What are the guidelines for performing a cervical C6 (sixth cervical) nerve block with local anesthetic (e.g. bupivacaine or lidocaine) and corticosteroid (e.g. triamcinolone), guided by X-ray, in an adult patient, likely between 18 and 80 years old, with cervical radiculopathy or other condition causing pain in the cervical spine, who has failed conservative management?

Cervical C6 Nerve Block: Technical Guidelines and Safety Considerations

Primary Recommendation

Cervical C6 selective nerve root blocks with local anesthetic and corticosteroid under fluoroscopic guidance should be performed with meticulous attention to needle positioning, real-time contrast visualization, and immediate availability of emergency resuscitation equipment due to the risk of catastrophic complications including spinal cord infarction, high spinal anesthesia, and death. 1, 2, 3

Image Guidance Requirements

Fluoroscopic guidance is mandatory for transforaminal cervical nerve blocks to confirm correct needle position and contrast spread before injecting therapeutic substances 1. The procedure requires:

• Anteroposterior view verification: Needle placement should be no more medial than halfway across the width of the articular pillar to prevent central canal penetration 2
• Real-time fluoroscopy during contrast injection: Static images alone are insufficient, as subdural spread may occur without immediate visualization 2
• Continuous monitoring throughout injection: Needle position must be reconfirmed before local anesthetic administration, as needle migration can occur between contrast and therapeutic injections 2

Medication Selection and Dosing

Local Anesthetic

Bupivacaine or lidocaine are appropriate choices, with specific dosing constraints 4:

• Maximum bupivacaine dose: 175 mg without epinephrine or 225 mg with epinephrine 1:200,000 4
• Typical volume for selective nerve root block: 1.5 mL of 1.0% lidocaine or equivalent bupivacaine concentration 2, 5
• Incremental injection technique required: Inject slowly with frequent aspiration to avoid intravascular injection 4

Corticosteroid

Triamcinolone is the most commonly used corticosteroid for cervical nerve blocks 3, 5:

• Standard dose: 80 mg triamcinolone mixed with local anesthetic 5
• Total injection volume: Typically 6 mL solution when combined with local anesthetic for epidural approach 5

Critical Safety Protocols

Pre-Procedure Requirements

Emergency resuscitation equipment must be immediately available 1, 4:

• Oxygen supply and suction equipment 1
• Airway management equipment appropriate for emergency intubation 2
• Cardiovascular support medications and defibrillator 1
• Functioning intravenous access established before the procedure 4

Aspiration Testing

Negative aspiration does not guarantee against intravascular or intrathecal injection 4. Therefore:

• Perform aspiration before and during each injection 4
• Use test dose with epinephrine (10-15 mcg) when clinically appropriate to detect intravascular injection 4
• Monitor heart rate for 45 seconds post-test dose for epinephrine response (≥20 bpm increase) 4

Needle Positioning Verification

Confirm needle position in multiple fluoroscopic views 2:

• Obtain anterior oblique view of the target intervertebral foramen initially 2
• Verify anteroposterior positioning before each injection, not just during contrast phase 2
• Ensure needle tip remains in the posterior-caudal aspect of the intervertebral foramen 2

Catastrophic Complications and Recognition

Spinal Cord Infarction

Fatal cervical anterior spinal artery syndrome can occur from impaired perfusion of the major feeding anterior radicular artery 3:

• Results from injection of local anesthetic and corticosteroid around the nerve root 3
• Can occur even with seemingly uneventful procedures 3
• No reliable method exists to completely prevent this complication 2, 3

High Spinal/Subdural Injection

Immediate recognition and treatment of high spinal anesthesia is critical 2:

• Symptoms develop within seconds to minutes: Acute flaccid paralysis, respiratory difficulty, loss of consciousness, uncoordinated breathing 2
• Emergency management: Immediate airway control, ventilation support, cardiovascular support 2
• Recovery timeline: Typically 20 minutes with appropriate support, though permanent injury can occur 2, 3

Monitoring Requirements

Continuous monitoring during and immediately after injection 4:

• Cardiovascular vital signs (heart rate, blood pressure) 4
• Respiratory adequacy and ventilation 4
• Patient consciousness and neurological status 4
• Record parameters at least every 5 minutes during deep sedation or continuously if sedation used 1

Patient Selection Considerations

Appropriate Candidates

Cervical nerve blocks are indicated for 1, 6:

• Radicular pain or radiculopathy that has failed conservative management 1, 6
• Diagnostic confirmation of pain generator when clinical examination is equivocal 7
• Part of multimodal treatment regimen, not standalone therapy 1, 6

Contraindications

Absolute contraindications include 4:

• Allergy to amide local anesthetics 4
• Active infection at injection site 4
• Patient refusal or inability to cooperate 4

Relative contraindications requiring dose adjustment 4:

• Elderly or debilitated patients (reduce dose) 4
• Cardiac disease or heart block (use with caution) 4
• Liver disease (reduce dose due to impaired metabolism) 4
• Hypotension (use with caution) 4

Special Warnings

Sulfite Sensitivity

Bupivacaine with epinephrine 1:200,000 contains sodium metabisulfite, which can cause severe allergic reactions including anaphylaxis, particularly in asthmatic patients 4. Use preservative-free formulations without epinephrine in sulfite-sensitive patients 4.

Pediatric Patients

Cervical nerve blocks are not recommended for patients younger than 12 years due to insufficient safety data 4.

Pregnancy Considerations

Avoid NSAIDs and use caution with corticosteroids in pregnant patients, though single-dose dexamethasone appears acceptable in asymptomatic patients 1.

Expected Outcomes

Treatment success rates for cervical epidural steroid injection 5:

• 93% at 1 month post-injection 5
• 86% at 3 months post-injection 5
• 72% at 6 months post-injection 5

Most patients with cervical radiculopathy improve with conservative management (75-90% success rate), making nerve blocks part of a broader treatment strategy rather than definitive therapy 8, 6.

Documentation Requirements

Mandatory documentation includes 1:

• Name, route, site, time, and dosage of all drugs administered 1
• Continuous oxygen saturation and heart rate monitoring 1
• Parameters recorded at minimum every 5-10 minutes 1
• Fluoroscopic images confirming needle position and contrast spread 1