Efficacy of the C8 Nerve Root Block During Interscalene Block for Anesthesia of the Posterior Aspect of the Shoulder

Study Overview
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Brief Summary
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This study evaluates the effects of selective 8th cervical nerve root block during interscalene brachial plexus block on the relief of pain intensity upon the introduction of a posterior portal during arthroscopic shoulder surgery. The 5th to 7th cervical nerve roots will be blocked in half of participants, while the 5th to 8th cervical nerve roots will be blocked in the other half.

Detailed Description
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By blocking only the 5th to 7th cervical nerve blocks, conventional interscalene brachial plexus block spares the 8th cervical and 1st thoracic dermatomes which innervate the posterior aspect of the shoulder. To visualize the shoulder joint space during shoulder arthroscopic surgery, the introduction of a posterior portal is essential. However, conventional interscalene brachial plexus block cannot effectively relieve the pain caused by its insertion due to sparing of the 8th cervical and 1st thoracic dermatomes. The addition of the 8th cervical nerve root block to conventional interscalene brachial plexus block decreases pain intensity upon the introduction of a posterior portal.

Official Title
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Efficacy of the 8th Cervical Nerve Root Block During Interscalene Brachial Plexus Block for Arthroscopic Shoulder Surgery: Prospective Randomized Controlled Study

Conditions
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Brachial Plexus Block, Shoulder Pain

Intervention / Treatment
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* Procedure: Conventional interscalene block
* Procedure: Interscalene block with C8 root block
* Drug: 0.75% ropivacaine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists physical status 1 and 2 Arthroscopic shoulder surgery under interscalene brachial plexus block Exclusion Criteria: Patient refusal Contralateral hemidiaphragmatic paralysis or paresis Contralateral vocal cord palsy Severe pulmonary restrictive disease Coagulopathy Allergy to local anesthetics or history of allergic shock Difficulty communicating with medical personnel Peripheral neuropathy or neurologic sequelae on the operative limb

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Interscalene block with C8 root block<br>The 5th to 8th cervical nerve root block under ultrasound guidance using 25 to 30 ml of 0.75% ropivacaine | Procedure: Interscalene block with C8 root block<br>* Under ultrasound guidance, the 5th to 8th cervical nerve roots are blocked.<br>Drug: 0.75% ropivacaine<br>* Placement of 25 to 30 ml of 0.75% ropivacaine around the cervical nerve roots<br>* Other names: Naropin;|
| Active Comparator: Conventional interscalene block<br>The 5th to 7th cervical nerve root block under ultrasound guidance using 25 to 30 ml of 0.75% ropivacaine | Procedure: Conventional interscalene block<br>* Under ultrasound guidance, the 5th to 7th cervical nerve roots are blocked.<br>Drug: 0.75% ropivacaine<br>* Placement of 25 to 30 ml of 0.75% ropivacaine around the cervical nerve roots<br>* Other names: Naropin;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain intensity upon the introduction of a posterior portal | 0, 1, and 2 represent no pain, mild pain, and severe pain, respectively. | 50 minutes after interscalene block | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensory blockade | C5 to T1 dermatomal blockade graded from 0 to 2 (0 = no cold sensation, 1 = reduced cold sensation, and 2 = normal cold sensation) by applying ice to the shoulder | 30 minutes after interscalene block | 
| Motor blockade | Motor blockade of the radial, ulnar, median, musculocutaneous, and axillary nerves graded from 0 to 2 (0 = complete block, 1 = partial block, and 2 = no block) | 30 minutes after interscalene block | 
| Ipsilateral hemidiaphragmatic blockade | Extent of a reduction in the amplitude of excursion of the diaphragm on the vertical axis of the M-mode wave under M-mode ultrasound evaluation | Before interscalene block and 30 minutes after interscalene block | 
| Horner's syndrome | The extent of a reduction in the ipsilateral pupil size measured by a pupillometer Presence or absence of ptosis | Before interscalene block and 30 minutes after interscalene block | 
| Pulmonary function test | Forced expiratory volume at one second (FEV1) and FEV1/forced vital capacity before and 30 minutes after the end of local anesthetic injection | Before interscalene block and 30 minutes after interscalene block | 
| Complications related with interscalene block | Presence or absence of vascular puncture, local anesthetic systemic toxicity, pneumothorax, and paresthesia | 24 hours | 
| Numerical pain rating score at admission to postanesthetic care unit | Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) at admission to postanesthetic care unit | 5 minutes | 
| Numerical pain rating score at discharge from postanesthetic care unit | Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) at discharge from postanesthetic care unit | 30 minutes | 
| Numerical pain rating score between 6 and 12 hours after surgery | Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) between 6 and 12 hours after surgery | 6 and 12 hours | 
| Numerical pain rating score 24 hours after surgery | Numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) 24 hours after surgery | 24 hours | 
| Worst numerical pain rating score | Worst numerical pain rating score ranging from 0 to 10 (0 = no pain, 10 = worst pain imaginable) during 24 hours after surgery | 24 hours | 
| Postoperative hour when pain starts to be felt | Time at regression of anesthesia which starts to cause postoperative pain during 24 hours after surgery | 24 hours | 
| Patient's satisfaction about surgical anesthesia and postoperative analgesia | Likert scale consisting of very dissatisfied, dissatisfied, unsure, satisfied, and very satisfied | 24 hours | 
| Dose of postoperative analgesic use | Cumulative dose of analgesic required for postoperative analgesia during 24 hours after surgery | 24 hours | 
| Frequency of postoperative analgesic use | Frequency of analgesic use during 24 hours after surgery | 24 hours | 
| Dose of intraoperative analgesic use | Cumulative dose of analgesic to supplement incomplete surgical anesthesia | 2 hours | 
| Frequency of intraoperative analgesic use | Frequency of analgesic use to supplement incomplete surgical anesthesia | 2 hours | 
| Conversion into general anesthesia | Number of patients whose regional anesthesia is converted into general anesthesia due to incomplete surgical anesthesia provided by the regional anesthesia | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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8th cervical nerve root block