Anatomical basis of erector spinae plane block: a dissection and histotopographic pilot study

Abstract

Purpose Erector spinae plane (ESP) block is an interfascial blockade used in different clinical scenarios. This study investigated the ventral extent of dye diffusion in ESP block. Methods The ultrasound-guided ESP block was bilaterally performed with an injection at the T5 vertebral level (21-Gauge, 50 mm needle), using diluted black tissue marking dye (20 mL; 1:4 ratio with standard saline solution) instead of local anesthetic on two fresh-frozen corpses within the body donation program of the University of Padova. Subsequently, the gross anatomical dissection was performed by a combined posterior plus anterior approach, and the histotopographic examination completed. Results Macroscopically by gross anatomical dissection, the dye spreading ranged on the dorsal side of the chest from T2/3 to T10/11 with an extension up to 10 cm laterally, and on the ventral side of the chest from T2/3–T9/10. Microscopically by histotopographic examination, the dye diffused ventrally to the intercostal spaces (2–3 and 5–6 spaces on the right and left, respectively) by following the blood vessels coupled to the dorsal nerve passing through the costotransverse foramen. Conclusions The anterior pathway of dye diffusion from the site of injection within the erector spinae muscle group during an ESP block seems to follow the blood vessels and dorsal rami of spinal nerves, suggesting the passing through the costotransverse foramen to reach the anterior paravertebral space and the intercostal nerves. These findings display an anterior histotopographic diffusion of dye resembling a paravertebral block.

Analgesic efficacy of erector spinae plane blocks for lumbar spine surgery: a randomized double-blind controlled clinical trial

“…Later, in a single blind, randomized controlled study with NSAIDs without ketamine, Zhang et al , only found a decrease in morphine consumption and NRS scores at rest in the first 12 hours, with no difference at 24 hours (puncture in L3) 12. All in all, the data in the current literature are similar to our results and tend to demonstrate only slight benefits in terms of morphine sparing or pain scores in favor of ESPB at lumbar level 10–18. In our study, we evaluated the long-term benefits in favor of ESPB (at 3 months), because no data were available for this major end point for patients (chronic pain, opioid abuse).…”

“…To enhance the multimodal approach and opioid sparing, several local anesthesia (LA) administration routes have been evaluated: intravenous, infiltration (wound), regional (paravertebral, epidural and spinal) 6–9. Recently, lumbar erector spinae plane blocks (ESPB) have been proposed as an alternative to other regional techniques 9–14. Previous cadaveric, CT scan imaging and randomized studies have inconsistently reported clinical efficacy (Numerical Rating Scale (NRS) pain score, opioid sparing) or effective dye diffusion due to the unpredictable injectate spread 10–14.…”

“…Previous cadaveric, CT scan imaging and randomized studies have inconsistently reported clinical efficacy (Numerical Rating Scale (NRS) pain score, opioid sparing) or effective dye diffusion due to the unpredictable injectate spread 10–14. Furthermore, most studies published include various types of spinal surgery (laminectomy, decompression, fusion, discectomy), different levels of injection (thoracic, lumbar), absence of multimodal analgesia and ‘Enhance Recovery After Surgey’ (ERAS) protocols or short-term evaluation without any analysis of chronic pain 10–19. Moreover, there are no randomized trials on the same levels of surgery 10–19…”

“…Furthermore, most studies published include various types of spinal surgery (laminectomy, decompression, fusion, discectomy), different levels of injection (thoracic, lumbar), absence of multimodal analgesia and ‘Enhance Recovery After Surgey’ (ERAS) protocols or short-term evaluation without any analysis of chronic pain 10–19. Moreover, there are no randomized trials on the same levels of surgery 10–19…”

Is the nomenclature of posterior thoracic fascial plane blocks becoming unnecessarily overcomplicated?

“…There is clear evidence that injectate deposited deep to the erector spinae at the level of the transverse process frequently spreads far beyond the lateral margin of iliocostalis. [5][6][7] It seems unlikely that there could be any mechanistic difference between the proposed technique and ESPB.…”