title: Comparison of complication rates for unilateral and bilateral percutaneous nephrolithotomy (PCNL) using a modified Clavien grading system.
abstract: OBJECTIVE
  To compare complication rates of unilateral vs bilateral percutaneous nephrolithotomy (PCNL) using the modified Clavien grading system.
  
  
  METHODS
  Single-institution retrospective chart review. Identified patients who had synchronous bilateral PCNL (B-PCNL) over an 11-year period (2000-2011). B-PCNL patients were matched by age, gender, and stone burden per renal unit with patients who underwent unilateral PCNL (U-PCNL) over the same period. Complications were recorded and classified using the modified Clavien classification system, and then compared with a two-sided chi-square test of proportions.
  
  
  RESULTS
  In all, 47 B-PCNL patients [mean (range) age 54 (14-84) years] and 78 U-PCNL patients [mean (range) age 54 (17-91 years] were compared. The mean (range) stone burden per renal unit was 2.8 (0.7-7.0) cm and 2.9 (0.7-9.0) cm, respectively. The overall complication rate was higher for B-PCNL (53.2% vs 30.8%, P = 0.013). Rates of Grade I and Grade II complications trended toward being higher in the B-PCNL group. Low-grade complications (Grade I and II combined) occurred more often in the B-PCNL group (P = 0.011); the most common low-grade complication was fever. Two procedures terminated for poor visualisation due to bleeding were successfully completed in delayed fashion with no transfusion and were classified as Grade I complications. There were equivalently low rates of Grade III complications. There were no Grade IV or V complications.
  
  
  CONCLUSIONS
  B-PCNL carries a higher overall complication rate than U-PCNL when the modified Clavien system is used for classification. Patients undergoing U-PCNL who have more than one tract dilatation have a higher complication rate than those who have only one tract dilatation. High-grade complications are uncommon for both procedures.
authors.affiliation: Department of Urology, Loyola University Medical Center, Maywood, IL 60153, USA. akadlec@lumc.edu
authors.forename: Adam O
authors.initials: AO
authors.lastname: Kadlec
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Greco
authors.forename: Zachary C
authors.initials: ZC
authors.lastname: Fridirici
authors.forename: Spencer T
authors.initials: ST
authors.lastname: Hart
authors.forename: Ted G
authors.initials: TG
authors.lastname: Vellos
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Turk
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000009:adverse effects* / Q000379:methods; D011183:Postoperative Complications / Q000145:classification* / Q000175:diagnosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult