J Korean Pain Soc.  1996 Nov;9(2):349-353.

Predicting Factors for the Distance from Skin to the Epidural Space with the Paramedian Epidural Approach

• Shim JC
• Lee ME
• Kim DW

Abstract

BACKGROUND: Although the paramedian approach for epidural blockade is useful in some clinical situation, the parameters which are correlated with the distance from skin to the epidural space has not been established.
METHODS
We studied in 145 patients having elective continuous epidural blocks for relief of postoperative pain. All blocks were performed using paramedian approach with Tuohy needle in the lumbar (group l, n=100) and thoracic (group 2, n=45) area. We measured the distance from skin to the epidural space, body weight, height, and the angle between the shaft of the needle and the skin. Data were analyzed by linear regression. The relationships between parameters identified by the F-test with a P value of less than 0.05 were considered statistically significant.
RESULTS
The mean distance from skin to the lumbar epidural space was 4.4+/-0.7cm. Significant correlation between the body weight and the depth of lumbar epidural space (gamma value: 0.492) was noted with regression equation of depth (cm)=2.293+0.034 x body weight (kg). Also the significant correlation between the ponderal index (PI) and the depth of lumbar epidural space (gamma value: 0.539) was noted with regression equation of depth (cm)=1.703+0.07 x PI, The mean distance from skin to the thoracic epidural space was 5.2+/-0.7cm which did not correlated with other anatomic measurements.
CONCLUSIONS
We found that PI and body weight are the suitable predictors of the depth of the lumbar epidural space, but not the thoracic epidural space.

Keyword

Predictors; Techniques: epidural; paramedian approach; Anatomic depth

MeSH Terms

Body Weight
Epidural Space*
Humans
Linear Models
Needles
Pain, Postoperative
Skin*