Minimum Effective Dose of Ropivacaine for Ultrasound-guided Interscalene Block

Minimum Effective Dose of Ropivacaine 0.5% for Ultrasound-guided Interscalene Block Targeting the C7 Nerve Root in Hand and Forearm Surgery

Inter muscular groove brachial plexus block is a commonly used peripheral nerve block technique in clinical practice, commonly used for anesthesia and analgesia in clavicle, shoulder, and humeral surgeries. The classic ultrasound-guided intermuscular groove block also involves puncturing the needle to the level of the C5/C6 anterior branch for drug injection. After injection, local anesthetics mainly wrap around C5, C6, and some C7 nerve roots. Therefore, intermuscular groove block is mainly used for shoulder, humerus, and clavicle surgery. Due to incomplete ulnar block, it is not recommended for surgery on the elbow joint and its distal end.Scholars have found that using C5 as the puncture target to implement intermuscular groove block and administering 10ml of 0.75% ropivacaine, the success rate of ulnar nerve block is 19%. The success rate of ulnar nerve block with C6 as the puncture target was 93% when 10ml of 0.75% ropivacaine was administered. This suggests that blockade methods closer to the tail muscle groove on the tail side have a higher success rate for blocking the C7, C8, and T1 nerve roots. In our clinical work, the investigators found that when performing intermuscular groove block with C7 nerve root as the puncture target, local anesthetics not only stably wrap around C7 nerve root, but also spread to wrap around C5 and C6 nerve roots on the head side, and spread to the deep surface of the brachial plexus trunk on the tail side. Local anesthetic diffusion can also be seen in some patients at the brachial plexus bundle in the intercostal space. From the perspective of local anesthetic diffusion patterns, intermuscular groove block targeting the C7 nerve root may cover the anterior branches of C5, C6, C7, C8, and T1 nerve roots, achieving complete brachial plexus block. Preliminary clinical practice suggests that C7 intermuscular groove block can be used for forearm and hand surgery. Successful C7 intermuscular groove block relies on the diffusion and wrapping of local anesthetics around the anterior branches of C5, C6, and C7 nerve roots, as well as the inferior trunk of the brachial plexus (or the anterior branches of C8 and T1 nerve roots).Therefore, the investigators designed this study to determine the amount of local anesthetic required to achieve stable forearm and hand block during C7 intermuscular groove block.

Study Overview

• Status: Recruiting
• Conditions: Hand and Forearm Trauma; Hand and Forearm Diseases
• Intervention / Treatment: Procedure: Ultrasound guided intermuscular groove block targeting the C7 nerve root; Procedure: Ultrasound guided intermuscular groove block targeting the C7 nerve root

Detailed Description

Inter muscular groove brachial plexus block is a commonly used peripheral nerve block technique in clinical practice, commonly used for anesthesia and analgesia in clavicle, shoulder, and humeral surgeries. Intermuscular groove block is achieved by injecting local anesthetics between the anterior and middle scalene muscles in order to block the anterior branches of the cervical nerve that pass through this gap, including the anterior branches of the cervical 5 (C5), cervical 6 (C6), and cervical 7 (C7) spinal nerves. The classic technique of intermuscular groove block involves puncturing the thyroid cartilage horizontally into the intermuscular groove. This area is roughly equivalent to the level of the anterior branch of the C5/C6 nerve root. The classic ultrasound-guided intermuscular groove block also involves puncturing the needle to the level of the C5/C6 anterior branch for drug injection. After injection, local anesthetics mainly wrap around C5, C6, and some C7 nerve roots. According to the range of spinal nerve innervation, its blocking range is located in the shoulder, the anterior, posterior, and lateral sides of the upper arm, the anterior, posterior, and lateral sides of the forearm, and the two and a half fingers on the radial side. Therefore, intermuscular groove block is mainly used for shoulder, humerus, and clavicle surgery. Due to incomplete ulnar block, it is not recommended for surgery on the elbow joint and its distal end.Scholars have found that using C5 as the puncture target to implement intermuscular groove block and administering 10ml of 0.75% ropivacaine, the success rate of ulnar nerve block is 19%. The success rate of ulnar nerve block with C6 as the puncture target was 93% when 10ml of 0.75% ropivacaine was administered. This suggests that blockade methods closer to the tail muscle groove on the tail side have a higher success rate for blocking the C7, C8, and T1 nerve roots. In our clinical work, the investigators found that when performing intermuscular groove block with C7 nerve root as the puncture target, local anesthetics not only stably wrap around C7 nerve root, but also spread to wrap around C5 and C6 nerve roots on the head side, and spread to the deep surface of the brachial plexus trunk on the tail side. Local anesthetic diffusion can also be seen in some patients at the brachial plexus bundle in the intercostal space. From the perspective of local anesthetic diffusion patterns, intermuscular groove block targeting the C7 nerve root may cover the anterior branches of C5, C6, C7, C8, and T1 nerve roots, achieving complete brachial plexus block. In the preliminary exploratory clinical work, the patient underwent C7 nerve root intermuscular groove brachial plexus block. Through sensory testing, it was found that the musculocutaneous nerve, medial forearm nerve, radial nerve, median nerve, and ulnar nerve could all be stably blocked, and the forearm and hand surgeries were successfully completed under nerve block. Preliminary clinical practice suggests that C7 intermuscular groove block can be used for forearm and hand surgery. Successful C7 intermuscular groove block relies on the diffusion and wrapping of local anesthetics around the anterior branches of C5, C6, and C7 nerve roots, as well as the inferior trunk of the brachial plexus (or the anterior branches of C8 and T1 nerve roots).Therefore, the investigators designed this study to determine the amount of local anesthetic required to achieve stable forearm and hand block during C7 intermuscular groove block.

• Study Type: Interventional
• Enrollment (Estimated): 56
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Huailiang LI,; Phone Number: 86+18834183517; Email: 574199674@qq.com
• Study Contact Backup: Name: Zheng Hua, Study Principal Investigator; Phone Number: 86+18672750530

Study Locations

• China
  • Shanxi
    • Taiyuan, Shanxi, China, 030032
      • Recruiting
      • Shanxi Bethune Hospital
      • Contact: Xiaomin zhang; Phone Number: 8618435148730; Email: sxdyyky@126.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age range: 18-60 years old
• ASAⅠ~II
• BMI between 18 and 30kg/m2
• Patients undergoing hand or forearm surgery
• Sign informed consent form

Exclusion Criteria:

• Refusal to participate in the experiment
• Merge peripheral nerve diseases
• Lidocaine and ropivacaine allergy
• Pregnant women
• Obstructive or restrictive lung disease
• Coagulation dysfunction
• Long term use of opioid drugs
• Infection, tumor or surgical history at the puncture site

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Deceasing; Brachial plexus block with decreasing dose. Real time ultrasound-guided intermuscular brachial plexus block anesthesia targeting the C7 nerve root.	Procedure: Ultrasound guided intermuscular groove block targeting the C7 nerve root; The patient will receive ultrasound-guided intermuscular groove brachial plexus block targeting the C7 nerve root, decreasing doses of ropivacaine 0.5% will be administered.; Procedure: Ultrasound guided intermuscular groove block targeting the C7 nerve root; The patient will receive ultrasound-guided intermuscular groove brachial plexus block targeting the C7 nerve root, similar doses of ropivacaine 0.5% will be administered.
Experimental: similar; Brachial plexus block, with similar doses. Real time ultrasound-guided intermuscular brachial plexus block anesthesia for C7 nerve roots	Procedure: Ultrasound guided intermuscular groove block targeting the C7 nerve root; The patient will receive ultrasound-guided intermuscular groove brachial plexus block targeting the C7 nerve root, decreasing doses of ropivacaine 0.5% will be administered.; Procedure: Ultrasound guided intermuscular groove block targeting the C7 nerve root; The patient will receive ultrasound-guided intermuscular groove brachial plexus block targeting the C7 nerve root, similar doses of ropivacaine 0.5% will be administered.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Assessment of blocking effect	Starting from the completion of the nerve block, an independent evaluator (unaware of the dosage used) will test and record the block effect at 10, 20, and 30 minutes after the block. The block effect will be judged based on the effect at 30 minutes. Conduct sensory tests on the skin innervated by various nerves using ice cubes. Use a 3-point numerical scale (0=normal cold sensation, no obstruction; 1=partial cold sensation, partial obstruction; 2=no cold sensation, complete obstruction). Radial nerve, median nerve, ulnar nerve, musculocutaneous nerve, and medial forearm cutaneous nerve. Evaluate the degree of motor block through specific exercise activities (0=normal activity, 1=partial block, 2=complete block). Patients who are fully awake or have been administered an appropriate amount of sedatives, maintain spontaneous breathing, and successfully complete the surgery are considered to have successful blockade (i.e. positive reaction).	From the completion of nerve block to the 30th minute after block

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diaphragmatic muscle movement status	Ultrasound measurement of basal range of motion of the blocked ipsilateral diaphragm: The patient is seated in a semi seated position, with a low-frequency convex array probe placed between the anterior axillary line and the midline of the axilla. Real time M-mode ultrasound is used to evaluate the motion of the ipsilateral diaphragm. Use a low intercostal or subcostal approach, with the liver or spleen as the sound window for scanning. Record the diaphragm movement amplitude during rapid nasal inhalation from the resting exhalation position. Measure three times and take the average. And retain the measured images. 30 minutes after the completion of nerve block, evaluate the patient's diaphragm movement using the same method as before. The degree of diaphragmatic block is defined as a decrease in movement amplitude of>75% (complete diaphragmatic block), a decrease in movement amplitude of 25-75% (partial block), and a decrease of<25% (no block) compared to before the block was impleme	From the completion of nerve block to the 30th minute after block

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Complications of nerve block	The evaluator also records the occurrence of complications such as hypersensitivity, vascular injury, recurrent laryngeal nerve block, Horner's syndrome, and local anesthetic poisoning during the blocking process.	From the completion of nerve block to the 30th minute after block

Collaborators and Investigators

• Sponsor: Huazhong University of Science and Technology

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: December 22, 2025
• First Submitted That Met QC Criteria: December 24, 2025
• First Posted (Actual): January 8, 2026

Study Record Updates

• Last Update Posted (Actual): April 3, 2026
• Last Update Submitted That Met QC Criteria: March 30, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Minimum effective dose; ultrasound-guided interscalene block; C7 nerve root
• Other Study ID Numbers: YXLL-2025-292

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Paper case report forms were written by hand

Drug and device information, study documents

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