Postoperative Pain Monitoring With ANI in Lumbar Spine Surgery (SPINE-ANI)

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.

Study Overview

• Status: Recruiting
• Conditions: Postoperative Pain; Lumbar Spine Surgery
• Intervention / Treatment: Procedure: Erector Spinae Plane Block; Drug: Intravenous Multimodal Analgesia

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ayşe Tekin, MD; Phone Number: +905376180290; Email: aysesstekin@gmail.com
• Study Contact Backup: Name: Neval Boztuğ, MD; Phone Number: +905327995810; Email: nboztuğ@akdeniz.edu.tr

Study Locations

• Turkey (Türkiye)
  • Antalya
    • Antalya, Antalya, Turkey (Türkiye), 0707
      • Recruiting
      • Akdeniz University Faculty of Medicine Hospital
      • Contact: Ayşe Tekin, MD; Phone Number: +905376180290; Email: aysesstekin@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Erector Spinae Plane Block; Ultrasound-guided bilateral erector spinae plane block performed at the thoracolumbar level using a total of 200 mg bupivacaine for postoperative analgesia.	Procedure: Erector Spinae Plane Block; Ultrasound-guided bilateral erector spinae plane block performed at the thoracolumbar level using a total of 200 mg bupivacaine for postoperative analgesia.
Active Comparator: Intravenous Multimodal Analgesia; Intravenous multimodal analgesia including paracetamol 1 g, morphine 0.1 mg/kg, dexamethasone 8 mg, and ketamine 0.5 mg/kg bolus followed by 0.3 mg/kg/h infusion.	Drug: Intravenous Multimodal Analgesia; Intravenous administration of paracetamol 1 g, morphine 0.1 mg/kg, dexamethasone 8 mg, and ketamine 0.5 mg/kg bolus followed by 0.3 mg/kg/h infusion for postoperative pain management.; Other Names: IV Multimodal Analgesia

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Analgesia Nociception Index (ANI)	Analgesia Nociception Index (ANI) measured using the ANI monitor. The ANI ranges from 0 to 100. Higher values indicate greater parasympathetic tone and lower nociceptive stimulation, whereas lower values indicate higher nociceptive stimulation.	From 0 minutes to 24 hours postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Analog Scale (VAS) Pain Score	Pain intensity assessed using the Visual Analog Scale (VAS), ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate worse pain.	From 0 minutes to 24 hours postoperatively
Postoperative Nausea	Incidence of postoperative nausea within 24 hours after surgery.	Within 24 hours postoperatively.

Collaborators and Investigators

• Sponsor: Akdeniz University Hospital
• Investigators: Principal Investigator: Neval Boztuğ, MD, Akdeniz University

Study record dates

Study Major Dates

• Study Start (Actual): December 16, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: February 25, 2026
• First Submitted That Met QC Criteria: March 3, 2026
• First Posted (Actual): March 6, 2026

Study Record Updates

• Last Update Posted (Actual): March 6, 2026
• Last Update Submitted That Met QC Criteria: March 3, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Postoperative Pain; Randomized Controlled Trial; Analgesia Nociception Index; Lumbar Spine Surgery; Erector Spinae Plane Block; Multimodal Analgesia
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative
• Other Study ID Numbers: AU-ANES-ANI-2025-360; BAP Project No: 6976 (Other Grant/Funding Number: Akdeniz University Scientific Research Projects Coordination Unit (BAP))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared due to institutional policies and patient confidentiality considerations.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No