Anesth Pain Med.  2017 Apr;12(2):132-136. 10.17085/apm.2017.12.2.132.

The Skin-to-epidural distance of parturients by ultrasonography: sitting position versus left lateral position

• Chun EH
• Chung RK
• Kim YJ
• Jin SH

• KMID: 2379732
• DOI: http://doi.org/10.17085/apm.2017.12.2.132

Abstract

BACKGROUND
Pre-procedural lumbar ultrasound scanning is a reliable tool to estimate the skin to epidural distance (SED). We conducted an observational study to compare the SED between the sitting position and lateral position using pre-procedural ultrasound imaging of the lumbar spine in parturients.
METHODS
Using a 2-5 MHz curvilinear transducer, we obtained images of the lumbar interspaces from L2-3 to L5-S1 in the paramedian sagittal oblique view. The individual distance from the skin to the ligamentum flavum-dura mater unit was measured at the level of L2-3, L3-4, L4-5, and L5-S1 in the left lateral position (distance in lateral position; D-lat). Subsequently, participants were placed in the sitting position, and the distance was measured in the same manner (distance in sitting position; D-sit). Data were grouped according to body mass index (BMI; kg/m²) measurements of ≥ 25 or < 25 and analyzed. The primary outcome was the change determined by ultrasound between D-lat and D-sit at the same lumbar level according to position.
RESULTS
Thirty parturients were studied. The difference between D-lat and D-sit in the same lumbar level was not statistically significant. The mean changes between D-lat and D-sit in the same lumbar level were less than 0.18 cm. In BMI ≥ 25 group, the difference between D-lat and D-sit were greater than that of BMI < 25 group at L3-4 level (P = 0.042).
CONCLUSIONS
It is important for clinicians to consider that position change is associated with greater differences in SED in obese parturients (BMI ≥ 25) compared with thin parturients (BMI < 25). For obese parturients, the sitting position may be helpful.

Keyword

Epidural; Obstetric; Ultrasound

MeSH Terms

Body Mass Index
Observational Study
Skin
Spine
Transducers
Ultrasonography*

Figure

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  Fig. 1 Ultrasound measurement the distance from the skin to the ligamentum flavum-dura mater Unit (LF-DM) in the paramedian sagittal oblique view. Anterior complex; anterior dura mater and posterior longitudinal ligament

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