Analysis of the Clinical Efficacy and Safety of Percutaneous Nephrolithotomy in Patients with Anatomical Variations: A Single Center Retrospective Study

Abstract

Introduction and Objective: Percutaneous Nephrolithotomy (PCNL) is the standard of care for renal stones >2cm. Kidneys with anatomical disparities resulting from fusion (horseshoe), malrotation, ectopic location (allografts) and bifid collecting systems present as a challenge because variations in vasculature, calyceal rotation and intervening viscera may make percutaneous access treacherous. Reported here is the authors’ experience with PCNL in these types of kidneys.

Methods: A chart review was done on all patients who underwent PCNL at the National Kidney and Transplant Institute (NKTI) from 2012-2016. Those with anatomical variations were identified and analyzed. Patient demographics (age, gender, co-morbidity) and stone characteristics (Guy’s stone score, laterality) were summarized. Intraoperative parameters such as location of puncture site (upper, mid, inferior calyces), number of tracts (single vs. multiple), operative time, estimated blood loss (EBL), and length of hospital stay (LOS) were analyzed. The primary endpoints were stone-free and complication rates according to the Clavien-Dindo (CD) classification.

Results: A total of 1,657 PCNLs were performed during the study period, of which 42 had anatomical variants. The mean age was 45.2±8.8 (R= 28-65) with a male to female ratio of 3:1. There were 18 horseshoe (42.9%), 15 bifid (35.7%), 7 malrotated (16.7%) and 2 renal allografts (4.8%.); Laterality- wise, 28 (67%) were left-sided, 12 (29%) were right-sided and 2 (5%) had right-sided pelvic kidneys (allografts). The Guy stone scores were 3 and 4 in 13 (30%) and 29 (70%) patients, respectively. The mean stone diameter was 3.8±0.6 cms. (R=2.5-5.5). Majority, n=37 (88%) were treated with an upper pole access. Thirty-six (86%) needed a single tract and while six (14%) required multiple tracts (bifid pelvis). The mean operative time was 111.5±28.1 mins. (R=65-188), EBL was 461±278.4 cc (R=200-1300). LOS was 3.6±0.94 days (R=2-7). The stone-free rate was 95%. Twenty-five (59.5%) complications were documented. Fifteen (35.7%) had fever: Grade I CD, and 10 (23.8%) required transfusion: Grade II CD. There was no mortality.

Conclusion: PCNL still persists as the treatment of choice for nephrolithiasis in kidneys with variations in anatomy or position. A high stone clearance rate can be achieved while minimizing complications.