Objective: To retrospectively evaluate appropriate treatment for patients with symptomatic caliceal diverticular calculi, by comparing the therapeutic outcomes for those undergoing minimally invasive percutaneous nephrolithotomy (MPCNL) and flexible ureterorenoscopy (F-URS).
Methods: From March 2009 to May 2014, 36 consecutive patients with caliceal diverticular calculi were divided into 2 groups: 21 patients underwent MPCNL, and 15 were treated by F-URS. All procedures were performed by one surgical group, which ensured relatively constant parameters. Patient characteristics, operative time, hospital stay after surgery, stone-free rate, symptomatic improvement rate, complications, diverticular obliteration, and stone composition were analyzed retrospectively in the 2 groups.
Results: Patient preoperative variables were comparable between the two groups, with no significant difference (P > 0.05). Mean operative time was 136.9 ± 22.8 min in the MPCNL group and 117.3 ± 24.3 min in the F-URS group (P = 0.019). Hospital stay was significantly longer in the MPCNL group than in the F-URS group (9.4 ± 3.1 vs. 6.9 ± 2.1 days, P = 0.010). The stone-free rates after MPCNL and F-URS were 90.5% (19/21) and 60.0% (9/15), respectively (P = 0.046). Additionally, 71.4% (15/21) of patients in the MPCNL group and 46.7% (7/15) of patients in the F-URS group had symptomatic improvement at the 6-month follow-up (P = 0.175); the rates of complications in the 2 groups were 19.0% (4/21) and 13.3% (2/15), respectively (P = 0.650). Complete diverticular obliteration was achieved in 16 (76.2%) cases in the MPCNL group and 5 (33.3%) cases in the F-URS group (P = 0.017). The distributions of calcium oxalate and hydroxyapatite in the stones were 66.7% (14/21) and 33.3% (7/21), respectively, in the MPCNL group; however, the distributions in the F-URS group were 46.7% (7/15) and 53.3% (8/15), respectively (P = 0.310).
Conclusion: MPCNL is an effective method for the treatment of caliceal diverticular calculi. However, F-URS is an alternative technique in selected patients with a patent infundibulum, despite lower stone-free rates than with MPCNL. Fulguration of the diverticular lining with a high-power holmium laser and permitting the cavity to collapse are useful to increase the chance of diverticular obliteration.
Keywords: Caliceal diverticular calculi; Flexible ureterorenoscopy; Minimally invasive percutaneous nephrolithotomy.