Simsekoglu MF. et al., 2025: Lower Pole Stones Are Associated with Low Stone-Free Rates in Retrograde Intrarenal Surgery: A Myth or Fact? - A Matched Case-Control Study from the RIRSearch Group.

Muhammed Fatih Simsekoglu 1, Oktay Özman 2, Hakan Cakir 3, Kerem Teke 4, Önder Çınar 5, Murat Akgül 6, Mustafa Bilal Tuna 7, Cem Başataç 8, Eyüp Burak Sancak 9, Duygu Sıddıkoğlu 10, Cenk Yazici 11, Barbaros Başeskioğlu 12, Haluk Akpinar 8, Bulent Onal 1
1Urology, Cerrahpasa School of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey.
2Urology, Group Memorial Hospitals, Bahcelievler Hospital, Istanbul, Turkey.
3Urology, Acibadem Fulya Hospital, Istanbul, Turkey.
4Urology, School of Medicine, Kocaeli University, Kocaeli, Turkey.
5Urology, Group Medicana Internationals, Samsun Medicana Hospital, Samsun, Turkey.
6Urology, Health Sciences University Umraniye Training and Research Hospital, Istanbul, Turkey.
7Urology, Acibadem Maslak Hospital, Istanbul, Turkey.
8Urology, Group Florence Nightingale Hospitals, Istanbul, Turkey.
9Urology, School of Medicine, Canakkale Onsekiz Mart University, Çanakkale, Turkey.
10Biostatistics, Canakkale Onsekiz Mart University, School of Medicine, Çanakkale, Turkey.
11Urology, School of Medicine, Tekirdag Namik Kemal University, Tekirdag, Turkey.
12Urology, Acibadem Eskisehir Hospital, Eskisehir, Turkey.

Abstract

Introduction: There are conflicting results in the literature regarding the efficacy of retrograde intrarenal surgery (RIRS) in lower pole stones. This study aimed to evaluate RIRS outcomes in lower pole stones by forming matched case-control groups.

Methods: The data of 491 patients who were diagnosed with kidney stones and underwent RIRS were retrospectively included in the study. A total of 209 patients with lower pole stones (Group 1) and 282 patients with pelvic stones (Group 2) were matched at a 1:1 ratio in terms of stone burden, stone density, preoperative double-J stenting status, and a previous history of shock wave lithotripsy, yielding 159 patients in each group. A computed tomography scan was performed to evaluate the stone-free status. The primary outcome was stone-free status 1 month after RIRS.

Results: After case-control matching, the median age was 49 years (interquartile range [IQR]: 40-58) in Group 1 and 50 years (IQR: 35-60) in Group 2 (p = 0.388). The median stone burden values of Group 1 and Group 2 were 415.3 mm3 (IQR: 176.1-858.2) and 503.3 mm3 (IQR: 282.5-864), respectively (p = 0.100). After RIRS, stone-free status was achieved by 126 of the 159 (79.2%) in Group 1 and 133 of the 159 (83.6%) patients in Group 2 (p = 0.387). The groups were similar in terms of perioperative complications (4.4% in Group 1 and 3.8% in Group 2, p = 0.777), postoperative complications (13.8% in Group 1 and 10.3% in Group 2, p = 0.393), and median operation time (60 min in both, p = 0.230). A longer median fluoroscopy time was noted in Group 1 compared to Group 2 (26 s and 3 s, respectively, p = 0.013).

Conclusions: Stone-free rates and complications were comparable between the patients with lower pole and pelvic stones after RIRS. However, lower pole stones are associated with longer fluoroscopy time. RIRS can be performed effectively for the treatment of lower pole stones.

Urol Int. 2025;109(1):52-60. doi: 10.1159/000541253. Epub 2024 Sep 5. PMID: 39236679