What is the step-by-step procedure for an epidural block injection at the lumbar spine level?

Step-by-Step Procedure for Lumbar Epidural Block

The lumbar epidural block is performed under strict aseptic technique with fluoroscopic guidance to ensure proper needle placement and medication delivery, which improves accuracy, reduces complications, and increases therapeutic benefit. 1

Patient Preparation

• Position the patient in lateral decubitus position (preferred) or sitting position with back flexed to open the interlaminar spaces
• Apply standard monitors (blood pressure, pulse oximetry, ECG)
• Ensure IV access is established before procedure
• Prepare resuscitative equipment, oxygen, and emergency drugs nearby

Equipment Required

• Sterile drapes, gloves, mask, cap
• Antiseptic solution (chlorhexidine-alcohol preferred)
• Local anesthetic (1-2% lidocaine for skin infiltration)
• Epidural tray containing:
  • 17G or 18G Tuohy needle with stylet
  • Loss of resistance (LOR) syringe
  • Epidural catheter (if continuous technique planned)
  • Filter
  • Connector

Procedural Steps

1. Identify the appropriate intervertebral level:

   • Palpate the iliac crests (corresponds to L4 spinous process)
   • Count up or down to identify target level
   • Mark the site with indelible marker
   • Confirm with fluoroscopy for accuracy

2. Prepare the skin:

   • Clean with antiseptic solution in circular motion from center outward
   • Allow to dry completely
   • Drape the area to create sterile field

3. Administer local anesthetic:

   • Infiltrate skin and subcutaneous tissue at entry point
   • Infiltrate deeper tissues along intended needle path

4. Insert the Tuohy needle:

   • Introduce the needle with stylet in place at midline
   • Advance through supraspinous ligament, interspinous ligament, and ligamentum flavum
   • Remove stylet once in ligamentum flavum

5. Identify the epidural space:

   • Attach LOR syringe filled with air or saline
   • Advance needle slowly while applying constant pressure on plunger
   • Feel for sudden loss of resistance when epidural space is entered
   • Stop advancing immediately when LOR is felt

6. Confirm epidural placement:

   • Aspirate to check for absence of CSF or blood
   • If CSF appears, remove needle and attempt at different level (dural puncture occurred)
   • If blood appears, remove needle and reattempt (vascular puncture occurred)

7. Administer test dose:

   • Inject 3-5 mL of local anesthetic solution containing epinephrine (10-15 mcg)
   • Monitor for signs of intravascular injection (increased heart rate, blood pressure) or intrathecal injection (rapid onset of motor block) for 2-5 minutes 2
   • If no signs of intravascular or intrathecal injection, proceed with full dose

8. Administer therapeutic dose:

   • Inject medication slowly in incremental doses (3-5 mL at a time)
   • Aspirate before and during each injection to avoid intravascular injection
   • For steroid injections, standard dose is 40mg triamcinolone (though 20mg may provide similar relief with fewer side effects) 1

9. For continuous technique (catheter placement):

   • Thread catheter 3-5 cm into epidural space
   • Remove needle carefully while holding catheter in place
   • Secure catheter to back with transparent dressing
   • Perform test dose through catheter before administering full dose

Post-Procedure Care

• Monitor vital signs for at least 30 minutes
• Assess sensory and motor function
• Provide discharge instructions including activity limitations
• Schedule follow-up appointment

Potential Complications and Management

• Dural puncture: If CSF is aspirated, remove needle and attempt at different level. Consider intrathecal catheter placement if accidental dural puncture occurs during epidural catheter placement 3
• Intravascular injection: If test dose produces tachycardia or hypertension, remove needle and reattempt
• High/total spinal block: Can occur even with test dose. Be prepared for respiratory support, vasopressors, and airway management 4
• Post-dural puncture headache: Consider epidural blood patch if severe and persistent 3
• Hematoma or infection: Rare but serious. Follow appropriate timing guidelines for anticoagulants 3

Special Considerations

• Use ultrasound guidance for difficult anatomy or when fluoroscopy is unavailable
• For patients on anticoagulants, follow specific timing guidelines for discontinuation and resumption 3
• Ensure proper labeling of catheters, especially if intrathecal placement occurs accidentally, to prevent medication errors 3
• The lowest effective dose of local anesthetic should be used to minimize side effects 2

This procedure requires proper training and experience to perform safely and effectively. Complications, though rare with proper technique, can be serious and require immediate recognition and management.