Postoperative Pain Monitoring With ANI in Lumbar Spine Surgery

Comparison Of Postoperative Analgesic Efficacy Using Analgesia Nociception Index Monitoring In Patients Undergoing Elective Lumbar Spine Surgery: A Randomized Parallel-Group Study

This study aims to compare two different pain management methods in patients undergoing elective lumbar spine surgery. Patients are randomly assigned to receive either an ultrasound-guided erector spinae plane block (ESPB) or intravenous multimodal analgesia.

Postoperative pain will be assessed using both clinical pain scores and the Analgesia Nociception Index (ANI), a non-invasive monitoring system that evaluates pain-related responses based on heart rate variability. The goal of this study is to determine which method provides better postoperative pain control.

Effective postoperative pain management is essential in lumbar spine surgery to improve patient comfort and recovery. Traditional pain assessment methods rely on subjective scales, such as the Visual Analog Scale (VAS). The Analgesia Nociception Index (ANI) is a non-invasive monitoring tool based on heart rate variability analysis that provides an objective assessment of the balance between nociception and analgesia.

This randomized parallel-group clinical study compares two analgesic strategies in adult patients undergoing elective lumbar spine surgery. Participants are randomly assigned using a simple lottery method to receive either ultrasound-guided bilateral erector spinae plane block (ESPB) or intravenous multimodal analgesia.

ANI values are recorded at postoperative 0, 15, 30, 45, 60, 90, 120, and 180. minutes, and at 6, 12, and 24. hours. These measurements are evaluated together with clinical pain scores, total opioid consumption within 24 hours, hemodynamic parameters, and adverse events.

The primary objective is to compare ANI values between the two groups during the early postoperative period. Secondary objectives include comparison of VAS scores, opioid requirements, and incidence of analgesia-related adverse effects.

Inclusion Criteria:

• Age between 18 and 65 years
• ASA physical status I-II
• Scheduled for elective lumbar spine surgery
• Ability to provide informed consent

Exclusion Criteria:

• Known allergy to study medications
• Coagulation disorders
• Infection at the block site
• Severe cardiovascular disease
• Pregnancy
• Inability to understand the study protocol