title: Haemostatic partial nephrectomy using bipolar radiofrequency ablation.
abstract: OBJECTIVE
  To determine whether an electrode array with a bipolar radiofrequency ablation (RFA) energy source can be used to perform a haemostatic partial nephrectomy by simultaneously ablating and coagulating renal tissue.
  
  
  METHODS
  Lower-pole partial nephrectomy was performed in 12 porcine kidneys using a bipolar RFA system. Intraoperative ultrasonography was used to identify and avoid the collecting system. Tissues were positioned between opposing electrodes and tissue impedance monitored using a proprietary feedback and control algorithm. Ablation time and power, lesion width and length, and tissue thickness were recorded. The kidneys were assessed in vivo to show haemostasis of the remaining renal unit. Collecting system integrity was assessed with methylene blue injection, and the resected tissue analysed histologically.
  
  
  RESULTS
  Partial nephrectomies were successful in all 12 porcine kidneys; the mean nephrectomy specimen was 3.2 x 2.6 cm. The total ablation time (sem) per lesion was 211 (15) s and the mean power was 23 W. Methylene blue injection showed an intact collecting system in 11 of the 12 kidneys, and haematoxylin and eosin staining showed a mean zone of necrosis of 9 mm at the resection margin. Ultrasonography revealed flow to the remaining kidneys after RFA and the in vivo assessment of haemostasis revealed no abnormal bleeding or haemorrhage from the kidneys.
  
  
  CONCLUSIONS
  Applying bipolar RF energy to an electrode array can enable transmural excision of renal parenchyma in vivo in a bloodless fashion without collecting system injury.
authors.affiliation: Department of Surgery/Division of Urology, University of Wisconsin Medical School, 600 Highland Avenue, Madison, WI 53792, USA. gypmd@aol.com
authors.forename: Gyan
authors.initials: G
authors.lastname: Pareek
authors.forename: Eric R
authors.initials: ER
authors.lastname: Wilkinson
authors.forename: David
authors.initials: D
authors.lastname: Schutt
authors.forename: James A
authors.initials: JA
authors.lastname: Will
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Warner
authors.forename: Dieter
authors.initials: D
authors.lastname: Haemmerich
authors.forename: David
authors.initials: D
authors.lastname: Mahvi
authors.forename: Stephen Y
authors.initials: SY
authors.lastname: Nakada
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D006488:Hemostasis, Surgical; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology; D023421:Models, Animal; D009392:Nephrectomy / Q000379:methods*; D011184:Postoperative Period; D012039:Regional Blood Flow; D013552:Swine; D014463:Ultrasonography