Somatic paravertebral nerve blockade. Incidence of failed block and complications.

The failure rate and complications following thoracic and lumbar paravertebral blocks performed in 620 adults and 42 children were recorded. The technique failure rate in adults was 6.1%. No failures occurred in children. The complications recorded were: inadvertent vascular puncture (6.8%); hypotension (4.0%); haematoma (2.4%); pain at site of skin puncture (1.3%); signs of epidural or intrathecal spread (1.0%); pleural puncture (0.8%); pneumothorax (0.5%). No complications were noted in the children. The use of a bilateral paravertebral technique was found approximately to double the likelihood of inadvertent vascular puncture (9% vs. 5%) and to cause an eight-fold increase in pleural puncture and pneumothorax (3% vs. 0.4%), when compared with unilateral blocks. The incidence of other complications was similar between bilateral and unilateral blocks.