Impact of lower pole calculi in patients undergoing retrograde intrarenal surgery.
OBJECTIVE
To assess if the presence of a lower pole stone (LPS) decreases the stone-free (SF) rate following retrograde intrarenal surgery (RIRS). The second purpose was to assess the result of RIRS for LPS and to identify predictors of SF status.


METHODS
We retrospectively analyzed 205 procedures in 162 patients with renal stones treated by RIRS between January 2010 and January 2013 at a single institute. The SF status was defined as no residual fragments. Independent-sample t-tests and Chi-square tests were used for comparisons of means and proportions, respectively, between patients with or without LPS. Logistic regression models were used to assess prognostic factors influencing SF status in cases of LPS.


RESULTS
LPS were present in 89 (54.9%) patients. There were no differences between patients with or without LPS regarding the mean operative time (p=0.77), the surgeon's experience (p=0.522), the length of hospital stay (p=0.269), and the SF rate (p=0.224). SF status after RIRS in patients with or without LPS was 74.1% and 78% (p=0.224), respectively. In the case of LPS, the presence of multiple stones and a history of percutaneous nephrolithotomy (PCNL) were predictive factors for occurrence of residual fragments in univariate analysis (p=0.037 and p=0.015). In multivariable analysis, only the presence of multiple stones remained as a predictive factor (p=0.027; HR=3.2), whereas a trend was observed when there was a history of PCNL (p=0.07; HR=3).


CONCLUSIONS
The presence of a LPS does not alter the SF rate of RIRS even in cases of early experience. RIRS for LPS appears to be an effective technique, but special attention should be given to patients with multiple stones and/or a history of PCNL.
Department of Urology, Angers University Hospital , Angers, France .
Francois
F
Martin
Nicolas
N
Hoarau
Souhil
S
Lebdai
Thomas
T
Pichon
Denis
D
Chautard
Thibaut
T
Culty
Abdel Rahmene
AR
Azzouzi
Pierre
P
Bigot
D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000473:pathology* / Q000601:surgery*; D007902:Length of Stay; D008096:Lithotripsy; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous; D061646:Operative Time; D019990:Perioperative Care; D011183:Postoperative Complications; D012189:Retrospective Studies