The feasibility of one-stage flexible ureteroscopy lithotripsy in solitary kidney patients with 1–3 cm renal stones and risk factors of renal function changes

Abstract

Purpose: To compare perioperative outcomes and long-term renal function changes between prior stenting (PS) and not prior stenting (NPS) before flexible ureteroscopy lithotripsy (f-URS) for solitary kidney patients. Methods: Solitary kidney patients with 10-30 mm renal stones were enrolled in this historical control study. Perioperative parameters and complications were compared. Stone-free was defined as the absence of any residual stones on a CT scan. Renal function changes were evaluated by estimated glomerular filtration rate (eGFR) and adjusted for body surface area. A decrease in the eGFR over 20% was identified as 'deterioration' in renal function. The follow-up period was at least 6 months. Logistic regression was used to identify risk factors of renal function deterioration. Results: Of the 76 patients included, 40 cases experienced prior stenting before f-URS. The average stone diameter was 16.8 ± 4.7 mm, ranging from 10.0 to 28.4 mm. Initial SFR was 85.0 and 83.3% in the PS and NPS groups, respectively (p ¼ 0.842), while SFR after the second procedure was 97.5 and 94.4% (p ¼ 0.926). Seven PS and 5 NPS patients developed complications (p ¼ 0.666). At the postoperative 6 months, seven patients showed a deteriorated renal function. Surgical time in minutes was identified as a risk factor for renal function deterioration after the operation (OR ¼ 1.061, 95% CI: 1.015-1.109, p ¼ 0.009, per minute). Conclusion: It appears that one-stage f-URS without PS could be feasible for 10-30 mm renal stones in solitary kidney patients, and less surgical time might be beneficial to protect renal function.

Novel scoring system combined with a virtual reality technique for the preoperative evaluation of the stone-free status after flexible ureteroscopy: the H.L.P.E.S. score

“…For each factor, the cut-off values are taken as the boundary values. Each variable is assigned a value in reference to the previous literature and the original S.O.L.V.E score [ 4 – 9 ]: (S)tone surface area (1–2 points); renal (P)elvis volume (1–2 points); (L)ength of the calyces funnel (1–2 points), for which the pyelolithiasis score should be 0; pelvic calyceal (H)eight (1–2 points), for which pyelolithiasis is recorded as 0 points; and CT value as the evaluation standard of the (E)ssence of stone (1–2 points). The specific scores are shown in Table 3 .…”

“…The determinants of SFR after FURS are not uniform and are influenced by multiple factors, including stone characteristics and renal anatomy [ 4 , 5 ]. Currently, there are many reports in the literature on this issue [ 4 – 9 ]. Previous scoring systems including STONE [ 10 ], CROES Calculation Chart [ 11 ], and Guy’s stone score, [ 12 ] among others, are applicable only to percutaneous nephrolithotomy, and there is a lack of evidence for a predictive model for SFR after FURS [ 13 ].…”

Reply to ‘Is one-stage f-URS without prior stenting really safe for solitary kidney patients with 1–3 cm renal stones?’

“…This opinion has been verified in patients with bilateral kidneys. Similarly, in our study including only these patients with a solitary kidney, the success rate of UAS placement was also relatively higher in the PS group, even though the statistical difference was not significant [ 2 ]. However, due to ureteral tissue irritation and irregular peristalsis, indwelling ureteral stents might result in some common complications such as discomfort, lumbago, urinary tract infection, hematuria, and encrustation [ 6 ].…”

“…In reply, we would like to thank Dr. Yuzhuo Li and his colleague for their interest and constructive comments [ 1 ] on our article [ 2 ]. The management of renal stones in patients with a solitary kidney is full of challenges and the goal of surgery may mainly include improving stone-free rate (SFR), decreasing complications, and protecting renal function [ 3 ].…”

“…The single-use f-URS and small-sized UAS have both been widely used in our stone center in recent years, which are also applied in many solitary kidney patients successfully. As for the uncertain ureteral conditions, on one hand, ureteric balloon dilation is useful for patients with a mildly narrow or tortuous ureter; on the other hand, ‘when solitary kidney patients experience some comorbidities such as ureteral obstruction and kidney injury, PS before f-URS may be relatively safer and preferred’, which has been stated in the ‘discussion’ of our paper [ 2 ]. Therefore, PS might be necessary for partial patients with complications instead of all solitary kidney stone patients.…”