title: Radiofrequency-assisted laparoscopic partial nephrectomy: clinical and histologic results.
abstract: OBJECTIVE
  To evaluate a surface conductive radiofrequency (RF) coagulation instrument (Tissuelink FB3.0) in laparoscopic and open partial nephrectomy (PN) in hereditary kidney cancer. The lesion depth and viability in the pathologic specimens from a surgical series and an acute porcine model were characterized under conditions of vascular perfusion and occlusion.
  
  
  METHODS
  A total of 19 patients underwent 20 laparoscopic and open procedures with the device. Data were acquired on tumor number, size, operative time, blood loss, length of stay, renal function, complications, pathologic diagnosis, and surgical-margin status. Renal lesions were created in pigs with the device, ultrasonic shears, and a standard electrocautery for specified time intervals and operative energy settings. These lesions were analyzed for depth, diameter, and tissue viability.
  
  
  RESULTS
  In 20 separate (14 laparoscopic; 6 open) procedures in 19 patients, a total of 112 tumors were removed (range 1-31 tumors per procedure). The median operative time, blood loss, and length of stay were 310 minutes, 250 mL, and 4 days, respectively. There were no positive surgical margins. Median preoperative and postoperative creatinine concentrations were similar (1.0 v 1.0 mg/dL). The average treatment margin depth was 3 mm. In the porcine experiments, the treatment depth in the unclamped vascular model was significantly less in than the clamped model (4.0 +/- 1.7 mm v 7.0 +/- 1.6 mm; P < 0.05). Lesion depth and diameter increased with treatment time. Viability depth correlated well with the depth of the visible thermal lesions (Pearson correlation 0.989).
  
  
  CONCLUSIONS
  This RF energy device can provided adequate and uniform hemostatic control without hilar clamping during laparoscopic and open PN for hereditary renal tumors. Gross measures of renal function after surgery appeared clinically unchanged. Coagulation depth is dependent on both tissue perfusion and time in the porcine model.
authors.affiliation: Urologic Oncology Branch, National Institutes of Health, Bethesda, Maryland 20892-1210, USA. colemanj@mail.nih.gov
authors.forename: Jonathan
authors.initials: J
authors.lastname: Coleman
authors.forename: Amar
authors.initials: A
authors.lastname: Singh
authors.forename: Peter
authors.initials: P
authors.lastname: Pinto
authors.forename: John
authors.initials: J
authors.lastname: Phillips
authors.forename: William
authors.initials: W
authors.lastname: Pritchard
authors.forename: Diane
authors.initials: D
authors.lastname: Wray-Cahen
authors.forename: Bradford J
authors.initials: BJ
authors.lastname: Wood
mesh_terms: D000328:Adult; D000818:Animals; D001808:Blood Vessels; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology*; D010535:Laparoscopy / Q000379:methods*; D008875:Middle Aged; D023421:Models, Animal; D009392:Nephrectomy / Q000379:methods*; D011846:Radio Waves; D013525:Surgical Instruments; D013552:Swine; D013997:Time Factors