Comparison of Median, Intermediate, and Lateral Approach in the Ultrasound-Guided Sacral Erector Spinae Plane Block: A Cadaveric and Radiologic Study

Abstract

Backgrounds: Erector spinae plane block (ESPB) has become very popular for post-operative and chronic pain management. It is aimed to observe the contrast agent distributions of three different methods anatomically and radiologically in ultrasound-guided sacral ESPB interventions.Materials and Methods: Six cadavers were enrolled and they were grouped into three groups; median, intermediate, and lateral approaches. An ultrasound-guided ESPB was performed with a mixture of radio-opaque and dye. After 30 minutes, the distribution of the solution was observed in the cadavers by computed tomography (CT) examination. Totally after 60 minutes of intervention, the median and intermediate groups of cadavers were dissected in order to observe the dye spread in the median group and the intermediate group. The lateral group dissection wasn’t performed according to radiologic findings.Results: CT images presented a pooling of the radio-opaque at subcutaneous tissue in the median group, at erector spinae in the intermediate group, and at gluteus maximus in the lateral group of cadavers. In addition to compartment spreads, images presented anterior transition of the contrast agent at only median group cadavers. Dissection findings presented pooling of the methylene blue at subcutaneous tissue between S1 and S5 horizontal planes at the median group. The red acrylic paint spread was detected between L2-S3 levels in the erector spinae muscle group.Conclusion: Radiocontrast dye was detected at superficial, erector spinae, and gluteus maximus compartments respectively at median, intermediate, and lateral cadaver groups both radiological and anatomically. Anterior transition of the radiocontrast was detected in only the median cadaver group.