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Background: Benefits of minimally invasive partial nephrectomy (MIPN) compared to open partial nephrectomy (OPN) include reduced narcotic requirements, shorter hospital stay, and faster convalescence. Some comparative studies suggest that this comes at the price of higher perioperative bleeding risk for MIPN, which may no longer be the case as techniques have evolved. Using a national database, we sought to compare 30 day complication rates between OPN and MIPN.
Methods: Utilizing the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) data file, patients undergoing OPN or MIPN between January 2007 and December 2010 were identified using Current Procedural Terminology (CPT) codes 50240 and 50543, respectively. NSQIP is an outcomes-based database measuring surgical quality of care. Preoperative and intraoperative variables, as well as 30-day perioperative complications, were collected and analyzed.
Results: A total of 1,243 patients were identified who underwent OPN (n=718, 58%) or MIPN (n=525, 42%). The percentage of MIPN increased from 14% in 2007 to 45% in 2010. Pre-operative patient characteristics were similar between the two groups (Table 1). Operative time was significantly longer with MIPN (185.5 vs. 209.7 mins, p<0.001). Hospital stay was shorter following MIPN (5.4 vs. 3.2 days, p<0.001). Postoperatively, the OPN cohort had significantly more superficial wound infections, organ space infections, urinary tract infections, and bleeding events requiring transfusion (Table 2).
Conclusions: The number of partial nephrectomies being performed using minimally invasive techniques (laparoscopic or robotic) is increasing. We acknowledge the limitations of this dataset as we are unable to evaluate nephrometry scores or tumor characteristics. However, in this large national database, MIPN was associated with longer operative times, but shorter hospital stay. OPN was associated with more wound complications, urinary tract infections, and post-operative transfusions.

Table.1. Demographics and pre-operative risk factors of patients undergoing OPN and MIPN
	OPN n=718	MIPN n=525	p-value
Male, no. (%)	441 (61)	306 (58)	0.26
Age, yrs (mean)	58.6	59.8	0.101
BMI (mean)	30.4	30.3	0.752
Pre-operative creatinine, mg/dL	1.07	1.01	0.141
Bleeding disorder, no. (%)	15 (2.1)	8 (1.5)	0.465
Diabetes, no. (%)	152 (20.1)	89 (17)	0.063
Smoker, no. (%)	150 (21.2)	99 (19)	0.376
Chronic obstructive pulmonary disease, no. (%)	32 (4.5)	17 (3.2)	0.275
Dialysis dependent, no. (%)	8 (1.1)	4 (0.8)	0.53
Peripheral vascular disease, no. (%)	7 (1)	5 (0.9)	0.692
Hypertension, no. (%)	447 (62)	309 (59)	0.225
History of myocardial infarction, no. (%)	2 (0.3)	0 (0)	0.512
History of stroke, no. (%)	22 (3.1)	10 1.9)	0.204
Operative time, mins (mean)	185.5	209.7	<0.001
Length of hospitalization, days (mean)	5.4	3.2	<0.001

Table 2. 30-day outcomes of patients undergoing OPN and MIPN
Complication, no. (%)	OPN n=718	MIPN n=525	p-value
Superficial wound infection	10 (1.4)	1 (.2)	0.03
Deep wound infection	4 (0.6)	1 (.2)	0.404
Organ space infection	12 (1.7)	2 (0.4)	0.033
Wound dehiscence	3 (0.4)	3 (0.6)	0.7
Urinary tract infection	22 (3.1)	7 (1.3)	0.046
Deep vein thrombosis	3 (0.4)	7 (1.3)	0.106
Bleeding requiring transfusion	41 (5.7)	12 (2.2)	0.003
Pneumonia	6 (0.8)	5 (1)	1
Pulmonary embolism	6 (0.8)	5 (1)	1
Re-intubation	7 (0.9)	2 (0.4)	0.317
Acute renal failure	13 (1.8)	3 (0.6)	0.056
Stroke	3 (0.4)	0 (0)	0.267
Cardiac arrest	5 (0.7)	2 (0.28)	0.706
Sepsis/septic shock	21 (2.9)	7 (0.96)	0.062
Return to operating room	22 (3.1)	12 (1.65)	0.406

Disclosure: The American College of Surgeons National Surgical Quality Improvement Program and the hospitals participating in the ACS NSQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.