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Background and Aims Primary breast cancer surgery (PBCS) is associated with chronic post-surgical pain, which can negatively affect health related quality of life (HRQOL). This randomized double-blind study aimed to determine if the number of injections with a thoracic paravertebral block (TPVB) can affect the risk of developing chronic pain after a PBCS.

Methods After ethics approval, 220 women undergoing PBCS were randomized to one of the two study groups: Group I: single-level TPVB (SL) with 25 ml of the study drug (0.5% levobupivacaine with 1:200,000 adrenaline) at T3 level and sham intramuscular injections at T1 and T5 level, or Group II: three-level TPVB (TL) at the T1,3 and 5 levels with 8,8, and 9 ml of the study drug respectively. All patients also received a standardized general anaesthesia (GA). The incidence of chronic pain between the groups at 3 and 6 months after surgery was our primary outcome measure. P<0.05 was considered statistically significant.

Results There was no significant difference in the incidence of chronic pain at 3 months (63% vs. 64%, P=0.92) and 6 months (63% vs. 61%, P=0.63) between SL and TL, respectively. The quality of recovery, risk of developing chronic pain, and physical and mental HRQOL also did not differ between the study groups (tables 1 & 2).

Conclusions The incidence, and risk, of chronic pain at 3 and 6 months after a PBCS is similar whether a single or three-level TPVB injection is used in conjunction with GA.