mTLIP vs QIPB for Postoperative Analgesia After Lumbar Instrumentation Surgery

Comparison of Ultrasound-Guided Modified Thoracolumbar Interfascial Plane Block Versus Quadro-Iliac Plane Block for Postoperative Analgesia After Lumbar Instrumentation Surgery

Lumbar instrumentation surgery is associated with severe postoperative pain due to extensive tissue dissection and prolonged muscle retraction during the procedure. Inadequate postoperative pain control may result in delayed mobilization, increased cardiopulmonary complications, and prolonged hospital stay. Ultrasound-guided regional analgesia techniques are increasingly used to improve postoperative pain management after lumbar spine surgery. The thoracolumbar interfascial plane (TLIP) block has been shown to provide effective analgesia for lumbar instrumentation surgery, and its modified technique (mTLIP) has been reported to enhance postoperative pain control. The quadro-iliac plane (QIP) block is a newly described fascial plane block with promising results in lumbar spine surgery. This randomized controlled trial aims to compare the postoperative analgesic effectiveness of the modified thoracolumbar interfascial plane block and the quadro-iliac plane block in patients undergoing lumbar instrumentation surgery.

Lumbar instrumentation surgery is commonly associated with moderate-to-severe postoperative pain due to extensive tissue dissection and prolonged muscle retraction. Inadequate pain control may lead to delayed mobilization, increased cardiopulmonary complications, and prolonged hospital stay.

Ultrasound-guided regional analgesia techniques, particularly fascial plane blocks, are increasingly used as part of multimodal analgesia in lumbar spine surgery. The thoracolumbar interfascial plane (TLIP) block is an established technique that provides effective analgesia and has been modified to improve its clinical application, resulting in the modified thoracolumbar interfascial plane (mTLIP) block. Previous studies have demonstrated the effectiveness of mTLIP for postoperative analgesia after lumbar instrumentation surgery.

The quadro-iliac plane block (QIPB) is a recently described ultrasound-guided fascial plane block. Early reports suggest that QIPB may provide effective analgesia in lumbar spine procedures; however, comparative evidence with established techniques remains limited.

This prospective randomized controlled trial aims to compare bilateral ultrasound-guided mTLIP and QIPB performed at the end of surgery in patients undergoing elective lumbar instrumentation surgery under general anesthesia, to evaluate whether QIPB can be considered a safe and effective alternative to mTLIP for postoperative analgesia.

Inclusion Criteria:

• Age between 18 and 65 years
• Classified as American Society of Anesthesiologists physical status I-III
• Scheduled for elective lumbar instrumentation surgery under general anesthesia
• Provision of written informed consent

Exclusion Criteria:

• Use of anticoagulant medications or presence of bleeding diathesis
• Known allergy or hypersensitivity to local anesthetics or opioid drugs
• Infection at the planned block site
• Alcohol or drug dependence
• Cognitive impairment preventing reliable pain assessment
• Pregnancy or lactation
• History of previous lumbar spine surgery
• Diabetes mellitus
• Renal or hepatic insufficiency