The Clinical Value Of Diameter–axial–polar Nephrometry Score In Nephron-sparing Surgery And The Research On Its Intra-observer And Inter-observer Reliability

Objective To evaluate the clinical value of the DAP nephrometry scoring system on surgical outcomes following nephron-sparing surgery and the intra-observer and inter-observer reliability of diameter–axial–polar nephrometry score.Methods This was a retrospective study of 110 patients who underwent open,laparoscopic,or robotic-assisted partial nephrectomy for renal tumors at our hospital.We preoperative analyzed the clinical and radiological data.Computed tomography images were respectively scored and categorized them as low-score,moderate-score,and high-score groups according to tumor complexity.Statistical analysis was performed to determine the relationship between surgical approaches,perioperative outcomes and DAP score.Also,the imaging data of these patients were collected and independently scored by 5 urologists(2 attendings and 3 residents).The two residents of these observers were each assigned for a second time three months later.We evaluated intra-observer and inter-observer agreement by Kappa test and Kendall tau-b test,respectively.The variability among all observers with different levels of experience was assessed by intraclass correlation coefficients.Results Totally 18 cases in open group,62 cases in laparoscopic group,and 30 patients in robotic group were included in this study.Among them,54 were male patients and 56 were female patients.Their average age was(50.9±12.2)years old.The mean body mass index was(23.4±3.3)kg/m2 and the mean ASA score was(1.4±0.5).Tumor was located at left in 55 cases and right 55 cases,and each of these tumors was solitary one.The DAP sum score exhibited a statistically significant association with surgical procedures,operative time,ischemia time,and estimated blood loss,while found no correlation with the hospital day and the change rate of estimated glomerular filtration rate.The intra-observer agreement of all component scores and sum score indicated by Kappa test were 0.889,0.817,0.787,and 0.693(0.897,0.834,0.830,and 0.708 for the other resident).The inter-observer agreement of all component scores and sum score indicated by Kendall tau-b test were 0.896,0.832,0.847,and 0.832,respectively.On the Bland-Altman graph,more than 90% of the sites for each DAP components were located in the 95% confidence interval within the reference line.The agreement between more clinically experienced surgeons was higher than juniors.Conclusion DAP is associated with some of the significant surgical results and can be useful for making surgical decisions.The diameter–axial–polar system is a reliability and repeatability tool with adequate agreement among different observers and by the same observers.