Method and apparatus for adjusting the length of a combined spinal-epidural needle

摘要

Regulating the extension length of a spinal needle (12) relative to an epidural needle (14) comprises using a tube (51) which slides on an inner tube (32), each tube being fixed to one of the needles. The inner tube has an axially extending slot (36) providing access to a structured interior surface (38) of concentric groove elements (38a), while the outer tube has an outside surface (53) e.g. forming a hexagon. Contact points are established by the intersection of the rounded outside surface of the inner tube and the planar surfaces (58) inside the outer tube. An actuating tab (50) formed on the outer tube forms a selectable fixed connection between the tubes to lock them.