Page 5 - CASA Bulletin of Anesthesiology 2019 Vol 6 No 5

Vol.6, No.5, 2019

Feature articles: Regional Anesthesia 主题：局部阻滞麻醉

A New Kid on the Block: Erector Spinae Plane Block

Lei Li, MD

Attending Anesthesiologist, Geisinger Medical Center, Danville, PA, USA

Highlights:
ESP block is an ultrasound guided paraspinal block that targets the musculofascial plane
between the erector spinae muscle and the transverse process of the vertebra . Wide application
to cover any trunk area
Pro: easy, effective, less concern of coagulation abnormality
Con: mechanism is unclear, effectiveness varies

Introduction:

Erector spinae plane (ESP) block is an ultrasound guided paraspinal block that targets the
musculofascial plane between the erector spinae muscle and the transverse process of the ver-
tebra. The nomenclature and technique were first described in 2016 for thoracic analgesia [1].
Since then ESP block has emerged as a simple, safe, and effective analgesic technique, support-
ed by abundant case reports and an increasing number of randomized controlled trials .

The exact mechanism of action remains unclear, but it is postulated that paravertebral local

anesthetic spread is a primary mechanism of action [2]. Studies of local anesthetic spread in
cadavers have some discrepancies. Forero et al [1] demonstrated that injectates diffuse anteri-
orly to the thoracic paravertebral space resulting in block of the ventral and dorsal rami of the
spinal nerve roots as well as the rami communicantes transmitting autonomic fibers to and from
the sympathetic ganglia . Radiological imaging further showed that a single injection at the lev-
el of the T5 transverse process produced craniocaudal spread between C7 and T8 . Magnetic
resonance imaging showed radiological spread to the intercostal spaces, neuroforaminal areas
and epidural spaces [3]. However, Ivanusic et al. [4] showed no spread to either paravertebral
space or ventral rami, and they alternatively proposed that ESP block involved lateral cutaneous

branches of intercostal nerves . Clinically, this blockade seems to provide much more extensive
analgesia than just involving superficial structures. The difference could have been attributed
to the notion that spread in cadavers may be more limited as they lack dynamic intra-thoracic
pressure changes from breathing movement . One proposed theory that may reconcile these con-
flicting results is that therapeutically effective spread may not always be detectable by current
means but is nevertheless sufficient to produce analgesia.
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