Nominal logistic regression analysis of variables determining needle visibility in ultrasound images - a full factorial cadaver study.

Background: Needle visualization is essential to avoid vascular puncture and nerve injury in ultrasound-guided regional anesthesia. Several factors that statistically influence needle visibility have been described but the dimensions of their individual impact remain unclear. This study aimed to quantify the impact of various independent factors on ultrasound needle visibility.

Perineural hematoma may result in nerve inflammation and myelin damage.

Background And Objectives: Perineural hematoma may occur during performance of peripheral nerve blocks. The aim of this study was to test the hypothesis that an iatrogenic hematoma in the immediate vicinity of a peripheral nerve may cause histologic evidence of nerve injury.

Methods: Fifty milliliters of autologous blood was injected adjacent to the right sciatic nerve in 20 anesthetized female pigs.