Continuous Erector Spinae Block for Analgesia Following Lumbar Decompression: A Randomized Controlled Study

Lumbar spinal surgery is common, and the incidence of spinal fusion has increased dramatically over the past three decades. Patients requiring spinal surgery are typically prescribed several analgesics, (including opioids) while awaiting surgery. Postoperatively, use of high doses of opioids or anti-inflammatory medications have drawbacks. Severe post-operative pain is reported by 45-80% of patients and rates are generally higher in the opioid tolerant patients.

Regional anesthesia (blocking nerves with local anesthetics) works locally, thereby avoiding many side effects associated with other analgesics. One type of nerve block is called erector spinae plane block (ESP). Single injection nerve blocks have been found to decrease pain, nausea, and opioid consumption, while increasing patient satisfaction and quality of recovery. However, these effects only last for 24 hours or less while the worst pain occurs around 36 hours after surgery. Surgeon-placed indwelling catheters could allow infusions of local anesthetics for 54 hours.

This randomized control trial seeks to assess the effectiveness of surgeon-placed ESP catheters for pain control after lumbar spine surgery.

Hypothesis: Patients receiving a cESP will have less pain, improved quality of recovery, and opioid use following lumbar fusion surgery than those receiving current standard of care pain management.

Methodology: Adult patients undergoing lumbar spine surgery under orthopedic surgery in Halifax will be eligible. The study will include 100 participants, randomly assigned to 2 study arms of 50 participants (1:1 basis to Ropivacaine and placebo groups). At the end of surgery, the surgeon will place the ESP catheters in all study patients under sterile conditions before closing the wound. Ropivacaine 0.5% or normal saline (placebo) 15ml will be injected through each catheter (total 30ml). In the postanesthetic care unit (PACU), two elastomeric pumps will be attached to the ESP catheters. These will be filled with either Ropivacaine 0.2% or normal saline (placebo). The elastomeric pumps are small bottle that patients can carry with them after discharge home. The pumps automatically run at an infusion rate of 10 ml/hr for 54 hours. All patients will also receive the standard of care for pain management for this patient population, which is opioid based with acetaminophen. A quality of recovery (QoR-15) questionnaire will be completed at 72 hours post-operatively. Pain, catheter complication, and opioid use data will be gathered from the patient's charts at 24, 48, and 72 hours post-operatively. At 3- and 6-month follow-ups, patients will complete the Brief Pain Inventory questionnaire. We will analyze differences in pain and opioid consumption at 24, 48, and 72 hours, quality of recovery index scores at 72 hours, postoperative complication rates, and persistent pain at 3 and 6 months.