Predicting new-baseline glomerular filtration rate (NBGFR) after donor nephrectomy: validation of a split renal function (SRF)-based formula.

BACKGROUND: Accurate prediction of post-donor nephrectomy (DN) glomerular filtration rate is potentially useful for evaluating and counselling living kidney donors. Currently, there are limited tools to evaluate post-operative new-baseline glomerular filtration rate (NBGFR) in kidney donors. We aim to validate a conceptually simple formula based on split renal function (SRF) previously developed for radical nephrectomy patients. METHODS: Eighty-three consecutive patients who underwent DN from 2010 to 2016 were included. Pre-operative CT imaging and functional data including pre-DN baseline Global GFR (108.2 ± 13.2 mL/min/1.73m2) were included. Observed NBGFR was defined as the latest eGFR 3-12 months post-DN. SRF, defined as volume of the contralateral non-resected kidney normalised by total volume of kidneys, was determined from pre-operative cross-sectional imaging (49.2 ± 2.36%). The equation derived from Rathi et al. is as detailed: Predicted NBGFR = 1.24 × (Global GFR Pre-DN) x (SRF). RESULTS: The relationship between predicted NBGFR (66.0 ± 8.29 mL/min/1.73m2) and observed NBGFR (74.9 ± 16.4 mL/min/1.73m2) was assessed by evaluating correlation coefficients, bias, precision, accuracy, and concordance. The new SRF-based formula for NBGFR prediction correlated strongly with observed post-operative NBGFR (Pearson's r = 0.729) demonstrating minimal bias (median difference = 7.190 mL/min/1.73m2) with good accuracy (96.4% within ± 30%, 62.7% within ± 15%) and precision (IQR of bias = - 0.094 to 16.227). CONCLUSION: The SRF-based formula was also able to accurately discriminate all but one patient to an NBGFR of > 45 mL/min/1.73m2. We utilised the newly developed SRF-based formula for predicting NBGFR in a living kidney donor population. Counselling of donor post-operative renal outcomes may then be optimised pre-operatively.

Performance in the Fundamentals of Laparoscopic Surgery: Does it reflect global rating scales in the Objective Structured Assessment of Technical Skills in porcine laparoscopic surgery?

Objective: To correlate the utility of the Fundamentals of Laparoscopic Surgery (FLS) manual skills program with the Objective Structured Assessment of Technical Skills (OSATS) global rating scale in evaluating operative performance. Methods: The Asian Urological Surgery Training and Educational Group (AUSTEG) Laparoscopic Upper Tract Surgery Course implemented and validated the FLS program for its usage in laparoscopic surgical training. Delegates' basic laparoscopic skills were assessed using three different training models (peg transfer, precision cutting, and intra-corporeal suturing). They also performed live porcine laparoscopic surgery at the same workshop. Live surgery skills were assessed by blinded faculty using the OSATS rating scale. Results: From March 2016 to March 2019, a total of 81 certified urologists participated in the course, with a median of 5 years of post-residency experience. Although differences in task time did not reach statistical significance, those with more surgical experience were visibly faster at completing the peg transfer and intra-corporeal suturing FLS tasks. However, they took longer to complete the precision cutting task than participants with less experience. Overall OSATS scores correlated weakly with all three FLS tasks (peg transfer time: r=-0.331, r 2=0.110; precision cutting time: r=-0.240, r 2=0.058; suturing with intra-corporeal knot time: r=-0.451, r 2=0.203). Conclusion: FLS task parameters did not correlate strongly with OSATS globing rating scale performance. Although FLS task models demonstrated strong validity, it is important to assimilate the inconsistencies when benchmarking technical proficiency against real-life operative competence, as evaluated by FLS and OSATS, respectively.