Breast surgery is known being associated to a high risk of persistent post-operative pain, which has been related, among other factors, to a poorly treated acute pain. Paravertebral block has been successfully employed for anesthesia and analgesia after breast surgery, however its impact on persistent post-operative pain has rarely been investigated. Aim of this study is to assess prevalence, characteristics and consequences of post-discharge pain and its correlation to the incidence of persistent post-operative pain development in a continuous cohort of patients undergoing breast surgery with a paravertebral block.

Investigators designed a prospective, observational study on a continuous cohort of adult patients undergoing breast surgery with a standardized thoracic paravertebral block performed before general anesthesia induction. Patients were subsequently interviewed 6 months after hospital discharge in order to assess the incidence, features and duration of post-discharge pain.

Breast cancer is the most frequent cancer in women, with an incidence of more than one million new cases per year. In the majority of cases surgery is part of the treatment and prognosis has progressively improved during last years. Attention is thus being increasingly focusing on these patients' quality of life and chronic postsurgical pain, defined as pain in the area of surgery lasting beyond 3 month from the operation, has emerged as a frequent long-term complication, with prevalence up to 60%. This often-disabling condition has been shown to significantly affect cancer survivors' quality of life and to have a heavy economic impact on the healthcare system.

Many potential risk factors have been proposed for the development of chronic post-breast surgery pain. A Cochrane systematic review has addressed the role of regional anesthesia in preventing the development of chronic postoperative pain, suggesting that "paravertebral block may reduce the pain after breast cancer surgery in about one out every five women treated", these results being however weakened by the often poor quality and inadequate power of the studies available. Many predictors of chronic postoperative pain have been identified, one of them being a poorly treated acute pain; in this perspective, regional anesthesia could possibly play a role in preventing nervous system remodeling with resultant hyperalgesia, allodynia and sustained wound pain.

Even if chronic postoperative pain has been progressively recognized as an issue after breast cancer surgery, its link to poorly treated acute postoperative pain and post-discharge pain (PDP) has been poorly investigated. Single shot paravertebral block is an effective technique to provide both anesthesia and good analgesia after breast surgery, but its benefits duration is still debated.

Inclusion Criteria:

• female sex
• 18 years or greater
• elective breast surgery (tumor resection, mastectomy, lumpectomy)
• local regional anesthesia

Exclusion Criteria:

• patients refusal,
• general contraindications to regional anesthesia,
• the inability to perform a complete block
• diagnosed COPD or other respiratory diseases,
• ASA score risk greater than 3.

A consecutive cohort of adult patients undergoing breast surgery with a combined anesthesia technique, employing a thoracic single-shot paravertebral block performed before surgery. Operations performed were in all cases unilateral tumor resections, lumpectomies and mastectomies without axillary lymphadenectomy.