Complication rate of ultrasound-guided paravertebral block for breast surgery

Background and objectives Thoracic paravertebral blockade is often used as an anesthetic and/or analgesic technique for breast surgery. With ultrasound guidance, the rate of complications is speculated to be lower than when using landmark-based techniques. This investigation aimed to quantify the incidence of pleural puncture and pneumothorax following non-continuous ultrasound-guided thoracic paravertebral blockade for breast surgery. Methods Patients who received thoracic paravertebral blockade for breast surgery were identified by retrospective query of our institution's electronic database over a 5-year period. Data collected included patient demographics, level of block, type and volume of local anesthetic, occurrence of pleural puncture, occurrence of pneumothorax, evidence of local anesthetic toxicity, and patient vital signs. The incidence of block complications, including pleural puncture, pneumothorax, and local anesthetic toxicity, were ascertained. Results 529 patients underwent 2163 thoracic paravertebral injections. Zero pleural punctures were identified during block performance; however, two patients were found to have a pneumothorax on postoperative chest X-ray (3.6 per 1000 surgeries, 95% CI 0.5 to 13.6; 0.9 per 1000 levels blocked, 95% CI 0.1 to 3.3). There were no cases of local anesthetic systemic toxicity or associated lipid emulsion therapy administration. Conclusions Pneumothorax following non-continuous ultrasound-guided thoracic paravertebral block using a parasagittal approach is an uncommon occurrence, with a similar rate to pneumothorax following breast surgery alone.