Search

Since its description in 2016, the erector spinae plane block (ESPB) has become a widely employed regional anesthetic technique and kindled interest in a range of related techniques, collectively termed intertransverse process blocks. There has been ongoing controversy over mechanism of action of the ESPB, mainly due to incongruities between results of cutaneous sensory testing, clinical efficacy studies, and investigations into the neural structures that are reached by injected local anesthetic (LA). This paper reviews the spread of LA to the paravertebral and epidural space and the cutaneous anesthesia in ESPB, with specific emphasis on the dorsal root ganglion (DRG). We hypothesize that the DRG, due to its unique and complex microarchitecture, represents a key therapeutic target for modulation of nociceptive signaling in regional anesthesia. This paper discusses how the anatomical and physiological characteristics of the DRG may be one of the factors underpinning the clinical analgesia observed in ESPB and other intertransverse process blocks. [ABSTRACT FROM AUTHOR]

Background: Both the transversus abdominis plane (TAP) block and the anterior quadratus lumborum block (QLB) have been shown effective in reducing postoperative pain after laparoscopic inguinal hernia repair. Our hypothesis was that there is no difference in analgesic effect between the two blocks for this procedure. Methods: In this prospective, double‐blind, randomised controlled study, 60 adult patients undergoing laparoscopic inguinal hernia repair were equally randomly assigned to either a preoperative TAP block or an anterior QLB. The primary outcome was oral morphine equivalent (OME) consumption at 4 h postoperatively. Secondary outcomes were OME consumption at 24, 48 h and 7 days, pain scores at rest and when coughing, nausea, and level of sedation measured at 1, 2, 3, 24, and 48 h and 7 days postoperatively. Results: Fifty‐three patients completed the study. There was no significant difference in OME consumption at 4 h postoperatively, TAP group (10.3 ± 7.85 mg) (mean ± SD) versus the anterior QLB group (10.9 ± 10.85 mg) (p =.713). The pain scores were similar at rest and when coughing during the 7 day observation period, as were the level of sedation and incidence of nausea. There were no cases of serious side‐effects or muscle weakness of the thigh on the same side as the block. Conclusion: There is no difference in OME consumption, pain, nausea or sedation between the TAP and the anterior QLB. Thus, the choice between the two blocks in a clinical setting of laparoscopic inguinal hernia repair should be based on other aspects, such as skills, practicalities, and potential risks. [ABSTRACT FROM AUTHOR]

Background 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 use MRI to investigate the spread of the local anesthetic (LA) and the corresponding cutaneous loss of sensation to pinprick and cold. Methods Ten volunteers received a right-sided ESPB at the level of the seventh thoracic vertebra (Th7), consisting of 30 mL 2.5 mg/mL ropivacaine with 0.3 mL gadolinium. The primary outcome was the evaluation of the spread of LA on MRI 1-hour postblock. The secondary outcome was the loss of sensation to cold and pinprick 30–50 min after the block was performed. Results 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 and foraminal spread. Four volunteers had a loss of sensation both posterior and anterior to the midaxillary line, while six volunteers had a loss of sensation only on the posterior side. Conclusion 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 four volunteers. Sensory testing 30–50 min after an ESPB shows highly variable results, and generally under-represents what could be expected from the visualized spread on MRI 60 min after block performance. [ABSTRACT FROM AUTHOR]