What is the technique for a thoracic transforaminal epidural injection?

Technique for Thoracic Transforaminal Epidural Injection

The thoracic transforaminal epidural injection technique requires careful fluoroscopic guidance and precise needle placement to maximize efficacy while minimizing risks of serious complications such as pneumothorax or neurovascular injury. Based on available evidence, this procedure should be approached with caution as it has shown limited efficacy for pain management with success rates lower than cervical or lumbar regions 1.

Patient Positioning and Setup

• Position patient prone on fluoroscopy table
• Place pillows under chest and abdomen to reduce thoracic kyphosis
• Ensure C-arm is available for anteroposterior (AP) and lateral imaging

Procedural Technique

Step 1: Target Identification

• Obtain AP fluoroscopic view of thoracic spine at target level
• Identify the thoracic neural foramen at the affected level
• Use the rib as a landmark and conduit to safely access the foramen 2

Step 2: Needle Entry and Advancement

• Mark skin entry point at the superior aspect of the rib that forms the inferior border of the target foramen
• After sterile preparation and local anesthesia:
  • Use a 22-gauge spinal needle
  • Direct the needle to contact the superior aspect of the rib
  • "Walk" the needle along the rib toward the neural foramen
  • This rib-hugging technique helps avoid pneumothorax 2

Step 3: Final Needle Positioning

• Advance needle under intermittent fluoroscopic guidance until needle tip reaches the posterior aspect of the foramen
• Confirm position with lateral view - needle tip should be in the posterior aspect of the foramen
• Avoid advancing too deep into the foramen to prevent potential injury to thoracic nerve roots or vasculature

Step 4: Contrast Administration and Confirmation

• Inject 0.5-1 ml of non-ionic contrast medium under live fluoroscopy
• Confirm proper epidural spread pattern:
  • Contrast should outline the nerve root and spread into the epidural space
  • Note that 3 ml of contrast typically spreads approximately 6 levels (3 cephalad, 2 caudad) 3
  • Contrast should demonstrate both ventral and dorsal epidural spread in most cases (88%) 3
• Ensure no intravascular uptake is observed

Step 5: Medication Administration

• After confirming proper needle placement, inject the therapeutic medication:
  • Typically 1-3 ml total volume of steroid and local anesthetic mixture
  • Common mixture: methylprednisolone or triamcinolone with bupivacaine or ropivacaine

Important Considerations and Precautions

Anatomical Challenges

• Thoracic spine has unique anatomical considerations compared to lumbar region:
  • Narrower neural foramina
  • Proximity to pleura and lungs
  • Presence of ribs as both landmarks and obstacles
  • Risk of pneumothorax if needle deviates anteriorly

Potential Complications

• Pneumothorax (most significant risk - use rib-hugging technique to minimize) 2
• Neurovascular injury
• Dural puncture
• Intravascular injection
• Infection
• Vasovagal response

Efficacy Considerations

• Success rates for thoracic TFESI appear lower than for cervical or lumbar regions
• Only approximately 30% of patients achieve ≥50% pain relief 1
• Better outcomes may be seen in patients with disc herniation (36% success) versus degenerative stenosis (21% success) 1
• Consider alternative approaches if this technique fails

Post-Procedure Care

• Monitor patient for at least 30 minutes after the procedure
• Assess for signs of pneumothorax or other complications
• Provide discharge instructions regarding potential delayed complications
• Schedule appropriate follow-up (typically 2-3 weeks)

This technique requires significant expertise in spinal interventions and thorough knowledge of thoracic spine anatomy. The procedure should be performed by physicians with specific training in thoracic interventional procedures under appropriate fluoroscopic guidance.