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The thoracic paravertebral block, with or without catheter, can be used in lieu of thoracic epidural catheter for unilateral procedures and for breast surgeries.
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Pneumothorax is the major complication of this block.
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When performing the block and the injection, make sure the needle tip always remains visible in the plane.
Indications
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Thoracic paravertebral catheter can be used in lieu of thoracic epidural analgesia for unilateral procedures like thoracotomies, nephrectomies (either partial or radical), rib fractures, and breast surgeries.
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This block is used in cases where epidural catheter is difficult or epidural analgesia failed, for unilateral procedures.
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Bilateral paravertebral blocks, with or without catheter insertion, can be used for bilateral procedures taking care to avoid the development of bilateral pneumothoraces and local anesthetic overdose toxicity.
Contraindications
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The same contraindications exist as with epidural catheter insertions regarding the use of anticoagulants and antiplatelet drugs.
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Pneumothorax is the main complication of thoracic paravertebral block, with or without catheter insertion. Therefore, inexperience performing regional anesthesia using ultrasound is considered a relative contraindication for thoracic paravertebral block.
Sonoanatomy
The thoracic paravertebral space lies adjacent to the thoracic spine bodies and contains the spinal nerves as they emerge from the intervertebral foramina, the anterior divisions (intercostal nerves), the posterior divisions, and the rami communicantes. The thoracic paravertebral space is sandwiched between the parietal pleura anteriorly and the superior costotransverse ligament posteriorly. The vertebral body, intervertebral disc, and intervertebral foramen form the medial boundary. The thoracic paravertebral space is connected to the level above and below, with the caudad limit being the origin of the psoas major at T12.
The thoracic paravertebral space can be scanned in both the transverse (intercostal) and paramedian approaches. In the transverse approach, the probe is aligned in the space between two adjacent ribs overlying the transverse process. In this approach, the external intercostal muscle, internal intercostal membrane that binds medially with the costotransverse ligament, and the parietal pleura can be viewed. The landmarks in this scan are the bony reflections from the transverse process, with its dropout shadow, and the pleural reflection, which moves with respiration.
In the paramedian (longitudinal) approach, the probe lies in the paramedian plane of the transverse processes. The main landmarks in this approach are reflections and dropout from the tips of the transverse processes. The external intercostal muscle and costotransverse ligament lie between the transverse processes. The parietal pleura lie deep to these layers and can be recognized by their movement with respiration as evidenced in ultrasound by characteristic sliding and comet tails signs ( Fig. 33.1 ).
