title: Surgical outcomes of percutaneous nephrolithotomy in 3402 patients and results of stone analysis in 1559 patients.
abstract: To report our experience of a series of percutaneous nephrolithotomy (PCNL) procedures in a single centre over 18 years in terms of patient and stone characteristics, indications, stone clearance and complications, along with the results of chemical analysis of stones in a subgroup.
  
  
  
  We retrospectively analysed the outcomes of PCNL in 3402 patients, who underwent the procedure between 1997 and 2014, obtained from a prospectively maintained database. Data analysis included patients' age and sex, laboratory investigations, imaging, punctured calyx, duration of operation, volume of irrigation fluid, radiation exposure time, blood transfusion, complications and stone-free status at 1-month follow-up. For the present analysis, outcomes in relation to complications and success were divided in two eras, 1997-2005 and 2006-2014, to study the differences.
  
  
  
  Of the 3402 patients, 2501 (73.5%) were male and 901 (26.5%) were female, giving a male:female ratio of 2.8:1. Staghorn (partial or complete) calculi were found in 27.5% of patients, while 72.5% had non-staghorn calculi. Intracorporeal energy sources used for stone fragmentation included ultrasonography in 917 patients (26.9%), pneumatic lithoclast in 1820 (53.5%), holmium laser in 141 (4.1%) and Lithoclast®master in 524 (15.4%). In the majority of patients (97.4%) a 18-22-F nephrostomy tube was placed after the procedure, while 69 patients (2.03%) underwent tubeless PCNL. The volume of the irrigation fluid used ranged from 7 to 37 L, with a mean of 28.4 L. The stone-free rate after PCNL in the first era studied was 78%, vs 83.2% in the second era, as assessed by combination of ultrasonography and plain abdominal film of the kidney, ureter and bladder. The complication rate in the first era was 21.3% as compared with 10.3% in the second era, and this difference was statistically significant. Stone analysis showed pure stones in 41% and mixed stones in 58% of patients. The majority of stones consisted of calcium oxalate.
  
  
  
  This is the largest series of PCNL reported from any single centre in Pakistan, where there is a high prevalence of stone disease associated with infective and obstructive complications, including renal failure. PCNL as a treatment method offers an economic and effective option in the management of renal stone disease with acceptable stone clearance rates in a resource-constrained healthcare system.
authors.affiliation: Department of Urology, Sindh Institute of Urology and Transplantation, Civil Hospital, Karachi, Pakistan.
authors.forename: Syed Adibul Hasan
authors.initials: SAH
authors.lastname: Rizvi
authors.affiliation: Department of Urology, Sindh Institute of Urology and Transplantation, Civil Hospital, Karachi, Pakistan.
authors.forename: Manzoor
authors.initials: M
authors.lastname: Hussain
authors.affiliation: Department of Urology, Sindh Institute of Urology and Transplantation, Civil Hospital, Karachi, Pakistan.
authors.forename: Syed Hassan
authors.initials: SH
authors.lastname: Askari
authors.affiliation: Department of Urology, Sindh Institute of Urology and Transplantation, Civil Hospital, Karachi, Pakistan.
authors.forename: Altaf
authors.initials: A
authors.lastname: Hashmi
authors.affiliation: Department of Urology, Sindh Institute of Urology and Transplantation, Civil Hospital, Karachi, Pakistan.
authors.forename: Murli
authors.initials: M
authors.lastname: Lal
authors.affiliation: Department of Pathology, Sindh Institute of Urology and Transplantation, Civil Hospital, Karachi, Pakistan.
authors.forename: Mirza Naqi
authors.initials: MN
authors.lastname: Zafar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry / Q000453:epidemiology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000009:adverse effects / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000453:epidemiology; D012189:Retrospective Studies; D055815:Young Adult
keywords: #KidneyStones; #UroStone; PCNL; renal stones; staghorn stones