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The effect of introducer gauge, design and bevel direction on the deflection of spinal needles *
Author(s) -
Ahn WS.,
Bahk JH.,
Lim YJ.,
Kim YC.
Publication year - 2002
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1046/j.1365-2044.2002.02657.x
Subject(s) - bevel , tuohy needle , deflection (physics) , medicine , perpendicular , anatomy , surgery , geometry , structural engineering , mathematics , physics , optics , catheter , engineering , seldinger technique
Summary This study was performed to determine how the use of an introducer affects the extent to which a needle deflects during a spinal or combined spinal‐epidural injection. A polystyrene block was used to simulate the paraspinal area of the back. A line was drawn perpendicular to the edge of the block to use as a guide and to measure the deflection. The use of an introducer needle decreased the deflection in all the bevelled needles (p < 0.001). Depending on the direction of both the bevels, the deflection decreased as the introducer bevel was changed from the same direction, to right‐angles to bevel direction and then to a direction opposite to that of the spinal needle (p < 0.05). Deflection was decreased when a thick introducer was used (p < 0.001). The use of an introducer increased the deflection of the pencil‐point needle only in the deflection direction of the introducer (p < 0.001). The 18‐gauge Tuohy needle with a ‘backhole’ deflected more than the corresponding needle without a backhole (p < 0.001), and the spinal needle inserted through the Tuohy needle with a backhole deflected more (p = 0.002). Besides the tip type and gauge, the deflection of a spinal needle depends upon the use of introducer, its gauge and bevel direction. The deflection of a Tuohy needle depends upon its design, gauge and the presence of a backhole.