Ultrasound-guided thoracic paravertebral blockade: a cadaveric study

Area of Science:

• Anesthesiology
• Regional Anesthesia
• Thoracic Surgery

Background:

• Paravertebral space blockade is crucial for thoracic surgery analgesia.
• Ultrasound guidance offers potential for improved efficacy and reduced complications.
• This study compares single- versus dual-injection techniques in a cadaver model.

Purpose of the Study:

• To evaluate the spread of contrast dye and catheter placement in ultrasound-guided paravertebral blockade.
• To compare single-injection versus dual-injection techniques for thoracic paravertebral blockade.

Main Methods:

• Thirty paravertebral injections and 20 catheter placements were performed on 10 fresh cadavers.
• Ultrasound-guided, in-plane needle insertion was used to inject contrast dye.
• Cadavers were dissected to assess contrast spread and catheter location.

Main Results:

• Ultrasound reliably identified the paravertebral space.
• Contrast spread to paravertebral, intercostal, and epidural spaces was observed.
• Dual-injection showed greater segmental intercostal spread (6 spaces) compared to single-injection (4.5 spaces).
• Epidural spread occurred in 40% of injections; catheters were misplaced in 40% of cases.

Conclusions:

• Transverse in-plane ultrasound guidance for thoracic paravertebral blockade is feasible and reliable.
• Paravertebral spread is variable; intercostal and epidural spread likely contribute to analgesia.
• Dual-injection may enhance dermatome coverage via increased intercostal spread.
• Catheter malposition is a concern with this technique.