Paravertebral Blocks for Breast Cancer Surgery

This research project intends to look at the effect that a certain type of freezing injection, called a paravertebral block, has on the pain after an operation for breast cancer, the amount of pain relief that is needed and the side effects from this pain relief. The hypothesis is that the paravertebral block, in combination with a general anesthetic will reduce both pain scores and the amount of strong pain killers (opioids) that is needed. This will reduce the side effects of the pain killers such as nausea and vomiting. This will be assessed by comparing it a general anesthetic with pain killers given through the intravenous (IV) as is routine practice. Patients requiring breast cancer surgery, who agree to be involved in the trial, will be randomly allocated into two groups: both groups will receive a block, then a standardised and optimised general anesthetic. In one group however the block is simply a small injection under the skin (a sham block), whereas the other group will receive a proper paravertebral block prior to this. Both groups will receive opioids as necessary, depending on both their bodies reaction during the surgery and their pain scores when they wake up. The paravertebral block is a very safe procedure with a very low side effect profile, and many studies have shown a benefit in breast cancer surgery. The investigators would like to assess this in our own practice. The block is normally inserted under some light sedation, with freezing into the skin initially. It is normally very well tolerated. The sham block will also be performed under light sedation and freezing into the skin. The patients will not be able to tell whether they are having the sham block or the paravertebral block, because both are very well tolerated. There are no potential complications from the sham block.