Ultrasound-Guided Intermediate Cervical Plexus Block for Postoperative Analgesia in Vagus Nerve Stimulation Surgery

Effects of Ultrasound-Guided Intermediate Cervical Plexus Block on Postoperative Analgesia and Opioid Consumption in Vagus Nerve Stimulation Surgery: A Prospective Randomized Controlled Trial

This prospective, randomized, double-blind, placebo-controlled clinical trial aims to evaluate the analgesic efficacy of ultrasound-guided intermediate cervical plexus block (ICB) in patients undergoing vagus nerve stimulation (VNS) implantation surgery under general anesthesia. Participants are randomly assigned to receive either an ultrasound-guided ICB with 10 mL of 0.25% bupivacaine or a placebo injection with 10 mL of normal saline following induction of general anesthesia. The primary outcome is total postoperative morphine consumption during the first 24 hours after surgery. Secondary outcomes include intraoperative remifentanil consumption, postoperative pain intensity assessed using the Numeric Rating Scale (NRS), time to first analgesic request, length of hospital stay, and postoperative seizure incidence.

Study Overview

• Status: Completed
• Conditions: Epilepsy; Vagus Nerve Stimulation; Drug-Resistant Epilepsy
• Intervention / Treatment: Procedure: Ultrasound-guided intermediate cervical plexus block; Drug: Bupivacaine; Drug: Sodium Chloride 0.9% in 10 ml injection

Detailed Description

Postoperative pain following vagus nerve stimulation (VNS) implantation surgery originates from both cervical and infraclavicular surgical incisions. Although opioid analgesics are commonly used for postoperative pain control, minimizing opioid exposure is particularly desirable in patients with drug-resistant epilepsy because opioid-related adverse effects may delay recovery and potentially influence neurological assessment.

The intermediate cervical plexus block (ICB) is an ultrasound-guided regional anesthesia technique that provides sensory blockade of the superficial branches of the cervical plexus while allowing accurate deposition of local anesthetic between the investing and prevertebral layers of the deep cervical fascia. Previous studies have demonstrated the effectiveness of cervical plexus blocks in various cervical surgical procedures; however, evidence regarding their use during VNS implantation surgery remains limited.

This prospective, randomized, double-blind, placebo-controlled study compares ultrasound-guided ICB using 10 mL of 0.25% bupivacaine with a placebo injection of 10 mL normal saline administered after induction of general anesthesia. The primary objective is to determine whether ICB reduces postoperative opioid requirements during the first 24 hours after surgery. Secondary objectives include evaluation of intraoperative remifentanil consumption, postoperative pain scores, time to first rescue analgesic, length of hospital stay, and postoperative seizure incidence. The findings are expected to provide evidence regarding the effectiveness and safety of ultrasound-guided intermediate cervical plexus block as part of multimodal analgesia for patients undergoing VNS implantation surgery.

• Study Type: Interventional
• Enrollment (Actual): 52
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Elâzığ
    • Elâzığ, Elâzığ, Turkey (Türkiye), 23100
      • Fırat University Faculty of Medicine Hospital

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adults aged 18-60 years
• American Society of Anesthesiologists (ASA) physical status II-III
• Drug-resistant epilepsy
• Scheduled for elective vagus nerve stimulation implantation surgery under general anesthesia
• Written informed consent obtained

Exclusion Criteria:

• Allergy or contraindication to local anesthetics
• Coagulopathy or current anticoagulant therapy
• Infection at the injection site
• Pregnancy or breastfeeding
• Severe pulmonary disease
• Inability to understand or use the Numeric Rating Scale (NRS)
• Refusal to participate

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intermediate Cervical Plexus Block; Participants received an ultrasound-guided intermediate cervical plexus block with 10 mL of 0.25% bupivacaine after induction of general anesthesia before vagus nerve stimulation implantation surgery.	Procedure: Ultrasound-guided intermediate cervical plexus block; Ultrasound-guided intermediate cervical plexus block performed after induction of general anesthesia.; Drug: Bupivacaine; 10 mL of 0.25% bupivacaine administered during ultrasound-guided intermediate cervical plexus block.
Placebo Comparator: Control; Participants received an ultrasound-guided placebo injection with 10 mL of 0.9% normal saline after induction of general anesthesia before vagus nerve stimulation implantation surgery.	Procedure: Ultrasound-guided intermediate cervical plexus block; Ultrasound-guided intermediate cervical plexus block performed after induction of general anesthesia.; Drug: Sodium Chloride 0.9% in 10 ml injection; 10 mL of 0.9% sodium chloride administered as a placebo injection under ultrasound guidance.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total postoperative morphine consumption during the first 24 hours after surgery	Total cumulative intravenous morphine consumption during the first 24 hours after vagus nerve stimulation implantation surgery, recorded in milligrams (mg).	24 hours after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraoperative remifentanil consumption	Total intraoperative remifentanil consumption recorded in micrograms (µg) from induction of anesthesia until completion of surgery.	From induction of anesthesia until the end of surgery
Postoperative pain intensity	Pain intensity was assessed using the Numeric Rating Scale (NRS; 0 = no pain, 10 = worst imaginable pain) at PACU admission, 30 minutes after PACU admission, and at postoperative 1, 6, 12, and 24 hours.	From admission to the post-anesthesia care unit (PACU) through 24 hours postoperatively
Time to first rescue analgesic request	Time from arrival in the post-anesthesia care unit (PACU) until the first administration of rescue analgesia, measured in minutes.	Within 24 hours after surgery
Length of hospital stay	Time to first rescue analgesic request was defined as the time from PACU arrival to the first request or administration of rescue analgesia. Patients who did not require rescue analgesia within 24 hours were censored at 24 hours.	From arrival in the post-anesthesia care unit (PACU) until the first rescue analgesic request, assessed up to 24 hours postoperatively
Postoperative seizure incidence	Occurrence of clinically observed postoperative seizure episodes during the first 24 postoperative hours.	Within 24 hours after surgery

Collaborators and Investigators

• Sponsor: Firat University
• Investigators: Principal Investigator: Ahmet Aksu, Assistant Professor, Fırat University Faculty of Medicine Department of Anaesthesiology and Reanimation

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2022
• Primary Completion (Actual): May 1, 2023
• Study Completion (Actual): May 31, 2023

Study Registration Dates

• First Submitted: June 30, 2026
• First Submitted That Met QC Criteria: July 7, 2026
• First Posted (Actual): July 8, 2026

Study Record Updates

• Last Update Posted (Actual): July 8, 2026
• Last Update Submitted That Met QC Criteria: July 7, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Epilepsy; Regional Anesthesia; Vagus Nerve Stimulation; Pain, Postoperative; Analgesics, Opioid; Cervical Plexus Block
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Drug Resistant Epilepsy; Pain, Postoperative; Epilepsy; Organic Chemicals; Therapeutics; Drug Administration Routes; Drug Therapy; Anilides; Amides; Aniline Compounds; Amines; Inorganic Chemicals; Chlorine Compounds; Sodium Compounds; Chlorides; Hydrochloric Acid; Bupivacaine; Injections; Sodium Chloride
• Other Study ID Numbers: 7996

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: De-identified individual participant data underlying the results reported in this study will be made available upon reasonable request to the corresponding author, following publication, subject to institutional approval and applicable ethical and legal requirements.

Drug and device information, study documents

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