Login to Access Video or Poster Abstract: MP69-15
Sources of Funding: None

Introduction

Accurate rates of mannitol use for partial nephrectomy (PN) and subsequent intra-operative conversion from PN to radical nephrectomy (RN) are unknown. Understanding factors predictive for conversion and ascertaining surgical outcomes of these converted nephrectomies would contribute greatly to the literature and also allow clinicians to better counsel prospective patients. Thus, we sought to calculate conversion rates of both open and minimally invasive PN using mannitol usage as an indicator for PN intent and to identify factors associated with the conversion from PN to RN.

Methods

A total of 136,298 patients undergoing PN (open: n=68,580, laparoscopic: n=17,549, robotic: n=50,169) and 423,759 undergoing RN (open: n=237,411, laparoscopic: n=143,179, robotic: n=43,169) were identified from the Premier Perspective Database, an all-payer hospital clinical and economic database in the U.S. capturing patients from 2003 to 2015. An algorithm utilizing a variety of charge and billing codes based on the use of mannitol osmotic diuretic in RN was used to calculate rates of conversion.

Results

Overall, mannitol was used in 41.7% of the total PN cohort (open: 32.4%, laparoscopic: 21.7%, robotic: 59.9%, p <0.001). After adjusting for the use of mannitol, the conversion rate of PN to RN was 27.9% for open, 42.6% for laparoscopic, and 14.2% for the robotic approach (p <0.001). Multivariate analysis found that age, gender, charlson comorbidity index, surgical approach, surgery year, and annual surgeon and hospital volume were independent factors associated with conversion from PN to RN (all p<0.001). After adjusting for patient, surgeon and hospital demographics, laparoscopic approach had higher odds (OR=1.77, 95% CI 1.5 to 2.2, p=<0.001) and the robotic-approach had lower odds (OR=0.62, 95% CI 0.54-0.71, p<0.001) of conversion compared to open surgery.

Conclusions

Robot-assisted PN had higher usage rates of mannitol compared to laparoscopic and open approaches. Also, robotic PN had the lowest odds of PN to RN conversion while the laparoscopic approach had the highest odds of conversion. Clinicians should be aware of these conversion rates especially prior to undertaking technically difficult nephron sparing procedures irrespective of approach.

Funding

None