SD)	120.28 ± 32.85	183.57 ± 80.40	200.0 ± 66.81	.00
Operation time (minutes) (SD)	54.77 ± 25.70	51.54 ± 25.86	35.25 ± 12.74	.001
Lithotripsy time (minutes) (SD)	30.64 ± 21.33	25.98 ± 20.99	14.55 ± 8.02	.001
Scopy time (seconds) (SD)	11.37 ± 8.06	11.77 ± 12.83	9.31 ± 5.08	.54
VAS score
8th hour (SD)	3.0 ± 2.2	2.77 ± 2.2	2.29 ± 1.8	.41
24th hour (SD)	1.77 ± 2.0	0.97 ± 1.1	1.06 ± 1.1	.39
Stone-free rates, n (%)	30 (85.7)	32 (91.4)	32 (94.3)	.6
Satava	5 (14.3)	10 (28.6)	10 (28.6)	.27
Stage 1	5 (14.3)	10 (28.6)	10 (28.6)	.27
Clavian				.69
Stage 1	1 (2.9)	5 (14.3)	5 (14.3)
Stage 2	3 (8.6)	2 (5.7)	1 (2.9)

Bold indicates values are statistically significant, p < 0.05.

SD, standard deviation; VAS, Visual Analog Scale.

To determine from which group the differences originated, dual comparisons were performed. In these comparisons, it was revealed that the differences for lithotripsy and operation time were due to Group 3. Moreover, the differences for dilatation and stone access time were due to Group 1 (Table 3).

Table 3.

Dual Comparisons to Determine Different Groups

	General versus spinal	General versus epidural	Spinal versus epidural
Dilatation time	0.00	0.00	0.68
Time to reach the stone	0.00	0.00	0.73
Operation time	0.93	0.001	0.005
Lithotripsy time	0.73	0.00	0.13

Bold indicates values are statistically significant, p < 0.05.

Data in the table shows the dual comparisons of three groups in order to determine the origin of the statistical difference. The values indicate the p values of the comparison.

Discussion

Technical advancements in the urinary system stone surgery have resulted in the developments in minimally invasive approach and decreased surgical trauma and increased comfort.¹¹ Minimal invasive approach advanced in anesthesia in the same way. Spinal, epidural, and the combination of two methods are used as minimal invasive anesthesia methods.⁷

RIRS is usually performed under GA. In GA, easy control of diaphragm and kidney movements may decrease complications during lithotripsy.⁷ However, there is not enough data for efficiency, success, and safety of anesthesia methods in RIRS procedure.

Ureteral access is an important step of RIRS. Unnecessary manipulations to enter into the ureteral orifices may cause complications and this may decrease ureteral entrance and surgery success. Park et al. analyzed α-adrenergic receptor subtypes in ureteral tissue and they found that there had been more adrenergic receptors in distal ureter than mid and proximal ureter.¹² According to this result, it might lead to insufficient relaxation and more manipulations might be needed for ureteral entrance and access to the stone in RA. Koo et al. thought that unrestrained force during primary ureteral access and UAS placement might increase the risk of ureteral injury. Moreover, they compared alpha blocker between RIRS group and control group. RIRS was performed under GA. In the alpha-blocker group, the force applied during ureteral accessing and complications were statistically significantly lower than the control group. UAS in a smaller diameter or prestenting before RIRS was recommended to avoid high UAS placement force and related complications.⁵

Parikh et al. compared segmental EA and GA in PNL. In 5 patients of EA group, additional anesthesia was needed while ureteral catheterization was performed. They concluded that EA does not block proprioception which may cause discomfort to patients in spite of an adequate sensory blockade. Segmental anesthesia was not enough in these patients so complementary GA was needed.^13,14 In our study, dilatation and access to the stone time were significantly lower in the GA group (P = .00). This showed insufficient relaxation and more manipulation in the RA group and better ureteral relaxation in the GA group.

Zeng et al. reported 70.6% SFR in GA group and 67.7% SFR in combined spinal-epidural anesthesia (CSEA) group in a prospective comparative study of 65 patients who underwent RIRS. They emphasized that two anesthesia methods had similar efficiency and safety.⁷ Similarly, Bosio et al. compared SA and GA methods in RIRS. SFR was 63.6% at the SA group and 48.6% at GA group. They found no significant difference between the two groups in terms of SFR, operation time, and complications.¹⁵ In our study, SFR in Group 1, 2, and 3 were 85.7%, 91.4%, and 94.3%, respectively. There was no statistically significant difference regarding SFR.

There was a significant difference for stone density, lithotripsy time, and operation time between the groups. This difference was due to Group 3 in which lithotripsy and operation time were lower than Group 1 and 2. This may be related to lower stone density in Group 3.^16,17

RIRS is a gold standard surgical method for kidney stones <20 mm. It is an efficient and safe method.¹⁸ In our study, there was no statistically significant difference for complications between the groups. Intraoperative mucosal injury and postoperative hematuria and infection were recorded as complications. High stage complications were not encountered in any patients. In the comparative anesthesia studies, anesthesia methods did not have any effects in terms of complications.^7,15,19,20

In the literature, VAS was lower in PNL operations in which RA was performed. There are studies reporting that analgesic need was lower in the spinal epidural block than GA in PNL patients.^19,21,22 Tangpaitoon et al. compared EA and GA in a prospective randomized study of 50 PNL cases. VAS at 1st and 4th hours was statistically significantly lower in the EA group. In the late period, there was no significant difference between the groups.²¹ In a review comparing anesthesia methods in PNL, spinal epidural technique was more advantageous than GA regarding postoperative pain and analgesic need.²³ Zeng et al. found there was no significant difference in VAS at 6th and 24th hours between the groups.⁷ In our study, we evaluated postoperative 8th and 24th hours VAS. VAS was higher in Group 1 but there was no statistically significant difference between the groups.

We planned this study according to the hypothesis that more manipulations might be required for the stages of ureteral access and reaching to the stone in RIRS in which RA methods were performed. Although this is not a ureteral pressure measurement study, ureteral access time was lower in Group 1 and this suggested that ureteral relaxation was better in GA.

There are studies reporting factors related to RIRS success.^24,25 However, there has not been a study evaluating the effect of anesthesia method on the success of ureteral access in RIRS. Our study is the first in the literature.

Conclusion

Although RA methods are performed to decrease the complications of GA, we found that ureteral relaxation was better in GA. Ureteral access and time to reach the stone were lower in GA for primary RIRS procedure. In these patients, GA may be recommended to decrease manipulations for the success of first ureteral access and time to reach the stone if there is not any contraindication.

Footnotes

Disclosure Statement

The authors declare that they have no conflicts of interest.

Funding Information

No funding was received for this article.

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