title: Technique and outcomes of robot-assisted retroperitoneoscopic partial nephrectomy: a multicenter study.
abstract: BACKGROUND
  Robot-assisted retroperitoneoscopic partial nephrectomy (RARPN) may be used for posterior renal masses or with prior abdominal surgery; however, there is relatively less familiarity with RARPN.
  
  
  OBJECTIVE
  To demonstrate RARPN technique and outcomes.
  
  
  METHODS
  A retrospective multicenter study of 227 consecutive RARPNs was performed at the Swedish Medical Center, the University of Michigan, and the University of California, Los Angeles, from 2006 to 2013.
  
  
  METHODS
  RARPN.
  
  
  METHODS
  We assessed positive margins and cancer recurrence. Stepwise regression was used to examine factors associated with complications, estimated blood loss (EBL), warm ischemia time (WIT), operative time (OT), and length of stay (LOS).
  
  
  CONCLUSIONS
  The median age was 60 yr (interquartile range [IQR]: 52-66), and the median body mass index (BMI) was 28.2 kg/m(2) (IQR: 25.6-32.6). Median maximum tumor diameter was 2.3 cm (IQR: 1.7-3.1). Median OT and WIT were 165 min (IQR: 134-200) and 19 min (IQR: 16-24), respectively; median EBL was 75 ml (IQR: 50-150), and median LOS was 2 d (IQR: 1-3). Twenty-eight subjects (12.3%) experienced complications, three (1.3%) had urine leaks, and three (1.3%) had pseudoaneurysms that required reintervention. There was one conversion to radical nephrectomy and three transfusions. Overall, 143 clear cell carcinomas (62.6%) composed most of the histology with eight positive margins (3.5%) and two recurrences (0.9%) with a median follow-up of 2.7 yr. In adjusted analyses, intersurgeon variation was associated with complications (odds ratio [OR]: 3.66; 95% confidence interval, 1.31-10.27; p = 0.014) and WIT (parameter estimate [PE; plus or minus standard error]: 4.84 ± 2.14; p = 0.025). Higher surgeon volume was associated with shorter WIT (PE: -0.06 ± 0.02; p = 0.002). Higher BMI was associated with longer OT (PE: 2.09 ± 0.56; p < 0.001). Longer OT was associated with longer LOS (PE: 0.01 ± 0.01; p = 0.002). Finally, there was a trend for intersurgeon variation in OT (PE: 18.5 ± 10.3; p = 0.075).
  
  
  CONCLUSIONS
  RARPN has acceptable morbidity and oncologic outcomes, despite intersurgeon variation in WIT and complications. Greater experience is associated with shorter WIT.
  
  
  RESULTS
  Robot-assisted retroperitoneoscopic partial nephrectomy has acceptable morbidity and oncologic outcomes, and there is intersurgeon variation in warm ischemia time and complications.
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. Electronic address: jchu@mednet.ucla.edu.
authors.forename: Jim C
authors.initials: JC
authors.lastname: Hu
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Treat
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Filson
authors.affiliation: Department of Urology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: McLaren
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Siwei
authors.initials: S
authors.lastname: Xiong
authors.affiliation: Swedish Medical Center, Seattle, WA, USA.
authors.forename: Sevan
authors.initials: S
authors.lastname: Stepanian
authors.affiliation: Department of Urology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Khaled S
authors.initials: KS
authors.lastname: Hafez
authors.affiliation: Department of Urology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Alon Z
authors.initials: AZ
authors.lastname: Weizer
authors.affiliation: Swedish Medical Center, Seattle, WA, USA.
authors.forename: James
authors.initials: J
authors.lastname: Porter
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical; D015992:Body Mass Index; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D002983:Clinical Competence; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D010535:Laparoscopy / Q000009:adverse effects / Q000379:methods*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000209:etiology*; D018365:Neoplasm, Residual; D009392:Nephrectomy / Q000009:adverse effects / Q000379:methods*; D061646:Operative Time; D012187:Retroperitoneal Space; D012189:Retrospective Studies; D065287:Robotic Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome; D052096:Warm Ischemia
keywords: Outcomes; Partial nephrectomy; Renal cell carcinoma; Retroperitoneal approach; Robotic surgery