Analysis of Needle Placement Error During Prostate Biopsies in Real Clinical Cases: Effects of Needle Tip Orientation and Target Location.

The transperineal approach in prostate interventions is increasingly favored for its lower infection risk and enhanced targeting accuracy. However, its precision can be affected by factors such as needle deflection, prostate deformation, and operator variability. Numerous studies have proposed models of needle deflection based on needle tip orientation. However, we hypothesize that anatomical location of the prostate cancer has a more significant influence on the direction of needle deflection than the needle tip orientation of clinically available needles. To test the hypothesis, we analyzed data from 231 in-vivo, transperineal, robot-assisted MRI-guided prostate biopsies using a mixed-effects logistic regression model to examine the association between needle tip orientation, the anatomical location of the prostate target and the resulting direction of needle deflection. The analysis shows that the needle tip orientation is not a significant predictor of needle deviation direction, while the anatomical location of the prostate targeted during each insertion appeared as a significant predictor of deflection direction (p < 0.001, OR = 10.89). We conclude that the anatomical location is a key determinant of needle deflection, while needle tip orientation has minimal impact. These results provide critical insights into the mechanics of needle-tissue interaction, potentially informing strategies to improve targeting accuracy in transperineal prostate interventions.