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Background: Nephron sparing surgery is the standard of care for surgically amenable renal masses. In addition, in the last decade, laparoscopic and robotic partial nephrectomy has become an increasingly larger component of surgical therapy. The purpose of this study is to compare perioperative outcomes of open vs. laparoscopic/robotic partial nephrectomy using the R.E.N.A.L. nephrometry scoring system to standardize tumor complexity.
Methods: A retrospective analysis of perioperative outcomes was performed on a prospectively collected database of patients from March 2003 to May 2012 who underwent laparoscopic, robotic, or open partial nephrectomy for renal lesions. The R.E.N.A.L. nephrometry scoring system was used to group the patients into low, moderate, and high complexity cohorts.
Results: A total of 838 patients underwent partial nephrectomy for renal lesions during the study time period. 338 patients were excluded for multiple lesions, lack of available imaging (inability to score with nephrometry), solitary kidneys, and inadequate follow-up. Of the 500 remaining patients, 376 (75%) patients underwent open partial nephrectomy and 124 (25%) underwent laparoscopic or robotic partial nephrectomy. A subset analysis was performed by grouping lesions into low (4-6), moderate (7-8), and high (9-12) complexity cohorts using R.E.N.A.L. nephrometry scoring in order to more accurately compare lesion tumor complexity. Across the entire study population, there was no difference in age, gender, race, BMI, pathological T stage, margin positivity, long term change in eGFR, recurrence, or death. The laparoscopic/robotic cohort showed an advantage in terms of blood loss (211cc vs. 696cc), length of hospital stay (3.2 vs. 5.6 days), Clavien grade 1 (17% vs. 37%) and 2 (15% vs. 27%) complications, and urine leaks (2.4% vs. 8.8%). The open cohort revealed a significantly smaller change in short term eGFR (1.6% vs. 5.9%), duration of surgery (216 min vs. 247 min), and renal artery clamping time (20 min vs. 26.2min). The open cohort also had larger mean preoperative Charlson comorbidity indices (2.0 vs. 1.2), ASA scores, tumor sizes (3.5cm vs. 2.5cm), and nephrometry scores (7.8 vs. 6.0). On subset analysis, the vast majority of patients with highly complex lesions were treated using the open technique (139 open vs. 10 laparoscopic/robotic) with the only significant difference being blood loss (899cc vs. 217cc) in favor of the laparoscopic/ robotic approach.
Conclusions: The minimally invasive (laparoscopic/robotic) approach to partial nephrectomy showed similar perioperative outcomes with the advantages of decreased blood loss, shorter hospital stay, and fewer minor complications. Among patients with higher complexity lesions (as indicated by nephrometry scores ≥9), as well as patients with greater comorbidities prior to their surgery (as indicated by ASA and Charlson comorbidity scores), there was a bias towards the open approach. This indicates a perceived advantage of the open approach in highly complex patients. It is suggested that these complex patients be evaluated in a tertiary care setting for consideration of the open approach or minimally invasive technique.