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Thoracic Paravertebral Block

Title
Ultrasound-guided paravertebral puncture and placement of catheters in human cadavers: an imaging study
Authors
Luyet C, Eichenberger U, Greif R, et al.
Journal
British Journal of Anaesthesia 2009 Apr;102(4):534-9. (Advance Access)

 

Study Summary

 

Study design
  • Observational, descriptive study in cadavers
Patient population
  • 10 embalmed adult cadavers; bilateral punctures performed (total 20 cases).
Intervention
  • The pleura and the superior costotransverse ligament, representing the anterior and posterior boundaries of the paravertebral space respectively, were visualized with a curved array 2-5MHz transducer
  • An 18 G Tuohy needle was inserted in-plane with the transducer in a lateral-to-medial direction into the paravertebral space and the space was dilated with 15mL of normal saline
  • A catheter was introduced 5cm beyond the needle tip and 10mL of contrast dye was injected.
  • A CT scan was performed to assess the spread of contrast.
Comparator(s)
  • None
Main findings
  • The thoracic paravertebral space, and subsequent needle insertion into the space, was easily visualized using the approach described.
  • The authors found it difficult to insert a catheter in the majority of patients. The distribution of contrast was mainly epidural in 6/20 cases, and in the posterior mediastinum in 2/20 cases.

 

Comments on the study

  • This is an important paper for practitioners of thoracic paravertebral block. It describes a simple approach to ultrasonographic visualization and guided needle puncture of the thoracic paravertebral space.
  • It should be noted though that they found it difficult to advance a catheter into the space; the reason for this difficulty is not clear. The precise location of the catheter tip was not evident from the CT scan and the authors did not attempt to determine this by subsequent dissection.
  • Contrast injection suggests that there is a high probability of migration of the catheter tip out of the paravertebral space.
  • We therefore concur with the authors’ opinion that their described technique is best suited at present to a single-shot thoracic paravertebral block. Clinical studies confirming its feasibility and utility in patients are eagerly awaited. However, the optimal technique for insertion of paravertebral catheters, as well as their risk-benefit ratio, remains to be determined.