Depth of the thoracic epidural space in paramedian approach.
OBJECTIVE
To define the depth of the thoracic epidural space in the paramedian axis.


METHODS
Retrospective study.


METHODS
Operating room of a tertiary care medical center.


METHODS
Nine hundred ninety-eight consecutive adults scheduled for elective major cardiothoracic/abdominal surgery and postoperative thoracic epidural pain control.


METHODS
The thoracic epidural pain control was accomplished via paramedian approach at indicated levels in 977 of 998 patients with uniform and well-standardized technique routinely performed in this institute.


METHODS
The depth of the epidural space, defined as the distance from the needle tip just penetrating the epidural layer to the overlying skin, was measured by directly checking the length markers displayed on the needle. Association between demographic variables and epidural depths at different thoracic levels was analyzed.


RESULTS
The mean thoracic epidural depth was (mean+/-SD) 5.11+/-0.94 cm, which was positively correlated with the body weight (regression coefficient=0.039, P<.001) and body mass index but was unrelated to sex, age, or body height. On stepwise linear multivariate regression analysis, each 10 kg of increase in body weight would result in a 0.39-cm increase in the depth. Besides, this paramedian depth was 0.34 cm longer at upper thoracic levels (T9 and upper) than that at lower levels (T10 and lower, P<.001).


CONCLUSIONS
Body weight, body mass index, and anatomical levels determine the paramedian thoracic epidural depth. The greater the patient's weight and the higher the puncture level, the deeper the thoracic epidural space from the body surface.
Lai
Hui-Chin
HC
Department of Anesthesiology, Taichung Veterans General Hospital, Taichung 40766, and Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
Liu
Tsun-Jui
TJ
Peng
Shih-Kuei
SK
Lee
Kwong-Chiu
KC
Luk
Hsiang-Ning
HN
Lee
Shu-Chuan
SC
D000328:Adult; D000368:Aged; D015360:Analgesia, Epidural / Q000379:methods*; D004824:Epidural Space / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010149:Postoperative Pain / Q000628:therapy*; D012189:Retrospective Studies; D013904:Thoracic Vertebrae