### INTRODUCTION

### MATERIALS AND METHODS

### RESULTS

##### Table 1

Variable | Value (n = 100) |
---|---|

Age (yr) | 63.8 ± 7.5 |

Sex (M/F) | 54/46 |

Height (cm) | 160.9 ± 8.4 |

Weight (kg) | 59.0 ± 9.6 |

##### Table 2

^{} Values are presented as mean ± SD. Ad: needle insertion distance along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Alpha: needle insertion angle along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Cd: needle insertion distance along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Theta: needle insertion angle along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Xd: distance from Point X to the spinous process, Dd: needle insertion distance along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Delta: needle insertion angle along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Yd: distance from Point Y to the spinous process.

##### Table 3

^{} Ad: needle insertion distance along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Alpha: needle insertion angle along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Cd: needle insertion distance along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Theta: needle insertion angle along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Xd: distance from Point X to the spinous process, Dd: needle insertion distance along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Delta: needle insertion angle along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Yd: distance from Point Y to the spinous process. β: standardized regression coefficient, t: t-value. *P value < 0.05, †P value < 0.01, ‡P value < 0.001.

##### Table 4

^{} Ad: needle insertion distance along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Alpha: needle insertion angle along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Cd: needle insertion distance along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Theta: needle insertion angle along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Xd: distance from Point X to the spinous process, Dd: needle insertion distance along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Delta: needle insertion angle along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Yd: distance from Point Y to the spinous process. β: standardized regression coefficient, t: t-value. *P value < 0.05, †P value < 0.01, ‡P value < 0.001.

##### Table 5

^{} Ad: needle insertion distance along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Alpha: needle insertion angle along the line drawn from the point 40 mm external from the spinous process, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Cd: needle insertion distance along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Theta: needle insertion angle along the line drawn from Point X, grazing the exterior margin of the lamina and arriving at the 1/2 depth of the intervertebral foramen, Xd: distance from Point X to the spinous process, Dd: needle insertion distance along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Delta: needle insertion angle along the line drawn from Point Y to the 1/2 depth of the intervertebral foramen without passing through the lung, Yd: distance from Point Y to the spinous process. β: standardized regression coefficient, t: t-value. *P value < 0.05, †P value < 0.01, ‡P value < 0.001.