Histological evaluation of tissue damage caused by rotational needle insertion.

Needles used in percutaneous insertion must be as thin as possible to minimize invasiveness. However, using extra-thin needles with a diameter less than 25G (0.53 mm diameter) can cause needle deflection. Needle deflection can be minimized by insertion with axial rotation along the needle shaft; this rotation is also useful for steering the insertion direction of the needle tip. However, although high rotation speeds may decrease needle deflection, this may increase tissue damage. Therefore, the purpose of this study was to histologically evaluate tissue damage caused by the rotational needle-insertion method, and to verify the needle-tip deflection caused by tissue damage. In this paper, we evaluated tissue damage and needle deflection caused by needle insertion with no rotation, unidirectional rotation, and bidirectional rotation. The results suggest that percutaneous needle insertion under unidirectional rotation is potentially risky in humans, as this causes wound-up tissue and expansion of the area of the hole created by the needle path. In contrast, needle insertion under bidirectional rotation appeared to minimize deflection, and prevented winding of tissue and expansion of the hole created by the needle path.