Aspiration-Sclerotherapy Versus Laparoscopic Deroofing in the Treatment of Symptomatic Renal Cysts: A Systematic review and meta-analysis

Background: Renal cyst is prevailing around the world and symptomatic renal cysts are recommended to be treated in the EUA guidelines. Currently, aspiration-sclerotherapy (AS) and laparoscopic de-roofing (LD) are the main therapies of symptomatic renal cysts. This article aims to compare the clinical efficiency between them in the management of renal cysts through meta-analysis of comparative studies. Method: A comprehensive literature search was performed by PubMed, MEDLINE, EMBASE and the Cochrane Library to ascertain the relevant studies published up to March 2019. Articles with English full-text comparing aspiration-sclerotherapy and laparoscopic de-roofing in renal cyst treatment were included. Results: Our searches of literature generated 6 studies (1547 patients incorporated) comparing AS with LD in the impacts of renal cyst therapy. Of these, 6 studies contained 1106 and 441 patients who were treated with AS and LD, respectively. The outcome of this meta-analysis indicated that although AS group had shorter treatment time (MD-51.10; 95% CI-73.01 to -29.20; p<0.01), radiological successful rate (RR: 0.64; 95%CI: 0.53 to 0.77) are higher in LD group, which also had less recurrence rate (RR: 4.96; 95%CI: 2.28 to 10.81; p<0.01). No statistically significant difference was showed in symptomatic successful rate (RR: 0.90; 95%CI: 0.79 to 1.03P=0.13) and complications (RR: 2.11; 95% CI: 0.47 to 9.52; P=0.33). Conclusion: In our meta-analysis, laparoscopic de-roofing is superior to aspiration-sclerotherapy in radiological successful rate and recurrence, but the treatment time is longer.

renal cysts was 7.7% under ultrasonography and higher number of renal cysts in males.
Moreover, Kong et al. [3] managed a large sample cross-sectional study about renal cysts, whose results showed the prevalence of it among Chinese adults was 10.5%, and even the existence of it significantly correlated with renal damage and the estimated glomerular filtration rate (eGFR) of 5.7% patients who with more than one renal cyst was decreased under 60 ml/min/1.73m 2 . Nowadays according to the Bosniak renal cysts classification, cysts of Bosniak Ⅲ, Ⅳ are symptomatic and even malignant to some extent. [4] In the EUA guidelines, the symptomatic renal cysts (Bosniak Ⅲ, Ⅳ) are recommended to be treated through surgery. [5] Therefore, we should pay attention to the treatments of symptomatic renal cysts in particular.
Aspiration-sclerotherapy (AS) and laparoscopic de-roofing (LD) are main therapies for symptomatic renal cysts. [6] LD is usually applied to large compressive cysts or increasing in cyst`s size, while AS may be superior in time-consuming or cost but its reliability has not yet been ascertained.
[7] Based on the current clinical literature, we first conducted this meta-analysis to compare AS with LD in the management of renal cysts.

Statistical analysis
This meta-analysis compares symptomatic successful rate, radiological successful rate, treatment time, complications and recurrence of aspiration-sclerotherapy versus laparoscopic de-roofing during the cure of renal cysts. Review manager (RevMan) software version 5.3 was used to evaluate the outcomes of each study for comparison. Risk ratio (RR) and mean difference (MD) were used to estimate dichotomous and continuous variables separately. If results are shown with 95% confidence interval (CI), the standard deviation was calculated by the statistical calculation declaimed by Hozo and colleagues [10]. Heterogeneity of these researches was evaluated using the chi-square test. I 2 >50% was regard as high heterogeneity so that we took random effect model; I 2 <50% was regard as low heterogeneity so that we took fixed effect model. A p-value <0.05 was considered as statistically significant.

Study characteristics
Our researches of literature generated 6 studies[11-16] comparing AS with LD in the effects of renal cysts treatment. These studies contained 1106 and 441 patients who were treated with AS and LD respectively. Characteristics (including first author's name, publication year, country, type of treatments, sample number, age, ratio of male, diameter of cyst and length of follow-up) and quality assessment of all studies are summarized in Table 1. Meta-analysis results of these 6 studies are elaborated in Figure 2.
Flow chart diagram demonstrating the strategy of search and selection was shown in

Symptomatic successful rate
Four studies [11][12][13][14] involving 1498 patients compared the cure rate of symptom between AS group and LD group. The result of this meta-analysis showed that no statistically significant difference between them (random effect model; RR: 0.90; 95%CI: 0.79 to 1.03; P=0.13) with a high heterogeneity (P=0.001; I 2 =82%; Fig. 2A). The sensitive analysis claimed a statistical significant difference between them (random effect model; RR: 0.96; 95%CI: 0.93 to 0.99 P=0.01) and the heterogeneity of that reduced to zero after excluding the study of Bas et al.[12] This demonstrated that this meta-analysis was influenced by this study.

Radiological successful rate
Two studies [11,12] including 264 patients compared the successful rate of radiology between AS group and LD group. A meta-analysis of these studies stated that LD is

Treatment time
Three studies [11,13,14] involving 1314 patients compared the treatment time between AS group and LD group. The result of meta-analysis showed that AS was associated with a significantly lower time-consuming in the therapy procedure (random effect model; MD -51.10; 95% CI -73.01 to -29.20; p<0.01), but the heterogeneity of it was high (P<0.01; I 2 =99%; Fig. 2C).

Complications
Six studies [11][12][13][14][15][16] containing 1547 patients compared the number of complication events between AS group and LD group. The outcome of our meta-analysis illustrated that no statistically significant difference was found between these two groups (random effect model; RR: 2.11; 95%CI: 0.47 to 9.52; P=0.33) with a slightly high heterogeneity

Discussion
Currently, comparisons of the effects between AS and LD in the treatment of renal cysts were lacking, therefore, we first conducted a meta-analysis on this subject. Statistics in Table 1 show that renal pain would be the primary presenting symptom among  separately, which are presented in Table 2. Ethanol contacting the cyst wall causes protein degeneration, cell death as well as inflammatory fibrosis so that patients should keep 5 to 10 minutes at least in each position according to the cyst size and volume. [21] Therefore, the difference among them may be ascribable to the different treatment procedure, which also was hard to make a standard therapy.
In addition to this, although study reported by Zhong et al. [22] shows no recurrence was observed after AS treatment, in the outcome of our meta-analysis, it is remarkably higher in AS group than LD group in the matter of recurrence. The reason why simple fluid aspiration was ineffective and even promoted the recurrence of cyst is that the renal cyst epithelium was not destroyed by sclerosing agents completely and adhered to each other, thus the remained cyst wall can still secrete fluid. [23] In terms of LD therapy, it has the advantage in high rate of cure and low rate of recurrence and could be thought as a complete treatment of renal cysts.
[25] collected the data of renal cyst patients treated with LD in their center and 91.3% patients reached symptomatic and radiological success while only one patient got recurrence, which was consistent with our meta-analysis results. As LD operation preferred to excising the complete cyst including all cyst walls, so the leaved tissues were out of secreting function, which lead high cure rate an low recurrence rate.
[26] Hence, LD could be the standard in the management of renal cysts, especially suited for patients failed after aspiration-sclerotherapy. [27] To enhance the efficiency of LD treatment, Lai and colleagues [28] studied the impacts of perirenal pedicled fat tissue wadding technique (PPFTWT) on the recurrence rate during this surgery operation, they found that LD using PPFTWT can decrease the rate of cyst recurrence. Inserting fat tissue into the cavity of the cyst and fixing it prevented the cyst wall from adhering to the residuary cyst wall or surrounding tissue, and contributed to the secretion drainage and absorption of the remaining cyst wall, thus declined the risk of cyst recurrence.
[29] Therefore, laparoscopic de-roofing with PPFTWT may be a better choice in the treatment of renal cysts.
When it comes to complications, our statistics showed there was no significant difference between AS group and LD group, both of which can cause post-treated complications such as fever, infectious, pain, hemorrhage. On account of ethanol as the common sclerosing agents in AS treatment, patients may get alcohol intoxication and lose consciousness even injury femoral nerve due to the rupture of cysts.
[30] As for LD therapy, vessels damage and subcutaneous emphysema may happen to patients during the process of cyst ablation and establishing pneumoperitoneum. [31] The limited included studies in our meta-analysis and the heterogeneity of some date are two main limitations of this study. Due to the lack of researches on the comperation between AS and LD, we included six articles merely and the patients selection bias or difference of provider training/experience could be limitations. Therefore, further studies are expected to confirm our outcomes. As for the heterogeneity, in the study of Bas et al.
[12], the difference of treatment techniques may contribute to the heterogeneity in symptomatic successful rate. Besides, in terms of complication rate, the researches of

Conclusions
Summarily, aspiration-sclerotherapy takes the advantage of less time-consuming, few potential injuries caused by surgery and only local anesthesia demanding, which is more suitable for elder people with renal cysts. Nevertheless, higher radiological cure rate and renal cyst usually means malignancy: results from a cohort study. World journal of surgical oncology 2014, 12:316.

19.
Monville H, Wagner L, Dibo D, Soustelle L, Muyshondt C, Droupy S, Costa P:  Tables   Table 1: Author Country Treat -ment Sample number (n) Figure 1 Flow chart of the strategy of search and selection Figure 2 Flow chart of the strategy of search and selection