Background: Percutaneous endoscopic lumbar discectomy (PELD), a minimally invasive spinal technique for lumbar disc herniation (LDH), has gained popularity globally and yielded satisfying results. However, PELD is often performed on awaking patients to avoid nerve injury, thus the intraoperative analgesia of PELD is sometimes insufficient. The effect of intrathecal morphine (ITM) has been well proved in various surgical specialties, and this study aims to investigate the effectiveness and safety of ITM on PELD. Methods: The intrathecal morphine for percutaneous endoscopic lumbar discectomy (IMPELD) trial is a double-blind, randomized, placebo-controlled trial. The 90 eligible LDH patients undergoing PELD will be randomly assigned to receive either ITM or placebo during spinal anesthesia, at a 1:1 ratio, with a one-month follow-up period. Average intraoperative pain intensity will be the primary outcome. Secondary outcome measures include intraoperative pain intensity at each 30 min intraoperatively, postoperative pain intensity, perioperative analgesia requirements, functional evaluation, radiographic characteristics, overall satisfaction, in-hospital characteristics and adverse events. Discussion: Currently, there is a lack of scientific evidence to provide a reliable method to reduce intraoperative pain of PELD. The IMPELD trial was designed to provide evidence regarding whether 100 ug of ITM is an effective and safe coanalgesic approach for PELD procedure.

The authors have declared no competing interest.

ChiCTR2000039842

This study was funded by Interdisciplinary Clinical Research Project of Peking University First Hospital (2021CR31).

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study was approved by the Institution Review Board of Peking University First Hospital (2020-289).

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All data produced in the present study will be available at the end of the trial and will be available upon reasonable request to the authors.