title: Robotic Partial Nephrectomy for Posterior Tumors Through a Retroperitoneal Approach Offers Decreased Length of Stay Compared with the Transperitoneal Approach: A Propensity-Matched Analysis.
abstract: We sought to compare surgical outcomes between transperitoneal and retroperitoneal robotic partial nephrectomy (RPN) for posterior tumors.
  
  
  
  Using our multi-institutional RPN database, we reviewed 610 consecutive cases for posterior renal masses treated between 2007 and 2015. Primary outcomes were complications, operative time, length of stay (LOS), surgical margin status, and estimated glomerular filtration rate (eGFR) preservation. Secondary outcomes were estimated blood loss, warm ischemia time (WIT), disease recurrence, and disease-specific mortality. Due to significant differences in treatment year and tumor size between approaches, retroperitoneal cases were matched 1:4 to transperitoneal cases based on propensity scores using the greedy algorithm. Outcomes were compared between approaches using the chi-square and Mann-Whitney U tests.
  
  
  
  After matching, 296 transperitoneal and 74 retroperitoneal cases were available for analysis, and matched groups were well balanced in terms of treatment year, age, gender, race, American Society of Anesthesiologists physical status classification (ASA) score, body mass index, tumor laterality, tumor size, R.E.N.A.L. (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus, anterior/posterior, location relative to polar lines) score, and hilar location. Compared with transperitoneal, the retroperitoneal approach was associated with significantly shorter mean LOS (2.2 vs 2.6 days, p = 0.01), but longer mean WIT (21 vs 19 minutes, p = 0.01). Intraoperative (p = 0.35) and postoperative complications (p = 0.65), operative time (p = 0.93), positive margins (p = 1.0), and latest eGFR preservation (p = 0.25) were not significantly different between approaches. No differences were detected in the other outcomes.
  
  
  
  Among high-volume surgeons, transperitoneal and retroperitoneal RPN achieved similar outcomes for posterior renal masses, although with slight differences in LOS and WIT. Retroperitoneal RPN may be an effective option for the treatment of certain small posterior renal masses.
authors.affiliation: 1 Department of Urology, Glickman Urological and Kidney Institute , Cleveland Clinic, Cleveland, Ohio.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Maurice
authors.affiliation: 1 Department of Urology, Glickman Urological and Kidney Institute , Cleveland Clinic, Cleveland, Ohio.
authors.forename: Jihad H
authors.initials: JH
authors.lastname: Kaouk
authors.affiliation: 1 Department of Urology, Glickman Urological and Kidney Institute , Cleveland Clinic, Cleveland, Ohio.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ramirez
authors.affiliation: 2 Division of Urology, Washington University School of Medicine , St. Louis, Missouri.
authors.forename: Sam B
authors.initials: SB
authors.lastname: Bhayani
authors.affiliation: 3 James Buchanan Brady Urological Institute , Johns Hopkins Medical Institutions, Baltimore, Maryland.
authors.forename: Mohamad E
authors.initials: ME
authors.lastname: Allaf
authors.affiliation: 4 Vattikuti Urology Institute , Henry Ford Hospital, Detroit, Michigan.
authors.forename: Craig G
authors.initials: CG
authors.lastname: Rogers
authors.affiliation: 5 Department of Urology, Hackensack University Medical Center , Hackensack, New Jersey.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Stifelman
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000401:mortality / Q000601:surgery*; D007902:Length of Stay / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000601:surgery; D009392:Nephrectomy / Q000379:methods*; D061646:Operative Time; D011183:Postoperative Complications / Q000601:surgery; D057216:Propensity Score; D012187:Retroperitoneal Space / Q000601:surgery*; D065287:Robotic Surgical Procedures / Q000379:methods*; D016896:Treatment Outcome; D052096:Warm Ischemia
keywords: laparoscopic approach; renal cancer; robotics