PT  - JOURNAL ARTICLE
AU  - Sørenstua, Marie
AU  - Leonardsen, Ann-Chatrin Linqvist
AU  - Ræder, Johan
AU  - Vamnes, Jan Sverre
AU  - Zantalis, Nikolaos
TI  - EP157 Spread of local anesthetics after erector spinae plane block – a magnetic resonance imaging study in healthy volunteers
AID  - 10.1136/rapm-2023-ESRA.218
DP  - 2023 Sep 01
TA  - Regional Anesthesia & Pain Medicine
PG  - A124--A125
VI  - 48
IP  - Suppl 1
4099  - http://rapm.bmj.com/content/48/Suppl_1/A124.3.short
4100  - http://rapm.bmj.com/content/48/Suppl_1/A124.3.full
SO  - Reg Anesth Pain Med2023 Sep 01; 48
AB  - Background and Aims Erector Spinae Plane Block (ESPB) is a truncal fascial block with a disputed mechanism and anatomical site of effect. This study aimed to perform a one-sided ESPB and utilize magnetic resonance imaging (MRI) to investigate the spread of the local anesthetic (LA) and the corresponding dermatomal loss of sensation to pinprick and cold.Methods Ten volunteers received a right-sided ESPB at the level of Th7, consisting of 30 ml 2,5 mg/ml ropivacaine with 0,3 ml gadolinium. The loss of sensation to cold and pinprick was registered 30 minutes after the block was performed. One-hour post block an MRI was performed.Abstract EP157 Figure 1 The extent of spread was evaluated using MRI after injection of 30 ml 2,5 mg/ml ropivacaine with 0,3 ml gadolinium to a total volume of 30,3 ml at the level of Th7. The extent of spread to the paravertebral space, the intercostal space, foramina, epidural space, and Erector spinae muscles are represented with bars for each of the ten volunteers. Contralateral epidural and foraminal spread are marked with an asteriskAbstract EP157 Figure 2 Magnetic resonance imaging of a right-sided Erector spinae plane block performed at the level of Th7. A) Axial view at the Th6 level demonstrating contrast spread to the paravertebral space, neural foramina, and the epidural space (yellow arrow). B) Axial view at the Th6 level demonstrating the spread of contrast to the contralateral epidural space and neural foramina (yellow arrow). C) Sagittal view of the spinal canal demonstrating contrast to the epidural space (yellow arrows) from the level of Th6 to Th8Abstract EP157 Figure 3 Cutaneous mapping of loss of sensation to cold and pin-prick after an Erector spinae plane block was performed at the level of Th7 using an injectate containing 30 ml of ropivacaine and 0,3 ml gadolinium. Individual photos are marked with volunteer numberResults All volunteers had a spread of LA on MRI in the erector spinae muscles and to the intercostal space. 9/10 had spread to the paravertebral space and 8/10 had spread to the neural foramina. 4/10 volunteers had spread to the epidural space. One volunteer had extensive epidural spread as well as contralateral epidural spread. Four volunteers had a loss of sensation both posterior and anterior to the midaxillary line, while six volunteers had loss of sensation only on the posterior side.Conclusions We found that LA consistently spreads to the intercostal space, the paravertebral space and the neural foramina after an ESPB. Epidural spread was evident in 4 volunteers. Sensibility testing after an ESPB is variable and does not consistently reflect the visualized spread on MRI.Compiled MR picture.jpg