title: Percutaneous nephrolithotomy; alarming variables for postoperative bleeding.
abstract: OBJECTIVE
  To evaluate factors contributing to bleeding after percutaneous nephrolithotomy (PCNL) and ways of managing this complication, as bleeding is a serious sequela that requires prompt management.
  
  
  METHODS
  The demographic and procedural data of 200 patients, who underwent unilateral PCNL during a 20-month period, were prospectively collected. Preoperative, operative, and postoperative details were recorded. The preoperative variables analysed included: age, sex, body mass index (BMI), the presence of hypertension, diabetes mellitus, serum creatinine, degree of hydronephrosis, previous ipsilateral open renal surgery, stone size and complexity. The operative variables analysed included: number of tracts, operative time, size of Amplatz sheath, type of anaesthesia, and complications such as calyceal and pelvic perforation.
  
  
  RESULTS
  The variables of age, sex, BMI, diabetes, hypertension, and a preoperative creatinine level of >1.4 mg/dL had no significant effect on blood loss (allP> 0.05). However, the rate of bleeding was significantly higher (P⩽ 0.05) in patients who had a history of previous open renal surgery, intraoperative pelvicalyceal perforations, and Guy's Stone Score (GSS) grade 3 and 4 complex stones; however, absence of hydronephrosis, larger stone size, operative time (>83 min), more than one puncture, and size of the Amplatz sheath (26-30 F) did not maintain their significance in multivariate analysis.
  
  
  CONCLUSIONS
  According to our present results stone complexity (GSS grade 3 and 4), history of ipsilateral renal stone surgery, and occurrence of intraoperative pelvicalyceal perforation are alarming variables for post-PCNL bleeding.
authors.affiliation: Department of Urology, Sulaymaniyah Surgical Teaching Hospital, Sulaymaniyah, Iraq.
authors.forename: Shakhawan H A
authors.initials: SH
authors.lastname: Said
authors.affiliation: Department of Urology, Sulaymaniyah Surgical Teaching Hospital, Sulaymaniyah, Iraq.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Al Kadum Hassan
authors.affiliation: Department of Urology, Sulaymaniyah Surgical Teaching Hospital, Sulaymaniyah, Iraq.
authors.forename: Rawa H G
authors.initials: RH
authors.lastname: Ali
authors.affiliation: Department of Surgery, University of Sulaymaniyah, Faculty of Medical Sciences, School of Medicine, Iraq.
authors.forename: Ismaeel
authors.initials: I
authors.lastname: Aghaways
authors.affiliation: Department of Cardiothoracic Surgery, Sulaymaniyah Surgical Teaching Hospital, Sulaymaniyah, Iraq.
authors.forename: Fahmi H
authors.initials: FH
authors.lastname: Kakamad
authors.affiliation: Department of Urology, Rizgari Teaching Hospital, Erbil, Iraq.
authors.forename: Khalid Q
authors.initials: KQ
authors.lastname: Mohammad
keywords: BMI, body mass index; Bleeding; Complications; GSS, Guy’s Stone Score; Hb, haemoglobin; KUB, plain abdominal radiograph of the kidneys, ureters and bladder; OR, odds ratio; PCNL, percutaneous nephrolithotomy; Percutaneous nephrolithotomy; Renal stones; US, ultrasonography