The Feasibility of Performing Erector Spinae (ESP) Nerve Block in Bariatric Patients; a Case Series Stud

This study is a pilot study to assess the effectiveness of erector spinae (ESP) nerve blocks for postoperative pain control following bariatric surgery. Currently, there are mainly case series/pilot studies describing the use of ESP nerve blocks for postoperative pain control in abdominal procedures; of these only one uses this treatment modality for bariatric procedures. The population undergoing bariatric surgery poses specific challenges to postoperative pain management. They often have comorbid obstructive sleep apnea, which puts them at greater risk for ventilatory depression when treated with parenteral opioids. This risk can be reduced with regional techniques. The ESP nerve blocks provide visceral and somatic pain coverage as opposed to the more commonplace transversus abdominis plane nerve block which only provides somatic coverage. This means that the ESP nerve blocks will cover incisional pain as well as the discomfort associated with the pain from the procedure itself. This study intends to build on current knowledge by proving that the use of ESP in the post-operative are providing a significant reduction in pain scores as well as reducing the need for parenteral opioids. Thus, decreasing the risk of postoperative ventilatory complications.

In preparation for this study, three pilot studies were reviewed. The studies assessed the usefulness of ESP nerve blocks on patients undergoing abdominal surgery. Single-shot bilateral ESP blocks were performed in the first two studies. One of the studies, patients undergoing ventral hernia repair and the other for patients undergoing bariatric surgery. The third pilot study used bilateral ESP blocks followed by a continuous infusion on one patient undergoing an open prostatectomy with bladder reconstruction. All the ESP blocks were placed preoperatively at the T7 transverse process. In the studies using a single shot technique 20-30 ml of ropivacaine 0.5% was used. For the continuous ESP catheter an initial bolus of bupivacaine 0.25% 10 mls followed by continuous infusion rate of 6 ml/hr bilaterally. All showed a significant reduction numerical rating scale (NRS) as a primary outcome. The secondary outcome of reduced 24-hour parenteral opioid consumption was also achieved by all three studies.