Evaluating two approaches to the erector spinae plane block: an anatomical study

Abstract

Background and objectivesStudies show variable spread with thoracic erector spinae plane (ESP) injections. Injection sites vary from lateral end of the transverse process (TP) to 3 cm from the spinous process, with many not describing the precise site of injection. This human cadaveric study examined dye spread of ultrasound-guided thoracic ESP block at two needle locations.MethodsUltrasound-guided ESP blocks were performed on unembalmed cadavers. Methylene blue (20 mL, 0.1%) was injected in the ESP at the medial TP at level T5 (medial transverse process injection (MED), n=7) and the lateral end of the TP between T4 and T5 (injection between transverse processes (BTWN), n=7). The back muscles were dissected, and the cephalocaudal and medial-lateral dye spread documented.ResultsDye spread cephalocaudally from C4-T12 in the MED group and C5-T11 in the BTWN group, and laterally to the iliocostalis muscle in five MED injections and all BTWN injections. One MED injection reached serratus anterior. Dorsal rami were dyed in five MED and all BTWN injections. Dye spread to the dorsal root ganglion and dorsal root in most injections, though more extensively in the BTWN group. The ventral root was dyed in 4 MED and 6 BTWN injections. Epidural spread in BTWN injections ranged from 3 to 12 levels (median: 5 levels), with contralateral spread in two cases and intrathecal spread in five injections. Epidural spread in MED injections was less extensive (median (range): 1 (0–3) levels); two MED injections did not enter the epidural space.ConclusionAn ESP injection administered between TPs exhibits more extensive spread than a medial TP injection in a human cadaveric model.

Blockade of intercostobrachial nerve by an erector spinae plane block at T2 level: a case report

“…Contrastingly, most studies investigating ESP injection spread have reported that lateral spread is limited by the lateral boundary of the erector spinae muscles, thereby contradicting Ivanusic's finding [10]. Recently, Harbell et al [16] used cadavers and reported that ESP injection, administered between the transverse processes, and not on the posterior surface of the transverse process, would be the key to attaining involvement of the ventral rami in the paravertebral space. Considering this, we administered a local anesthetic into the ESP between the T2 and T3 transverse processes, resulting in successful blockade of the intercostobrachial nerve, which implied the anterior spread of the local anesthetic by the ESP block.…”

“…Nevertheless, the likelihood of anterior spread (i.e., the ventral rami involvement) seen with the ESP block has been challenged [10,13,14]. Cadaver evaluations and MRI studies in healthy volunteers have shown that ESP injection spreads dye and local anesthetic over multiple paravertebral and epidural segments [10,[15][16][17][18]. In addition, some clinical studies have utilized ESP blocks for analgesia after breast and abdominal surgery and have reported promising results [11,12].…”

Meta-Analysis of Open-Heart Surgery Pain Relief Using Transversus Thoracic Plane Blocks

“…(2) whether the allocation was hidden; (3) blinding of investigators and subjects; (4) blinding of study results; (5) completeness of the outcome data; (6) selective reporting of study results; and (7) other biases. Each included literature was evaluated in accordance with the abovementioned criteria and judged as "high risk of bias," "low risk of bias," or "unclear risk of bias."…”

“…Midsternotomy incision is considered the primary source of pain, with the most severe pain occurring within the frst 24 h. Te sternal region is mainly sensed by the intercostal nerves [5]. Sensation in this region was mainly innervated by the anterior cutaneous branch of the intercostal nerve, which migrated from the intercostal nerve in the paraspinal region [6]. Transverse thoracic muscle plane (TTMP) block is a blocking technique developed in recent years.…”