Postoperative paravertebral blocks for thoracic surgery. A radiological appraisal.

Five patients who underwent thoracic operations had an extradural catheter placed in the paravertebral space. X-ray contrast was injected through the catheters. In those who had detectable analgesia, contrast spread extensively, laterally, along one intercostal space, and up and down the paravertebral spaces. In one patient, contrast appears to have entered the extradural space and, in another who had no detectable analgesia, the contrast was probably dispersed intrapleurally. The significance of these findings is discussed.