Erector spinae plane block: a systematic qualitative review

INTRODUCTION: The erector spinae plane (ESP) block is an interfascial block proposed to provide analgesia for chronic thoracic pain. It consists in an injection of local anesthetic in a plane between the transverse process and the erector spinae muscles group. EVIDENCE ACQUISITION: We performed a systematic review of literature following the PRISMA Statement Guidelines. The bibliographic search was conducted on September 2018. We included articles indexed in MEDLINE, EMBASE, Cochrane Library and Google Scholar. Search terms included the following: "erector spinae plane block" OR "ESP block" OR "erector spinae block." We identified 367 studies and after removal of 206 duplicates and exclusion of 18 records we manually searched 140 studies. EVIDENCE SYNTHESIS: We identified four randomized controlled trials, but the endpoints were heterogeneous preventing a statistical analysis; we performed then a qualitative review of the literature. Studies showed lower use of opioids and a longer time to first analgesic requirement in the ESP group. In one study, ESP block was found to be as effective as epidural analgesia. ESP block has a wide range of clinical indications. Its mechanism of action is still not thoroughly understood. Only two reports presented complications caused by the block. CONCLUSIONS: Although data suggests that ESP block is an easy and safe technique, more studies are needed to assess safety, complications rates and efficacy of this technique. In particular, we need well designed RCTs comparing ESP block to gold standard regional anesthesia technique. Nevertheless, ESP block is already a viable option for anesthesiologists all over the world.