Ultrasonographic evaluation demonstrating safer needle-organ distances in a novel quadratus lumborum block technique in cats.

Introduction: We investigated the relationship between needle placement and adjacent organs using ultrasonography during a novel quadratus lumborum block (QLB) performed in sternal recumbency and the conventional QLB performed in lateral recumbency among cats undergoing elective ovariohysterectomy. Methods: Fourteen client-owned female cats were randomly allocated to the conventional QLB group ( Results: Compared with the conventional QLB group, the novel QLB group had fewer organs within 5 mm of the needle shaft on the right side. The novel QLB group also showed greater distances from the needle shaft and entry point to the nearest organs, as well as a shorter distance from the needle tip to the nearest organ. In tilted images, no between-group differences were identified except at 100° on the left side, where the novel QLB group had a longer distance. Blood vessels were the structures most frequently identified near the needle pathway. Discussion: The novel QLB positioned the needle trajectory farther from vital organs, particularly on the right side, supporting its potential safety advantage. Real-time ultrasonographic visualization remains necessary because organs were still identified parallel to the trajectory or distal to the needle tip.