BLOCK AT A GLANCE
Interfascial plane injection of local anesthetic (LA) between the erector spinae muscles and the transverse processes at the segmental levels supplying the area of interest.
Indications: Analgesia for rib fractures, back surgery, and chest wall procedures. Other potential indications are currently under investigation
Goal: Spread of an LA in the plane deep to the erector spinae muscles aiming for a craniocaudal distribution along several vertebral levels to block the posterior (and possibly anterior) rami of the spinal nerves
Local anesthetic volume: 20 to 30 mL
The erector spinae plane block (ESPB) is a novel interfascial plane technique, aiming to block the dorsal and ventral rami of the spinal nerves to provide multidermatomal analgesia of the cervical, thoracic, and lumbar levels. Several case reports and few randomized controlled clinical trials have been published supporting the clinical efficacy of the ESPB in a growing number of indications. The mechanisms of action are inadequately understood; spread into the paravertebral space is thought to be one of the possible sites of action but studies describing LA distribution after injection show considerable variability and conflicting results. Published reports describe single-shot techniques, followed by intermittent bolus and continuous infusion, performed primarily at the thoracic, lumbar, and some at the cervical level.
Specific Risks and Limitations
While there is insufficient data to remark on the risk of complications with an ESPB, a case of pneumothorax, a case of partial autonomic neuropathy, and a few cases of hematoma, suggest that the technique is not devoid of risks. Because injection targets can be well-identified with ultrasound (US) and the site of injection is distant from the neuraxis and major vascular structures, the potential for complications could be lower compared to a paravertebral block.
Because ESPB is a volume-dependent interfascial block, systemic levels of LAs could be higher than with most peripheral nerve blocks due to their absorption across a large surface. When performing an ESPB, consider using a pharmacologic marker (e.g., epinephrine), and be conservative with the LA dose especially in high-risk populations (e.g., elderly patients).
The erector spinae muscles comprise the iliocostalis, longissimus, and spinalis. They are located parallel along both sides of the spine; from the skull to the pelvis and sacral region, and from the spinous to the transverse processes extending to the ribs. They vary in size and structure at different levels of the spine. The erector spinae muscles are innervated by the dorsal rami of the spinal nerves and their function is to stabilize, extend, and laterally bend the spine (Figure 37-1).
Anatomy of the erector spinae muscles.
CROSS-SECTIONAL ANATOMY AND ULTRASOUND VIEW
The symmetrical erector spinae muscles lie over the ...