Evaluation of renal cyst treatment using retroperitoneal laparoscopic decortication

Use your smartphone to scan this QR code and download this article ABSTRACT Introduction: Renal cyst is a commondisease of the renal parenchyma. Themanagement options include percutaneous aspiration with or without sclerotherapy, open surgery, and laparoscopic decortication of renal cyst. Laparoscopic renal cyst decortication is a safe and effective alternative with a high success rate. This study aimed to evaluate renal cyst treatment by retroperitoneal laparoscopic decortication. Methods: This was a prospective study of patients with asymptomatic renal cyst size greater than 60 mm or symptomatic renal cyst size less than 60 mm in their greatest dimension. These patients underwent retroperitoneal laparoscopic decortication and were admitted at the University Hospital, Can Tho General Hospital (Viet Nam), and Can Tho Central General Hospital (Viet Nam), from September 2018 to May 2020. Renal cysts were localized and characterized by ultrasonography and computed tomography (CT). Symptomatic success rate, radiologic success rate, and complication of procedure were noted. Each patient was reassessed with clinical and ultrasonography examinations at 3 months postoperatively. Results: 33 patients underwent retroperitoneal laparoscopic cyst decortication; this included 11males (33.3%) and 22 females (66.7%). Themean age of patients was 58.48± 9.36 years. Flank pain was a common clinical symptom at presentation in all patients. Most of the cysts were located in the left kidney (39.4%), in the lower pole (54.6%), and in a single cyst (87.9%). The mean cyst diameter was 80.09 ± 27.03 mm. Cysts were classified I with the Bosniak classification. The mean operative time was 69.39 ± 16.94 minutes. Operative time in patients with cyst diameter ≥ 60 mm was statistically significantly longer than in patients with cyst diameter < 60mm (p = 0.004). Themean hospital stay time was 8.24 ± 2.84 days. Symptomatic success was achieved in 90.1% of patients and radiographic success on ultrasonography was achieved in 84.8%. The operation was successfully completed by laparoscopy in all cases. Conclusion: Retroperitoneal laparoscopic cyst decortication is effective for the treatment of renal cysts. The operation was successfully completed via laparoscopy in all cases.


INTRODUCTION
Simple renal cyst is a common non-neoplastic disease of the renal parenchyma. It has been estimated that the prevalence of renal cysts increases with age. The management options for renal cyst include percutaneous aspiration with or without sclerotherapy, open surgery, and laparoscopic cyst peeling [1][2][3] . Simple aspiration or sclerotherapy is a minimally invasive procedure; however, the recurrence rate is very high. Open surgery offers a high success rate; however, it presents an invasive procedure with the comorbidity of flank incision 4,5 . The laparoscopic technique, however, not only has a high success rate but is also characterized by minimal invasiveness, low morbidity, and early recuperation, making it a preferred treatment 4,5 . This method has been widely applied in Vietnam, in general, and Can Tho city, in particular 6,7 . In fact, the Can Tho University of Medicine and Pharmacy Hospital, Can Tho General Hospital, and Can Tho Central General Hospital have performed retroperitoneal laparoscopic decortication for renal cysts for over 9 years. Nevertheless, there have been no reports to evaluate the efficacy of this method in renal cyst treatment. Therefore, the aim of this study was to investigate the efficacy renal cyst treatment by retroperitoneal laparoscopic decortication.

Patients
This was a prospective study of renal cyst patients who underwent retroperitoneal laparoscopic decortication and were admitted to the University Hospital, Can Tho General Hospital, and Can Tho Central General Hospital, from September 2018 to May 2020. All patients who agreed to participate in the study were confirmed by signing a consent form for the study.  The surgery indicators included  patients with asymptomatic renal cyst size greater  than 60mm or with symptomatic cyst (such as renal  pain, renal lump, hypertension, or hematuria), and renal cyst size less than 60 mm in the greatest dimension with simple cysts (Bosniak I and II classification). Exclusion criteria: Patients were excluded if they had a history of previous renal surgery or complicated cysts (Bosniak III and IV), or asymptomatic cyst size less than 60 mm in the greatest dimension.

Procedure
Renal cysts were localized and characterized by ultrasonography and computed tomography (CT). Symptomatic success rate, radiologic success rate, and complication of procedure were noted. Each patient was reassessed with clinical and ultrasonography examinations at 3 months postoperatively. After the induction of general anesthesia, the patient was catheterized and positioned in the standard left/right lateral decubitus position. All the patients were successfully managed by retroperitoneal laparoscopic decortication using a 3-port technique. The first port was inserted 1 cm below and posterior to the tip of the 12 th rib. A 2 cm deep stab incision was made down to the thoracolumbar fascia and a homemade balloon was created by tying a fingerstall surgeon glove, inflated with 200 to 300 mL air, and kept for about 5 minutes to create adequate working space in the retro-peritoneum. After deflating of the balloon at the retroperitoneal end, it was removed. Then, a 1.0 cm blunt-tip trocar was placed and a 30degree laparoscope was inserted through the sheath. Carbon dioxide was insufflated to 12 mmHg and the initial retroperitoneoscopy was performed for orientation and confirmation of the anatomic landmarks. Typically, 2 working ports (0.5 and 1.0 cm, respectively) were placed under laparoscopic camera. At one lumbar angle, a grasping forceps was inserted, and at another angle more anteriorly (along or more medial to the anterior axillary line, at least 3 cm above the iliac crest to allow maneuverability), a dissecting forceps or clip applier was inserted via this trocar. The direction of dissection depended on the location of the renal cyst (anterior, posterior, or central aspect; upper, middle, or lower pole). Gerota's fascia was incised over the area corresponding to the position of the cyst. The overlying perinephric fat was dissected from the cyst and the surrounding parenchyma. Then, the cyst was unroofed 1 to 1.5 cm adjacent to the renal parenchyma, leaving behind the floor of the cyst. The cyst fluid was aspirated and the cystic wall was sent for pathologic analysis. Subsequently, the 18 French catheter used for drainage was placed in the retro-peritoneum, and the port sites were cleansed and closed.

Statistical analysis
Statistical analysis was performed with a commercially available statistical program (SPSS 20.0 with the Pearson χ 2 and Student's t test for independent variables; p < 0.05 was considered statistically significant.

Study ethics
The study was reviewed and approved for implementation by Can Tho University of Medicine and Pharmacy under Decision No. 451/Decision-CTUMP (dated 20 March 2018).

RESULTS
33 patients underwent retroperitoneal laparoscopic cyst decortication; this included 11 males (33.3%) and 22 females (66.7%). The mean age of patients was 58.48 ± 9.36 years, as shown in Table 1. Flank pain was a common clinical symptom at presentation in all patients. Most of the cysts were located in the left kidney (39.4%), in the lower pole (54.6%), and in a single cyst (87.9%). The mean cyst diameter was 80.09 ± 27.03 mm with cyst diameter ≥ 60 mm in 87.9%. Cysts were classified as I by the Bosniak classification. Most of the cysts were located in the left kidney (39.4%), followed by right kidney (30.3%) and bilateral kidney (30.3%), with χ 2 = 0.545 and p = 0.761, indicating no statistically significant difference. Most of the cysts were located in the lower pole (54.6%), followed by upper pole (42.4%) and peripelvic (3%), with χ 2 = 14.364 and p = 0.001, indicating that the differences were statistically significant. Indeed, 87.9% of patients had only 1 cyst and 12.1% had 2 cysts (χ 2 = 18.939, p < 0.001); these results were considered as statistically significant differences. The mean cyst diameter was 80.09 ± 27.03 mm, which included cyst diameter ≥ 60mm in 87.9% of patients and cyst diameter < 60 mm in 12.1% patients (with χ 2 = 18.939, p < 0.001; differences were statistically significant). All of the cysts were classified as I with the Bosniak classification. The mean operative time was 69.39 ± 16.94 minutes. Operative time in patients with cyst diameter ≥ 60 mm was longer than that of patients with cyst diameter < 60mm (p = 0.004; the difference were statistically significant). The mean hospital stay time was 8.24 ± 2.84 days. Symptomatic success was achieved in 90.1% of patients and radiographic success on ultrasonography was achieved in

ACKNOWLEDGMENTS
We would like to thank the leaderships of Can Tho University of Medicine and Pharmacy, the school's scientific council for allowing us to conduct this research. At the same time, we would like to express our sincere thanks to the leadership and colleagues of three hospitals including University Hospital, Can Tho General Hospital, and Can Tho Central General Hospital for their dedicated help in the process of collecting research data. In particular, we would like to express our sincere thanks to the patients who volunteered to participate in our research.

AUTHOR'S CONTRIBUTIONS
UTH: The main study author designed the study, found references, collected and analyzed data, and wrote and reported the research results. CVD: Coauthor and supervisor edited and contributed the research ideas. NKL: Co-author revised the article and supported the data. All authors read and approved the final manuscript.

AVAILABILITY OF DATA AND MATERIALS
Data and materials used and/or analyzed during the current study are available from the corresponding author on reasionable request.

ETHICS APPROVAL AND CONSENT TO PARTICIPATE
This study was conducted in accordance with the amended Declaration of Helsinki. The institutional review board approved the study, and all participants provided written informed consent.

CONSENT FOR PUBLICATION
Not applicable.