Deflection of spinal needles by the bevel

Area of Science:

• Neurosurgery
• Medical Device Engineering
• Anatomical Studies

Background:

• Spinal needle trajectory is critical for accurate neuraxial anesthesia and interventions.
• Understanding needle-tissue interaction is essential for procedural safety and efficacy.

Purpose of the Study:

• To investigate the impact of bevel orientation on spinal needle path deviation.
• To evaluate methods for minimizing needle deviation in challenging tissue.

Main Methods:

• Bevelled spinal needles (22 and 25 gauge) were passed through tough meat models.
• Needle path deviation was measured in relation to bevel orientation.
• The effect of an introducer on needle deviation was assessed.

Main Results:

• Needles deviated approximately 1 mm per cm of travel away from the bevel surface.
• Using an introducer reduced deviation by limiting unsupported needle travel.
• Pencil-point needles exhibited less deviation compared to bevelled needles.

Conclusions:

• Bevel orientation is a key factor influencing spinal needle trajectory.
• Introducers and pencil-point designs can enhance needle accuracy and potentially reduce complications.