General anaesthesia versus thoracic paravertebral block for breast surgery: a meta-analysis

Thoracic paravertebral block (TPVB) offers an attractive alternative to general anaesthesia (GA) for ambulatory breast surgery. The aim of this meta-analysis was first to evaluate the safety and efficacy of TPVB for breast surgery, and second to compare TPVB with GA with regard to postoperative pain, nausea and vomiting, opioid consumption and length of hospital stay.

An electronic and manual search of English- and French-language articles on TPVB in breast surgery (published from January 1980 to June 2010) yielded 41 citations. Two levels of screening identified 11 relevant studies. The Mantel-Haenszel method (fixed effect) was used to perform the meta-analysis.

Eleven studies were retained for analysis. When TPVB was used instead of GA, pain scores were significantly decreased at 1 and 6 h postoperatively (mean difference of 2.48 (95%confidence interval (CI): 2.20-2.75) and 1.71 (95%CI: 1.64-1.78), respectively). Furthermore, postoperative analgesic consumption was significantly lower in patients who received TPVB compared with GA (relative risk (RR) 0.23, (95%CI: 0.15-0.37)). TPVB was also associated with significantly less postoperative nausea and vomiting (RR 0.27 (95%CI: 0.12-0.61)). Increased patient satisfaction and a shorter hospital stay also favoured TPVB over GA.

TPVB provides effective anaesthesia for ambulatory breast surgery and can result in significant benefits over GA. However, further studies are required to determine whether these advantages would still be present if an optimal technique for outpatient GA is employed. Adjunctive ultrasonography may contribute to improve the safety of TPVB in breast surgery and requires further investigation.