Retroperitoneal laparoscopic ureterolithotomy (RLU) is recognized as a method that can replace open ureterolithotomy as a first-line treatment for large impacted upper or midureteral calculi and as a salvage treatment for use when ureteroscopic removal of stone (URS) or extracorporal shock wave lithotripsy (ESWL) has failed [1,2,3]. When RLU is used to treat stones larger than 1 cm, the stone-free rate reaches 100%, which confirms RLU as an effective minimally invasive treatment modality [4,5,6,7,8]. The operation-related complications include mainly prolonged urine leakage and postoperative ureteral stenosis. Some authors support the idea of deploying a double J (D-J) stent after the stone is removed to prevent urine leakage and ureteral stricture [9,10,11], but others do not agree because D-J stenting has shown no correlation with the complication rate and increases the number of inconveniences to the patient, such as lower urinary tract symptoms, pain, and cost of cystoscopic removal of the D-J stent [4,12]. Because of this controversy, in the present study, we assessed the need for ureteral stents after RLU.

The mean age of the patients, serum creatinine level, and stone size (stent group, 17.64 mm; stentless group, 18.26 mm) were not significantly different between the two groups. Nine patients had a history of ESWL, and three had a history of URS. The demographic and clinical characteristics of the patients are shown in Table 1. The retroperitoneal approach was used in all patients by a single surgeon. Of the total 41 patients, the first 17 patients received a D-J stent and the next 24 patients did not. The mean operative time was significantly shorter in the stentless group than in the stent group (59.48 minutes vs. 77.88 minutes, p<0.001). Parenteral analgesic use and anticholinergic medication were observed in the stent group only (analgesics, 3 patients; anticholinergics, 2 patients). The mean blood loss, mean hospital stay, and mean drain removal day were not significantly different between the two groups. The stone-free rate was 100%, and no case was converted to open surgery. Prolonged urine leakage was reported in one patient in the stent group. The urine leak ceased without any intervention at 5 days postoperatively. No other complications, such as blood transfusion, febrile urinary tract infection, wound infection, or paralytic ileus, were reported.

The intra- and postoperative data of the subjects are shown in Table 2. At the 1-week and 3-month follow-up, eight patients complained of mild flank pain. The non-enhanced CT images of the eight patients showed no findings of hydroureteronephrosis or ureteral stricture. At the next follow-up, the patients' symptoms had spontaneously disappeared.

Less invasive laparoscopic ureterolithotomy (LU) has been recognized as the first-line treatment for 1.5-cm or larger upper or midimpacted ureteral stones [1,4,13,14,15] and as a salvage treatment for unsuccessful URS and ESWL [4,15,16]. When a skilled surgeon performs LU for a 1-cm or larger upper ureteral stone, the stone-free rate reaches 100%, as it did in this study [4,5,6,7,8]. Wickham [5] introduced laparoscopic retroperitoneoscopic ureterolithotomy in 1979, and Raboy et al. [9] performed laparoscopic transperitoneal ureterolithotomy for the first time in 1992. Compared with the transperitoneal approach, the retroperitoneal approach is reported to have better outcomes in terms of pain, ileus, port site hernia, and hospital stay [8,17,18,19]. Nevertheless, when the transperitoneal approach was used, a larger working space could be secured and the anatomical landmark could be easily confirmed, unlike in the retroperitoneal approach [20,21]. Upon consideration of the location of the ureteral stone and its anatomical relationship, the method of approach was determined before the surgery was performed. We believe that selection of the approach before the LU results in a shorter operative time and an enhanced success rate.

There is no definite answer to the question of whether a need exists to place a D-J stent after LU. A group of surgeons support the idea of placement of the D-J stent to prevent urine from leaking [8,9,10,11], but another group recommends that a stent not be used and instead that solely intracorporeal suturing be performed [4,12]. Karami et al. [22] compared the cases in which a D-J stent was used with those in which it was not used and reported that the use of the D-J stent significantly decreased the development of complications without extending the operative time. Accordingly, they supported the placement of a stent. However, Hammady et al. [6] compared a stent group with a stentless group and reported that the stentless group asked for a lower dose of analgesics and that their operative time was shorter and more economical without an increase in complications compared with the stent group. Accordingly, they supported the method without D-J stenting. Kijvikai and Patcharatrakul [23] suggested the use of the D-J stent only in cases of severe ureteral inflammation in which ureteral sutures cannot be performed. In 2011, we decided to start to perform RLU without D-J stenting according to the results of this study. However, we have not experienced a case in which suturing could not be performed because of severe ureteral inflammation.

Nouira et al. [2] recommended the use of a cold knife to make an incision on the ureter to prevent ureteral strictures. By contrast, other groups have suggested that an electric hook is easier to use in ureterotomy than a cold knife and does not cause any problems [6,7,22]. We thought that the use of the electric hook would not be absolutely free from the ischemic damage caused by capillary injury nor from direct tissue damage; thus, we used the cold knife for the longitudinal ureterotomy. Many surgeons have performed ureterotomy directly on the site of the bulge of the ureter [6,23,24], but we used a cold knife to make a longitudinal incision of the proximal ureteral bulge caused by the stone. In most cases in which the stone was impacted, the ureteral mucosa showed inflammation or ulceration. We thought that when the bulge was incised, suturing might be difficult, the possibility of recovery after the suturing might decrease, and the possibility of ureteral stricture due to adhesion at the suture site would increase. Thus, we incised the proximal ureter of the bulge. From our experience, the process of removing the stone by use of a right-angle clamp after incising the proximal ureter of the area of the bulge with a cold knife was not difficult. Comparative studies on the development of complications in cases that involved the use of a cold knife versus an electric hook, and of bulge site ureterotomy versus non-bulge-site ureterotomy, may be needed in the future.

The limitations of our study included the lack of an imaging study such as ultrasonography or CT scans to confirm ureteral strictures in all the subjects; these were only performed on the eight patients who complained of mild flank discomfort at the follow-up. None of the eight patients was confirmed to have had ureteral stricture or hydroureteronephrosis. Selective imaging studies were conducted because no patient had a significantly increased serum creatinine level after surgery and because of the high cost and the risk of radiation exposure of the imaging study. Another limitation was the short follow-up period; the shortest case was 5 months. Although the most extensive period of development of ureteral stricture after LU was not clearly investigated, the follow-up period in this study is considered short. In the future, long-term and large-scale studies may be needed.

Through this study, RLU was reconfirmed as a safe, effective, and minimally invasive treatment method for large stones or for cases of unsuccessful treatment with other methods. In this study, no complications such as urine leakage or ureteral stricture developed when the D-J stent was not used. We believe that laparoscopic ureteral stone surgery without D-J stenting is safe, economical, and less inconvenient for patients. In the future, large-scale studies that are focused on the development of complications, such as urine leakage and ureteral stricture, according to the surgical technique may be needed.