Is the Erector Spinae Plane block useful for anti-nociception and analgesia in lumbar spine surgery? A narrative review of the literature and opinion paper

We aimed at determining whether the Erector Spinae Plane (ESP) block is useful for providing anti-nociception and analgesia to patients beneficiating from lumbar spine surgery. Using the keywords "Erector Spinae Plane block" and "lumbar" or "spinal surgery" in Pubmed, the Cochrane Library Database, and Google Scholar (end of search in March 2021), we identified 19 relevant papers involving 534 patients. Injection levels, and type, dilution, or volume of local anesthetic agent solution differed between studies. The main studied outcomes were postoperative pain control, and opioid consumption. Only one study compared the ESP block with another loco -regional technique. All published papers conclude that ESP block reduces postoperative pain scores and rescue medication use. As a corollary, ESP block appears promising in this indication for several reasons. First, it is easy to perform and does not have the same adverse effects or complications as neuraxial techniques. Second, even if the best site of injection as not been determined yet, skin puncture can be performed at distance from the surgical site, hence reducing the risk of surgical site infection by the loco-regional technique, and allowing its use as a rescue analgesic technique after surgery. Last, the incidence of ESP block complications seems low even if the number of studied patients is not wide enough to ascertain this fact for sure. Several unresolved questions are still pending. None of the published studies were randomized controlled trials with a group receiving a sham block, length of follow-up was limited to 48 hours, chronic pain was an exclusion criteria, and the pain scores were evaluated at rest. We conclude that the ESP block appears to be a safe and promising technique to be used as part of a multimodal analgesia protocol in lumbar spine surgery. Several studies are needed to precise its superiority and safety as compared to other techniques, its intraoperative opioid sparing effect, and its influence on longer term outcomes such as the development of chronic pain.