The pelvic anatomic index is an independent predictor for the difficulty of radical prostatectomy

Abstract

Objectives: The aim of the study was to investigate whether a novel simple measurement of pelvic anatomy, the pelvic anatomical index (PAI), which is obtained from simple physical examination, was predictive for potential difficulty and adverse outcome in radical prostatectomy.

Materials and methods: Available data from 73 consecutive radical prostatectomy patients were analyzed. The distances between umbilicus and cranial edge of the symphysis pubis (USPD) and between root of the penis and umbilicus (PUD) were measured. PAI was obtained using the formula (PUD/USPD) × body mass index (BMI). Indicators of surgical difficulty assessed were operation time (OT), dorsal vein bleeding (DVB), total blood loss (TBL), and surgical margin (SM) status. Patients with below-median values of the OT, DVB, TBL, and had negative SM were grouped as favorable surgery (n = 18).

Results: Median OT, DVB, and TBL were 215 (IQR: 187.5-240) min, 380 (IQR: 200-500) cc, and 1000 (IQR: 700-1300) cc, respectively. Both PAI and BMI were significantly correlated with TBL, DVB, and OT (p < 0.05, for all). PAI and BMI significantly associated with favorable surgery (p = 0,006 and p = 0.048, respectively). However, only PAI was an independent predictor of favorable surgery in multivariable logistic regression analysis. A PAI 36 kg/m² was determined as the threshold value for favorable surgery with 83.3% sensitivity and 60% specificity.

Conclusion: PAI significantly correlated with almost all surgical parameters and was a significant independent predictor of favorable surgery. PAI can enable the physician to select and discuss individualized treatment options for patients during preoperative planning.

Keywords: Body mass index; Prostate; Prostatectomy; Robotics.