Comparisons of the safety and effectiveness of robot-assisted versus laparoscopic partial nephrectomy for central renal angiomyolipomas: A propensity score-matched analysis

doi:10.21203/rs.3.rs-2246502/v1

OBJECTIVE: To compare the safety and effectiveness of robot-assisted partial nephrectomy (RAPN) versus laparoscopic partial nephrectomy (LPN) in the treatment of central renal angiomyolipomas (AMLs).

METHODS: We retrospectively analyzed the clinical data of 103 patients who were treated with either RAPN or LPN for central renal angiomyolipomas between January 2017 and June 2022. Propensity scores were matched according to sex, age, laterality, body mass index (BMI), symptoms, diameter of tumor, location of tumor distribution, RENAL score, preoperative hemoglobin, preoperative serum creatinine, preoperative glomerular filtration rate (eGFR), chronic disease, previous abdominal surgery, preoperative SAE, ASA score, and duration of follow-up, and after matching, perioperative and prognostic data of the two groups were compared.

RESULTS: A total of 57 patients underwent RAPN, and 46 patients underwent LPN. Before matching, there were more complex AMLs in the RAPN group, and RENAL scores differed between the two groups (10 versus 9, P<0.001). After matching, the median warm ischemic time (WIT) in the RAPN group was significantly shorter than that in the LPN group (21.5 min versus 28 min, P=0.034), while the median operating time in the RAPN group was longer than that in the LPN group (190 min versus 160 min, P=0.02). The other indicators were not significantly different between the groups.

CONCLUSION: RAPN has a shorter warm ischemia time but a longer operating time for central renal angiomyolipomas. RAPN did not show superiority over LPN in terms of safety and effectiveness; it is safe and feasible to apply either surgical approach in the treatment of central renal angiomyolipomas.

central renal angiomyolipomas

robot-assisted laparoscopy

partial nephrectomy

propensity score

Renal angiomyolipoma, representing a family of tumors that originate from perivascular epithelioid cells, is a benign tumor composed of varying proportions of abnormal blood vessels, smooth muscle and adipose tissue^[1]. As one of the common benign renal tumors, AMLs account for approximately 10% of all renal tumors, and their incidence in the population is approximately 0.4%,Clinical prevalence of AMLs is significantly higher in women than in men ^[2]. Epidemiological studies have found that 80%-90% of AMLs are clinically sporadic, while only 10%-20% of AMLs are associated with tuberous sclerosis (TSC) and occur mainly in women.^{[3, 4]}. Due to the widespread use of imaging techniques, most patients are diagnosed incidentally as asymptomatic^[5]. The classic triad of symptoms in patients with renal angiomyolipoma is pain in the lower back and abdomen, a palpable mass, hematuria^[6]; other symptoms such as nausea and vomiting may be manifested. The main complication of renal angiomyolipoma is tumor rupture and bleeding, which can be life-threatening in severe cases^[7].

Surgical management of benign renal tumors remains somewhat controversial. In particular, low-risk AMLs detected early in the clinical setting are usually managed with observation and follow-up and do not require any treatment. However, surgical intervention is the generally accepted treatment option for AML patients who have tumors > 4 cm in diameter; these patients are at risk of cancer as well as rupture and bleeding and present with clinical symptoms such as hematuria and low back pain^[8-11]. The current surgical options include nephrectomy, open nephron-sparing surgery, and minimally invasive nephron-sparing surgery. The greatest advantage of surgery is that it can remove the lesion completely and has good long-term efficacy^{[12, 13]}. When the condition permits, even if there is a possibility of recurrence or metastasis after radical resection, all patients should consider the feasibility of nephron-sparing surgery (NSS), which is of great significance for the protection of renal function, especially in AML patients with anatomical or functional isolated kidney, impaired renal function, multiple tumors in both kidneys or AML combined with TSC.^[14-16].

At present, there is no clear definition of central renal angiomyolipoma, which generally refers to angiomyolipoma located in and around the renal hilum. Because of proximity to the renal arterioles and collecting system, it is much more difficult to preserve the renal unit and reconstruct the kidney when resecting central renal angiomyolipoma. In addition, the surgical procedure has a high complication rate, which is a challenge for urologists. After years of development of laparoscopic techniques and an accumulation of experience among urologists, laparoscopic techniques are increasingly used in the treatment of this type of complex renal angiomyolipoma. Compared with traditional open surgery, laparoscopic surgery is less traumatic and has a better prognosis for patients^[17]. Among the laparoscopic surgery approaches, the robot-assisted laparoscopic technique, with its unique 3D field of view and flexible robotic arm operation, has led to the further development of minimally invasive surgery, which is increasingly important in partial nephrectomy, especially for reconstructive surgery requiring repeated suturing^[18].

In conjunction with the relevant literature, clinical studies have now found that robot-assisted partial nephrectomy is safe and effective for the treatment of large renal angiomyolipomas^[19], and a successful case involving the use of a robot-assisted laparoscopic retroperitoneal approach for the removal of large hilar angiomyolipoma has been reported^[20]. However, studies comparing the safety and effectiveness of LPN and RAPN for central renal angiomyolipomas have not been reported. The aim of this study was to compare the safety and effectiveness of LPN and RAPN for central renal angiomyolipomas (AMLs) and to provide some reference and help in the clinical selection of surgical approaches for the treatment of central renal angiomyolipomas.

We retrospectively analyzed the clinical data of 103 patients with central renal angiomyolipomas who were clinically seen between January 2017 and June 2022, and the study was approved by the Institutional Review Board and the Ethics Committee. Inclusion criteria were as follows: 1） CT or MRI suggested that the lesion was located in and around the renal hilum; 2） absence of important contraindications to surgery and ability to tolerate surgery; 3）surgical procedure was posterior laparoscopic partial nephrectomy or robotic-assisted posterior laparoscopic partial nephrectomy; 4） diagnosis of renal angiomyolipomas confirmed by postoperative pathology; 5） no acute or chronic renal insufficiency. Exclusion criteria were as follows: 1）inability to tolerate surgery because of co-occurrence of cardiac, pulmonary and other important organ diseases; 2） severe coagulation dysfunction; 3）presence of pathology of renal epithelioid vascular smooth muscle lipoma or malignant biological behavior such as invasion and venous invasion; 4）AML occurrence combined with malignancy; 5）anatomical or functional isolated kidney; 6）confirmed diagnosis of tuberous sclerosis; and 7）missing clinical data. A total of 103 patient data points were obtained, and all patients provided informed consent. All patients underwent preoperative CT or MRI of the abdomen (Figure 1 shows the preoperative CT images of a 38-year-old female patient with a central malformation tumor). Patients’ baseline indicators included sex, age, laterality, body mass index (BMI), symptoms, tumor diameter, tumor distribution location, RENAL score, preoperative hemoglobin, preoperative serum creatinine, preoperative glomerular filtration rate (eGFR), chronic disease, previous abdominal surgery, preoperative SAE, ASA score, and duration of follow-up. Perioperative as well as prognosis-related indicators included postoperative hemoglobin, change in hemoglobin, postoperative serum creatinine, change in serum creatinine, postoperative eGFR, change in eGFR, no hilar clamping rate, WIT, operating time, transfusion rate, EBL, time to oral food, time to removal of catheter, time to removal of drainage, postoperative hospitalization days, postoperative complications rate, and recurrence rate. Renal scores were calculated from preoperative images (preferred CT), and all scores were completed by the same clinically experienced surgeon.

All procedures were conducted using a retroperitoneal approach and were performed by experienced urologists. (Figure 2 and Figure 3 show the intraoperative operation and postoperative pathological results, respectively, of RAPN in a 38-year-old female patient with central malformation tumor). Renal ischemia was achieved by clamping the renal artery, or if the off-clamp technique was applied, the renal artery was isolated, and a vascular clamp was used to control the renal artery as needed. Patients who experienced a SAE preoperatively were required to wait 3 months or longer before their procedures.

Propensity score matching analysis was used in this study to minimize selection bias and confounding factors. Logistic regression models were constructed by examining variables such as sex, age, laterality, body mass index (BMI), symptoms, diameter of tumor, location of tumor distribution, RENAL score, preoperative hemoglobin, preoperative serum creatinine, preoperative glomerular filtration rate (eGFR, calculated by CKD-EPI formula), chronic disease, previous abdominal surgery, preoperative SAE, ASA score, and duration of follow-up to estimate propensity scores; patients who received RAPN were matched 1:1 to those who received LPN. The two groups of patients were then compared for perioperative and prognostic-related indicators, including postoperative hemoglobin, change in hemoglobin, postoperative serum creatinine, change in serum creatinine, postoperative eGFR, change in eGFR, no hilar clamping rate, WIT, operating time, transfusion rate, EBL, time to oral food, time to removal of catheter, time to removal of drainage, postoperative hospitalization days, postoperative complications rate, and recurrence rate. Continuous variables were first tested for normality, and if they satisfied normal distribution criteria, they were described by the mean and standard deviation using the t test for two independent samples, while those for which data did not have a normal distribution were described by the median and interquartile ranges using the Mann–Whitney test. Categorical variables were reported using proportions and tested using the chi-square test. Statistical tests were two-sided and were considered statistically significant when P < 0.05. Statistical analyses were conducted using SPSS 26.0 software (SPSS; Chicago, USA).

In total, 57 patients underwent RAPN, 46 patients underwent LPN, and postoperative specimens from all patients were pathologically confirmed as renal angiomyolipomas. Table 1 presents a comparison of preoperative information before and after propensity score matching in the RAPN and LPN groups. Prior to matching, the two groups were distinguished by sex (P=0.590), age (P=0.278), BMI (P=0.094), laterality (P=0.791), symptoms (P=0.753), diameter of tumor (P=0.401), location of tumor distribution (P=0.372), preoperative SAE (P=1), chronic disease (P= 0.949), previous abdominal surgery (P=0.895), ASA score (P=0.166), preoperative hemoglobin (P=0.265), preoperative serum creatinine (P=0.341), preoperative eGFR (P=0.811), and duration of follow-up (P=0.328). Renal scores were higher in the RAPN group than in the LPN group (10 versus 9), with a statistically significant difference (P<0.001). After matching at 1:1, the baseline variables were better balanced across groups.

The number of patients in each group after propensity score matching was 27 in both the RAPN and LPN groups, and the perioperative and prognostic indicators are shown in Table 2. There were no statistically significant differences between the two groups in terms of postoperative hemoglobin (P=0.229), postoperative serum creatinine (P=0.653), postoperative eGFR (P=0.736), change in hemoglobin (P=0.740), change in serum creatinine (P=0.299), or change in eGFR (P=0.392). There were 3 cases in the LPN group without intraoperative renal artery block and 4 similar cases in the RAPN group, with no statistically significant differences (P=1). After removing zero ischemic cases, the median renal warm ischemia time was 28 min in the LPN group, the shortest was 8 min, and the longest was 36 min. In contrast, the median renal warm ischemia time in the RAPN group was 21.5 min, the shortest was 10 min and the longest was 40 min, with statistically significant differences between the two groups (P=0.034). The median operating time in the LPN group was 160 min, the shortest was 75 min, and the longest was 370 min, while the median operating time in the RAPN group was 190 min, the shortest was 95 min, and the longest was 325 min, with statistically significant differences between the two groups (P=0.02). There were 3 cases of intraoperative blood transfusion in the LPN group and 1 case in the RAPN group with no statistically significant differences (P=0.603). The median EBL in the LPN group was 150 ml, with a minimum of 50 ml and a maximum of 1500 ml, and the median EBL in the RAPN group was 200 ml, with a minimum of 30 ml and a maximum of 2000 ml; there were no statistically significant differences (P=0.152). The two groups had no statistically significant differences in time to oral food (P=0.315), time to removal of catheter (P=0.623), time to removal of drainage (P=0.592), or postoperative hospitalization days (P=0.916). One patient in the LPN group improved after surgery upon receiving blood transfusion subsequent to excessive bloody drainage, and 1 patient in the RAPN group improved after surgery with medication for incisional infection. There was one case of tumor recurrence during the follow-up period in both groups.

Renal angiomyolipoma is a common clinical disease encountered by urologists, and the choice of related surgical treatment modality is always discussed and studied according to the type of tumor. Minimally invasive nephron-sparing surgery has been a hot spot for modern research and innovation in urology since its emergence. From traditional open surgery to the emergence of laparoscopic surgery and robot-assisted surgery, the surgical treatment of kidney tumors has gradually become more precise and efficient, and the methods have become diversified. Even for patients with the same disease that require surgical intervention, the surgical complications and postoperative outcomes are markedly different depending on the surgical modality chosen. More studies have reported surgical interventions for AMLs involving RAPN, LPN, selective arterial embolization, laparoscopic aspiration, microwave ablation, radiofrequency ablation, and traditional open surgery; they have also included a variety of patients as study subjects, such as patients with giant, bleeding, and central tumor types, but the conclusions reached vary and need to be verified by more studies^{[2, 13, 21-24]}. However, there have been no studies that focus specifically on central renal angiomyolipomas. Partial nephrectomy is one of the most difficult urological procedures, and it is necessary to study the effectiveness and safety of RAPN and LPN in the treatment of the tumor.

With long relevant training, urological surgeons are more familiar with the retroperitoneal approach than the transabdominal approach, and for the partial nephrectomy covered in this study, the retroperitoneal approach can contribute to early vascular control, reduce bleeding, and reduce intestinal complications. In addition, arterial embolization has also been considered in recent years as a less invasive treatment and may be a better option for sporadic AMLs but is more prone to tumor recurrence, incomplete treatment, and the possible need for secondary surgery compared with surgical treatment^{[25, 26]}.

To our knowledge, this is the first propensity score-matched study comparing RAPN and LPN for central AMLs. The mean age at presentation in the matched LPN and RAPN groups in this study was 47.04 and 48.67 years, respectively, with a male-to-female ratio of 1:3.5 which is similar to that reported in the literature^{[27, 28]}. Because renal epithelioid angiomyolipoma (REAML) is also an uncommon type of AML and is characterized by malignant potential, it was included in the exclusion criteria to avoid influencing the study results. All study subjects with central tumors <4 cm in diameter were treated surgically for the following three reasons: 1) the possibility of renal cell carcinoma was suspected on preoperative imaging; 2) the tumor grew in a poor location and untimely management would seriously affect the patient's renal function; and 3) the patient strongly requested surgical treatment.

The median time (days) to oral food was 1 day in both groups, which can be assumed to be a result of the lesser intestinal impact of the retroperitoneal surgical approach and, therefore, faster recovery of gastrointestinal function in both groups. In addition, there was no statistically significant difference between the two groups in terms of time to removal of catheter (days) (P=0.623) or time to removal of drainage (days) (P=0.592). Harke et al.^[29] compared and analyzed both robotic transabdominal and retroperitoneal approaches for partial nephrectomy. The median length of stay was 9 (4-50) days in the transabdominal group and 8 (2-22) days in the retroperitoneal group, with a statistically significant difference (P<0.001). In this study, the median number of postoperative hospitalization days were 6 (6-7) days in the RAPN group and 6 (5-8) days in the RLPN group. Both groups had markedly shorter time than that reported in the above study for the transabdominal approach, and it can be concluded that the retroperitoneal approach can shorten the number of postoperative hospitalization days and reduce the total cost of hospitalization for patients compared to the transabdominal approach.

WIT is an important index for evaluating partial nephrectomy, and its duration is controversial in terms of its effect on postoperative renal function. Some studies have reported that WIT >30 min has a substantial influence on postoperative eGFR^[30]. Thompson et al.^[31] studied the relationship between WIT and chronic kidney disease after partial nephrectomy in 362 patients with isolated kidneys and finally arrived at 25 min as the ideal cutoff value for WIT. However, an analysis of a prospective study showed that a 30-60 min duration of renal warm ischemia does not cause severe functional loss in the kidney^[32]. Overall, an excessively long WIT may severely affect the recovery of renal function after surgery, so when performing partial nephrectomy, the WIT should be kept below 25 min when possible while ensuring complete tumor removal. In our study, with the removal of cases with no ischemia, the median WIT of the RAPN group was 21.5 min, which was significantly shorter than that of the LPN group at 28 min (P=0.034); we believe that this is mainly attributable to the unique 3D field of view and flexible robotic arm operation of the da Vinci robot. A previous clinical comparison study reported^[28] that the median WIT of LPN in the treatment of giant AMLs (62 patients with a mean tumor size of 8 cm and a mean renal score of 8) was 22 min, compared with only 17 min in the RAPN group (62 patients with a mean tumor size of 8 cm and a mean renal score of 9). Other similar clinical studies also reported WITs that were generally shorter than those reported in our study^[23].

In addition, the operating time is one of the indicators used to evaluate the surgery and can reflect the smoothness of the whole procedure. The median surgery time in the RAPN group in this study was 160 min, which was substantially shorter than that in the RLPN group (190 min) and representative of a difference that was statistically significant (p=0.02). The operating time in the RAPN group in this study was calculated without subtracting the robot loading time, which was approximately 10-30 min depending on the proficiency of the loading personnel; taking the intraoperative robot arm change time into account as well, the operating time in the RAPN group may not be longer than that in the LPN group. Overall, the operating time in both groups was longer than that of conventional partial nephrectomy, which we believe is a reflection of the high surgical difficulty in cases of central AML, and the median renal score of 9 in both groups confirms the complexity of this type of tumor; therefore, the longer operating time is relatively acceptable. In our study, there were individual patients who underwent embolization prior to surgery, and we took a propensity score-matched approach to minimize the resulting effects. However, differential efficacy resulting from whether or not NSS is performed immediately after SAE in AML patients has not been confirmed.

There was no statistically significant difference between the two groups in terms of postoperative hemoglobin (P=0.229), postoperative serum creatinine (P=0.653), postoperative eGFR (P=0.736), change in hemoglobin (P=0.740), change in serum creatinine (P=0.299), or change in eGFR (P=0.392), but there was still an important decrease in these indicators. This may be closely related to the complex anatomical location of central AMLs, which inevitably leads to damaging blood vessels when dealing with this type of tumor; further consequences are increased bleeding, increased ischemia of the renal parenchyma, and the inevitable removal of part of the normal renal parenchyma to ensure complete resection of the tumor, resulting in a postoperative decrease in hemoglobin and levels of renal function. It has been reported in the literature that the quality and quantity of intraoperatively preserved normal renal parenchyma is the main factor affecting postoperative renal function in PN, while WIT is a secondary factor along with preoperative patient baseline indicators such as renal function, tumor size and complexity^[33]. Therefore, preserving as much normal renal parenchyma as possible while shortening WIT is the key to preserving renal function.

Compared with laparoscopic surgery, robot-assisted surgery has been considered to be more delicate and less invasive and should be superior to laparoscopic surgery in terms of controlling intraoperative bleeding and blood transfusion rate. However, the results of this study showed no statistically significant difference between the two groups in terms of EBL (200 ml in the RAPN group and 150 ml in the LPN group, P=0.152) and transfusion rate (1 case in the RAPN group and 3 cases in the LPN group, P=0.603). The reason for this result may be related to the following three factors: 1) laparoscopic surgery was performed earlier in our hospital and partial nephrectomy occurred at a very mature stage; 2) the sample size of this study was small, so the data were not sufficient to show the difference between the two groups. In both groups, the surgical approach was not changed intraoperatively. After surgery and for clinical improvement, one patient in the LPN group was treated with blood transfusion due to excessive bloody drainage, and one patient in the RAPN group was treated with medication for incisional infection. There was one case of tumor recurrence during the follow-up period in both groups, and the difference was not statistically significant (P=1) .

Overall, choosing either the RAPN or LPN surgical approach is safe and feasible for patients with central AMLs. However, this study has some limitations, including its status as a retrospective clinical study with some confounding bias. Although we matched for variables such as sex, age, BMI, laterality, tumor diameter, and RENAL score, there may still have been some potential selection bias or confounding factors. For key variables, such as serum creatinine and eGFR, the results of this study did not show statistically significant differences, probably due to the small sample size of the study. In addition, the data in this study were from a single center, and the procedures were performed by different primary surgeons. Despite these limitations, the present study is the first study conducted to date on central renal angiomyolipomas, and large-sample, multicenter, prospective, randomized studies are needed to validate our findings in the future.

RAPN has a shorter WIT but a longer operating time in treating central renal angiomyolipomas. RAPN did not show superiority over LPN in terms of safety and effectiveness, but it is safe and feasible to apply either surgical approach in the treatment of central renal angiomyolipomas.

RAPN Robot-assisted partial nephrectomy

LPN Laparoscopic partial nephrectomy

PN Partial nephrectomy

SAE Selective arterial embolization

AML Angiomyolipoma

NSS Nephron-sparing surgery

EBL Estimated blood loss

WIT Warm ischemic time

GFR Glomerular filtration rate.

Acknowledgements

We thank American Journal Experts (AJE) for language editing service during preparation of this manuscript. We would like to thank the patient for his participation and hisconsent to the publication of the case details and associated images.

Authors’ contributions

Q-Q Z designed the study. Q-Q Z, Z-W L and Y L wrote the manuscript.

B-B G and T S reviewed the manuscript. Y-F L analysed the data and create the tables and graphs. Z-C Z collected and organized the patient data. Qi-Qi Zhu, Zhi-Wei Li, Ying Liu have equally contributed to this work. All of the authors read and approved the final manuscript.

Funding

Not applicable.

Availability of data and materials

The datasets used and/or analysed in the present study are available from the corresponding author upon reasonable request.

Ethics approval and consent to participate

This study was approved by the ethics committee of First Affiliated Hospital of Nanchang University, informed consent was obtained from all subjects and/or their legal guardian (s). All procedures were undertaken in accordance with the Helsinki Declaration and all methods were carried out in accordance with relevant guidelines and regulations in the declaration.

Consent for publication

Images are entirely unidentifable and there are no details on individuals reported within the manuscript.

Competing interests

All the authors in the present study declare that they have no competing interests related to the publication of this paper.

Author details

1.Department of Urology, the First Affiliated Hospital of Nanchang University,

Nanchang 330000, Jiangxi Province, China. 2.Suzhou Kowloon Hospital,Shanghai Jiaotong University School of Medicine, Suzhou 215028, Jiangsu Province, China

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Table 1: Comparison of preoperative data between the two groups of patients before and after propensity score matching

Variables	Before propensity score matching LPN(n=46) RAPN(n=57) P value	After propensity score matching LPN(n=27) RAPN(n=27) P value
Gender Male，n(%) Female，n(%)	0.590 10(21.7) 15(26.3) 36(78.3) 42(73.7)	1 6(22.2) 6(22.2) 21(77.8) 21(77.8)
Age(years)	46.11(11.83) 47.12(10.17) 0.278	47.04(11.81) 48.67(11.02) 0.819
BMI (kg/m2)	21.79(19.55,24.16) 23.07(20.69,24.85) 0.094	22.51(3.52) 22.01(2.90) 0.439
Laterality Left，n(%) Right，n(%)	0.791 23(50) 27(47.4) 23(50) 30(52.6)	0.785 13(48.1) 12(44.4) 14(51.9) 15(55.6)
Symptoms None，n(%) Abdominal pain，n(%) Hematuria，(%) Both，n(%)	0.753 16(34.8) 19(33.3) 29(63.0) 34(59.6) 0 2(3.5) 1(2.2) 2(3.5)	0.479 8(29.6) 11(40.7) 18(66.7) 15(55.6) 1(3.7) 1(3.7) 0
Diameter of tumor(cm)	4.95(4.00,6.43) 5.30(4.20,6.80) 0.401	4.8(4.3,6.3) 5.2(4.1,6.4) 0.897
Location of tumor distribution A，n(%) P，n(%) X，n(%)	0.372 24(52.2) 22(38.6) 9(19.6) 13(22.8) 13(28.3) 22(38.6)	0.562 15(55.6) 12(44.4) 4(14.8) 7(25.9) 8(29.6) 8(29.6)
RENAL score	9(8,9) 10(9,10) <0.001	9(9,10) 9(9,10) 0.451
Preoperative SAE，n(%)	4(8.7) 5(8.8) 1	0 1(3.7) 1
Chronic disease None，n(%) Hypertension，n(%) Diabetes，n(%) Both，n(%)	0.949 38(82.6) 47(82.5) 7(15.2) 7(12.3) 0 1(1.8) 1(2.2) 2(3.5)	0.740 24(88.9) 26(96.3) 2(7.4) 0 0 1(3.7) 1(3.7)
Previous abdominal surgery， n(%)	11(23.9) 13(22.8) 0.895	5(18.5) 8(29.6) 0.340
ASA score I、II，n(%) III、IV，n(%)	0.166 18(39.1) 15(26.3) 28(60.9) 42(73.7)	0.761 8(29.6) 7(25.9) 19(70.4) 20(74.1)
Preoperative hemoglobin	130.63(15.50) 130.93(12.66) 0.265	135(127,140) 128(121,140) 0.268
Preoperative serum creatinine	56.60(53.43,65.20) 59.30(53.15,71.35) 0.341	57.9(52.6,64.8) 57.3(51.7,68.9) 0.986
Preoperative eGFR	106.92(15.05) 104.29(15.13) 0.811	103.05(95.18,112.64) 104.01(97.23,117.96) 0.755
Duration of follow-up	46.50(35.00,56.75) 41.00(19.00,60.00) 0.328	50(36,59) 45(31,63) 0.849

Table 2: Perioperative and prognostic outcomes of patients in both groups after propensity score matching

Variables	LPN(n=27）	RAPN(n=27)	P
Postoperative hemoglobin	112.70(12.02)	111.93(12.93)	0.229
Change in hemoglobin	20.04(11.83)	17.78(10.57)	0.740
Postoperative serum creatinine	71.3(62.0,79.4)	72.6(63.9,90.1)	0.653
Change in serum creatinine	10.7(5.9,21.5)	15.7(7.9,20.6)	0.299
postoperative eGFR	93.28(72.59,105.04)	86.69(72.85,106.10)	0.736
Change in eGFR	8.71(5.33,27.2)	14.89(9.44,26.36)	0.392
No hilar clamping, n(%)	3(11.1)	4(14.8)	1
WIT (min)	28.0(20.0,29.0)	21.5(15.0,24.0)	0.034
Operating time (min)	160(120,190)	190(165,225)	0.02
Transfusion，n(%)	3(11.1)	1(3.7)	0.603
EBL (mL)	150(100,300)	200(100,300)	0.152
Time to oral food(days)	1(1,2)	1(1,2)	0.315
Time to removal of catheter(days)	4(3,5)	4(2,6)	0.623
Time to removal of drainage(days)	5(3,7)	5(3,6)	0.592
Postoperative hospitalization days	6(5，8)	6(6,7)	0.916
Postoperative complications，n(%)	1(3.7)	1(3.7)	1
Recurrence, n(%)	1(3.7)	1(3.7)	1

No competing interests reported.

Comparisons of the safety and effectiveness of robot-assisted versus laparoscopic partial nephrectomy for central renal angiomyolipomas: A propensity score-matched analysis

Status:

Version 1

Abstract

Figures

1. Introduction

2. Materials And Methods

3. Surgery

4. Outcome Measures And Statistical Analysis

5. Results

6. Discussion

7. Conclusion

Abbreviations

Declarations

References

Tables

Additional Declarations

Status:

Version 1