Optimal Point and Angle of Needle insertion in Midline Spinal Puncture in Korean Young Adult Male

Jung, Chul Woo; Ahn, Won Sik

Abstract

BACKGORUND: in spinal anesthesia, we usually walk over the interspinous space with a repetitive insertion-withdrawal-redirection-advance chain, which is annoying and time consuming, let alone the discomfort of patients. The aim of this study was to offer a guideline for the optimal point and angle of needle insertion performing spinal anesthesia and to strengthen the basis of the practice of spinal anesthesia.
METHODS
Twenty men were evaluated for this study. While in a head-to-knee position, a simple X-ray was taken and L2-3, L3-4, and L4-5 interspaces were measured. Two tangential lines were drawn between the upper and lower spinous process and the points where these two lines meet the skin were marked. The perpendicular line from the most prominent point of the spinous process to the skin was checked(S). The distances from S to the cephalic point of the tangential line (D1) and to the caudal point of the tangential line (D2) were measured. Perpendicular lines were drawn on the point where tangential lines meet skin and the angles between perpendicular lines and tangential lines were measured (A1, A2).
RESULTS
Mean distance (MD, [D2-D1] / 2) and mean angle (MA, [A1+A2] / 2) were calculated as 3.59+/-0.64cm, 11.9+/-4.75 for L2-3, 3.72+/-0.50 cm, 11.18+/-1.65degree for L3-4, and 3.71+/-0.61cm, 11.03+/-4.95degree for L4-5 (mean+/-SD).
CONCLUSiONS
At any lumbar level, we could approach the interspinous space from the insertion point of 3.6-3.7cm caudal from the spinous process and with the angle of the cephalic direction of about 11-12degree optimally. it can be the guideline for the insertion of the needle in spinal anesthesia and we can get some safe margins for insertion from the measured data.