Prediction of midline depth from skin to cervical epidural space by lateral cervical spine X-ray

Abstract

Background:Previous studies have shown that measuring the distance from the skin to the ligamentum flavum by ultrasound preceding cervical epidural block can be beneficial in excluding false loss of resistance. However, the measurement value using ultrasound may vary depending on the degree of operator experience. Therefore, we aimed to determine the depth from skin to cervical epidural space by using lateral cervical spine X-ray, which is a more intuitive method. Methods: We enrolled 102 adult patients who were scheduled to undergo cervical epidural anesthesia for vascular bypass surgery of upper arm. After attaching a steel rod on the needle insertion site, lateral cervical spine X-ray was taken before the epidural procedure. We measured the distance from the steel rod to the midpoint of interlaminar space on the spinolaminar line. The X-ray depth was compared with needle depth. Results: Of the 102 enrolled patients, 18 patients including 13 in whom we were unable to measure X-ray depth were excluded from the analysis. In total, 84 patients were included in the analysis. Concordance correlation coefficient between the X-ray-measured depth and needle depth was 0.925. Bland-Altman analysis indicated

Prediction of the Cervical Epidural Space Depth from the Skin Using Cervical X-Ray, During Cervical Epidural Block with Paramedian Approach

“…Previous studies have shown higher CCC values using ultrasonography and x-ray lateral images due to their prospective study designs. 32 , 33 The study by Pak et al 13 showed similar results to our study.…”

“…Various methods have been used to predict the depth from the skin to the epidural space, including demographic data and imaging modalities such as MRI, CT, Ultrasound, and x-rays. 13,[30][31][32][33][34][35] However, most studies focus on the median approach rather than the paramedian approach. Ultrasound has limitations due to LF discontinuity and difficulties in obese patients.…”