Efficacy of Combined Ultrasound-Guided Bilateral Lumbar Longissimus Plane Block and Multifidus Longissimus Plane Block Versus Conventional Wound Infiltration for Postoperative Analgesia in Elective Lumbar Spine Surgery: A Prospective, Patient and Assessor Blinded, Randomized Clinical Trial

Lumbar spine surgery is one of the most commonly performed procedures for degenerative spinal disorders, including lumbar disc herniation, spinal stenosis, and degenerative disc disease. Despite continuous advances in surgical techniques, anesthesia, and perioperative care, postoperative pain remains a major clinical challenge. Severe pain during the early postoperative period may impair respiratory function, delay ambulation, prolong hospitalization, reduce patient satisfaction, and increase the risk of chronic postsurgical pain and persistent opioid use. Consequently, optimizing postoperative analgesia has become a fundamental objective of contemporary perioperative care and Enhanced Recovery After Surgery (ERAS) protocols for spine surgery.

Current evidence strongly supports multimodal analgesia as the preferred strategy for postoperative pain management. This approach combines different analgesic modalities to improve pain control while minimizing opioid consumption and opioid-related adverse effects such as postoperative nausea and vomiting (PONV), sedation, respiratory depression, ileus, urinary retention, and delayed recovery. Among the available regional anesthesia techniques, ultrasound-guided paraspinal fascial plane blocks have recently gained considerable attention because they provide targeted blockade of the dorsal rami of the lumbar spinal nerves with minimal invasiveness and an excellent safety profile.

Local anesthetic wound infiltration remains one of the most widely used analgesic techniques after lumbar spine surgery because it is technically simple, inexpensive, and familiar to surgeons. However, its analgesic efficacy may be limited by restricted distribution of the local anesthetic and inadequate coverage of deeper pain-generating structures. Consequently, increasing interest has focused on ultrasound-guided interfascial plane blocks capable of producing broader and more consistent analgesia. Previous investigations have mainly evaluated thoracolumbar interfascial plane (TLIP) block, modified TLIP block, and erector spinae plane block (ESPB), all of which have demonstrated encouraging reductions in postoperative pain scores and opioid requirements. Nevertheless, evidence regarding the combined use of Lumbar Longissimus Plane (LLP) block and Multifidus Longissimus Plane (MLP) block remains scarce.

The LLP block targets the interfascial plane between the iliocostalis and longissimus muscles, whereas the MLP block targets the plane between the longissimus and multifidus muscles. From an anatomical perspective, combining both techniques may allow wider spread of local anesthetic around the medial and intermediate branches of the dorsal rami, potentially producing more comprehensive posterior lumbar analgesia than either single-plane block or conventional wound infiltration. However, this hypothesis has not previously been adequately evaluated in randomized clinical trials.

The present study was therefore designed as a prospective, patient- and assessor-blinded, parallel-group randomized controlled trial to compare ultrasound-guided bilateral combined LLP and MLP blocks with conventional wound infiltration in adult patients undergoing elective lumbar spine surgery under general anesthesia. Fifty ASA physical status I-II patients were randomly allocated to receive either bilateral ultrasound-guided combined LLP and MLP blocks after wound closure or standard wound infiltration with bupivacaine before wound closure.

The primary outcome was postoperative pain intensity measured using the Visual Analogue Scale (VAS) during the first 48 postoperative hours. Secondary outcomes included postoperative opioid requirements, time to first rescue analgesic request, postoperative nausea and vomiting, antiemetic consumption, patient satisfaction, time to first mobilization, hospital length of stay, and the incidence of block-related adverse events and local anesthetic systemic toxicity.

The study was conducted at the Department of Anaesthesia, Surgical Intensive Care, and Pain Management, Aswan University Hospital, Faculty of Medicine, Aswan University, Egypt. Ethical approval was obtained before patient enrollment, and the trial was conducted in accordance with the Declaration of Helsinki, Good Clinical Practice guidelines, and the CONSORT 2010 statement. By investigating a novel combination of two ultrasound-guided paraspinal fascial plane blocks, this trial aims to expand the evidence base for opioid-sparing regional anesthesia techniques and provide clinically relevant data that may support future multimodal analgesic protocols and larger multicenter randomized studies in lumbar spine surgery.